Survey of Keratinophilic Fungi from Feathers of Birds in Tuscany

Birds represent an effective mechanism for spreading microorganisms because they can travel great distances. The present study presents the results of an extensive survey carried out to evaluate the occurrence of keratinophilic molds on several avian species from Tuscany (central Italy). These fungal species encompass several keratin-degrading fungi, frequently responsible for skin disease in both human patients and animals. Despite the fact that molds more frequently isolated belong to dark fungi, keratinophilic species, including a dermatophyte species responsible for human and animal tinea, were cultured in large amounts, mostly from terrestrial avian species. This finding could be due to the high water content in nests of aquatic birds, which is unsuitable for the spreading of keratinophilic molds, and due to the antidermatophytic action of the larger amounts of uropygial gland secretions produced by waterfowls when compared to terrestrial birds. Our findings confirm the important role of migrating birds in the dispersal of pathogenic and saprophytic fungi to other environments, with an evolutionarily important consequence of genetic mixing of fungal population throughout the world. Although keratinophilic fungi on avian feathers have been widely described, data from European literature are quite lacking regarding Mediterranean countries. The aim of the present study was therefore to evaluate the occurrence of fungal species on feathers of different avian species in Italy. A total of 378 feather samples from both aquatic (n = 254) and terrestrial birds (n = 124), for a total of 30 bird species, were cultured for keratinophilic fungi. Fungal isolates were recognized by their macro- and micro-scopical morphology, and results were corroborated by PCR and sequencing. Keratinophilic fungi belonging to 11 different species (Scopulariopsis brevicaulis, Chrysosporium keratinophilum, Trichophyton terrestre, Microsporum gypseum, Sepedonium sp., Chrysosporium pannorum, Myriodontium sp., Chrysosporium tropicum, Chrysosporium pruinosum, Chrysosporium luteum and Aphanoascus fulvescens) were isolated from 71 animals (18.8%). The frequency of isolation of keratinophilic species from terrestrial birds was significantly higher in waterfowl. Migratory birds in Italy have been proven to carry pathogenic fungi such as dermatophytes, (A. platyrhyncos, A. crecca, E. rubecula), besides saprophytic species.