利福平和利福布汀对结核分枝杆菌交叉耐药率的初步探讨

Study on the Incidence of Cross Resistance between Rifampicin and Rifabutin in Mycobacterium tuberculosis Clinical Isolates

目的通过对结核分枝杆菌MIC的测定，初步探讨利福平和利福布汀两药间的交叉耐药率。方法利用Alamar Blue法（Alamar blue susceptibility test，MABA）检测116株结核分枝杆菌临床分离株对利福平和利福布汀的体外MIC。结果36株利福平敏感株均对利福布汀敏感；80株利福平耐药株中有58株对利福布汀也同时耐药（对利福布汀的MIC〉0．5／μg／ml），利福平与利福布汀间的交叉耐药率为72．5％（58/80）；同时对利福平和利福布汀耐药的菌株对两种药物的耐药程度呈现正相关。结论利福布汀较利福平有更好的体外抗菌活性。对于利福平耐药而利福布汀敏感的患者仍可选择利福布汀作为联合化疗的有效药物之一。

Objective To determine the incidence of cross resistance between rifampicin and rifabutin by testing the minimal inhibitory concentrations （MICs） of rifampicin and fifabufin against Mycobacterium tuberculosis （M. tuberculosis） clinical isolates, Methods The liquid dilution method was performed to detect MICs of rifampicin and rifabutin in 116 M. tuberculosis clinical isolates. Results Rifabutin was susceptible to all isolates which were susceptible to rifampicin. Cross resistance between rifampicin and rifabutin was 72.5%. Conclusions Rifabutin has a higher antibacterial activity in vitro compared to rifampicin. Rifabutin might be one of an active drug in combination therapy for cases with rifampicin resistant tuberculosis when the isolate is detected susceptible to fifabutin,