Medical relevance of low concentrations of antibiotics.

Low concentrations of antibiotics or sub-minimum inhibitory concentrations (sub-MIC) have been shown in vitro to alter the ultrastructure and antigenicity of bacteria, their adherence to epithelial cells, their synthesis and excretion of pathogenic enzymes and their rate of growth. The same effects have been detected when low concentrations of antibiotic act on bacteria in vivo. Animal experiments as well as clinical investigations have demonstrated therapeutic results with sub-MICs at the site of infection.