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Canadian Medical Association Journal Apr 1979Aeromonas hydrophila has for some time been regarded as an opportunistic pathogen in hosts with impaired local or general defence mechanisms. Infections in such... (Review)
Review
Aeromonas hydrophila has for some time been regarded as an opportunistic pathogen in hosts with impaired local or general defence mechanisms. Infections in such individuals are generally severe. The organism is also being isolated with increasing frequency throughout the world from a variety of focal and systemic infections of varying severity in persons that are apparently immunologically normal. Most commonly it causes acute diarrheal disease by producing an enterotoxin. Thus the organism appears to have greater clinical significance that was hitherto suspected. The organism has been infrequently reported from humans in Canada, but its correct laboratory identification, together with increased awareness that it can contribute to illness, will undoubtedly lead to more reports of its isolation in Canada.
Topics: Aeromonas; Bacterial Infections; Bacteriological Techniques; Cytotoxins; Diarrhea; Drug Resistance, Microbial; Enterotoxins; Gastroenteritis; Gastrointestinal Diseases; Humans; In Vitro Techniques; Microbial Sensitivity Tests; Virulence; Wound Infection
PubMed: 373876
DOI: No ID Found -
Brazilian Journal of Microbiology :... Sep 2020Aeromonas dhakensis is an emergent human pathogen with medical importance. This study was aimed to determine the sequence types (STs), genetic diversity, and...
Aeromonas dhakensis is an emergent human pathogen with medical importance. This study was aimed to determine the sequence types (STs), genetic diversity, and phylogenetic relationships of different clinical sources of 47 A. dhakensis from Malaysia using multilocus sequence typing (MLST), goeBURST, and phylogenetic analyses. The analysis of a concatenated six-gene tree with a nucleotide length of 2994 bp based on six housekeeping genes (gyrB, groL, gltA, metG, ppsA, and recA) and independent analyses of single gene fragments was performed. MLST was able to group 47 A. dhakensis from our collection into 36 STs in which 34 STs are novel STs. The most abundant ST521 consisted of five strains from peritoneal fluid and two strains from stools. Comparison of 62 global A. dhakensis was carried out via goeBURST; 94.4% (34/36) of the identified STs are novel and unique in Malaysia. Two STs (111 and 541) were grouped into clonal complexes among our strains and 32 STs occurred as singletons. Single-gene phylogenetic trees showed varying topologies; groL and rpoD grouped all A. dhakensis into a tight-cluster with bootstrap values of 100% and 99%, respectively. A poor phylogenetic resolution encountered in single-gene analyses was buffered by the multilocus phylogenetic tree that offered high discriminatory power (bootstrap value = 100%) in resolving all A. dhakensis from A. hydrophila and delineating the relationship among other taxa. Genetic diversity analysis showed groL as the most conserved gene and ppsA as the most variable gene. This study revealed novel STs and high genetic diversity among clinical A. dhakensis from Malaysia.
Topics: Aeromonas; DNA, Bacterial; Genes, Bacterial; Genes, Essential; Genetic Variation; Gram-Negative Bacterial Infections; Humans; Malaysia; Phylogeny; Sequence Analysis, DNA
PubMed: 32067209
DOI: 10.1007/s42770-020-00239-8 -
Environmental Microbiology Sep 2012We evaluated the population structure and temporal dynamics of the dominant community members within sewage influent from two wastewater treatment plants (WWTPs) in...
We evaluated the population structure and temporal dynamics of the dominant community members within sewage influent from two wastewater treatment plants (WWTPs) in Milwaukee, WI. We generated > 1.1 M bacterial pyrotag sequences from the V6 hypervariable region of 16S rRNA genes from 38 influent samples and two samples taken upstream in the sanitary sewer system. Only a small fraction of pyrotags from influent samples (∼ 15%) matched sequences from human faecal samples. The faecal components of the sewage samples included enriched pyrotag populations from Lactococcus and Enterobacteriaceae relative to their fractional representation in human faecal samples. In contrast to the large number of distinct pyrotags that represent faecal bacteria such as Lachnospiraceae and Bacteroides, only one or two unique V6 sequences represented Acinetobacter, Aeromonas and Trichococcus, which collectively account for nearly 35% of the total sewage community. Two dominant Acinetobacter V6 pyrotags (designated Acineto tag 1 and Acineto tag 2) fluctuated inversely with a seasonal pattern over a 3-year period, suggesting two distinct Acinetobacter populations respond differently to ecological forcings in the system. A single nucleotide change in the V6 pyrotags accounted for the difference in these populations and corresponded to two phylogenetically distinct clades based on full-length sequences. Analysis of wavelet functions, derived from a mathematical model of temporal fluctuations, demonstrated that other abundant sewer associated populations including Trichococcus and Aeromonas had temporal patterns similar to either Acineto tag 1 or Acineto tag 2. Populations with related temporal fluctuations were found to significantly correlate with the same WWTP variables (5-day BOD, flow, ammonia, total phosphorous and suspended solids). These findings illustrate that small differences in V6 sequences can represent phylogenetically and ecologically distinct taxa. This work provides insight into microbial community composition and dynamics within the defined environment of urban sewer infrastructure.
Topics: Acinetobacter; Aeromonas; Bacteria; Bacterial Physiological Phenomena; Biodiversity; Carnobacteriaceae; Phylogeny; RNA, Ribosomal, 16S; Seasons; Sewage; Urban Population
PubMed: 22524675
DOI: 10.1111/j.1462-2920.2012.02757.x -
Brazilian Journal of Microbiology :... Mar 2021Aeromonas are bacteria broadly spread in the environment, particularly in aquatic habitats and can induce human infections. Several virulence factors have been described... (Comparative Study)
Comparative Study
Aeromonas are bacteria broadly spread in the environment, particularly in aquatic habitats and can induce human infections. Several virulence factors have been described associated with bacterial pathogenicity, such as the Type VI Secretion System (T6SS). This system translocates effector proteins into target cells through a bacteriophage-like contractile structure encoded by tss genes. Here, a total of 446 Aeromonas genome sequences were screened for T6SS and the proteins subjected to in silico analysis. The T6SS-encoding locus was detected in 243 genomes and its genes are encoded in a cluster containing 13 core and 5 accessory genes, in highly conserved synteny. The amino acid residues identity of T6SS proteins ranges from 78 to 98.8%. In most strains, a pair of tssD and tssI is located upstream the cluster (tssD-2, tssI-2) and another pair was detected distant from the cluster (tssD-1, tssI-1). Significant variability was seen in TssI (VgrG) C-terminal region, which was sorted in four groups based on its sequence length and protein domains. TssI containing ADP-ribosyltransferase domain are associated exclusively with TssI-1, while genes coding proteins carrying DUF4123 (a conserved domain of unknown function) were observed downstream tssI-1 or tssI-2 and escort of possible effector proteins. Genes coding proteins containing DUF1910 and DUF1911 domains were located only downstream tssI-2 and might represent a pair of toxin/immunity proteins. Nearly all strains display downstream tssI-3, that codes for a lysozyme family domain protein. These data reveal that Aeromonas T6SS cluster synteny is conserved and the low identity observed for some genes might be due to species heterogeneity or its niche/functionality.
Topics: Aeromonas; Bacterial Proteins; Computer Simulation; Genome, Bacterial; Multigene Family; Sequence Analysis, Protein; Type VI Secretion Systems; Virulence Factors
PubMed: 33410103
DOI: 10.1007/s42770-020-00405-y -
BMC Veterinary Research Jan 2024Aeromonas species are one of the most important etiologies of diseases in fish farms, leading to clinical manifestation and mortality and are associated with public...
BACKGROUND
Aeromonas species are one of the most important etiologies of diseases in fish farms, leading to clinical manifestation and mortality and are associated with public health risks. This study aimed to investigate the prevalence, phenotypic and molecular characteristics of Aeromonas species isolated from farmed Clarias gariepinus using 16 S rRNA sequencing. Additionally, their antibiogram and multiple antibiotic resistance index were determined using a disc diffusion test.
RESULTS
A total of 230 Aeromonas strains were isolated from Clarias gariepinus with 40.9% obtained from diseased fish, and 25% isolated from apparently healthy ones. Five different species including Aeromonas caviae, Aeromonas veronii, Aeromonas hydrophila, Aeromonas dhakensis and Aeromonas enteropelogenes were fully identified and genetically characterized. Based on the available literature, this is the first report of Aeromonas enteropelogenes from the study area. The phylogenetic analysis showed genetic heterogeneity and distance within the species and the reference strains. The multiple resistant Aeromonas species were susceptible to ciprofloxacin, gentamycin, and florfenicol. The Aeromonas species' multiple antibiotic resistance index values varied between 0.20 and 0.80 and were isolated from the farms where antibiotics were intensively used.
CONCLUSIONS
The diversity of multidrug-resistant Aeromonas species isolated from fish farms is a major threat to fish production giving us more understanding of epidemiology and the multidrug Aeromonas species with a MAR index of greater than 0.2 were isolated from farms where antibiotic use was widespread. As a result, a considerably increased danger of multiple antibiotic resistance spreading to the fish culture environment may impact aquaculture production. Hence there is a need for appropriate and monitored drug usage.
Topics: Animals; Catfishes; Phylogeny; Aeromonas; Drug Resistance, Microbial; Anti-Bacterial Agents
PubMed: 38184574
DOI: 10.1186/s12917-023-03860-5 -
Revista Chilena de Infectologia :... Apr 2011
Topics: Aeromonas; Animals; Humans
PubMed: 21720695
DOI: No ID Found -
BMC Microbiology Oct 2015Treated wastewater effluent has been found to contain high levels of contaminants, including disease-causing bacteria such as Listeria and Aeromonas species. The aim of...
Antimicrobial resistance and virulence signatures of Listeria and Aeromonas species recovered from treated wastewater effluent and receiving surface water in Durban, South Africa.
BACKGROUND
Treated wastewater effluent has been found to contain high levels of contaminants, including disease-causing bacteria such as Listeria and Aeromonas species. The aim of this study was to evaluate the antimicrobial resistance and virulence signatures of Listeria and Aeromonas spp. recovered from treated effluents of two wastewater treatment plants and receiving rivers in Durban, South Africa.
METHODS
A total of 100 Aeromonas spp. and 78 Listeria spp. were positively identified based on biochemical tests and PCR detection of DNA region conserved in these genera. The antimicrobial resistance profiles of the isolates were determined using Kirby Bauer disc diffusion assay. The presence of important virulence genes were detected via PCR, while other virulence determinants; protease, gelatinase and haemolysin were detected using standard assays.
RESULTS
Highest resistance was observed against penicillin, erythromycin and nalidixic acid, with all 78 (100%) tested Listeria spp displaying resistance, followed by ampicillin (83.33%), trimethoprim (67.95%), nitrofurantoin (64.10%) and cephalosporin (60.26%). Among Aeromonas spp., the highest resistance (100%) was observed against ampicillin, penicillin, vancomycin, clindamycin and fusidic acid, followed by cephalosporin (82%), and erythromycin (58%), with 56% of the isolates found to be resistant to naladixic acid and trimethoprim. Among Listeria spp., 26.92% were found to contain virulence genes, with 14.10, 5.12 and 21% harbouring the actA, plcA and iap genes, respectively. Of the 100 tested Aeromonas spp., 52% harboured the aerolysin (aer) virulence associated gene, while lipase (lip) virulence associated gene was also detected in 68% of the tested Aeromonas spp.
CONCLUSIONS
The presence of these organisms in effluents samples following conventional wastewater treatment is worrisome as this could lead to major environmental and human health problems. This emphasizes the need for constant evaluation of the wastewater treatment effluents to ensure compliance to set guidelines.
Topics: Aeromonas; Anti-Bacterial Agents; Bacteriological Techniques; Disk Diffusion Antimicrobial Tests; Drug Resistance, Bacterial; Humans; Listeria; Polymerase Chain Reaction; South Africa; Virulence Factors; Wastewater; Water Purification
PubMed: 26498595
DOI: 10.1186/s12866-015-0570-x -
Journal of Clinical Microbiology May 1991Between January 1988 and December 1989 Aeromonas species were isolated from 45 (1.8%) of 2,480 patients with acute gastroenteritis. No other bacterial enteric pathogens...
Between January 1988 and December 1989 Aeromonas species were isolated from 45 (1.8%) of 2,480 patients with acute gastroenteritis. No other bacterial enteric pathogens were found in any of these 45 patients. Of the 45 Aeromonas isolates, 35 strains (77.8%) were Aeromonas hydrophila, 7 (15.5%) were Aeromonas sobria, and 3 (6.7%) were Aeromonas caviae. Most of the patients were under 5 years of age. No bacterial enteric pathogens, including Aeromonas species, were isolated from 512 age- and sex-matched control subjects. Examination of the Aeromonas isolates for exotoxin production (enterotoxin and hemolysin) indicated that all strains, irrespective of species, were enterotoxin positive (rabbit ileal loop model) and hemolysin positive (rabbit erythrocyte model). These results suggest that Aeromonas species are potential enteric pathogens in our geographical region.
Topics: Aeromonas; Child, Preschool; Diarrhea; Enterotoxins; Gastroenteritis; Hemolysin Proteins; Humans; Species Specificity
PubMed: 2056050
DOI: 10.1128/jcm.29.5.853-856.1991 -
FEMS Immunology and Medical Microbiology Feb 2002One hundred and ninety four Aeromonas isolates (99 from food and 95 from clinical sources) were analyzed as to the species involved and the toxins produced. Of the...
One hundred and ninety four Aeromonas isolates (99 from food and 95 from clinical sources) were analyzed as to the species involved and the toxins produced. Of the clinical isolates of Aeromonas, 29.4% were enterotoxigenic, 43.1% were hemolytic and 89% were cytotoxigenic. Among the food isolates, 18.2% were enterotoxigenic, 17.1% were hemolytic and 72.7% were cytotoxigenic. Aeromonas sobria and Aeromonas veronii produced more enterotoxin and cytotoxin than the other isolates, whereas A. veronii and Aeromonas salmonicida produced cell-free hemolysin. Most of the isolates produced cytotoxins (81%) active on Vero (green monkey kidney) and Chinese hamster ovary cells, but only the culture supernatant of A. sobria produced vacuolation in these cell lines.
Topics: Aeromonas; Animals; Brazil; CHO Cells; Chlorocebus aethiops; Cricetinae; Cytotoxins; Enterotoxins; Food Microbiology; Gram-Negative Bacterial Infections; Hemolysis; Humans; Incidence; Vero Cells
PubMed: 11934569
DOI: 10.1111/j.1574-695X.2002.tb00559.x -
Journal of Applied Microbiology May 2018To perform a microbiological survey regarding the presence, prevalence and characterization of Aeromonas sp. and Vibrio sp. in debilitated wrecked marine birds recovered...
AIMS
To perform a microbiological survey regarding the presence, prevalence and characterization of Aeromonas sp. and Vibrio sp. in debilitated wrecked marine birds recovered from the centre-north coast of the state of Rio de Janeiro, Brazil.
METHODS AND RESULTS
Swabs obtained from 116 alive and debilitated wrecked marine birds, comprising 19 species, from the study area were evaluated by biochemical methods. Antimicrobial susceptibility tests and pathogenicity gene screening were performed for bacterial strains of public health importance. Vibrio sp. and Aeromonas sp. were identified, as well as certain pathogenic genes and resistance to selected antimicrobials.
CONCLUSIONS
This study demonstrates that the identified bacteria, mainly Vibrio sp., are fairly prevalent and widespread among several species of seabirds and highlights the importance of migratory birds in bacterial dispersion. In addition, it demonstrates the importance of the bacterial strains regarding their pathogenic potential. Therefore, seabirds can act as bacterial reservoirs, and their monitoring is of the utmost importance in a public health context.
SIGNIFICANCE AND IMPACT OF THE STUDY
The study comprehensively evaluates the importance of seabirds as bacteria of public health importance reservoirs, since birds comprising several pathogenic bacterial species were evaluated.
Topics: Aeromonas; Animals; Anti-Infective Agents; Birds; Brazil; Disease Reservoirs; Drug Resistance; Microbial Sensitivity Tests; Public Health; Surveys and Questionnaires; Vibrio; Virulence
PubMed: 29356247
DOI: 10.1111/jam.13705