Evaluation of a novel line-probe assay for genotyping-based diagnosis of Mycobacterium tuberculosis in Thailand.

SETTING

The Supranational Tuberculosis Reference Laboratory (NTRL), Bangkok, and Chiangrai Prachanukroh Hospital, Chiangrai, Thailand

OBJECTIVE

To evaluate the diagnostic performance of newly developed line-probe assay (LiPA) kits in tuberculosis (TB) endemic settings.

DESIGN

LiPA kits were used to evaluate 404 clinical isolates of Mycobacterium species and 163 sputum samples in Thailand.

RESULTS

LiPA kits were able to identify M. tuberculosis, M. avium, M. intracellulare and M. kansasii with 100% sensitivity and specificity when compared with the commercially available AccuProbe assay. Testing of the LiPA kits for their ability to detect mutations in clinical isolates resistant to anti-tuberculosis drugs such as rifampicin, isoniazid, pyrazinamide and fluoroquinolones showed that the assay had very high sensitivity (65.9-100%) and specificity (98.2-100%) compared with drug susceptibility testing and DNA sequencing. LiPA had a sensitivity of 75.0-85.7% and a specificity of 96.4-100% in testing clinical sputum samples.

CONCLUSION

The novel LiPA kits have high sensitivity and specificity, and may enhance the rapid detection of first- and second-line anti-tuberculosis drug resistance, improving the selection of suitable chemotherapy agents to treat multidrug-resistant and extensively drug-resistant TB.