肠球菌庆大霉素高耐性传递

The Transfer of Gentamicin High Level Resistance in Enterococcus

目的 对临床分离的肠球菌进行药敏分析 ,研究其庆大霉素高耐性的遗传学基础。 方法 通过电击转化和质粒丢失试验确定庆大霉素高耐性质粒 ,PCR扩增和末端双脱氧法测序分析庆大霉素高耐基因。 结果 确定一庆大霉素高耐性质粒 (p G30 1)及其重组质粒 (p G40 1) ,PCR扩增出一 1.6 kb扩增片段 ,测序结果与 6 '- O-氨基糖苷乙酰转移酶 - 2 " - N -氨基糖苷磷酸转移酶 [aac(6 ') - aph(2 " ) ]双功能酶基因基本一致。 结论 在所分离的肠球菌中 ,耐药性相当普遍。庆大霉素高耐基因可位于不可自主接合转移的较小质粒上 ,在电击转化过程中可发生重组 ,在此质粒中介导庆大霉素高耐性的基因是 aac(6 ') - aph(2 " )

Objective To investigate the antibiotic sensibility the genetic basis of high level gentamicin resistance(HLGR) of Enterococcus. Methods Electroporation and plasmids cuting experiments were performed to identify the HLGR plasmid, polymerase chain reaction(PCR) and nucleotides sequencing used to analyze the HLGR gene. Results A HLGR plasmid and its recombinant plasmid(designated pG301(14 5 kb) and pG401(35 kb) respectively) were identified. A 1 6 kb fragment was acquired by PCR with pG301 as template. Fragment was determined to be the gene specifying 6' N aminoglycoside acetyltransferase 2' O phosphatransferase[aac(6') aph(2')] by nucleotide sequencing. Conclusion Most of the enterococcus strains isolated from clinical samples are resistant to several different antibiotics. The HLGR gene also locates in plasmid which can't transfer independently but recombine during electroporation. The HLGR gene in this plasmid is aac(6') aph(2').