111例无菌体液标本中CRE的碳青霉烯酶检测及同源性分析

Carbapenemase detection and homology analysis of CRE in 111 sterile body fluid samples

目的了解贵州省人民医院2019年6月至2021年6月无菌体液标本中耐碳青霉烯类肠杆菌科细菌(CRE)携带碳青霉烯酶情况及同源性,为该院院感防控及临床合理用药提供参考依据。方法收集该院2019年6月至2021年6月门诊及住院患者无菌体液标本中分离到的CRE,采用BD phoenix-100或VITEK-2全自动细菌鉴定药敏仪进行细菌鉴定及药敏试验,K-B法或E-test法进行药敏结果复核。采用碳青霉烯抑制剂增强试验检测CRE产碳青霉烯酶表型,采用胶体金免疫层析法检测CRE携带的碳青霉烯酶类型,脉冲场凝胶电泳(PFGE)对肺炎克雷伯菌进行同源性分析。结果在无菌体液标本中收集的CRE菌株共111株;CRE检出率处于前3位的分别是肺炎克雷伯菌[82.0%(91/111)]、大肠埃希菌[10.8%(12/111)]、产酸克雷伯菌[3.6%(4/111)];CRE来源的无菌体液标本类型以血液标本[55.9%(62/111)]为主,其次为腹水[25.2%(28/111)]、胸腔积液[8.1%(9/111)];CRE检出率处于前3位的科室分别为肝胆外科[40.5%(45/111)]、重症监护病房[21.6%(24/111)]、血液内科[9.0%(10/111)]。碳青霉烯抑制剂增强试验检测碳青霉烯酶表型,结果显示,94株(84.7%)CRE携带丝氨酸酶,14株(12.6%)携带金属酶,同时产丝氨酸酶和金属酶的有2株,既不产丝氨酸酶也不产金属酶有1株;胶体金免疫层析法检测结果显示,108株(97.0%)携带碳青霉烯酶,其中94株(84.7%)携带KPC,13株(11.7%)携带NDM,1株携带IMP酶,1株同时携带IMP和NDM,未检测出OXA-48、VIM型碳青霉烯酶,肺炎克雷伯菌主要携带KPC(96.7%),大肠埃希菌主要携带NDM(83.4%)。PFGE检测肺炎克雷伯菌同源性,结果显示,91株肺炎克雷伯菌可分为A~O 15个型,其中A型菌株最多,B型次之。结论该院感染的CRE以肺炎克雷伯菌为主,主要携带KPC。CRE对临床常用抗菌药物普遍有较高的耐药率,肺炎克雷伯菌的同源性较高,医院应该加强院感防控,预防及减少CRE的产生。

Objective To understand the carbapenemase carrying condition and homology of carbapenem-resistant Enterobacteriaceae(CRE)in sterile body fluid samples of the hospital from June 2019 to June 2021,and to provide reference for the prevention and control of nosocomial infection and clinical rational drug use in the hospital.Methods CRE was isolated and collected from sterile body fluids samples of outpatient and inpatient patients in the hospital from June 2019 to June 2021.Bacterial identification and drug sensitivity tests were performed by BD Phoenix-100 or VITEK-2 automatic bacterial identification instrument with drug sensitivity results reviewed by K-B method or E-test method.Carbapenemase-producing phenotypes of CRE were detected by carbapenemase inhibitor enhancement assay,carbapenemase types carried by CRE were detected by gold immunochromatography,and the homology of Klebsiella pneumoniae was analyzed through pulsed field gel electrophoresis(PFGE).Results A total of 111 CRE bacterial strains was collected from sterile fluid samples from June 2019 to June 2021.The top three were Klebsiella pneumoniae[82.0%(91/111)],Escherichia coli[10.8%(12/111)]and Acid-producing Klebsiella[3.6%(4/111)].The main types of sterile body fluid samples containing CRE were blood[55.9%(62/111)],ascites[25.2%(28/111)]and pleural fluid[8.1%(9/111)].The top three departments detecting CRE were hepatobiliary surgery[40.5%(45/111)],ICU[21.6%(24/111)]and hematology[9.0%(10/111)].Carbapenemase inhibitor enhancement test was used to detect the carbapenemase phenotype.The results showed that 94 CRE strains(84.7%)carried serine enzyme,14 strains(12.6%)carried metalloenzyme,2 strains produced both serine enzyme and metalloenzyme,and 1 strain produced neither serine enzyme nor metalloenzyme.The 111 CRE strains were detected whether to carry carbapenemase by gold immunochromatography with the results that 108 strains(97.0%)carried carbapenemase.Among them,94 strains(84.7%)carried KPC carbapenase,13 strains(11.7%)carried NDM carbapenemase,1 strain carried IMP carbapenase and 1 strain carried both IMP and NDM carbapenemase.But the OXA-48 and VIM carbapenase were not detected.Klebsiella pneumoniae mainly carried KPC carbapenase(96.7%),while Escherichia coli mainly carried NDM carbapenase(83.4%).PFGE was applied to detect the homology of Klebsiella pneumoniae,and the results showed that 91 strains of Klebsiella pneumoniae could be divided into 15 types from A to O.Among them,type A strains were the most,followed by type B.Conclusion Klebsiella pneumoniae is the main infection of CRE in the hospital,among which Klebsiella pneumoniae mainly carries KPC carbapenemase.CRE generally has a high drug resistance rate to commonly used clinical antibiotics,and the homology of Klebsiella pneumoniae is higher.Therefore,hospitals should strengthen the prevention and control of hospital infection to prevent and reduce the occurrence of CRE.