产超广谱β-内酰胺酶菌株质粒图谱与耐药性分析

RELATIONSHIP BETWEEN PLASMID MAP AND DRUG RESISTENCE IN ESBL-PRODUCING STRAINS

目的了解临床分离产超广谱β-内酰胺酶(ESBLs)菌株的质粒分布情况,初步探讨产ESBLs菌株质粒图谱与其耐药表型的关系。方法收集临床分离的产ESBLs菌51株,应用碱裂解法提取质粒DNA,琼脂糖凝胶电泳分析质粒图谱,采用MicroScan WalkAway 96Plus微生物鉴定-药敏测试系统分析产ESBLs菌对24种常用抗生素的敏感性,参照美国临床实验室标准化研究标准进行操作及结果判断。结果 51株产ESBLs菌株中质粒的检出率为62.75%,不同菌株中质粒数目1～3条,含相同质粒条带的菌株,其质粒电泳条带分布一致;含不同质粒条带的菌株均对一代、二代、三代头孢药物耐药性最高,对氨曲南、头孢曲松、头孢他啶、氧哌嗪青霉素的耐药率也较高,对亚胺硫霉素、美罗培南、丁胺卡那霉素、哌拉西林-三唑巴坦敏感。各菌株耐药性与质粒条带数无显著相关性。结论产ESBLs菌株质粒图谱与耐药性无显著相关性。

Objective To investigate the relationship between plasmid profile and antibiotic resistance of extended-spec- trum beta-lactamase （ESBL）-producing strains isolated, from clinical specimen. Methods A total of 51 strains of ESBL-produ- cing strains were isolated. The plasmid map was detected by agarose gel electrophoresis. Plasmid DNA was extracted by ikaline lysis method. Antimicrobial susceptibility testing was analyzed by MicroScan WalkAway 96 Plus microorganism test/drug sensitivity test system, and the result was determined according to CLSI standard. Results The plasmid was detected in 62.75% of the 51 strains. The resistant strains had 1 to 3 plasmid bands. The plasrnids which had similar plasmid number had similar plasmid profile in agarose electrophoresis. All the strains were resistant to the first, the second and the third generation cephalosporins, and were also resistant to amikacin sulphate, aztreonam, rocephin, fortum and piperacillin. The strains were sensitive to imipenem, mepem, amikaein sulphate and tazocin. Statistical analysis results showed that there was no significant correlation between the strain resis- tance and plasmid banding number. Conclusion There is no significant correlation between drug resistance and the piasmid map in ESBL-producing bacteria.