Macrolide antibiotics M-4365 produced by Micromonospora. III. In vitro antimicrobial activity of antibiotic M-4365G2 (de-epoxy rosamicin).

Antibiotic M-4365G2 (de-epoxy rosamicin) produced by Micromonospora capillata MCRL 0940 is a new basic 16-membered macrolide antibiotic with activity equal to or superior to erythromycin and josamycin against Gram-positive bacteria. Of interest are the high degree of activity against Gram-negative bacilli and mycoplasmas, and striking inhibitory effects against indole-producing Proteus spp. Bactericidal activity of M-4365G2 is also to be noticed.