MTS法与仪器MIC法检测耐碳青霉烯类肺炎克雷伯菌对替加环素敏感性的差异

摘要

目的 了解耐碳青霉烯类肺炎克雷伯菌(CRKP)临床分布特点,分析菌株产酶情况及验证替加环素的体外抗菌活性.方法 分析某院2015年1-12月临床患者送检标本中分离的53株CRKP的药敏结果,对目标菌株进行改良Hodge试验检测碳青霉烯酶,同时采用EDTA协同试验检测金属β-内酰胺酶,使用MIC测试条(MTS)确认仪器MIC法中替加环素药敏结果.结果 53株CRKP科室分布主要为重症监护病房(ICU)14株,占26.42％,烧伤科13株(24.53％);标本来源主要为痰23株(43.40％),创面分泌物15株(28.30％);年龄分布主要为≥60岁患者,检出35株(66.04％).CRKP对替加环素的敏感率最高(96.2％).经改良Hodge试验确认有48株产碳青霉烯酶,阳性率90.6％,同时15株产金属β-内酰胺酶.仪器MIC法判读为替加环素耐药的菌株经MTS法验证后均应判读为敏感.结论 该院CRKP主要产碳青霉烯酶,其中部分菌株可产2类不同的β-内酰胺酶;替加环素在药敏试验中对CRKP具有良好的抗菌活性,经仪器MIC法检测为替加环素耐药的菌株须进行MTS法确认.%Objective To explore clinical distribution characteristics of carbapenem-resistant Klebsiella pneumoniae (CRKP), analyze enzyme production of strains and verify the in vitro antimicrobial activity of tigecycline.Methods Antimicrobial susceptibility testing results of 53 strains of CRKP isolated from clinical specimens of patients in a hospital from January to December 2015 were analyzed, carbapenemase production of target strains was detected by modified Hodge test, metallo-β-lactamase was detected by EDTA synergy test, minimum inhibitory concentration(MIC) of tigecycline susceptibility testing result detected by instrument was confirmed by MIC test strip(MTS method).Results 53 CRKP strains were mainly isolated from patients in intensive care unit (n=14, 26.42％) and burn unit(n=13, 24.53％);sputum(n=23, 43.40％) and wound secretion(n=15, 28.30％) were the main specimen sources;isolation rate of CRKB was highest in the elderly≥60 years old, 35 strains(66.04％)of CRKP were isolated.CRKP was most sensitive to tigecycline(96.2％).The modified Hodge test showed that 48 strains(90.6％) produced carbapenemases and 15 strains produced metallo-β-lactamase.MICs of tigecycline-resistant strains detected by instrument were all confirmed as susceptibility by MTS.Conclusion CRKP mainly produce carbapenems in this hospital, some strains can produce two types of different β-lactamases;antimicrobial susceptibility testing showed that tigecycline has good antimicrobial activity against CRKP, tigecycline-resistant strains detected by instrument must be confirmed by MTS method.