NEW YORK (Reuters Health) – In children with urinary tract infection (UTI), trimethoprim (TMP) can be used as an alternative to trimethoprim/sulfamethoxazole (TMP/SMX) without compromising antibacterial activity, according to a study in the July issue of The Journal of Urology, available online now.

It might also be safer, the researchers say.

The study showed that adding SMX to TMP does not increase the in vitro antibacterial activity in children with UTI caused by Escherichia coli — the bacteria that cause more than 80% of UTIs in children. Klebsiella species were equally susceptible to TMP.

“Routine, frequent use of TMP/SMX for pediatric UTI should be carefully reevaluated,” concludes a US multicenter team led by Dr. Hiep T. Nguyen of Children’s Hospital Boston.

The study involved 1,298 children, aged 1 month to 12 years, with culture confirmed UTI with greater than 11359,000 cfu/mL E. coli from 4 US cities (Boston, Detroit, Los Angeles and Cincinnati).

In vitro susceptibility of E. coli to TMP was comparable to that of TMP/SMX (70.0% for both) and significantly higher than that of SMX alone (56.9%), the study team reports. This suggests that TMP is likely the principle component of TMP/SMX that provides antimicrobial activity,” they note.