Background Treatment for Multi-Drug Resistant Tuberculosis (MDR-TB) is long and costly. Currently, there are limited effective and affordable treatment response monitoring tools. We set to evaluate the performance of alternative bacteriological measures of response to therapy during the initial 16 weeks of MDR-TB treatment.

Methods In a prospective study of MDR/RR-TB in Uganda, all smear-positive participants were enrolled for treatment response monitoring using Concentrated Fluorescent Microscopy (CFM), Fluorescein-di-acetate (FDA) AFB vital smear microscopy, and 16S rRNA-based assay in a Molecular bacterial load assay (TBMBLA) and Mycobacterial Growth Indicator Tube (MGIT) as alternative bacteriological measures. Pooled early morning and spot sputum samples were processed at weeks 0 (pre-treatment), 2, 4, 6, 8, 12, and 16. Solid culture, Middle Brook 7H11 selective (MB7H11S) colony-forming units were used as the standard measure of treatment response. Bacteriological conversion to negative by the alternative tests was assessed against MB7H11 at weeks 12 and 16 of treatment.

Results A total of 59 participants were enrolled, of whom 58 provided sputum samples at baseline. Participants were; 64% male, median age (IQR) 33 (28.6–37.4), 44% HIV-positive, and 78% on ART. The underweight (BMI<18.5kg/m2) was 61% and the median BMI (IQR) was 18.1 (17.3–18.6). Bacteriological positive at baseline were n (%); CFM 49 (84.5), FDA 40 (69.0), TB-MBLA 32 (60.4), MGIT 51 (87.9), and MB7H11S was 47 (81.0). Bacteriological conversion to negative at week 12 and week 16 respectively were CFM 92% and 98%, FDA 98% and 98%, TB-MBLA 98% and 100%, MGIT 95% and 93%, MB7H11S 96% and 98%.

Conclusion Our data show that concentrated fluorescent smear microscopy, fluorescein-di-acetate smear microscopy, TBMBLA, and MGIT culture as suitable alternative measures of response to therapy among MDR-TB patients. Efforts should be made to make such methods available for the timely monitoring of patients on MDR-TB regimens.