微孔板稀释法检测结核分枝杆菌丙硫异烟胺耐药结果分析

摘要

We compared the MGIT 960 method,the reference,and the broth microdilution method for detecting the susceptibility of Mycobacterium tuberculosis isolates to protionamide (PTO).We performed drug susceptibility testing for 248 M.tuberculosis clinical isolates to PTO using MGIT 960 and broth microdilution method.In addition,a total of 117 isolates were randomly selected for further evaluation of the consistency of the minimal inhibitory concentrations determined by these two methods,and eleven concentrations of PTO had been involved accordingly (0.062 5,0.125,0.25,0.5,1,2,4,8,16,32,64 μg/mL).The MGIT method showed an average detection time of 10.1 days,while the detection period of broth microdilution method was 8 days,and the difference was statistically significant (P＜0.001).In addition,the rate of the sensitivity,specificity and concordance between these two methods was 96.5％ (55/57),93.2％ (178/191),and 94.0％ (233/248),respectively.The Kappa value was 0.84.Comparison of the MIC values detected by different methods revealed that the overall concordance rate was 81.2％ (95/117).For the isolates harboring low MIC values (MIC＜8.0 μg/mL),the concordance rate was 86.3％ (82/95),while that of the isolates with high MIC values was only 59.1％ (13/22).In conclusion,our data demonstrate that the broth microdilution method showed excellent concordance with MGIT method for detecting the resistance rate of M.tuberculosis isolates to PTO,indicating that the broth microdilution method with available performance,short turn-around time and convenient manual operation was suitable for rapid detection of M.tuberculosis to PTO.%目的 以MGIT960快速药敏法为参照,微孔板稀释法检测结核分枝杆菌丙硫异烟胺耐药的效果.方法 采用MGIT960快速药敏(MGIT法)和微孔板稀释法对248株结核分枝杆菌临床分离株进行丙硫异烟胺药敏试验,检测结核分枝杆菌对该药物的耐药性.随机选取117株菌株进行该药物的11个浓度梯度(0.0625、0.125、0.25、0.5、1、2、4、8、16、32、64βg/mL)的药敏检测,比较两种方法最低抑菌浓度的一致性.结果 MGIT法的平均检测时间为10.1d,微孔板稀释法检测时间为8d,两者差异有统计学意义(P＜0.001).与MGIT法测定结果比较,微孔板稀释法检测的敏感度为96.5％(55/57),特异度为93.2％(178/191),符合率为94.0％(233/248),Kappa值为0.84.两种方法所获得的MIC值的总一致率为81.2％(95/117),其中在MIC值＜8.0 μg/mL的分离株中,两种方法的一致率为86.3％(82/95);在MIC值≥8.0 μg/mL的分离株中,两种方法的一致率仅为59.1％(13/22).结论 两种方法对丙硫异烟胺进行耐药检测有较高的一致性,但也存在一定的差异.微孔板稀释法比MGIT法简单,快速,适合用于结核分枝杆菌对丙硫异烟胺耐药性的快速检测.