New time-effect curve (TEC) of antibiotics to compare antibacterial activity is proposed. It consists of a comparison of MIC with drug concentration in blood. A drug concentration at a certain time is obtained from time-concentration curve (TCC), and the expecting effect of antibacterial activity is obtained from MIC-cumulative percent of strain inhibited curves.
Antibiotics such as CCL or CPDX-PR show different TECs against each bacteria. Different TECs were obtained using only MIC when comparing with IPM/CS, CPZ and CFS. In the case of DKB, the speed of dropping injections was examined. Against E. coli, different shape of TEC was obtained for each dropping speed, but against P. aeruginosa and Staphylococcus, almost the same TECs were obtained. The dropping speed might not be so important in the latters.