摘要
目的了解临床分离碳青霉烯类不敏感革兰阴性杆菌中bla_(NDM-1)基因的分布,探讨NDM-1阳性菌株的分子流行病学特征。方法收集长沙地区2011年1月—2012年8月临床分离非重复碳青霉烯类不敏感革兰阴性杆菌,聚合酶链反应(PCR)技术筛查bla_(NDM-1)基因,扩增产物测序和BLAST软件分析。对bla_(NDM-1)基因阳性菌株,采用E试验法检测其药物敏感性、PCR法检测β内酰胺酶基因(包括bla_(DHA)、bla_(VIM)、bla_(IMP)、bla_(GIM)、bla_(CTX-M)、bla_(KPC)、bla_(TEM)和bla_(SHV)等)和16S r RNA甲基化酶基因、脉冲场凝胶电泳(PFGE)及多位点序列分型(MLST)技术进行分子生物学分型。结果共收集到687株碳青霉烯类不敏感的革兰阴性杆菌,其中3株被证实为bla_(NDM-1)基因阳性菌株,包括2株肺炎克雷伯菌(菌株编号CS11495和CS610)和1株阴沟肠杆菌(菌株编号CS30754)。该3株菌均来源于湘雅医院。在测试的12种抗菌药物中,除对阿米卡星和多黏菌素B敏感外,对其余抗菌药物几乎全耐药。菌株CS11495同时检出bla_(SHV-12)、bla_(TEM-1)、bla_(CTX-M-15)和bla_(IMP-4),菌株CS610携带bla_(DHA)、bla_(SHV-12)和bla_(TEM-1),菌株CS30754中bla_(SHV-12)和bla_(TEM-1)基因阳性。其余基因均为阴性。2株肺炎克雷伯菌PFGE分型可分为A、B两型。MLST显示,菌株CS11495、CS610和CS30754分别属于ST629、ST490及ST214,其中ST490为国内首次报道。结论 bla_(NDM-1)阳性菌株具有广泛的耐药谱,与其同时携带多种耐药基因有关。尽管本地区不存在克隆传播,但分布于同一医院的不同科室,应预防其播散。
Objective To investigate the molecular characterization and prevalence of blaNDu.1 positive isolates in carbapenem non-susceptible gram-negative bacilli. Methods Carbapenem non-susceptible gram-negative isolates were collected from January 2011 to August 2012 in Changsha area. The blaNDM-1 gene was detected by PCR method. The positive products were sequenced and analyzed with BLAST. Then, antimicrobial susceptibility of blaNDM-1 positive isolates were determined by E-test. Other β-1actamase genes and 16S rRNA methylase genes were identified by PCR method, including blaDHA , bla VIM, bla IMP , bla GIM , bla CTX-M, bla KPC , bla TEM and blasHv. Finally, those bla NDM-I positive isolates were typed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Results A total of 687 carbapenem non-susceptible gram-negative isolates were collected. Three isolates were confirmed as bla NDM-1 positive isolates, including two K. pneumoniae isolates and one E. cloacae. All the three strains were derived from Xiangya Hospital. To the 12 antibiotics tested, those bla NDM-1 positive isolates were susceptible to only amikacin and polymyxin B. One K. pneumoniae strain CS 11495 was found carrying bla SHV-12, bla TEM-1, bla CTX -M-15 and bla IMP-4, while the other strains harbored bla DHA, bla SHV-12 and bla TEM-1. E. cloacae strain CS30754 was positive for bla SHV-12 and bla TEM-1. The two K. pneumoniae isolates were grouped into two types (type A and B) by PFGE. MLST results showed that CS 11495,CS610 and CS30754 strains belonged to ST629, ST490 and ST214, respectively. ST490 was reported for the first time in China. Conclusions The pan-drug resistance of bla NDM-1 positive strains may be associated with the co-existence of multiple resistance genes. The bla NDM-1 positive strain was identified in different departments of this hospital, although no clonal spread was found. Therefore, care should be taken to prevent the outbreak of this pathogen.
出处
《中国感染与化疗杂志》
CAS
CSCD
北大核心
2016年第5期631-636,共6页
Chinese Journal of Infection and Chemotherapy
基金
湖南省发改委(湘发改高技[2012]1493号
湘发改投资[2014]658号)
湖南省自然科学基金(14JJ7003)