Phenotypic and molecular characteristics of Vibrio parahaemolyticus associated with acute diarrhea in Ningbo,Zhejiang province,China

Objective To understand the distribution and molecular characteristics of Vibrio parahaemolyticus in the patients with acute diarrhea of Ningbo district for prevention and control of V. parahaemolyticus infection. Methods The feces samples were collected from the patients with acute diarrhea during April to October,2012. The isolates of V. parahaemolyticus were detected for serotyping and identifying the virulence genes,tlh,tdh and tdh. Molecular characteristics were analyzed by using multi-locus sequence typing( MLST). Results Among the 962 feces samples 71( 7. 38%) were V. parahaemolyticus-positive. The 71 strains belonged to 17 different serotypes. O3: K6 was the predominant serotype accounting for 61. 97%( 44 strains),followed by O∶ K8( 5 strains). Tlh gene was presented in all the examined strains and tdh gene was positive in 70 strains( 98. 59%). Only three strains were trh-positive.MLST analysis showed 13 sequence types( STs) were foundin the 71 V. parahaemolyticus strains,and ST3 was the predominant type accounted for 63. 38%( 45 strains). Conclusion O3∶ K6 serotype was the most prevalent type of V. parahaemolyticus in Ningbo district. ST3 was the master sequence type.