Formation of intraperitoneal abscesses by Staphylococcus aureus.

Certain Staphylococcus aureus strains, when inoculated into the peritoneal cavity of mice, were clumped and surrounded by a thick layer of leukocytes. After being enclosed with a connective tissue capsule, the structures histologically resembled staphylococcal abscesses. Of four strains examined, all were destroyed within abscesses, although at different rates. Abscess homogenates possessed bactericidal activity toward staphylococci, and this activity was associated with the sedimentable fraction of the homogenates. Leukocytes did not appear to be responsible for the bactericidal activity. Appreciable quantities of alpha toxin accumulated in these abscesses even without multiplication of the organisms. This model infection offers opportunities for studying some aspects of staphylococcal host-parasite interactions occurring in localized lesions.