Double antimicrobial prophylaxis in girls with breakthrough urinary tract infections.

OBJECTIVE

Some girls receiving antimicrobial prophylaxis for recurrent urinary tract infections (UTIs) experience breakthrough infections. The clinical characteristics of girls experiencing a breakthrough UTI and the efficacy of an antimicrobial combination was studied.

METHODS

Girls were managed by frequent timed voiding, anticholinergic medication for bladder instability, and double antimicrobial prophylaxis consisting of nitrofurantoin (NFN) 2 mg/kg every morning and trimethoprim/sulfamethoxazole (TMP/SMZ) 2/10 mg/kg at bedtime.

RESULTS

A total of 31 girls had experienced sixty-four UTIs during three hundred sixty-seven months (17.4 UTIs/100 patient-months) while receiving TMP/SMZ and/or NFN as single-drug prophylaxis. Of the girls, 21 (68%) had reflux, 15 (49%) had detrusor instability/voiding dysfunction, 8 (26%) had both reflux and voiding dysfunction, and 3 (10%) had neither voiding dysfunction nor reflux. While receiving double antimicrobial prophylaxis, 8 girls (26%) experienced a UTI and only 3 (10%) showed a UTI resistant to both TMP/SMZ and NFN. There were only sixteen breakthrough UTIs during four hundred thirty-nine months of double prophylaxis (3.6 UTIs/100 patient-months) (P < 0.001).

CONCLUSIONS

Girls with breakthrough UTIs usually have voiding dysfunction and/or reflux, and in these girls double antimicrobial prophylaxis and attention to voiding dynamics were effective in preventing further UTIs.