Exploring fungal diversity in Antarctic wildlife: isolation and molecular identification of culturable fungi from penguins and pinnipeds.

Aims: To survey the diversity of fungal species that may be cultured from Antarctic penguins and pinnipeds, and to test the susceptibility to triazole drugs of any medically important s spp. isolates.

Methods: During an expedition to Argentinean Antarctic research stations at Potter Peninsula (South Shetland Islands) and Primavera Cape (Antarctic Peninsula) in February 2019, samples (n = 212) were collected from fur seals (), elephant seals (), leopard seals (), Weddell seals () and crabeater seals () and gentoo penguins (). Oral, nasal and rectal swabs and skin/hair brushings were collected from pinnipeds, and skin/feather brushings, cloacal swabs and moulted feathers from penguins. Samples were cultured on Sabouraud dextrose agar and/or potato dextrose agar plates and fungal isolates identified by morphological criteria followed by PCR amplification and DNA sequencing. Antifungal susceptibility of spp. isolates to triazoles was tested.

Results: Fungi from 21 genera were isolated from 121/212 (57.1%) samples obtained from pinnipeds and penguins. Among pinnipeds from Potter Peninsula (fur seals and elephant seals), the most frequent fungal species were and , isolated from the oral, nasal and/or rectal mucosa, and isolated from the skin/hair of all sampled individuals. Among pinnipeds from Primavera Cape (leopard seals, Weddell seals and crabeater seals), the most frequent fungal species were and var. , isolated from the nasal/oral mucosa of 4/33 (15.2%) and 5/33 (12.1%) animals, respectively. The most frequently isolated fungal species from gentoo penguins (Potter Peninsula), were and , which both were isolated from skin/feathers of 7/15 (46.7%) birds, and , isolated from the cloacal mucosa and skin/feathers of 5/15 (33.3%) and 2/15 (13.3%) birds, respectively. Fungi that are potentially pathogenic to both humans and animals ( and ) were isolated from 4/38 (10.5%), 1/38 (2.6%), 2/38 (5.3%), 4/38 (10.5%) and 2/38 (5.3%) sampled pinnipeds, respectively. Only non-azole-resistant isolates of and were identified.

Conclusions: The fungal biodiversity in Antarctic pinnipeds and gentoo penguins was explored using standard mycological culture followed by PCR and DNA sequencing. The frequency of fungal carriage varied among animal species, sample type and location. This study constitutes an epidemiologic approach to monitoring of these marine animals for emerging fungal pathogens.