不同测试方法检测产IMP酶肺炎克雷伯菌对碳青霉烯类抗菌药物的耐药性

Different testing methods detecting drug resistance of klebsiella pneumoniae producing IMP enzyme to carbapenem antibiotic

目的：评价临床常用的3种药敏方法对产IMP酶肺炎克雷伯菌耐药性的检出率，比较FDA与CLSI折点对判定结果的影响。方法：选取2010年6月-2013年6月临床分离的42株经PCIK证实产IMP酶的肺炎克雷伯菌，以纸片扩散法、Etest法及VITEK2系统检测各菌株对碳青霉烯类抗菌药物的耐药率，比较FDA与CLSIM100-S22折点对耐药率的影响，FDA折点判读结合改良Hodge试验（MHT）分析。结果：依照FDA折点，纸片扩散法、Etest法及VITEK2系统检测厄他培南耐药率分别为95．2％（40株）、100％（42株）和100％（42株），亚胺培南耐药率分别为76．2％（32株）、83．3％（35株）和90．5％（38株），纸片扩散法和Etest法检测美罗培南耐药率分别为73．8％（31株）和83．3％（35株）；依照CLSIM100-S22折点，纸片扩散法、Etest法及VITEK2系统检测厄他培南耐药率分别为90．5％（38株）、100％（42株）和100％（42株），亚胺培南耐药率分别为54．8％（23株）、59．5％（25株）和61．9％（26株），纸片扩散法和EteSt法检测关罗培南耐药率分别为57．1％（24株）和61．9％（26株）。结论：厄他培南作为筛选产IMP酶肺炎克雷伯菌的指示药物优于其他药物，FDA标准结合MHT比CLSI标准更能检出菌株产IMP酶情况，VITEK2系统能更好地检出IMP酶介导的碳青霉烯类抗菌药物的耐药性。

Objective ： To evaluate three susceptibility methods on detecting of carbapenem resistance in IMP-producing Klebsiella pneumonia, and compared FDA and CLSI breakpoints for determining outcomes. Methods ： Forty-two Klebsiella pneumoniae producing IMP carbapenemase were isolated from June 2010 to June 2013 which were confirmed by PCR, carbapenem resistance in IMP-producing Klebsiella pneumoniae were detected by the disk diffusion method, Etest method and VITEK 2 system, then comparaed FDA and CLSI M100-S22 breakpoint on the impact of drug resistance, FDA breakpoint interpretation was analysised by combining modified Hodge test （MHT）.Results ： According to FDA breakpoints, the resistance rates of ertapenem detected by disk diffusion method, Etest method and the VITEK 2 system were 95.2% （40 isolates）, 100% （42 isolates） and 100% （42 isolates）, the resistance rates of imipenem were 76.2% （32 isolates）, 83.3% （35 isolates） and 90.5% （38 isolates）, the resistance rates of meropenmn detected by disk diffusion method and Etest method were 73.8% （31 isolates） and 83.3 % （35 isolates）. According to CLSI M100-S22 breakpoints, the resistance rates of ertapenem detected by disk diffusion method, Etest method and the VITEK 2 system were 90.5% （38 isolates）, 100% （42 isolates） and 100% （42 isolates）, the resistance rates of imipenem were 54.8% （23 isolates）, 59.5% （25 isolates） and 61.9% （26 isolates）, the resistance rates ofmeropenem detected by disk diffusion method and Etest method were 57.1% （24 isolates） and 61.9 % （26 isolates）. Conclusions ： Ertapenem was a more sensitive indicator than meropenem and imipenem as screening IMP possessing isolates. Combined with FDA standards and MHT was better than the CLSI standard to detect Klebsiella pnemnoniac producing IMP carbapenemase of sensitivity of VITEK 2 system was higher than other methods in identification of IMP-mediated carbapenem resistance.