Scedosporium species: emerging agents of systemic disease

Recently, fundamental taxonomic changes have been proposed in Scedosporium and its sexual phase Pseudallescheria. The most common currently accepted taxa, P apiosperma and P boydii, are molecular siblings distinguished by tubulin and calmodulin genes, but with limited morphological and physiological discriminative parameters. In regions with temperate climates, these two species represent, together with S prolificans, the most prevalent agents in human infections. Therefore, validated molecular tools for routine identification are urgently needed for clinical diagnostics, as well as for epidemiology and studies on antifungal susceptibility patterns. This review provides an overview of state-of-the-art taxonomy; isolation and molecular identification; predisposing factors and risk assessment; pathogenicity, with a focus on systemic and disseminated infections; and in vitro susceptibility.