1969 Volume 17 Issue 6 Pages 979-985
1) The combination of AB-PC with MCI-PC showed excellent bactericidal activity, even at the low concentration (1/20 MIC) which was inactive in both antibiotics alone, against a AB-PC and MCIPC resistant strain of E. coil isolated from a patient. Then in this case, the microbial degradation of AB-PC by this strain was highly prevented in presence of MCI-PC.
2) The enzymatic degradation of AB-PC by extracellar a nd cell-bound PC-ase, obtained from a ABPC resistant strain (No. 39) of Staph. aureus, were at same degree prevented in presence of MCI-PC.
3) The 13-lactam hydrolysis of AB-PC by the crude PC-ase from several pathogenic bacteria we re VOL 17 NO. 6 CHEMOTHERAPY 985 prevented in presence of MCI-PC, but the rates of hydrolysis were not constant among these bacteria used.
4) In the experiment in which the β-actam hydrolysis of AB-PC and PC-G by the PC-ase was determined, when inhibitor (MCI-PC) added to the incubation mixture of substrate (AB-PC or PC-G) with the PC-ase at start, a marked difference was found between the rates of β-lactam hydrolysis of AB-PC and PC-G by the cell-bound PC-ase from Staph. aureus No. 39. Namely, the β-lactam of PC-G was almost hydrolysed with this enzyme (the residual activity; 3%) during incubation, while the β-lactam hydrolysis of AB-PC was remarkably prevented under same condition (the residual activity; 53%).
