Fluconazole treatment of Candida albicans infection in mice: does in vitro susceptibility predict in vivo response?

A series of fluconazole-susceptible and-fluconazole resistant Candida albicans fungal isolates were used to infect mice intravenously. Mice were treated with varying doses of fluconazole beginning one day after infection. For all of the 6 fluconazole-susceptible isolates, fluconazole was highly effective at <0.25 mg/kg of body weight twice daily. By contrast, fluconazole was less effective in at least 6 of 10 fluconazole-resistant isolates and was ineffective at > or = 40 mg/kg twice daily in 4 fluconazole-resistant isolates. Although the correlation is not precise, in vitro susceptibility testing of C. albicans can predict in vivo response to fluconazole.