Genetic relationships of twenty strains of Scedosporium, Petriella and Pseudallescheria were studied by sequencing a 370 bp part of the
gene which encodes the large subunit ribosomal RNA (LSU rDNA). This study confirms and specifies earlier results from the small
subunit ribosomal RNA gene (SSU rDNA).
It was confirmed that the pathogenic Scedosporium prolificans is closely related to Petriella, as is Graphium tectonae. Petriella setifera,
which includes clinically isolated Scedosporium strains, can be divided into several groups inside the same genus.
The main part of Pseudallescheria is clearly distinguished from Petriella. Pseudallescheria is heterogeneous, however: Ps. africana is
referred to Petriella and Ps. fimeti is more closely related to Microascus.