Rifampicin mono-resistant Mycobacterium tuberculosis in Bujumbura, Burundi: results of a drug resistance survey.

Bujumbura, Burundi. To determine resistance levels of Mycobacterium tuberculosis (TB) to the main anti-tuberculosis drugs after 11 years of a DOTS programme using a WHO-recommended partially intermittent 6-month rifampicin (RMP) first-line regimen and fixed-dose drug combinations (FDCs). Drug susceptibility testing of systematic samples of M. tuberculosis isolated from newly registered sputum smear-positive cases in the capital during a 15-month period (2002-2003). Of 496 strains from new cases, 16.1% showed resistance to any drug, 6.3% to isoniazid (INH), 2.0% to RMP (1.4% multidrug-resistant TB [MDR-TB]), 13.3% to streptomycin and 1.6% to ethambutol. Among 69 strains from previously treated cases, the prevalence of resistance was 30%, 19%, 15% (12% MDR-TB strains), 25% and 6%, respectively. Levels of drug resistance in Bujumbura are higher than average for Africa, despite long-term use of the DOTS strategy with FDCs and a ban on sales of TB drugs. Most worrying is the appearance of MDR-TB and RMP-resistant, INH-susceptible strains in new cases. Although a survey cannot prove that high HIV prevalence, elevated levels of resistance to some other drugs and irregular intake allowed acquisition of drug resistance, the effectiveness and safety of 6-month regimens with (partially) intermittent RMP throughout under such conditions should be investigated.