The significance of bacterial kinetic examinations for an adequate dosage of antibiotic

Abstract

The sources of error in the measurement of bacterial growth curves in closed systems are demonstrated by opacity. In investigations of bactericidal kinetics, it is necessary to observe the viable count by optical density because of the lesser susceptibility. Results obtained in this way cannot simply be applied to the chemotherapy of bacterial infections. Some of the findings may be important in view of our knowledge about the mechanism of antibacterial action, e. g. the latent period is important and indicates the speed of bactericidal action. In our experiments with eight cephalosporins and Klebsiella pneumoniae, the latent periods varied from 19.8 min for cefazolin to 102.8 min for cefuroxime. The inoculum dependence of antibacterial activity which was discovered in these investigations is also significant for determining an optimal dose because the bacteria should be reduced to a minimum by an initial high dose of antibiotic.