Research – Putative virulence traits and antibiogram profile of Aeromonas spp. isolated from frozen white‐leg shrimp (Litopenaeus vannamei) marketed in Korea

Wiley Online

We evaluated 44 strains of Aeromonas spp. consisting of five species; A. hydrophila, A. veronii, A. caviae, A. enteropelogenes, and A. media isolated from frozen white‐leg shrimp marketed in Korea. All the isolates were positive in DNase, protease, gelatinase, and lipase tests whereas 29 isolates (66%) were positive for slime production. Ten virulence genes were detected by PCR in which the prevalence of act, alt, ast, aerA, lip, ahyB, ser, fla, gcat, and ascV were 50%, 77%, 72%, 82%, 84%, 93%, 80%, 64%, 84%, and 23%, respectively. As observed in antibiogram, 100% resistance was detected in ampicillin and clindamycin while nalidixic acid, tetracycline, cephalothin, erythromycin, and trimethoprim‐sulfamethoxazole were resisted by 95%, 89%, 86%, 68%, and 66% of the isolates, respectively. Multiple antibiotic resistance index was >0.20 in 42/44 (95%) of the isolates. Overall, our results indicated that these aeromonads are indicative of a serious public health risk due to their virulence potential and the multiple‐antimicrobial resistance.

Practical applications

Similar to other seafood, shrimp have been identified as vehicles of Aeromonas spp. which are the etiological agents of many foodborne infections. The gyrB gene sequencing and phylogenetic analysis confirmed the occurrence of five species of Aeromonas in frozen white‐leg shrimp marketed in Korea. Putative virulence properties were examined by both phenotypic tests and PCR assays whereby majority of the isolates exhibited the virulence both phenotypically and genetically. Besides, the disc diffusion test was carried out to assess the antibiotic susceptibility of the isolates. Following the results, the MAR index was calculated for each strain thereby suggested their high risk owing to MAR indices higher than 0.20. With our results, frozen white‐leg shrimp associated Aeromonas spp., exhibiting potential virulence and antimicrobial resistance, can be considered as a potential public health risk. Moreover, it is noteworthy that freezing the shrimp may not reduce the incidence of pathogenic Aeromonas.

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