Virulence gene detection of Vibrio parahaemolyticus in 3 food poisoning events

Objective To isolate pathogenes from stool samples of patients and other samples collected from food-processing tools in 3 food poisoning events,and identify the type and virulence gene of pathogens isolated. MethodsSuspect pathogen was isolated and identified in accordance with National Standard GB/T 4789-2003 and GB/T 4789.7 -2008;The detected Vibrio parahaemolyticus was tested for species-specific gene (320 bp),thermostable direct hemolysin gene (tdh 434 bp),tdh-related hemolysin gen (trh 250 bp) by PCR and thermolabile hemolysin gene (tlh 229 bp) by LAMP. Results Seven strains of V. parahaemolyticus was detected in 27 samples collected from patients,cooks and processing tools in 3 food poisoning events,including 6 strains from stool samples of patients and 1 strains from samples of processing tools. The serotype of 7 isolated V. parahaemolyticus strains were O10∶K66,O2∶K3,O1∶K33。 The isolates in each food poisoning events had the same biological characteristics,serotype and drug susceptibility test result and emerged Kanagawa phenomenon (KP),similar species-specific gene Vp bands were detected in tlh virulence genes,but the tdh,trh genes were negative. Conclusion It was confirmed the 3 food poisoning events were caused by the pollution of different serotype V. parahaemolyticu of tlh+/tdh-/trh-.