Related Experiment Video
Updated: Oct 12, 2025
The Galleria mellonella Waxworm Infection Model for Disseminated Candidiasis
Published on: November 17, 2018
Novel Pathogenic Mucorales Identified Using the Silkworm Infection Model
Suresh Panthee1, Hiroshi Hamamoto2, Yayoi Nishiyama2
1Drug Discoveries by Silkworm Models, Faculty of Pharma-Science, Teikyo University, Hachioji, Tokyo 192-0395, Japan.
Abstract:
Mucormycosis, a rare but highly fatal infection, is caused by fungi of the order Mucorales. Due to their ubiquitous nature, reduced susceptibility to antifungals, acid tolerance, and ability to infect immunocompromised patients through rapid dissemination, these fungi have been frequently reported to infect the COVID-19 patients. In order to develop strategies to overcome mucormycosis, it is essential to understand and identify novel Mucorales present in the environment. In this study, we report the identification of four novel pathogenic Mucorales using the silkworm (Bombyx mori) model. The strains' phylogeny was analyzed using the genome sequence of the large subunit ribosomal ribonucleic acid (LSU rRNA) and the internal transcribed spacer (ITS) region, where strains 1-3, 5-3, and S286-1101 claded with Mucor orantomantidis, and strain 827-14 claded with Backusella lamprospora. All the strains had a cold-sensitive phenotype with their inability to grow prominently at 4 °C. Mucor sp. 1-3 and 5-3 were characterized by their filamentous and yeast-like growth under aerobic and anaerobic conditions, respectively. The yeast colonies of Mucor sp. 5-3 had multipolar budding cells often observed with cleaved cell surfaces under a scanning electron microscope. We further found that these strains were able to kill immunocompromised mice suggesting their pathogenicity to mammals. Our study established an invertebrate model-based screening system to identify novel pathogenic Mucorales from the natural environment and provided a clue towards the rapid increase in COVID-19 related mucormycosis.
Insights
Researchers identified four new pathogenic Mucorales fungi using a silkworm model. This discovery aids in understanding and combating mucormycosis, a dangerous infection often linked to COVID-19.
Area of Science:
- Mycology
- Infectious Diseases
- Environmental Microbiology
Background:
- Mucormycosis is a rare, fatal fungal infection caused by Mucorales.
- These fungi are increasingly linked to COVID-19 patients due to their virulence factors.
- Identifying novel Mucorales is crucial for developing effective treatment strategies.
Purpose of the Study:
- To identify novel pathogenic Mucorales from the environment.
- To establish an invertebrate model for screening pathogenic fungi.
- To investigate the pathogenicity of newly identified strains.
Main Methods:
- Utilized the silkworm (Bombyx mori) model for fungal screening.
- Performed phylogenetic analysis using LSU rRNA and ITS gene sequencing.
- Assessed fungal growth under various conditions and pathogenicity in immunocompromised mice.
Main Results:
- Identified four novel pathogenic Mucorales strains.
- Phylogenetic analysis placed strains with Mucor orantomantidis and Backusella lamprospora.
- Demonstrated pathogenicity in silkworms and immunocompromised mice, with a cold-sensitive phenotype.
Conclusions:
- The silkworm model is effective for identifying novel pathogenic Mucorales.
- New strains exhibit pathogenicity and cold-sensitive growth.
- Findings contribute to understanding COVID-19-associated mucormycosis.
