Comparison of Molecular Methods for Typing Vibrio parahaemolyticus

An outbreak of Vibrio parahaemolyticus gastroenteritis on Canada’s west coast in 1997 emphasized the need to develop molecular methods for differentiation and typing of these organisms. Isolates were analyzed by enterobacterial repetitive intergenic consensus sequence (ERIC) PCR, detection of restriction fragment length polymorphisms (RFLP) in rRNA genes (ribotyping), pulsed-field gel electrophoresis (PFGE), and RFLP analysis of the genetic locus encoding the polar flagellum (Fla locus RFLP analysis). ERIC PCR and ribotyping were the most informative typing methods, especially when used together, while Fla locus RFLP analysis was the least discriminatory. PFGE exhibited good discrimination but suffered from a high incidence of DNA degradation. ERIC PCR and ribotyping will be useful for the evaluation of genetic and epidemiological relationships among V. parahaemolyticus strains.