Recovery period after exposure of Staphylococcus aureus to sub-inhibitory and bactericidal concentrations of rifampicin: clinical implications.

The effects of rifampicin, at subinhibitory and bactericidal concentrations, were examined in the presence of and after the removal of the drug. After exposure to subinhibitory concentrations as low as one-tenth of the MIC an extended recovery period was observed. Incubation of exponential or stationary phase cultures for 30 min or 4 h with a bactericidal concentration also caused a significantly prolonged recovery period.