[The effect of roxithromycin on the aerobic fecal flora in children]

To evaluate the effect of roxithromycin on aerobic flora in 14 children treated orally (5 mg/kg/day during 5 to 7 days) quantitative stool cultures were performed using selective media. Enterobacteriaceae (EB), streptococci D (STR D), Staphylococcus aureus, Candida were counted at days 0, 2 and 5 days, and 2 days after treatment. The MIC of each strain was determined for roxithromycin, erythromycin and spiramycin. Ten infants in a nursery had already received antibiotics. A moderate albeit significant (p less than 0.01) decrease was observed for EB, falling from 7.2 log 10 (range 5-9) to 4.9 (range 2-8) per gram of stools, rising to 5.8 after treatment. There was no significant effect for STR D. The MIC of roxithromycin for EB increased from 244 mg/l (range 0.03-512) to 340 (range 0.03-512). For STR. D, it increased from 138 (range 1-1024) to 427 (range 1-1024). The bacteria with low MIC (less than or equal to 64 mg/l for EB and less than or equal to 4 mg/l for STR. D) are Escherichia coli and Streptococcus faecium. The MIC increased for the three macrolides tested.