血流感染中大肠埃希菌的药物敏感性、耐药基因及同源性分析

摘要：目的 分析血流感染中大肠埃希菌的药物敏感性、耐药基因分布及菌株间的同源性特征，为控制医院内感染，指导 临床合理用药提供依据。方法 连续收集2019年10月至2020年9月山西省人民医院住院患者血培养中的大肠埃希菌，用基质辅 助激光解析电离飞行时间质谱仪进行菌种鉴定，用VITEK-2进行药敏试验，PCR方法检测超广谱β-内酰胺酶(ESBLs)耐药基因， 采用多位点序列分型(Multilocus Sequence Typing，MLST)对菌株进行同源性分析。结果 76株大肠埃希菌对氨苄西林的耐药率 最高，达到90.7%，其次是环丙沙星、头孢唑林、左氧氟沙星和头孢曲松，耐药率分别为69.7%、65.7%、63.1%和56.5%。对哌 拉西林/他唑巴坦、厄他培南、亚胺培南、阿米卡星和替加环素全部敏感。产ESBLs大肠埃希菌的检出率为56.5%。共检出blaTEM, blaCTX-M和blaOXA-1 3种ESBLs基因，其中blaCTX-M为主要基因型。最常见的ST型为ST131(19.7%，15/76)、ST69(15.7%，12/76)和 ST38(7.8%，6/76)。结论 本院大肠埃希菌对大多数常用抗生素具有耐药性，治疗大肠埃希菌引起的血流感染，可经验性选择 碳青霉烯类、哌拉西林/他唑巴坦、阿米卡星和替加环素。我院主要流行的ESBLs基因型为blaCTX-M型，同源性分析表明，菌株间 存在遗传多样性。

Drug sensitivity,drug resistance genes and homology analysis of Escherichia coli in bloodstream infection

Abstract Objective To analyze the drug sensitivity, drug resistance gene distribution and homology characteristics of Escherichia coli in bloodstream infection, so as to provide basis for controlling nosocomial infection and guiding clinical rational drug use. Methods Escherichia coli in blood culture of inpatients in Shanxi people's Hospital from October 2019 to September 2020 were collected continuously. The strains were identified by matrix assisted laser desorption ionization time of flight mass spectrometer and the drug sensitivity was tested by VITEK-2. The extended-spectrumbeta-lactamases (ESBLs) resistance gene was detected by polymerase chain reaction (PCR), and the homology of the strain was analyzed by MLST. Results The highest resistance rate of 76 strains of Escherichia coli to ampicillin was 90.7%, followed by ciprofloxacin, cefazolin, levofloxacin and ceftriaxone, and the drug resistance rates were 69.7%, 65.7%, 63.1% and 56.5%, respectively. All of them were sensitive to piperacillin/ tazobactam, ertapenem, imipenem, amikacin and tegacyclin. The detection rate of ESBLs producing Escherichia coli was 56.5%. Three ESBLs genes group blaTEM, blaCTX-M and blaOXA-1 were detected, of which blaCTX-M was themain genotype. The most common sequence types were ST131 (19.7%，15/76)、ST69 (15.7%，12/76) and ST38 (7.8%, 6/76). Conclusion The results showed that the Escherichia coli in our hospital was resistant to most common antibiotics, and it was found that carbapenems, piperacillin tazobactam, amikacin and tegacyclin could be selected empirically. The main prevalent resistant genotype was blaCTX-M, and homology analysis showed genetic diversity among the