The microbiology of postoperative peritonitis

Postoperative peritonitis carries a higher risk of complications and mortal ity than does community-acquired disease. Little, however, is known about t he specific microbiology of this condition. To gain insight into this probl em, the microbiological findings of 67 patients with postoperative peritoni tis were compared with those of 68 patients with community-acquired periton itis. In a comparison of postoperative peritonitis with community-acquired disease, the number of isolates of enterococci (23 versus 6) and Enterobact er species (13 versus 4) were increased and the number of isolates of Esche richia coli (21 versus 42) were reduced. Antibiotic therapy before reinterv ention increased the number of resistant organisms at relaparotomy (33% ver sus 8%). The in vitro efficacy of the primary antibiotic or combination of drugs did not affect mortality rates (40% versus 38% after effective and in effective treatment, respectively). Thus, the microbiology of postoperative peritonitis differs significantly from that of community-acquired disease, and specific antibiotic therapy is required, despite the doubtful impact o n survival.