Abstract:

Objective: To evaluate the performance of InnowaveDX MTB/RIF (InnowaveDX) in detecting Mycobacterium tuberculosis complex (MTBC) and MTB rifampicin resistance. Methods: Using prospective research methods, 104 consecutive patients with tuberculosis related signs/symptoms or suspected tuberculosis according to chest X-ray from March 1 to June 30, 2023 in the Affiliated Hospital of Zunyi Medical University were included as research objects. Among them, 93 cases were diagnosed as tuberculosis (68 cases diagnosed with positive etiology and 25 cases diagnosed with negative etiology), and 11 cases were diagnosed as non-tuberculosis. Sputum, bronchoalveolar lavage fluid, urine, lymph node puncture fluid, cerebrospinal fluid, pus and pleural effusion of the subjects were collected for smear acid fast bacilli staining microscopy, culture, InnowaveDX and GeneXpert MTB/RIF (Xpert) detections, and the detection efficiency of InnowaveDX for tuberculosis and MTB rifampicin resistance was evaluated. Results: Based on etiology and clinical diagnosis, the sensitivity, specificity, consistency and Kappa value of InnowaveDX in detecting tuberculosis were 92.5% (86/93), 100.0% (11/11), 93.3% (97/104) and 0.72 respectively; and those of Xpert were 93.6% (87/93), 100.0% (11/11), 94.2% (98/104) and 0.75, respectively. The positive rates of InnowaveDX and Xpert in detecting sputum samples were both 91.5% (65/71), and the difference was not statistically significant(χ²=0.000, P=1.000); the positive rates of detecting other types of specimens (bronchoalveolar lavage fluid, urine, lymph node puncture fluid, cerebrospinal fluid, pus, and pleural effusion) were 95.5% (21/22) and 100.0% (22/22), respectively, with no statistically significant difference (Fisher’s exact probability method, P=1.000). Based on the results of Xpert testing for MTB rifampicin resistance, the sensitivity of InnowaveDX testing for MTB rifampicin resistance was 97.0% (32/33), the specificity was 92.2% (47/51), and the Kappa value was 0.88. Conclusion: InnowaveDX has good detection efficiency for MTBC and is suitable for different types of specimens. And the results of detecting MTB rifampicin resistance are consistent with Xpert.

Key words: Mycobacterium tuberculosis, Drug resistance, bacterial, Rifampin, Diagnosis