ABSTRACTPreviousin vivostudies have reported caspofungin dose escalation to be effective againstCandida glabratawith reduced susceptibility. We hypothesized that higher doses of caspofungin would be effective against invasive candidiasis caused by the more virulent speciesCandida albicans, including isolates resistant to this echinocandin. Immunocompetent mice were inoculated with one of threeC. albicansisolates, including one susceptible and two resistant isolates with differentFKS1hot spot 1 point mutations. Mice received daily caspofungin treatment for 7 days and were then followed off therapy for 2 weeks to assess survival. Kidney tissue and blood were collected, and fungal burden and serum (1→3)-β-d-glucan were measured. Significant differences in virulence were observed among the threeC. albicansisolates, which translated into differences in responses to caspofungin. The most virulent of the resistant isolates studied (isolate 43001; Fks1p F641S) did not respond to caspofungin doses of up to 10 mg/kg of body weight, as there were no differences in survival (survival range, 0 to 12% with treatment), tissue burden, or (1→3)-β-d-glucan concentration compared to those for untreated controls. Higher doses of caspofungin did improve survival against the second resistant isolate (53264; Fks1p S645P) that demonstrated reduced virulence (5 and 10 mg/kg; 80% survival). In contrast, caspofungin doses as low as 1 mg/kg improved survival (85 to 95%) and reduced tissue burden and (1→3)-β-d-glucan concentration against the susceptible isolate (ATCC 90028). These data suggest that caspofungin dose escalation for invasive candidiasis may not be consistently effective against resistantC. albicansisolates, and this may be associated with the virulence of the strain.
TUBERCULOSIS INFECTION MIGHT INCREASE THE RISK OF INVASIVE CANDIDIASIS IN AN IMMUNOCOMPETENT PATIENT
