ABSTRACT
Vibrio parahaemolyticus, found frequently in oysters, is the most prevalent gastroenteritis-causing pathogen in Korea and in several other Asian countries. This study monitored changes in the environmental parameters and occurrence of V. parahaemolyticus in oyster aquaculture sites. Of the 44 presumed V. parahaemolyticus isolates obtained, when tested against 16 antibiotics, 90.9, 86.4, and 75.0% of the 44 isolates exhibited resistance to vancomycin, ampicillin, and streptomycin, respectively. PCR analysis for the presence of the toxR gene confirmed 31 of the 44 isolates as being positive V. parahaemolyticus strains. The toxR positive isolates were tested for the presence of thermostable direct hemolysin (tdh) and tdh-related hemolysin (trh) virulence genes. Only 9.1% toxR positive isolate exhibit the trh gene and none of the isolates were tested positive for tdh. The occurrence of multi drug resistance strains in the environment could be an indication of excessive usage of antibiotics in agriculture and aquaculture fields.
Subject(s)
Drug Resistance, Bacterial , Ostreidae/microbiology , Vibrio parahaemolyticus/drug effects , Vibrio parahaemolyticus/genetics , Animals , Anti-Bacterial Agents/pharmacology , Aquaculture , Asia , Bacterial Toxins/genetics , Genes, Bacterial , Hemolysin Proteins/genetics , Polymerase Chain Reaction , Republic of Korea , Shellfish , Vibrio parahaemolyticus/pathogenicity , Virulence , Virulence Factors/geneticsABSTRACT
Pathogenic Vibrio alginolyticus, a cause of severe infection in shellfish, as well as in humans, has been found at high frequency around all coastal areas of Korea. The aim of this study was to determine the occurrence of V. alginolyticus, to identify the strains isolated from oysters in West Sea, and to investigate their antimicrobial resistance profiles. Biochemical analyses of the 90 initially recovered presumptive V. alginolyticus colonies indicated that 16 isolates were V. alginolyticus. PCR analysis to detect the presence of the gyrB gene confirmed that 15 (93.8 %) of the 16 isolates were V. alginolyticus. These 15 isolates had the following profiles of resistance against 16 antibiotics: all isolates were resistant to ampicillin and vancomycin, and 26.7 % of the isolates exhibited resistance to cephalothin. A large number of isolates showed intermediate resistance to erythromycin (100 %) and rifampin (73.3 %). Five (33.3 %) of the V. alginolyticus isolates demonstrated multiple resistance to at least three antimicrobials.
