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 in vitro susceptibility to triazole drugs of any medically important Aspergillus 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 (Mirounga leonine), leopard seals (Hydrurga leptonyx), Weddell seals (Leptonychotes weddellii) and crabeater seals (Lobodon carcinophaga) and gentoo penguins (Pygoscelis papua). 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 Aspergillus 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 Debaryomyces hansenii and Rhodotorula mucilaginosa, isolated from the oral, nasal and/or rectal mucosa, and Antarctomyces psychrotrophicus 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 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), were Pseudogymnoascus pannorum and A. pyschrotrophicus, which both were isolated from skin/feathers of 7/15 (46.7%) birds, and Thelebolus microsporus, 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 (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 non-azole-resistant isolates of Asp. fumigatus and Asp. flavus 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.

Sporotrichosis caused by Sporothrix brasiliensis in Argentina: Case report, molecular identification and in vitro susceptibility pattern to antifungal drugs.

Sporotrichosis is considered a neglected disease of humans and animals in many regions of the world and is the most frequent implantation mycosis in Latin America. OBJECTIVES: To illustrate the zoonotic importance of the disease, describing a case involving a veterinarian and an infant that acquired the disease from a domestic cat and to describe, genotype and characterize these new isolates. METHODS: Direct examination of tissue samples from the two patients and feline lesions revealed the presence of Sporothrix yeast-like organisms. Fungal cultures and molecular identification of the strains were performed. Since antifungal susceptibility data of animal-borne isolates are scarce, the in vitro susceptibility testing by a microdilution reference method was determined against azoles, amphotericin B and terbinafine. RESULTS: Fungal culture and sequence analysis of the ITS region of rDNA and calmodulin and ß-tubulin genes confirmed the diagnosis and the causative agent as Sporothrix brasiliensis. In all cases, terbinafine was the most active drug, followed by posaconazole, itraconazole and voriconazole; the least active drugs were amphotericine B and fluconazole. Lack of clinical response in the veterinarian and in the infant to itraconazole and potassium iodide, respectively was observed. CONCLUSIONS: This study contributed to the molecular epidemiology of Sporothrix species in Argentina and the characterization of the in vitro susceptibility pattern of S. brasiliensis isolates recovered from a cat and two humans involved in this case of zoonotic sporotrichosis. Bearing in mind the "One Health" concept, the experience described in the present study highlights the need for future strategies for sporotrichosis treatment, control and prevention.

Phenotypic and genotypic identification of Candida dubliniensis from subgingival sites in immunocompetent subjects in Argentina.

INTRODUCTION: It is generally recognized that Candida dubliniensis is commonly found in immunocompromised patients, such as those with advanced human immunodeficiency virus infection, at sites of periodontal disease. Since there are no data available for Argentina, the aim of this study was to determine the prevalence of and to identify C. dubliniensis in periodontal pockets from immunocompetent subjects living in Buenos Aires, Argentina, through a comparison of phenotypic and molecular assays. METHODS: Yeasts recovered from subgingival plaque samples were studied for 180 immunocompetent non-smoking patients with periodontal disease. Yeasts were identified by conventional mycological methods and by specific polymerase chain reaction (PCR) assay. Fluconazole and voriconazole susceptibility studies were performed in keeping with the Clinical and Laboratory Standards Institute. RESULTS: Among 76 yeasts isolated, C. dubliniensis comprised 10.5% (n = 8; 95% confidence interval 4.7-19.7), which corresponded to 4.4% of patients studied (8/180). C. albicans was the most frequently isolated species of yeast. A great majority of C. dubliniensis isolates was susceptible with only one isolate resistant to both antifungals. CONCLUSION: Micromorphology on Staib agar was the phenotypic method that was most concordant with PCR and it was useful for selecting presumptive C. dubliniensis. This is the first report to use PCR to identify C. dubliniensis in subgingival fluid from immunocompetent individuals with periodontal disease in Argentina. On the basis of the findings presented here, we confirm that C. dubliniensis can colonize periodontal pockets of immunocompetent patients with periodontal disease.