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Toxins Oct 2016ExoU, a type III secretory toxin and major virulence factor with patatin-like phospholipase activity, is responsible for acute lung injury and sepsis in... (Review)
Review
ExoU, a type III secretory toxin and major virulence factor with patatin-like phospholipase activity, is responsible for acute lung injury and sepsis in immunocompromised patients. Through use of a recently updated bacterial genome database, protein sequences predicted to be homologous to ExoU were identified in 17 other species (, , , , , , , , , , , , , , and ) and 8 Gram-negative bacteria from three other genera (, , and ). In the alignment of the predicted primary amino acid sequences used for the phylogenetic analyses, both highly conserved and nonconserved parts of the toxin were discovered among the various species. Further comparative studies of the predicted ExoU homologs should provide us with more detailed information about the unique characteristics of the ExoU toxin.
Topics: Animals; Bacterial Proteins; Bacterial Toxins; Gram-Negative Bacteria; Humans; Molecular Chaperones; Phospholipases
PubMed: 27792159
DOI: 10.3390/toxins8110307 -
Veterinary Research Forum : An... 2018The purpose of the present study was to isolate and identify the pathogenic agents in (Pallas, 1771) and (Linnaeus, 1758) reared in the south of Fars province, Iran...
The purpose of the present study was to isolate and identify the pathogenic agents in (Pallas, 1771) and (Linnaeus, 1758) reared in the south of Fars province, Iran which have shown infectious disease signs. Samples from spleen and kidney of 32 fishes showing septicemia symptoms such as decreasing of appetite, unbalanced swimming, expanded wounds, and petechia on the body surfaces, pectoral fins rot, visceral hemorrhage, bleeding on the spleen, and heart ascites were collected. Then samples were cultured on brain heart infusion agar growth media, stain and biological and biochemical tests on purified bacteria were performed. On the other hand, 16S rDNA region of the isolated organism was amplified using PCR. The amplified gene fragment was sequenced and evolutionary history was inferred by phylogenetic tree construction using neighbor-joining method. Results indicated that two bacterial species including which isolated from the kidney of stellate sturgeon (43.00%), and which isolated from the spleen of both sturgeon species (75.00% and 31.00% from beluga and stellate sturgeon, respectively), were recognized. Phylogenetic tree analysis showed that Fars isolated organisms including and had highest similarity with and isolated from France, respectively.
PubMed: 30065799
DOI: 10.30466/VRF.2018.30826 -
Microbiology Resource Announcements Feb 2023The genomes of seven Aeromonas veronii strains isolated from tissues of healthy or diseased channel catfish obtained from Alabama, USA, fish farms were sequenced and...
The genomes of seven Aeromonas veronii strains isolated from tissues of healthy or diseased channel catfish obtained from Alabama, USA, fish farms were sequenced and annotated. These genome sequences will enable comparative analyses to determine the roles these bacteria play in catfish aquaculture and the development of new preventative or management strategies.
PubMed: 36700629
DOI: 10.1128/mra.01231-22 -
BMC Microbiology Jun 2021Aeromonas veronii is a bacterial pathogen in aquaculture, which produces virulence factors to enable it colonize and evade host immune defense. Given that experimental...
BACKGROUND
Aeromonas veronii is a bacterial pathogen in aquaculture, which produces virulence factors to enable it colonize and evade host immune defense. Given that experimental verification of virulence factors is time-consuming and laborious, few virulence factors have been characterized. Moreover, most studies have only focused on single virulence factors, resulting in biased interpretation of the pathogenesis of A. veronii.
RESULTS
In this study, a PPI network at genome-wide scale for A. veronii was first constructed followed by prediction and mapping of virulence factors on the network. When topological characteristics were analyzed, the virulence factors had higher degree and betweenness centrality than other proteins in the network. In particular, the virulence factors tended to interact with each other and were enriched in two network modules. One of the modules mainly consisted of histidine kinases, response regulators, diguanylate cyclases and phosphodiesterases, which play important roles in two-component regulatory systems and the synthesis and degradation of cyclic-diGMP. Construction of the interspecies PPI network between A. veronii and its host Oreochromis niloticus revealed that the virulence factors interacted with homologous proteins in the host. Finally, the structures and interacting sites of the virulence factors during interaction with host proteins were predicted.
CONCLUSIONS
The findings here indicate that the virulence factors probably regulate the virulence of A. veronii by involving in signal transduction pathway and manipulate host biological processes by mimicking and binding competitively to host proteins. Our results give more insight into the pathogenesis of A. veronii and provides important information for designing targeted antibacterial drugs.
Topics: Aeromonas veronii; Animals; Cichlids; Fish Diseases; Genome, Bacterial; Gram-Negative Bacterial Infections; Virulence Factors
PubMed: 34162325
DOI: 10.1186/s12866-021-02261-8 -
Microorganisms Dec 2022This study aimed to evaluate antimicrobial resistance, virulence, and the genetic diversity of isolated from migratory birds from Guangxi Province, Guangdong Province,...
This study aimed to evaluate antimicrobial resistance, virulence, and the genetic diversity of isolated from migratory birds from Guangxi Province, Guangdong Province, Ningxia Hui Autonomous Region, Jiangxi Province, and Inner Mongolia in China. A total of 810 samples were collected, including fresh feces, cloacal swabs, and throat swabs. The collected samples were processed and subjected to bacteriological examination. The resistance to 21 antibiotics was evaluated. A phylogenetic tree was constructed using concatenated ----- sequences. Eight putative virulence factors were identified by PCR and sequencing, and a biofilm formation assay was performed using a modified microtiter plate method. In total, 176 isolates were isolated including , , , and . All isolates showed variable resistance against all 16 tested antibiotic discs, and only one antibiotic had no reference standard. Six kinds of virulence gene markers were discovered, and the detection rates were 46.0% (), 76.1% (), 52.3% (), 4.5% (), 54.0% (), and 64.2% (). These strains were able to form biofilms with distinct magnitudes; 102 were weakly adherent, 14 were moderately adherent, 60 were non-adherent, and none were strongly adherent. Our results suggest that migratory birds carry highly virulent and multidrug-resistant and spread them around the world through migration, which is a potential threat to public health.
PubMed: 36677299
DOI: 10.3390/microorganisms11010007 -
Microorganisms Oct 2021The aims of this study were to characterize and investigate antimicrobial susceptibility and presence of integrons in 161 spp. isolated from ornamental freshwater fish...
Characterization and Antimicrobial Resistance of Environmental and Clinical Species Isolated from Fresh Water Ornamental Fish and Associated Farming Environment in Sri Lanka.
The aims of this study were to characterize and investigate antimicrobial susceptibility and presence of integrons in 161 spp. isolated from ornamental freshwater fish farming environment, apparently healthy and diseased fish. Phylogenetic analyses of the gene sequences identified as the most abundant species (75.8%) followed by (9.3%), (5%), (4.3%), (3.7%), (0.6%), (0.6%), and (0.6%). Susceptibility to thirteen antimicrobials was determined and antimicrobial resistance frequencies were: amoxicillin (92.5%), enrofloxacin (67.1%), nalidixic acid (63.4%), erythromycin (26.1%), tetracycline (23.6%), imipenem (18%), trimethoprim-sulfamethoxazole (16.8%), and gentamicin (16.8%). Multi-drug resistance (MDR) was widespread among the isolates (51.6%, 83/161) with 51.6% (63/122) isolates being MDR. In addition, 68.3% of isolates had multiple antibiotic resistance (MAR) indexes higher than 0.2, suggesting that they originated from a high-risk source of contamination where antimicrobials are often used. In all, 21.7% isolates carried class 1 integrons, with 97.1% having gene cassettes, while there were 12 isolates carrying class 2 integron gene cassettes. Our findings highlight that the aquatic environment and ornamental fish act as reservoirs of multidrug resistant spp. and underline the need for a judicious use of antimicrobials and timely surveillance of antimicrobial resistance (AMR) in aquaculture.
PubMed: 34683427
DOI: 10.3390/microorganisms9102106 -
Microbiology Spectrum Sep 2023species are emerging human enteric pathogens. This study examines the isolation of and other enteric bacterial pathogens from patients with and without inflammatory...
species are emerging human enteric pathogens. This study examines the isolation of and other enteric bacterial pathogens from patients with and without inflammatory bowel disease (IBD). This study also investigates the intestinal epithelial pathogenic mechanisms of . The isolation rates of seven enteric bacterial pathogens from 2,279 patients with IBD and 373,276 non-IBD patients were compared. An strain (AS1) isolated from intestinal biopsies of a patient with IBD was used for pathogenic mechanism investigation, and K12 was used as a bacterial control. HT-29 cells were used as a model of human intestinal epithelium. A significantly higher isolation of species was found in patients with IBD as compared to non-IBD patients ( = 0.0001, odds ratio = 2.11). upregulated 177 inflammatory genes and downregulated 52 protein-coding genes affecting chromatin assembly, multiple small nuclear RNAs, multiple nucleolar RNAs, and 55 cytoplasmic tRNAs in HT-29 cells. These downregulation effects were unique to and not observed in HT-29 cells infected with K12. induced intestinal epithelial apoptosis involving the intrinsic pathway. caused epithelial microvilli shortening and damage and epithelial production of IL-8. In conclusion, this study for the first time reports the association between IBD and enteric infection detected by bacterial cultivation. This study also reports that damages intestinal epithelial cells via multiple mechanisms, of which the downregulating cytoplasmic tRNA, small nuclear RNA, and small nucleolar RNA are novel bacterial pathogenic mechanisms. IMPORTANCE This study for the first time reports the association between inflammatory bowel disease (IBD) and enteric infection detected by bacterial pathogen cultivation, highlighting the need of clinical and public health attention. The finding that patients with IBD are more susceptible to enteric infection suggests that detection of enteric infection should be routinely performed for the diagnosis and treatment of IBD. This study also reports novel bacterial pathogenic mechanisms employed by . Through comparative transcriptomic analysis and other techniques, this study revealed the pathogenic mechanisms by which causes damage to intestinal epithelial cells. Among the various pathogenic mechanisms identified, the downregulating tRNA, small nuclear and nucleolar RNAs in human intestinal epithelial cells are novel bacterial pathogenic mechanisms.
PubMed: 37732778
DOI: 10.1128/spectrum.01088-23 -
Animals : An Open Access Journal From... Sep 2021The aim of the study was to isolate and identify species belonging to the genus and evaluate the antimicrobial resistance and virulence patterns of isolates colonizing...
The aim of the study was to isolate and identify species belonging to the genus and evaluate the antimicrobial resistance and virulence patterns of isolates colonizing European pond turtles () from natural environment of Eastern Poland. In total, 74 turtles and 15 samples of water from their natural environment were examined. More than 40 strains were isolated and identified: ( = 1), ( = 13), ( = 2), ( = 3), and ( = 23). The highest incidence of resistance was noted for ampicillin (100%) and sulfamethoxazole (62.0%), followed by erythromycin and colistin (both 40.5%). Moreover, eight strains were intermediately resistant to meropenem (19%). Most isolates were found to possess more than one virulence gene among A, , and . We showed that the population of free-living European pond turtles was highly colonized by spp. Such strains may be an infectious agent not only for the population of turtles but also for other species of animals inhabiting their natural environment. Moreover, the undesirable properties of water quality caused by the presence of drug-resistant aeromonads could have a negative impact on human health.
PubMed: 34679794
DOI: 10.3390/ani11102772 -
Biomedical and Environmental Sciences :... Sep 2022has recently been recognized as an emerging human pathogen. -associated diarrhea is a phenomenon occurring worldwide. This study was designed to determine the...
OBJECTIVE
has recently been recognized as an emerging human pathogen. -associated diarrhea is a phenomenon occurring worldwide. This study was designed to determine the prevalence, genetic diversity, antibiotic resistance, and pathogenicity of strains isolated from food products in Shanghai.
METHODS
isolates ( = 79) collected from food samples were analyzed using concatenated - sequencing. The antibiotic resistance of these isolates was determined using antimicrobial susceptibility testing. Pathogenicity was assessed using β-hemolytic, extracellular protease, virulence gene detection, liquid toxicity (LT), and cytotoxicity assays.
RESULTS
Eight different species were identified among the 79 isolates. The most prevalent species were [62 (78.5%)], [6 (7.6%)], [3 (3.8%)], and [3 (3.8%)]. The isolates were divided into 73 sequence types (STs), of which 65 were novel. The isolates were hemolytic (45.6%) and protease-positive (81.0%). The most prevalent virulence genes were (73.4%), (69.6%), (36.7%), and (30.4%). The results of LT and cytotoxicity assays revealed that and were more virulent than , , and . Antibiotic resistance genes [ , , , , , mcr , and ] were detected in the isolates. The multidrug-resistance rate of the isolates was 11.4%, and 93.7% of the isolates were resistant to cefazolin.
CONCLUSION
The taxonomy, antibiotic resistance, and pathogenicity of different species varied. The isolates and were highly pathogenic, indicating that food-derived isolates are potential risks for public health and food safety. The monitoring of food quality and safety will result in better prevention and treatment strategies to control diarrhea illnesses in China.
Topics: Aeromonas; Animals; Anti-Bacterial Agents; Caenorhabditis elegans; Cefazolin; China; Diarrhea; Drug Resistance, Multiple, Bacterial; Genetic Variation; Humans; Peptide Hydrolases; Virulence
PubMed: 36189999
DOI: 10.3967/bes2022.108 -
Frontiers in Microbiology 2019species often cause disease in farmed fish. In the present study, dominant bacteria were isolated from diseased crucian carp (). Based on this, a bacterial isolate was...
species often cause disease in farmed fish. In the present study, dominant bacteria were isolated from diseased crucian carp (). Based on this, a bacterial isolate was tentatively named CFJY-623. This isolate was identified as based on analysis of its morphological, physiological, and biochemical features, as well as 16S rRNA and gene sequences. Six virulence genes related to pathogenicity including aerolysin, cytotonic enterotoxins, elastase, glycerophospholipid: cholesterol acyltransferase, lipase, and serine protease were identified in this isolate. The median lethal dosage (LD50) of the CFJY-623 isolate for crucian carp was determined as 1.31 × 10 CFU/mL. Artificial experimental infection showed that the CFJY-623 isolate caused considerable histological lesions in the fish, including tissue cell degeneration, necrosis, and inflammatory cell infiltrating. Drug sensitivity testing showed that the isolate was susceptible to aminoglycosides, carbapenemes, and nitrofurans. Exploring its growing features showed that this isolate exhibited a high level of environmental adaptability. These results provided a scientific basis for the identification of and treatment for fish infected by this pathogen.
PubMed: 32038507
DOI: 10.3389/fmicb.2019.02742