IS256与医院感染表皮葡萄球菌耐氨基糖苷类抗菌药物的关系

目的了解医院感染表皮葡萄球菌对不同类型氨基糖苷类抗菌药物的敏感特征，分析插入序列（IS）256与表皮葡萄球菌耐氨基糖苷类抗菌药物的关系。方法收集2007年2月至2007年7月外科病区中引起医院感染的表皮葡萄球菌48株，利用纸片扩散法测定细菌对4种氨基糖苷类抗菌药物（庆大霉素、奈替米星、链霉素和阿米卡星）药敏特征；构建IS256特异性引物，利用聚合酶链反应（PCR）检测48株细菌中IS256分布状况。结果48株临床分离的表皮葡萄球菌对4种氨基糖苷类抗菌药物的药敏特征分别为：对庆大霉素的耐药率为69％，敏感率为31％；对奈替米星的耐药率为8％，敏感率为79％，中介率为13％；对链霉素的耐药率为42％，敏感率为35％，中介率为23％；对阿米卡星的耐药率为15％，敏感率为75％，中介率为10％。全部临床分离株中，有25株细菌检出IS256。在庆大霉素耐药菌株中，IS256检出率高达70％，与敏感菌相比差异具有统计学意义（P〈0．01）；而对其他3种抗菌药物耐药的菌株中，IS256的检出与耐药无明显相关性（P〉0．05）。结论表皮葡萄球菌临床分离株对氨基糖苷类抗菌药物存在不同程度耐药。IS256与表皮葡萄球菌对庆大霉素耐药密切相关。

Analysis of the relationship between insertion sequence 256 and aminoglycosides resistance in nosocomial in fection with Staphylococcus epidermidis

Objective To investigate the susceptibility of Staphylococcus epidermidis to different kinds of aminoglycoside and analyze the relationship between insertion sequence （IS）256 and Staphylococcus epidermidis aminoglycoside resistance. Methods A total of 48 clinical isolates from surgical department were analyzed in this study. The isolates were tested for antimicrobial susceptibility to aminoglycosides resistance, including gentamicin, netilmicin , streptomycin and amikacin, by the disc agar diffusion method; IS256 was detected by polymerase chain reaction（PCR）. Results These 48 Staphylococcus epidermidis isolates had different resistance to aminoglycosides. The resistance and susceptibility to gentamicin was 69% and 31% respectively. The resistance, susceptibility and intermediary to netilmicin was 8% , 79% and 13% ,streptomycin was 42% ,35% and 23% and amikacin was 15% ,75% and 10%. Among them, 25 strains had IS256 . The IS256 positive rate was much higher in gentamicin-resistant isolates（70% ） than in gentamicin- sensitive isolates （P 〈0.01 ）. The IS256 positive rate in netilmicin ,streptomycin and amikacin-resistant isolates had little difference with the sensitive isolates （ P 〉 0.05 ）. Conclusions The clinical Staphylococcus epidermidis isolates show high resistance to different aminoglycosides. IS256 is a very important factor which mediates the resistance to gentamycin of Staphylococcus epidermidis.