A-16686, a new antibiotic from Actinoplanes. II. Biological properties.

A-16686, a new glycoproteide antibiotic obtained from fermentation of an Actinoplanes strain, is active against Gram-positive aerobic and anaerobic bacteria; MIC values ranged from 0.016 to 2.0 micrograms/ml. A-16686 is bactericidal for growing cells of Staphylococcus aureus, S. epidermidis, Streptococcus faecalis, S. faecium, S. mutans, S. mitis and S. sanguis. There is no cross-resistance with clinically used antibiotics. A-16686, administered subcutaneously, is very effective in experimental S. pyogenes and S. pneumoniae septicemias in the mouse.