Characterisation of pathogenic Vibrio spp. isolated from live Pacific abalone (Haliotis discus hannai Ino, 1953) marketed in South Korea

Abstract

This study aimed to evaluate the profile of virulence factors and antimicrobial resistance in Vibrio spp. isolated from live Pacific abalone (Haliotis discus hannai Ino, 1953) marketed in South Korea. A total of 32 Vibrio isolates comprising V. alginolyticus (n=15), V. diabolicus (n=14), V. antiquarius (n=2) and V. parahaemolyticus (n=1) were  analysed. All isolates demonstrated DNase, lipase, phospholipase and amylase activities. Additionally, production of slime (97%), gelatinase (94%), α-haemolysin (22%), β-haemolysin (78%) and protease (53%) were detected. Virulence genes viz., toxR, tlh, tdh, VAC, VPI, ctxAB and hupO were recorded in 56, 59, 13, 100, 41, 9 and 9% of the isolates, respectively. All isolates were resistant to ampicillin and 88% of the isolates were resistant to cephalothin and colistin sulphate. Twentyone isolates (66%) showed multiple antimicrobial resistance (MAR) index ≥0.2. Antimicrobial resistance genes blaCTX (85%), blaTEM (10%), blaSHV (10%), strAB (13%) and aphA-IAB (22%) and class 1 integrons (19%) were detected. V. diabolicus and V. antiquarius were identified and characterised for the first time in the Pacific abalone. Our findings imply the significance of integrated monitoring and surveillance programmes for the occurrence, virulence, and antimicrobial resistance patterns of vibrios in Pacific abalone.

Keywords: Haliotis discus hannai, Pacific abalone, Pathogenicity, South Korea, Vibrio spp., virulence