Susceptibility testing of Enterobacteriaceae within 4.5 h using the ATB system

The use of computerized television morphodensitometry in the study of microbial antagonism

“…Methods of determining microbial antagonistic activity that rely on the use of diffusion into agar [5] can provide only visual information about the actions of biologically active substances (BAS) produced by the microorganisms and do not permit a quantitative evaluation of cell death in the test cultures exposed to the antagonist: the visually observed growth retardation or cessation does not yet give an indication of the actual inhibitory antagonistic effect as no account is taken of bacterial L transformation and reversion. The use of ATB densitometers (Switzerland) to determine the sensitivity of enterobacteria to antibiotics [6] failed to provide data on morphological changes in bacterial populations and, moreover, a comparison with the traditional disk method showed significant differences between the results produced by these two methods.In view of the foregoing, we decided to adapt the method of CTM for quantitative evaluation of microbial antagonism, using model test cultures of Staphylococcus aureus and Escherichia coil …”