Establishment of multiple-locus variable number tandem repeat analysis assay for Vibrio parahaemolyticus isolated in China

ObjectiveTo establish a multiple-locus variable number tandem repeat analysis (MLVA) assay for Vibrio parahaemolyticus isolated in China.

MethodsA total of 420 V. parahaemolyticus strains isolated from different areas in China were used. The 12 variable-number tandem-repeat (VNTR) loci were amplified by PCR and the amplicons were analyzed by capillary electrophoresis. The discriminatory power of different VNTR locus and combinations of VNTR loci were evaluated.

ResultsThe amplification rates of the 12 VNTR loci of V. parahaemolyticus were different. Locus VP1-17 showed no polymorphism (Nei value＝0.00), locus VP2-03 showed low polymorphism (Nei value＝0.10) and locus VP2-07 showed highest polymorphism. Locus VPTR7 could only be amplified in 71.90% of the test strains. The 420 V. parahaemolyticus strains could be divided into 311 MLVA types using the 6-locus (VP1-10, VPTR1, VPTR3, VPTR5, VPTR6, and VPTR8) .

ConclusionThe established 6-locus MLVA scheme showed satisfactory discriminatory power and economic significance and thus is suitable for the molecular typing of V. parahaemolyticusstrains isolated in China.