Poor compliance may be an issue with long-term prophylaxis and may represent patient or parent practice.9One study found that in children taking low-dose trimethoprim, 97% of the parents reported giving antibiotics on daily basis, but in 31% of subjects, trimethoprim was not detectable in the urine.6Risk of prophylaxis includes nausea, vomiting, and rash in 8% to 10% of patients; development of resistant organisms; and change in indigenous microflora.6 One study of resistance found that children who received antibiotics for more than 4 weeks in the previous 6 months were more likely to have resistant Escherichia coli isolates than children who had not received prolonged antibiotic treatment (odds ratio [OR]=13.9; 95% CI, 8.2–23.5). Children with abnormalities of the genitourinary tract were approximately 4 times more likely to have resistant isolates of E coli than children without abnormalities of the genitourinary tract (OR=3.9; 95% CI, 2.7–5.7).11
Recommendations from others
The American Academy of Pediatrics, American Urological Association, and the Swedish Medical Research Council guidelines recommend prophylaxis for children with reflux ( Table ), but they all acknowledge that the recommendations are not supported by well-designed randomized controlled trials.1-3 No guidelines are available for children with neurogenic bladder and recurrent urinary tract infections.7
TABLE
Oral antibiotics for prophylaxis of urinary tract infections in children
| Antimicrobial | Prophylaxis dosage |
|---|---|
| Trimethoprim/sulfamethoxazole (TMP/SMX) (Bactrim, Septra) | 2 mg of TMP, 10 mg of SMX per kg as single bedtime or 5 mg of TMP, 25 mg of SMX per kg twice per week |
| Nitrofurantoin (Macrodantin) | 1–2 mg/kg as single daily dose |
| Cephalexin (Keflex) | 10 mg/kg as single daily dose |
| Amoxicillin | 10 mg/kg as single daily dose |
| Sulfisoxazole (Gantrisin Pedatric) | 10–20 mg/kg divided every 12h |
| Modified with permission from AAP 1999;3Allen et al1999.10 | |
Clinical commentary:
UTI prevention most successful when the child exhibits efficiency of voiding
William R Strand MD
Division of Pediatric Urology, University of Texas Southwestern Medical Center, Dallas
The relative benefit of antibiotic prophylaxis in prevention of UTI in children with anatomic abnormalities like vesicoureteral reflux could best be determined if all other risk factors for UTI were controlled. Unfortunately, these other factors are often more significant in promoting UTI than is reflux, and they are also more difficult to quantify. Voiding dysfunction and constipation can both increase bladder storage pressures and postvoid residual urine volumes, and as such greatly predispose children for UTI. Furthermore, a distended colon provides an abundant reservoir of pathogens with an array of uropathogenic virulence factors.
Published reports have failed to detect significant benefit for antibiotic prophylaxis in part because the children studied possess varying risks for UTI. Prevention of UTI is most successful when the child exhibits efficiency of voiding and elimination. Clinical practice in pediatric urology advocates use of antibiotic prophylaxis in children with vesicoureteral reflux. Reflux should be suspected in children with hydroureter, multicystic renal dysplasia, ureteral duplication, and ureterocele.