Abstract:

Objective To investigate the value of PCR-reverse dot blot (RDB) hybridization in detecting the drug resistance of Mycobacterium tuberculosis(MTB) in sputum specimens of retreatment smear-positive pulmonary tuberculosis patients. Methods Sputum specimens from 400 retreatment smear-positive pulmonary tuberculosis patients diagnosed and treated in Shanghai Pulmonary Hospital from June 2015 to January 2019 were collected. The amount of each specimen was more than 2 ml. The same sputum specimen of each patient was tested for drug resistance detection using PCR-RDB, Gene Xpert MTB/RIF and Micropore-plate method (MicroDST). Three hundred and fifty-seven cases (strains) were finally included. The results of MicroDST were used as reference standard to evaluate the performance of PCR-RDB. Results Based on reference standard, the sensitivity, specificity, positive predictive value, negative predictive value, coincidence rate and Kappa value of PCR-RDB in detecting rifampicin resistance of MTB were 97.5% (115/118), 97.1% (232/239), 94.3% (115/122), 98.7% (232/235), 97.2% (347/357) and 0.937; the sensitivity, specificity, positive predictive value, negative predictive value, coincidence rate and Kappa value of PCR-RDB in detecting isoniazid resistance of MTB were 82.5% (113/137), 99.1% (218/220), 98.3% (113/115), 90.1% (218/242), 92.7% (331/357) and 0.841; the sensitivity, specificity, positive predictive value, negative predictive value, coincidence rate and Kappa value of PCR-RDB in detecting streptomycin resistance of MTB were 86.5% (115/133), 99.1% (222/224), 98.3% (115/117), 92.5% (222/240), 94.4% (337/357) and 0.877; the sensitivity, specificity, positive predictive value, negative predictive value, coincidence rate and Kappa value of PCR-RDB in detecting ethambutol resistance of MTB were 60.7% (37/61), 98.6% (292/296), 90.2% (37/41), 92.4% (292/316), 92.2% (329/357)and 0.682. Conclusion PCR-reverse dot blot hybridization shows a good capability in detecting the drug resistance of MTB in sputum specimen of retreatment smear-positive pulmonary tuberculosis patients.

Key words: Mycobacterium tuberculosis, Tuberculosis, multidrug-resistant, Microbial sensitivity tests, Polymerase chain reaction, Two-hybrid system techniques, Evaluation studies, Data interpretation, statistical