Abstract:

Objective: To explore the application value of Mycobacterium tuberculosis ribonucleic acid (TB-RNA) detection in evaluating early effectiveness of anti-tuberculosis treatment in patients with pulmonary tuberculosis. Methods: A retrospective analysis was conducted on data of 186 patients admitted to Guangzhou Chest Hospital from January to December 2023, who were diagnosed with pulmonary tuberculosis by BACTEC MGIT 960 liquid culture and had imaging features consistent with active pulmonary tuberculosis lesions. The observation time was 2 months after treatment. TB-RNA test and MGIT 960 culture were performed on sputum/bronchoalveolar lavage fluid (BALF) at the end of 1st and 2nd months of treatment. The consistency between these two tests was analyzed; the differences of imaging improvement between TB-RNA positive and negative patients were compared. The correlations of variables were analyzed using Spearman rank correlation analysis. Results: The positive rate of TB-RNA at admission was 100.00% (186/186); the positive rates of TB-RNA at the end of 1st and 2nd months of treatment were 53.76% (100/186) and 19.35% (36/186), respectively; The positive rates of MGIT 960 were 49.46% (92/186) and 18.28% (34/186), respectively, both showing a downward trend (TB-RNA: χ²=47.474, P<0.001; MGIT 960: χ²=40.373, P<0.001). Using MGIT 960 result as standard, the sensitivity of TB-RNA detection in the 1st month was 93.48% (86/92), the specificity was 85.11% (80/94), and the Kappa value was 0.785; the sensitivity in the 2nd month was 88.24% (30/34), the specificity was 96.05% (146/152), and the Kappa value was 0.824. The effective lesion absorption rate and cavity closure rate of TB-RNA-negative patients were significantly higher than those of TB-RNA-positive patients (effective lesion absorption rate at the 1st month: 69.77% (60/86) vs. 40.00% (40/100), cavity closure rate: 27.91% (24/86) vs. 6.00% (6/100); effective lesion absorption rate at the 2nd month: 86.67% (130/150) vs. 50.00% (18/36), cavity closure rate: 56.00% (84/150) vs. 27.78% (10/36); χ²=16.481, 16.403, 24.011, 9.251, P<0.001, <0.001, <0.001, 0.002); The TB-RNA results were positively correlated with lesion absorption and cavity closure (r=0.428, 0.403 at the 1st month, r=0.451, 0.422 at the 2nd month, all P<0.001). Conclusion: TB-RNA can specifically identify viable bacteria, rapidly and sensitively reflects bacteriological outcome at the early stage of anti-tuberculosis treatment (1-2 months), and is highly correlated with imaging improvement, which can be used as an important marker for the early effectiveness evaluation of pulmonary tuberculosis.

Key words: Tuberculosis, pulmonary, RNA, Treatment outcome, Sensitivity and specificity