A drug sensitivity test strategy for atypical mycobacteria

The value of anti-tuberculosis drugs for the treatment of infections caused by atypical mycobacteria is limited by the high prevalence of drug resistance. From the mycobacteriological point of view, however, nonspecific antibiotics and sulphonamides can also be used for their therapy. Atypical mycobacteria are high heterogeneous in their drug sensitivity patterns and in this respect each strain virtually represents a distinct biological unit. To select suitable drugs for combined treatment advantage should be taken of an analytical quantitative proportional sensitivity test that will allow determination of primary resistant population frequency per million viable mycobacterial units. In each case treatment should be with a combination of drugs in which the frequency of primary resistant populations is 10(-5) or lower.