耐碳青霉烯肺炎克雷伯菌的耐药基因分析

Analysis of drug resistance genes in carbapenem-resistant Klebsiella pneumoniae

目的分析耐碳青霉烯肺炎克雷伯菌的耐药情况及其耐药基因,为该菌感染的治疗和预防提供参考。方法收集临床分离非重复耐碳青霉烯肺炎克雷伯菌50株,采用VITEK-2 compact全自动微生物鉴定药敏分析仪进行常规药敏试验,改良碳青霉烯灭活试验(mCIM)检测碳青霉烯酶,乙二胺四乙酸(EDTA)协同法检测金属酶,PCR扩增和基因测序技术检测其耐药基因。结果药敏结果显示,肺炎克雷伯菌对碳青霉烯类、青霉素类、头孢菌素类及氨曲南等抗生素的耐药率高达80%以上。50株耐碳青霉烯肺炎克雷伯菌中,mCIM试验结果阳性37株,其中EDTA协同试验阳性有3株。PCR结果显示,37株mCIM试验阳性耐碳青霉烯肺炎克雷伯菌中,检测出33株KPC-2型耐药基因,未检测出IMP、VIM、NDM-1、OXA-48等耐药基因。结论耐碳青霉烯肺炎克雷伯菌对常用抗生素表现出高水平耐药,耐药机制主要为产碳青霉烯酶,耐药基因型主要以KPC-2型为主。

Objective To investigate the drug resistance of carbapenem-resistant Klebsiella pneumoniae and its drug resistance genes, and provide basis for clinical prevention and treatment. Methods 50 strains of carbapenem-resistant Klebsiella pneumoniae were collected. Antimicrobial susceptibility was done by VITEK-2 automatic bacterium identifying and drug sensitivity analyzing systems. Modified carbapenem inactivation method（mCIM） and test for detection of metallo-beta- lactamases（MBL） were used to detect carbapenemase phenotype. Polymerase chain reaction（PCR） was used to amplify carbapenemase gene. Results The sensitivity test showed that the resistance rates of Klebsiella pneumoniae to carbapenems, penicillins, cephalosporins and aztreonam were more than 80%. 37 strains were positive in the mCIM for detecting carbapenemase phenotype. 3 strains were positive in the test for detection of metallo-beta-lactamases（MBL）. 33 strains were determined to contain KPC - 2 gene, without the other carbapenemase genes. Conclusions The carbapenem-： Klebsiella pneumoniae showed high resistance to commonly used antimicrobial agents. Producing carbapenemase was the major mechanisms of carbapenem-resistant Klebsiella pneumoniae, which mainly produced KPC-2 gene.