耐碳青霉烯革兰阴性杆菌耐药性及耐药基因blaKPC的分子特征

目的 探讨耐碳青霉烯类革兰阴性杆菌的临床耐药性及耐药基因blaKPC的分子特征。方法 分析2017年1月-2018年12月某院临床检出的耐碳青霉烯类革兰阴性杆菌。通过WHONET 5.6软件对药物敏感试验数据进行统计分析，采用PCR检测碳青霉烯耐药基因blaKPC、blaNDM、blaIMP、blaVIM、blaOXA-48，对PCR阳性产物进行DNA测序，分析耐药基因的分子结构特点。结果 共收集510株耐碳青霉烯类革兰阴性杆菌，其中耐碳青霉烯类肠杆菌科细菌（CRE）420株，耐碳青霉烯非肠杆菌科细菌90株。菌株主要来自重症监护病房（ICU）、神经外科和呼吸科，分别占60.8%、11.8%、5.3%；标本来自痰、脓性分泌物、静脉血、无菌中段尿，分别占66.9%、8.8%、8.2%、6.5%。耐碳青霉烯类革兰阴性杆菌对常用抗菌药物具有较高的耐药性。PCR结果显示，420株CRE中blaKPC、blaNDM、blaIMP的阳性率分别为54.3%（228/420）、1.2%（5/420）、1.4%（6/420），未检测出blaVIM和blaOXA-48基因，其中肺炎克雷伯菌、产气肠杆菌、大肠埃希菌分别占携带blaKPC CRE的83.8%、11.8%、2.6%；其他少见菌种中也检出blaKPC基因。非肠杆菌科细菌中仅有2株鲍曼不动杆菌检测出blaKPC。DNA测序结果显示，174株携带blaKPC的菌株中173株检测为blaKPC-2、1株检测为blaKPC-1。结论 该地区耐碳青霉烯类革兰阴性菌以CRE为主，其中以携带blaKPC-2的肺炎克雷伯菌占绝对优势，其他菌株中也均有发现。提示临床需重点加强耐碳青霉烯类肺炎克雷伯菌的监测及预防，防控blaKPC的传播流行。

Drug resistance of carbapenem-resistant Gram-negative bacilli and molecular characteristics of drug resistance gene blaKPC

Objective To investigate the clinical drug resistance of carbapenem-resistant Gram-negative bacilli and molecular characteristics of drug resistance gene blaKPC. Methods Clinically isolated carbapenem-resistant Gram-negative bacilli in a hospital from January 2017 to December 2018 were analyzed. Antimicrobial susceptibility testing data were statistically analyzed by WHONET 5.6 software, carbapenem-resistant genes blaKPC, blaNDM, blaIMP, blaVIM, and blaOXA-48 were detected by polymerase chain reaction (PCR), PCR positive products were performed DNA sequence to analyze the molecular structure of drug resistance genes. Results A total of 510 strains of carbapenem-resistant Gram-negative bacilli were collected, including 420 strains of carbapenem-resistant Enterobacteriaceae (CRE) and 90 strains of carbapenem-resistant non-Enterobacteriaceae. Strains were mainly from intensive care unit (ICU), departments of neurosurgery and respiratory, accounting for 60.8%, 11.8% and 5.3% respectively; specimens were from sputum, purulent secretion, venous blood, and sterile midstream urine, accounting for 66.9%, 8.8%, 8.2% and 6.5% respectively. Carbapenem-resistant Gram-negative bacilli were highly resistant to commonly used antimicrobial agents. PCR results showed that among 420 strains of CRE, positive rates of blaKPC, blaNDM, and blaIMP were 54.3% (228/420), 1.2% (5/420), and 1.4% (6/420) respectively. blaVIM and blaOXA-48 genes were not found, Klebsiella pneumoniae, Enterobacter aerogenes, and Escherichia coli accounted for 83.8%, 11.8%, and 2.6% of blaKPC-carrying CRE respectively; blaKPC was also detected in other rare strains. blaKPC was detected in only 2 strains of Acinetobacter baumannii in non-Enterobacteriaceae. DNA sequencing showed that among 174 strains carrying blaKPC, 173 strains were found blaKPC-2 and 1 strain was found blaKPC-1. Conclusion CRE is the main Gram-negative bacteria resistant to carbapenems in this area, dominantly Klebsiella pneumoniae carrying blaKPC-2, and other strains are also found. It is suggested that the monitoring and prevention of carbapenem-resistant Klebsiella pneumoniae should be strengthened to prevent and control the spread of blaKPC.