摘要
目的 研究产超广谱 β内酰胺酶 (ESBLs)临床分离株可转移多重耐药性的分子机制。方法 采用E 试验条进行药敏检测 ,电转化试验筛选、分离耐药质粒 ,聚合酶链反应 (PCR)扩增Ⅰ型整合子基因盒插入序列及其分子克隆和序列分析。结果 9个产ESBLs耐药质粒中有 8个检测出了插入序列 ,其中 7个携带了 1～ 2种抗药性基因盒。包括氨基糖苷类钝化酶aacA4、aadA2和aadA5 ;甲氧苄啶钝化酶dhfrA12和dfrA17;利福平钝化酶arr 3;氯霉素外排蛋白cmlA6。基因盒功能与转化子耐药表型一致。结论 质粒定位和整合子介导的抗药性基因盒可能是导致ESBLs产酶株多重耐药性产生和 (或 )播散的重要原因。
Objective To investigate the molecular mechanism of transferable multiple-antibiotic resistance in extended-spectrum beta-lactamases(ESBLs) producing isolates. Methods Antibiotics susceptibility was tested by E-test method, and multi-resistance plasmids were screened and isolated by extracting transformant plasmids. Inserted gene Cassettes of class 1 integron were amplified and analyzed by polymerase chain reaction(PCR) and DNA sequencing. Results Eight of the nine ESBL-producing plasmids were found to comprise class 1 integron sequence, of them 7 harbored 1 or 2 antibiotic resistant gene cassettes which encoding resistance to aminoglycosides (aacA4,aadA2 or aadA5),trimethoprim(dhfrA12 or dfrA17),rifampicin(arr-3) and chloramphenicol(cmlA6). The function of these gene cassettes corresponded to the resistance profiles of their electro-transformants. Conclusion Multi-resistance gene cassettes located on plasmids and mediated by class 1 integron may play an important role in causing the development and dissemination of multiple-antibiotic resistance in ESBL-producing clinical isolates .
出处
《中华结核和呼吸杂志》
CAS
CSCD
北大核心
2003年第4期199-202,共4页
Chinese Journal of Tuberculosis and Respiratory Diseases
基金
广东省科委重点攻关基金资助项目 ( 199810 )
