Molecular characterisation of a multidrug resistance conjugative plasmid from Vibrio parahaemolyticus.

Vibrio parahaemolyticus is a major causative agent of gastroenteritis and is the leading cause of food-borne illness in Hong Kong. Recent studies of resistance to extended-spectrum β-lactams and fluoroquinolones in V. parahaemolyticus have caused huge concern. This work reports the characterisation of a multidrug resistance conjugative plasmid in V. parahaemolyticus isolated from shrimp samples from Hong Kong. The plasmid is ca. 200 kb and carries multidrug resistance genes, including a novel plasmid-mediated quinolone resistance gene qnrVC6 surrounded by several known and novel insertion sequence (IS) elements, an extended-spectrum β-lactamase gene bla(PER-1) mediated by ISCR1, and a ca. 3-kb four-gene cassette (aacA3, catB2, dfrA1 and aadA1) class 1 integron. Transmission of this multidrug resistance conjugative plasmid among Vibrio spp. would compromise the effectiveness of Vibrio infection control and pose a huge threat to public health.