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Letters in Applied Microbiology Aug 2021Aeromonas spp. are associated with seafood-related outbreaks worldwide. In seafood industry, shellfish play a major role in global seafood production. With this emerging... (Review)
Review
Aeromonas spp. are associated with seafood-related outbreaks worldwide. In seafood industry, shellfish play a major role in global seafood production. With this emerging trend of shellfish consumption, shellfish-related bacterial infections are being reported frequently. Aeromonas spp. are natural contaminants found in shellfish. Although 36 species have been identified, some species including Aeromonas hydrophila, Aeromonas caviae and Aeromonas veronii biotype sobria have dragged major attention as foodborne pathogenic bacteria. The ability to elaborate a variety of virulence factors of Aeromonas spp. contributes to the pathogenic activities. Also, emerging antimicrobial resistance in Aeromonas spp. has become a huge challenge in seafood industry. Furthermore, multidrug resistance increases the risk of consumer health. Studies have supplied pieces of evidence about the emerging health risk of Aeromonas spp. isolated from seafood. Therefore, the present review was intended to highlight the prevalence, virulence and antimicrobial resistance of Aeromonas spp. isolated from various types of shellfish.
Topics: Aeromonas; Aeromonas caviae; Aeromonas hydrophila; Aeromonas veronii; Animals; Anti-Bacterial Agents; Biofilms; Drug Resistance, Bacterial; Food Contamination; Food Microbiology; Humans; Prevalence; Seafood; Shellfish; Virulence; Virulence Factors
PubMed: 33891720
DOI: 10.1111/lam.13489 -
Aquaculture International : Journal of... 2023This study aimed to develop and evaluate live and inactivated vaccines to pathogenicity in Nile tilapia. Therefore, five well-identified isolates, including A (HY1), A...
This study aimed to develop and evaluate live and inactivated vaccines to pathogenicity in Nile tilapia. Therefore, five well-identified isolates, including A (HY1), A (HY2), A (HY3), A (HY4), and A (HY6) isolated from diseased Nile tilapia (), were used for vaccine preparation. Virulence genes detected by a polymerase chain reaction (PCR) and lethal dose determination were conducted. Nile tilapia, each with a body weight of 25 ± 0.5 g were divided into six experimental groups (each of 20): T1 group (control), fish were injected with saline as a negative control, T2 group (formalin-killed vaccine) for the A (HY2) strain, T3 group ( formalized killed vaccine) for the A (HY4), T4 group (autoclaved vaccine) for the A (HY2), T5 group (autoclaved vaccine) for A (HY4), and T6 (live vaccine) for A (HY1), triplicate. At the end of the immunization period, all groups were challenged by , A (HY2). Blood samples were drawn 21 days post-immunization and 3 days after the challenge test for antibody titer assay. The results showed that the pathogenicity of strains A (HY2) and A (HY4) was the strongest, as the lethality rates (LR) were 100% and 90%, respectively, whereas the pathogenicity was moderate for strains A (HY3) and A (HY6) (LR 60% for each). A (AY1) was the weakest strain as no dead fish was found for this strain. The presence of , and genes as the main cause of the pathogenesis. The best protective efficacy was obtained from the live vaccine, A (HY1) with a protective rate of about 94.12% (relative percentage of survival, RPS), compared to autoclaved killed vaccines and formalin-killed vaccines. Based on immunoglobulin estimation (IgM) and RPS%, our data concluded that A (HY1) live vaccine had the best vaccine prophylactic effect against the highly pathogenic strain A(HY2).
PubMed: 36439703
DOI: 10.1007/s10499-022-01023-1 -
Journal of Fish Diseases Oct 2022Aeromonas veronii is a significant pathogen that is capable of infecting humans, animals, and aquatic animals. The type III secretion system (T3SS) is intimately...
Aeromonas veronii is a significant pathogen that is capable of infecting humans, animals, and aquatic animals. The type III secretion system (T3SS) is intimately associated with bacterial pathogenicity. The ascO gene is an important core component of T3SS in A. veronii, but its function is still unclear. The ascO gene of A. veronii TH0426 was deleted by using the pRE112 suicide plasmid to study its function. The study results showed that the ability of ∆ascO to adhere and invade EPC cells was significantly reduced by 1.28 times. The toxicity of the mutant strain ΔascO to EPC cells was consistently significantly lower than wild-type strain TH0426 at 1, 2, and 4 h. The LD50 values of ∆ascO against zebrafish and Carassius auratus (C. auratus) were 53 and 15 times that of the wild-type strain. In addition, the bacterial load of the mutant strain ΔascO in blood, heart, liver, and spleen was lower than wild-type strain TH0426. The Hoechst staining showed that the apoptotic degree of EPC cells induced by the mutant strain ΔascO was lower than that of the wild-type strain TH0426. Furthermore, real-time quantitative PCR (RT-qPCR) analysis revealed lower expression levels of pro-apoptotic genes (including cytC, cas3, cas9, TNF-α, and IL-1β) in C. auratus tissues infected with the mutant strain ΔascO compared to the wild-type strain TH0426. The results of in vivo and in vitro experiments have shown that ascO gene mutation can reduce the adhesion and toxicity of A. veronii to EPC and reduce the level of apoptosis induced by A. veronii. As a result, these insights will help further elucidate the function of the ascO gene and thus contribute to understanding the pathogenesis of A. veronii.
Topics: Animals; Humans; Aeromonas; Aeromonas veronii; Apoptosis; Fish Diseases; Gram-Negative Bacterial Infections; Virulence; Zebrafish
PubMed: 35749548
DOI: 10.1111/jfd.13676 -
Frontiers in Microbiology 2016Aeromonas dhakensis was first isolated from children with diarrhea in Dhaka, Bangladesh and described in 2002. In the past decade, increasing evidence indicate this... (Review)
Review
Aeromonas dhakensis was first isolated from children with diarrhea in Dhaka, Bangladesh and described in 2002. In the past decade, increasing evidence indicate this species is widely distributed in the environment and can cause a variety of infections both in human and animals, especially in coastal areas. A. dhakensis is often misidentified as A. hydrophila, A. veronii, or A. caviae by commercial phenotypic tests in the clinical laboratory. Correct identification relies on molecular methods. Increasingly used matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) may be able to identify Aeromonas specie rapidly and accurately. A. dhakensis has shown its potent virulence in different animal models and clinical infections. Although several virulence factors had been reported, no single mechanism is conclusive. Characteristically A. dhakensis is the principal species causing soft tissue infection and bacteremia, especially among patients with liver cirrhosis or malignancy. Of note, A. dhakensis bacteremia is more lethal than bacteremia due to other Aeromonas species. The role of this species in gastroenteritis remains controversial. Third generation cephalosporins and carbapenems should be used cautiously in the treatment of severe A. dhakensis infection due to the presence of AmpC ββ-lactamase and metallo-β-lactamase genes, and optimal regimens may be cefepime or fluoroquinolones. Studies of bacterial virulence factors and associated host responses may provide the chance to understand the heterogeneous virulence between species. The hypothesis A. dhakensis with varied geographic prevalence and enhanced virulence that compared to other Aeromonas species warrants more investigations.
PubMed: 27303382
DOI: 10.3389/fmicb.2016.00793 -
Genomics Jan 2021The present study was intended to elucidate the genomic basis of antibiotic resistance and hyper-virulence of the fish pathogen Aeromonas veronii XhG1.2 characterized in...
The present study was intended to elucidate the genomic basis of antibiotic resistance and hyper-virulence of the fish pathogen Aeromonas veronii XhG1.2 characterized in our previous work. The identity of XhG1.2 was confirmed through 16S rDNA sequence analysis and whole genome sequence analysis. The top-hit species distribution analysis of XhG1.2 sequence data revealed major hits against the Aeromonas veronii. The identification of virulence genes using the VFDB showed the genome of XhG1.2 to have the genes coding for the virulence factors viz. aerolysin, RtxA, T2SS, T3SS and T6SS. The presence of antibiotic resistance predicted through the CARD database analysis showed it to have the CephA3, OXA-12, adeF and pulvomycin resistance genes. By the phylogenetic and comparative genomic analysis, A. veronii species were found to have genes for toxin production. This also confirmed the pathogenicity and drug resistance of A. veronii XhG1.2 and also its potential to cause disease in diverse ornamental fishes.
Topics: Aeromonas veronii; Animals; Bacterial Proteins; Cyprinodontiformes; Drug Resistance, Bacterial; Fish Diseases; Genome, Bacterial; Gram-Negative Bacterial Infections; Virulence Factors
PubMed: 33144215
DOI: 10.1016/j.ygeno.2020.10.034 -
Journal of Fish Diseases Jun 2023The giant snakehead, Channa micropeltes, is an increasingly important economic freshwater fish in Thailand and other regions of Asia. Presently, giant snakehead are...
The giant snakehead, Channa micropeltes, is an increasingly important economic freshwater fish in Thailand and other regions of Asia. Presently, giant snakehead are cultured under intensive aquaculture conditions, leading to high stress and conditions favouring disease. In this study, we reported a disease outbreak in farmed giant snakehead with a cumulative mortality of 52.5%, continuing for 2 months. The affected fish exhibited signs of lethargy, anorexia and haemorrhage of the skin and eyes. Further bacterial isolations revealed two different types of colonies on tryptic soy agar: small white, punctate colonies of gram-positive cocci and cream-coloured, round and convex colonies of rod-shaped gram-negative bacteria. Additional biochemical and species-specific PCR analysis based on 16S rRNA confirmed the isolates as Streptococcus iniae and Aeromonas veronii. Multilocus sequence analysis (MLSA) placed the S. iniae isolate into a large clade of strains from clinically infected fish worldwide. Gross necropsy findings showed liver congestion, pericarditis and white nodules in the kidney and liver. Histologically, the affected fish showed focal to multifocal granulomas with inflammatory cell infiltration in kidney and liver, enlarged blood vessels with mild congestion within the meninges of the brain and severe necrotizing and suppurative pericarditis with myocardial infarction. Antibiotic susceptibility tests revealed that S. iniae was sensitive to amoxicillin, erythromycin, enrofloxacin, oxytetracycline, doxycycline and resistant to sulfamethoxazole-trimethoprim, while the A. veronii was susceptible to erythromycin, enrofloxacin, oxytetracycline, doxycycline, sulfamethoxazole-trimethoprim and resistant to amoxicillin. Conclusively, our findings highlighted the natural concurrent bacterial infections in cultured giant snakehead, which support the implementation of appropriate treatment and control strategies.
Topics: Animals; Aeromonas veronii; Streptococcus iniae; Oxytetracycline; Doxycycline; Enrofloxacin; RNA, Ribosomal, 16S; Fish Diseases; Fishes; Amoxicillin; Erythromycin; Pericarditis; Sulfamethoxazole; Trimethoprim; Thailand; Aeromonas
PubMed: 36866813
DOI: 10.1111/jfd.13774 -
Journal of Microbiological Methods Aug 2023Rapid and accurate detection of bacterial pathogens is critical in controlling disease outbreaks affecting farmed fish. The present study aimed to develop a novel...
Rapid and accurate detection of bacterial pathogens is critical in controlling disease outbreaks affecting farmed fish. The present study aimed to develop a novel serological diagnostic approach using nano‑silver based Enzyme-linked immunosorbent assay (ELISA) for speedy detection of Aeromonas veronii infections in Nile tilapia. A. veronii isolates used in ELISA assays were recovered from moribund Nile tilapia during a disease outbreak in a private fish farm in Egypt. A. veronii isolates were identified based on alignment analysis of the gyrB and 16S rRNA gene sequences. A. veronii antisera used in ELISA assays were prepared in tilapia, and the bacterial antigens were formalin-killed. The cut-off values were 0.46 and 0.48 in traditional and nano-based ELISA. There were no cross-reactions with bacterial isolates (Aeromonas hydrophila, Aeromonas caviae, Aeromonas sobria, Pseudomonas fluorescens, and Vibrio vulnificus). The lowest antigen concentration that produced positive results after checkerboard titration in indirect-ELISA (i-ELISA) and dot ELISA was 15 μg and 250 ng of prepared antigen, respectively. Nano-ELISA and nano-based dot-ELISA antigen concentration was 10 μg and 100 ng, respectively. Sera concentration was 1:100 in indirect-ELISA and dot-ELISA, while it was 1:50 in nano-based ELISA and nano dot-ELISA. The i-ELISA successfully detected anti-Aeromonas IgG antibodies with 83.33% sensitivity and 66.67% specificity, while in the dot-ELISA, the sensitivity and specificity were 83.33% and 100%, respectively. Nano dot-ELISA had 100% sensitivity, specificity, and accuracy. Nano dot-ELISA assays have higher specificity, sensitivity, and accuracy than traditional ELISAs in detecting A. veronii. Further studies are needed to develop a rapid test kit for on-site field diagnosis.
Topics: Animals; Aeromonas veronii; RNA, Ribosomal, 16S; Silver; Aeromonas hydrophila; Enzyme-Linked Immunosorbent Assay; Gram-Negative Bacterial Infections; Fish Diseases
PubMed: 37451347
DOI: 10.1016/j.mimet.2023.106782 -
Microbial Pathogenesis Jun 2020Aeromonas veronii is a widely distributed novel pathogen that can affect humans and animals, it can cause sepsis in fish with high mortality and serious economic losses...
Alteration of the gut microbiome and immune factors of grass carp infected with Aeromonas veronii and screening of an antagonistic bacterial strain (Streptomyces flavotricini).
Aeromonas veronii is a widely distributed novel pathogen that can affect humans and animals, it can cause sepsis in fish with high mortality and serious economic losses to aquaculture. In the study, the gut microbiome of the infected and uninfected grass carp with Aeromonas veronii were analyzed probiotics and pathogenic bacteria by the Miseq high-throughput sequencing, the results showed that the infected fish were significantly higher in Proteobacteria, Firmicutes, Fusobacteria, and the immune factors in liver and kidney were up-regulated by qRT-PCR. In order to effectively inhibit the pathogen, we screened an actinomycete strain and had good antibacterial effect on Aeromonas veronii. The new antagonistic bacteria was named as Streptomyces flavotricini X101, the whole genome sequencing revealed that the metabolic process was most active. After grass carp was inoculated with the minimum inhibitory concentration of 900 μg/mL of the strain's fermentation supernatant, then Aeromonas veronii was injected, we found that the pathological symptoms such as body surface, anus and abdominal congestion were alleviated by H&E staining. Cellular experiments showed that it wasn't toxic to liver cells of grass carp. Overall, this is the first study of changes in intestinal flora, phenotype, and immune factors in grass crap infected with Aeromonas veronii, it had important theoretical significance and application value for immunization and prevention.
Topics: Aeromonas veronii; Animals; Carps; Fish Diseases; Gastrointestinal Microbiome; Gram-Negative Bacterial Infections; High-Throughput Nucleotide Sequencing; Immunoglobulin M; Interleukins; RNA, Ribosomal, 16S; Real-Time Polymerase Chain Reaction; Streptomyces
PubMed: 32145322
DOI: 10.1016/j.micpath.2020.104092 -
Fish & Shellfish Immunology Jun 2022Aeromonas veronii is a freshwater bacterium associated with many diseases in aquatic animals. However, few cases of A. veronii infection were reported in Odontobutis...
Aeromonas veronii is a freshwater bacterium associated with many diseases in aquatic animals. However, few cases of A. veronii infection were reported in Odontobutis potamophila, which has been becoming a promising fish species in China in recent years. In this study, the dominant bacteria were isolated from diseased O. potamophila showing signs of hemorrhage on fins, ulceration on the dorsal and abdomen. The representative isolate Stl3-1was identified as A. veronii based on analysis of its morphological, physiological, and biochemical features, as well as 16S rRNA and gyrB gene sequences. The median lethal dosage (LD) of the isolate Stl3-1 for O. potamophila was determined as 4.5 × 10 CFU/mL. Histopathological analysis revealed that the isolate Stl3-1caused considerable histological lesions in the fish, including tissue cell degeneration, necrosis, and inflammatory cell infiltrating. Detection of virulence-related genes showed that A. veronii Stl3-1 was positive for exu, ompA, lip, flaH, hlyA, aer, flgM, tapA, act, flgA, gcaT and flgN. Additionally, quantitive real-time PCR (qRT-PCR) was also undertaken to analyses the host defensive response in O. potamophila infected by A. veronii. The immune-related gene expressions in O. potamophila during experimental infection were monitored at different point of time, and the results showed that the expression levels of MHC II, Myd88, TLR, and SOD were significantly up-regulated in liver, gill, spleen, and head kidney. The results revealed that A. veronii was a pathogen causing mass mortalities of O. potamophila and will contribute to better understanding the host defensive response against A. veronii infection.
Topics: Aeromonas; Aeromonas veronii; Animals; Fish Diseases; Fishes; Gram-Negative Bacterial Infections; Immunity; Perciformes; RNA, Ribosomal, 16S; Virulence
PubMed: 35561950
DOI: 10.1016/j.fsi.2022.05.009 -
Surgical Infections Oct 2021
Topics: Aeromonas; Aeromonas caviae; Aeromonas veronii; Cholecystitis, Acute; Gram-Negative Bacterial Infections; Humans
PubMed: 33533674
DOI: 10.1089/sur.2020.474