新型肠球菌万古霉素耐药基因簇——vanM基因簇  

vanM gene cluster,a novel vancomycin resistance gene cluster found in Enterococcus faecium

作　　者：徐晓刚[1] 吴湜[1] 叶信予[1] 郭燕[1] 林东昉[1] 胡付品[1] 朱德妹[1] 王明贵[1] 

机构地区：[1]复旦大学附属华山医院抗生素研究所,上海200040

出　　处：《中国感染与化疗杂志》2009年第6期436-439,共4页Chinese Journal of Infection and Chemotherapy

基　　金：国家重点基础研究发展计划(973计划)资助项目(2005CB523101);上海市科学技术委员会资助项目(09411967900)

摘　　要：目的从屎肠球菌临床分离株中克隆一种介导屎肠球菌对万古霉素耐药的新基因簇。方法采用16S rRNA测序对临床株Efm-HS0661进行菌种确认,并行多位点序列分型(MLST);通过药敏试验及接合试验,了解菌株耐药性及其可转移性;通过PCR扩增、步移法测序、限制性内切酶片段克隆获取万古霉素耐药基因及其周边序列,并将获得序列与已知万古霉素耐药基因簇进行比对。结果临床株经16S rRNA测序确认为屎肠球菌,MLST分型属ST78型;该菌株对万古霉素及替考拉宁耐药,且可通过接合试验发生转移;测序获得一6 592bp核苷酸序列,为含6个万古霉素耐药相关基因的基因簇,其基因结构与已知耐药基因簇不同,命名为vanM型基因簇。其中vanM全长1 032bp,其编码蛋白VanM与VanA、VanB、VanD、VanF基因氨基酸序列同源性分别为79.7%、69.7%、66.0%和78.5%。结论从万古霉素耐药屎肠球菌临床株中发现了一种新型万古霉素耐药基因簇———vanM型基因簇。Objective To clone a novel vancomycin-resistant gene cluster in an clinical isolate of E. faecium. Methods 16S rRNA sequence analysis, multilocus sequence typing （MLST）, antimicrobial susceptibility testing and conjugation experiment were carried out for the clinical isolate Efm-HS0661. By PCR amplification, walking sequencing, and restriction fragment cloning, the vancomycin-resistant gene and its flanking sequences were determined. The obtained sequence was compared with known vancomycin resistance gene clusters for sequence identity. Results The clinical isolate was identified as E. faecium by 16S rRNA sequencing, with MLST type ST78. This isolate was resistant to vancomycin and teicoplanin. The resistance could be transferred by conjugation. Within a 6 592 bp nucleotide sequence obtained, a gene cluster carrying 6 genes related to vancomycin resistance was found. It is designated as vanM gene cluster. Its genetic structure is different from those known vancomycin resistance gene clusters, vanM gene is 1 032 bp in length and encoded a 343-amino-acid protein, which shared 79.7%, 69. 7%, 66.0% and 78.5% amino acid identity with VanA, VanB, VanD, and VanF, respectively. Conclusions A novel vancomycin-resistant gene cluster, vanM gene cluster, has been found in an isolate of vancomycin resistant E. faecium.

关 键 词：万古霉素 耐药 基因簇 屎肠球菌 

分 类 号：R450[医药卫生—治疗学]