Echinocandins are not active against which fungal pathogen?

• A. Histoplasma
• B. Cryptococcus
• C. Candida albicans
• D. Aspergillus fumigatus

Answer: (B)

Echinocandins work by inhibiting synthesis of 1,3-β-D-glucan, a major component of the fungal cell wall in many fungi. This makes them highly effective against Candida species and they have activity against Aspergillus to some extent. However, Cryptococcus neoformans has relatively low 1,3-β-D-glucan content in its cell wall and relies more on its capsule and other wall components, so blocking glucan synthesis doesn’t disrupt its structure effectively. That’s why echinocandins are not active against cryptococcal infections. Candida albicans, with abundant glucan in its wall, is susceptible, and Aspergillus fumigatus can be affected by these drugs, though treatment choices for Aspergillus are nuanced.