Aerobic and anaerobic bacteriology of pilonidal cyst abscess in children.

Aspirates of pus from pilonidal abscesses in 25 children were studied for aerobic and anaerobic bacteria. A total of 76 isolates (63 anaerobic and 13 aerobic) were recovered from the patients, accounting for 2.52 anaerobes and 0.52 aerobes per specimen. Anaerobic organisms were recovered from all the specimens, and in eight cases (32%) they were mixed with aerobic organisms. The predominant anaerobic organisms were Bacteroides sp (36 isolates, including ten B fragilis group and ten B melaninogenicus group), Gram-positive anaerobic cocci (16). Fusobacterium sp (five), and Clostridium sp (four). The predominant aerobic organisms were Escherichia coli (four) and group D streptococci, alpha-hemolytic streptococci, and Proteus sp (two of each). We believe this study is the first to demonstrate the mixed anaerobic and aerobic bacteriology of pilonidal cyst abscesses in children.