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Clinical features of human infection with Scedosporium inflatum
G M Wood1, J G McCormack, D B Muir
1University of Queensland Department of Medicine, Mater Misericordiae Hospital, South Brisbane, Australia.
Abstract:
We report on 17 Australian cases of human infection or colonization with Scedosporium inflatum. The spectrum of clinical manifestations was similar to that in infection caused by Scedosporium apiospermum. The patients were classified into three groups. Four immunocompetent patients who presented with localized infections of a joint, nail bed, eye, or sphenoidal sinus made up the first group. Our first case, in a boy with posttraumatic septic arthritis, responded to surgical drainage with amphotericin B followed by treatment with itraconazole. The other three cases were cured by surgery alone. The second group consisted of five immunocompromised patients who presented with disseminated infections in a variety of sites. Four of these patients did not respond to antifungal therapy and died. The fifth apparently responded to antifungal drugs after correction of his neutropenia. The third group included eight patients with asymptomatic colonization in the external ear (five cases) or respiratory secretions (three cases). The nine isolates of S. inflatum tested by both disk and agar dilution methods were resistant to antifungal drugs. In our first case, which responded clinically to itraconazole, the MIC of this drug for the fungal isolate was 25 micrograms/mL. Thus S. inflatum can cause a broad spectrum of human infections whose severity and prognosis depend largely on the host's immune status.
Insights
Scedosporium inflatum causes diverse human infections, ranging from localized disease in immunocompetent individuals to severe disseminated infections in immunocompromised patients. Antifungal resistance is a concern, with outcomes heavily influenced by host immune status.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Clinical Microbiology
Background:
- Scedosporium inflatum is an emerging fungal pathogen.
- Human infections with Scedosporium species are increasingly recognized.
- Limited data exists on the clinical spectrum and antifungal susceptibility of S. inflatum.
Purpose of the Study:
- To describe the clinical manifestations and outcomes of human Scedosporium inflatum infections and colonization.
- To evaluate the antifungal susceptibility of S. inflatum isolates.
- To determine the impact of host immune status on disease severity and prognosis.
Main Methods:
- Retrospective case series of 17 patients in Australia.
- Classification of patients into immunocompetent, immunocompromised, and colonized groups.
- Antifungal susceptibility testing using disk diffusion and agar dilution methods.
Main Results:
- Clinical spectrum ranged from localized infections (joint, nail, eye, sinus) to disseminated disease.
- Immunocompromised patients had poor outcomes, with high mortality despite antifungal therapy.
- Asymptomatic colonization was observed in the ear and respiratory tract.
- S. inflatum isolates demonstrated resistance to multiple antifungal agents.
- One case showed clinical response to itraconazole despite a high minimum inhibitory concentration (MIC).
Conclusions:
- Scedosporium inflatum causes a broad range of human infections, with severity dependent on host immunity.
- Antifungal resistance is a significant challenge in managing S. inflatum infections.
- Further research is needed to establish effective treatment strategies for S. inflatum infections.