Rifampicin for non-tuberculous infections?

Large populations of rifampicin-sensitive strains of Mycobacterium tuberculosis have been exposed in vitro to changing concentrations of rifampicin (RIF) in line with changes in the blood level of the drug observed during treatment, and to much lower concentrations. Experiments in which the organism was exposed to either 7 or 14 days of cyclically-changing rifampicin concentrations have resulted in the elimination of the M. tuberculosis test strains without the emergence of RIF resistance. The significance of these laboratory findings is discussed in relation to the debate as to whether rifampicin should be used in short courses for the treatment of non-tuberculous infections or whether it should be withheld for fear of inadvertently generating rifampicin-resistant strains of tubercle bacilli. It is argued that the evidence for withholding rifampicin from use in short courses against non-tuberculous infections is slight.