[The infection and molecular characteristics of Vibrio parahaemolyticus isolated from intestinal outpatient in two sentinel hospitals in Shanghai, 2010-2012].

Objective: To analyze virulence genes and molecular characteristics of Vibrio parahaemolyticus isolated from sporadic cases with diarrhea in tow sentinel hospitals of Shanghai, 2010-2012.

Methods: A total of 2 729 stool samples were collected from two surveillance sentinel hospitals in Shanghai 2010-2012. Vibrio parahaemolyticus strains were isolated and identified from diarrhea out patients using TCBS agar plates and biochemical reactions. Thermostable direct hemolysingene (tdh), thermostable-related hemolysin gene (trh), hemolysin gene (tlh) were detected by multiplex PCR method. Isolates were analyzed by PFGE and MLST. The PFGE profiles were analyzed using BioNumerics software.

Results: A total of 30 clinical Vibrio parahaemolyticus strains isolated from 2 729 stool samples. The anually Vibrio parahaemolyticus isolation rate during 2010 to 2012 were 1.1%(11/973), 1.0%(11/1 120) and 1.3%(8/636) respectively. The PCR positive rates of virulence genes tlh, tdh and trh were 100%, 97% and 0 respectively. The Vibrio parahaemolyticus strains were divided into 13 PFGE types (P1-P13)and 3 ST types (ST-189, ST-799, ST-3). Among 13 PFGE types, P4 was the main PFGE type, accounting for 30%(9/30). P9, P10 were accounting for 12% (4/30) respectively, P1, P2, P12, P13 were accounting for 7%(2/30) respectively, the others types were 3%(1/30) respectively. MLST analysis results showed there are three ST types, ST3 was 84%(25/30), ST189 and ST799 were accounting for 13% (4/30) and 3% (1/30) respectively.

Conclusion: The infection rate of Vibrio parahaemolyticus was not very high from 2010-2012 in Shanghai, all strains were positive for tlh and negative for trh. ST3 was the major type of Vibrio parahaemolyticus.