A Madurella mycetomatis Grain Model in Galleria mellonella Larvae

Area of Science:

• Mycology
• Infectious Diseases
• Medical Entomology

Background:

• Eumycetoma is a chronic subcutaneous infection caused by fungi, primarily Madurella mycetomatis.
• Grain formation is central to mycetoma pathogenesis but poorly understood due to the inability to induce it in vitro.
• Mammalian hosts are currently required for studying mycetoma grain formation.

Purpose of the Study:

• To investigate the potential of greater wax moth (Galleria mellonella) larvae as an invertebrate model for studying Madurella mycetomatis grain formation.
• To assess the feasibility of using G. mellonella larvae for understanding the process of grain formation and evaluating antifungal susceptibility.

Main Methods:

• Three strains of Madurella mycetomatis were used to infect G. mellonella larvae with varying inocula (0.04 mg to 4 mg per larva).
• Larvae were monitored for 10 days post-infection to assess survival and observe grain development.
• Grains formed in larvae were compared to those produced in mammalian hosts.

Main Results:

• G. mellonella larvae survived lower inocula, but higher inocula led to mortality within 10 days.
• Mycetoma grains formed within 4 hours of infection across all tested inocula.
• The morphology of grains formed in G. mellonella larvae was comparable to those found in human and mammalian mycetoma cases.

Conclusions:

• Galleria mellonella larvae provide a viable invertebrate model for inducing Madurella mycetomatis grain formation.
• This G. mellonella model offers a novel platform for future research into mycetoma pathogenesis and antifungal drug efficacy.
• The study establishes a foundation for developing new strategies to combat eumycetoma infections.