Outcome of co-infection with opportunistic and multidrug resistant Aeromonas hydrophila and A. veronii in zebrafish: Identification, characterization, pathogenicity and immune responses. Issue 80 (September 2018)

• Record Type: Journal Article
• Authors: Chandrarathna, H.P.S.U.; Nikapitiya, Chamilani; Dananjaya, S.H.S.; Wijerathne, C.U.B.; Wimalasena, S.H.M.P.; Kwun, Hyo Jung; Heo, Gang-Joon; Lee, Jehee; De Zoysa, Mahanama
• Is Part Of: Fish & shellfish immunology. Issue 80(2018)
• Page Start: 573
• Page End: 581
• Publication Date: 2018-09
• Subjects: Aeromonas hydrophila -- Aeromonas veronii -- Co-infection -- Multidrug resistant bacteria -- Zebrafish -- Immune responses; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2018.06.049
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: Fish can be potentially co-infected by two or more bacterial strains, which can make synergistic influence on the virulence of infection. In this study, two opportunistic and multidrug resistant Aeromonas strains were isolated from wounds of morbid zebrafish with typical deep skin lesions similar to Motile Aeromonas Septicemia. Isolates were genetically identified as A. hydrophila and A. veronii by 16 S rRNA sequencing and phylogenetic analysis. Both isolates were positive for virulent genes (aerA, lip, ser, exu gcaT) and selected phenotypic tests (DNase, protease, gelatinase, lipase, biofilm production and β-haemolysis). A. hydrophila and A. veronii had strong antibiotic resistance against ampicillin, tetracycline, nalidixic acid, kanamycin, erythromycin, clindamycin and trimethoprim-sulfamethoxazole. Histopathological studies revealed that co-infection causes severe necrosis and hypertrophy in the muscles, kidney and liver of zebrafish. Naturally co-infected zebrafish showed highly induced tnf-α, il-1β, il-6, il-12, ifn, ifn-γ, cxcl1 8 b and ccl34a.4 at transcription level compared to healthy fish, suggesting virulence factors may activate immune and inflammatory responses of zebrafish. Experimentally infected zebrafish showed significantly higher mortality under co-infection with A. hydrohila and A. veronii (87%), followed by individual challenge of A. hydrophila (72%) or A. veronii (67%) suggesting that virulence of A. hydrophila have greater pathogenicity than A. veronii during co-infection. Highlights: Aeromonas hydrophila and A. veronii from wounds of morbid zebrafish showed highly resistant to antibiotics. Naturally co-infected zebrafish showed highly induced TNF-α, IL-1β, IL-12 and IFN-γ transcription. Virulence of A. hydrophila has greater effect than A. veronii during artificial co-infection.