Human fusariosis

Fusarium species frequently implicated in human infections include F. solani, F. oxysporum and F. moniliforme. Among immunocompetent patients, tissue breakdown (as caused by trauma, severe burns or foreign body) is the risk factor for fusariosis. Infections include keratitis, onychomycosis and occasionally peritonitis and cellulitis. Treatment is usually successful and requires removal of the foreign body as well as antifungal therapy. Among immunocompromised patients, mainly patients with haematological malignancies, Fusarium spp. are the second most common pathogenic mould. Risk factors for disseminated fusariosis include severe immunosuppression (neutropenia, lymphopenia, graft-versus-host disease, corticosteroids), colonisation, tissue damage, and receipt of a graft from an HLA-mismatched or unrelated donor. Clinical presentation includes refractory fever (> 90%), skin lesions and sino-pulmonary infections ( approximately 75%). Type of skin lesions includes ecthyma-like, target, and multiple subcutaneous nodules. Skin lesions lead to diagnosis in > 50% of patients and precede fungemia by approximately 5 days. In contrast to disseminated aspergillosis, disseminated fusariosis can be diagnosed by blood cultures in 40% of patients. Histopathology reveals hyaline acute-branching septate hyphae similar to those found in aspergillosis. Mortality from fusarial infections in immunocompromised patients ranges from 50% to 80%. Host immune status is the single most important factor predicting outcome. Persistent neutropenia and corticosteroid therapy significantly affect survival. Optimal treatment has not been established. Anecdotal successes have been reported with various agents (high-dose amphotericin B, lipid-based amphotericin B formulations, itraconazole, voriconazole) and with cytokine-stimulated granulocyte transfusions. Preventing fusariosis relies on detection and treatment of cutaneous damage prior to commencing immunosuppression and decreasing environmental exposure to Fusaria (via air and water).