FIG. 2.
Killing of S. typhi by ceftazidime and subsequent release of LPS at various concentrations of the antibiotic. (A) The number of viable bacteria was corrected for ongoing multiplication of the inoculum. For each curve the mean survival time of the bacteria was calculated as the first statistical moment. This calculation is based on the AUC extrapolated to infinity (see Materials and Methods section). The mean survival time is a measure of TLPSV. For example, the effect at 16 μg/ml corresponds to a TLPSV value of 0.58 ± 0.09 h. (B) The amount of labelled LPS bound in the membrane of viable as well as nonviable bacteria was calculated by subtracting the actual amount of LPS released at each time point from the maximum amount of label released at the highest concentration. The first statistical moment of these curves was calculated, and this resulted in a value for TLPSV/NV. For example, the effect at 16 μg/ml corresponds to a TLPSV/NV value of 1.77 ± 0.23 h.