Effect of calcium on in vitro activity of LY146032 against Clostridium difficile

The in vitro MICs of LY146032 against 63 isolates of Clostridium difficile tested in Wilkins-Chalgren broth ranged from 0.5 to greater than 32 micrograms/ml, with MICs of 4 and 8 micrograms/ml for 50 and 90% of the isolates, respectively. However, when the test medium was supplemented with physiologic concentrations of calcium, the MIC for 90% of the isolates was reduced to less than or equal to 0.12 microgram/ml.