Yeasts vectored by migratory birds collected in the Mediterranean island of Ustica and description of Phaffomyces usticensis f.a. sp. nov., a new species related to the cactus ecoclade.

Nine yeast species belonging to genera Candida, Cryptococcus, Phaffomyces,Rhodotorula and Wickerhamomyces, and one species of Aureobasidium genuswere isolated from the cloaca of migratory birds. Candida glabrata andC. inconspicua were the species most frequently isolated and Wickerhamomycessylviae, which has recently been described as a new species isolated from birdcloaca, was again found. The majority of isolates showed the ability to grow upto 40 °C and/or at pH 3.0, two environmental conditions typical of the digestivetract of birds. The phylogenetic analysis of the D1/D2 domain of 26SrRNA gene placed the cultures of Phaffomyces in a new lineage that differedfrom the closest species, P. opuntiae, by 13 nucleotide substitutions. The newspecies was able to grow at 40 °C and at pH 2.5, which suggests a possibleadaptation to the bird cloaca. Moreover, the ability to grow in the presence ofdigitonin at pH 3.7 and the assimilation of ethyl acetate indicates a potentialcactophilic origin. For the first time, the presence of yeasts belonging to thePhaffomyces clade in Europe and also in non-cactus environments is reported.The new species is formally described as P. usticensis sp. nov. (PYCC6346T = CBS 12958T).