How adequate are the new guidelines on clinical evaluation of bacteriological outcome in uncomplicated UTI?

While the Infectious Diseases Society of Americas guidelines for clinical trials of antibiotics have proven valuable for defining inclusion criteria in studies of urinary tract infections, they are far from perfect when it comes to defining outcome of treatment. This was obvious in a trial comparing a beta-lactam antibiotic and a fluoroquinolone for treatment of acute uncomplicated cystitis in women. Depending on how failure was defined in terms of bacterial count and pyuria, failure rates with one and the same regimen varied between 6 and 67% of patients treated with the beta-lactam. Another finding was that pyuria measured with microscopy of urine sediment was a highly unreliable technique. Systematic studies are needed to define the optimal criteria for measuring outcome in these infections.