The Escherichia coli O25b/sequence type 131 (ST131) clone can be used to predict treatment failure in patients with urinary tract infections, say researchers. Can et al. studied 294 patients who had acute urinary cystitis with isolation of E. coli in their urine cultures. They followed patients for clinical cure after 10 days of treatment and found that detection of the E. coli O25:ST131 clone by PCR was a significant risk factor for treatment failure.