[Antibiotic formation in plasmid and plasmid-free strains].

Antibiotic activity of three plasmid and three plasmid-free strains of Bacillus pumilus was studied. The antibiotic activity was found in one plasmid and two plasmid-free strains. It was supposed that both the chromosomic and extrachromosomic genes could participate in regulation of the antibiotic production in Bac. pumilus. It was shown that the antibiotics produced by Bac. pumilus had a very narrow spectrum and inhibited multiplication only of several grampositive bacteria.