耐药阴沟肠杆菌一线抗菌药物耐药基因及菌株亲缘性研究

Drug resistance genes to first-line antimicrobial agents and phylogenetics of drug-resistant Enterobacter cloacae

目的调查耐药阴沟肠杆菌中抗菌药物耐药基因元件的携带状况,以及菌株间的亲缘关系。方法收集2016年1月-12月湖州市第一人民医院患者分离的20株耐药阴沟肠杆菌,用Kirby-Bauer法检测对11种抗生素的敏感性;用聚合酶链反应(PCR)及序列分析的方法分析β-内酰胺类耐药基因、氨基糖苷类耐药基因、喹诺酮类耐药基因。耐药基因经测序后作BLAST比对。对耐药结果作样本聚类分析(UPGMA法)。结果 20株阴沟肠杆菌对β-内酰胺类药物除亚胺培南、美罗培南外均为耐药,7株对氨基糖苷类与喹诺酮类药物耐药。20株菌共检出2种β-内酰胺酶类耐药基因、4种氨基糖苷类耐药基因、3种喹诺酮类耐药基因。样本聚类分析显示,20株菌可分为A与B二群。A群共有16株,呈明显的聚集性,其中12株疑似克隆传播。B群又可分为B-a和B-b二个亚群,但无疑似克隆传播。结论本组20株阴沟肠杆菌携带耐药基因是对β-酰胺类、氨基糖苷类、喹诺酮类产生耐药的重要原因,且基因型与耐药表型对应。本组菌检出的12株菌疑似克隆传播。

OBJECTIVE To investigate the drug resistance genes in a group of 20 strains of Enterobacter cloacae and analyze the phylogenetics of the strains.METHODS Totally 20 strains of drug-resistant E.cloacae were isolated from the patients who were treated in Huzhou First Hospital from Jan 2016 to Dec 2016,the drug susceptibility to11 types of antibiotics was determined by using Kirby-Bauer method,the resistance genes toβ-lactams,aminoglycosides and quinolones were analyzed by means of polymerase-chain-reaction(PCR)and sequencing analysis,the sequenced drug resistance genes were compared by using BLAST,and sample cluster analysis was performed for the result of drug susceptibility testing by means of UPGMA.RESULTS The 20 strains of Ec.loacae were resistant to all of theβ-lactams except for imipenem and meropenem,and 7 strains were resistant to aminoglycosides and quinolones.Totally 2 types ofβ-lactamases resistance genes,4 types of aminoglycosides resistance genes and 3 types of quinolones resistance genes were detected in the 20 strains.The sample cluster analysis showed that the20 strains could be divided into the cluster A and B,and cluster A consisted of 16 strains,showing remarkable aggregation,12 of which showed suspected clonal spread.The cluster B could be divided into subgroup B-a and Bb,however,there was no suspected clonal spread.CONCLUSIONCarrying with the drug resistance genes in the 20 strains of Ec.loacae is the leading cause of the resistance toβ-lactams,aminoglycosides and quinolones,and the genotypes are corresponding to the drug resistance phenotypes.The 12 isolated strains show the suspected clonal spread.