江苏省无锡市门诊腹泻患者鼠伤寒沙门菌分子分型和耐药特征研究

目的 了解无锡市腹泻病例分离的鼠伤寒沙门菌分子分型和耐药特征。方法 对无锡市2016—2017年哨点医院分离的26株鼠伤寒沙门菌采用微量肉汤稀释法测定菌株对9类14种抗菌药物的敏感性；选择两株多重耐药的菌株（SM699：耐7类；SM912：耐4类）进行全基因组二代测序，用生物信息学方法研究其耐药的遗传学基础和多位点序列分型；采用脉冲场凝胶电泳（PFGE）分析菌株同源性。结果 26株鼠伤寒沙门菌对亚胺培南均敏感，对其他13种抗菌药物呈现不同程度的耐药（3.8%～65.4%）。耐药率排在前3位的为四环素（65.4%,17/26）、氨苄西林（61.5%,16/26）、萘啶酸（42.3%,11/26）。20株菌至少对1类及以上抗菌药物耐药（76.9%,20/26），共产生15种耐药表型，有14株菌为多重耐药菌株（53.8%,14/26）。全基因组二代测序结果表明，SM699和SM912分别携带23种和9种耐药基因，可介导对相应抗菌药物的耐药，耐药基因与耐药表型基本一致。菌株SM699的gyrA基因突变可介导喹诺酮类耐药。两株菌均为ST34型，属于近缘克隆株。26株菌产生23种PFGE带型，相似...

Molecular types and drug resistant characteristics of Salmonella Typhimurium from outpatientswith diarrhea in Wuxi,Jiangsu

  Objective  To understand the molecular types and drug resistance characteristics of Salmonella typhimurium Typhimurium isolated from diarrhea cases in Wuxi city.   Methods  The antimicrobial susceptibility of 26 Salmonella Typhimurium strains isolated from sentinel hospitals in Wuxi city from 2016 to 2017 was determined by broth microdilution methodto 14 antibiotics. Two multidrug-resistant strains (SM699: resistant to 7 types of antibiotic; SM912: resistant to 4 types of antibiotic) were selected for whole-genome sequencing, and the genetic basis of drug resistance and multilocus sequence typing (MLST) were studied by bioinformatics methods. The homology of strain was analyzed by pulse field gel electrophoresis (PFGE).   Results  26 Salmonella Typhimurium strains were sensitive to imipenem and showed different degrees of resistance (3.8%?65.4%) to 13 other antibiotics. The drug resistance rates oftetracycline (65.4%, 17/26), ampicillin (61.5%, 16/26) and nalidixicacid (42.3%, 11/26) occupied the top three. Twenty strains (76.9%, 20/26) were resistant to at least one class of antibiotics, with a total of 15 drug-resistant phenotypes, and 14 strains (53.8%, 14/26) were multi-drugresistant strains. The second generation sequencing results showed that SM699 and SM912 carried 23 and 9 resistance genes, respectively, which mediated drug resistance to the corresponding antibiotics. The resistance genes and drug resistance phenotypes were basically consistent. In addition, one point mutationin gyrA of SM699 was found to mediate quinolone resistance. Both strains were ST34 and belonged to the same clone. PFGE showed that 26 strains weredividedinto 23 bands, with the similarity between 58.6%?100.0%.   Conclusion  The drug resistance of Salmonella Typhimurium in Wuxi wasserious. In order to provide a basis for better prevention strategies, weshould continuously strengthen the monitoring of drug resistance, and further study was needed to clarify the mechanism of drug resistance gene acquisition.