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Consider alternative antibiotic in children prescribed trimethoprim recently, GPs advised

GPs should consider an alternative antibiotic to trimethoprim in children with a recurrent urinary tract infection who have received the drug in the previous three months, say UK researchers.

The study

Data on Scottish patients under 16 years of age with urine samples that showed pure E.coli growth of equal to or more than 104 colony-forming units/ml, and where trimethoprim resistance was analysed. These data were linked to prescribing data for trimethoprim. 1,855 urine samples from 1,373 children were included in the analysis.

The findings

Some 26.6% of included E.coli isolates from urine samples were trimethoprim resistant, rising from 19% in 2004 to 33.3% in 2009. Children who had previously been prescribed trimethoprim were more likely to have resistant E.coli than those who had not. Those prescribed it within the last two weeks were almost five times more likely to be resistant, compared with those not prescribed it. This remained the case when extended to children prescribed within the last 28 days, but dropped to just over three times more likely when increased to a prescription within the last 84 days. The interaction was not significant for children prescribed trimethoprim from 85 to 168 days, 189 to 365 days and over 365 days.

What does it mean for GPs?

The Dundee-based authors felt the results ‘suggest that an alternative antibiotic should be considered in cases of childhood UTI if trimethoprim has been prescribed in the previous three months.’ They advised that clinicians ‘must be prudent prescribers and ensure appropriateness of antibiotic choice and length of treatment when bacterial infections is proven or highly likely.’

BJGP 2013, available online 25 March