Anti-tuberculosis drug resistance among retreatment patients seen at St Peter Tuberculosis Specialized Hospital.

Background: Resistance to first line anti-tuberculosis (TB) drugs is an increasing concern. Drug sensitivity of mycobacterial isolates from patients who failed treatment may indicate the potential sources of spread and the emerging patterns of resistance.

Objective: To determine the prevalence of resistance to the main anti TB drugs among re-treatment cases who had previously received loose drugs or the 3FDC regimen in the intensive phase.

Direct colorimetric assay for rapid detection of rifampin-resistant Mycobacterium tuberculosis.

The colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was standardized for direct detection of rifampin-resistant Mycobacterium tuberculosis in sputum samples. The sensitivity and specificity of the direct MTT assay matched those of the standard indirect susceptibility assay on 7H10 medium, and interpretable results were obtained for 98.5% of the samples within 2 weeks.