Antibiotics 107.891, its factor A1 and A2, pharmaceutically acceptable salts and compositions, and use thereof.

The invention relates to an antibiotic substance of microbial origin, arbitrarily denominated 107891 which is produced by fermentation of Microbispora sp. ATCC PTA-5024, the pharmaceutically acceptable salts and compositions thereof, and their use as an antibacterial agent having inhibitory activity versus susceptible microbes.