Abstract:

Objective To evaluate the clinical application value of gene chip technique and linear probe technique (MTBDRplus) in rapid detection of MTB drug resistance. Methods A total of 493 patients with smear-positive pulmonary tuberculosis who were hospitalized in Xi’an Chest Hospital between April 2017 to August 2018 were selected as subjects. The sputum samples with the amount larger than 2 ml were collected. Each sputum sample was examined by gene chip, MTBDRplus and BACTEC MGIT 960 (MGIT 960) techniques, respectively. Meanwhile, the clinical isolates positive in culture and identified as MTB were subjected to MGIT 960 liquid drug susceptibility test. The results of MGIT 960 drug susceptibility test were used as reference standard to evaluate the performance of gene chip technique and MTBDRplus in detecting MTB isoniazid and rifampicin resistance in sputum specimens from smear-positive pulmonary tuberculosis patients. Results A total of 454 cases had the complete susceptibility test results detected by the three detection methods. Based on the results of drug susceptibility test by MGIT 960 method as reference standard, the sensitivity, specificity, and Kappa value of gene chip technique and MTBDRplus for detecting rifampicin resistance were 89.0% (65/73), 96.1% (366/381) and 0.82 as well as 90.4% (66/73), 96.1% (366/381) and 0.83, respectively; the sensitivity, specificity, and Kappa value for detecting isoniazid resistance were 80.2% (93/116), 96.7% (327/338) and 0.80 as well as 81.9% (95/116), 97.0% (328/338) and 0.82, respectively. Among 454 samples of the rifampicin resistance results, 453 cases were detected as the same results using gene chip technique and MTBDRplus, with the coincidence rate of 99.8%; the isoniazid resistance results detected by the two methods were consistent in 445 cases, with the coincidence rate of 98.0%. Conclusion Gene chip technique and MTBDRplus are highly consistent with MGIT 960 drug susceptibility test in detecting MTB rifampicin and isoniazid resistance in sputum specimens from smear-positive pulmonary tuberculosis patients, and both of them can provide rapid and specific drug resistance results.

Key words: Tuberculosis,multidrug-resistant, Microchip analytical procedures, Molecular probe techniques, Rifampin, Isoniazid, Comparative study