THE POSTANTIBIOTIC EFFECT OF IMIPENEM - RELATIONSHIP WITH DRUG CONCENTRATION, DURATION OF EXPOSURE, AND MIC

The postantibiotic effect (PAE) of imipenem against Escherichia coli w as measured at a wide variety of drug concentrations and times of expo sure, We observed that the area under the concentration-time curve of drug exposure (AUG), the product of time of exposure and concentration of drug, is a much better predictor of the duration of the PAE than e ither parameter alone, We also measured the PAE of imipenem against st rains of gram-positive and gram-negative bacteria for which MICs varie d widely, The E-50, the AUC required to produce 50% of the maximum PAE , is correlated with the MIC and is independent of species, This may e xplain why the duration of the PAE differs for bacteria of the same sp ecies for which MICs are different.