Recurrent Fusarium keratomycosis: a light and electron microscopic study
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Abstract:
Corneal buttons infected with Fusarium solani, were removed during penetrating keratoplasty, and studied by light and electron microscopy. Histologically, it appeared that the hyphae penetrated Descement 's membrane and the posterior stroma from the anterior chamber. Their cell wall, plasmalemma, and cytoplasm were preserved indicating that the fungi might be still active despite antifungal therapy, which may not be effective once the fungus penetrates Descemet's membrane. The other interesting feature was the total lack of phagocytic activity of macrophages on adjacent fungal hyphae indicating possible suppression of host defense responses in this cornea. Patients with fungal keratitis should be treated with antifungal drugs at an early stage, and therapeutic penetrating keratoplasty appears to be most effective, if performed before the fungus penetrates the barrier of Descemet's membrane.
Insights
Fusarium solani fungal keratitis can penetrate Descemet's membrane, hindering antifungal treatment. Early intervention with antifungal drugs and penetrating keratoplasty before membrane penetration is crucial for effective treatment.
Area of Science:
- Ophthalmology
- Mycology
- Microbiology
Background:
- Fungal keratitis is a serious eye infection.
- Fusarium solani is a common cause of fungal keratitis.
- Penetrating keratoplasty is a surgical option for severe cases.
Observation:
- Corneal buttons from patients with Fusarium solani keratitis were examined using light and electron microscopy.
- Fungal hyphae were observed penetrating Descemet's membrane and posterior stroma.
- Macrophages showed no phagocytic activity against fungal hyphae.
Findings:
- Fungal hyphae remained morphologically intact, suggesting potential viability despite antifungal therapy.
- Penetration of Descemet's membrane by Fusarium solani may render antifungal therapy ineffective.
- Host immune response, specifically macrophage activity, appeared suppressed in affected corneas.
Implications:
- Early diagnosis and treatment of fungal keratitis with antifungal drugs are essential.
- Therapeutic penetrating keratoplasty is most effective when performed before Descemet's membrane is breached.
- Understanding fungal invasion mechanisms and host immune evasion is critical for developing novel therapeutic strategies.