, et al
Predictors of antimicrobial resistance among pathogens causing urinary tract infection in children
J Pediatr
; doi:

Investigators at multiple US institutions sought to determine which children with urinary tract infections (UTI) were likely to have pathogens resistant to narrow-spectrum antibiotics. Children who were 2–71 months of age and enrolled in the Randomized Intervention for Children with Vesicoureteral Reflux (RIVUR) or Careful Urinary Tract Infection Evaluation (CUTIE) studies were included (see AAP Grand Rounds, November 2015;34[5]:51). The RIVUR study included children with a first or second febrile or symptomatic UTI and grades I–IV vesicoureteral reflux (VUR), while the CUTIE study included children with a first or second UTI without VUR. None of the study children were receiving antimicrobial prophylaxis for VUR at the time of diagnosis of the index UTI.

Resistance patterns for uropathogens were reported according to each laboratory’s protocol. Pathogens were considered resistant if they demonstrated either intermediate or full resistance. Narrow-spectrum antibiotics included amoxicillin, trimethoprim-sulfamethoxazole (TMP-sulfa), nitrofurantoin, and first generation cephalosporins. Participant data collected included age, sex, race, ethnicity, presence of bladder and bowel dysfunction (BBD [lower urinary tract symptoms associated with constipation and/or encopresis]), use of antibiotics in the preceding 6 months for infections other than UTIs, and type of index UTI (febrile vs afebrile). Logistic regression models were used to test the independent association between participant demographics or clinical characteristics and resistance to narrow-spectrum antibiotics. The investigators separately examined whether the presence or grade of VUR was associated with resistance to narrow-spectrum antibiotics.

Of 769 children studied, 91% were female, 78% were white, and 49% were 2–11 months of age. Overall, 91% had index UTIs caused by Escherichia coli. Sensitivity to amoxicillin was low: 55% for E coli and 61% for other bacteria. E coli exhibited high sensitivity to nitrofurantoin and first generation cephalosporins (99% and 93%, respectively), but only 81% of E coli were sensitive to TMP-sulfa. On the other hand, other pathogens demonstrated lower sensitivity to nitrofurantoin (40%) than to first generation cephalosporins (72%) and TMP-sulfa (98%). Sensitivity to second and third generation cephalosporins was >90% for all bacteria and considerably higher than sensitivity to amoxicillin-clavulanate.

There were significantly increased odds of resistance to narrowspectrum antibiotics in uncircumcised males compared to females (OR = 3.1) as well as in children with BBD compared to those without BBD (OR = 2.2). Hispanic children were significantly more likely to have UTIs caused by bacteria resistant to TMP-sulfa than non-Hispanic children (OR = 2.5). Those with higher grade VUR had more resistance to nitrofurantoin. Exposure to 1 (but not ≥2) antibiotic course in the preceding 6 months was associated with an increased odds of resistance to narrow-spectrum antibiotics.

The investigators conclude that uncircumcised males, children with BBD, Hispanic children, and children who had received antimicrobials in the past 6 months had higher odds of a UTI with resistant uropathogens....

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