社区获得性尿路感染中产超广谱β内酰胺酶菌株分子流行病学研究

Extended-spectrum beta-lactamases produced by bacteria in community-acquired urinary tract infections:A molecular epidemiology study

目的调查2013年1-8月同济医院门诊尿路感染中产超广谱β内酰胺酶（ESBLs）的大肠埃希菌和肺炎克雷伯菌的耐药性及耐药机制。方法采用琼脂稀释法检测100株菌对19种抗菌药物的最低抑菌浓度;对ESBLs阳性菌株进行ESBLs基因、Amp-C酶基因、质粒介导的喹诺酮耐药基因及16SrRNA甲基化酶基因进行测定。结果细菌ESBLs的发生率为57%,所有菌株对亚胺培南、美罗培南及粘菌素均敏感;ESBLs阳性菌对19种抗生素的耐药率为0~100%,ESBLs阴性菌为0~48.8%;在57株ESBLs阳性菌株中,CTX-M-14型33株,CTX-M-15型26株,TEM-1型28株,OXA-1型8株,SHV-11型与SHV-12型各1株;Amp-C酶基因阳性菌中DHA-1型2株,CMY-2型2株;质粒介导的喹诺酮耐药基因阳性菌中aac（6′）-Ib-cr型32株,qnrB型4株;16SrRNA甲基化酶基因阳性菌中rmtB型3株,armA型1株。结论 CTX-M型、TEM型以及aac（6′）-Ib-cr型是同济医院社区获得性尿路感染中产ESBLs菌株的主要流行基因型。

Objective To investigate the resistance and the mechanism of resistance of Escherichia colt and Klebsiella pneumoniae that were collected from Jan to Aug 2013 in outpatients from Tongji Hospital. Methods The agar dilution method was used to determine the minimum inhibitory concentrations of 19 drugs for 100 strains. ESBL genes, Amp C genes, and PMQR genes were genotyped and 16S rRNA was detected in ESBL-producing strains. Results Of the strains examined, 57% produced ESBLs. All of the strains were sensitive to imipenem, meropenem, and polymyxin. ES-BL-producing strains had significantly higher resistance to 19 drugs than did non-ESBL-producing strains, with resistance ranging from 0-100% for the former and 0-48.8% for the latter. The genotype of the 57 ESBL-producing strains was CTM-M-14 for 33 strains, CTM-M-15 for 26 strains, TEM-1 for 28 strains, OXA-1 for 8 strains, SHV-11 for 1 strain, and SHV-12 for 1 strain. The Amp-C genotype was DHA-1 for 2 strains and CMY-2 {or 2 strains. The PMQR genotype was aac （6＇）-Ib-cr for 32 strains and qnrB for 4 strains. The 16S rRNA genotype was rmtB for 3 strains and armA for 1 strain. Conclusion This study has indicated that CTX-M, TEM, and aac （6＇）-Ib-cr are the predominant genotypes of ESBL-producing bacteria responsible for community-acquired urinary tract infections.