微孔板变色硅胶显色法检测结核分枝杆菌耐药性

Testing of drug resistance of Mycobacterium tuberculosis by microplate allochroic silica gel assay

目的用微孔板变色硅胶显色法检测结核分枝杆菌(MTB)对异烟肼(INH)、利福平(RFP)、乙胺丁醇(EMB)、链霉素(SM)4种一线抗结核药物的耐药性,并分析该方法的临床应用价值。方法对本院2014年1月至2016年12月结核病实验室保存的150株MTB临床分离株用微孔板变色硅胶显色法分别检测4种抗结核药物的耐药性,并与BACTEC MGIT960检测法作比较。结果微孔板变色硅胶显色法最佳接种菌量为10^(-3) mg/ml,检测最佳时间为7~10 d,INH、RFP、EMB、SM 4种药物的最佳MIC判断界值分别为0.25、1、4、2μg/ml。以Bactec MGIT960药敏结果为标准,微孔板变色硅胶显色法检测四种一线抗结核药物符合率同Bactec MGIT960高度一致,差异无统计学意义(INH:χ~2=1.23,P>0.05;RFP:χ~2=1.21,P>0.05;EMB:χ~2=1.45,P>0.05;SM:χ~2=1.25,P>0.05),其准确度分别达96.7%、98.0%、92.0%、96.0%。结论微孔板变色硅胶显色法检测MTB的耐药性具有成本低、快捷、操作简便、便于观察判断等优点,为MTB耐药检测提供了一种较好的方法,适合推广使用。

Objective To test the resistance of Mycobacterium tuberculosis to isoniazid（INH）, rifampicin（RFP）, ethambutol（EMB,） and streptomycin（SM） by using microplate allochroic silica gel assay to assess its clinical application value. Methods One hundred and fifty clinical isolates of Mycobacterium tuberculosis from Nantong Sixth People′s Hospital were applied to test their resistance to the four kinds of first-line antituberculous drugs by microplate allochroic silica gel assay, and the results were compared with those obtained by the Bactec MGIT method. Results The best concentration of MTB in microwell is 10^（-3） mg/ml. The time of detection for microplate allochroic silica gel assay was 7-10 days. The best thresholds for detecting drug susceptibility of INH, RFP, EMB, and SM were 0.25 μg/ml, 1 μg/ml, 4 μg/ml, and 2 μg/ml, respectively. According to the results of Bactec MGIT method, the accuracies of the microplate allochroic silica gel assay were 96.7%, 98.0%, 92.0%, and 96.0%, respectively. Conclusion The microplate allochroic silica gel assay for detecting drug resistance of Mycobacterium tuberculosis is accurate, rapid, inexpensive, and simple, and can meet the need of rapid clinical diagnosis.