ESCHERICHIA-COLI DAMAGE BY CERAMIC POWDER SLURRIES

To elucidate the antibacterial mechanisms of the ceramics magnesium ox ide (MgO), calcium oxide (CaO) and zinc oxide (ZnO), damage to bacteri a caused by these powder slurries are studied on the basis of change i n sensitivities to antibiotics, of which the primary inhibitory action s are understood well. Four kinds of antibiotics, penicillin G, chlora mphenicol, nalidixic acid and rifampicin, were used as the selective r eagents. The MgO and CaO powder slurries increased the sensitivities o f Escherichia coli to rifampicin and chloramphenicol. Though the MgO a nd CaO powder slurries have high pH values, changes in the sensitiviti es by the MgO and CaO powder slurries were obviously different from th ose via alkaline treatment. The ZnO powder slurry enhanced the sensiti vity of the E. coli chloramphenicol. This result suggests that the ant ibacterial actions of MgO and CaO powder slurries were different from those of ZnO powder slurry.