[Microbial diagnosis of atypical mycobacteria]

The introduction of the radiometric system in the diagnostic of tuberculosis caused an increase of positive specimens and shortened the time of detection markedly. This is true for strains of tuberculosis complex and especially atypical mycobacteria. The majority of these is highly resistant to drugs. Therefore, the conventional method of susceptibility tests gives no relevant results for therapy. These are obtained when combinations of drugs are tested. The most important character of atypical mycobacteria is optional pathogenicity. This is why one has to decide for each isolation whether an infection has to be assumed or a colonization only. Atypical mycobacteria are present in the environment of men and are able to multiply under unfavourable conditions. Therefore, they are a potential hazard for men.