Limited fluoroquinolone resistance among Mycobacterium tuberculosis isolates from Rwanda:: results of a national survey

Objectives: There is an increasing interest in the possible role of fluoroquinolone antibiotics for the treatment of tuberculosis (TB), but widespread use of these antibiotics for the treatment of other bacterial infections may select for fluoroquinolone-resistant Mycobacterium tuberculosis strains. Methods: We evaluated fluoroquinolone susceptibility using the proportion method (ofloxacin, critical concentration 2.0 mg/L) in isolates from patients enrolled in a national drug resistance survey in Rwanda from November 2004 to February 2005. Results: Of the 701 M. tuberculosis isolates studied, 617 (88%) were susceptible to all first-line drugs, 32 (4.6%) were multidrug-resistant (MDR) and 52 (7.4%) were resistant to one or more first-line drugs but not MDR. Ofloxacin resistance was found in four (0.6%) of the isolates; three of them being MDR and one susceptible to all first-line drugs. Mutations in the gyrA gene were found in all ofloxacin-resistant strains at codons 80 and 94. Conclusions: Our finding is not alarming for Rwanda, but highlights the general risk of producing resistance to fluoroquinolones, jeopardizing the potential for these drugs to be used as second-line anti-TB agents in the programmatic management of drug-resistant TB and creating incurable TB strains.