In vitro activity of immunosuppressive agents against Cryptococcus neoformans

Area of Science:

• Mycology
• Infectious Diseases
• Pharmacology

Background:

• Cryptococcus neoformans infections are a leading cause of fungal mortality, particularly in immunocompromised individuals such as those with HIV/AIDS or organ transplant recipients.
• Evaluating novel therapeutic strategies is crucial for managing cryptococcosis, an opportunistic mycosis.

Purpose of the Study:

• To assess the in vitro antifungal activity of tacrolimus and cyclosporine A.
• To investigate the synergistic potential of combining these calcineurin inhibitors with established antifungal agents like amphotericin B and fluconazole against Cryptococcus neoformans.

Main Methods:

• Determined Minimum Inhibitory Concentrations (MICs) for 30 clinical isolates of C. neoformans.
• Employed the microdilution method adhering to CLSI M27-A3 guidelines.
• Utilized the checkerboard method to evaluate drug combinations.

Main Results:

• Tacrolimus and cyclosporine A exhibited in vitro activity against C. neoformans isolates.
• Combinations of amphotericin B with cyclosporine A and tacrolimus showed 90% and 30% synergism, respectively.
• Combinations of fluconazole with cyclosporine A and tacrolimus demonstrated 70% and 20% synergism, respectively.

Conclusions:

• Synergistic interactions were observed between calcineurin inhibitors (tacrolimus, cyclosporine A) and antifungal drugs (amphotericin B, fluconazole) against C. neoformans.
• These findings suggest potential for novel therapeutic strategies in treating cryptococcosis.
• Calcineurin inhibitors may play a role in future treatment regimens for this opportunistic fungal infection.