Abstract
One hundred clinical isolates from a prospective nationwide study of scedosporiosis in Australia (2003-2005) and 46 additional isolates were genotyped by internal transcribed spacer-restriction fragment length polymorphism (ITS-RFLP) analysis, ITS sequencing, and M13 PCR fingerprinting. ITS-RFLP and PCR fingerprinting identified 3 distinct genetic groups. The first group corresponded to Scedosporium prolificans (n = 83), and the other 2 comprised isolates previously identified as S. apiospermum: one of these corresponded to S. apiospermum (n = 33) and the other to the newly described species S. aurantiacum (n = 30). Intraspecies variation was highest for S. apiospermum (58%), followed by S. prolificans (45%) and S. aurantiacum (28%) as determined by PCR fingerprinting. ITS sequence variation of 2.2% was observed among S. apiospermum isolates. No correlation was found between genotype of strains and their geographic origin, body site from which they were cultured, or colonization versus invasive disease. Twelve S. prolificans isolates from 2 suspected case clusters were examined by amplified fragment length polymorphism analysis. No specific clusters were confirmed.
Highlights
Despite efforts to identify and eliminate infectious agents, they continue to emerge and reemerge [1]
In particular that caused by S. prolificans, is often refractory to treatment [3,5], preventive strategies are of paramount importance
Scedosporium isolates were associated with invasive disease in 46 (38.3%) instances; Table 1
Summary
Despite efforts to identify and eliminate infectious agents, they continue to emerge and reemerge [1]. In contrast to the well-documented opportunists Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus, the epidemiology and evolution of human infections caused by uncommon but emerging fungi are incompletely understood. Such pathogens include Scedosporium apiospermum (teleomorph Pseudallescheria boydii) and S. prolificans, which are inherently resistant to many antifungal agents [3,4,5]. S. apiospermum infections occur worldwide, ranging from localized mycetomas to deep-seated disease such as cerebral abscesses [6,7] This species colonizes the respiratory tract of ≈10% of patients with cystic fibrosis and chronic suppurative lung disease [8,9,10]. We searched for the newly described species, S. aurantiacum and for genetic clustering of strains according to their geographic origin, body site from which they were cultured, and ability to cause invasive disease
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