Mcr-1阳性碳青霉烯耐药肺炎克雷伯菌耐消毒剂基因检测

Detection of disinfectant resistance genes of mcr-1 positive carbapenem resistant Klebsiella pneumoniae

目的了解mcr-1基因阳性的碳青霉烯耐药肺炎克雷伯杆菌(carbapenemase resistant K.pneumoniae,CRKP)耐消毒剂基因存在情况及其抗性检测,为临床选择合适的消毒剂提供实验室依据。方法收集2017年6月1日-2018年6月30日医院住院患者首次分离的CRKP,使用MALDI-TOF MS对细菌进行鉴定,VITEK-2Compact全自动细菌药敏分析仪对菌株进行药物敏感试验,PCR法检测多黏菌素耐药基因mcr-1及4种耐消毒剂基因:qacA/B、qacE△1-sul1(季胺类化合物)、merA(汞还原酶),tehA(亚碲酸盐抵抗蛋白质)。结果共收集到2株携带mcr-1基因的CRKP,药物敏感试验显示对多黏菌素、内酰胺类、喹诺酮类等抗菌药物均耐药,仅对复方新诺明敏感;2株细菌均检测出携带qacE△1-sul1和merA基因,而未检测出qacA/B和tehA基因,并且2株菌株对氯己定、汞溴红、84消毒液均具有抗性。结论携带mcr-1基因的CRKP对临床常用抗菌药物耐药,同时携带耐消毒剂基因并对相应消毒剂具有抗性,临床应选择合适的消毒剂来对相关的医疗器械和医院环境进行消毒,来控制这类细菌在医院的传播流行。

OBJECTIVE To investigate the presence of disinfectant resistance genes in carbapenem-resistant Klebsiella pneumoniae (CRKP) positive for mcr-1 gene and its resistance detection, so as to provide laboratory basis for clinical selection of suitable disinfectant. METHODS The CRKP strains were collected from hospitalized patients in a hospital from Jun. 1, 2017 to Jun. 30, 2018, and identified by MALDI-TOF MS. Antimicrobial susceptibility testing was performed by VITEK2 Compact. Mcr-1 gene and four disinfectant resistance genes(qacA/B , qacE △1-sul1, merA , tehA) were detected by PCR. RESULTS Two CRKP strains carrying the mcr-1 gene were isolated. Antimicrobial susceptibility testing showed that the two strains were resistant to polymyxin, lactam and quinolones and were only sensitive to sulfamethoxazole. Both strains carried qacE and merA genes, whereas qacA/B △1-sul1 and tehA genes were not detected. Meanwhile, these two strains were resistant to chlorhexidine, mercury bromine, and the 84 disinfectant. CONCLUSION Two CRKP strains carrying mcr-1 gene are resistant to common antibiotics used in clinic. In addition, the experimental strains carry disinfectant resistance genes and are resistant to the corresponding disinfectants. Consequently, appropriate disinfectants should be selected to disinfect related medical devices and hospital environments so as to control the spread of such bacteria in hospitals.