Therapeutic effects of cefozopran on polymicrobial infections associated with Enterococcus faecalis in a Rat pyometra model

Abstract

Enterococcus faecalis plays an important role as a pathogen in polymicrobial infections. We evaluated the efficacy of cefozopran (CZOP) using polymicrobial pyometra rats. Rats were infected with a mixed intrauterine inoculation of E. faecalis plus either Bacteroides fragilis or Prevotella bivia (minimal inhibitory concentration of CZOP; E. faecalis: 6.25 micrograms/ml, B. fragilis: 12.5 micrograms/ml, P. bivia: 12.5 micrograms/ml). Immediately after inoculating 10(5) CFU of each organism/rat, CZOP (either 40 mg/kg, i.v., q.i.d., for 5 days or 80 mg/kg, i.v., b.i.d., for 5 days) was administered. The intrauterine inflammatory change and bacterial counts in the CZOP-treated group were compared with those in the nontreated control group. CZOP significantly (p < 0.01) decreased the bacterial counts except for B. fragilis in the regimen of 80 mg/kg b.i.d. However, the 40 mg/kg, q.i.d., regimen significantly (p < 0.05) reduced bacterial counts compared to 80 mg/kg, b.i.d. These results suggest that CZOP in a more divided dose is efficacious for the treatment of polymicrobial infections associated with E. faecalis in pyometra.