Caspofungin resistance in Candida albicans: correlating clinical outcome with laboratory susceptibility testing of three isogenic isolates serially obtained from a patient with progressive Candida esophagitis.

A patient with azole-refractory thrush-esophagitis responded initially to caspofungin, but the treatment eventually failed. In a murine model, caspofungin was effective against two early isolates for which the MICs of caspofungin were low, but it was less effective against a late isolate for which the MIC of caspofungin was greater. We concluded that there is a correlation between in vivo failure and rising in vitro caspofungin MICs.