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Antonie Van Leeuwenhoek Dec 2023Naturally infected Channa punctata exhibiting bacterial septicemic syndrome including ulcerations along with mortality records were collected from a fish farm in Assam...
Naturally infected Channa punctata exhibiting bacterial septicemic syndrome including ulcerations along with mortality records were collected from a fish farm in Assam during winter season (early November 2020 to early January 2021). The moribund fishes were subjected for bacterial isolation followed by identification of the bacteria. Two dominant emerging bacterial pathogens were identified as Aeromonas veronii (isolate ZooGURD-01) and Aeromonas hydrophila (isolate ZooGURD-05) by standard biochemical characterization and 16S rRNA and rpo B gene amplification. Re-infection experiments of both the bacterial isolates in healthy disease-free C. punctata showed similar symptoms to that of natural infection thus confirming their virulence. The LD calculated during challenge test for both the isolates ZooGURD-01 and ZooGURD-05 found to be pathogenic at 2.6 × 10 and 1.6 × 10 CFU/fish respectively. Further PCR amplification of specific virulent genes (aerolysin, hemolysin and enterotoxin) confirmed pathogenicity for both isolates. Histopathological examinations of liver and kidney in re-infection experiments showed prominent changes supporting bacterial septicaemia. Antibiotic sensitivity pattern showed that the isolates ZooGURD-01 and ZooGURD-05 were sensitive to 22 and 19 out of 25 antimicrobials respectively. The present study was the first report on the mortality of farmed C. punctata associated with natural infection caused by A. veronii and A. hydrophila with no record of pathogenicity of A. veronii in C. punctata.
Topics: Animals; Channa punctatus; Aeromonas hydrophila; Aeromonas veronii; RNA, Ribosomal, 16S; Reinfection; Fishes
PubMed: 38153571
DOI: 10.1007/s10482-023-01896-z -
Fish & Shellfish Immunology Feb 2024CD4-1 found in bony fish contains four extracellular immunoglobulin (Ig)-like domains similar to that of mammalian CD4, which is crucial for the activation of CD4 helper...
CD4-1 found in bony fish contains four extracellular immunoglobulin (Ig)-like domains similar to that of mammalian CD4, which is crucial for the activation of CD4 helper T-cell. However, there is limited knowledge regarding the molecular markers, immune functions and regulation mechanism of CD4-1 in teleosts due to their vast diversity. In this study, we cloned and characterized two isoforms of Qihe crucian carp CD4-1, designated as CaCD4-1.1 and CaCD4-1.2. We further explored their expression responses upon stimulation with Aeromonas veronii, and the regulation of their immune responses against A. veronii by NF-κB. The ORF of CaCD4-1.1 and CaCD4-1.2 cDNA encoded 477 and 466 amino acids, respectively. Both proteins contained seven conserved cysteine residues in the extracellular domain, and a CCC motif in their cytoplasm, respectively. However, CaCD4-1.1 exhibited a relatively limited similarity with CaCD4-1.2 in the ectodomain. The quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that the mRNA expression of CaCD4-1.1 and CaCD4-1.2 exhibited differential constitutive expression across all examined tissues. Furthermore, the expression level of CD4-1.2 was higher than that of CD4-1.1 in the gills, head kidney, and spleen of Qihe crucian carp subjected to A. veronii challenge, while it was lower in the trunk kidney. Inhibition of NF-κB activity resulted in a decrease in the expression levels of CD4-1.1 and CD4-1.2 mRNA in the gill, while inducing an increase in expression levels in the spleen, in accordance with the observed ultrastructural changes in both organs. Interestingly, the impact of NF-κB on the mRNA expression level of CD4-1.1 appears to be stronger than that of CD4-1.2. Our results suggest that CaCD4-1.1 and CaCD4-1.2 could be expressed on T cells and antigen-sampling cells that exhibit similar characteristics to mammalian M cells, respectively, and differentially regulated by NF-κB in adaptive immune responses against bacterial infection. This research contributes to a better understanding of the crucial role of CD4-1 in the immune response of Qihe crucian carp and provide novel insights for the prevention and treatment of fish diseases in aquaculture.
Topics: Animals; Goldfish; Carps; NF-kappa B; Aeromonas veronii; Immunity, Innate; RNA, Messenger; Fish Diseases; Fish Proteins; Aeromonas hydrophila; Gram-Negative Bacterial Infections; Mammals
PubMed: 38142019
DOI: 10.1016/j.fsi.2023.109318 -
Protein Expression and Purification Mar 2024Aeromonas veronii is an emerging bacterial pathogen that causes serious systemic infections in cultured Nile tilapia (Oreochromis niloticus), leading to massive deaths....
Aeromonas veronii is an emerging bacterial pathogen that causes serious systemic infections in cultured Nile tilapia (Oreochromis niloticus), leading to massive deaths. Therefore, there is an urgent need to identify effective vaccine candidates to control the spread of this emerging disease. TonB-dependent receptor (Tdr) of A. veronii, which plays a role in the virulence factor of the organism, could be useful in terms of protective antigens for vaccine development. This study aims to evaluate the potential use of Tdr protein as a novel subunit vaccine against A. veronii infection in Nile tilapia. The Tdr gene from A. veronii was cloned into the pET28b expression vector, and the recombinant protein was subsequently produced in Escherichia coli strain BL21 (DE3). Tdr was expressed as an insoluble protein and purified by affinity chromatography. Antigenicity test indicated that this protein was recognized by serum from A. veronii infected fish. When Nile tilapia were immunized with the Tdr protein, specific antibody levels increased significantly (p-value <0.05) at 7 days post-immunization (dpi), and peaked at 21 dpi compared to antibody levels at 0 dpi. Furthermore, bacterial agglutination activity was observed in the fish serum immunized with the Tdr protein, indicating that specific antibodies in the serum can detect Tdr on the bacterial cell surface. These results suggest that Tdr protein has potential as a vaccine candidate. However, challenging tests with A.veronii in Nile tilapia needs to be investigated to thoroughly evaluate its protective efficacy for future applications.
Topics: Animals; Aeromonas veronii; Cichlids; Immunization; Recombinant Proteins; Vaccines, Subunit; Fish Diseases
PubMed: 38104792
DOI: 10.1016/j.pep.2023.106412 -
Fish & Shellfish Immunology Jan 2024Bacterial infection is considered one of the major issues in fish culturing that results in economic losses. Metal nanoparticles are a cutting-edge and effective disease...
Nelumbo nucifera synthesized selenium nanoparticles modulate the immune-antioxidants, biochemical indices, and pro/anti-inflammatory cytokines pathways in Oreochromis niloticus infected with Aeromonas veronii.
Bacterial infection is considered one of the major issues in fish culturing that results in economic losses. Metal nanoparticles are a cutting-edge and effective disease management and preventive strategy because of their antibacterial ability. In this investigation, the selenium nanoparticles were prepared by a biological method using Nelumbo nucifera leaves extract. The in-vitro antibacterial activity of N. nucifera synthesized selenium nanoparticles (NN-SeNPs) was tested against Aeromonas veronii. A treatment assay was conducted on 210 Oreochromis niloticus (average body weight: 27 ± 2.00 g). A preliminary approach was conducted on 90 fish for determination of the therapeutic concentration of NN-SeNPs which was found to be 4 mg/L. Fish (n = 120) were categorized into four groups for 10 days; G (control) and G (NN-SeNPs) were non-challenged and treated with 0 and 4 mg/L NN-SeNPs, respectively. While, G and G were infected with 2 × 10 CFU/mL of A. veronii and treated with 0 and 4 mg/L NN-SeNPs, respectively. NN-SeNPs exhibited an inhibition zone against A. veronii with a diameter of 16 ± 1.25 mm. The A. veronii infection increased the hepato-renal biomarkers (alanine and aspartate aminotransferases and creatinine) than the control group. An oxidative stress was the consequence of A. veronii infection (higher malondialdehyde and hydrogen peroxide levels with lower glutathione peroxidase superoxide, dismutase, and catalase activity). A. veronii infection resulted in lower immunological biomarker values (immunoglobulin M, lysozyme, and complement 3) with higher expression of the inflammatory cytokines (interleukin-1β and tumor necrosis factor-ɑ) as well as lower expression of the anti-inflammatory cytokines (interleukin-10 and transforming growth factor-β). Therapeutic application with 4 mg/L NN-SeNPs prevented the disease progression; and modulated the hepato-renal function disruptions, oxidant-immune dysfunction, as well as the pro/anti-inflammatory cytokines pathway in the A. veronii-infected fish. These findings suggest that NN-SeNPs, employed as a water therapy, can safeguard fish from the harmful effects of A. veronii and serve as a promising antibacterial agent for sustainable aquaculture.
Topics: Animals; Antioxidants; Selenium; Aeromonas veronii; Cytokines; Nelumbo; Diet; Cichlids; Anti-Inflammatory Agents; Nanoparticles; Metal Nanoparticles; Anti-Bacterial Agents; Fish Diseases; Animal Feed
PubMed: 38092091
DOI: 10.1016/j.fsi.2023.109287 -
Fish Physiology and Biochemistry Apr 2024In the aquaculture industry, silica nanoparticles (SiNPs) have great significance, mainly for confronting diseases. Therefore, the present study aims to assess the...
Silica nanoparticles alleviate the immunosuppression, oxidative stress, biochemical, behavioral, and histopathological alterations induced by Aeromonas veronii infection in African catfish (Clarias gariepinus).
In the aquaculture industry, silica nanoparticles (SiNPs) have great significance, mainly for confronting diseases. Therefore, the present study aims to assess the antibacterial efficiency of SiNPs as a versatile trial against Aeromonas veronii infection in African catfish (Clarias gariepinus). Further, we investigated the influence of SiNPs in palliating the immune-antioxidant stress biochemical, ethological, and histopathological alterations induced by A. veronii. The experiment was conducted for 10 days, and about 120 fish were distributed into four groups at random, with 30 fish each. The first group is a control that was neither exposed to infection nor SiNPs. The second group (SiNPs) was vulnerable to SiNPs at a concentration of 20 mg/L in water. The third group was experimentally infected with A. veronii at a concentration of 1.5 × 10 CFU/mL. The fourth group (A. veronii + SiNPs) was exposed to SiNPs and infected with A. veronii. Results outlined that A. veronii infection induced behavioral alterations and suppression of immune-antioxidant responses that appeared as a clear decline in protein profile indices, complement 3, lysozyme activity, glutathione peroxidase, and total antioxidant capacity. The kidney and liver function biomarkers (creatinine, urea, alkaline phosphatase, and alanine aminotransferase) and lipid peroxide (malondialdehyde) were substantially increased in the A. veronii group, with marked histopathological changes and immunohistochemical alterations in these tissues. Interestingly, the exposure to SiNPs resulted in a clear improvement in all measured biomarkers and a noticeable regeneration of the histopathological changes. Overall, it will establish that SiNPs are a new, successful tool for opposing immunological, antioxidant, physiological, and histopathological alterations induced by A. veronii infection.
Topics: Animals; Antioxidants; Aeromonas veronii; Catfishes; Oxidative Stress; Immunosuppression Therapy; Biomarkers
PubMed: 38060081
DOI: 10.1007/s10695-023-01274-6 -
Microbial Pathogenesis Jan 2024The global ornamental fish trade carries important risk factors for spreading pathogens between different countries and regions, not only for ornamental fish but also...
The global ornamental fish trade carries important risk factors for spreading pathogens between different countries and regions, not only for ornamental fish but also for cultured fish and even other animal species. In the current study, we reported the capacity of Aeromonas veronii and A. hydrophila isolated from ornamental fish to experimentally infect the reared Amazonian fish Colossoma macropomum. For this, those bacteria were identified, and a primary characterization was performed. Fish were inoculated with 0.1 mL of increasing concentrations of A. hydrophila or A. veronii (C1 = 1 × 10; C2 = 1.8 × 10; C3 = 2.1 × 10; C4 = 2.4 × 10 bacterial cells per mL) in the coelomic cavity. In the control group, fish received the same volume of sterile saline solution (0.9 %). Fish presented petechiae, skin suffusions, and mortality rates up to 100 % according to the inoculum concentration. Histopathologically, fish presented necrosis with karyolysis, loss of the cytoplasmic delimitation of cells of the renal tubules and hepatocytes, hemorrhage, cellular edema, and the presence of bacterial cells. The LD of A. veronii on C. macropomum was estimated at 2.4 × 10 CFU mL and of A. hydrophila at 1.408 × 10 CFU mL. The results demonstrated that it is possible that Aeromonas species isolated from ornamental fish affect C. macropomum, causing similar clinical signs and lesions. This shows the importance of promoting risk control measures worldwide regarding the trade of ornamental fish.
Topics: Animals; Aeromonas; Characiformes; Aeromonas veronii; Lethal Dose 50; Risk Factors; Fish Diseases; Gram-Negative Bacterial Infections
PubMed: 38048837
DOI: 10.1016/j.micpath.2023.106461 -
BMC Veterinary Research Nov 2023This study (60 days) was conducted to investigate the ability of diet enriched with Coriandrum sativum powder or its extract to protect Oreochromis niloticus health and...
The contribution of Coriandrum sativum in enhancing Oreochromis niloticus rearing at sub-optimal temperatures: effect on growth, health status, survival rate, and resistance to Aeromons Veronii.
This study (60 days) was conducted to investigate the ability of diet enriched with Coriandrum sativum powder or its extract to protect Oreochromis niloticus health and survivability at suboptimal temperature (21 ℃). One hundred and twenty (33.14 ± 0.5 g) were divided into four groups; each group has three replicates.. The first control group fed on a basal diet. Second and third groups fed on diet enriched with 30 mg/kg coriander seed powder (CP) and coriander seed ethanolic extract (CE), respectively. The fourth group (OT) fed on diet enriched with 500 mg oxytetracycline/kg diet. The results revealed that CE exhibited a considerable improvement in hematological parameters, hepatic-renal functions, antioxidant status, and immunological markers as well as remarkably increased resistance against Aeromonas veronii. It could be concluded that feeding tilapia CE enriched diet at 30 mg/kg is a recommended strategy to enhance tilapia health and resistance to A. veronii infection reared at 21 ℃.
Topics: Animals; Cichlids; Coriandrum; Survival Rate; Powders; Temperature; Diet; Health Status; Animal Feed; Fish Diseases; Dietary Supplements; Disease Resistance; Gram-Negative Bacterial Infections
PubMed: 38037033
DOI: 10.1186/s12917-023-03809-8 -
Journal of Applied Microbiology Dec 2023Motile Aeromonas septicaemia (MAS) caused by motile Aeromonas species is an important disease in farmed freshwater fish due to intensification of culture and improper...
AIMS
Motile Aeromonas septicaemia (MAS) caused by motile Aeromonas species is an important disease in farmed freshwater fish due to intensification of culture and improper farm practices. This study characterized and profiled motile Aeromonas species recovered from clinically sick tilapia farmed in the Philippines, with a view to identifying targeted disease prevention and control measures against MAS in farmed tilapia species.
METHODS AND RESULTS
Sixteen isolates from diseased farmed Nile tilapia were identified as Aeromonas veronii (n = 14), Aeromonas caviae (n = 1), and Aeromonas dhakensis (n = 1). Five biochemical profiles using API 20E were exhibited by the A. veronii strains giving an unreliable identification. A high level of agreement was observed in identifying the Aeromonas strains using 16S rRNA and rpoD gene sequencing, although the latter has a higher discriminatory value. Three or more virulence genes dominated by cytotoxic enterotoxin act and aerolysin aer were detected. Different genotypes based on virulence gene clustering suggested varied mechanisms used by Aeromonas to colonize and infect or to mutualistically co-exist with the fish. Acquired multiple antibiotic resistance was found in a single A. veronii isolate. All were susceptible to enrofloxacin, oxolinic acid, florfenicol, and chloramphenicol. Tetracycline and sulfonamide resistances and class 1 integron were detected in three A. veronii isolates.
CONCLUSION
Several strains of motile aeromonads, especially A. veronii, which have varied genotypes based on virulence, biochemical profile, and antibiotic resistance, are involved in MAS in natural disease outbreaks in farmed Nile tilapia in the Philippines.
Topics: Animals; Cichlids; RNA, Ribosomal, 16S; Philippines; Aeromonas; Anti-Bacterial Agents; Fish Diseases; Gram-Negative Bacterial Infections
PubMed: 38012120
DOI: 10.1093/jambio/lxad279 -
Microorganisms Oct 2023is the causative agent of septicemia in fish, and it is associated with significant economic losses in the aquaculture industry. While piscine infections are mainly...
is the causative agent of septicemia in fish, and it is associated with significant economic losses in the aquaculture industry. While piscine infections are mainly treated with antibiotics, the emergence of resistance in bacterial populations requires the development of alternative methods of treatment. The use of phages can be one of them. A novel jumbo phage, AerS_266, was isolated and characterized. This phage infects only mesophilic strains and demonstrates a slow lytic life cycle. Its genome contains 243,674 bp and 253 putative genes: 84 encode proteins with predicted functions, and 3 correspond to tRNAs. Genes encoding two multisubunit RNA polymerases, chimallin and PhuZ, were identified, and AerS_266 was thus defined as a phiKZ-like phage. While similar phages with genomes >200 kb specific to and have been previously described, AerS_266 is the first phiKZ-like phage found to infect .
PubMed: 38004661
DOI: 10.3390/microorganisms11112649 -
Pathogens (Basel, Switzerland) Nov 2023We studied the phenotypic and genomic characteristics related to the virulence and antibiotic resistance of two strains, which were co-isolated before an outbreak of...
We studied the phenotypic and genomic characteristics related to the virulence and antibiotic resistance of two strains, which were co-isolated before an outbreak of among diseased seabass on Agathonisi Island, Greece, in April 2015. The first strain, AG2.13.2, is a potentially pathogenic mesophilic variant of , and the second, AG2.13.5, corresponds to an related to KN-Mc-11N1 with an ANI value of 97.32%. AG2.13.2 lacks the type III secretion system just like other mesophilic strains of . This characteristic has been associated with lower virulence. However, the genome of AG2.13.2 contains other important virulence factors such as type II and type VI secretion systems, and toxins such as , aerolysin /, and different types of hemolysins. The strain also carries several genes associated with antibiotic resistance such as the efflux pump, and exhibits resistance to tetracycline, ampicillin, and oxolinic acid. In an in vivo challenge test with gilthead seabream larvae, the bv strain AG5.28.6 exhibited the highest virulence among all tested strains. Conversely, both and showed minimal virulence when administered alone. Interestingly, when bv AG5.28.6 was co-administered with , the larvae survival probability increased compared to those exposed to bv AG5.28.6 alone. This finding indicates an antagonistic interaction between bv AG5.28.6 and AG2.13.5. The co-administration of bv AG5.28.6 with did not yield distinct survival probabilities. Our results validate that the primary pathogen responsible for European seabass aeromoniasis is bv .
PubMed: 38003801
DOI: 10.3390/pathogens12111337