Influence of sultamicillin on intestinal bacterial flora

Abstract

Effects of sultamicillin (SBTPC) fine granules, a new oral beta-lactam antibiotic, on the intestinal bacterial flora were studied in tetra-contaminated mice and in pediatric patients. SBTPC was administered at a dose of 100 mg/kg once a day for 5 consecutive days to mice contaminated with 4 different species of organisms: Escherichia coli, Enterococcus faecalis, Bacteroides fragilis and Bifidobacterium breve. In all of the 4 species, bacterial populations in feces were markedly reduced on days 4 to 5 after the start of the treatment. Subjects in the pediatric study were 5 children with bacterial infections (4 boys and 1 girl) at ages from 1 year 3 months to 10 years 8 months and with their body weight ranging from 11.8 kg to 35.0 kg. SBTPC fine granule was administered at a dose of 10 mg/kg 3 to 4 times a day for 4 to 7 days. Although there were some variations in the fecal bacterial flora noticed among these subjects during the treatment, populations of main aerobes and anaerobes such as Enterobacteriaceae, Enterococcus, Bacteroides and Bifidobacterium decreased markedly in all cases. These decreases were more pronounced for anaerobes and total numbers of anaerobes were markedly reduced in all cases. Glucose non-fermenting Gram-negative rods and fungi tended to increase with administration of SBTPC fine granule. Although these changes tended to return to pre-dosing state after the cessation of the treatment with SBTPC fine granule, attention must be paid to possible occurrences of diarrhea, superinfection or bleeding tendency when treatment with the drug is continued for a long period of time. Fecal concentrations of both ampicillin and sulbactam during SBTPC fine granule treatment showed relatively high values except 1 sample with a high beta-lactamase activity in feces. These high concentrations suggest the possibility of biliary excretion of absorbed drugs and the possibility of hydrolysis of SBTPC in the intestine due to high pH. Fecal concentrations of the drug also appeared to be closely related to beta-lactamase activity in feces.