碳青霉烯类抗生素耐药的肺炎克雷伯菌IMP型金属β-内酰胺酶研究

Study on IMP Metallo-β-Lactamase in Carbapenem-Resistant Klebsiella pneumoniae

目的:探讨肺炎克雷伯菌产金属酶的临床分离情况并对产金属酶菌株进行耐药性分析,为临床合理选用抗菌药物提供依据。方法:收集2009年1月—2009年10月天津医科大学总医院142株临床分离肺炎克雷伯菌,通过改良Hodge试验、改良三维试验检测其碳青霉烯酶,乙二胺四乙酸(EDTA)协同试验检测金属酶,PCR法扩增金属酶基因,用纸片法和VITEK2-Compact全自动微生物分析仪进行药物敏感性试验。结果:142株肺炎克雷伯菌中,通过改良Hodge试验、改良三维试验检测出2株产碳青霉烯酶菌株,这2株菌通过EDTA协同试验检测为阳性,提示这2株菌产金属酶经PCR证实为产IMP型金属酶,MIC方法显示2株产金属酶的菌株对氨曲南敏感,而对青霉素类、头孢菌素类耐药,κ-B法检测显示碳青霉烯类抗菌药物耐药。结论:天津地区已出现产金属酶肺炎克雷伯菌,该酶是引起肺炎克雷伯菌耐碳青霉烯类抗生素的主要原因。

Objective：To investigate metallo-β-lactamases（MBL）and resistance of Klebsiella pneumoniae clinical isolates,providing the basis for the rational use of antimicrobial drugs.Methods：One hundred and forty-two clinical strains of Klebsiella pneumoniae were collected from January to October 2009 in General Hospital of Tianjin Medical University.The modified Hodge test and the modified three-dimensional test were used to co-detect carbapenemase.Ethylenediaminetetraacetic acid（EDTA）-disk synergy test was used to detect MBL.The MBL encoding genes were amplified by PCR.Drug sensitivity test was performed by Kirby-Bauer method and VITEK2-Compact system.Results：Two carbapenemase-producing strains were found in 142 clinical strains of Klebsiella pneumoniae by using the modified Hodge test and the modified three-dimensional test.EDTA-disk synergy test showed positive,suggesting MBL-producing of these 2 strains.PCR result indicated that the two strains carried IMP genes.MIC indicated that aztreonam was sensitive to the Klebsiella pneumoniae MBL-producing strains,but penicillins,and cephalosporins antibiotics were resistant carbapenem was resistant by κ-B method.Conclusion：Metallo-β-lactamases in Klebsiella pneumoniae was detected in Tianjin.The production of enzyme is the main mechanisms of carbapenem-resistant in Klebsiella pneumoniae.