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Journal of Infection in Developing... Nov 2014Aeromonas are food- and water-borne bacteria that are considered to be zoonotic human pathogens. This study aimed to investigate the presence of genes associated with...
INTRODUCTION
Aeromonas are food- and water-borne bacteria that are considered to be zoonotic human pathogens. This study aimed to investigate the presence of genes associated with virulence in human and animal Aeromonas isolates and the potential role of animal isolates with regards to human Aeromonas infections.
METHODOLOGY
The presence of aerA, hlyA, alt, ast, laf, ascF-G, stx1 and stx2 putative virulence genes in 40 human and animal Aeromonas isolates (16 human and 24 animal isolates) were examined by polymerase chain reaction (PCR). DNA fragments of expected sizes were purified and sequenced. BLAST in the NCBI was used to verify any amplified products.
RESULTS
PCR screening showed that hlyA, alt, and laf genes were determined at ratios of 6.25%, 50%, and 6.25%, respectively, in human isolates. The ratios of hlyA, alt, ascF-G, laf, stx2, and stx1 genes in animal isolates were 58.3%, 20.83%, 33.3%, 20.83%, 8.33%, and 4.17%, respectively. Neither aerA nor ast genes were detected in any isolates. Any one of eight putative virulence genes was not detected in seven human and eight animal isolates in the study.
CONCLUSIONS
The current study is the first to investigate the presence of the virulence gene in gull Aeromonas isolates. The manifestation of the presence of the virulence gene and gene combinations was considerable, especially in fish and gull isolates when compared with clinical human isolates. The current study demonstrates the potential importance of fish and gulls in terms of human Aeromonas infections.
Topics: Aeromonas; Animals; Charadriiformes; DNA, Bacterial; Fishes; Genes, Bacterial; Gram-Negative Bacterial Infections; Humans; Polymerase Chain Reaction; Sequence Analysis, DNA; Virulence Factors
PubMed: 25390052
DOI: 10.3855/jidc.4879 -
MBio 2011The vast majority of bacterial species remain uncultured, and this severely limits the investigation of their physiology, metabolic capabilities, and role in the...
UNLABELLED
The vast majority of bacterial species remain uncultured, and this severely limits the investigation of their physiology, metabolic capabilities, and role in the environment. High-throughput sequencing of RNA transcripts (RNA-seq) allows the investigation of the diverse physiologies from uncultured microorganisms in their natural habitat. Here, we report the use of RNA-seq for characterizing the metatranscriptome of the simple gut microbiome from the medicinal leech Hirudo verbana and for utilizing this information to design a medium for cultivating members of the microbiome. Expression data suggested that a Rikenella-like bacterium, the most abundant but uncultured symbiont, forages on sulfated- and sialated-mucin glycans that are fermented, leading to the secretion of acetate. Histological stains were consistent with the presence of sulfated and sialated mucins along the crop epithelium. The second dominant symbiont, Aeromonas veronii, grows in two different microenvironments and is predicted to utilize either acetate or carbohydrates. Based on the metatranscriptome, a medium containing mucin was designed, which enabled the cultivation of the Rikenella-like bacterium. Metatranscriptomes shed light on microbial metabolism in situ and provide critical clues for directing the culturing of uncultured microorganisms. By choosing a condition under which the desired organism is rapidly proliferating and focusing on highly expressed genes encoding hydrolytic enzymes, binding proteins, and transporters, one can identify an organism's nutritional preferences and design a culture medium.
IMPORTANCE
The number of prokaryotes on the planet has been estimated to exceed 10(30) cells, and the overwhelming majority of them have evaded cultivation, making it difficult to investigate their ecological, medical, and industrial relevance. The application of transcriptomics based on high-throughput sequencing of RNA transcripts (RNA-seq) to microorganisms in their natural environment can provide investigators with insight into their physiologies under optimal growth conditions. We utilized RNA-seq to learn more about the uncultured and cultured symbionts that comprise the relatively simple digestive-tract microbiome of the medicinal leech. The expression data revealed highly expressed hydrolytic enzymes and transporters that provided critical clues for the design of a culture medium enabling the isolation of the previously uncultured Rikenella-like symbiont. This directed culturing method will greatly aid efforts aimed at understanding uncultured microorganisms, including beneficial symbionts, pathogens, and ecologically relevant microorganisms, by facilitating genome sequencing, physiological characterization, and genetic manipulation of the previously uncultured microbes.
Topics: Acetates; Aeromonas; Animals; Bacterial Physiological Phenomena; Bacteriological Techniques; Bacteroidetes; Carbohydrate Metabolism; Cluster Analysis; Culture Media; DNA, Bacterial; Gene Expression Profiling; High-Throughput Nucleotide Sequencing; Leeches; Metagenomics; Molecular Sequence Data; Mucins; Phylogeny; Polysaccharides; Sequence Analysis, DNA; Symbiosis
PubMed: 21467263
DOI: 10.1128/mBio.00012-11 -
Applied and Environmental Microbiology Jan 2014The genus Aeromonas includes some species that have now been identified as human pathogens of significant medical importance. We investigated the ability of 13 selected...
The genus Aeromonas includes some species that have now been identified as human pathogens of significant medical importance. We investigated the ability of 13 selected Aeromonas strains belonging to nine species isolated from clinical cases (n = 5), environmental waters (n = 5), and fish (n = 3) to adhere to and translocate Caco-2 cells in the absence and presence of two lactic acid bacteria (LAB), i.e., Lactobacillus acidophilus and Bifidobacterium breve. Aeromonas isolates were also assessed for their cytotoxicity, the presence of virulence genes, and hemolysin production. Among the clinical isolates, one strain of Aeromonas veronii biovar veronii and two strains of Aeromonas hydrophila carried cytotoxin (act), heat-labile toxin (alt), hemolysin (hlyA), and aerolysin (aerA) genes, were cytotoxic to Vero cells, produced hemolysin, and showed higher adherence to Caco-2 cells. In contrast, this was seen in only one environmental strain, a strain of A. veronii biovar sobria. When Aeromonas strains were coinoculated with LAB onto Caco-2 cells, their level of adhesion was reduced. However, their rate of translocation in the presence of LAB increased and was significantly (P < 0.05) higher among fish strains. We suggest that either the interaction between Aeromonas and LAB strains could have a detrimental effect on the Caco-2 cells, allowing the Aeromonas to translocate more readily, or the presence of the LAB stimulated the Aeromonas strains to produce more toxins and/or increase their translocation rate.
Topics: Aeromonas; Animals; Bacterial Adhesion; Bacterial Toxins; Bifidobacterium; Caco-2 Cells; Chlorocebus aethiops; Fish Diseases; Hemolysin Proteins; Humans; Lactic Acid; Lactobacillus acidophilus; Pore Forming Cytotoxic Proteins; Vero Cells; Virulence
PubMed: 24242240
DOI: 10.1128/AEM.03200-13 -
Genome Biology and Evolution May 2020Aeromonads are ubiquitous aquatic bacteria that cause opportunistic infections in humans, but their pathogenesis remains poorly understood. A pathogenomic approach was... (Comparative Study)
Comparative Study
Aeromonads are ubiquitous aquatic bacteria that cause opportunistic infections in humans, but their pathogenesis remains poorly understood. A pathogenomic approach was undertaken to provide insights into the emergence and evolution of pathogenic traits in aeromonads. The genomes of 64 Aeromonas strains representative of the whole genus were analyzed to study the distribution, phylogeny, and synteny of the flanking sequences of 13 virulence-associated genes. The reconstructed evolutionary histories varied markedly depending on the gene analyzed and ranged from vertical evolution, which followed the core genome evolution (alt and colAh), to complex evolution, involving gene loss by insertion sequence-driven gene disruption, horizontal gene transfer, and paraphyly with some virulence genes associated with a phylogroup (aer, ser, and type 3 secretion system components) or no phylogroup (type 3 secretion system effectors, Ast, ExoA, and RtxA toxins). The general pathogenomic overview of aeromonads showed great complexity with diverse evolution modes and gene organization and uneven distribution of virulence genes in the genus; the results provided insights into aeromonad pathoadaptation or the ability of members of this group to emerge as pathogens. Finally, these findings suggest that aeromonad virulence-associated genes should be examined at the population level and that studies performed on type or model strains at the species level cannot be generalized to the whole species.
Topics: Adaptation, Physiological; Aeromonas; Biological Evolution; Genome, Bacterial; Genomics; Genotype; Humans; Phenotype; Phylogeny; Virulence; Virulence Factors
PubMed: 32196086
DOI: 10.1093/gbe/evaa055 -
PloS One 2012Species of the genus Aeromonas are native inhabitants of aquatic environments and have recently been considered emerging human pathogens. Although the gastrointestinal...
BACKGROUND
Species of the genus Aeromonas are native inhabitants of aquatic environments and have recently been considered emerging human pathogens. Although the gastrointestinal tract is by far the most common anatomic site from which aeromonads are recovered, their role as etiologic agents of bacterial diarrhea is still disputed. Aeromonas-associated diarrhea is a phenomenon occurring worldwide; however, the exact prevalence of Aeromonas infections on a global scale is unknown.
METHODOLOGY/PRINCIPAL FINDINGS
The prevalence and virulence potential of Aeromonas in patients suffering from diarrhea in Israel was studied using molecular methods. 1,033 diarrheal stools were sampled between April and September 2010 and Aeromonas species were identified in 17 (∼2%) patients by sequencing the rpoD gene. Aeromonas species identity and abundance was: A. caviae (65%), A. veronii (29%) and Aeromonas taiwanensis (6%). This is the first clinical record of A. taiwanensis as a diarrheal causative since its recent discovery from a wound infection in a patient in Taiwan. Most of the patients (77%) from which Aeromonas species were isolated were negative for any other pathogens. The patients ranged from 1 to 92 years in age. Aeromonas isolates were found to possess different virulence-associated genes: ahpB (88%), pla/lip/lipH3/apl-1 (71%), act/hlyA/aerA (35%), alt (18%), ast (6%), fla (65%), lafA (41%), TTSS ascV (12%), TTSS ascF-ascG (12%), TTSS-dependent ADP-ribosylating toxins aexU (41%) and aexT (6%) in various combinations. Most of the identified strains were resistant to beta-lactam antibiotics but susceptible to third-generation cephalosporin antibiotics.
CONCLUSIONS
Aeromonas may be a causative agent of diarrhea in patients in Israel and therefore should be included in routine bacteriological screenings.
Topics: Adolescent; Adult; Aeromonas; Aged; Aged, 80 and over; Anti-Infective Agents; Bacterial Proteins; Child; Child, Preschool; Diarrhea; Feces; Gram-Negative Bacterial Infections; Humans; Infant; Israel; Middle Aged; Molecular Sequence Data; Phylogeny; Prevalence; Virulence; Virulence Factors; Young Adult
PubMed: 22355306
DOI: 10.1371/journal.pone.0030070 -
Frontiers in Cellular and Infection... 2020is a Gram-negative species ubiquitous in different aquatic environments and capable of causing a variety of diseases to a broad host range. species have the capability...
is a Gram-negative species ubiquitous in different aquatic environments and capable of causing a variety of diseases to a broad host range. species have the capability to carry and acquire antimicrobial resistance (AMR) elements, and currently multi-drug resistant (MDR) isolates are commonly found across the world. strain MS-17-88 is a MDR strain isolated from catfish in the southeastern United States. The present study was undertaken to uncover the mechanism of resistance in MDR strain MS-17-88 through the detection of genomic features. To achieve this, genomic DNA was extracted, sequenced, and assembled. The strain MS-17-88 genome comprised 5,178,226-bp with 58.6% G+C, and it encoded several AMR elements, including , and . The phylogeny and resistance profile of a large collection of strains, including MS-17-88, were evaluated. Phylogenetic analysis showed a close relationship between MS-17-88 and strain Ae5 isolated from fish in China and ARB3 strain isolated from pond water in Japan, indicating a common ancestor of these strains. Analysis of phage elements revealed 58 intact, 63 incomplete, and 15 questionable phage elements among the 53 genomes. The average phage element number is 2.56 per genome, and strain MS-17-88 is one of two strains having the maximum number of identified prophage elements (6 elements each). The profile of resistance against various antibiotics across the 53 genomes revealed the presence of , and in all genomes (100%). By comparison, and were detected in 7.5% and 1.8% of genomes. Nearly 77% of strains carried , and 7.5% of strains carried . This result suggested a low abundance and prevalence of sulfonamide and florfenicol resistance genes compared with tetracycline resistance among strains. Overall, the present study provides insights into the resistance patterns among 53 genomes, which can inform therapeutic options for fish affected by .
Topics: Aeromonas; Aeromonas veronii; Animals; Anti-Bacterial Agents; China; Drug Resistance, Bacterial; Ictaluridae; Japan; Microbial Sensitivity Tests; Phylogeny
PubMed: 32766165
DOI: 10.3389/fcimb.2020.00348 -
Applied and Environmental Microbiology Dec 1999We found 73.1 to 96.9% similarity by aligning the cytolytic enterotoxin gene of Aeromonas hydrophila SSU (AHCYTOEN; GenBank accession no. M84709) against aerolysin genes...
We found 73.1 to 96.9% similarity by aligning the cytolytic enterotoxin gene of Aeromonas hydrophila SSU (AHCYTOEN; GenBank accession no. M84709) against aerolysin genes of Aeromonas spp., suggesting the possibility of selecting common primers. Identities of 90 to 100% were found among the eight selected primers from those genes. Amplicons obtained from Aeromonas sp. reference strains by using specific primers for each gene or a cocktail of primers were 232 bp long. Of hybridization group 4/5A/5B (HG4/5A/5B), HG9, and HG12 or non-Aeromonas reference strains, none were positive. PCR-restriction fragment length polymorphism (PCR-RFLP) with HpaII yielded three types of patterns. PCR-RFLP 1 contained two fragments (66 and 166 bp) found in HG6, HG7, HG8, HG10, and HG11. PCR-RFLP 2 contained three fragments (18, 66, and 148 bp) found in HG1, HG2, HG3, and HG11. PCR-RFLP 3, with four fragments (7, 20, 66, and 139 bp), was observed only in HG13. PCR-amplicon sequence analysis (PCR-ASA) revealed three main types. PCR-ASA 1 had 76 to 78% homology with AHCYTOEN and included strains in HG6, HG7, HG8, HG10, and HG11. PCR-ASA 2, with 82% homology, was found only in HG13. PCR-ASA 3, with 91 to 99% homology, contained the strains in HG1, HG2, HG3, and HG11. This method indicated that 37 (61%) of the 61 reference strains were positive with the primer cocktail master mixture, and 34 (58%) of 59 environmental isolates, 93 (66%) of 141 food isolates, and 100 (67%) of 150 clinical isolates from around the world carried a virulence factor when primers AHCF1 and AHCR1 were used. In conclusion, this PCR-based method is rapid, sensitive, and specific for the detection of virulence factors of Aeromonas spp. It overcomes the handicap of time-consuming biochemical and other DNA-based methods.
Topics: Aeromonas; Animals; Bacterial Toxins; Cattle; DNA Primers; Deoxyribonuclease HpaII; Europe; Hemolysin Proteins; Meat; Molecular Sequence Data; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Pore Forming Cytotoxic Proteins; Poultry; Seafood; Swine; Vegetables; Virulence
PubMed: 10583979
DOI: 10.1128/AEM.65.12.5293-5302.1999 -
Microbiology (Reading, England) May 2021The bacterial species is a fish pathogen. Feared by fish farmers everywhere on Earth over the past century, this species has turned out to be more diverse than...
The bacterial species is a fish pathogen. Feared by fish farmers everywhere on Earth over the past century, this species has turned out to be more diverse than initially suspected. While some psychrophilic subspecies cannot grow at temperatures above 25 °C or 30 °C, other mesophilic strains growing up to 37 °C and above are now characterized. Adding to the surprising diversity of this species, some of the mesophilic strains infect mammals and birds. The remarkable diversity is explained in part by the presence of numerous mobile genetic elements, which sculpt and modify the genome of the various strains of this species.
Topics: Aeromonas salmonicida; Animals; Biodiversity; DNA Transposable Elements; Fish Diseases; Fishes; Gram-Negative Bacterial Infections; Temperature
PubMed: 33945463
DOI: 10.1099/mic.0.001052 -
Journal of Applied Microbiology Jun 2001To study the phenotypic and chemotaxonomic (i.e. phospholipid and cellular fatty acid composition) characteristics of environmental Aeromonas spp. and Vibrio spp....
AIMS
To study the phenotypic and chemotaxonomic (i.e. phospholipid and cellular fatty acid composition) characteristics of environmental Aeromonas spp. and Vibrio spp. isolated from a drinking water reservoir near Vladivostok City, and the application of some chemotaxonomic markers for discrimination of the two genera and species.
METHODS AND RESULTS
Presumptive Aeromonas species were dominant in surface water samples (up to 25% of the total number of bacteria recovered). These strains were consistent with respect to the cultural and biochemical properties used to define the species Aeromonas sobria (seven strains) and Aer. popoffii (three strains). Vibrio mimicus (two strains) and Vibrio metschnikovii (one strain) were identified according to phenotypic features and cellular fatty acid composition.
CONCLUSION
Environmental Aer. sobria isolates were atypical in their ability to grow at 42 degrees C, and were haemolytic, proteolytic and cytotoxic. Although it was present in a high proportion in the water samples, atypical Aer. sobria is not an indicator of polluted water.
SIGNIFICANCE AND IMPACT OF THE STUDY
The incidence of Aeromonas in the drinking water reservoirs in the Far East of Russia is reported for the first time.
Topics: Aeromonas; Bacterial Typing Techniques; Asia, Eastern; Fatty Acids; Fresh Water; Phenotype; Phospholipids; Russia; Vibrio; Water Microbiology; Water Supply
PubMed: 11412322
DOI: 10.1046/j.1365-2672.2001.01318.x -
Journal of Applied Microbiology Jan 2019Yesso scallop (Patinopecten yessoensis) is a popular seafood in Korea. Aeromonas spp., well-known pathogenic bacteria, has been reported in some molluscan shellfish, but...
Aeromonas spp. from marketed Yesso scallop (Patinopecten yessoensis): molecular characterization, phylogenetic analysis, virulence properties and antimicrobial susceptibility.
AIMS
Yesso scallop (Patinopecten yessoensis) is a popular seafood in Korea. Aeromonas spp., well-known pathogenic bacteria, has been reported in some molluscan shellfish, but it has not been studied in scallops so far. Therefore, we aimed to isolate, identify and characterize the Aeromonas spp. isolated from marketed Yesso scallops to estimate their potential risk to public health.
METHODS AND RESULTS
Thirty-two Aeromonas spp. including A. hydrophila (n = 13), A. salmonicida (n = 11), A. media (n = 3), A. caviae (n = 2), A. veronii (n = 2) and A. enteropelogenes (n = 1) were isolated from 105 marketed scallops and tested for phenotypic pathogenicity, virulence genes and antimicrobial susceptibility. Mean total bacterial count of scallop meat was 1·34 × 10 CFU per gram. Slime production and lipase tests were positive in 97% of the isolates while DNase, protease, gelatinase, phospholipase and haemolysis were shown by 88, 88, 81, 88 and 72% of the isolates respectively. Eleven virulence genes were detected among Aeromonas spp. (act (75%), alt (59%), ast (47%), aerA (78%), lip (59%), ahyB (94%), ser (75%), hlyA (75%), fla (64%), gcat (84%) and ascV (23%)), and exu was negative in all isolates. Aeromonas hydrophila and A. salmonicida harboured ≥7 virulence genes and positive for enterotoxin genes, act, alt and ast. All the isolates were multidrug resistant and 100% resistant to ampicillin, colistin, vancomycin and cephalothin. Also, 30, 31, 20, 21, 29, 24, 27 and 27 of the isolates were resistant to piperacillin, clindamycin, erythromycin, nalidixic acid, imipenem, meropenem, trimethoprim-sulfamethoxazole and rifampicin respectively.
CONCLUSIONS
It is obvious with our results that the Aeromonas spp. isolated from Yesso scallops are highly virulent and potentially pathogenic, whereas the multidrug resistance further expedite their importance.
SIGNIFICANCE AND IMPACT OF THE STUDY
To our knowledge, this is the first study reporting Aeromonas spp. in scallop. This implies that not only the common varieties like oysters, but other bivalves can also harbour potentially pathogenic aeromonads which may have impacts on consumer health.
Topics: Aeromonas; Animals; Anti-Bacterial Agents; Pectinidae; Phylogeny; Seafood; Virulence
PubMed: 30218592
DOI: 10.1111/jam.14106