Evaluation of the line probe assays for the detection of multidrug-resistant tuberculosis in smear-positive suptum specimens

Objective To evaluate the performance of the line probe assays(LPAs) for rapid detection of Mycobacterium tuberculosis complex and their resistance to rifampicin and isoniazid directly in smear-positive sputum specimens.Methods LPAs was used for detecting Mycobacterium tuberculosis complex and their resistance to rifampicin and isoniazid directly in 193 cases smear-positive sputum specimens,and the LPAs results were compared with the DST results obtained by MGIT 960 system and DNA sequencing analysis of rpoB,katG,inhA and oxyR-ahpC.We evaluated the sensitivity,specificity and agreement rates of LPAs for the detection of multidrug-resistant tuberculosis in smear-positive suptum specimens.The statistical analysis was performed by kappa test.Results The sensitivity of LPAs for detection of Mycobacterium tuberculosis complex in smear-positive sputum specimens was 100.0%.The sensitivity of LPAs for detection of rifampicin resistance,isoniazid resistance and MDR-TB in smear-positive sputum specimens were 96.0% (48/50),92.8% (64/69) and 90.0%(45/50),respectively.The specificity of LPAs for detection of rifampicin resistance,isoniazid resistance and MDR-TB in smear-positive sputum specimens were 99.3% (142/143),100.0% (124/124) and 99.3% (142/143), respectively.The agreement rates of rifampicin resistance,isoniazid resistance and MDR-TB were 98.4% (190/193), 97.4% (188/193) and 96.9% (187/193), respectively.Conclusion The LPAs is a rapid and reliable tool for the rapidly direct detection of Mycobacterium tuberculosis complex and their resistance to rifampicin and isoniazid in smear-positive sputum specimens. The rapid turnaround time of the test should enable the optimization of the therapy of these patients before confirmatory culture results are available.