广州市腹泻病例中沙门菌的耐药性及分子特征

Molecular typing and drug resistance of Salmonella from diarrheal patients in Guangzhou

目的分析2019年广州市腹泻病例中沙门菌的耐药情况和分子特征,为沙门菌疾病的防控提供科学依据。方法对从7家定点监测医院分离到的沙门菌株进行血清分型、药物敏感性试验和脉冲场凝胶电泳(PFGE),并使用国家致病菌识别网的比对功能进行同源性分析。结果共收集到沙门菌株303株,其中56.44%(171/303)的菌株血清型为1,4,[5],12:i:-,其次为肠炎沙门菌11.22%(34/303),斯坦利沙门菌4.29%(13/303)和伦敦沙门菌3.96%(12/303)。所分离到的菌株对氨苄西林和四环素耐药的比例分别为87.79%(266/303)和87.13%(264/303),并且有90.76%(275/303)的菌株对3种以上抗生素耐药。PFGE聚类分析发现,1,4,[5],12:i:-沙门菌各型别之间差异较大,相似度为42.97%~100.00%;肠炎沙门菌各型别之间差异较小,相似度为75.05%~100.00%。结论广州市腹泻病例中的沙门菌血清型主要为1,4,[5],12:i:-;多重耐药菌占比较高;PFGE型别呈多样性,不同血清型菌株的基因相似度有较大差异。

Objective To understand the molecular types and drug resistance of Salmonella isolated from diarrhea cases in Guangzhou during 2019 and provide scientific basis for early prevention,control and tracing of Salmonella infection.Methods The serotypes,drug sensitivity and pulse-field gel electrophoresis(PFGE)type of all the stains of Salmonella isolated from 7 designated hospitals were detected.Homology analysis was performed using the comparison function of the Chinese Pathogen Identification Net.Results A total of 303 strains with accurate serotype detection were collected,of which 56.44%(171/303)were Salmonella;Salmonella 1,4,[5],12:i:-was the dominant serotype.Other serotypes with higher proportions were S.enteritidis 11.22%(34/303),S.stanley 4.29%(13/303)and S.London 3.96%(12/303).Through antibiotic resistance test,it was found that the highest resistance were ampicillin(87.79%)and tetracycline(87.13%),and 90.76%of the strains were resistant to more than 3 antibiotics.PFGE cluster analysis showed that Salmonella 1,4,[5],12:i:-isolates were significant differences between each other,with a similarity of 42.97%-100.00%.There were few differences among S.enteritidis,and the similarity was 75.05%-100.00%.Conclusions Salmonella 1,4,[5],12:i:-was the dominant serotype causing infectious diarrhea in Guangzhou city.The proportion of multi-drug-resistant(MDR)strains was high.PFGE types were diverse,and the genetic similarities of strains of different serotypes varied greatly.