Prospective evaluation of thin-layer agar colour test in routine diagnosis of multidrug-resistant TB

• Published in: The international journal of tuberculosis and lung disease Vol. 28; no. 8; pp. 387 - 394
• Main Authors: Klaos, K., Agejeva, A., Hurt, K., Kummik, T., Kurve, A., Nirk, J., Pehme, L., Remets, O., Sasi, S., Tann, A., Altraja, A.
• Format: Journal Article
• Language: English
• Published: France International Union Against Tuberculosis and Lung Disease 01.08.2024; International Union against Tuberculosis and Lung Disease (IUATLD)
• Subjects: Adult; Agar; Antibiotics; Antitubercular Agents - pharmacology; Bronchoalveolar Lavage Fluid - microbiology; Bronchus; Color; Computed tomography; Culture Media; Diagnostic systems; Direct Drug Susceptibility Test; Female; Humans; In-House Tuberculosis Diagnosis; Isoniazid; Lavage; Levofloxacin; Male; Medical diagnosis; Microbial Sensitivity Tests; Middle Aged; Multidrug resistance; Multidrug resistant organisms; Mycobacterium tuberculosis - drug effects; Mycobacterium tuberculosis - isolation & purification; Performance evaluation; Pleural Effusion - diagnosis; Pleural Effusion - microbiology; Pleural fluid; Prospective Studies; Pulmonary Tuberculosis Detection; rifampicin-resistant tuberculosis; Rifampin; Sensitivity analysis; Sensitivity and Specificity; Sputum; Sputum - microbiology; Time Factors; Tuberculosis; Tuberculosis, Multidrug-Resistant - diagnosis; Tuberculosis, Multidrug-Resistant - drug therapy
• ISSN: 1027-3719; 1815-7920; 1815-7920
• DOI: 10.5588/ijtld.23.0536

BACKGROUND This study evaluated the diagnostic performance of the thin-layer agar MDR/XDR-TB Colour Test (CT), a Mycobacterium tuberculosis complex (MTBC) detection and direct drug susceptibility testing (DST) method with routine sputum, bronchoalveolar lavage and pleural fluid specimen. METHODS In a prospective study, the time and rate of MTBC detection were compared between CT, Löwenstein-Jensen, and MGIT media. Times until DST result, sensitivities, and specificities were evaluated between CT and MGIT 960 indirect DST. RESULTS The cultivation of 177 pulmonary specimens resulted in 83 MTBC-positive cultures. The sensitivity of CT for MTBC detection was 81.3% with a median time of 20 days compared to 13 days and 93.5% for MGIT. The sensitivity of CT for DST results was 100% for isoniazid and levofloxacin and 94.7% for rifampicin. The specificities for isoniazid and rifampicin DST were 97.3% and 98.0% for levofloxacin. The median time until a DST result was significantly shorter with CT than the BACTEC MGIT 960 system, 20 and 27 days, respectively, independent of the specimen type used. CONCLUSIONS The CT is a highly accurate and fast initial diagnostic test for high-incidence settings and could also be used as a first culture and direct DST in peripheral settings.