耐甲氧西林金黄色葡萄球菌对万古霉素敏感性的变迁

目的　通过对近年来耐甲氧西林金黄色葡萄球菌 (MRSA)临床分离株对万古霉素抑菌圈直径的分析 ,研究MRSA对万古霉素敏感性的变化。方法　药敏试验采用纸片扩散法 (K B法 ) ,抑菌圈直径的比较采用t检验。结果　 1994～ 2 0 0 0年每年收集的临床分离的MRSA菌株数分别为 2 18、187、2 92、2 37、35 1、886和 6 5 2 ,各年菌株对万古霉素抑菌圈的平均直径 (mm)分别为 19 9、19 1、18 6、17 4、18 4、18 2和 17 8。 2 0 0 0年的 6 5 2株MRSA对万古霉素抑菌圈的平均直径 (17 8mm)明显小于1994年 2 18株MRSA的平均直径 (19 9mm) ,差异有显著性 (P <0 0 0 1)。 2 0 0 0年分离的MRSA对氯霉素、环丙沙星、红霉素、庆大霉素、四环素和复方新诺明等常用抗生素的耐药率均很高 ,其耐药百分率分别为 44 0 %、73 7%、89 1%、6 5 7%、6 1 0 %和 6 7 0 %。结论　 1994年到 2 0 0 0年MRSA对万古霉素的敏感性在逐年降低 ,加强金黄色葡萄球菌对万古霉素敏感性的监测非常必要。

The change in sensitivity of methicillin-resistant Staphylococcus aureus to vancomycin

Objective To determine the shift of susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) isolates to vancomycin in recent years. Methods Antimicrobial susceptibility was determined by disk diffusion test (K-B method). The t-test was used to compare the mean diameters of zone of inhibition. Results The clinical isolates of MRSA from 1994 to 2000 were 218, 187, 292, 237, 351, 886 and 652 in number respectively. The mean diameters(mm) of the inhibition zone of MRSA isolates each year were 19.9, 19.1, 18.6, 17.4, 18.4, 18.2 and 17.8. Comparison of the diameters of the inhibition zone of MRSA isolates (K-B method) showed that the mean diameter of the inhibition zone from the 652 MRSA isolates in 2000 was much less than that of the 218 MRSA isolates in 1994 and the difference was significant (P<0.001). The resistant rates to chloramphenicol, ciprofloxacin, erythromycin, gentamicin, tetracycline and trimethoprim/sulfamethoxazole were 44.0%, 73.7%, 89.1%, 65.7%, 61.0% and 67.0%. Conclusion Our observation demonstrated that the susceptibility of MRSA to vancomycin gradually decreased from 1994 to 2000. It is important to monitor the antimicrobial susceptibility of Staphylococcus aureus to vancomycin.