Differential activity of triazoles in two-drug combinations with the echinocandin caspofungin against Aspergillus fumigatus

J Antimicrob Chemother. 2003 Jun;51(6):1423-5. doi: 10.1093/jac/dkg242. Epub 2003 Apr 25.

Abstract

Objectives: We investigated the in vitro activity of various triazoles in two-drug combinations with the echinocandin caspofungin against clinical isolates of Aspergillus fumigatus.

Method: Conidial suspensions were prepared from 20 clinical isolates of A. fumigatus highly susceptible to itraconazole, voriconazole, posaconazole and ravuconazole (MIC-0 range 0.125-1 mg/L), and caspofungin (MIC-0 range 32-64 mg/L). The in vitro susceptibility of A. fumigatus to two-drug combinations of itraconazole, voriconazole, posaconazole and ravuconazole with caspofungin was evaluated by the fractional inhibitory concentration index (FICI) method.

Results: Two-drug combinations of caspofungin with itraconazole (FICI = 0.49 +/- 0.04) or posaconazole (FICI = 0.32 +/- 0.09) provided synergic interaction. On the other hand, ravuconazole (FICI = 0.61 +/- 0.31) and voriconazole (FICI = 1.61 +/- 0.42) in combination with caspofungin showed no interaction against A. fumigatus.

Conclusions: Our data show that the in vitro antifungal efficacies of combinations of members from two different classes are not always similar and hence are not predictable.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aspergillus fumigatus / drug effects*
  • Aspergillus fumigatus / growth & development
  • Caspofungin
  • Drug Interactions / physiology
  • Drug Therapy, Combination
  • Echinocandins
  • Humans
  • Lipopeptides
  • Microbial Sensitivity Tests / methods
  • Peptides / administration & dosage*
  • Peptides, Cyclic*
  • Triazoles / administration & dosage*

Substances

  • Echinocandins
  • Lipopeptides
  • Peptides
  • Peptides, Cyclic
  • Triazoles
  • Caspofungin