2016—2021年无锡市副溶血性弧菌毒力基因和耐药性分析及分子分型研究

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

目的分析2016—2021年无锡市不同来源副溶血性弧菌的毒力基因、耐药性和分子分型结果。方法采用多重荧光PCR、微量肉汤稀释法、脉冲场凝胶电泳(PFGE)分别对204株分离自无锡市各类监测样本中的副溶血性弧菌进行tlh/tdh/trh毒力基因检测、耐药试验和分子分型。数据比较采用χ^(2)检验。结果204株菌tlh基因携带率为100%(204/204),tdh基因携带率为82.35%(168/204),trh基因携带率为2.45%(5/204),食品及环境分离株与病患分离株tdh基因携带率差异具有统计学意义(P<0.001)。菌株对头孢唑啉耐药率最高达96.08%(196/204),对3种及以上抗菌药物的耐药率为2.94%(6/204),食品及环境分离株与病患分离株对氨苄西林、四环素、磺胺甲唑/甲氧苄啶、环丙沙星耐药率差异具统计学意义(P<0.05);204株副溶血性弧菌经过聚类分析,分为123个PFGE带型,相似度49.1%~100.0%,按85%的相似度聚类可分为18个带型簇。结论无锡市副溶血性弧菌病患分离株大部分携带tdh基因;菌株对头孢唑啉耐药率最高;PFGE型别呈多态性,优势带型不明显。

Objective The 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.Methods Multiplex 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.χ^(2) tests were used for statistical analysis.Results Among 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.Conclusion Most 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.