Pathogenic characteristics of Vibrio parahaemolyticus isolated from foodborne diseases in Guangzhou,2010—2013

Objective To study the serotypes,antimicrobial resistance,virulence genes and molecular characteristics of Vibrio parahaemolyticus isolated from foodborne diseases during 2010—2013 in Guangzhou. Methods A total of108 Vibrio parahaemolyticus strains isolated from foodborne diseases were collected to serotype and antimicrobial resistance tests. PCR was used for the detection of tdh( thermostable direct hemolysin gene) and trh( tdh-related hemolysin gene). All the samples were analyzed by pulsed- field gel electrophoresis( PFGE). Results A total of 108 strains of Vibrio parahaemolyticus obtained from diarrhea patients with foodborne diseases were collected,among which O3: K6( 51,47. 2%) and O1: KUT( 32,29. 6%) were the dominant serotypes. Vibrio parahaemolyticus isolated showed high resistance to ampicillin( 90. 7%) and cefepime( 28. 8%),but were 100. 0% sensitive to cotrimoxazole and chloramphenicol.Multi- drug resistance was revealed in 53. 6%( 15 /28),20. 6%( 7 /34),18. 8%( 3 /16) and 33. 3%( 10 /30) of isolated strains in 2010,2011,2012 and 2013,respectively. Results from virulence gene detection suggested that 95. 4%( 103 /108) isolates belonged to tdh+trh-,while 4. 6%( 5 /108) isolates belonged to tdh-trh+. Results from PFGE analysis suggested that 108 isolates were discriminated into 3 clusters and 55 different PFGE patterns with the similarity value between 60. 2% and 100. 0%. The dominant serotype O3: K6 and O1: KUT seemed to gather in the cluster II,while serotype O4: K8 in cluster Ⅲ. Conclusion O3: K6 and O1: KUT are the dominant serotypes in Vibrio parahaemolyticus strains isolated from foodborne diseases during 2010—2013 in Guangzhou. These strains show high sensitivity to most antibiotics,but with multi- drug resistance. Positive rate of tdh gene is high. PFGE analysis reveals genetic diversity is within the Vibrio parahaemolyticus strains of foodborne diseases in Guangzhou.