噬菌体法与BacT/ALERT3D检测吡嗪酰胺对耐药性结核分枝杆菌的比较研究

摘要

[目的]建立噬菌体生物扩增法(PhaB法)快速测定吡嗪酰胺(PZA)耐药性,探讨其在结核分枝杆菌(MTB)PZA耐药性测定中的应用价值.[方法]应用MTB噬菌体法快速MTB耐药的PhaB方法并用于测定115株MTB临床分离株耐药性.同时与BacT/ALERT 3D药敏试验结果相比较,对耐药性测定结果不符合的菌株测定其最低抑菌浓度(MIC).[结果]PhaB法检测PZA耐药性的最佳测定条件为pH值5.5、药物浓度200 mg/L、37℃作用48 h.115株临床分离株,PhaB法敏感90株,耐药25株;BacT/ALERT 3D法敏感87株,耐药28株;其中两种方法均敏感85株,均耐药24株,即测定结果相符109株,符合率94.78%;测定结果不符6株,不符合率5.22%.如以BacT/ALERT 3D测定结果为判断标准,则PhaB检测PZA耐药性的敏感性为85.71%(24/28),特异性为97.70%(85/87),阳性预测值为96%(24/25),阴性预测值为94.44%(85/90),准确性为94.78%(109/115).[结论]PhaB法检测PZA耐药性只需2~3 d时间,操作简便,不需特殊仪器设备,可作为MTB的PZA耐药性快速筛选方法.%[Objective] To set up the phage-amplified biological assay(PhaB) for the rapid detection of pyrazinamide (PZA) resistance and to explore the value of PhaB in the detection of PZA resistance in Mycobacterium tuberculosis (MTB). [Methods] The drug resistance of 115 clinical isolates of MTB was detected by PhaB. The drug sensitivity re sult between PhaB and BacT/ALERT 3D was compared. The minimal inhibitory concentration(MIC) of the strains with discrepant results of the resistance was measured. [Results] The optimal detection condition of PhaB for PZA resistance was that pH was 5.5, and the concentration of PZA was 200μg/L, the temperature was 37℃ for 48h. Of the 115 MTB strains, 87 strains were susceptible to PZA and 28 strains were resistant to PZA with BacT/ALLET 3D system while 90 strains were susceptible to PZA and 25 strains were resistant to PZA with PhaB. The 85 strains were susceptible to PZA and 24 strains were resistant to PZA with both two methods. The concordance rate of the determination result was 94.78％(109 strains), and the discrepancy rate was 5.22％(6 strains). If the determination result by BacT/ALERT 3D was taken as the judgment standard, the sensitivity, specificity, positive and negative predictive value as well as overall accuracy of PhaB assay for the detection of PZA resistance was 85.71(24/28), 97.7 ％ (85/87), 96 ％ (24/25), 94.44 ％ (85/90) and 94.78％ (109/115), respectively. [Conclusion] The PhaB assay for the detection of PZA resistance needs only 2～ 3 days, simple operation and no special instrument, so it can be taken as the rapid method for screening PZA re sistance of MTB.