Lyndel Singh

Background/Objectives: Access to accurate tuberculosis (TB) diagnostics remains limited, particularly in high-burden settings. The Pluslife MTB assay is among the first molecular tests specifically designed for swab-based detection of Mycobacterium tuberculosis complex (MTBC) and offers near point-of-care use. Methods: We conducted a prospective diagnostic accuracy study in South Africa to evaluate the performance of the Pluslife assay on tongue swabs (TSs) and sputum swabs (SSs) among symptomatic and asymptomatic adults. Results were compared against liquid culture as the reference standard and Xpert MTB/RIF Ultra (Xpert Ultra) as a comparator. Operational characteristics and ease-of-use were assessed through structured observation and Likert-scale scoring by testing personnel. Results: Of the 256 participants enrolled, 92 [36%] were people with HIV (PHIV) and 217 were included in the final analysis. Culture confirmed TB in 41/217 (19%). Pluslife on SSs demonstrated a sensitivity of 85% (95% CI: 70.8–94.4), compared to 83% (95% CI: 67.9–92.8), for Xpert Ultra on sputum and detected one additional case (paired analysis, p = 1.000). Sensitivity on TSs was lower (63%, 95% CI: 46.9–77.9), particularly among PHIV. Specificity exceeded 97% across specimen types. Concordance on TSs between Pluslife and Xpert Ultra increased with higher bacterial loads. Operational evaluation showed short hands-on time and high ease-of-use scores, though limitations were noted for patient identifier recording and troubleshooting on the Pluslife MiniDock device. Conclusions: The Pluslife MTB assay on SSs demonstrated good diagnostic accuracy and favorable usability in this study. Tongue swabs remain feasible but less reliable, supporting sputum as the preferred first specimen for TB diagnosis.

Background/Objectives: Accurate and rapid detection of Mycobacterium tuberculosis complex (MTBC) and drug resistance is essential for effective tuberculosis (TB) management, particularly in high-burden settings. The Cobas^® MTB and Cobas MTB/RIF-INH assays are moderate-complexity nucleic acid amplification tests that detect MTBC and resistance to rifampicin (RIF) and isoniazid (INH). Methods: This study evaluated the clinical diagnostic performance of the Cobas assays on sputum, using liquid culture as the reference standard and Xpert MTB/RIF Ultra (Xpert Ultra) for comparison. Diagnostic accuracy of the Cobas MTB assay on tongue swabs (TS) was also assessed. Results: In a study population (n = 354) with 56% HIV prevalence, the overall sensitivity and specificity of Cobas MTB on sputum was 93.8% (95% CI: 84.8–98.3) and 100% (95% CI: 98.7–100) compared with culture. The assay showed almost perfect agreement with Xpert Ultra (Cohen’s kappa = 0.904). Among HIV-positive participants, sensitivity was 88.2% (95% CI: 72.5–96.7). RIF resistance profiling by Cobas MTB/RIF-INH was fully concordant with culture and Xpert Ultra. Three INH-resistant cases were missed, likely due to genotypic–phenotypic discordance. Although specimen numbers were small, TS demonstrated better diagnostic accuracy when using a diluted (66%) microbial inactivation solution. Conclusions: The Cobas MTB and MTB/RIF-INH assays demonstrated high diagnostic accuracy compared to culture and Xpert Ultra on sputum. Findings support TS as an alternative specimen type for MTBC detection using an optimized protocol. These findings underscore the potential of the Cobas assays as reliable alternatives for TB and resistance diagnostics, particularly in settings where rapid, accurate detection of MTBC and RIF or INH resistance is crucial.

Background/Objectives: Tuberculosis (TB) and SARS-CoV-2 share similar symptoms and transmission routes. In early 2021, USAID and Stop TB Partnership recommended an integrated approach for simultaneous COVID-19 and TB testing in high TB burden countries for individuals with respiratory symptoms. In this evaluation, we tested a single sputum for both SARS-CoV-2 and Mycobacterium tuberculosis complex (MTBC) from participants at two healthcare facilities in South Africa. The diagnostic accuracy of the Xpert Xpress SARS-CoV-2 (Xpress) assay using a sputum swab capture method was assessed by comparing the results with routine SARS-CoV-2 testing, while also determining the prevalence of TB and TB-COVID-19 co-infection in the study population. Methods: A total of 2274 individuals were screened for enrolment. Eligibility included the presence of respiratory symptoms, close contact with a person with TB, TB diagnosis in the last two years or a person living with HIV. Sputum from 1032 participants was tested on the Xpress assay using a swab capture method while residual sputum was tested on the Xpert MTB/RIF Ultra assay for MTBC and rifampicin-resistance detection. Concordance between the Xpress assay and routine SARS-CoV-2 testing was assessed. Results: The Xpress assay detected SARS-CoV-2 in 183/1032 (18%) participants, TB was detected in 35/1032 (3%) participants and 10/1032 (1%) participants were co-infected with TB and COVID-19. The Xpress assay showed substantial agreement with routine testing (Kappa: 0.755). Conclusions: The study findings underscore a substantial identification of TB and rifampicin-resistant TB that would have been missed if bi-disease testing was not performed. In addition, the sputum swab capture method demonstrated reliable performance for SARS-CoV-2 detection.

Background/Objectives: Both tuberculosis (TB) and SARS-CoV-2 share similar symptoms and transmission routes. In early 2021, USAID and Stop TB Partnership recommended an integrated approach for simultaneous COVID-19 and TB testing in high TB burden countries, using a nasopharyngeal swab and sputum for individuals with respiratory symptoms. We extended this in a clinical evaluation, testing a single sputum for both SARS-CoV-2 and Mycobacterium tuberculosis complex (MTBC) at two healthcare facilities in South Africa. Methods: A total of 2274 individuals were screened for enrolment. Eligibility included the presence of symptoms suggestive of either TB or COVID-19 infection, close contact with a person with TB, TB diagnosis in the last two years or a person living with HIV. Sputum from 1032 participants were tested on the Xpert Xpress SARS CoV-2 assay (Xpress) using a swab capture method while residual sputum was tested on the Xpert MTB/RIF Ultra assay for MTBC and rifampicin-resistance detection. Results: The Xpress assay detected SARS CoV-2 in 183/1032 (18%) participants, TB was detected in 35/1032 (3%) participants and 10/1032 (1%) participants were co-infected with TB and COVID-19. Conclusions: The study findings underscore a substantial identification of TB and Rifampicin-resistant TB that would have been missed if bi-disease testing was not performed. In addition, the sputum swab capture method for SARS-CoV-2 detection showed substantial agreement with routine testing.