噬菌体生物扩增法快速测定结核分枝杆菌卷曲霉素耐药性的研究

目的 建立快速测定结核分枝杆菌卷曲霉素耐药性的噬菌体生物扩增法,并探讨其在结核分枝杆菌卷曲霉素耐药性测定中的应用价值。方法 应用噬菌体生物扩增法测定112株结核分枝杆菌卷曲霉素耐药性,并与绝对浓度法结果进行比较,对不符合的菌株采用Bactec MGIT 960测定其最低抑菌浓度(MIC)。以细菌接种量为10^-3mg/ml,药物浓度5μg/ml、37℃作用24 h为药敏试验条件。结果 噬菌体法测定112株结核分枝杆菌临床分离株卷曲霉素敏感91株、耐药21株,绝对浓度法敏感92株、耐药20株;两法测定均为敏感89株、均为耐药18株。在5株噬菌体法与绝对浓度法测定结果不符的菌株中,3株噬菌体法与MIC测定结果相符合。如以绝对浓度法药敏结果为判断标准,则噬菌体法测定卷曲霉素耐药性的敏感性为90%(18/20),特异性为96.7%(89/92),阳性预测值为85.7%(18/21),阴性预测值为97.8%(89/91),准确性为95.5%(107/112)。结论噬菌体生物扩增法测定卷曲霉素耐药性简便快速,只需2 d时间,操作不需特殊仪器设备,具有很高的敏感性和特异性,可作为MTB的卷曲霉素耐药性快速筛选方法,建议临床推广应用。

Rapid detection for capreomycin resistance in clinical isolates of Mycobacterium tuberculosis by phage amplified biological assay

Objective To develop a rapid method to detect Mycobacterium tuberculosis(MTB) resistance to capreomycin by phage biologic amplification,and evaluate its application value.Methods Using Absolute concentration method as control,112 MTB isolates were detected their resistance to capreomycin.If the result is inconsistent,its capreomycin MIC was determined using Bactec MGIT 960.Test condition is as follow: 10^-3mg/ml MTB inoculation,capreomycin concentration 5μg/ml,incubate at 37℃ for 24 hours.Results Of 112 MTB isolates,91 were capreomycin-sensitive and 21 were capreomycin-resistance by phage biologic amplification assay;92 were capreomycin-sensitive and 20 were capreomycin-resistance by the Absolute concentration method.Comparing the Results between these two methods,89 capreomycin-sensitive and 18 capreomycin-resistance isolates were consistent.Of 5 isolates with inconsistent results,the Results from phage biologic amplification assay in 3 isolates were consistent with that from MICs.Using the Absolute concentration method as control,the sensitivity,specificity,positive predictive value,negative predictive value,and diagnostic accuracy of detection of capreomycin resistance by phage biologic amplification assay were 90%(18/20),96.7%(89/92),85.7%(18/21),97.8%(89/91),and 95.5%(107/112),respectively.Conclusions It is sensitive,specific,simple and quick to detect the capreomycin resistance in MTB by phage biologic amplification assay,which needs 2 days and do not require special equipments.