Variation in Antibiotic Susceptibility of Uropathogens by Age Among Ambulatory Pediatric Patients 1

We compared uropathogen antibiotic susceptibility across age groups of ambulatory pediatric patients. For Escherichia coli (n = 5,099) and other Gram-negative rods (n = 626), significant differences (p < 0.05) existed across age groups for ampicillin, cefazolin, and trimethoprim/sulfamethoxazole susceptibility. In E. coli, differences in trimethoprim/sulfamethoxazole susceptibility varied from 79% in children under 2 to 88% in ages 16–18 (p < 0.001), while ampicillin susceptibility varied from 30% in children under 2 to 53% in ages 2–5 (p = 0.015). Uropathogen susceptibility to common urinary anti-infectives may be lower in the youngest children. Further investigation into these differences is needed to facilitate appropriate and prudent treatment of urinary tract infections.