耐碳青霉烯类肠杆菌目细菌耐药性、临床感染特征及mcr基因分析

Antimicrobial resistance,clinical infection characteristics and mcr genes of carbapenem-resistant Enterobacterales

目的分析耐碳青霉烯类肠杆菌目细菌(CRE)临床感染特征及耐药机制,为临床防治CRE感染提供参考。方法收集2021年7月—2022年6月某三甲医院临床分离的CRE菌株及患者资料,采用聚合酶链反应(PCR)检测菌株耐药基因,诱导试验验证mcr-9阳性菌株的诱导耐药性。结果共纳入167株CRE,以肺炎克雷伯菌(38.9%)和阴沟肠杆菌(35.3%)为主,呈现多重耐药表型,3株(1.8%)对多粘菌素B耐药。CRE以携带bla NDM(52.1%,87株)为主,其次为bla KPC(34.7%,58株)。根据碳青霉烯酶将CRE感染患者分为NDM组和KPC组。单因素分析结果显示,在入住ICU日数≥7 d、行气管插管、感染前使用碳青霉烯类药物等影响因素方面,KPC组高于NDM组,治愈率低于NDM组(均P<0.05)。多因素logistic回归分析结果显示,置入胃管、肺部疾病及恶性肿瘤为影响携带不同碳青霉烯酶基因CRE感染患者预后的独立危险因素(P<0.05)。多粘菌素B耐药菌株均为mgr B点突变,7株(4.2%)CRE携带mcr-9,且多数同时携带bla NDM。经多粘菌素B诱导后,4株mcr-9阳性CRE的MIC值较诱导前升高。结论该地区CRE以携带bla NDM、bla KPC为主,少数同时携带mcr-9和bla NDM,呈现多重耐药。临床应加强防控,预防其临床传播。

Objective To analyze the clinical infection characteristics and resistance mechanisms of carbapenem-resistant Enterobacterales(CRE),provide reference for clinical prevention and treatment of CRE infection.Methods Clinically isolated CRE strains and patients information in a tertiary first-class hospital from July 2021 to June 2022 were collected.Antimicrobial resistance genes were detected by polymerase chain reaction.Induced antimicrobial resistance of mcr-9 positive strains was detected by inducing test.Results A total of 167 CRE strains were collected,mainly Klebsiella pneumoniae(38.9%)and Enterobacter cloacae(35.3%).CRE strains demonstrated multiple drug resistance phenotype,with 3 strains(1.8%)exhibiting polymyxin B resistance.Most CRE strains harboured bla NDM(52.1%,n=87)and bla KPC(34.7%,n=58).Patients with CRE infection were divided into NDM group and KPC group according to carbapenemase.Univariate analysis showed that in terms of influencing factors as stay in ICU≥7 days,endotracheal intubation,and use of carbapenems before infection,KPC group was higher than NDM group,however,curing rate was lower than NDM group(P<0.05).Multivariate logistic regression analysis showed that gastric intubation,pulmonary diseases and malignant tumor were independent influencing factors for the prognosis of patients with CRE infection of different carbapenemase genes(P<0.05).Polymyxin B resistant strains all carried mgr B point mutation.7(4.2%)CRE strains harboured mcr-9,most of which also harboured bla NDM.MIC values of 4 mcr-9 positive CRE strains after polymyxin B induction were higher than those before induction.Conclusion CRE in this area mainly harbour bla NDM and bla KPC,and a few also harbour mcr-9 and bla NDM,showing multiple drug resistance.Clinical prevention and control should be strengthened to prevent its clinical transmission.