Correlation of serum cefotaxime levels by HPLC with serum bacteriostatic and bactericidal levels

The clinical response to treatment by cefotaxime and amikacin in febrile, neutropenic, leukaemic patients has been disappointing in one large series of patients. To investigate whether this could be due to paradoxical decreased killing at high concentrations of cefotaxime, serum cefotaxime levels measured by high performance liquid chromatography were compared with serum bacteriostatic and bactericidal titres, measured microbiologically. There was excellent correlation between the biochemical HPLC method and the bacteriostatic/bactericidal microbiological method, with no evidence of paradox.