Cutaneous and Systemic Pathogenicity of a Clinical Isolate of Cladosporium sphaerospermum in a Murine Model

The pathogenicity of a clinical isolate of Cladosporium sphaerospermum was determined in a murine model. BALB/c mice were given two intraperitoneal injections of 150 mg/kg cyclophosphamide or normal saline on days 4 and 1 preinoculation, and were then challenged with 0.2 ml of C. sphaerospermum inoculum (2 × 107 CFU/ml) by topical application on an abrasive wound or by subcutaneous or intravenous injection. Histopathology and inverse fungal culture were performed on the skin lesions and viscera, and pulmonary fungal burden was also determined. Inoculated skin developed localized infections after dermabrasive or subcutaneous challenge in all mice, but the maximum area and number of positive cultures from skin lesions were higher for immunocompromised mice. In the intravenously inoculated mice, all immunocompetent animals survived for the 4-week period of the experiment, while 60% of immunocompromised animals died by 5 days postinoculation. The incidence of disseminated infection and the pulmonary fungal burden of immunosuppressed mice were higher than those of immunocompetent animals. Cutaneous and systemic infections can be established by subcutaneous and intravenous challenge with C. sphaerospermum in BALB/c mice, with the lungs being the most susceptible tissue in systemic infection.