臭鼻克雷伯和鲍曼不动杆菌中检出NDM-1型金属β内酰胺酶基因

摘要

目的 调查对碳青霉烯类抗菌剂敏感性降低的肠杆菌和鲍曼不动杆菌中NDM-1型金属β内酰胺酶基因的存在情况.方法 应用改良Hodge试验和EDTA协同试验对2007～2010年本院收集的对碳青霉烯类抗菌剂敏感性降低的肠杆菌和鲍曼不动杆菌进行碳青霉烯酶筛选.PCR法扩增NDM-1基因,并对PCR扩增阳性产物进行DNA测序分析.对NDM-1基因阳性菌株用PCR方法检测armA和rmtB16S rRNA甲基化酶基因,VIM、SPM、IMP和KPC碳青霉烯酶基因以及Ⅰ类整合子.Etests法进行药敏试验.结果 70株肠杆菌中10株Hodge Test和EDTA协同试验阳性,55株鲍曼不动杆菌中6株EDTA协同试验阳性.其中1株臭鼻克雷伯和3株鲍曼不动杆菌PCR扩增出NDM-1型金属β内酰胺酶基因目的片段,经测序比对为NDM-1型基因.其中1株臭鼻克雷伯和1株鲍曼不动杆菌检测出armA型16S rRNA甲基化酶基因,1株鲍曼不动杆菌检测出2 000 bp左右的Ⅰ类整合子,未检出除NDM-1型外的其他碳青霉烯酶基因.NDM-1基因阳性菌除对替加环素、多黏菌素B敏感外,对其他检测的抗菌剂均耐药.结论 臭鼻克雷伯和鲍曼不动杆菌中存在NDM-1型金属β内酰胺酶基因,有的携带armA型16S rRNA甲基化酶基因和Ⅰ类整合子,为该地区首次报道.%Objective To investigate the prevalence of NDM-1 gene in multidrugresistant Enterobacteriaceae and Acinetobacter baumannii. Methods Carbapenemases were screened by Modified Hodge Test and EDTAdisk synergy test. The encoding genes of NDM-1 was amplified by PCR and DNA sequencing. Encoding genes of 16S rRNA methylase,VIM,SPM,IMP and KPC gene was amplified by PCR and DNA sequencing. Antibiotic susceptibilities were assessed by Etests. Results 10 of 70 isolates Enterobacteriaceae were positive by Hodge Test and EDTAdisk synergy test,6 of 55 isolates Acinetobacter baumannii were positive by FDTAdisk synergy test. Of these 125 Enterobacteriaceae and Acinetobacter baumannii,1 Klebsiella ozaenae and 3 Acinetobacter baumannii were NDM-1 positive by PCR and DNA sequencing. 1 Klebsiella ozaenae and l Acinetobacter baumannii were armA 16S rRNA methylase gene positive. the strain carrying NDM-1 gene was sensitive to polymyxin B and tigecycline. Conclusion Klebsiella ozaenae and Acinetobacter baumannii carry NDM-1 gene,This is the first report of NDM-1 in Guangzhou.