Comparison of the virulence of Scedosporium prolificans strains from different origins in a murine model.

Scedosporium prolificans is an emerging opportunist fungus that causes different types of infections in immunocompetent and immunosuppressed people. These infections show an irregular geographical distribution and, generally, disseminated systemic infections are noticed only in specific countries. This study used a murine model of disseminated infection by this fungus to assess if strains from different origins have different virulence. Two strains from each of four different sources (disseminated infection, localised infection, asymptomatic cystic fibrosis patients and the environment) were tested. Two strains of S. apiospermum of clinical origin were also included in the study; these were clearly less virulent than those of S. prolificans. The S. prolificans strains tested were classified in three groups according to their virulence. The groups with higher and lower virulence were represented by only one strain each, and the intermediate group contained six strains. No significant differences were found between the strains from different geographic areas or different forms of disease.