莫西沙星抗结核分枝杆菌浓度标准的研究

Study on definition of critical concentration of moxifloxacin against Mycobacterium tuberculosis

目的通过比较新患者与复治患者分离结核分枝杆菌的莫西沙星最低抑菌浓度(MIC)的差异,确定莫西沙星的临床耐药界限。方法根据患者治疗史,选取109例肺结核病新患者分离出的菌株以及使用过莫西沙星治疗复治患者31例分离出的菌株,共140株,以罗氏含药培养基测定MIC,并分析MIC分布状况,比较MIC累计百分比,通过新患者菌株和复治患者菌株差值最大时的MIC作为耐药界限。结果来自既往未用过莫西沙星治疗新患者的临床分离株中,94.50%的菌株MIC<0.4μg/ml,既往曾接受莫西沙星治疗的临床分离株中,MIC>1.0μg/ml占93.55%。结论根据MIC分布,两类患者分离的结核分枝杆菌对莫西沙星MIC的差异,提示使用罗氏培养基的莫西沙星药敏试验耐药界限采用1μg/ml为宜,复治患者中仍有6.45%对莫西沙星敏感。

OBJECTIVE To compare the difference in the minimum inhibitory concentration （MIC） of moxifloxacin （MFX） against Mycobacteriurn tuberculosis strains isolated from the patients newly treated with MFX and the patients previously treated with MFX so as to determine the critical point of clinical resistance of MFX. METHODS According to treatment history, 140 strains from 109 new TB cases and 31 previously treated cases were selected, and MIC of them were tested with Lowenstein-Jensen medium（L-J）. Distribution of MIC was analyzed. After comparison of accumulative proportion of MIC, the critical concentration was determined. RESULTS Of the clinical isolates from the patients who never previously used MFX, 94. 50% of the isolates were with MIC less than 0.4 μg/ml against MFX; of the clinical isolates from the patients who previously used MFX, 93.55% were with the MIC more than 1.0 9g/,m against MFX. CONCLUSION According to MIC distribu~：ion and difference between two kinds cases, it is suggested that critical concentration of moxifloxacin with L-J medium for drug susceptibility test would be 1 μg/ml; among the previously treated cases there are 6. 45% cases that are susceptible to moxifloxacin.