MedWorm: Aeromonas

Validation of a partial rpoB gene sequence as a tool for phylogenetic identification of aeromonads isolated from environmental sources

Canadian Journal of Microbiology — Sat, 20 Mar 2010 16:19:30 +0100

Brigitte Lamy, Fréderic Laurent, and Angeli Kodjo - A collection of 50 aeromonads isolated from environmental sources were studied, together with all known Aeromonas nomenspecies, by phenotypic, amplified 16S rDNA restriction analysis (16S... (Source: Canadian Journal of Microbiology)

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Detection and characterization of virulence genes and integrons in Aeromonas veronii isolated from catfish.

Food Microbiology — Wed, 17 Mar 2010 17:44:57 +0100

Authors: Nawaz M, Khan SA, Khan AA, Sung K, Tran Q, Kerdahi K, Steele R The presence of virulence genes and integrons was determined in 81 strains of Aeromonas veronii isolated from farm-raised catfish. Polymerase chain reaction (PCR) protocols were used to determine the presence of genes for cytotoxic enterotoxin (act), aerolysin (aerA), two cytotonic enterotoxins (ast, alt), lipase (lip), glycerophospholipid:cholesterol acyltransferase (gcaT), serine protease (ser), DNases (exu), elastase (ahyB) and the structural gene flagellin (fla) in the template DNA. Oligonucleotide primers amplified a 231-bp region of the act gene from the template DNA of 97.0% of the isolates. Primers specific for the amplification of the aerA gene amplified a 431-bp region of the aerA gene from the template D...

Metabolic engineering for microbial production of polyhydroxyalkanoates consisting of high 3-hydroxyhexanoate content by recombinant Aeromonas hydrophila.

Bioresource Technology — Mon, 15 Mar 2010 00:00:00 +0100

Authors: Jian J, Li ZJ, Ye HM, Yuan MQ, Chen GQ Polyhydroxyalkanoate synthase gene phaC(ah) in Aeromonas hydrophila strain 4AK4 was deleted and its function was replaced by phaC1(ps) cloned from Pseudomonas stutzeri strain 1317 which favors 3-hydroxyhexanoate (3HHx) and longer chain length monomers. Genes fadD and fadL encoding Escherichia coli acyl-CoA synthase and Pseudomonas putida KT2442 fatty acid transport protein, respectively, were introduced into the recombinant with new phaC1(ps). Accumulation of a series of novel medium-chain-length polyhydroxyalkanoates (mcl-PHA) consisting of 80-94mol% 3HHx were observed. The recombinant accumulated 54% poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) in cell dry weight consisting of 94.5mol% 3HHx or 51% poly(3-hydroxybutyrate-co-3-hydroxyhex...

Comparison of phenotypical and genetic identification of Aeromonas strains isolated from diseased fish.

Systematic and Applied Microbiology — Fri, 12 Mar 2010 00:00:00 +0100

Authors: Beaz-Hidalgo R, Alperi A, Buján N, Romalde JL, Figueras MJ Phenotypicaly identified Aeromonas strains (n=119) recovered mainly from diseased fish were genetically re-identified and the concordance between the results was analysed. Molecular characterization based on the GCAT genus specific gene showed that only 90 (75.6%) strains belonged to the genus Aeromonas. The 16S rDNA-RFLP method identified correctly most of the strains with the exception of a few that belonged to A. bestiarum, A. salmonicida or A. piscicola. Separation of these 3 species was correctly assessed with the rpoD gene sequences, which revealed that 5 strains with the RFLP pattern of A. salmonicida belonged to A. piscicola, as did 1 strain with the pattern of A. bestiarum. Correct phenotypic identificati...

First description of atypical furunculosis in freshwater farmed Atlantic salmon, Salmo salar L., in Chile

Journal of Fish Diseases — Mon, 08 Mar 2010 00:00:00 +0100

We report the first isolation, identification and characterization of a group of Chilean strains of atypical Aeromonas salmonicida isolated from freshwater farmed Atlantic salmon, Salmo salar. Affected fish showed superficial ulcers and pale liver with or without petechial haemorrhages. Outbreaks of the disease occurred in two farms in the south of Chile about 2200 km apart. Five strains were isolated in pure culture and identified by serological assays and immunofluorescence tests as belonging to Aeromonas salmonicida. Although the bacterial isolates were phenotypically homogeneous, minor differences with the reference strain A. salmonicida subsp. salmonicida ATCC 33658 were noted. Three specific primer sets and partial 16S rRNA gene sequencing allowed the identification of the Chilean is...

Aeromonas rivuli sp. nov. isolated from the upstream region of a karst water rivulet in Germany.

International Journal of Systematic and Evolutionary Microbiology — Fri, 05 Mar 2010 00:00:00 +0100

Authors: Figueras MJ, Alperi A, Beaz-Hidalgo R, Stackebrandt E, Brambilla E, Monera A, Martínez-Murcia AJ Two freshwater isolates (WB4.1-19(T) and WB4.4-101), sharing 99.9% 16S rRNA gene sequence similarity among each other, were highly related to members of Aeromonas sobria (99.7% similarity; 6 bp differences). A phylogenetic tree derived from the Multi-Locus-Phylogenetic-Analysis (MLPA) of concatenated sequences of 5 housekeeping genes (gyrB, rpoD, recA, dnaJ and gyrA; 3684 bp) clustered both strains as an independent phylogenetic line next to members of the species A. molluscorum and A. bivalvium. The DNA-DNA reassociation values obtained for these two isolates was 89.3%, and between strain WB4.1-19(T) and the type strains of the other species tested <70%. The phenotypic cha...

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Quinolone-resistant Aeromonas hydrophila peritonitis in a CAPD patient.

Clinical Nephrology — Fri, 26 Feb 2010 08:00:15 +0100

Authors: Sahin I, Barut HS Peritonitis is a major cause of morbidity in continuous ambulatory peritoneal dialysis (CAPD). Aeromonas hydrophila is a rare cause of peritonitis in patients on CAPD. We herewith report a 44-year-old female patient on CAPD with Aeromonas hydrophila peritonitis. Peritoneal fluid grew Aeromonas hydrophila. The patient reported that she had accidentally dropped her peritoneal dialysis catheter into the toilet. Susceptibility testing revealed that it is susceptible to ceftazidime, but resistant to ciprofloxacin. The patient was treated successfully with intravenous ceftazidime for 2 days followed by intraperitoneal ceftazidime for 12 days. She was discharged with complete recovery after 2 weeks of antibiotic treatment. PMID: 20178725 [PubMed - in process] (S...

Phytotherapy of ulcerative dermatitis induced by Aeromonas hydrophila infection in goldfish ( Carassius auratus ).

Acta Veterinaria Hungarica — Fri, 19 Feb 2010 11:28:36 +0100

Authors: Harikrishnan R, Balasundaram C, Moon YG, Kim MC, Kim JS, Dharaneedharan S, Heo MS Goldfish ( Carassius auratus ) weighing 13 +/- 2 g were administered intramuscularly a sublethal dose (1.8 x 10 3 cfu/ml) of Aeromonas hydrophila to induce ulcerative dermatitis. On day 3 and day 6 after infection the fish were dip-treated (for 5 min/day) with a tri-herbal concoction of Curcuma longa, Ocimum sanctum and Azadirachta indica (1%). The LD 50 value was recorded at a concentration of 2.3 x 10 4 between 30 and 36 days after infection. In the infected untreated group the cumulative mortality was higher, while in the early-treated group (day 3) there was no mortality. In the late-treated group (6th day) the mortality increased to 23.3% on day 36. In the infected group the size of ulcers p...

Proteome changes of Caenorhabditis elegans upon a Staphylococcus aureus infection

Biology Direct — Wed, 17 Feb 2010 00:00:00 +0100

Conclusions: Exploring four time-points discloses a dynamic insight of the reaction against a gram-positive infection at the level of the whole organism. The remarkable upregulation after 8h and 24h of many enzymes involved in the citric acid cycle might illustrate the cost of fighting off an infection. Intriguing is the downregulation of chaperone molecules, which are presumed to serve a protective role. A comparison with a similar experiment in which C. elegans was infected with the gram-negative Aeromonas hydrophila reveals that merely 9% of the identified spots, some of which even exhibiting an opposite regulation, are present in both studies. Hence, our findings emphasise the complexity and pathogen-specificity of the worm's immune response and form a firm basis for future functional ...

Distribution of Virulence Factors and Molecular Fingerprinting of Aeromonas Species Isolated from Water and Clinical Samples: Suggestive Evidence of Water-to-Human Transmission.

Applied and Environmental Microbiology — Fri, 12 Feb 2010 00:00:00 +0100

Authors: Khajanchi BK, Fadl AA, Borchardt MA, Berg RL, Horneman AJ, Stemper ME, Joseph SW, Moyer NP, Sha J, Chopra AK A total of 227 isolates of Aeromonas obtained from different geographical locations within the United States including 28 reference strains collected worldwide were analyzed for the presence of various virulence factors. These isolates were also finger-printed, using biochemical identification and pulse-field gel electrophoresis (PFGE). Of these 227 isolates, 199 collected from water and clinical samples belonged to three major Groups or Complexes, namely, A. hydrophila Group, A. caviae/media Group, and A. veronii/sobria Group, based on biochemical profiling, and they had various pulsotypes. In terms of virulence factor activities, Aeromonas isolates obtained from clini...

A novel multiplex polymerase chain reaction for simultaneous detection of yersinia enterocolitica, staphylococcus aureus, aeromonas and salmonella from chicken meat and milk samples

Journal of Food Safety — Thu, 11 Feb 2010 00:00:00 +0100

Yersinia enterocolitica, Staphylococcus aureus, Aeromonas and Salmonella are among the most important foodborne bacterial pathogens. The majority of human infections caused by all of these organisms are associated with ingestion of undercooked and contaminated meat, dairy products and water where in the secreted bacterial toxins lead to foodborne intoxications. We, here, report a new multiplex polymerase chain reaction (mPCR) assay for the simultaneous detection of these important foodborne bacterial pathogens. The mPCR targeted Ail and virF genes of Y. enterocolitica, nuc and entB genes of S. aureus, aerA and 16S rRNA genes of Aeromonas and invA, an invasion protein A gene of Salmonella. An internal amplification control designed to check the false negative reactions in mPCR was also incl...

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Biochemical characterization of three putative ATPases from a new type IV secretion system of Aeromonas veronii plasmid pAC3249A

BMC Biochemistry — Tue, 09 Feb 2010 00:00:00 +0100

Conclusions: This is the first biochemical characterization of conjugative transport ATPases encoded by a conjugative plasmid from Aeromonas. Our study demonstrated that the three ATPases of a newly reported TFSS of A. veronii plasmid pAc3249A are functional in both ATP hydrolysis and ATP binding. (Source: BMC Biochemistry)

PER-6, an extended-spectrum {beta}-lactamase from Aeromonas allosaccharophila.

Antimicrobial Agents and Chemotherapy — Tue, 09 Feb 2010 00:00:00 +0100

Authors: Girlich D, Poirel L, Nordmann P An Aeromonas allosaccharophila environmental isolate, recovered from the Seine river (Paris, France) produced a novel extended-spectrum beta-lactamase, PER-6, that shared 92% amino-acid identity with the closest beta-lactamase PER-2. The kinetic properties of PER-6 showed a slightly increased affinity for carbapenems. The blaPER-6 gene was chromosomally-located and bracketed by non-transposon related structures. PMID: 20145085 [PubMed - as supplied by publisher] (Source: Antimicrobial Agents and Chemotherapy)

A differential proteomics study of Caenorhabditis elegans infected with Aeromonas hydrophila.

Developmental and Comparative Immunology — Mon, 08 Feb 2010 00:00:00 +0100

This study confirms the involvement of galectins, C-type lectins and lipid binding proteins in the immunity of C. elegans. In addition a number of unknown proteins, which might represent important players of the worm's defence system, were isolated and identified. This work gives a first indication of the complex changes that occur at the protein level during infection. PMID: 20149819 [PubMed - as supplied by publisher] (Source: Developmental and Comparative Immunology)

Genetic and Biochemical Characterization of TRU-1, the Endogenous Class C {beta}-lactamase from Aeromonas enteropelogenes.

Antimicrobial Agents and Chemotherapy — Mon, 01 Feb 2010 00:00:00 +0100

Authors: De Luca F, Giraud-Morin C, Rossolini GM, Docquier JD, Fosse T Aeromonas enteropelogenes (formerly A. tructi) was described as an ampicillin-susceptible and cephalothin-resistant Aeromonas species, suggesting the production of a cephalosporinase. Strain ATCC 49803 was susceptible to amoxicillin, cefotaxime and imipenem but resistant to cefazolin (MICs 2, 0.032, 0.125 and >256 mug/ml, respectively) and produced an inducible beta-lactamase. CTX-resistant mutants (MIC, 32 mug/ml) could be selected in vitro that showed a constitutive beta-lactamase production. The gene coding for the cephalosporinase of A. enteropelogenes ATCC49803 was cloned and its biochemical properties investigated. E. coli transformants showing resistance to various beta-lactams carried a 3.5-kb plasmid ins...

Random amplified polymorphic DNA typing of clinical and environmental Aeromonas hydrophila strains from Limpopo province, South Africa.

Journal of Health, Population, and Nutrition — Mon, 01 Feb 2010 00:00:00 +0100

This study has demonstrated the genetic relatedness of Aeromonas hydrophila isolates from household drinking-water and clinical sources in South Africa, which may be due to cross-contamination from water to patients or vice-versa. This observation is of public-health significance, particularly in the era of HIV/AIDS. This study points to the importance of monitoring and evaluating infection-control measures for improved hygiene and to prevent cross-contaminations. PMID: 20214080 [PubMed - in process] (Source: Journal of Health, Population, and Nutrition)

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Aeromonas caviae strain induces Th1 cytokine response in mouse intestinal tract

Canadian Journal of Microbiology — Mon, 25 Jan 2010 17:37:43 +0100

Samuel L. Hayes, Dennis J. Lye, Craig A. McKinstry, and Stephen J. Vesper - Aeromonas caviae has been associated with human gastrointestinal disease. Strains of this species typically lack virulence factors (VFs) such as enterotoxins and hemolysins that are... (Source: Canadian Journal of Microbiology)

Use of lupin, Lupinus perennis, mango, Mangifera indica, and stinging nettle, Urtica dioica, as feed additives to prevent Aeromonas hydrophila infection in rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Mon, 25 Jan 2010 00:00:00 +0100

Feeding rainbow trout, Oncorhynchus mykiss (Walbaum), with 1% lupin, Lupinus perennis, mango, Mangifera indica, or stinging nettle, Urtica dioica, for 14 days led to reductions in mortality after challenge with Aeromonas hydrophila. In addition, there was significant enhancement in serum bactericidal activity, respiratory burst and lysozyme activity in the treatment groups compared to the controls. Use of lupin and mango led to the highest number of red blood and white blood cells in recipient fish, with use of stinging nettle leading to the highest haematocrit and haemoglobin values; the highest value of mean corpuscular volume and haemoglobin was in the control groups and those fed with stinging nettle. (Source: Journal of Fish Diseases)

OCCURRENCE OF PATHOGENIC MICROORGANISMS IN FISH SOLD IN SÃO PAULO, BRAZIL

Journal of Food Safety — Fri, 22 Jan 2010 00:00:00 +0100

This study investigated the presence of potentially human pathogenic strains of Vibrio spp., Aeromonas spp., Escherichia coli, Salmonella spp. and Staphylococcus aureus in fish commercialized in street markets of São Paulo city, Brazil. Twenty fish of different species were analyzed for foodborne pathogens using conventional methods. High levels of fecal contamination were detected in 25% of samples. S. aureus was isolated from 10% of samples. All were negative for Salmonella. Vibrio species, including Vibrio cholerae non-O1/non-O139, were observed in 85% of samples although Vibrio parahaemolyticus was not found in this study. Aeromonas spp., including A. hydrophila, was isolated from 50% of fish samples. The occurrence of these pathogens suggests that the fish commercialized in São Paul...

Immunoproteomics of extracellular proteins of the Aeromonas hydrophila China vaccine strain J-1 reveal a highly immunoreactive outer membrane protein

FEMS Immunology and Medical Microbiology — Wed, 20 Jan 2010 00:00:00 +0100

Aeromonas hydrophila is a gram-negative bacterium that can infect a variety of aquatic and terrestrial animals. It is essential to develop a vaccine to reduce the economic losses caused by this bacterium in aquaculture worldwide. Here, an immunoproteomic assay was used to identify the immunogenic extracellular proteins of the Chinese vaccine strain J-1. Ten unique immunogenic proteins were identified from the two-dimensional electrophoresis immunoblot profiles by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) or MALDI-TOF-TOF-MS. One protein of interest, Omp38, was detected by antisera on two-dimensional immunoblots, suggesting that it might be located both extracellularly and in the membrane. In exploring the potential of Omp38 as a vaccine can...

Immunoproteomics of extracellular proteins of the Aeromonas hydrophila China vaccine strain J-1 reveal a highly immunoreactive outer membrane protein

FEMS Immunology and Medical Microbiology — Tue, 19 Jan 2010 00:00:00 +0100

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The garlic component, allicin, prevents disease caused by Aeromonas hydrophila in rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Sun, 17 Jan 2010 00:00:00 +0100

Allicin was fed at 0 (= control), 0.5 and 1.0 mL of Allimed® liquid 100 g[minus]1 of feed for 14 days to rainbow trout, Oncorhynchus mykiss (Walbaum), fingerlings before infection with Aeromonas hydrophila with a resultant reduction in mortalities from 80% in the controls to 8% [relative percentage survival (RPS) = 90%] and 0% (RPS = 100%) among the treated fish. Allicin was strongly antibacterial compared to the control, with a minimum inhibitory concentration (MIC) of >400 [mu]L mL[minus]1 of Allimed® liquid. Use of allicin led to a lower number of white blood cells (132.0 ± 0.4 × 103) compared to 175.0 ± 0.1 × 103 in the controls, but elicited increased phagocytic activity, i.e. a phagocytic value of 39.2% compared to 13.6% in the controls, and serum lysozyme activity, which showe...

Lysozyme inhibitor conferring bacterial tolerance to invertebrate type lysozyme.

Cellular and Molecular Life Sciences : CMLS — Tue, 05 Jan 2010 00:00:00 +0100

Authors: Van Herreweghe JM, Vanderkelen L, Callewaert L, Aertsen A, Compernolle G, Declerck PJ, Michiels CW Invertebrate (I-) type lysozymes, like all other known lysozymes, are dedicated to the hydrolysis of peptidoglycan, the major bacterial cell wall polymer, thereby contributing to the innate immune system and/or digestive system of invertebrate organisms. Bacteria on the other hand have developed several protective strategies against lysozymes, including the production of periplasmic and/or membrane-bound lysozyme inhibitors. The latter have until now only been described for chicken (C-) type lysozymes. We here report the discovery, purification, identification and characterization of the first bacterial specific I-type lysozyme inhibitor from Aeromonas hydrophila, which we design...

The structure of the O-specific polysaccharide from the lipopolysaccharide of Aeromonas bestiarum strain 207.

Carbohydrate Research — Mon, 04 Jan 2010 00:00:00 +0100

Authors: Turska-Szewczuk A, Kozinska A, Russa R, Holst O The O-specific polysaccharide obtained by mild-acid degradation of Aeromonas bestiarum 207 lipopolysaccharide was studied by sugar and methylation analyses along with (1)H and (13)C NMR spectroscopy. The sequence of the sugar residues was determined by ROESY and HMBC experiments. It is concluded that the O-polysaccharide is composed of branched pentasaccharide repeating units of the following structure: PMID: 20080230 [PubMed - as supplied by publisher] (Source: Carbohydrate Research)

In vivo transfer of plasmid pRAS1 between Aeromonas salmonicida and Aeromonas hydrophila in artificially infected Cyprinus carpio L.

Journal of Fish Diseases — Sun, 03 Jan 2010 00:00:00 +0100

This study investigated the possible in vivo transfer of plasmid pRAS1 between Aeromonas salmonicida and A. hydrophila inhabiting two different organs of Cyprinus carpio L. To distinguish transconjugants from naturally occurring antibiotic resistant bacteria, twelve luminescent transposon-tagged A. hydrophila strains using miniTn5luxCDABEKm2 transposon were generated. In conjugal transfer experiments, fish were conditioned with the donor bacteria and subsequently immersed in water containing the recipient strain. Bacteria were recovered from gills and intestines and isolated by growth on selective plates. Transconjugants were identified by their resistance to the pRAS1 encoded antimicrobials and by light emission. In vivo transfer frequencies ranged between 10[minus]3 and 10[minus]6 and we...

The genus Aeromonas: taxonomy, pathogenicity, and infection.

Clinical Microbiology Reviews — Fri, 01 Jan 2010 00:00:00 +0100

This article provides an extensive review of these topics, in addition to others, such as taxonomic issues, microbial pathogenicity, and antimicrobial resistance markers. PMID: 20065325 [PubMed - in process] (Source: Clinical Microbiology Reviews)

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Burn wounds infected by contaminated water: Case reports, review of the literature and recommendations for treatment

Burns : Journal of the International Society for Burn Injuries — Wed, 23 Dec 2009 13:55:09 +0100

We report three cases of severe invasive and necrotizing infection in patients who used or immersed themselves in contaminated water in an attempt to extinguish the fire following acute major burns. Wound cultures from all patients yielded Aeromonas hydrophila and two yielded Bacillus cereus. One patient had a complex polymicrobial infection, including zygomycosis with Rhizomucor variabilis. All patients were treated aggressively with wound débridement, including one patient who required bilateral lower limb amputations to control progressive infection. All infections were successfully treated and all patients survived their burn injuries.We review the management of burns complicated by exposure to contaminated water leading to burn wound infections. We describe commonly reported organism...

Rapid identification and characterization of Vibrio species using whole-cell MALDI-TOF mass spectrometry

Journal of Applied Microbiology — Mon, 07 Dec 2009 00:00:00 +0100

Conclusions: The MALDI-TOF MS-based method as well as the rpoB sequence-based approach for Vibrio identification described in this study produced comparable classification results. The construction of phylogenetic trees from MALDI-TOF MS and rpoB sequences revealed a very good congruence of both methods.Significance and Impact of the Study: Our results suggest that whole-cell MALDI-TOF MS-based proteometric characterization represents a powerful tool for rapid and accurate classification and identification of Vibrio spp. and related species. (Source: Journal of Applied Microbiology)

The reference strain Aeromonas hydrophila CIP 57.50 should be reclassified as Aeromonas salmonicida CIP 57.50.

International Journal of Systematic and Evolutionary Microbiology — Fri, 04 Dec 2009 00:00:00 +0100

In this study we propose that the reference strain Aeromonas hydrophila CIP 57.50 be reclassified as Aeromonas salmonicida CIP 57.50 based on phenotypic characterization and sequence analyses of the genes cpn60, dnaJ, gyrB and rpoD. PMID: 19965992 [PubMed - as supplied by publisher] (Source: International Journal of Systematic and Evolutionary Microbiology)

Diversity of extracellular proteases among Aeromonas determined by zymogram analysis

Journal of Applied Microbiology — Fri, 04 Dec 2009 00:00:00 +0100

Conclusions: Aeromonas strains exhibited several extracellular proteolytic profiles, with a larger inter than intraspecific variation. Moreover, zymogram analyses allowed identifying new caseinases and gelatinases in Aeromonas.Significance and Impact of the Study: This is the first report on the intra- and interspecific variation of proteolytic profiles in Aeromonas determined by zymogram analysis, including the detection of new caseinases and gelatinases in this genus. (Source: Journal of Applied Microbiology)

Antilisterial Activity of a Broad-Spectrum Bacteriocin, Enterocin LR/6 from Enterococcus faecium LR/6.

Applied Biochemistry and Biotechnology — Thu, 03 Dec 2009 00:00:00 +0100

Authors: Kumar M, Srivastava S Enterocin LR/6, a purified bacteriocin, exhibited broad inhibitory spectrum both against related as well as some food-borne pathogens such as Listeria monocytogenes, Yersinia enterocolitica, Aeromonas sp., Shigella sp., and Bacillus licheniformis. In this investigation, we have focused on L. monocytogenes as the target organism, as it is not only an important pathogen but can also survive over a wide range of environmental conditions such as refrigeration temperature, low pH, and high-salt concentration. This allows the pathogen to overcome many food preservation and safety barriers and poses a potential risk to human health. The enterocin LR/6 showed a bactericidal action against L. monocytogenes and completely inhibited the growth on agar plates, supple...

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LOOP-MEDIATED ISOTHERMAL AMPLIFICATION – AN ASSAY FOR THE DETECTION OF ATYPICAL FURUNCULOSIS CAUSED BY AEROMONAS SALMONICIDA IN ATLANTIC COD, GADUS MORHUA

Journal of Rapid Methods and Automation in Microbiology — Wed, 02 Dec 2009 00:00:00 +0100

A loop-mediated isothermal amplification (LAMP)-based assay was developed for the detection of atypical furunculosis, caused by Aeromonas salmonicida in Atlantic cod, Gadus morhua. Gene gyrB encoding the B subunit of DNA gyrase present in the pathogen was selected for designing five sets of primers targeting the flanking regions of the gene. The primers were specific for the detection of A. salmonicida with no cross reactions to other bacterial pathogens commonly infecting Atlantic cod, e.g., Vibrio anguillarum, Francisella piscicida, Yersinia ruckeri and some endogenous bacteria found in the gut of Atlantic cod. The detection limit of the assay was 1 picogram of bacterial DNA mL[minus]1, whereas there was a decrease in detection limit by 1 log dilution in the presence of mucus as inhibito...

USE OF LOOP-MEDIATED ISOTHERMAL AMPLIFICATION ASSAY FOR THE DETECTION OF VIBRIO ANGUILLARUM O2β, THE CAUSATIVE AGENT OF VIBRIOSIS IN ATLANTIC COD, GADUS MORHUA

Journal of Rapid Methods and Automation in Microbiology — Wed, 02 Dec 2009 00:00:00 +0100

A loop-mediated isothermal amplification (LAMP)-based assay for the detection of Vibrio anguillarum O2[beta], the causative agent of vibriosis in Atlantic cod, Gadus morhua, was developed. Five sets of primers targeting the flanking regions of the genes, hemolysin and amiB, which encodes the peptidoglycan hydrolase N-acetylmuramoyl-L-alanine amidase of the pathogen were designed. The primers were specific for the detection of Vibrio anguillarum O2[beta] with no cross reactions to other bacterial pathogens commonly infecting Atlantic cod, e.g., Yersinia ruckeri, Francisella piscicida, Aeromonas salmonicida and some endogenous bacteria found in the gut of Atlantic cod. The detection limit of the assay was 10 pg of bacterial DNA/mL or 10 fg of bacterial DNA per LAMP reaction; however, the sen...

Prevalence of intestinal parasitic and bacterial pathogens in diarrhoeal and non-diarroeal human stools from Vhembe district, South Africa.

Journal of Health, Population, and Nutrition — Tue, 01 Dec 2009 00:00:00 +0100

Authors: Samie A, Guerrant RL, Barrett L, Bessong PO, Igumbor EO, Obi CL In the present study, a cross-sectional survey of intestinal parasitic and bacterial infections in relation to diarrhoea in Vhembe district and the antimicrobial susceptibility profiles of isolated bacterial pathogens was conducted. Stool samples were collected from 528 patients attending major public hospitals and 295 children attending two public primary schools and were analyzed by standard microbiological and parasitological techniques. Entamoeba histolytica/E. dispar (34.2%) and Cryptosporidium spp. (25.5%) were the most common parasitic causes of diarrhoea among the hospital attendees while Giardia lamblia (12.8%) was the most common cause of diarrhoea among the primary school children (p < 0.05). Schisto...

Identification and antimicrobial susceptibility of Aeromonas spp. isolated from stools of Brazilian subjects with diarrhoea and healthy controls.

Journal of Medical Microbiology — Thu, 26 Nov 2009 00:00:00 +0100

Authors: Surek M, Vizzotto BS, Souza EM, Pedrosa FD, Dallagassa CD, Farah SM, Fadel-Picheth CM Six hundred and eighty stool samples from patients with diarrhoea and 300 from healthy controls were analyzed for presence of Aeromonas and Plesiomonas. No Plesiomonas was found; however Aeromonas strains were isolated from samples of 18 patients with diarrhoea (2.6%) and from one healthy subject (0.3%). A. caviae was predominant. The response to cephalothin was similar, in most cases, to that of cefazolin. PMID: 19942692 [PubMed - as supplied by publisher] (Source: Journal of Medical Microbiology)

Aeromonas Septicemia After Medicinal Leech Use Following Replantation of Severed Digits.

American Journal of Critical Care — Wed, 25 Nov 2009 00:00:00 +0100

Authors: Levine SM, Frangos SG, Hanna B, Colen K, Levine JP Medicinal leeches are used to control venous congestion. Aeromonas in the leech gut are essential for digestion of blood. This case report describes a patient who had Aeromonas bacteremia develop after leeching. He had an injury to his hand that required replantation of his thumb. Following the surgery, leech therapy was started with ampicillin-sulbactam prophylaxis. Sepsis developed. Blood cultures were positive for Aeromonas that were resistant to ampicillin-sulbactam. The antibiotic was changed to ciprofloxacin on the basis of the sensitivity profile of the organisms. Cultures from the leech bathwater confirmed it as the source of the Aeromonas. Clinicians who use leech therapy must be aware that leeches can harbor Aeromona...

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A Bifunctional Enzyme in a Single Gene Catalyzes the Incorporation of GlcN into the Aeromonas Core Lipopolysaccharide [Membrane Transport, Structure, Function, and Biogenesis]

Journal of Biological Chemistry — Fri, 20 Nov 2009 14:36:52 +0100

The core lipopolysaccharide (LPS) of Aeromonas hydrophila AH-3 and Aeromonas salmonicida A450 is characterized by the presence of the pentasaccharide -d-GlcN-(1->7)-l--d-Hep-(1->2)-l--d-Hep-(1->3)-l--d-Hep-(1->5)--Kdo. Previously it has been suggested that the WahA protein is involved in the incorporation of GlcN residue to outer core LPS. The WahA protein contains two domains: a glycosyltransferase and a carbohydrate esterase. In this work we demonstrate that the independent expression of the WahA glycosyltransferase domain catalyzes the incorporation of GlcNAc from UDP-GlcNAc to the outer core LPS. Independent expression of the carbohydrate esterase domain leads to the deacetylation of the GlcNAc residue to GlcN. Thus, the WahA is the first described bifunctional glycosyltran...

A Multiplex PCR Method for the Detection of Three Enterotoxin Genes in Aeromonas spp.

Applied and Environmental Microbiology — Fri, 20 Nov 2009 00:00:00 +0100

Authors: Bin Kingombe CI, D'Aoust JY, Huys G, Hofmann L, Rao M, Kwan J A novel multiplex PCR method using three sets of specific primers was developed for the detection of the cytotoxic (act), heat-labile (alt), and heat-stable (ast) enterotoxin genes in Aeromonas spp. This assay was used to characterize 35 reference strains as well as 537 foodborne isolates. A total of 7 gene pattern combinations were encountered including act, alt, act/alt, act/alt/ast, act/alt/148 bp, alt/ast, and alt/148 bp. The alt gene was detected in 34 reference strains (97%), and occurred singly in 14% of these strains. The frequency of occurrence of the act/alt, act/alt/ast and alt/ast gene patterns in reference strains was 14 (40%), 2 (6%) and 2 (6%), respectively. An unpredicted amplicon was detected in 11 ...

Gene cloning, characterization, and heterologous expression of levansucrase from Bacillus amyloliquefaciens.

Journal of Industrial Microbiology and Biotechnology — Mon, 16 Nov 2009 00:00:00 +0100

In this study, we cloned and characterized the enzymatic kinetics using levansucrase expressed in Escherichia coli. Optimum pH for D: -glucose production and levan formation was 6.0 and 8.0, respectively, whereas optimum temperature was 30 degrees C and 4 degrees C, respectively. The K (m) and V (max) values for levansucrase were calculated to be 47.81 mM sucrose and 57.47 mumole/min mg protein, respectively. Prominent expression of levansucrase was obtained through xylose induction in Bacillus megaterium, where most of the His(6)-tagged protein was secreted into the culture broth, giving levansucrase activity of 12,906 U/l. Response-surface methodology (RSM) was further employed to optimize the fermentation conditions and improve the level of levansucrase production. Maximum levansucrase ...

Proteolytic activity among psychrotrophic bacteria isolated from refrigerated raw milk

International Journal of Dairy Technology — Thu, 12 Nov 2009 00:00:00 +0100

Psychrotrophic bacteria were isolated from refrigerated raw milk from a processing plant in Southern Brazil. Psychrotrophic counts were between 4.9 and 7.8 log cfu/mL, and 5.3 to 7.2 log cfu/mL, for samples collected at the truck and the milk storage silo, respectively. Among the bacterial isolates, 90% were Gram-negative. Most strains presented low proteolytic activity, but strains of Burkholderia cepacia, Klebsiella oxytoca and Aeromonas sp. showed higher than 20 U/mL on azocasein as substrate. Crude proteases from selected strains were resistant to conventional heat treatments and caused coagulation of UHT milk after 5 days storage at room temperature. (Source: International Journal of Dairy Technology)

Cellular components of probiotics control Yersinia ruckeri infection in rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Thu, 12 Nov 2009 00:00:00 +0100

Subcellular components of the probiotics Aeromonas sobria GC2 and Bacillus subtilis JB-1, when administered to rainbow trout, Oncorhynchus mykiss, conferred protection against a new biogroup of Yersinia ruckeri. Thus, intraperitoneal or intramuscular injection of rainbow trout with cell wall proteins (CWPs), outer membrane proteins (OMPs), lipopolysaccharides (LPS), whole cell proteins (WCPs) and live cells followed by challenge on day 8 with Y. ruckeri led to 80[ndash]100% survival compared with 10% survival in the controls. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) profiles of WCPs and OMPs from GC2 had 10 and 5 variable protein bands in comparison to 11 and 5 bands in the WCPs and CWPs from JB-1. Proteomic analyses were employed following SDS-PAGE to categori...

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Inhibition by Chestnut Honey of N-Acyl-l-homoserine Lactones and Biofilm Formation in Erwinia carotovora, Yersinia enterocolitica, and Aeromonas hydrophila

Journal of Agricultural and Food Chemistry — Tue, 10 Nov 2009 19:07:42 +0100

Journal of Agricultural and Food Chemistry, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable). (Source: Journal of Agricultural and Food Chemistry)

Growth condition and bacterial community for maximum hydrolysis of suspended organic materials in anaerobic digestion of food waste-recycling wastewater.

Applied Microbiology and Biotechnology — Fri, 06 Nov 2009 00:00:00 +0100

Authors: Kim MD, Song M, Jo M, Shin SG, Khim JH, Hwang S This paper reports the effects of changing pH (5-7) and temperature (T, 40-60 degrees C) on the efficiencies of bacterial hydrolysis of suspended organic matter (SOM) in wastewater from food waste recycling (FWR) and the changes in the bacterial community responsible for this hydrolysis. Maximum hydrolysis efficiency (i.e., 50.5% reduction of volatile suspended solids) was predicted to occur at pH 5.7 and T = 44.5 degrees C. Changes in short-chain volatile organic acid profiles and in acidogenic bacterial communities were investigated under these conditions. Propionic and butyric acids concentrations increased rapidly during the first 2 days of incubation. Several band sequences consistent with Clostridium spp. were detected usin...

The DC-SIGN of Zebrafish: Insights into the Existence of a CD209 Homologue in a Lower Vertebrate and Its Involvement in Adaptive Immunity.

Journal of Immunology — Wed, 04 Nov 2009 00:00:00 +0100

Authors: Lin AF, Xiang LX, Wang QL, Dong WR, Gong YF, Shao JZ Dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN/CD209) has become hot topic in recent studies because of its important roles in immune responses and immune escape. CD209 has been well characterized in humans and several other mammals, but little documentation exists about it in lower vertebrates. This is the first report on the identification and functional characterization of a fish DC-SIGN/CD209 molecule. The zebrafish DC-SIGN/CD209 cDNA translates into 343 aa organized into three domains structurally conserved among vertebrates. An EPN motif essential for interacting with Ca(2+) and for recognizing mannose-containing motifs has been identified. Several conserved motifs crucial for internalization and signal t...

The carboxy-terminal tail of Aeromonas sobria serine protease is associated with the chaperone

Microbiology and Immunology — Sun, 01 Nov 2009 00:00:00 +0100

ASP is the only bacterial protease in the kexin group of the subtilisin family. Previous studies have revealed that the ORF2 protein encoded at the 3' end of the asp operon is required for ASP to change from a nascent form into an active form in the periplasm. However, the mechanism by which ORF2 makes contact and interacts with ASP in the maturation process remains unknown. The present study examined the effect of mutations in the carboxy-terminal region of ASP on the ASP maturation process. Both deletion-mutation and amino acid-substitution studies have demonstrated that the histidine residue at position 595 (His-595), the sixth residue from the carboxyl terminus of ASP, is highly involved in the generation of active ASP molecules. An analysis by pull-down assay revealed that mutation at...

Hepatic gene expression profiling reveals protective responses in Atlantic salmon vaccinated against furunculosis

BMC Genomics - Latest articles — Fri, 30 Oct 2009 00:00:00 +0100

Conclusions: Efficiency of vaccination against furunculosis depends largely on the ability of host to neutralize the negative impacts of immune responses combined with efficient clearance and prevention of tissue damages. (Source: BMC Genomics - Latest articles)

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Plasmid-mediated QnrS2 determinant in an Aeromonas caviae isolate recovered from a patient with diarrhoea

Clinical Microbiology and Infection — Wed, 28 Oct 2009 00:00:00 +0100

Clin Microbiol Infect A qnrS2 gene was identified in an Aeromonas caviae isolate (MICs of ciprofloxacin, norfloxacin and ofloxacin >32 mg/L) from a stool sample collected from a patient with gastroenteritis. The analysis of the gyrA and parC genes revealed amino acid substitutions Ser83-Ile and Ser80-Thr, respectively. In addition, five out of 41 nalidixic acid-resistant Aeromonas isolates studied (26 identified as Aeromonas veronii bv sobria and 15 identified as A. caviae) showed ciprofloxacin resistance. The identification of plasmid-mediated qnr genes outside of the Enterobacteriaceae underlines a possible diffusion of these resistance determinants among Gram-negative rods. This emphasizes the importance of monitoring the emergence of these determinants as well as their dissemination am...

Design and Performance of a Turbot (Scophthalmus maximus) Oligo-microarray Based on ESTs from Immune Tissues.

Marine Biotechnology — Tue, 20 Oct 2009 23:00:00 +0100

Authors: Millán A, Gómez-Tato A, Fernández C, Pardo BG, Alvarez-Dios JA, Calaza M, Bouza C, Vázquez M, Cabaleiro S, Martínez P An expressed sequence tag database from immune tissues was used to design the first high-density turbot (Scophthalmus maximus) oligo-microarray with the aim of identifying candidate genes for tolerance to pathogens. Specific oligonucleotides (60 mers) were successfully designed for 2,716 out of 3,482 unique sequences of the database. An Agilent custom oligo-microarray 8 x 15 k (five replicates/gene; eight microarrays/slide) was constructed. The performance of the microarray and the sources of variation along microarray analysis were examined on spleen pools of controls and Aeromonas salmonicida-challenged fish at 3 days postinfection. O...

Simultaneous differential detection of human pathogenic and nonpathogenic Vibrio species using a multiplex PCR based on gyrB and pntA genes

Journal of Applied Microbiology — Tue, 20 Oct 2009 00:00:00 +0100

Conclusions: The multiplex PCR based on combined gyrB and pntA provides a high discriminatory power in the differentiation between Vibrio alginolyticus and V. parahaemolyticus, and between V. cholerae and Vibrio mimicus.Significance and Impact of the Study: This assay will be useful for rapid differentiation of various Vibrio species from clinical and environmental sources and significantly overcomes the limitations of the conventional methods. (Source: Journal of Applied Microbiology)

[Necrotizing fasciitis caused by Aeromonas hydrophila in an immunocompetent patient.]

Cirugia eEspanola — Fri, 09 Oct 2009 23:00:00 +0100

Authors: Fernández Arroyo M, González Romero D, Santana Cabrera L, Sánchez Palacios M PMID: 19822313 [PubMed - as supplied by publisher] (Source: Cirugia eEspanola)

Aeromonas taiwanensis sp. nov. and Aeromonas sanarellii sp. nov., two new clinical species from Taiwan.

International Journal of Systematic and Evolutionary Microbiology — Thu, 08 Oct 2009 23:00:00 +0100

Authors: Alperi A, Martínez-Murcia AJ, Ko WC, Monera A, Saavedra MJ, Figueras MJ Two clinical Aeromonas sp. strains (A2-50 and A2-67) recovered from the wounds of two patients in Taiwan could not be assigned to any known species of this genus based on the sequences of the 16S rDNA gene that showed similarities with A. caviae, A. trota and A. aquariorum ranging from 99.6% to 99.8%. The rpoD phylogenetic tree allocated these two strains to two new and independent phylogenetic lines, the neighbouring species being A. caviae showing 93.2% similarity (56 bp differences) with strain A2-50 and 92.2% (63 bp differences) with strain A2-67. A multi-locus phylogenetic analysis of 5 housekeeping genes (gyrB, rpoD, recA, dnaJ and gyrA; 3684 bp) confirmed both strains as independent phylogeneti...

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Aeromonas Sepsis as a Marker of Devitalized Tissue in Traumatic Injuries

Surgical Infections — Wed, 07 Oct 2009 13:45:34 +0100

Surgical Infections , Vol. 0, No. 0. (Source: Surgical Infections)

Detection and characterization of class 1 integrons in Aeromonas spp. isolated from human diarrheic stool in Mexico

Journal of Basic Microbiology — Mon, 05 Oct 2009 23:00:00 +0100

We determined the presence of class 1 integrons related to the acquisition of resistance to antimicrobials in Aeromonas spp. isolated from individuals with diarrhea. Species were identified as A. caviae, A. hydrophila, A. veronii and A. media using PCR-RFLP of the 16S rDNA. Selected isolates were further characterized by ERIC-PCR. Resistance to chloramphenicol, aztreonam, tetracycline, trimethoprim/sulfamethoxazole, nalidixic acid and streptomycin, among others, was determined using the Kirby-Bauer method. Integrons were detected by PCR amplification of the 5[prime] conserved, variable, and 3[prime] conserved regions. Sequencing of the variable regions revealed class 1 integrons with cassettes encoding resistance to trimethoprim (dfrA12, dfrA15, dfrB4), streptomycin/spectinomycin (aadA2, a...

Common Mechanistic Features among Metallo-{beta}-lactamases: A COMPUTATIONAL STUDY OF AEROMONAS HYDROPHILA CphA ENZYME [Enzyme Catalysis and Regulation]

Journal of Biological Chemistry — Fri, 02 Oct 2009 15:40:24 +0100

Metallo-β-lactamases (MβLs) constitute an increasingly serious clinical threat by giving rise to β-lactam antibiotic resistance. They accommodate in their catalytic pocket one or two zinc ions, which are responsible for the hydrolysis of β-lactams. Recent x-ray studies on a member of the mono-zinc B2 MβLs, CphA from Aeromonas hydrophila, have paved the way to mechanistic studies of this important subclass, which is selective for carbapenems. Here we have used hybrid quantum mechanical/molecular mechanical methods to investigate the enzymatic hydrolysis by CphA of the antibiotic biapenem. Our calculations describe the entire reaction and point to a new mechanistic description, which is in agreement with the available experimental evidence. Within our proposal, the z...

Aeromonas hydrophila sepsis in a preterm neonate.

Indian Pediatrics — Thu, 01 Oct 2009 00:00:00 +0100

Authors: Chaudhari T, Todd DA PMID: 19887702 [PubMed - in process] (Source: Indian Pediatrics)

Integration of microfiltration and anion-exchange nanoparticles-based magnetic separation with MALDI mass spectrometry for bacterial analysis.

Talanta — Wed, 30 Sep 2009 23:40:39 +0100

Authors: Li S, Guo Z, Liu Y, Yang Z, Hui HK Matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) is powerful in characterizing and identifying bacterial isolates. However, sufficient quantities of bacterial cells are required for generating MALDI mass spectra and a procedure to isolate and enrich target bacteria from sample matrix prior to MALDI-MS analysis is often necessary. In this paper, anion-exchange superparamagnetic nanoparticles (NPs), i.e., fluidMAG-DEAE and fluidMAG-Q, were employed to capture Aeromonas, Salmonella, Pseudomonas, Enterococcus, Bacillus, Staphylococcus and Escherichia coli from aqueous solutions and fresh water. The magnetically isolated bacteria were then characterized by whole cell MALDI-MS. The capture efficiency was found to be dependen...

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Structural Basis for the Kexin-like Serine Protease from Aeromonas sobria as Sepsis-causing Factor [Protein Structure and Folding]

Journal of Biological Chemistry — Thu, 24 Sep 2009 23:00:00 +0100

The anaerobic bacterium Aeromonas sobria is known to cause potentially lethal septic shock. We recently proposed that A. sobria serine protease (ASP) is a sepsis-related factor that induces vascular leakage, reductions in blood pressure via kinin release, and clotting via activation of prothrombin. ASP preferentially cleaves peptide bonds that follow dibasic amino acid residues, as do Kex2 (Saccharomyces cerevisiae serine protease) and furin, which are representative kexin family proteases. Here, we revealed the crystal structure of ASP at 1.65 Å resolution using the multiple isomorphous replacement method with anomalous scattering. Although the overall structure of ASP resembles that of Kex2, it has a unique extra occluding region close to its active site. Moreover, we found that a ...

Effect of oral immunization with Aeromonas hydrophila ghosts on protection against experimental fish infection

Letters in Applied Microbiology — Tue, 22 Sep 2009 23:00:00 +0100

Conclusions: Oral immunization with A. hydrophila ghosts can elicit systemic and mucosal adaptive immune responses and has higher potential to induce protective adaptive immunity than normal vaccine.Significance and Impact of the Study: Oral immunization with bacterial ghosts is a promising new solution with potential application to prevent diseases in fish. (Source: Letters in Applied Microbiology)

A novel method for the diagnosis of drowning by detection of Aeromonas sobria with PCR method

Legal Medicine — Fri, 18 Sep 2009 00:00:00 +0100

In this study, from the preserved blood samples of 32 freshwater drowning cases, specific DNA fragments of Aeromonas sobria, one of the most common aquatic bacteria, were examined using PCR. The DNA fragments of the bacterium were detected from 27 of 32 cases with first round PCR or nested-PCR. The remaining 5 cases in which bacterial DNA was not detected had longer storage periods for the blood samples and shorter time intervals from drowning to death. These results indicate that the present method can be applied to the diagnosis of death by drowning. (Source: Legal Medicine)

Identification and characterization of the first reptilian CD9, and its expression analysis in response to bacterial infection.

Developmental and Comparative Immunology — Tue, 08 Sep 2009 23:00:00 +0100

In this study, a CD9 homologue in a reptile, Chinese soft-shelled turtle, has been cloned and identified for the first time. The full-length cDNA of turtle CD9 was 1146bp and contained a 672bp open reading frame (ORF) coding for a protein of 224 amino acids. Four transmembrane domains (TMs) divided the turtle CD9 into several parts: short N, C-termini, an intracellular loop and two (small and large) extracellular loops (SEL and LEL). A CCG motif, a potential N-linked glycosylation site and ten cysteine residues were well conserved. The deduced amino acid sequence analysis showed that the turtle CD9 shared 82% identity to duck CD9. Most of the differences were found in the LEL. Phylogenetic analysis showed that the turtle CD9 sequence clustered together with bird CD9 sequence. RT-PCR analys...

Gene Cloning, Expression, and Characterization of Recombinant Aerolysin from Aeromonas hydrophila.

Applied Biochemistry and Biotechnology — Mon, 07 Sep 2009 23:00:00 +0100

Authors: Singh V, Somvanshi P, Rathore G, Kapoor D, Mishra BN Aerolysin is a significant virulent toxin protein secreted by Aeromonas hydrophila; it produces deep wound infections and hemorrhagic septicemia. The complete aerolysin gene (1,482 bp) was amplified from A. hydrophila. Furthermore, it was cloned and expressed into Escherichia coli BL21(DE3) codon plus RP cells using 0.5 mM IPTG for induction. The protein size was 54 kDa as estimated by SDS-PAGE, and it was purified by Ni-NTA affinity chromatography. Anti-His antibodies were used to characterize the expressed aerolysin by Western blotting and showed hemolytic activity with fish red blood cells. Aerolysin may be used as immunoassays for earlier control of A. hydrophila and is also compatible for vaccination. PMID: 19763901...

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N-Acyl homoserine lactones involved in quorum sensing control type VI secretion system, biofilm formation, protease production, and in vivo virulence from a clinical isolate of Aeromonas hydrophila.

Microbiology — Wed, 02 Sep 2009 23:00:00 +0100

In this study, we delineated the role of N-acyl homoserine lactone(s) (AHLs) mediated quorum sensing (QS) in the virulence of diarrheal isolate SSU of A. hydrophila by generating a double knockout DeltaahyRI mutant. The protease production was substantially reduced in the DeltaahyRI mutant when compared to that in the wild-type (WT) strain. Importantly, based on Western blot analysis, the DeltaahyRI mutant was unable to secrete type VI secretion system-associated effectors, namely hemolysin-co-regulated protein and the valine-glycine repeat family of proteins, while significant levels of these effectors were detected in the culture supernatant of the WT A. hydrophila. On the contrary, the production and translocation of the T3SS effector, AexU, in the human colonic epithelial cells were no...

An experimental vaccine against Aeromonas hydrophila can induce protection in rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Sat, 29 Aug 2009 23:00:00 +0100

A candidate vaccine against Aeromonas hydrophila in rainbow trout, Oncorhynchus mykiss, was developed using a bacterial lysate. To test the strength of protection, A. hydrophila challenge models were compared using injection into both the intraperitoneal (IP) cavity and the dorsal sinus (DS) with selected doses of live bacteria washed in saline or left untreated. Unlike the IP route, injection into the DS with either saline washed or unwashed cells resulted in consistent cumulative mortality and a dose response that could be used to establish a standard challenge having an LD50 of approximately 3 × 107 colony forming units per fish. Survivors of the challenge suffered significantly lower mortality upon re-challenge than naïve fish, suggesting a high level of acquired resistance was elici...

Occurrence of motile Aeromonas in municipal drinking water and distribution of genes encoding virulence factors.

International Journal of Food Microbiology — Fri, 21 Aug 2009 23:00:00 +0100

Authors: Pablos M, Rodríguez-Calleja JM, Santos JA, Otero A, García-López ML Aeromonas-associated cases of gastroenteritis are generally considered waterborne. The purpose of this study was to evaluate the potential microbiological risk associated with the presence of these bacteria in public drinking water. Over a period of one year, 132 drinking-water samples were monitored in León (NW of Spain, 137,000 inhabitants) for mandatory drinking-water standards and the occurrence of Aeromonas spp. Samples were taken at the municipal water treatment plant, one storage facility, and two public artesian drinking-water fountains. Because of low numbers of coliforms or Clostridium perfringens, the non-compliance rate with microbial standards was 3.8% whereas the percentage of...

Management of human and animal bite wound infection: An overview

Current Infectious Disease Reports — Mon, 17 Aug 2009 21:18:09 +0100

Abstract Animal and human bite wounds can lead to serious infections. The organisms recovered generally originate from the biter’s oral cavity and the victim’s skin flora. Anaerobes were isolated from more than two thirds of human and animal bite infections. Streptococcus pyogenes is often recovered in human bites, Pasteurella multocida in animal bites, Eikenella corrodens in animal and human, Capnocytophaga spp, Neisseria weaveri, Weeksella zoohelcum, Neisseria canis, Staphylococcus intermedius, nonoxidizer-1, and eugonic oxidizer-2 in dog, Flavobacterium group in pig, and Actinobacillus spp in horse and sheep bites. Vibrio spp, Plesiomonas shigelloides, Aeromonas hydrophila, and Pseudomonas spp can cause infections in bites associated with marine settings. In addition to...

Identification, Biosynthesis, and Characterization of Polyhydroxyalkanoate Copolymer Consisting of 3-Hydroxybutyrate and 3-Hydroxy-4-methylvalerate.

Biomacromolecules — Thu, 13 Aug 2009 23:00:00 +0100

In this study, we found that Ralstonia eutropha strain PHB(-)4 expressing the polyhydroxyalkanoate (PHA) synthase 1 (PhaC1(Ps)) from Pseudomonas sp. 61-3 synthesized a PHA copolymer containing a 3-hydroxybutyrate (3HB) and small amounts of 3-hydroxy-4-methylvalerate (3H4MV) and 3-hydroxyvalerate (3HV) from fructose as a sole carbon source. 3H4MV is a monomer unit that has hitherto not been reported as a naturally occurring component of PHAs. To increase the 3H4MV fraction in PHA copolymers, the culture medium was supplemented with four structural analogs that served as 3H4MV precursors. Of these, 4-methylvalerate (4MV) was the most efficient in increasing the 3H4MV content of PHA. The R. eutropha strain PHB(-)4 expressing Aeromonas cavaie PHA synthase (PhaC(Ac)) and its mutant (PhaC(Ac) NS...

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The Aeromonas hydrophila AH-3 T3SS expression: a study of its regulatory network.

Applied and Environmental Microbiology — Thu, 13 Aug 2009 23:00:00 +0100

In this study, we analysed the expression of the T3SS (type 3 secretion) regulon by analysing the activity of the aopN-aopD and aexT promoters (T3SS machinery components and effector, respectively) by means of two different techniques: promoterless-gfp fusions and Real Time PCR. The expression of A. hydrophila AH-3 T3SS regulon was induced in response to several environmental factors, of which calcium depletion, high magnesium concentration and high growth temperature were shown to be the major ones. Once the optimal conditions were established, we tested the expression of the T3SS regulon in the background of several virulence determinant knock-outs of strain AH-3. The analysis of the data obtained from axsA and aopN mutants, both of which have been described to be T3SS regulators in othe...

[Leech-borne infection on a TRAM flap: A case report.]

Annales de Chirurgie Plastique et Esthetique — Sun, 09 Aug 2009 23:00:00 +0100

We report a new case of delayed leech-borne infection in mammary reconstruction by a Transverse Rectus Abdominis Myocutaneous flap (TRAM) flap, which caused the flap loss. The use of prophylactic antibiotics is a way to prevent A.hydrophila infection (third generation cephalosporin, ciprofloxacin). This antibioprophylaxy must be followed until wound closure of the venous congested tissue. PMID: 19674823 [PubMed - as supplied by publisher] (Source: Annales de Chirurgie Plastique et Esthetique)

The structure of the di-zinc subclass B2 metallo-{beta}-lactamase CphA reveals that the second inhibitory zinc ion binds in the "histidine" site.

Antimicrobial Agents and Chemotherapy — Sun, 02 Aug 2009 23:00:00 +0100

Authors: Bebrone C, Delbrück H, Kupper MB, Schlömer P, Willmann C, Frère JM, Fischer R, Galleni M, Hoffmann KM Bacteria can defend themselves against beta-lactam antibiotics through the expression of class B beta-lactamases, which cleave the beta-lactam amide bond and render the molecule harmless. There are three subclasses of class B beta-lactamases (B1, B2 and B3), all of which require Zn(2+) for activity and can bind either one or two zinc ions. Whereas the B1 and B3 metallo-beta-lactamases are most active as di-zinc enzymes, subclass B2 enzymes such as Aeromonas hydrophila CphA are inhibited by the binding of a second zinc ion. We crystallized A. hydrophila CphA in order to determine the binding site of the inhibitory zinc ion. X-ray data from zinc-saturated crystals...

In vitro susceptibilities of aerobic and facultative anaerobic Gram-negative bacilli isolated from patients with intra-abdominal infections at a medical center in Taiwan: results of the Study for Monitoring Antimicrobial Resistance Trends (SMART) 2002-2006.

Journal of Microbiology, Immunology, and Infection — Sat, 01 Aug 2009 00:00:00 +0100

CONCLUSIONS: Continuous surveillance is crucial to monitor the trend of antimicrobial resistance patterns among GNB isolated from IAI. PMID: 19949755 [PubMed - in process] (Source: Journal of Microbiology, Immunology, and Infection)

Aeromonas fluvialis sp. nov., isolated from a Spanish river.

International Journal of Systematic and Evolutionary Microbiology — Thu, 30 Jul 2009 23:00:00 +0100

Authors: Alperi A, Martínez-Murcia AJ, Monera A, Saavera MJ, Figueras MJ A Gram-negative, facultatively anaerobic bacterial strain designated 717 was isolated from a water sample collected from the Muga river, Girona, north-east Spain. Preliminary analysis of the 16S rRNA gene sequence showed that this strain belonged to the genus Aeromonas, the nearest species being A. veronii (99.5% similarity, with 7 different nucleotides). A polyphasic study based on a Multilocus Phylogenetic Analysis of 5 housekeeping genes (gyrB, rpoD, recA, dnaJ and gyrA; 3684bp) showed isolate 717 as an independent phylogenetic line within the genus Aeromonas sobria, Aeromonas veronii and Aeromonas allosaccharophila being the closest neighbour species. DNA-DNA reassociation experiments and phenotypic analy...

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Isolation of faecal coliform bacteria from the American alligator (Alligator mississippiensis)

Journal of Applied Microbiology — Fri, 24 Jul 2009 23:00:00 +0100

Conclusions: A prevalence of enteric bacteria, both faecal coliforms and potential pathogens, was observed in American alligators. The high faecal coliform bacterial density of alligator faeces may suggest that alligators are a potential source of bacterial contamination in South Carolina coastal waters.Significance and Impact of the Study: These findings help to increase our understanding of faecal coliform and potential pathogenic bacteria from poikilothermic reptilian sources, as there is the potential for these sources to raise bacterial water quality levels above regulatory thresholds. (Source: Journal of Applied Microbiology)

Divergent evolution and purifying selection of the flaA gene sequences in Aeromonas

Biology Direct — Mon, 20 Jul 2009 23:00:00 +0100

Conclusions: The models applied to our set of sequences allowed us to determine the possible evolutionary pathway followed by the flaA gene in Aeromonas, suggesting that this gene have probably been evolving independently in the two groups of Aeromonas species since the divergence of a distant common ancestor after one or several episodes of positive selection.ReviewersThis article was reviewed by Alexey Kondrashov, John Logsdon and Olivier Tenaillon (nominated by Laurence D Hurst). (Source: Biology Direct)

Exploring threshold operation criteria of biostimulation for azo dye decolorization using immobilized cell systems.

Bioresource Technology — Mon, 20 Jul 2009 23:00:00 +0100

Authors: Chen BY, Yen CY, Chen WM, Chang CT, Wang CT, Hu YC This follow-up study provided an evaluation on threshold operation criteria of biostimulation in immobilized cell systems (ICSs) with Aeromonas hydrophila onto packing materials Porites corals. Essential nutrients in appropriate flow rate for biostimulation were inevitably required to maintain maximum attached cell population for cost-effective biodecolorization. With the method of "graphical reconstruction", the most economically feasible strategy of medium stimulation for color removal was quantitatively revealed. Our findings pointed out no matter what operation mode of reactor was (e.g., suspended batch cultures or ICS) color removal efficiency for A. hydrophila still strongly depended upon intrinsic kinetics and chemical ...

Antimicrobial resistance and in vitro gene transfer in bacteria isolated from the ulcers of EUS-affected fish in India

Letters in Applied Microbiology — Mon, 20 Jul 2009 23:00:00 +0100

Conclusions: The resistance to ampicillin, erythromycin, sulfadiazine, novobiocin and chloramphenicol is prevalent among the bacteria isolated from EUS-affected fish, and resistant determinants of some of these antibiotics have been transferred to the bacteria of other origin.Significance and Impact of the Study: The emergence of antibiotic resistance bacteria and gene transfer in vitro suggests that antibiotics should be used more cautiously to treat Aeromonas infections in aquaculture. (Source: Letters in Applied Microbiology)

Identification and pathogenicity to rainbow trout, Oncorhynchus mykiss (Walbaum), of some aeromonads

Journal of Fish Diseases — Thu, 09 Jul 2009 23:00:00 +0100

Twelve strains of fish pathogenic aeromonads were identified by 16S rRNA sequencing as Aeromonas bestiarum, A. hydrophila, A. hydrophila subsp. dhakensis, A. salmonicida subsp. salmonicida, A. sobria biovar sobria and A. veronii biovar sobria. Following intramuscular injection, A. hydrophila subsp. dhakensis caused dark liquefying, raised furuncle-like lesions in rainbow trout within 48 h. Extracellular products of all cultures contained gelatinase and lecithinase, and most revealed lipase. Congo red absorption and siderophore production was recorded, but not so the suicide phenomenon or slime production. Sodium dodecyl sulphate polyacrylamide gel electrophoresis profile of the outer membrane proteins (OMP) revealed 10[ndash]25 bands, of which major bands were seen in the region of 32.5[nd...

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In vivo modulation of immune response and antioxidant defense in Atlantic cod, Gadus morhua following oral administration of oxolinic acid and florfenicol.

Comparative biochemistry and physiology. Toxicology and pharmacology : CBP — Thu, 09 Jul 2009 23:00:00 +0100

Authors: Caipang CM, Lazado CC, Brinchmann MF, Berg I, Kiron V Oxolinic acid and florfenicol are the commonly used antibiotics for the treatment of bacterial diseases in Atlantic cod, Gadus morhua. The changes in selected innate humoral immune response of the fish, bacterial proliferation in serum and transcriptional activity of selected immune- and antioxidant defense-related genes following oral administration of these antimicrobial compounds were evaluated. Juvenile cod (75-100g) were fed commercial feed coated with either florfenicol (10mg kg(-1) fish, active ingredient) or oxolinic acid (20mg kg(-1) fish, active ingredient) at a ration of 0.5% body weight for 10 days. Whole blood and serum samples were collected on the 10th day of feeding the antibiotics and at 3, 5 and 10days aft...

Use of bacterial lipopolysaccharide (LPS) as an immunostimulant for the control of Aeromonas hydrophila infections in rainbow trout Oncorhynchus mykiss (Walbaum)

Journal of Applied Microbiology — Mon, 06 Jul 2009 23:00:00 +0100

Conclusions: LPS was effective at preventing disease caused by A. hydrophila and in stimulating the innate immune response of rainbow trout.Significance and Impact of the Study: The results of this study highlight the role of LPS in fish disease control. (Source: Journal of Applied Microbiology)

Characterization of electrochemical activity of a strain ISO2-3 phylogenetically related to Aeromonas sp. isolated from a glucose-fed microbial fuel cell

Biotechnology and Bioengineering — Wed, 01 Jul 2009 23:00:00 +0100

The microbial communities associated with electrodes in closed and open circuit microbial fuel cells (MFCs) fed with glucose were analyzed by 16S rRNA approach and compared. The comparison revealed that bacteria affiliated with the Aeromonas sp. within the Gammaproteobacteria constituted the major population in the closed circuit MFC (harvesting electricity) and considered to play important roles in current generation. We, therefore, attempted to isolate the dominant bacteria from the anode biofilm, successfully isolated a Fe (III)-reducing bacterium phylogenetically related to Aeromonas sp. and designated as strain ISO2-3. The isolated strain ISO2-3 could grow and concomitantly produce current (max. 0.24 A/m2) via oxidation of glucose or hydrogen with an electrode serving as the sole elec...

Phylogenetic analysis and identification of Aeromonas species based on sequencing of the cpn60 universal target.

International Journal of Systematic and Evolutionary Microbiology — Mon, 29 Jun 2009 23:00:00 +0100

In this study, cpn60 UT sequencing was shown to be a universal, useful, simple and rapid method for the identification and phylogenetic affiliation of Aeromonas strains. PMID: 19567585 [PubMed - as supplied by publisher] (Source: International Journal of Systematic and Evolutionary Microbiology)

PCR–DGGE-based methodologies to assess diversity and dynamics of Aeromonas communities

Journal of Applied Microbiology — Mon, 29 Jun 2009 23:00:00 +0100

Conclusions: The three systems used showed to be useful to describe the diversity of Aeromonas communities. However, the combined use of more than one primer set is advisable.Significance and Impact of the Study: The methods presented here can be applied to understand the natural pool of Aeromonas and also to monitor and control these bacteria in aquatic reservoirs. (Source: Journal of Applied Microbiology)

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Molecular characterization and expression profiles in response to bacterial infection of Chinese soft-shelled turtle interleukin-8 (IL-8), the first reptilian chemokine gene.

Developmental and Comparative Immunology — Sat, 27 Jun 2009 13:03:36 +0100

In this study, an IL-8 homologue has been cloned and identified from a reptile, Chinese soft-shelled turtle for the first time. The full-length cDNA of turtle IL-8 was 1188bp and contained a 312bp open reading frame (ORF) coding for a protein of 104 amino acids. The chemokine CXC domain, which contained Glu-Leu-Arg (ELR) motif and four cysteine residues, was well conserved in turtle IL-8. The 4924bp genomic DNA of turtle IL-8 contained four exons and three introns. Phylogenetic analysis showed that the amino acid sequence of turtle IL-8 clustered together with birds. RT-PCR analysis showed that turtle IL-8 mRNA was constitutively expressed liver, spleen, kidney, heart, blood and intestine tissues of control turtles. Real-time quantitative PCR analysis further indicated that the turtle IL-8...

Crystallization and preliminary X-ray diffraction studies of AsaP1_E294A and AsaP1_E294Q, two inactive mutants of the toxic zinc metallopeptidase AsaP1 from Aeromonas salmonicida subsp. achromogenes

Acta Crystallographica Section F — Fri, 26 Jun 2009 23:00:00 +0100

Two mutants of the toxic extracellular zinc endopeptidase AsaP1 (AsaP1_E294Q and AsaP1_E294A) of Aeromonas salmonicida subsp. achromogenes were expressed in Escherichia coli and crystallized by the vapour-diffusion method. Crystals were obtained using several precipitants and different protein concentrations. Protein crystals were found in a monoclinic (C2) as well as an orthorhombic (P212121) space group. The crystals belonging to the monoclinic space group C2 had unit-cell parameters a = 103.4, b = 70.9, c = 54.9 Å, β = 109.3° for AsaP1_E294A, and a = 98.5, b = 74.5, c = 54.7 Å, β = 112.4° for AsaP1_E294Q. The unit-cell parameters of the orthorhombic crystal obtained for AsaP1_E294A were a = 57.9, b = 60.2, c = 183.6 Å. The crystals of the two different mutants diffracte...

Effect of Lactococcus lactis CLFP 100 and Leuconostoc mesenteroides CLFP 196 on Aeromonas salmonicida Infection in Brown Trout (Salmo trutta)

Journal of Molecular Microbiology and Biotechnology — Thu, 25 Jun 2009 23:00:00 +0100

J Mol Microbiol Biotechnol (DOI:10.1159/000226588) (Source: Journal of Molecular Microbiology and Biotechnology)

Occurrence of heavy metals and antibiotic resistance in bacteria from internal organs of american bullfrog (Rana catesbeiana) raised in Malaysia

Journal of Venomous Animals and Toxins including Tropical Diseases — Thu, 25 Jun 2009 09:03:01 +0100

A total of 40 bacteria have been successfully isolated from internal organs of the American bullfrog (Rana catesbeiana) raised in Malaysia, namely, eight isolates of Aeromonas spp., 21 of Edwardsiella spp., six of Flavobacterium spp. and five of Vibrio spp. In terms of antibiotic susceptibility testing, each isolate was tested against 21 antibiotics, resulting in 482 (57.3%) cases of sensitivity and 61 (7.3%) cases of partial sensitivity. Meanwhile, 297 (35.4%) bacterial isolates were registered as resistant. The multiple antibiotic resistance (MAR) index of each bacterial species indicated that bacteria from raised bullfrogs have been exposed to tested antibiotics with results ranging from 0.27 to 0.39. Additionally, high percentages of heavy metal resistance among these isolates were obs...

Infections in Patients With Aplastic Anemia

Seminars in Hematology — Thu, 25 Jun 2009 07:43:55 +0100

Infection is a major cause of death in patients with aplastic anemia (AA). There are differences between the immunocompromised state of a patient with AA and the patient who is neutropenic due to chemotherapy and this leads to a difference in the infections that they incur. Prolonged neutropenia is one of the largest risk factors for the development of infections with the invasive mycoses and bacteria. Recovery from neutropenia is directly related to survival, and supportive care plays a large role in protection while the patient is in a neutropenic state. The most common invasive mycoses include the Aspergillus species, Zygomycetes, Candida spp., and Fusarium spp. Bacterial infections that are seen in patients with AA include gram-positive coagulase-negative Staphylococcus species, Entero...

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Prevalence of Genes Encoding the Type Three Secretion System and the Effectors AexT and AexU in the Aeromonas veronii Group

DNA and Cell Biology — Wed, 17 Jun 2009 20:34:29 +0100

DNA and Cell Biology , Vol. 0, No. 0. (Source: DNA and Cell Biology)

New Structural Variants of Homoserine Lactones in Bacteria.

Chembiochem — Mon, 15 Jun 2009 23:00:00 +0100

In this study we describe for the first time the occurrence of acyl chains carrying a methyl branch, and present a GC-MS-based method that can be used to distinguish these compounds from unbranched isomers. The bacterium Aeromonas culicicola produces several methyl branched AHLs. In Jannaschia helgolandensis-a marine bacterium of the Roseobacter clade-a doubly unsaturated AHL, (2E,9Z)-N-(2,9-hexadecadienoyl)-L-homoserine lactone, occurs. The location and configuration of the double bonds was proven by spectrometric investigation and synthesis. Finally, a method was developed to establish the absolute configuration of 3-hydroxyalkanoyl-HSLs by mild cleavage and chiral gas chromatography. The AHLs synthesized during this study were tested in sensor systems specific for certain AHL types. The...

Inhibition of frog antimicrobial peptides by extracellular products of the bacterial pathogen Aeromonas hydrophila

Letters in Applied Microbiology — Sun, 14 Jun 2009 23:00:00 +0100

Conclusion: The proteolytic ECPs of Aer. hydrophila have the ability to inhibit the skin antimicrobial peptides of frogs.Significance and Impact of the Study: The results of this study provide new information on the association of ECPs with the resistance of Aer. hydrophila to frog antimicrobial peptides. (Source: Letters in Applied Microbiology)

Quantitative analysis of bacterial adhesion to fish tissue.

Colloids and Surfaces — Sat, 13 Jun 2009 08:00:49 +0100

Authors: Vendrell D, Balcázar JL, Calvo AC, de Blas I, Ruiz-Zarzuela I, Gironés O, Múzquiz JL Adhesion to host tissue represents a first crucial step in most bacterial infections. Both specific adhesion-ligand as well as hydrophobic interactions may be involved. The adhesion of Aeromonas salmonicida subsp. salmonicida, Lactococcus garvieae, and Yersinia ruckeri strains to fish tissue cells was assessed. To determine whether the observed bacterial adhesion to fish tissue cells was caused by non-specific interactions, adhesion to bovine serum albumin (BSA) and polystyrene was also tested. Our results demonstrated that non-specific adhesion such as hydrophobic interactions are only partially involved in the binding process since adhesion to BSA was low, and there was no cor...

Elimination of symbiotic Aeromonas spp. from the intestinal tract of the medicinal leech, Hirudo medicinalis, using ciprofloxacin feeding

Clinical Microbiology and Infection — Wed, 10 Jun 2009 23:00:00 +0100

Clin Microbiol Infect The use of the medicinal leech (Hirudo medicinalis) in promoting venous drainage in tissues whose vitality is threatened by venous congestion and obstruction, especially in plastic and reconstructive surgery, has been complicated by infections caused by Aeromonas spp. These are leech endosymbionts for which patients undergoing hirudotherapy frequently receive systemic chemoprophylaxis. In order to evaluate the possibility of rendering leeches safe for use on patients, H. medicinalis were fed artificially with a 2 g/L arginine solution (used as a phagostimulant) supplemented with ciprofloxacin (100 mg/L). Aeromonads were detected in 57 out of 80 control leeches (71.3%), but in none of the 56 leeches treated with ciprofloxacin (p (Source: Clinical Microbiology and Infec...

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Methylprednisolone: Diabetes, fatal Aeromonas sobria sepsis and rhabdomyolysis in an HIV- and HCV-positive patient: case report

Reactions — Tue, 09 Jun 2009 16:41:07 +0100

(Source: Reactions)

Methylprednisolone: Diabetes, fatal Aeromonas sobria sepsis and rhabdomyolysis in an HIV- and HCV-positive patient: case report.

Reactions Weekly — Sun, 07 Jun 2009 18:23:59 +0100

Page: 23 (Source: Reactions Weekly)

The effect of hyperoxygenation and reduced flow in fresh water and subsequent infectious pancreatic necrosis virus challenge in sea water, on the intestinal barrier integrity in Atlantic salmon, Salmo salar L.

Journal of Fish Diseases — Wed, 03 Jun 2009 23:00:00 +0100

In high intensive fish production systems, hyperoxygenation and reduced flow are often used to save water and increase the holding capacity. This commonly used husbandry practice has been shown to be stressful to fish and increase mortality after infectious pancreatic necrosis virus (IPNV) challenge, but the cause and effect relationship is not known. Salmonids are particularly sensitive to stress during smoltification and the first weeks after seawater (SW) transfer. This work aimed at investigating the impact of hyperoxygenation combined with reduced flow in fresh water (FW), on the intestinal barrier in FW as well as during later life stages in SW. It further aims at investigating the role of the intestinal barrier during IPNV challenge and possible secondary infections. Hyperoxygenatio...

High frequency of hemolytic and cytotoxic activity in Aeromonas spp. isolated from clinical, food and environmental in Rio de Janeiro, Brazil.

Antonie van Leeuwenhoek — Mon, 01 Jun 2009 04:00:00 +0100

Authors: Castilho MC, Castro TL, Araújo VS, Trajano RS, Santos PA, Pimenta PM, Lucheze K, Melo JT, Gonçalves AM, Nogueira RT, de Luna MG, Freitas-Almeida AC Molecular study of aerolysin and cytotonic enterotoxin genes by PCR and colony blot hybridization was performed in 117 strains of Aeromonas spp. isolated from different sources. Homogeneous distribution of these genes in A. hydrophila complex strains was observed. For A. caviae and A. sobria complex strains, aerolysin genes were more frequent than cytotonic enterotoxins genes. Of 64 A. caviae complex strains, only one (1.5%) amplified the 451 bp product for the aer gene, however, the same primers detected a 400 bp product in 50 (78%) strains. This product was sequenced and had two short regions with homology to several he...

Oral bacterial flora of the Chinese cobra (Naja atra) and bamboo pit viper (Trimeresurus albolabris) in Hong Kong SAR, China.

Hong Kong Med J — Sun, 31 May 2009 23:00:00 +0100

CONCLUSION: 'Prophylactic' antibiotic treatment for Chinese cobra bites may be beneficial, owing to the multiple pathogenic bacteria in its oral cavity and the higher risk of ensuing necrosis. The regimen of levofloxacin plus amoxicillin/clavulanate appears promising for this purpose, but further study is required to confirm its clinical utility in patients. PMID: 19494373 [PubMed - in process] (Source: Hong Kong Med J)

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Biosynthesis and characterization of 3-hydroxyalkanoate terpolyesters with adjustable properties by Aeromonas hydrophila

Biotechnology and Bioengineering — Wed, 27 May 2009 23:00:00 +0100

Polyhydroxyalkanoates (PHA) terployesters P(3HB-co-3HV-co-3HHx) consisting of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyhexanoate (3HHx) were produced by wild-type Aeromonas hydrophila 4AK4, its recombinant harboring PHA synthesis genes phaPCJ encoding PHA binding protein phasin, PHA synthase, and enoyl-CoA hydratase, and another its recombinant harboring phaAB encoding beta-ketothiolase and acetoacetyl-CoA reductase, respectively, when grown in lauric acid and/or valerate. The terpolyesters produced by A. hydrophila 4AK4 (phaAB) grown in velarate were found to produce copolymers P(3HB-co-3HV) containing high 3HV fractions with a maximum of 99 mol% 3HV. In terpolyesters, 3HV ranged from 9 to 32 mol% depending on the valerate concentration and strain used. A maximal ter...

Soybean meal alters autochthonous microbial populations, microvilli morphology and compromises intestinal enterocyte integrity of rainbow trout, Oncorhynchus mykiss (Walbaum)

Journal of Fish Diseases — Wed, 27 May 2009 23:00:00 +0100

Rainbow trout were fed either a diet containing fishmeal (FM) as the crude protein source or a diet containing 50% replacement with soybean meal (SBM) for 16 weeks. An enteritis-like effect was observed in the SBM group; villi, enterocytes and microvilli were noticeably damaged compared with the FM group. The posterior intestine microvilli of SBM-fed fish were significantly shorter and the anterior intestine microvilli significantly less dense than the FM-fed fish. Electron microscopy confirmed the presence of autochthonous bacterial populations associated with microvilli of both fish groups. Reduced density of microvilli consequently led to increased exposure of enterocyte tight junctions, which combined with necrotic enterocytes is likely to diminish the protective barrier of the intesti...

Prevalence and transmission of antimicrobial resistance among Aeromonas populations from a duckweed aquaculture based hospital sewage water recycling system in Bangladesh.

Antonie van Leeuwenhoek — Thu, 21 May 2009 04:00:00 +0100

Authors: Rahman M, Huys G, Kühn I, Rahman M, Möllby R In order to investigate the influence of a duckweed aquaculture based hospital sewage water recycling plant on the prevalence and dissemination of antibiotic resistance, we made use of an existing collection of 1,315 Aeromonas isolates that were previously typed by the biochemical fingerprinting PhP-AE system. In these treatment plant, hospital raw sewage water is first collected in a settlement pond (referred to as sewage water in this study) and is then transferred to a lagoon, where the duckweed (Lemnaceae) is grown (referred to as lagoon). The duckweed is harvested and used as feed for the fish in a separate pond (referred to as fish pond). From this collection, representatives of 288 PhP types were subjected to antibi...

Pioneer colonizer microorganisms in biofilm formation on galvanized steel in a simulated recirculating cooling-water system

Journal of Basic Microbiology — Tue, 19 May 2009 04:00:00 +0100

We examined biofilm formation and first attachment maintance of biofilms of Pseudomonas spp., Pseudomonas aeruginosa, Aeromonas spp, sulphate reducing bacteria and filamentous fungi. A simulated recirculating cooling-water system was used. Heterotrophic bacteria counts on galvanized steel and glass surfaces rose during the tidy period of 720 hours. In addition, we determined that although Pseudomonas spp., Pseudomonas aeruginosa and Aeromonas spp. were the pioneer colonizers, they surprisingly could not be determined in the biofilms on both types of surface after 456 hours. Sulphate reducing bacteria were observed in biofilms on both surfaces from the outset of the experiments. Filamentous fungi were seen on the galvanized steel and glass surfaces after 0.5 h. (© 2009 WILEY-VCH Verlag Gmb...

Identification and analysis of differentially expressed genes in immune tissues of Atlantic cod stimulated with formalin-killed, atypical Aeromonas salmonicida

Physiological Genomics — Wed, 13 May 2009 04:00:00 +0100

This study is the first large-scale discovery of bacteria-responsive genes in cod and the first to demonstrate upregulation of IRF1 in fish immune tissues as a result of bacterial antigen stimulation. Given the importance of IRF1 in vertebrate immune responses to viral and bacterial pathogens, the full-length cDNA sequence of Atlantic cod IRF1 was obtained and compared with putative orthologous sequences from other organisms. Functional annotations of assembled SSH library ESTs showed that bacterial antigen stimulation caused changes in many biological processes including chemotaxis, regulation of apoptosis, antimicrobial peptide production, and iron homeostasis. Moreover, differences in spleen and head kidney gene expression responses to the bacterial antigens pointed to a potential role ...

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Cloning and expression of an outer membrane protein OmpW of Aeromonas hydrophila and study of its distribution in Aeromonas spp.

Journal of Applied Microbiology — Wed, 06 May 2009 04:00:00 +0100

Conclusions: The ompW-based PCR method developed in this study was found to be 100% specific and 97% sensitive. Expression of OmpW protein of Aeromonas was found to be salt-dependant. Recombinant OmpW protein was found to be highly immunogenic in fish.Significance and Impact of the Study: To our knowledge, this is the first report on cloning and expression of OmpW protein of A. hydrophila. Full-length ompW gene amplification by PCR can be used for the detection of Aeromonas. Recombinant OmpW protein can be useful for vaccination of fish against Aeromonas spp. (Source: Journal of Applied Microbiology)

Antibiotic-Resistant Organisms Cultured from Atlantic Bottlenose Dolphins (Tursiops truncatus) Inhabiting Estuarine Waters of Charleston, SC and Indian River Lagoon, FL

EcoHealth — Tue, 05 May 2009 06:11:03 +0100

Abstract Bottlenose dolphins (Tursiops truncatus) from estuarine waters of Indian River Lagoon, FL (IRL) and Charleston, SC (CHS) were cultured to screen for microorganism colonization and to assess antibiotic sensitivity. Swabs (n = 909) were collected from the blowhole, gastric fluid, and feces of 171 individual dolphins The most frequently cultured organisms were Plesiomonas shigelloides (n = 161), Aeromonas hydrophila (n = 144), Escherichia coli (n = 85), and Pseudomonas fluorescens (n = 82). In descending frequency, organisms demonstrated resistance to erythromycin, ampicillin, and cephalothin. Human and animal pathogens resistant to antibiotics used in human and veterinary medicine were cultured. Escherichia coli (E. col...

Application of an immunoaffinity-based preconcentration method for mass spectrometric analysis of the O-chain polysaccharide of Aeromonas salmonicida from in vitro- and in vivo-grown cells

FEMS Microbiology Letters — Wed, 29 Apr 2009 04:00:00 +0100

In this study, application of magnetic beads (Dynabeads) coated with Aeromonas salmonicida lipopolysaccharide-specific polyclonal antisera to MS-based characterization of bacterial lipopolysaccharides has been evaluated. The results showed that the affinity-based preconcentration strategy resulted in at least a 100-fold increase in the detection of sensitivity, affording direct capillary electrophoresis (CE)-MS analysis of A. salmonicida lipopolysaccharide O-chain polysaccharide from in vitro-cultured cells. Subsequent CE-MS analysis of in vivo-grown cells of A. salmonicida confirmed significant changes in the structure of the lipopolysaccharide O-chain polysaccharide as a result of in vivo cultivation. (Source: FEMS Microbiology Letters)

Rapid Aeromonas hydrophila identification by TaqMan PCR assay: comparison with a phenotypic method

Letters in Applied Microbiology — Fri, 24 Apr 2009 04:00:00 +0100

Conclusions: The PCR developed here was successfully applied for the identification of Aer. hydrophila from reference, clinical and environmental samples and showed a high discrimination between Aer. hydrophila and other Aeromonas species.Significance and Impact of the Study: This molecular method is convenient, rapid (2·5 h vs 24 h), specific to identify Aer. hydrophila and usable for diagnosis in medical and veterinary laboratories. (Source: Letters in Applied Microbiology)

Aeromonas sobria sepsis complicated by rhabdomyolysis in an HIV-positive patient: case report and evaluation of traits associated with bacterial virulence

International Journal of Infectious Diseases — Wed, 22 Apr 2009 11:02:50 +0100

Summary: Human infection with Aeromonas species is uncommon and most often due to trauma with exposure to contaminated water or soil. A 43-year-old HIV- and hepatitis C virus (HCV)-infected male, after a two-week course of corticosteroid therapy for an autoimmune anemia, developed diarrhea, dermatologic manifestations and a multiple organ dysfunction syndrome, resulting in death. Although stool samples were repeatedly negative, two sets of blood cultures obtained during a single peak of fever yielded the post-mortem isolation of a Gram-negative, oxidase-positive, β-hemolytic bacillus that was identified as Aeromonas sobria. Empiric antibiotic therapy was unsuccessful. Evaluation of the virulence-associated traits of the clinical isolate (adhesion, cytotoxicity activity, biofilm production...

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Detection of metallo-β-lactamases-encoding genes in environmental isolates of Aeromonas hydrophila and Aeromonas jandaei

Letters in Applied Microbiology — Wed, 22 Apr 2009 04:00:00 +0100

Conclusions: Our results indicate that cphA seems to be intrinsic in the environmental isolates of Aer. hydrophila and Aer. jandaei in southeastern Brazil, although, based on the combined disk test, not all of them are apparently able to express the enzymatic activity.Significance and Impact of the Study: These data confirm the presence of MBL-producing Aeromonas species in natural water reservoirs. Risk of waterborne diseases owing to domestic and industrial uses of freshwater should be re-examined from the increase of bacterial resistance point of view. (Source: Letters in Applied Microbiology)

Comparative metagenomics of Daphnia symbionts

BMC Genomics - Latest articles — Tue, 21 Apr 2009 04:00:00 +0100

Conclusions: Three clones from three species of the genus Daphnia were found to harbor a rich community of symbionts. These communities are similar at the genus and higher taxonomic level, but are composed of different species. The similarity of these three symbiont communities hints that some of these associations may be stable in the long-term. (Source: BMC Genomics - Latest articles)

Biocompatibility of poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) with bone marrow mesenchymal stem cells

Acta Biomaterialia — Sat, 18 Apr 2009 21:15:07 +0100

Abstract: As a new member of the polyhydroxyalkanoate (PHA) family, poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (PHBVHHx) was produced by recombinant Aeromonas hydrophila 4AK4. PHBVHHx showed a rougher surface and had higher hydrophobicity than the well-studied polymers poly(l-lactic acid) (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx). Human bone marrow mesenchymal stem cells (MSCs) adhered better on PHBVHHx film than on tissue culture plates (TCPs), PLA film and PHBHHx film. The cell number on the PHBVHHx film was 115% higher than that on the TCPs, 66% higher than on the PHBHHx film and 263% higher than on the PLA film (p (Source: Acta Biomaterialia)

A qRT-PCR-based method for the measurement of rrn operon copy number

Letters in Applied Microbiology — Fri, 17 Apr 2009 04:00:00 +0100

Conclusions: The whole cell qRT-PCR based methods were convenient, accurate and reproducible in quantification of rrn copy number of prokaryotic cells.Significance and Impact of the Study: qTR-PCR is a fast and reliable DNA quantification approach. Compared with previous qTR-PCR based methods measuring rrn copy number, the present method avoided the prerequisite for the information on genome size and GC content of target bacteria or a gene with known copy number, thus should be more widely applicable. (Source: Letters in Applied Microbiology)

Ingestion of bacteria overproducing DnaK attenuates Vibrio infection of Artemia franciscana larvae.

Cell Stress and Chaperones — Thu, 16 Apr 2009 23:00:00 +0100

Authors: Sung YY, Dhaene T, Defoirdt T, Boon N, Macrae TH, Sorgeloos P, Bossier P Feeding of bacterially encapsulated heat shock proteins (Hsps) to invertebrates is a novel way to limit Vibrio infection. As an example, ingestion of Escherichia coli overproducing prokaryotic Hsps significantly improves survival of gnotobiotically cultured Artemia larvae upon challenge with pathogenic Vibrio campbellii. The relationship between Hsp accumulation and enhanced resistance to infection may involve DnaK, the prokaryotic equivalent to Hsp70, a major molecular chaperone in eukaryotic cells. In support of this proposal, heat-stressed bacterial strains LVS 2 (Bacillus sp.), LVS 3 (Aeromonas hydrophila), LVS 8 (Vibrio sp.), GR 8 (Cytophaga sp.), and GR 10 (Roseobacter sp.) were shown in this work t...

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Aeromonas spontaneous bacterial peritonitis: a highly fatal infectious disease in patients with advanced liver cirrhosis.

J Formos Med Assoc — Tue, 31 Mar 2009 23:00:00 +0100

Conclusion: Aeromonas SBP is a fatal disease, and must be included in the differential diagnosis of SBP in patients with advanced liver cirrhosis in endemic areas. PMID: 19369176 [PubMed - in process] (Source: J Formos Med Assoc)

Myxinidin, A Novel Antimicrobial Peptide from the Epidermal Mucus of Hagfish, Myxine glutinosa L.

Marine Biotechnology — Tue, 31 Mar 2009 04:00:00 +0100

This study reports the bioassay-guided fractionation and characterization of a novel antimicrobial peptide, myxinidin, from the acidic epidermal mucus extract of hagfish (Myxine glutinosa L.). Edman sequencing and mass spectrometry revealed that myxinidin consists of 12 amino acids and has a molecular mass of 1,327.68 Da. Myxinidin showed activity against a broad range of bacteria and yeast pathogens at minimum bactericidal concentration (MBC) ranging from 1.0 to 10.0 microg/mL. Screened pathogens, Salmonella enterica serovar Typhimurium C610, Escherichia coli D31, Aeromonas salmonicida A449, Yersinia ruckeri 96-4, and Listonella anguillarum 02-11 were found to be highly sensitive to myxinidin at the MBC of 1.0-2.5 microg/mL; Staphylococcus epidermis C621 and yeast (Candida albicans C627) ...

In vitro potency of doripenem tested against an international collection of rarely isolated bacterial pathogens.

Diagnostic Microbiology and Infectious Disease — Sun, 29 Mar 2009 12:33:26 +0100

In conclusion, doripenem exhibited a very wide spectrum but variable potencies against uncommonly cultured aerobic bacterial pathogens isolated in 2003 to 2007. These results confirm the potential use of this new carbapenem for broad-spectrum empiric or directed antimicrobial therapy. PMID: 19302927 [PubMed - in process] (Source: Diagnostic Microbiology and Infectious Disease)

Bacterial Enteropathogens of Neonates Admitted to an Urban Diarrhoeal Hospital in Bangladesh

Journal of Tropical Pediatrics — Thu, 26 Mar 2009 04:00:00 +0100

Data on the aetiology of diarrhoea in neonates are scarce, especially from developing countries including Bangladesh. A retrospective review of the electronic database of the Microbiology Laboratory of the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), was carried out to examine enteropathogens associated with diarrhoea in neonates. Stool specimens of the neonates on admission to the Dhaka Hospital of ICDDR,B were collected and sent to the laboratory for direct plating onto taurocholate tellurite gelatin agar, Salmonella–Shigella agar and MacConkey's agar. Stool specimens of 2511 neonates of either sex were examined. Bacterial pathogens were recovered from the stools of 699 (27.8%) of these neonates—a single bacterial pathogen from 670 neonates and ...

Isolation of Bdellovibrio as Biological Therapeutic Agents Used For the Treatment of Aeromonas hydrophila Infection in Fish

Zoonoses and Public Health — Thu, 26 Mar 2009 04:00:00 +0100

Fourteen strains of Bdellovibrio-like organisms were isolated from cultured fish ponds using Aeromonas hydrophila J-1 as host, one of them formed large plaques after 48 h of incubation at 28°C on a double layer plate, designated as Bdellovibrio C-1. The Bdellovibrio was confirmed by electron microscopy and PCR amplification of Bdellovibrio-specific 16S rDNA. The optimum temperature for the growth of BdC-1 was between 15[ndash]37°C and with optimal activity at temperatures of 25[ndash]30°C. The ability of BdC-1 to lyse A. hydrophila was similar in the pH range of 6.5 to 8.5. It can lyse 23 Gram-negative bacterial strains comprising three genera of fish pathogens and one strain of Escherichia coli but cannot lyse Gram-positive bacteria such as Bacillus subtillis and Staphylococcus aureus....

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Predicting virulence of Aeromonas isolates based on changes in transcription of c-jun and c-fos in human tissue culture cells

Journal of Applied Microbiology — Wed, 25 Mar 2009 04:00:00 +0100

Conclusions: Human cell culture results showed that c-jun and c-fos were predictive of Aeromonas virulence.Significance and Impact of the Study: An Aeromonas relative virulence scale is proposed for use in the testing of Aeromonas drinking water isolates. (Source: Journal of Applied Microbiology)

Photodynamic inactivation of Aeromonas hydrophila by cationic phthalocyanines with different hydrophobicity

FEMS Microbiology Letters — Mon, 23 Mar 2009 04:00:00 +0100

Antibacterial photodynamic therapy is a pioneering method for the inactivation of pathogenic bacteria. Four tetra alkyl-substituted cationic phthalocyanines with different hydrocarbon chains attached to the pyridyloxy group were synthesized. These photodynamic sensitizers were studied for antibacterial inactivation of a multidrug-resistant strain of Gram-negative bacterium Aeromonas hydrophila. Aeromonas species are recognized as etiological agents of a wide spectrum of diseases in humans and animals. The uptake of phthalocyanines by the bacterial cells decreased with an increase in cell density. Following the phthalocyanine solubility from hydrophilic to hydrophobic complexes, the accumulation capacity increased. Full inactivation was achieved with phthalocyanine with (methoxy)pyridyloxy ...

Quantitative detection of Helicobacter pylori in water samples by real-time PCR amplification of the cag pathogenicity island gene, cagE

Journal of Applied Microbiology — Mon, 16 Mar 2009 04:00:00 +0100

Conclusions: This real-time PCR method provides a sensitive, specific, and accurate method for the rapid quantification of H. pylori in environmental samples.Significance and Impact of the Study: The PCR diagnostic system proposed in this work, provides a suitable tool for the quantitative detection of H. pylori in environmental samples and can be useful for verifying the role of water as a potential route of its transmission. (Source: Journal of Applied Microbiology)

Development of imipenem resistance in an Aeromonas veronii biovar sobria clinical isolate recovered from a patient with cholangitis.

Journal of Medical Microbiology — Fri, 13 Mar 2009 20:16:25 +0100

Authors: Sánchez-Céspedes J, Figueras MJ, Aspiroz C, Aldea MJ, Toledo M, Alperí A, Marco F, Vila J Several imipenem-susceptible and -resistant Aeromonas veronii biovar sobria isolates with different morphologies and antimicrobial susceptibilities recovered from bile samples of a patient with cholangitis were analysed. These isolates belonged to the same clone and the imipenem-resistant strains showed overexpression of the imiS gene, encoding a chromosomal carbapenemase. These results should make clinicians aware of the possible emergence of multidrug-resistant A. veronii biovar sobria, perhaps as a consequence of previous treatment of a urinary tract infection with amoxicillin plus clavulanic acid. PMID: 19273640 [PubMed - in process] (Source: Journal of Medical Micr...

Emerging infections of the gastrointestinal tract.

Best Practice & Research. Clinical Gastroenterology — Sat, 07 Mar 2009 02:49:59 +0100

Authors: Schlenker C, Surawicz CM Infections account for significant GI morbidity and mortality worldwide. New organisms are being identified, associated with diarrhoeal illness and some with other gastrointestinal illness as well. Among GI viruses, Sapovirus is now recognised to cause diarrhoea, especially in children. A hypervirulent strain of Clostridium difficile has caused epidemics in many countries. Newly identified bacterial species that may cause diarrhoea include Campylobacter concisus, Arcobacteria, Edwardsiella tarda, Aeromonas, Plesiomonas and Laribacter. Helicobacteria are reviewed, as well as the role of gastric acid suppression in predisposing to enteric infections. PMID: 19258189 [PubMed - in process] (Source: Best Practice & Research. Clinical Gastroenterology)

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Cost-effective biostimulation strategy for wastewater decolorization using immobilized-cell systems.

Bioresource Technology — Thu, 05 Mar 2009 05:00:00 +0100

This study tended to evaluate threshold operation criteria of biostimulation for optimal biodecolorization in immobilized-cell systems (ICSs) using Porites corals as packing matrices. Indigenous Aeromonas hydrophila with high efficiency for decolorization isolated from Northeast Taiwan was used for study. As maximal treatment performance of ICS could only be achieved with maximal absorbed biomass with highest color removal capability. Maintaining optimal attached cells for cost-effective color removal efficiency inevitably required essential nutrients provided from rich media for biostimulation. With consideration of efficient cell attachment and maximal dye biodecolorization, our proposed method of "graphical reconstruction" quantitatively revealed the most economically-feasible strategy ...

[Gastroenteritis from the aspect of infectologists.]

Orvosi Hetilap — Sat, 21 Feb 2009 04:00:39 +0100

Authors: Nemes Z Gastroenteritis is a nonspecific term for various pathologic states of the gastrointestinal tract. Gastroenteritis causing pathogens are the second leading cause of morbidity and mortality worldwide. In the developed countries diarrhea is the most common reason for missing work, while in the developing world, it is a leading cause of death. Internationally, the mortality rate is 5-10 million deaths each year. "Traveller's diarrhea" is a polyetiologic common health problem of international travellers which affects travellers generally for days, but it can result in chronic postinfectious irritable bowel syndrome as well. Infectious agents usually cause acute gastroenteritis either by adherence of the intestinal mucosa, or by mucosal invasion, enterotoxin production, and...

Chimeric Enzyme Composed of Polyhydroxyalkanoate (PHA) Synthases from Ralstonia eutropha and Aeromonas caviae Enhances Production of PHAs in Recombinant Escherichia coli.

Biomacromolecules — Wed, 18 Feb 2009 05:00:00 +0100

Authors: Matsumoto K, Takase K, Yamamoto Y, Doi Y, Taguchi S Chimeric enzymes composed of polyhydroxyalkanoate (PHA) synthases from Ralstonia eutropha ( Cupriavidus necator ) (PhaC(Re)) and Aeromonas caviae (PhaC(Ac)) were constructed. PhaC(Re) is known for its potent enzymatic activity among the characterized PHA synthases. PhaC(Ac) has broad substrate specificity and synthesizes short-chain-length (SCL)/medium-chain-length (MCL) PHA. We attempted to create chimeric enzymes inheriting both of the advantageous properties. Among eight chimeras, AcRe12, with 26% of the N-terminal of PhaC(Ac) and 74% of the C-terminal of PhaC(Re), exhibited comparable P(3-hydroxybutyrate) accumulation as parental enzymes in Escherichia coli JM109. Thus, AcRe12 was applied to SCL/MCL PHA production using E...

Evaluation of a digoxigenin-labelled probe for detection of Aeromonas spp.

Letters in Applied Microbiology — Mon, 02 Feb 2009 05:00:00 +0100

An outer membrane protein-based Digoxigenin (DIG)-labelled DNA probe was developed for the specific detection of Aeromonas sp. from food/environmental/clinical samples. Dot blot reaction answered for all the Aeromonas isolates and was negative for Escherichia coli, Pseudomonas sp., Klebsiella sp., Vibrio parahaemolyticus, V. harveyi, V. alginolyticus, V. vulnificus. Edwardsiella tarda and Staphylococcus sp. As this protein is highly conserved in various Aeromonas species, the probe has the potential for use as a rapid and reliable diagnostic tool. (Source: Letters in Applied Microbiology)

A Mouse Model for Characterization of Gastrointestinal Colonization Rates Among Environmental Aeromonas Isolates.

Current Microbiology — Fri, 09 Jan 2009 05:00:00 +0100

Authors: Lye DJ The colonization rates of 10 different environmental Aeromonas isolates were determined using a novel mouse-streptomycin pretreatment method. As demonstrated, alterations to the colon flora of mice pretreated with streptomycin allowed transient colonization by bacterial species normally excluded by host competition. A novel procedure is described for determining the colonization abilities of Aeromonas isolates under these conditions. The colonization rates of A. salmonicida, A. encheleia, and A. allosaccharophila were either negative or occurred randomly at low levels with respect to concentrations of the dosage consumed by the animals. In contrast, A. hydrophila, A. veronii biovar sobria, and A. caviae exhibited relatively high rates of mouse colon tissue colonization....

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Use of whole cell culture of Aeromonas sp. as enantioselective scavenger: A facile preparation of l-amino acid derivatives in high enantiomeric excess.

Bioorganic & Medicinal Chemistry Letters — Wed, 31 Dec 2008 05:00:00 +0100

Authors: Zhang Z The bacterium Aeromonas sp. (CGMCC 2226) can enantioselectively scavenge d-isomer, making l-amino acid derivatives (AADs) in high ee. The enantioselective scavenger (ES) has shown a broad substrate scope. Eleven l-AADs, Phe derivatives substituted with methyl-, mono- and dichloro-, bromo-, and nitro-group, were produced in high ee from corresponding racemates. PMID: 19150596 [PubMed - as supplied by publisher] (Source: Bioorganic & Medicinal Chemistry Letters)

Effects of C-terminal amino acids truncation on enzyme properties of Aeromonas caviae D1 chitinase.

Archives of Microbiology — Wed, 17 Dec 2008 05:00:00 +0100

Authors: Lin FP, Chuang HH, Liu YH, Hsieh CY, Lin PW, Lin HY C-Terminal truncation mutagenesis was used to explore the functional and structural significance of the C-terminal region of Aeromonas caviae D1 chitinase (AcD1ChiA). Comparative studies between the engineered full-length AcD1ChiA and the truncated mutant (AcD1ChiAK606) included initial rate kinetics, fluorescence and circular dichroism (CD) spectrometric properties, and substrate binding and hydrolysis abilities. The overall catalytic efficiency, k (cat)/K (M), of AcD1ChiAK606 with the 4MU-(GlcNAc)(2) and the 4MU-(GlcNAc)(3) chitin substrates was 15-26% decreased. When compared with AcD1ChiA, the truncated mutant AcD1ChiAK606 maintained 80% relative substrate-binding ability and about 76% of the hydrolyzing efficiency agains...

High levels of polychlorinated biphenyls in tissues of Atlantic turtles stranded in the Canary Islands, Spain.

Chemosphere — Wed, 03 Dec 2008 05:00:00 +0100

Authors: Orós J, González-Díaz OM, Monagas P Polychlorinated biphenyls (PCBs 28, 31, 52, 101, 138, 153, 180, and 209) were measured in tissue samples (liver and fat) from 30 loggerhead turtles Caretta caretta, 1 green turtle Chelonia mydas, and 1 leatherback Dermochelys coriacea stranded on the coasts of the Canary Islands, trying to establish a possible relation between PCB concentrations and the lesions and causes of death. Tissues from these turtles contained higher levels of PCBs than those reported in turtles from other geographical regions. summation operatorPCB concentrations (1980+/-5320ngg(-1)wetwt.) in the liver of loggerheads were higher than in the adipose tissue (450+/-1700ngg(-1)wetwt.). Concentrations of PCB 209 in the liver (1200+/-3120ngg(-1)wetwt.) of l...

Characterization of Aeromonas encheleia strains isolated from aquatic environments in the Czech Republic

Letters in Applied Microbiology — Tue, 02 Dec 2008 05:00:00 +0100

Conclusions: Our results imply that Aer. encheleia strains occur in unpolluted surface as well as in underground waters and demonstrate applied methods as suitable for their identification.Significance and Impact of the Study: To our best knowledge, this is the first report of the isolation and identification of Aer. encheleia in the Czech Republic. (Source: Letters in Applied Microbiology)

Toxin Production by Aeromonas sobria in Natural Environments: River Water vs. Seawater.

Acta Med Okayama — Mon, 01 Dec 2008 05:00:00 +0100

In this study, we tested the ability of Aeromonas sobria to produce toxins in river water and seawater. First, we cultured A. sobria on skim milk agar plates supplemented with either river water (SARW) or seawater (SASW). The bacteria grew on both plates. A clear zone around the bacteria was generated in SARW. However, such a zone was not observed in SASW, suggesting that proteases were not generated in SASW. Subsequently, we cultured A. sobria in a nutrient broth supplemented with either river water (NRW) or with seawater (NSW), and examined the protease activity of their culture supernatants. The protease activity of the culture supernatant from NSW was extremely low compared to that from NRW. The immunoblotting analysis showed that serine protease (ASP) was not produced by the culture i...

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Aeromonas caviae septicemia in immunocompetent gastrointestinal carriers.

Braz J Infect Dis — Mon, 01 Dec 2008 05:00:00 +0100

Authors: Dwivedi M, Mishra A, Prasad A, Azim A, Singh RK, Baronia AK, Prasad KN, Dwivedi UN Aeromonas caviae strains have been isolated from blood and stool cultures of three immunocompetent patients, residents of Northern India, who presented with community acquired septicemia without any recent history of diarrhea. Cell culture infectivity test performed on Hep-2 cells have shown substantial degree of invasiveness in the isolated strains. This case unleashes a possibility of asymptomatic gastrointestinal carriage of such strains of A. caviae in a very large population of India, as several areas of India have very high rates of Aeromonas induced acute diarrhea/gastroenteritis (up to 13%). It needs to be appraised further in India as well as other countries having high rates of Aeromon...

In silico identification of putative drug targets from different metabolic pathways of Aeromonas hydrophila.

In Silico Biol — Sat, 29 Nov 2008 04:57:04 +0100

Authors: Sharma V, Gupta P, Dixit A Aeromonas hydrophila is a major pathogen both of aquatic and terrestrial organisms, including humans. Infection with A. hydrophila results in severe economic losses to the aquaculture industry. In humans, Aeromonas hydrophila infections are known to cause gastroenteritis and wound infections. Investigations for developing a potential vaccine for its control are underway. The availability of the complete sequence information of A. hydrophila strain ATCC 7966T genome has made it possible to carry out the in silico analysis of its genome for various aspects of its biology. Keeping in view the possible risks that A. hydrophila poses to humans, in silico analysis of the A. hydrophila genome was carried out for the identification of potential vaccine and d...

Isolation and functional characterization of neutrophil-like cells, from goldfish (Carassius auratus L.) kidney.

Developmental and Comparative Immunology — Fri, 28 Nov 2008 05:00:00 +0100

We report on the isolation, cultivation and characterization of neutrophil-like cells isolated from the goldfish kidney. Neutrophil-like cells stained positive for acid phosphatase and Sudan black, expressed MPO, and produced a dose-dependent respiratory burst response after stimulation with phorbol esters (PMA) and calciumionophore A23187 (CaI). Treatment of neutrophil-like cultures with PMA, CaI or zymosan induced a dose-dependent non-reversible degranulation of neutrophil-like cells. Goldfish neutrophil-like cells also exhibited a chemotactic response, degranulation, and respiratory burst response when exposed to the virulent fish pathogen, Aeromonas salmonicida A449. PMID: 19046985 [PubMed - as supplied by publisher] (Source: Developmental and Comparative Immunology)

Aeromonas Spp. Human Isolates Induce Apoptosis of Murine Macrophages.

Current Microbiology — Thu, 13 Nov 2008 05:00:00 +0100

Authors: Krzymińska S, Kaznowski A, Chodysz M Interactions of Aeromonas caviae, Aeromonas veronii biotype sobria, and Aeromonas hydrophila strains isolated from fecal specimens of humans with gastroenteritis on murine macrophages, J774 cells, were investigated. Analyses of cellular morphology and DNA fragmentation in phagocytes infected with these strains exhibited typical characteristic features of cells undergoing apoptosis. We observed the morphological changes, including condensation of nuclear chromatin, formation of apoptotic bodies and blebbing of cell membrane, and fragmentation of nuclear DNA into oligonucleosomal fragments. The lowest apoptotic index did not exceed 25%, whereas the highest reached 78% at 24 h and 96% at 48 h after infection. After incubation of J774 cel...

Aeromonas sobria sepsis complicated by rhabdomyolysis in an HIV-positive patient: case report and evaluation of traits associated with bacterial virulence.

International Journal of Infectious Diseases — Fri, 31 Oct 2008 04:00:00 +0100

Authors: Stano F, Brindicci G, Monno R, Rizzo C, Ghezzani F, Carbonara S, Guaglianone E, Donelli G, Monno L Human infection with Aeromonas species is uncommon and most often due to trauma with exposure to contaminated water or soil. A 43-year-old HIV- and hepatitis C virus (HCV)-infected male, after a two-week course of corticosteroid therapy for an autoimmune anemia, developed diarrhea, dermatologic manifestations and a multiple organ dysfunction syndrome, resulting in death. Although stool samples were repeatedly negative, two sets of blood cultures obtained during a single peak of fever yielded the post-mortem isolation of a Gram-negative, oxidase-positive, beta-hemolytic bacillus that was identified as Aeromonas sobria. Empiric antibiotic therapy was unsuccessful. Evaluation of the...

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Expression profiles of cytokines released in intestinal epithelial cells of the rainbow trout, Oncorhynchus mykiss, in response to bacterial infection.

Developmental and Comparative Immunology — Thu, 23 Oct 2008 04:00:00 +0100

Authors: Komatsu K, Tsutsui S, Hino K, Araki K, Yoshiura Y, Yamamoto A, Nakamura O, Watanabe T To determine whether fish intestinal epithelial cells (IECs) contribute to mucosal immunity, we established a method for isolating IECs from the rainbow trout Oncorhynchus mykiss and examined cytokine production in these cells. Components of the intestinal epithelium were released by incubation of intestinal pieces with 1mM dithiothreitol (DTT)/ethylenediamine tetraacetic acid (EDTA). The IEC-rich fraction (purity >90%; survival rate approximately 95%) was obtained by centrifugation on a 35%/40% Percoll gradient, followed by magnetic cell sorting using an anti-trout IgM antiserum. The gene expression profiles of 14 cytokines in trout IECs were investigated after culturing the cells for 6h ...

Atypical furunculosis vaccines for Atlantic cod (Gadus morhua); vaccine efficacy and antibody responses.

Vaccine — Wed, 22 Oct 2008 04:00:00 +0100

Authors: Lund V, Arnesen JA, Mikkelsen H, Gravningen K, Brown L, Schrøder MB Atypical furunculosis caused by atypical Aeromonas salmonicida, is an emerging problem in farming of Atlantic cod (Gadus morhua) in Norway, and vaccines are needed. Atypical A. salmonicida comprises a heterogeneous group of bacteria differing in surface antigens such as the A-layer protein and lipopolysaccharides (LPS). Except for one of the experimental oil-adjuvanted whole cell vaccines based on various isolates they all resulted in moderate protection. No clear correlation between vaccine efficacies and the A-protein group or LPS type of the vaccine isolates was revealed, while a correlation between efficacy and the presence of cross-reacting LPS-specific antibodies is indicated. PMID: 18951938 [Pu...

Molecular and biochemical characterization of a distinct tyrosinase involved in melanin production from Aeromonas media.

Applied Microbiology and Biotechnology — Sat, 18 Oct 2008 04:00:00 +0100

Authors: Wan X, Chai B, Liao Y, Su Y, Ye T, Shen P, Chen X A new tyrosinase was isolated from Aeromonas media strain WS and purified to homogeneity. The purified tyrosinase, termed TyrA, had a molecular mass of 58 kDa and an isoelectric point of 4.90. It exhibited optimal monophenol and diphenol oxidase activities under basic conditions (pH > 8.0). TyrA had a relatively higher affinity to diphenol substrate L: -dihydroxyphenylalanine (L: -dopa) than many other tyrosinases. EDTA or glutathione notably inhibited the enzymatic activities of TyrA, whereas Triton X-100 and SDS activated them. The full-length TyrA gene was cloned, and it encodes a 518 amino acid protein with little similarities to other reported tyrosinases. However, the purified recombinant TyrA expressed in Escherichia ...

Biocompatibility of poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) with bone marrow mesenchymal stem cells.

Acta Biomaterialia — Fri, 17 Oct 2008 04:00:00 +0100

Authors: Hu YJ, Wei X, Zhao W, Liu YS, Chen GQ As a new member of the polyhydroxyalkanoate (PHA) family, poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (PHBVHHx) was produced by recombinant Aeromonas hydrophila 4AK4. PHBVHHx showed a rougher surface and had higher hydrophobicity than the well-studied polymers poly(l-lactic acid) (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx). Human bone marrow mesenchymal stem cells (MSCs) adhered better on PHBVHHx film than on tissue culture plates (TCPs), PLA film and PHBHHx film. The cell number on the PHBVHHx film was 115% higher than that on the TCPs, 66% higher than on the PHBHHx film and 263% higher than on the PLA film (p<0.01). PHBVHHx also supported the osteogenic differentiation of MSCs. Previous stud...

Polyhydroxyalkanoates production from carbohydrates by a genetic recombinant Aeromonas sp.

Letters in Applied Microbiology — Wed, 15 Oct 2008 04:00:00 +0100

Conclusions: One of the present focuses on PHA production has been on lowering the production costs. Starch is an example of an inexpensive carbohydrate for use in industrial production of PHA. We have demonstrated that by introducing the phaCAB operon into Aeromonas sp. allowed the bacterium able to accumulated PHB using this substrate.Significance and Impact of the Study: Aeromonas spp. are able to synthesize PHA using fatty acids as carbon source. Although good robust growth results with use of starch as sole carbon source for Aeromonas, PHA synthesis does not occur. Strain KC007-R1 showed the ability to accumulate PHA in relative high amount with both carbohydrates and fatty acids as carbon source, and can be cultivated to a significant amount of cell mass and hence is a potential stra...

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Plasmid-mediated quinolone resistance in Aeromonas allosaccharophila recovered from a Swiss lake

Journal of Antimicrobial Chemotherapy — Fri, 10 Oct 2008 04:00:00 +0100

Conclusions These findings strengthen further the role of Aeromonas spp. as a reservoir of antimicrobial resistance determinants in the environment. (Source: Journal of Antimicrobial Chemotherapy)

Phylogenetic Evidence Suggests That Strains of Aeromonas hydrophila subsp. dhakensis Belong to the Species Aeromonas aquariorum sp. nov.

Current Microbiology — Tue, 07 Oct 2008 04:00:00 +0100

Authors: Martínez-Murcia A, Monera A, Alperi A, Figueras MJ, Saavedra MJ Three strains of Aeromonas hydrophila subspecies dhakensis, including the type strain, were subjected to phylogenetic analysis by sequencing gyrB, rpoD, and 16S rRNA genes and compared with all known Aeromonas species. The obtained gyrB and rpoD phylogenetic trees clearly suggested that these A. hydrophila subsp. dhakensis strains indeed belong to the species A. aquariorum. This finding may indicate that, at the time of "dhakensis" subspecies description, the strains were incorrectly identified as A. hydrophila by a polyphasic approach that included DNA-DNA hybridization. PMID: 18839248 [PubMed - as supplied by publisher] (Source: Current Microbiology)

OmpA is an adhesion factor of Aeromonas veronii, an optimistic pathogen that habituates in carp intestinal tract

Journal of Applied Microbiology — Wed, 01 Oct 2008 04:00:00 +0100

Conclusion: The OmpA homologue plays an important role in the adhesion of the Aer. veronii strain onto the surface of intestinal tract.Significance and Impact of the Study: We successfully identified an OmpA homologue to be an adhesion factor of Aer. veronii, an optimistic pathogen that habituates in carp intestinal tract. (Source: Journal of Applied Microbiology)

Expressed sequence tags (ESTs) from immune tissues of turbot (Scophthalmus maximus) challenged with pathogens

BioMed Central — Thu, 25 Sep 2008 04:00:00 +0100

Conclusion: A collection of 9256 high-quality ESTs was generated representing 3482 unique turbot sequences. A large proportion of defence/immune-related genes were identified, many of them regulated in response to specific pathogens. Putative microsatellites and SNPs were identified. These genome resources constitute the basis to develop a microarray for functional genomics studies and marker validation for genetic linkage and QTL analysis in turbot. (Source: BioMed Central)

[ARTICLES] Structure of AscE and induced burial regions in AscE and AscG upon formation of the chaperone needle-subunit complex of type III secretion system in Aeromonas hydrophila

Protein Science — Mon, 22 Sep 2008 04:00:00 +0100

In the type III secretion system (T3SS) of Aeromonas hydrophila, the putative needle complex subunit AscF requires both putative chaperones AscE and AscG for formation of a ternary complex to avoid premature assembly. Here we report the crystal structure of AscE at 2.7 Å resolution and the mapping of buried regions of AscE, AscG, and AscF in the AscEG and AscEFG complexes using limited protease digestion. The dimeric AscE is comprised of two helix–turn–helix monomers packed in an antiparallel fashion. The N-terminal 13 residues of AscE are buried only upon binding with AscG, but this region is found to be nonessential for the interaction. AscE functions as a monomer and can be coexpressed with AscG or with both AscG and AscF to form soluble complexes. The AscE binding reg...

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The genome of Aeromonas salmonicida subsp. salmonicida A449: insights into the evolution of a fish pathogen

BMC Genomics - Latest articles — Thu, 18 Sep 2008 04:00:00 +0100

Conclusions: Relative to the A. hydrophila ATCC 7966T genome, the A. salmonicida subsp. salmonicida genome has acquired multiple mobile genetic elements, undergone substantial rearrangement and developed a significant number of pseudogenes. These changes appear to be a consequence of adaptation to a specific host, salmonid fish, and provide insights into the mechanisms used by the bacterium for infection and avoidance of host defence systems. (Source: BMC Genomics - Latest articles)

Case Reports: Fatal Necrotizing Fasciitis Caused by Aeromonas sobria in Two Diabetic Patients.

Clinical Orthopaedics and Related Research — Thu, 18 Sep 2008 04:00:00 +0100

We report two rare cases of Aeromonas sobria necrotizing fasciitis with sepsis in patients with diabetes. In both cases, immediate fasciotomy was performed and appropriate empiric antimicrobial therapy and intensive care were administered. However, the two patients died on Day 2 and Day 11, respectively, after admission as a result of multiple organ failure. When patients present with a rapid onset of skin necrosis and progressive sepsis, an Aeromonas sobria infection or Vibrio infection should be considered in the differential diagnosis. PMID: 18800212 [PubMed - as supplied by publisher] (Source: Clinical Orthopaedics and Related Research)

Production of monoclonal antibodies specific to major outer membrane protein of Edwardsiella tarda.

Comparative immunology, microbiology and infectious diseases. — Thu, 18 Sep 2008 04:00:00 +0100

Authors: Kumar G, Rathore G, Sengupta U, Kapoor D, Lakra WS Edwardsiella tarda is an important cause for hemorrhagic septicemia in fish and gastro and extra-intestinal infections in humans. Monoclonal antibodies (MAbs) were produced against outer membrane proteins (OMPs) of E. tarda ET-7, isolated from diseased snakehead (Ophiocephalus punctatus). Two stable hybridoma clones, designated as 3F10 and 2C3 MAbs were found to be potentially specific for E. tarda by indirect enzyme linked immunosorbent assay (ELISA). These MAbs recognized major immunogenic OMP band at 44kDa in Western blotting. Both MAbs belonged to the IgG1 isotype and recognized different epitopes of OMP as seen by competitive ELISA. These MAbs strongly reacted with all 17 isolates of E. tarda used in our study by indirect...

In vitro evaluation on adherence and antimicrobial properties of a candidate probiotic Clostridium butyricum CB2 for farmed fish

Journal of Applied Microbiology — Mon, 15 Sep 2008 04:00:00 +0100

Conclusions: The strain Cl. butyricum CB2 could be used as potential probiotic to inhibit pathogens growth and prevent their colonization in fish intestinal tract.Significance and Impact of the Study: This study revealed the antimicrobial and adhesion characteristic of Cl. butyricum CB2 which was selected as the potential probiotic to farmed fish. (Source: Journal of Applied Microbiology)