1株VanA型VRE菌株的鉴定及耐药诱导特性研究  

Vancomycin resistance of clinical Enterococcus isolates V309 with vanA phenotype: identification and analysis

作　　者：王雪松[1] 宋振耀[2] 邹大阳[1] 刘威[1] 魏晓[1] 黄留玉[1] 袁静[1] 

机构地区：[1]军事医学科学院疾病预防控制所,北京100071 [2]空军后勤部卫生部防疫队,北京100076

出　　处：《军事医学》2013年第12期881-886,共6页Military Medical Sciences

基　　金：国家自然科学基金资助项目(81201320)

摘　　要：目的对临床分离的耐万古霉素粪肠球菌(vancomycin-resistant Enterococcus,VRE)V309株进行鉴定及耐药特性的研究。方法用API 20 Strep生化鉴定系统和16S rDNA序列鉴定菌株,Kirby-Bauer纸片琼脂扩散法和常量肉汤稀释法测定菌株对11种抗生素的耐药谱及对万古霉素MIC值,用PCR方法鉴定菌种类型并对耐药基因型及Tn1546转座子进行检测,利用蛋白质双向电泳技术检测不同抗生素压力条件下菌体耐药蛋白的表达,并通过RT-PCR进行验证。结果 V309株为VanA型粪肠球菌菌株,对抗生素呈多药耐药性,对万古霉素MIC值≥1024μg/ml,在菌体中存在Tn1546转座子,但在无万古霉素诱导时也存在万古霉素耐药蛋白的表达。结论 VanA型粪肠球菌V309菌株对万古霉素呈高耐药性,其耐药性由Tn1546转座子介导,在该菌株中可能存在新的耐万古霉素基因诱导表达机制。Objective To identify and investigate the molecular mechanism of vancomycin resistance of Enterococcus V309 with vanA phenotype isolated clinically. Methods V309 strain was identified by API 20 Strep biochemical tests and compared with 16S rDNA gene sequences in the GenBank. Antimicrobial susceptibility of 11 types of antibacterial drugs was tested by means of Kirby-Bauer （K-B）, while the minimal inhibitory concentration（MIC） of vancomycin was detected with double agar dilution assay. Transposon Tn1546 and vancomycin resistance genes were detected by PCR. The proteome of vancomycin resistant Eraerococcusfaecalis was compared under normal and drug induced conditions using two dimensional electrophoresis （2-DE） technology and verified by semi-quantitative RT-PCR. Results V309 strain was vanA-type E.faecalis that showed multiple resistance. The MIC of vancomycin was ≥1024 μg/ml. Transposon Tn1546 was detected in V309 strain, and the expression of vancomycin-resistant proteins was observed in V309 without vancomycin induced. Conclusion The vanA-type of V309 is strongly vancomycin-resistant and is mediated by Tn1546. There may be some un- known mechanism of vancomycin resistance in V309 strain.

关 键 词：耐万古霉素肠球菌 粪肠球菌 Tn1546转座子 vanA基因 VanRS双组分系统 

分 类 号：R446.5[医药卫生—诊断学]