Virulence genes, antibiotic resistance, and molecular typing study of Vibrio parahaemolyticus in Wuxi City from 2016 to 2021

Abstract

ObjectiveThe aim of this study was to analyze the virulence genes， antibiotic resistance， and molecular typing of Vibrio parahaemolyticus （V.parahaemolytics） isolates from multiple sources in Wuxi City between 2016 and 2021.MethodsMultiplex real-time PCR， microbroth dilution， and pulsed field gel electrophoresis （PFGE） were used to detect virulence genes （tlh/tdh/trh）， evaluate antibiotic resistance， and perform molecular typing of 204 V. parahaemolyticus strains isolated from various surveillance samples in Wuxi City. χ2 tests were used for statistical analysis.ResultsAmong the V. parahaemolyticus isolates， the prevalence of tlh， tdh， and trh was 100% （204/204）， 82.35% （168/204）， and 2.45% （5/204）， respectively. A significant difference was found in the prevalence of tdh between food/environmental sources and patient-source isolates （P < 0.001）. Most （96.08%， 196/204） isolates were resistant to cefazolin， and 2.94% （6/204） of the isolates displayed a multidrug resistance pattern （resistant to three or more drugs）. Strains from both food/environmental and patient sources were significantly （P < 0.05） resistant to ampicillin， tetracycline， methomyl/sulfamethoxazole， and ciprofloxacin. The 204 V. parahaemolyticus strains were clustered into 123 PFGE band types with 49.1%-100.0% similarity， which could be differentiated into 18 different genetic clusters with 85% similarity.ConclusionMost V. parahaemolyticus isolates from patient sources in Wuxi City harbored the tdh gene. The isolated V. parahaemolyticus strains showed the highest resistance to cefazolin. The PFGE types were polymorphic， and no major bands were found.

Keywords

• vibrio parahaemolyticus
• virulence gene
• microbial susceptibility test
• molecular typing