Abstract: 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.

Key words: mycobacterium, tuberculosis, drug susceptibility test, phage, capreomycin