Low rifampicin and early signs of next-line drug resistances: findings from Madagascar’s 2023–24 nationwide drug resistance survey

Abstract Madagascar’s first national drug-resistance survey (2005-06) reported multidrug-resistant tuberculosis (MDR-TB) in 0.2% of new and 3.4% of retreatment patients. To generate updated resistance estimates, a national cross-sectional, cluster-randomised survey was conducted across 36 diagnostic and treatment centres between April 2023 and April 2024. Bacteriologically confirmed pulmonary TB patients were enrolled and sputum specimens collected for drug-resistance testing, including culture, line-probe assay, Xpert MTB/RIF Ultra, and phenotypic drug-susceptibility testing. Of 2,250 enrolled patients, 1,987 were new (88.3%) and 263 were previously treated (11.7%). Weighted prevalence of rifampicin resistance was 0.2% (95% CI 0.1–0.7%) among new patients and 3.7% (95% CI 1.7–7.8%) among previously treated patients, reflecting stability since the 2005-06 survey. No pre-XDR or XDR-TB was detected. However, resistance to bedaquiline or linezolid was found in 2 of 40 new patients and 2 of 11 retreatment patients among rifampicin- and/or isoniazid-resistant isolates. Overall, the findings indicate a stable and contained RR-TB burden in Madagascar. Sustaining this outcome will require continued investment in case detection, drug-susceptibility testing, effective treatment, and routine resistance surveillance.