耐红霉素屎肠球菌耐药基因及其水平转移研究  

Analysis of high level erythromycin resistance associated genes and horizontal gene transfer of Enterococcus faecium

作　　者：王珊[1] 郑波[1] 李耘[1] 刘健[1] 薛峰[1] 吕媛[1] 

机构地区：[1]北京大学第一医院临床药理研究所,北京100034

出　　处：《中国抗生素杂志》2009年第12期739-742,共4页Chinese Journal of Antibiotics

基　　金：国家科技重大专项课题(重大新药创制;2008ZX09313-017)

摘　　要：目的研究我国临床分离高水平耐红霉素的屎肠球菌中红霉素耐药基因及其水平转移情况。方法采用PCR法检测红霉素耐药基因ermB和mef,转座子Tn917相关基因tnpA。采用质粒酶切图谱分析耐药菌同源性,采用固体培养基传递法和液体培养基传递法研究红霉素耐药基因水平转移情况。结果90株高水平红霉素耐药屎肠球菌中ermB基因阳性率为85.6%(77/90),mef基因均为阴性,15.6%(14/90)tnpA基因阳性的肠球菌中ermB基因均为阳性。质粒酶切图谱显示除来自同家医院的4株菌质粒酶切图谱相同外,其余菌株质粒酶切图谱差异明显。14.3%(11/77)菌株携带的ermB基因在屎肠球菌间可通过固体传递水平转移,2.6%(2/77)菌株携带的ermB基因在屎肠球菌间液体环境中水平转移。13株接合子经过PCR鉴定,ermB基因均为阳性,但tnpA基因皆为阴性。结论高水平耐红霉素的屎肠球菌ermB基因携带率较高,且该基因可在屎肠球菌间水平转移,可水平转移的ermB基因可能位于其它非Tn917转座子和/或接合性质粒上。14株屎肠球菌ermB基因可能存在于转座子Tn917内。这些菌株间大多没有同源性。Objective To analyse the resistance and horizontal gene transfer of high level erythromycin resistant Enterococcus faecium. Method PCR technique was applied to identify genes including ermB, reef, and tnpA. Plasmid DNA was treated with restriction enzymes and subjected to agarose gel electrophoresis for the analysis of DNA fragments. The transferability of the erythromycin resistance was examined by solid mating and broth mating. Result Of the 90 HLER E. faecium, 85.6% （77/90） were positive for ermB gene, and 15.6% （14/90） positive for both tnpA and ermB gene. All isolates were negative for reef gene. Majority of the plasmid patterng were identified in single isolates. 14.3% （11/77） isolates with ermB were horizontal transferred between E. faecium strains in solid mating. 2. 6% （2/77） isolates were horizontal transferred between E. faecium in broth mating. The 13 conjugations were positive for ermB gene, and negative for tnpA gene. Conclusion This study indicated that the positive rate of ermB gene were higher among HLER E. faecium isolates and this gene can horizontal transfer between E. faecium. The ermB gene which can horizontal transfer maybe on other transposon Tng17 and/or conjugative plasmids. The ermB gene of the 14 HLER E. faecium maybe on Tn917. There were no obvious homology in the HLER E. faecium isolates.

关 键 词：屎肠球菌 高水平红霉素耐药 TN917 基因水平转移 

分 类 号：R378[医药卫生—病原生物学]