襄阳市腹泻患者肠炎沙门菌分子特征及耐药表型分析

Molecular characteristics and drug resistance phenotype of Salmonella enteritidis in patients with diarrhea in Xiangyang

目的研究分析襄阳市腹泻患者肠炎沙门菌分离株的血清型、耐药情况与分子分型特征。方法对2019—2020年腹泻患者肠炎沙门菌株开展血清分型、药物敏感试验、脉冲场凝胶电泳(PFGE)分型、全基因组测序分析。结果药敏结果显示该地区肠炎沙门氏菌呈现出不同程度的耐药性,其中94.7%的肠炎沙门菌株为多重耐药菌株。肠炎沙门菌PFGE电泳图谱经聚类分析显示,19株菌可分为6种PFGE带型,其中流行优势型包含12株菌。MLST分型显示,15株菌均为ST11型,均携带多重耐药基因(mdsA、mdsB、mdsC、gols、sdiA)及MdtK基因,均携带各种侵袭力相关毒力基因,但不同菌株间所携带的致病岛分泌系统相关毒力基因略有差别。系统进化发育树分析结果显示15株菌可分成2个不同进化分支。结论襄阳地区肠炎沙门菌多重耐药状况较为严重,存在优势PFGE带型和ST型,并且携带多重耐药基因及多种侵袭力相关毒力基因。

Objective To study the serotype,drug resistance,and molecular typing characteristics of Salmonella enteritidis strains isolated from patients with diarrhea in Xiangyang City.Methods Serotyping,drug sensitivity test,pulsed field gel electrophoresis(PFGE)typing,and whole genome sequencing were carried out on Salmonella enteritidis strains isolated from diarrhea patients from 2019 to 2020.Results From the drug susceptibility test,Salmonella enteritidis in this region showed varying degrees of drug resistance,with 94.7%of Salmonella enteritidis strains being multidrug-resistant.The PFGE electrophoretogram of Salmonella enteritidis showed that 19 strains could be divided into 6 PFGE types by cluster analysis,among which 12 strains belonged to the epidemic dominant type.MLST typing showed that all 15 strains were ST11 type,carrying multiple drug resistance genes(mdsA,mdsB,mdsC,gols,and sdiA)and mdtK gene,and all carried various invasiveness-related virulence genes.However,there were slight differences in virulence genes related to the secretion system of the pathogenic island among the different strains.The phylogenetic tree analysis of the system evolution showed that 15 strains could be divided into 2 different evolutionary branches.Conclusion The situation of multidrug resistance in Salmonella enteritidis in Xiangyang is serious,with dominant PFGE types and ST types,and it carries multiple drug resistance genes and various invasiveness-related virulence genes.