A study on the combined use of azithromycin and ofloxacin in refractory complicated urinary tract infection

The efficacy and safety of combined therapy including azithromycin (AZM) and ofloxacin (OFLX) and single therapy with OFLX were compared in patients with rafractory complicated urinary tract infection (UTI) caused by catheters, to assess these methods of treating biofilm infection of the urinary tract. The subjects were patients with UTI who were treated with urethral catheter (including cystostomy). Seven days before the start of administration, the indwelling catheter was changed, and the course was observed without administration of any antimicrobial drug. Patients were registered at the time of this observation. The combined therapy group was given AZM at a single daily dose of 500 mg for 3 days and OFLX at a dose of 200 mg three times a day for 7 days. The single therapy group was given OFLX at a dose of 200 mg three times a day for 7 days. Eight days after the start of administration, the catheter was changed again. Urinary sediment and culture, and clinical tests were performed before and after the administration of drugs, and the surface of the catheter was observed by electron microscopy. Fifteen of the 37 patients were assigned to the combined therapy group and 17 to the single therapy group. The efficacy rates were 66.7% and 47.1% in the respective groups, as evaluated by the attending doctor. According to the criteria of the Japanease UTI committee, overall clinical efficacy was 60.0% in the combined therapy group and 41.2% in the single therapy group. The urine became negative for bacteria in 53.3% of the patients in the combined therapy group and 35.3% of those in the single therapy group. The bacteriological eradication rate was 91.2% in the combined therapy group and 68.8% in the single therapy group. There were no associated side effects or abnormal changes in clinical laboratory test values except for discomfort in the stomach of one patient in the combined therapy group. The inhibitory effect on biofilm formation as determined by electron microscopy tended to be superior in the combined therapy group. These results suggest that combined therapy with AZM and OFLX is an effective method of treating refractory complicated UTI in patients with a catheter.