Evaluation of the resistance induction in enteric flora in children caused by oral ampicillin plus sulbactam.

To evaluate the effect on bacterial resistance of a -lactamase inhibitor, resistance patterns of predominant bacteria in enteric flora were evaluated before and after a 7-day course of oral ampicillin (100 mg/kg/days, qid, in 16 patients) and ampicillin‐sulbactam (50 mg/kg/day of ampicillin, bd, in 32 patients) therapy. Ampicillin and ampicillin‐sulbactam MICs for Escherichia coli, the predominant bacteria in all cases, and resistance rates of E. coli species to both antibiotics were 51.20 ± 13.80 mg/L, 87.5% and 4.84 ± 2.11 mg/L, 21% before the treatment respectively. Post-treatment MICs and resistance rates were 106.51 ± 14.05 mg/L, 100% and 15.89 ± 5.76 mg/L, 37.5% respectively, indicating a significant increase in MICs of both antibiotics (P < 0.05), being more prominent in the case of ampicillin‐sulbactam (about fourfold). We concluded that oral ampicillin‐sulbactam could also decrease the susceptibility of the enteric flora to ampicillin.