结核分枝杆菌异烟肼耐药性的噬菌体测定技术研究

Comparison of four kinds of method in detection isoniazid resistance in clinical isolates of mycobacterium tuberculosis

目的建立噬菌体生物扩增法快速测定异烟肼(INH)耐药性的方法,并探讨其在结核分枝杆菌(MTB)INH耐药性测定中的应用价值。方法用PhaB法检测167株MTB临床分离株INH耐药性,并与Bactec-960测定结果比较,分析PhaB法的敏感性、特异性和准确性。结果0.2μg/ml INH与菌液37℃作用48h后,通过噬菌体检测,以噬菌斑减少95%为最适判断标准,噬菌斑减少高于95%的判为敏感株,噬菌斑减少低于95%的为耐药株。以Bactec-960测定结果为判断标准,则PhaB的敏感性、特异性、阳性和阴性预测值及符合率分别为96.4%、96.4%、93.1%、98.2%和96.4%。结论PhaB检测INH耐药性具有很高的敏感性和特异性,与Bactec-960的符合率达96.4%,只需3d时间,且操作简便、不需特殊仪器设备,可作为MTB的INH耐药性快速筛选方法。

Objective To establish Phage Amplified Biologically Assay （PhaB） detecting isoniazid（INH） resistance rapidly and evaluate PhaB assay for drug susceptibility＂ testing of isoniazid（INH） in clinical isolates of Mycobacterium tuberculosis（MTB）. Methods Detecting the INH resistance of 167 clinical isolates of MTB by＂ PhaB assay,comparing the results of PhaB with that of Bactec-960 system and analyzing the sensitivity, specificity and accuracy of PhaB assay. Results When the mixture of 0.2 μg/ml INH and MTB was incubated in 37℃ for 48 h, the accurate results were obtained rapidly by calculate the reduce of plaque of PhaB assay. If the results of Batec-960 system is the golden standard, the sensitivity, specificity, PPV. NPV and accuracy of PhaB assay was 96. 4%, 96.4%, 93.1 %, 98.2 % and 96.4 % respectively. Conclusions The PhaB assay with highly sensitivity specificity are highly consistent with Bactec 960 system. Not only it takes only three days to detect drug susceptibility of INH in clinical isolates of MTB but also it is easily to operate. We believe that this low-cost assay may be a good rapid screening of INH resistance in MTB isolates.