Bactericidal activity of continuously changing cefotaxime concentrations in human blood

Activity of cefotaxime against Escherichia coli and Klebsiella pneumoniae was investigated in a model producing in-vitro simulation of pharmacokinetic parameters. Bacteria were suspended in fresh human blood in which the cefotaxime concentration rose slowly from zero to a mean peak of 9.62 mg/l (+/- 1.95) at a mean of 2.8 h (+/- 0.44) and dropped to below detection level of less than 1 mg/l at 12 h. Under these conditions cefotaxime was rapidly bactericidal. Only one out of the six strains tested had recovered from the toxic effect of cefotaxime after 24 h.