The antibacterial activity of oleandomycin and erythromycin—a comparative investigation using microcalorimetry and MIC determination

Abstract

The antibacterial activity of two macrolide antibiotics, oleandomycin and erythromycin, was compared by microdilution MICs and microcalorimetry. The MIC of erythromycin for Staphylococcus aureus strains was one tenth, and for enterococci, one half, that of oleandomycin. The thermograms showed that both antibiotics interfered with bacterial metabolism at concentrations significantly lower than the MIC. Moreover 0.08 to 0.02 μg/ml of either agent altered the thermograms generated by Staphylococcus aureus strain 13665 in an identical way; and this may relate to their similar clinical effectiveness, which does not accord with the difference in MICs. Microcalorimetry proved to be a useful and different way to study the kinetics of antibacterial agents.