Mycobacterium tuberculosis drug-resistance in previously treated patients in Ouagadougou, Burkina Faso

Background: Tuberculosis drug-resistance becomes common in sub-Saharan Africa; however, very few data are available in Burkina Faso. The aim of this study is to assess the acquired resistance of Mycobacterium tuberculosis complex strains identified in TB patients to four first-line drugs in Ouagadougou. Methods: One hundred and ten (110) pulmonary tuberculosis patients with acid-fast bacilli-positive sputum and in situation of failure, relapse, or treatment abandonment were included in the study. Ninety six strains, including 92 (95.8%) M. tuberculosis and 4 (4.2%) M. africanum, were isolated from the sputum samples of these patients. Their drug susceptibility testing was performed using the proportion method. The first-line drugs tested were isoniazid (INH), streptomycin (STR), ethambutol (EMB), and rifampicin (RIF). Results: The overall drug-resistance rate of M. tuberculosis was 67.4% (n=60), including 3.4% to one drug, 18% to two, 10.1% to three, and 35.9% to four drugs. The resistance to INH, RIF, EMB, and STR were 67.4%, 51.7%, 50.6%, and 44.9%, respectively. Two strains of M. africanum were resistant to all drugs. Forty-six (51.7%) strains were multidrug-resistant (resistant to at least INH and RIF). Conclusions: In previously treated patients, the level of resistance of M. tuberculosis complex to commonly used anti-tuberculosis drugs is very high in Ouagadougou. Our results showed that multidrug-resistant tuberculosis could be a public health problem in Burkina Faso