Isolation, Molecular Characterization, and Antibiotic Susceptibility of Vibrio parahaemolyticus in Korean Seafood

Abstract

The principal objective of this study was to investigate the incidence, risk assessment, antibiotic resistance, and genotyping of Vibrio parahaemolyticus in Korean seafood. The incidence of V. parahaemolyticus in seafood obtained from several fish markets in Korea was investigated from May to December of 2009, except between July and September. Two selective mediums (TCBS [thiosulfate, citrate, bile salts, and sucrose] agar and CHROMagar (TM) Vibrio) were used, and the V. parahaemolyticus strains were identified via polymerase chain reaction (PCR) amplification (Vp. flaE, tl, and toxR). 16S rRNA gene sequencing and their virulence were analyzed via the detection of tdh, trh, ORF8, toxRS/old, and toxRS/new genes. We collected 24 strains of V. parahaemolyticus: 19 seafood isolates, three environmental isolates, and two clinical (human) isolates. Among these strains, two tdh+ strains, two ORF8+ strains, 16 toxRS/old+ strains, and one toxRS/new+ strain were isolated. Twenty-two commercial antibiotics were used to assess the antibiotic susceptibility of isolates, and all the strains evidenced resistance to more than four antibiotics. The strains harboring antibiotic-resistant genes such as TetA (25%) and strB (4.16%) were detected via PCR. Repetitive extragenic palindromic sequence (REP)-PCR analysis revealed differences in the V. parahaemolyticus strains from other species and intraspecific strains.