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


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.
McNulty
C A M
CA
Health Protection Agency Primary Care Unit, Microbiology Department, Gloucestershire Royal Hospital, Great Western Road, Gloucester, and Microbiology Department, Norfolk and Norwich University Hospital NHS Trust, Norwich, UK. cliodna.mcnulty@hpa.org.uk
Richards
J
J
Livermore
D M
DM
Little
P
P
Charlett
A
A
Freeman
E
E
Harvey
I
I
Thomas
M
M
D000208:Acute Disease; D000328:Adult; D000368:Aged; D000890:Anti-Infective Agents / Q000494:pharmacology / Q000627:therapeutic use*; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000188:drug therapy* / Q000382:microbiology*; D005260:Female; D006801:Humans; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011320:Primary Health Care; D011446:Prospective Studies; D016896:Treatment Outcome; D014295:Trimethoprim / Q000494:pharmacology / Q000627:therapeutic use*; D014296:Trimethoprim Resistance; D014552:Urinary Tract Infections / Q000188:drug therapy* / Q000382:microbiology*
D000890:Anti-Infective Agents; D014295:Trimethoprim