Genetic heterogeneity among Vibrio alginolyticus strains, and design of a PCR-based identification method using gyrB gene sequence.

Vibrio alginolyticus, a pathogen among humans and marine animals, is ubiquitous in marine environments. The aims of this study were to analyze the relationships between genetic diversity and origins, and to develop new primers based on the gyrB sequence to identify V. alginolyticus isolated from various sources. To determine the genetic diversity of this bacterium, an arbitrarily primed polymerase chain reaction (AP-PCR) technique was performed on 36 strains of V. alginolyticus isolated from diarrhea patients and from diseased marine animals and environments in southern Thailand. The results showed distinct DNA fingerprints of all strains, indicating that they are genetically heterogeneous. For species-specific identification of V. alginolyticus, primers targeting the gyrB gene of V. alginolyticus were developed. Thirty reference Vibrio spp., 13 non-Vibrio spp., and 160 strains of V. alginolyticus isolated from various sources in southern Thailand were used to evaluate the specificity of these primers. Our results showed that the gyrB primers could specifically identify V. alginolyticus from all sample types. In addition, the detection limit of the PCR was at least 95 pg of DNA template. Therefore, we concluded that the newly designed gyrB primers are rapid, highly sensitive, and specific to identify V. alginolyticus isolated from various sources.