Uncomplicated urinary tract infections. Bacterial findings and efficacy of empirical antibacterial treatment

OBJECTIVE: To assess bacterial aetiology, antimicrobial susceptibility and efficacy of empirical treatment in uncomplicated urinary tract infections and to evaluate the dipstick as a diagnostic tool. DESIGN: Prospective study. SETTING: Clinical microbiology laboratory and 17 general practice clinics in Telemark County, Norway. SUBJECTS: A total of 184 female patients between 15 and 65 years of age with symptoms of uncomplicated urinary tract infection. MAIN OUTCOME MEASURES: Results from dipstick testing (leucocyte esterase and nitrite), bacterial culture, susceptibility patterns and efficacy of empirical antibacterial therapy on symptoms. RESULTS: Significant bacteruria was detected in 140 (76%) of the 184 urines. The leukocyte esterase test was of little help in predicting culture-positive UTI. A positive nitrite test accurately predicted culture-positivity, while a negative result was ambiguous. The most common bacterium, E. coli, was found in 112 (80%) of the 140 positive urines and was predominantly sensitive to ciprofloxacin (100%), mecillinam (94%), nitrofurantoin (97%), trimethoprim (88%), and sulphonamide (81%), and to a lesser extent to ampicillin (72%). In 18 patients the causative bacterium was resistant to the therapeutic agent used; 7 of these returned to their GP with persisting symptoms while in 11 symptoms resolved without further treatment. CONCLUSION: The study confirms E. coli as the predominant cause of uncomplicated UTI. Since in the majority of cases the bacterium found was susceptible to the locally preferred antimicrobials and the patients' symptoms were cured, empiric therapy is found to be an effective practice in the study area and, by inference, in others with similar antimicrobial susceptibility patterns.