Can rifampicin use be safely extended? Evidence for non-emergence of resistant strains of Mycobacterium tuberculosis.

Data on the incidence of primary resistance to rifampicin in Mycobacterium tuberculosis strains have been collected from various countries. Strains isolated from those countries where rifampicin is used for both tuberculous and non-tuberculous conditions (Italy, Argentina, Brazil, and Spain) did not show a higher incidence of primary resistance than did strains from other countries (France, U.K., and U.S.A.) where rifampicin use is confined to tuberculosis. It is concluded that there is no evidence to justify fears of an increased incidence of resistance to rifampicin in M. tuberculosis if rifampicin were used discreetly for treating non-tuberculous infections.