Sporeamicin A, a new macrolide antibiotic. III. Biological properties.

Sporeamicin A is a new erythromycin-type antibiotic isolated from a species of Saccharopolyspora. It was active in vitro against a wide variety of Gram-positive bacteria. In vitro studies indicated that the sporeamicin A was stable in the presence of human serum, although it was bound to serum proteins. Sporeamicin A was effective in the mouse protection test against Staphylococcus aureus, Streptococcus pyogenes and Streptococcus pneumoniae. Sporeamicin A attained higher plasma and tissue levels in the rat than did erythromycin stearate.