Résumé
Prophylactic antibiotics are commonly used for prevention of urinary tract infections [UTIs] in children. It was postulated that the organisms and resistance patterns of breakthrough infections would differ with the choice of antimicrobial prophylaxis. This was a retrospective descriptive study of all breakthroughs UTI from 2000 to 2006 in children over 1 month of age discharged from a referral children's hospital in Tehran, Iran on continuous antibiotic prophylaxis for UTIs. Fifty-seven children discharged on prophylaxis had breakthrough UTIs of which 32 [56%] had a previously diagnosed urinary tract anomaly. Escherichia coli was responsible for the majority of infections irrespective of choice of prophylaxis. Thirty-three of 56 breakthrough UTIs [59%] were with organisms that were resistant to the prophylactic antibiotic. There was an increased incidence of resistance to prophylaxis in children on cefixime [16 of 22; 78%] when compared with children on cephalexin [7 of 19; 37%; p = 0.02] and a trend toward increased resistance when compared with children on trimethoprim-sulfamethoxasole [3 of 8; 37%] [p = 0.10]. In conclusion, the resistance pattern of organisms causing breakthrough UTIs varies with the choice of prophylaxis which should be taken into consideration in choosing empiric therapy for such infections