Analysis of the drug resistance, virulence gene and molecular typing of Vibrio parahaemolyticus identified from patients in Zaozhuang City, 2019-2020

Abstract

ObjectiveThe study aims to analyze the drug resistance, virulence genes and molecular typing of Vibrio parahaemolyticus (VP) identified in Zaozhuang from 2019 to 2020.MethodsThe VP strains were isolated and identified, following the Vibrio parahaemolyticus test protocol in the National Food Safety Standard (GB 4789.7—2013). The broth microdilution method was performed to determine the resistance of VP to 12 antibiotics. Their virulence genes (tlh, tdh, trh) were detected by real-time quantitative polymerase chain reaction (PCR). Pulsed field gel electrophoresis (PFGE) was applied for molecular typing, and the strain clustering was analyzed by BN software. The chi-square test was used to analyze the statistical result (α=0.05).ResultsThe detection rate of VP was 4.57% out of 678 patients’ stool samples. Among the 31 identified VP strains, the resistance rate to cefazolin was 58.06%, and the multi-drug resistance rate was 12.90%. The positive rates of virulence genes tlh, tdh, trh were 100%, 96.78%, 3.22% respectively. The 31 VP strains were further divided into 17 band types and 2 band clusters. The dominant band type cluster covered 93.55% of the strains.ConclusionThe VP strains in Zaozhuang from 2019 to 2020 were highly resistant to cefazolin. Some strains showed multiple drug resistance. They mainly carry two virulence genes, tdh and tlh. The PFGE bands were well-clustered, suggesting high homology among these VP strains. Epidemiological investigation and tracing of VP strains should be strengthened in this region.

Keywords

• vibrio parahaemolyticus
• drug sensitive test
• virulence gene
• molecular typing