[Study on MIC breakpoint and method of antimicrobial chemotherapy for moderately complicated urinary tract...

We experimentally investigated an efficient administrating method of antimicribials prior to the clinical treatment of complicated urinary tract infection without catheter. An experimental model of moderately complicated urinary tract infection, which can simulate changes in the urinary concentration of antimicrobials by means of previously reported computer control method, was used for the experiment. The following results were obtained. 1. At first, for complicated UTI cases without an indwelling catheter, an investigation was made of the clinical therapy results to determine the upper MIC range of bacteria, including isolated strains, that can be nearly eliminated following treatment, by the administration method. We then estimated the clinical breakpoint. 2. By adjusting the size of the diverticulum in a urinary bladder model, we prepared a model which gave comparatively good agreement between the clinical and experimental breakpoints. 3. The clinical therapy results revealed that by the clinical breakpoint was higher in degree of coverage of the MIC distribution of causative bacteria associated with a higher actual clinical elimination rate and a higher efficacy rate. 4. It was surmised that an efficient administration method for complicated UTI without an indwelling catheter can be established if the urinary bladder model and the following approach are applied: prior to clinical treatment it should be determined what would be high enough to cover 70% of the MIC distribution of the estimated causative bacteria of UTI, and then an administration method which would yield that concentration as the experimental breakpoint should be devised.