Aerobic and anaerobic bacteriology of subcutaneous abscesses

Pus from 84 patients with subcutaneous abscesses was examined for aerobic and anaerobic bacteria: organisms were recovered from 70 (83.3 per cent). In 13 no organisms were seen in the Gram-stained smears and the cultures showed no bacterial growth. Staphylococcus aureus was the most prevalent organism (n = 44), isolated in 43 in pure culture, in marked contrast to the anaerobic organisms which almost invariably were associated with mixed cultures. All patients were treated by the primary suture method. Half of them were not given preoperative antibiotics and 3 developed bacteraemia and 1 septicaemia. Blood isolates were of S. aureus of the same phage type as pus isolates. The other patients received one infection of 300 mg of clindamycin phosphate 30 min to 1 h before surgery. From this group only one patient, with a perianal abscess, developed Escherichia coli bacteraemia. The levels of clindamycin in the abscess aspirate were inhibitory for S. aureus, bacteroides, streptococci and other Gram-positive bacteria but not for E. coli.