Evaluation of Xpert MTB/XDR test for susceptibility testing of Mycobacterium tuberculosis to first and second-line drugs in Uganda

• Published in: PloS one Vol. 18; no. 8; p. e0284545
• Main Authors: Katamba, Achilles, Ssengooba, Willy, Sserubiri, James, Semugenze, Derrick, Kasule, George William, Nyombi, Abdunoor, Byaruhanga, Raymond, Turyahabwe, Stavia, Joloba, Moses L
• Format: Journal Article
• Language: English
• Published: San Francisco Public Library of Science 17-08-2023; Public Library of Science (PLoS)
• Subjects: Antibiotics; Biology and Life Sciences; Care and treatment; Comparative analysis; Diagnosis; Diagnostic tests; Disease susceptibility; Drug resistance; Drugs; Endorsements; Evaluation; Fluoroquinolones; Genotypes; Isoniazid; Medical diagnosis; Medicine and Health Sciences; Mycobacterium tuberculosis; Research ethics; Rifampin; Sensitivity; Sputum; Technicians; Testing laboratories; Tuberculosis; Uganda
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0284545

Drug-Resistant Tuberculosis (DR-TB) is one of the major challenges to TB control. This was a blinded, laboratory-based cross-sectional study using sputum samples or culture isolates. Samples were from patients with rifampicin-resistant-TB and/or with high risk for isoniazid (INH) resistance and/or 2.sup.nd line fluoroquinolones (FQ) and injectable agents (IAs). The diagnostic accuracy of the Xpert.sup.® MTB/XDR test was compared to MGIT960 and the Hain Genotype.sup.® MTBDRplus and MDRsl assays (LPA) as reference DST methods. Factors for laboratory uptake of the Xpert.sup.® MTB/XDR test were also evaluated. Of the 100 stored sputum samples included in this study, 65/99 (65.6%) were resistant to INH, 5/100 (5.0%) were resistant to FQ and none were resistant to IAs using MGIT960. The sensitivity and specificity, n (%; 95% Confidence Interval, CI) of Xpert.sup.® MTB/XDR test for; INH was 58 (89.2; 79.1-95.5) and 30 (88.2; 72.5-96.6) and for FQ; 4 (80.0; 28.3-99.4) and 95 (100; 96.2-100), respectively. Using LPA as a reference standard, a total of 52/98 (53.1%) were resistant to INH, 3/100 (3.0%) to FQ, and none to IA. The sensitivity and specificity, n (%; 95%CI) of Xpert.sup.® MTB/XDR test compared to LPA for; INH was 50 (96.1; 86.7-99.5) and 34 (74.0; 58.8-85.7) for FQ 3 (100; 29.2-100) and 96 (99.0; 94.3-99.9) respectively. The factors for laboratory uptake and roll-out of the Xpert.sup.® MTB/XDR test included: no training needed for technicians with, and one day for those without, previous Xpert-ultra experience, recording and reporting needs were not different from those of Xpert-ultra, the error rate was 4/100 (4%), one (1%) indeterminate rate and test turn-around-time were 1hr/45 minutes. There is high sensitivity and specificity of Xpert.sup.® MTB/XDR test for isoniazid and fluoroquinolones. There are acceptable Xpert.sup.® MTB/XDR test attributes for the test uptake and roll-out.