Abstract
We report our experience with a 9-month-old infant treated with intravenous polymyxin B for multidrug-resistant Klebsiella pneumoniae bacteremia. Serial blood samples were obtained at steady state and serum drug concentrations were determined using a validated liquid chromatography-mass spectrometry method. The elimination half-lives of polymyxin B1 and isoleucine-polymyxin B1 were found to be 3.1 and 4.7 hours, respectively.