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BMC Microbiology Aug 2017Aeromonas spp. are gram-negative bacteria that can cause a variety of infections in both humans and animals and play a controversial role in diarrhea outbreaks. Our aim...
BACKGROUND
Aeromonas spp. are gram-negative bacteria that can cause a variety of infections in both humans and animals and play a controversial role in diarrhea outbreaks. Our aim was to identify clinical and environmental Aeromonas isolates associated with a cholera outbreak in a northeast county of Brazil at the species level. We also aimed to determine the genetic structure of the bacterial population and the virulence potential of the Aeromonas isolates.
METHODS AND RESULTS
Analysis based on concatenated sequences of the 16S rRNA and gyrB genes suggested the classification of the 119 isolates studied into the following species: A. caviae (66.9%), A. veronii (15.3%), A. aquariorum (9.3%), A. trota (3.4%), A. hydrophila (3.4%) and A. jandaei (1.7%). One isolate did not fit any Aeromonas species assessed, which might indicate a new species. The haplotype network based on 16S rRNA gene sequences identified 59 groups among the 119 isolates and 26 reference strains, and it clustered almost all A. caviae isolates into the same group. The analysis of the frequency patterns of seven virulence-associated genes (alt, ast, hlyA, aerA, exu, lip, flaA/B) revealed 29 virulence patterns composed of one to seven genes. All the isolates harbored at least one gene, and three of them harbored all seven virulence genes.
CONCLUSION
The results emphasize the need to improve local water supply and maintain close monitoring of possible bacterial contamination in the drinking water.
Topics: Aeromonas; Bacterial Proteins; Bacterial Typing Techniques; Base Sequence; Brazil; Cluster Analysis; DNA Gyrase; DNA, Bacterial; Diarrhea; Disease Outbreaks; Feces; Genes, Bacterial; Genetic Variation; Gram-Negative Bacterial Infections; Humans; Phylogeny; RNA, Ribosomal, 16S; Virulence; Water Microbiology
PubMed: 28821241
DOI: 10.1186/s12866-017-1089-0 -
Biomedical and Environmental Sciences :... Jun 2021This study was performed to compare the genetic diversity, virulence, and antimicrobial resistance of strains isolated from patients and healthy individuals. (Comparative Study)
Comparative Study
OBJECTIVE
This study was performed to compare the genetic diversity, virulence, and antimicrobial resistance of strains isolated from patients and healthy individuals.
METHODS
A total of 38 clinical strains and 19 strains from healthy individuals were isolated from the samples collected in Ma'anshan City, Anhui Province. Their taxonomy was investigated using concatenated - sequences, and their resistance to 12 antibiotics was evaluated. The pathogenicity of these strains was examined through beta-hemolysis, protease activity, and virulence gene assays.
RESULTS
The 57 strains were divided into 55 sequence types. Of these types, 21 were novel, suggesting that their genetic diversity was high. These isolates could be divided into 7 species, and the positive rates of beta-hemolysis and protease activity were 49.1% and 73.7%, respectively. The detection rate of clinical patients in terms of beta-hemolysis and protease activity was higher than that of healthy individuals. Among the four most common strains, had the highest detection rate of virulence genes. The multidrug resistance rate of the clinical isolates was much higher than that of the strains isolated from healthy individuals.
CONCLUSIONS
The taxonomy, virulence properties, and antibiotic resistance of isolates from patients differ from those of the isolates from healthy individuals.
Topics: Aeromonas; Case-Control Studies; Drug Resistance, Bacterial; Genetic Variation; Humans; Virulence Factors
PubMed: 34284853
DOI: 10.3967/bes2021.062 -
BMC Infectious Diseases Feb 2019Clinical characteristics (taxonomy, virulence genes and antimicrobial resistance ) of Aeromonas in isolated from extra-intestinal and intestinal infections were...
BACKGROUND
Clinical characteristics (taxonomy, virulence genes and antimicrobial resistance ) of Aeromonas in isolated from extra-intestinal and intestinal infections were investigated to describe epidemiology, associated virulence factors and optimal therapy options.
METHODS
Clinical samples (n = 115) of Aeromonas were collected from a general hospital in Beijing between the period 2015 and 2017. Taxonomy was investigate by Multilocus phylogenetic analysis (MLPA), 10 putative virulence factors by use of polymerase chain reaction (PCR) and antimicrobial resistance to 15 antibiotics by use of the microbroth dilution method.
RESULTS
The most common species of Aeromonas detected in samples of intestinal tract included; A. caviae (43.9%), A. veronii (35.7%), and A. dhakensis (12.2%). Prevalent species of Aeromonas collected from extra-intestinal infections included; A. hydrophila (29.4%), A. caviae (29.4%), and A. dhakensis (23.5%). A. hydrophila were detected in 1% of stool samples and 29.4% (5/17) of extra-intestinal infections. A. hydrophila strains in extra-intestinal infections were related to malignancy. The most common medical conditions among patients with Aeromonas infections included malignancy and liver-transplant related cholecystitis. Multiple drug resistance (MDR) was prevalent in extra-intestinal isolates (82.3%, 14/17) and was greater than the prevalence in intestinal isolates (30.6%, 30/98) (P < 0.05). Resistant rates of extra-intestinal isolates were 70.6, 35.3, 23.5 and 5.9% for ceftriaxone, ciprofloxacin, gentamicin and imipenem, respectively, and were higher than found in previous studies. Despite differences in the number and type of virulence genes among samples of Aeromonas, no significant correlation was found between invasion and virulent genes in intestinal or extra-intestinal infections.
CONCLUSIONS
Overall results of this study support a role for Aeromonas spp. as a potential causative infectious agent of gastroenteritis, and malignancy, liver cirrhosis, post liver transplantation in immunocompromised patients. A. hydrophila was more prevalent in samples of extra-intestinal infections when compared to samples of intestinal infections, and was especially prominent in samples of patients presenting with malignancy. Aeromonas isolates from extra-intestinal samples had high rates of drug resistance but 3rd generation cephalosporins, fluoroquinolones and aminoglycosides remain as options to treat severe diarrhea. However, increasing MDR of extra-intestinal infection samples warrants monitoring.
Topics: Adolescent; Adult; Aeromonas; Anti-Bacterial Agents; Bacterial Typing Techniques; Child; Child, Preschool; China; Drug Resistance, Bacterial; Female; Gastroenteritis; Gram-Negative Bacterial Infections; Humans; Immunocompromised Host; Intestinal Diseases; Intraabdominal Infections; Male; Microbial Sensitivity Tests; Middle Aged; Multilocus Sequence Typing; Phylogeny; Prevalence; Virulence; Virulence Factors; Young Adult
PubMed: 30764764
DOI: 10.1186/s12879-019-3766-0 -
Applied and Environmental Microbiology Feb 2014Members of the genus Aeromonas are ubiquitous in nature and have increasingly been implicated in numerous diseases of humans and other animal taxa. Although some species...
Members of the genus Aeromonas are ubiquitous in nature and have increasingly been implicated in numerous diseases of humans and other animal taxa. Although some species of aeromonads are human pathogens, their presence, density, and relative abundance are rarely considered in assessing water quality. The objectives of this study were to identify Aeromonas species within Lake Erie, determine their antibiotic resistance patterns, and assess their potential pathogenicity. Aeromonas strains were isolated from Lake Erie water by use of Aeromonas selective agar with and without tetracycline and ciprofloxacin. All isolates were analyzed for hemolytic ability and cytotoxicity against human epithelial cells and were identified to the species level by using 16S rRNA gene restriction fragment length polymorphisms and phylogenetic analysis based on gyrB gene sequences. A molecular virulence profile was identified for each isolate, using multiplex PCR analysis of six virulence genes. We demonstrated that Aeromonas comprised 16% of all culturable bacteria from Lake Erie. Among 119 Aeromonas isolates, six species were identified, though only two species (Aeromonas hydrophila and A. veronii) predominated among tetracycline- and ciprofloxacin-resistant isolates. Additionally, both of these species demonstrated pathogenic phenotypes in vitro. Virulence gene profiles demonstrated a high prevalence of aerolysin and serine protease genes among A. hydrophila and A. veronii isolates, a genetic profile which corresponded with pathogenic phenotypes. Together, our findings demonstrate increased antibiotic resistance among potentially pathogenic strains of aeromonads, illustrating an emerging potential health concern.
Topics: Aeromonas; Anti-Bacterial Agents; Cell Survival; Ciprofloxacin; DNA Gyrase; Drug Resistance, Bacterial; Epithelial Cells; Hemolysis; Lakes; Phylogeny; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Tetracycline; Virulence Factors
PubMed: 24242249
DOI: 10.1128/AEM.03645-13 -
Frontiers in Immunology 2022are autochthonous bacteria of aquatic environments that are considered to be emerging pathogens to humans, producing diarrhea, bacteremia, and wound infections. Genetic...
are autochthonous bacteria of aquatic environments that are considered to be emerging pathogens to humans, producing diarrhea, bacteremia, and wound infections. Genetic identification shows that 95.4% of the strains associated with clinical cases correspond to the species (37.26%), (23.49%), (21.54%), and (13.07%). However, few studies have investigated the human immune response against some spp. such as , , and . The present study aimed to increase the knowledge about the innate human immune response against six species, using, for the first time, an infection model with the monocytic human cell line THP-1, and to evaluate the intracellular survival, the cell damage, and the expression of 11 immune-related genes (, , , , , , , , , , and ). Transcriptional analysis showed an upregulated expression of a variety of the monocytic immune-related genes, with a variable response depending upon the species. The species that produced the highest cell damage, independently of the strain origin, coincidentally induced a higher expression of immune-related genes and corresponded to the more prevalent clinical species , , and . Additionally, monocytic cells showed an overexpression of the apoptotic and pyroptotic genes involved in cell death after , , and infection. However, the apoptosis route seemed to be the only way of producing cell damage and death in the case of the species and , while apparently only used the pyroptosis route.
Topics: Aeromonas; Aeromonas hydrophila; Cell Line; Gram-Negative Bacterial Infections; Humans; Immunity
PubMed: 35874671
DOI: 10.3389/fimmu.2022.875689 -
Journal of Agricultural and Food... Nov 2023Lactic acid bacteria (LAB) were screened from (red sea bass), and their antimicrobial activities were evaluated against two species isolated from the , namely, (AV)...
Lactic acid bacteria (LAB) were screened from (red sea bass), and their antimicrobial activities were evaluated against two species isolated from the , namely, (AV) and (AJ). Three LAB isolates, MU8 (EF_8), MU2 (EFL_2), and MU9 (EFL_9), were found to inhibit both AV and AJ; however, their cell-free supernatant (CFS) did not do so. Interestingly, bacteriocin-like substances (BLS) induced by cocultures of EF_8 with AV exhibited the highest antimicrobial activity against both sp. The size of BLS was less than 1.0 kDa; the purified BLS were susceptible to proteinase K digestion, indicating that they are peptides. BLS contained 13 identified peptides derived from as determined by liquid chromatography-tandem mass spectrometry. Cocultures of Gram-positive-producing and -inducing LAB strains have been used to increase bacteriocin yields. To our knowledge, this is the first report describing inducible BLS produced by cocultures of Gram-positive-producing and Gram-negative-inducing strains.
Topics: Enterococcus faecium; Bacteriocins; Aeromonas veronii; Coculture Techniques; Aeromonas; Peptides; Anti-Infective Agents; Anti-Bacterial Agents
PubMed: 37779478
DOI: 10.1021/acs.jafc.3c04019 -
The Journal of Veterinary Medical... May 2017To investigate the potential enterotoxicity and antimicrobial resistance of aeromonads from pet turtles as a risk for human infection, one hundred and two Aeromonas spp....
To investigate the potential enterotoxicity and antimicrobial resistance of aeromonads from pet turtles as a risk for human infection, one hundred and two Aeromonas spp. were isolated from the feces, skin and rearing environments of pet turtles and identified by biochemical and gyrB sequence analyses. Aeromonas enteropelogenes was the predominant species among the isolates (52.9%) followed by A. hydrophila (32.4%), A. dharkensis (5.9%), A. veronii (4.9%) and A. caviae (3.9%). Their potential enterotoxicities were evaluated by PCR assays for detecting genes encoding cytotoxic enterotoxin (act) and two cytotonic enterotoxins (alt and ast). 75.8% of A. hydrophila isolates exhibited the act/alt/ast genotype, whereas 94.4% of A. enteropelogenes isolates were determined to be act/alt/ast. In an antimicrobial susceptibility test, most isolates were susceptible to all tested antibiotics except amoxicillin, ampicillin, cephalothin, chloramphenicol and tetracycline. Non-susceptible isolates to penicillins (ampicillin and amoxicillin) and fluoroquinolones (ciprofloxacin and norfloxacin) were frequently observed among the A. enteropelogenes isolates. Few isolates were resistant to imipenem, amikacin, ceftriaxone and cefotaxime. Collectively, these results suggest that pet turtles may pose a public health risk of infection by enterotoxigenic and antimicrobial resistant Aeromonas strains.
Topics: Aeromonas; Aeromonas hydrophila; Animals; Anti-Bacterial Agents; Enterotoxins; Environmental Microbiology; Feces; Genes, Bacterial; Gram-Negative Bacterial Infections; Microbial Sensitivity Tests; Turtles
PubMed: 28392536
DOI: 10.1292/jvms.16-0493 -
Gut Microbes 2012Gastrointestinal microbiomes play important roles in the health and nutrition of animals and humans. The medicinal leech, Hirudo verbana, serves as a powerful model for... (Review)
Review
Gastrointestinal microbiomes play important roles in the health and nutrition of animals and humans. The medicinal leech, Hirudo verbana, serves as a powerful model for the study of microbial symbioses of the gut, due to its naturally limited microbiome compared with other popular models, the ability to cultivate the most abundant microbes, and genetically manipulate one of them, Aeromonas veronii. This review covers the relevance and application of leeches in modern medicine as well as recent discoveries detailing the nature of the gut microbiome. Additionally, the dual life-style of A. veronii allows one to do direct comparisons between colonization factors for beneficial and pathogenic associations, and relevant findings are detailed with respect to their role within the host and pathogenicity to other animals.
Topics: Aeromonas; Animals; Gastrointestinal Tract; Leeches; Symbiosis
PubMed: 22572874
DOI: 10.4161/gmic.20227 -
Dynamics of Aeromonas hydrophila, Aeromonas sobria, and Aeromonas caviae in a sewage treatment pond.Applied and Environmental Microbiology Jul 1990The spatiotemporal dynamics of Aeromonas spp. and fecal coliforms in the sewage treatment ponds of an urban wastewater center were studied after 20 months of sampling...
The spatiotemporal dynamics of Aeromonas spp. and fecal coliforms in the sewage treatment ponds of an urban wastewater center were studied after 20 months of sampling from five stations in these ponds. Isolation and identification of 247 Aeromonas strains were undertaken over four seasons at the inflow and outflow of this pond system. The hemolytic activity of these strains was determined. The Aeromonas spp. and the fecal coliform distributions showed seasonal cycles, the amplitude of which increased at distances further from the wastewater source, so that in the last pond there was an inversion of the Aeromonas spp. cycle in comparison with that of fecal coliforms. The main patterns in these cycles occurred simultaneously at all stations, indicating control of these bacterial populations by seasonal factors (temperature, solar radiation, phytoplankton), the effects of which were different on each bacterial group. The analysis of the Aeromonas spp. population structure showed that, regardless of the season, Aeromonas caviae was the dominant species at the pond system inflow. However at the outflow the Aeromonas spp. population was dominated by A. caviae in winter, whereas Aeromonas sobria was the dominant species in the treated effluent from spring to fall. Among the Aeromonas hydrophila and A. sobria strains, 100% produced hemolysin; whereas among the A. caviae strains, 96% were nonhemolytic.
Topics: Aeromonas; Enterobacteriaceae; Hemolysin Proteins; Seasons; Sewage; Temperature; Virulence; Waste Disposal, Fluid; Water Microbiology
PubMed: 2389929
DOI: 10.1128/aem.56.7.1999-2006.1990 -
Diseases of Aquatic Organisms Feb 1998Bacterial strains of Aeromonas salmonicida included in the recognized subsp. acromogenes, subsp. masoucida, and subsp. smithia in addition to the large number of strains... (Review)
Review
Bacterial strains of Aeromonas salmonicida included in the recognized subsp. acromogenes, subsp. masoucida, and subsp. smithia in addition to the large number of strains not included in any of the described subspecies are referred to as atypical A. salmonicida. The atypical strains form a very heterogeneous group with respect to biochemical characteristics, growth conditions, and production of extracellular proteasess. Consequently, the present taxonomy of the species A. salmonicida is rather ambiguous. Atypical A. salmonicida has been isolated from a wide range of cultivated and wild fish species, non-salmonids as well as salmonids, inhabiting fresh water, brackish water and marine environments in northern and central Europe, South Africa, North America, Japan and Australia. In non-salmonid fish species, infections with atypical strains often manifest themselves as superficial skin ulcerations. The best known diseases associated with atypical A. salmonicida are carp Cyprinus carpio erythrodermatitis, goldfish Carassius auratus ulcer disease, and ulcer disease of flounder Platichthys flesus, but atypical strains are apparently involved in more disease outbreaks than previously suspected. Macroscopical and microscopical studies of ulcerated fish indicate internal organs are infrequently invaded by atypical A. salmonicida. This view is supported by the fact that atypical strains are irregularly isolated from visceral organs of ulcerated fish. High mortality caused by atypical A. salmonicida has been observed in populations of wild non-salmonids and farmed salmonids, although the association between the mortality in the wild fish stocks and atypical A. salmonicida has not always been properly assessed. In injection experiments the pathogenicity of the atypical strains examined showed large variation. An extacellular A-layer has been detected in different atypical strains, but virulence mechanisms different from those described for (typical) A. salmonicida subsp. salmonicida, for example an extracellular metallo-protease and a different iron utilization mechanism, have been described. Limited information is available about the ecology, spread and survival of atypical strains in water. The commonly used therapeutic methods for the control of diseases in farmed fish caused by atypical A. salmonicida are generally effective against the atypical strains. Resistance to different antibiotics and transferable plasmid encoding multiple drug resistance have been observed in atpical A. salmonicida. Studies aimed at producing a vaccine against atypical strains are in progress.
Topics: Aeromonas; Animals; Fish Diseases; Fisheries; Fishes; Gram-Negative Bacterial Infections; Salmonidae; Virulence
PubMed: 9696626
DOI: 10.3354/dao032049