INVESTIGATION OF THE POTENTIAL ROLE OF ENTEROCOCCUS-FAECALIS IN THE PATHOPHYSIOLOGY OF EXPERIMENTAL PERITONITIS

Two nonfatal models of peritonitis differing by the duration and the s everity of the disease were studied in rats by implantation of Escheri chia coli and Bacteroides fragilis with or without increasing concentr ations of Enterococcus faecalis. Results were evaluated at 3 or 6 days after inoculation. The highest enterococcal concentrations (10(9) cfu /ml) enhanced the severity of the infection, evident by increased emac iation, increased peritoneal counts of E. coli and B. fragilis, and in creased frequency of E. coli and B. fragilis bacteremia compared with enterococcus-free animals. Six therapeutic regimens (low-dose amoxicil lin + low-dose gentamicin, high-dose amoxicillin + high-dose gentamici n, pefloxacin, ornidazole, pefloxacin + ornidazole, imipenem + gentami cin) were tested. All treatments failed to eradicate E. faecalis excep t the combination pefloxacin + ornidazole, which achieved a significan t reduction of local bacterial counts and suppressed bacteremia. Enter ococcus played an important role in the mechanisms of bacterial synerg y in experimental peritonitis. However, eradication of enterococcus di d not seem possible by conventional antienterococcal therapy.