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The Pathogenicity of Stachybotrys chartarum.
Eri Ochiai1, Katsuhiko Kamei, Kenzo Hiroshima
1Graduate School of Science and Technology, Chiba University, Matsudo-city, Chiba 271-8510, Japan.
Summary
Stachybotrys chartarum conidia resist immune cells but are cleared by mouse lungs. However, fungal toxins cause lung inflammation and damage, suggesting inhalation risks for humans, especially with repeated exposure.
Area of Science:
- Mycology
- Immunology
- Toxicology
Background:
- Stachybotrys chartarum, a common indoor mold, was historically considered non-pathogenic.
- Emerging evidence suggests potential pathogenicity, particularly concerning infant pulmonary hemorrhage.
Purpose of the Study:
- To investigate the pathogenicity of Stachybotrys chartarum conidia.
- To examine the interaction between S. chartarum and host immune cells (macrophages, PMNs).
- To assess lung histopathology following fungal exposure in a mouse model.
Main Methods:
- In vitro studies using alveolar macrophages and polymorphonuclear leukocytes (PMNs).
- Intratracheal injection of S. chartarum conidia into mice.
- Histopathological analysis of lung tissues from exposed mice.
- Cytotoxicity assays of fungal lavage fluid.
Main Results:
- S. chartarum conidia demonstrated resistance to macrophage phagocytosis, killing, and germination inhibition.
- Conidia were cleared from mouse lungs after intratracheal injection.
- Fungal lavage fluid exhibited cytotoxicity against macrophages and PMNs.
- Repeated intratracheal injections induced significant PMN and eosinophilic infiltration in mouse lungs.
Conclusions:
- S. chartarum conidia possess mechanisms to evade innate immune responses.
- Fungal-associated toxins contribute to lung inflammation and damage.
- Inhalation of S. chartarum may pose a significant risk of lung injury in humans, especially with chronic exposure.