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

BRITO DEVOTO, TOMAS; MARTORELL, MARIA M.; HERMIDA ALAVA, K; ETCHECOPAZ, AN; POLA, SJ; MARTORELL MM; ANSALDO, MARTIN; NEGRETE, JAVIER; RUBERTO LAM; MAC CORMACK, WALTER; CUESTAS, LUJAN

NEW ZEALAND VETERINARY JOURNAL

NEW ZEALAND VETERINARY ASSOC INC

Año: 2022

0048-0169

Aims: To survey the diversity of fungal species that may be cultured from Antarctic penguinsand pinnipeds, and to test the in vitro susceptibility to triazole drugs of any medically importantAspergillus 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 (Arctocephalus gazella), elephant seals (Miroungaleonine), leopard seals (Hydrurga leptonyx), Weddell seals (Leptonychotes weddellii) andcrabeater seals (Lobodon carcinophaga) and gentoo penguins (Pygoscelis papua). Oral, nasaland rectal swabs and skin/hair brushings were collected from pinnipeds, and skin/featherbrushings, cloacal swabs and moulted feathers from penguins. Samples were cultured onSabouraud dextrose agar and/or potato dextrose agar plates and fungal isolates identifiedby morphological criteria followed by PCR amplification and DNA sequencing. Antifungalsusceptibility of Aspergillus spp. isolates to triazoles was tested.Results: Fungi from 21 genera were isolated from 121/212 (57.1%) samples obtained frompinnipeds and penguins. Among pinnipeds from Potter Peninsula (fur seals and elephantseals), the most frequent fungal species were Debaryomyces hansenii and Rhodotorulamucilaginosa, isolated from the oral, nasal and/or rectal mucosa, and Antarctomycespsychrotrophicus isolated from the skin/hair of all sampled individuals. Among pinnipedsfrom Primavera Cape (leopard seals, Weddell seals and crabeater seals), the most frequentfungal species were Naganishia adeliensis and Cryptococcus neoformans var. uniguttulatus,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), werePseudogymnoascus pannorum and A. pyschrotrophicus, which both were isolated from skin/feathers of 7/15 (46.7%) birds, and Thelebolus microsporus, isolated from the cloacal mucosaand skin/feathers of 5/15 (33.3%) and 2/15 (13.3%) birds, respectively. Fungi that arepotentially pathogenic to both humans and animals (Aspergillus fumigatus, Asp. flavus, Asp.versicolor, Candida parapsilosis and Microsporum canis) 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 nonazole-resistant isolates of Asp. fumigatus and Asp. flavus were identified.Conclusions: The fungal biodiversity in Antarctic pinnipeds and gentoo penguins wasexplored using standard mycological culture followed by PCR and DNA sequencing. Thefrequency of fungal carriage varied among animal species, sample type and location. Thisstudy constitutes an epidemiologic approach to monitoring of these marine animals foremerging fungal pathogens.