Clinical relevance of laboratory-reported antibiotic resistance in acute uncomplicated urinary tract infection in primary care

J Antimicrob Chemother. 2006 Nov;58(5):1000-8. doi: 10.1093/jac/dkl368. Epub 2006 Sep 23.


Objectives: To determine whether patients with an uncomplicated community-acquired urinary tract infection (UTI) and an isolate resistant to trimethoprim had worse clinical outcomes following empirical treatment with trimethoprim 200 mg twice daily for 3 days than did those with a susceptible isolate.

Patients and methods: This was a prospective cohort study of clinical outcome. We enrolled 497 women (>or=18-70 years) presenting to general practitioner surgeries in Norwich and Gloucester with at least two symptoms of acute (<7 days) uncomplicated UTI. Significant bacteriuria was defined as >or=10(4) cfu/mL from a mid-stream urine (MSU).

Results: Of enrolled patients 75% (334/448) had significant bacteriuria, and trimethoprim resistance was present in 13.9% (44/317) of isolates. Patients with resistant isolates had a longer median time to symptom resolution (7 versus 4 days, P=0.0002), greater reconsultation to the practice (39% versus 6% in first week, P<0.0001), more subsequent antibiotics (36% versus 4% in first week, P<0.0001) and higher rates of significant bacteriuria at 1 month (42% versus 20% with susceptible isolate, P=0.04). Half of patients reconsulting in the first week had a resistant organism.

Conclusions: Patients with uncomplicated UTI caused by trimethoprim-resistant organisms had significantly worse clinical outcomes than those with trimethoprim-susceptible organisms. Nevertheless, trimethoprim resistance was rarer than predicted from routine laboratory submissions and we calculate that 23 women require microbiological investigation to prevent one reconsultation arising from resistance-based treatment failure. We therefore suggest empirical antibiotic treatment in acute, uncomplicated UTIs. If patients reconsult in the first week, we suggest a change of antibiotic treatment with urine culture and susceptibility testing then done. More generally, laboratory resources should concentrate on resistance surveillance to inform empirical antibiotic choice.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Adult
  • Aged
  • Anti-Infective Agents / pharmacology
  • Anti-Infective Agents / therapeutic use*
  • Cohort Studies
  • Community-Acquired Infections / drug therapy*
  • Community-Acquired Infections / microbiology*
  • Female
  • Humans
  • Microbial Sensitivity Tests
  • Middle Aged
  • Primary Health Care*
  • Prospective Studies
  • Treatment Outcome
  • Trimethoprim / pharmacology
  • Trimethoprim / therapeutic use*
  • Trimethoprim Resistance*
  • Urinary Tract Infections / drug therapy*
  • Urinary Tract Infections / microbiology*


  • Anti-Infective Agents
  • Trimethoprim