Extensively resistant tuberculosis: Four cases in the Republic of Congo.

Extensively drug-resistant (XDR) tuberculosis is currently a major public health problem in most developing countries, including the Republic of Congo, where antituberculosis agents are repeatedly unavailable. We report four cases from by the National Program for Tuberculosis Control in collaboration with its National Reference Laboratory (NRL) of the Republic of Congo. The presence of these highly resistant strains causes therapeutic problems (treatment depends on the profile of individual mutations and the unavailability of new drugs) and public health (major risk of spread of the disease in the community).