Microbiology of subphrenic abscesses: A 14-year experience

The objective of the review was to study the aerobic and anaerobic microbio logy of subphrenic abscesses in relation with predisposing conditions. A re trospective review of clinical and laboratory data of 52 patients treated b etween 1974 and 1988 was conducted. Forty-three (83%) patients developed th e abscesses after an operative procedure. These included 11 patients after colonic, 9 patients after gastric or duodenal, 7 patients after abdominal t rauma, 7 patients after biliary, and 6 patients after appendix surgery. A t otal of 194 organisms (3.7 isolates/specimen), 83 aerobic (1.6/specimen), a nd 111 anaerobes (2.1/specimen) were recovered. Aerobic bacteria only were recovered in 7 (13%) abscesses, anaerobic bacteria only in 11 (21%), and mi xed aerobic aid anaerobic bacteria in 34 (65%). Polymicrobial infection was present in 47 (90%). The predominant aerobic isolates were Escherichia col i (28 isolates), Enterococcus group D(9), and Staphylococcus aureus (9). Th e predominant anaerobes were Peptostreptococcus species (33 isolates), Bact eroides fragilis group (25), Clostridium species (13), and Prevotella speci es (6). The number of isolates/site varied. The number of anaerobic bacteri a/site outnumbered or was equal to the number of aerobic or facultatives in all instances, except in abscesses after biliary surgery. Their number/sit e was especially hi gh in abscesses after appendectomy, and the number of a erobic and anaerobic bacteria was the lowest after gastric or duodenal surg ery. S. aureus predominated after gastric, duodenal and posttrauma surgery; B. fragilis predominated after colonic, appendix, and postabdominal trauma surgery; Enterococcus group D predominated after biliary surgery; Fusobact erium and Prevotella species predominated after gastric or duodenal surgery ; and Clostridium species predominated after colonic or appendix surgery. T hese data highlight the polymicrobial aerobic-anaerobic nature of subphreni c abscesses and their correlation with predisposing surgery.