yeast vs mould

  • Yeasts: Candida spp, Cryptococcus.
  • Moulds: Aspergillus, Mucor, Fusarium.
  • Dimorphic: Histoplasma, Blastomyces, Coccidioides.

1. azoles (inhibit ergosterol synthesis)

DrugSpectrumKey RoleNotes
FluconazoleYeasts Only (Excl. C. krusei, C. glabrata often resistant)Candidemia (albicans), Thrush, Meningitis (Crypto).Excellent PO bioavailability. NO Mould coverage.
VoriconazoleYeasts + Moulds (Aspergillus)Invasive Aspergillosis (Gold Standard).Visual hallucinations, Fluorosis, Skin Ca.
PosaconazoleYeasts + Moulds + MucorProphylaxis in AML/GVHD.Needs fatty meal (liquid) or tablet absorption.

2. echinocandins (cell wall inhibitors)

  • Agents: Caspofungin, Micafungin, Anidulafungin.
  • Spectrum: Yeasts (Fungicidal) + Aspergillus (Static).
  • Role: First-line for Invasive Candidiasis (covers fluconazole-resistant strains).
  • Safety: Very well tolerated. No renal/hepatic adjustment usually needed. IV only.

3. polyenes (pore formers)

  • Agent: Liposomal Amphotericin B (AmBisome).
  • Spectrum: Broadest (Yeasts, Moulds, Mucor, Protozoa).
  • Role: Severe/Refractory infections, Mucormycosis, Cryptococcal Meningitis (Induction).
  • Toxicity: “Amphoterrible” (Renal tubular acidosis, wasting, rigors). Liposomal formulation reduces nephrotoxicity.