The influence of cefpodoxime proxetil on the intestinal bacterial flora

The influence of cefpodoxime proxetil (CPDX-PR, CS-807), a new oral cephalosporin, on the intestinal bacterial flora was studied in tetra-contaminated mice and in pediatric patients. CPDX-PR dry syrup was administered at a dose of 10 mg/kg once a day for 5 consecutive days to mice contaminated with 4 different species of bacteria: Escherichia coli, Enterococcus faecalis, Bacteroides fragilis and Bifildobacterium breve. No notable changes were observed in fecal viable cell counts except that slight decreases of E. coli counts were observed on the days 3 to 5 after starting administration. The subjects in the pediatric study were 5 children with infections, 3 boys and 2 girls at ages from 1 year 1 month to 6 years 10 months, with their body weights ranging from 9.3 to 23.8 kg. CPDX-PR dry syrup was administered at a dose between 3.0 to 3.7 mg/kg, 3 times a day for 4 to 7 days. Although some variations of the fecal bacterial flora were noticed between subjects during the administration of CPDX-PR, no notable changes were observed in major aerobic and anaerobic bacteria such as Enterobacteriaceae, Enterococcus, Bacteroides and Bifildobacterium in 4 of the 5 cases. Large decreases in Streptococcus, Enterobacteriaceae, Bifidobacterium, Eubacterium and anaerobic cocci and an increase in Enterococcus were observed in the other case. There was no case in which glucose non-fermenting Gram-negative rods and fungi became predominant. Regarding Enterobacteriaceae, transitory bacterial replacement was observed within the genus. Fecal concentration of CPDX during the administration of CPDX-PR was extremely low or below the detectable limit except one specimen from a case in which intestinal bacterial flora showed remarkable changes. From the above, CPDX-PR appears to be a drug with a relatively small influence on the intestinal bacterial flora.