[Significance of the combined treatment with isepamicin and piperacillin in an in vitro model for complicated cystitis operated by automatic simulator apparatus for urinary concentration].

Isepamicin (ISP) and piperacillin (PIPC) were shifted to the urinary concentration by employing an in vitro complicated cystitis model operated by a computer-controlled automatic simulator for urinary concentration, and administrated to bacteria in the urinary bladder model (Pseudomonas aeruginosa: P. aeruginosa, initial cell concentration: 10(7) cfu/ml). In this case, effects by single treatment with ISP or PIPC on cell number curves were examined. Further, significance of the combined treatment with ISP and PIPC were investigated by changing the order of each treatment. And following the results were obtained. 1. In a single treatment with PIPC the cell concentration was minimum (10(4) cfu/ml) at 9th hour after its treatment and thereafter, regrowth to the same level as the initial concentration was observed at 16th hour. 2. In the case of single treatment with ISP, the cell concentration became minimum (10(2) cfu/ml) at 13th hour after the treatment and raised to the same concentration as the initial one at 25th hour. 3. In the combined treatment, the cell concentration was minimum (less than 10(1) cfu/ml) at 26th hour in the case of prior treatment with ISP. Thereafter, regrowth was observed and the cell concentration at 42nd hour reached to the initial cell concentration. 4. In simultaneous treatment with ISP and PIPC, the cell concentration at 24th hour was minimum (10(1) cfu/ml) and reached to the same level as the initial one after regrowth. From these results, it was found that the combined treatment with ISP and PIPC caused more reduction of the cell concentration than either single treatment. Further, regrowth of the cells was suppressed for longer duration.(ABSTRACT TRUNCATED AT 250 WORDS)