Evaluation of biochip system in determining isoniazid and rifampicin resistances of mycobacterium tuberculosis in sputum samples.

OBJECTIVE: To evaluate a biochip system in determining isoniazid and rifampicin resistances of Mycobacterium tuberculosis in sputum samples in a Chinese population. METHODS: We assembled 907 sputum smeared positive specimens of tuberculosis patients in total. Each sample would be separated into two parts for culture and biochip assay simultaneously. And those cultured positive and having full drug resistance results would be used as reference. The McNemar χ² test was adopted for evaluating the paired 2×2 table. RESULTS: Compared with drug sensitivity test, the agreement rates of the two methods in detecting rifampicin and isoniazid resistances were 93.37% and 94.49%, respectively. The sensitivity and specificity of biochip in detecting isoniazid were 74.31% and 96.92%, respectively. Meanwhile, the sensitivity and specificity for rifampicin were 79.76% and 96.53%, respectively. For multi-drug resistance, the sensitivity and specificity were 64.62% and 97.75%, respectively. CONCLUSIONS: The biochip system is a rapid and accurate method for drug resistant tuberculosis diagnosis using sputum samples directly, especially for rifampicin resistance detection.