儿童肺炎患者碳青霉烯耐药肠杆菌的临床特征分析

目的：探讨儿童肺炎碳青霉烯耐药肠杆菌耐药机制和临床传播特征，分析医院感染防控措施及经验。方法：收集江苏省徐州市中心医院2017年8月至2019年10月收治的216例儿童肺炎患者中分离的46株非重复碳青霉烯耐药肠杆菌科细菌，并进行菌株鉴定、药敏试验、基因检测、同源性、传播特征及相关临床资料分析，根据脉冲场凝胶电泳（PFGE）分型将肺炎克雷伯菌携带blaNDM-1基因的儿童肺炎患者分为A型组和非A型组，并对相关数据进行统计学分析。结果：儿童肺炎患者碳青霉烯耐药肠杆菌主要包括肺炎克雷伯菌25株（54.35%）、大肠埃希菌7株（15.22%）、阴沟肠杆菌4株（8.70%）、产酸克雷伯菌4株（8.70%）、弗劳地枸橼酸杆菌3株（6.52%）及粘质沙雷菌3株（6.52%）。碳青霉烯耐药肠杆菌对阿米卡星敏感率为86.10%，对头孢唑林、头孢他啶、头孢曲松、厄他培南、美罗培南、亚胺培南和头孢哌酮/舒巴坦耐药率分别为100.00%、100.00%、100.00%、100.00%、97.70%、95.30%及95.30%。碳青霉烯耐药肠杆菌经改良Hodge试验和乙二胺四乙酸（EDTA）协同试验阳性率分别为58.70%及36.97%，聚合酶链式反应（PCR）检测携带blaKPC-2基因者27株（58.70%），携带blaNDM-1基因者16株（34.78%），携带blaIMP-4基因者1株（2.17%）。13株携带碳青霉烯耐药blaNDM-1基因的肺炎克雷伯菌PFGE分型为A型7株，B型2株，C、D、E、F型各1株。A型组和非A型组患儿重症监护室（ICU）住院史和住院时间≥30 d比较差异有统计意义（P<0.05）。结论：儿童肺炎患者碳青霉烯耐药肠杆菌呈多重耐药，耐药机制主要缘于碳青霉烯酶基因克隆传播，且与患儿ICU住院史和住院时间延长有关，临床应加强医院感染防控措施以预防耐药菌传播。

Clinical Characteristics of Carbapenem-Resistant Enterobacteriaceae in Children with Pneumonia

Objective: To probe into the drug resistance mechanism and clinical transmission characteristics of carbapenem-resistant Enterobacteriaceae in children with pneumonia, and to analyze the prevention and control measures and experience of nosocomial infection. Methods: Totally 46 strains of non-repetitive carbapenem-resistant Enterobacteriaceae isolated from 216 children with pneumonia admitted into Jiangsu Xuzhou Central Hospital from Aug. 2017 to Oct. 2019 were collected for strain identification, drug sensitivity test, genetic testing, homology, transmission characteristics and analysis of relevant clinical data. Children with Klebsiella pneumoniae carrying blaNDM-1 gene were divided into type A group and non-type A group according to pulsed field gel electrophoresis (PFGE) typing, and the relevant data were statistically analyzed. Results: Carbapenem-resistant Enterobacteriaceae in children with pneumonia mainly included 25 strains (54.35%) of K. pneumoniae, 7 strains (15.22%) of Escherichia coli, 4 strains (8.70%) of Enterobacter cloacae, 4 strains (8.70%) of Klebsiella acidophilus, 3 strains (6.52%) of Citrobacter flaudi and 3 strains (6.52%) of Serratia marcescens. The sensitivity rate of carbapenem-resistant Enterobacteriaceae to amikacin was 86.10%, and the sensitivity rates to cefazolin, ceftazidime, ceftriaxone, ertapenem, meropenem, imipenem and sulbactam/cefoperazone were respectively 100.00%, 100.00%, 100.00%, 97.70%, 95.30% and 95.30%. The positive rates of modified Hodge test and ethylenediamine tetraacetic acid (EDTA) test were respectively 58.70% and 36.97%. A total of 27 strains carrying blaKPC-2 gene, 16 strains carrying blaNDM-1 gene and 1 strain carrying blaIMP-4 gene were detected by polymerase chain reaction (PCR). Thirteen strains of K. pneumoniae carrying carbapenem-resistant blaNDM-1 gene were classified into 7 strains of type A, 2 strains of type B, 1 strain of type C, D, E and F by PFGE. There were statistically significant differences in hospitalization history in intensive care unit (ICU) and length of stay more than or equal to 30 d between type A group and non-type A group (P<0.05). Conclusion: Carbapenem-resistant Enterobacteriaceae shows multiple drug resistance in children with pneumonia. The resistance mechanism is mainly due to the cloning and transmission of carbapenem gene, which is related to the hospitalization history in ICU and prolonged length of stay of children. Therefore, the prevention and control measures of nosocomial infection should be strengthened to prevent the transmission of resistant bacteria.