[Sensitivity of actinomycetes of the genus Actinomadura to antibiotics].

Sensitivity of 46 strains of Actinomadura representing 27 species was studied with respect to 7 antibiotics. The minimum inhibitory concentrations of the antibiotics with respect to various species of Actinomadura varied within wide ranges, i. e. from 0.1 to 100 micrograms/ml, except levorin, and antifungal antibiotic which did not inhibit the growth of any of the strains even in the highest concentration (100 micrograms/ml). The cultures of the "dassonvillei" type proved to be the most sensitive to the antibiotics. Their sensitivity spectra were very close to those of Norardiopsis dassonvillei. A. carminata, an organism producing carminomycin, was most resistant to the antibiotics. Kanamycin, streptomycin, rifampicin, olivomycin and bruneomycin inhibited the growth of some Actinomadura species even in very low concentrations (1/2 g/ml) and thus may be used for selective screening only of definite Actinomadura species. The Actinomadura cultures were most resistant to rubomycin. All of the Actinomadura strains produced satisfactory growth on media containing this antibiotic in concentrations up to 10 micrograms/ml. Rubomycin in concentrations nor higher than 10 micrograms/ml is recommended to be used for isolation of Actinomadura cultures from soil samples.