title: Analysis of cephalosporin-induced changes in the volume distribution of Escherichia coli cultures by an electronic counter-channelanalyser.
abstract: The demonstration of morphological alterations of the bacterial cell together with bactericidal kinetics are of value for the description of the antibacterial activity of beta-lactam antibiotics. One of the indicators of antibiotic effect on bacterial morphology is the change in bacterial cell volume. This can be demonstrated graphically and numerically by means of electronic cell counting and volume distribution analysis using the Coulter Counter-Channelanalyser system connected to a computer. After registration of the distribution of the relative volume of the Escherichia coli population, the mean cell volume was calculated. The latter parameter increased more than 6 fold with increasing cefotaxim-exposure times. The onset of the delayed (2 h after cefotaxim administration) bacteriolytic effect was reorganized by the appearance of small cell breakdown particles and quantified by counting. In order to demonstrate the therapeutic process graphically the distribution curves were transformed to a common scale. Since a complete storage of the data per sample is performed normally within one minute, the Coulter Counter-Channelanalyser technique can be carried out simultaneously with the bactericidal kinetic experiment. The data demonstrate the speed and intensity of the morphological cell alterations induced by the beta-lactam antibiotic.
mesh_terms: D001431:Bacteriological Techniques / Q000295:instrumentation; D001433:Bacteriolysis; D002439:Cefotaxime / Q000494:pharmacology*; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects*
chemical_list: D002439:Cefotaxime