ICU和非ICU患者感染肺炎克雷伯菌中超广谱β-内酰胺酶和碳青霉烯酶检测

Detection of extended-spectrumβ-lactamses and carbapenemases in Klebsiella pneumoniae causing infections in ICU patients and non-ICU patients

目的比较分析医院ICU和非ICU患者分离的肺炎克雷伯菌的耐药性、以及产超广谱β-内酰胺酶(ESBL)和碳青霉烯酶的情况。方法收集2016年1-12月医院ICU和非ICU患者感染的肺炎克雷伯菌50株,其中来自ICU患者20株,非ICU患者30株,经VITEK-2Compact全自动微生物鉴定仪进行鉴定;应用K-B纸片扩散法对抗菌药物进行敏感性测定;表型确证试验筛选ESBL;改良Hodge试验(MHT)检测碳青霉烯酶活性;聚合酶链反应(PCR)实验进一步确证KPC型碳青霉烯酶。结果 ICU患者和非ICU患者分离的肺炎克雷伯菌对三代头孢菌素耐药率均在90.00%以上,对亚胺培南和美罗培南耐药的肺炎克雷伯菌仅来自于ICU患者;分离菌株中共有39株为ESBL表型确证实验阳性,其中来自ICU患者的有15株(75.00%),来自非ICU患者的有24株(80.00%),两组肺炎克雷伯菌在产ESBL方面差异无统计学意义,分离菌株中共有6株为MHT试验阳性,均来自ICU患者,其中有一株同时产ESBL和碳青霉烯酶,ICU患者和非ICU患者中分离的肺炎克雷伯菌在产碳青霉烯酶方面差异有统计学意义(P<0.05),6株MHT试验阳性菌株中,仅有3株为KPC型碳青霉烯酶,检出率为50.00%。结论 ICU患者分离的肺炎克雷伯菌对头孢吡肟、亚胺培南、美罗培南、庆大霉素和环丙沙星的耐药率要高于非ICU患者,ESBL依然是临床分离肺炎克雷伯菌产生高耐药率的主要原因之一,耐碳青霉烯类抗菌药物肺炎克雷伯菌仅出现于ICU患者,KPC型碳青霉烯酶是原因之一。

OBJECTIVE To observe and compare the drug resistance rates,extended-spectrumβ-lactamses（ESBLs）and carbapenemases in Klebsiella pneumoniae strains isolated from the ICU patients and non-ICU patients.METHODS Totally 50 strains of K.pneumoniae were isolated from the ICU and non-ICU patients with infections from Jan 2016 to Dec 2016,including 20 strains isolated from the ICU patients and 30 strains isolated from the non-ICU patients.The strains were identified by using VITEK-2 Compact automatic microorganism identification system,the drug susceptibility testing was performed with the use of K-B disk diffusion method,the ESBLs were screened by means of phenotypic confirmatory test,the carbapenemases activities were detected through modified Hodge test（MHT）,and the KPC-type carbapenemase was further confirmed by means of polymerase-chain-reaction（PCR）.RESULTS The drug resistance rates of the K.pneumoniae strains isolated from the ICU and non-ICU patients to the third generation cephalosporins were more than 90.00%,and the K.pneumoniae strains that were resistant to imipenem and meropenem were only isolated from the ICU patients.Among the isolated strains,39 isolates were positive for phenotypic confirmatory test of ESBL,15（75.00%）of which were isolated from the ICU patients,and 24（80.00%）were isolated from the non-ICU patients,and there was no significant difference in the production of ESBL between the two groups of K.pneumoniae strains.Among the isolated strains,6 isolates showed positive for MHT,all of which were isolated from the ICU patients,1 isolate produced both ESBL and carbapenemases,and there was significant difference in the production of carbapenemases between the K.pneumoniae strains isolated from the ICU patients and the strains isolated from the non-ICU patients（P〈0.05）.Of the 6 MHT-positive strains,3 were the KPC-type carbapenemase-producing strains,with the detection rate 50.00%.CONCLUSION The drug resistance rates of the K.pneumoniae strains isolated from the ICU patients are higher than those of the K.pneumoniae strains isolated from the non-ICU patients to cefepime,imipenem,meropenem,gentamicin and ciprofloxacin.ESBLs remain one of the leading causes of high drug resistance rates of the clinical K.pneumoniae isolates.The carbapenems-resistant K.pneumoniae strains are only isolated from the ICU patients,and the KPC-type carbapenemase is one of the causes.