Sporothrix brasiliensis is an emerging fungal pathogen whose environmental reservoirs remain unclear. There are hypothesized reservoirs involving seabirds.
Case reportWe report the first detection of S. brasiliensis in a Macronectes giganteus specimen rescued in southern Brazil. The fungus was isolated from the cloaca and identified by polymerase chain reaction (PCR) and sequencing. Short tandem repeat (STR) genotyping revealed a distinct profile of the isolate compared to previously described strains. The results revealed that the isolate possessed a wild-type susceptibility profile to amphotericin B and itraconazole, and a non-wild-type susceptibility profile to terbinafine.
ConclusionsFindings suggest that migratory seabirds and marine environments may influence S. brasiliensis dissemination, underscoring the need for broader One Health surveillance at a global level.
Sporothrix brasiliensis es un patógeno fúngico emergente, cuyos reservorios ambientales siguen siendo poco claros. Algunas hipótesis apuntan a las aves marinas como posibles reservorios.
Caso clínicoReportamos el aislamiento de S. brasiliensis por primera vez en un ejemplar de Macronectes giganteus rescatado en el sur de Brasil. El hongo fue aislado de la cloaca del animal e identificado mediante reacción en cadena de la polimerasa (PCR) y secuenciación. La genotipificación por repeticiones cortas en tándem (STR) reveló la existencia en el aislamiento de un perfil distinto en comparación con cepas previamente descritas. Se detectó un perfil de sensibilidad tipo silvestre para la anfotericina B y el itraconazol, y un perfil de sensibilidad no silvestre para la terbinafina.
ConclusionesLos hallazgos sugieren que las aves marinas migratorias y los ambientes marinos pueden influir en la diseminación de S. brasiliensis, lo que refuerza la necesidad de una vigilancia más amplia bajo el enfoque de Una Salud (One Health) a nivel global.
Sporothrix genus includes over 50 species in environmental and clinical clades.1 The clinical clade comprises Sporothrix brasiliensis, Sporothrix schenckii, Sporothrix globosa, and Sporothrix luriei.4S. brasiliensis is primarily spread through bites and scratches from infected cats, making it a key zoonotic pathogen, while the other three species are mainly environmentally transmitted.1,21 Zoonotic sporotrichosis outbreaks were first reported in Brazil in the 1990s, in Rio de Janeiro and Rio Grande do Sul.2,9 It is now a major public health issue in Brazil and neighboring countries and is considered an emerging global concern.21 Early cases in coastal areas suggest a link between S. brasiliensis and saline environments12; fish-related traumatic infections have also been documented.7
Despite its clinical importance, little is known about the environmental habitat of S. brasiliensis. Although isolated from soil in coastal and hyperendemic areas, its ecological niche remains unclear,11,13 highlighting the need to investigate potential reservoirs, especially in marine ecosystems, and their role in its spread. Furthermore, the detection of S. brasiliensis DNA by metabarcoding in Antarctic soil serves to further encourage studies of this nature, thereby contributing to a One Health perspective and to a more comprehensive understanding of S. brasiliensis dispersion.15 Migratory birds, particularly marine species, may disperse fungal pathogens, as seen with azole-resistant Aspergillus.8 These birds can transport emerging fungi across countries and even to Antarctica. The emergence of S. brasiliensis in Patagonia18 may relate to migratory routes connecting Antarctic/sub-Antarctic regions, Brazil, and Chile. Understanding coastal environmental roles in S. brasiliensis transmission is still needed. Here, we report the isolation of a S. brasiliensis strain that had colonized the cloaca of a Southern Giant Petrel (Macronectes giganteus) from southern Brazil.
A juvenile female Southern Giant Petrel, dehydrated and lethargic, was rescued on August 6th, 2022, at Cassino Beach, southern Brazil (Fig. 1). The animal was taken to a rehabilitation center (CRAM/FURG), where oral and cloacal swabs were collected and sent to the Mycology Laboratory – FURG. Samples were cultured on Sabouraud dextrose agar with chloramphenicol and incubated at 25°C for 15 days. Despite intensive care, the animal deteriorated and died 24h after admission. Necropsy showed no macroscopic lesions, but a large amount of stomach debris. Histopathology revealed marked diffuse pulmonary congestion without digestive tract alterations, yielding an inconclusive cause of death.
(A) Map of South America highlighting the city of Rio Grande, in the state of Rio Grande do Sul, Brazil, where Cassino Beach is located, as well as the migratory route and distribution area of the Southern Giant Petrel (Macronectes giganteus). (B) Specimen of Southern Giant Petrel from which Sporothrix brasiliensis was isolated. (C) Plate showing a subculture of the S. brasiliensis strain isolated from the cloacal mucosa of the bird. (D) Microscopic view of the S. brasiliensis strain (400× magnification.).
After five days of incubation, a filamentous colony obtained from the cloacal sample was identified as Sporothrix sp. based on macroscopic and microscopic features (Fig. 1). After genomic DNA extraction,20 species confirmation was achieved by S. brasiliensis-specific polymerase chain reaction and calmodulin gene sequencing14 (GenBank accession number: PX939563). Sequences were aligned using MEGA 5.2.2 and confirmed by BLAST analysis. The isolate was also subjected to short tandem repeat (STR) analysis targeting tri- and hexanucleotide repeats, with copy number assessed on a 3500XL genetic analyzer17 and compared with previously genotyped strains (Fig. 2).5 These control strains were all clinical and had been collected from humans, cats or dogs between 2012 and 2025. Antifungal susceptibility to amphotericin B, itraconazole, and terbinafine was assessed using CLSI-M38-A2. Epidemiological cutoff values (ECVs) were 4μg/mL, 2μg/mL, and 0.125μg/mL, respectively.6 The isolate was wild-type for amphotericin B (2μg/mL) and itraconazole (0.5μg/mL), but non-wild-type for terbinafine (4μg/mL).
Genetic comparison of the Sporothrix brasiliensis strain isolated from the cloaca of a Macronectes giganteus specimen with previously genotyped isolates, based on short tandem repeat genotyping. Minimum spanning tree illustrates the genetic relationships between the S. brasiliensis isolate obtained from the cloaca of the bird and other strains reported in the literature. Branch lengths indicate levels of genetic variation between isolates: thick solid lines (variation in one short tandem repeat-STR marker), thin solid lines (variation in two markers), thin dashed lines (variation in three markers), and thin dotted lines (variation in four or more markers).
The present study reports the first documented case of S. brasiliensis colonization in a migratory seabird, the Southern Giant Petrel,19 thereby contributing to the expansion of knowledge regarding the dispersal of this pathogen. The finding suggests marine ecosystems may act as niches, and migratory seabirds as dispersers. Supporting this hypothesis, early outbreaks occurred along the Brazilian coast and recent cases were reported in Chilean Patagonia, regions overlapping the migratory routes of M. giganteus.10,12,19,21
Southern giant petrels are known to migrate from the Antarctic region to as far north as São Paulo, Brazil. However, their highest incidence in Brazil occurs in the state of Rio Grande do Sul,10,16 our region. An interesting aspect of this species is its feeding behavior. Southern giant petrels are opportunistic predators and scavengers, feeding on live vertebrate prey, as well as the carcasses of birds, fish and marine mammals.21 They are also frequently observed following fishing boats to feed on discards. These feeding habits may bring them into close contact with a wide range of animal species and human activities, potentially influencing their microbiota.3 This ecological behavior may help explain the potential transmission and host-switching of S. brasiliensis isolated from the cloaca of the petrel.
The S. brasiliensis isolate analyzed in this study exhibited a unique genotype when compared to previously documented strains.5 Interestingly, it also did not cluster within the major clade described in the literature, which predominantly comprises isolates from the Brazilian states Paraná and Rio de Janeiro. Instead, it grouped more closely with isolates from the southern and southeastern regions of Brazil, including strains from Rio Grande do Sul,17 suggesting a distinct genetic background that aligns with its geographic context and potentially brings insights of local transmission dynamics. Regarding antifungal susceptibility, the isolate was identified as non-wild-type for terbinafine. This highlights the need for future studies to investigate the mechanisms underlying the reduced terbinafine susceptibility in S. brasiliensis, as well as the potential role of the environment and wild animals in generating or disseminating this non-susceptibility condition.
The limitations of this study include its design as a single case report, providing data from only one animal and one sample (as the bird died within 24h). Consequently, we lack information to support a robust interpretation of this finding, and it remains uncertain whether S. brasiliensis constitutes a permanent or transient part of this and other seabirds, whether in the specimen affected it was acquired through ingestion of contaminated garbage or animal carcasses, or whether it originated from Antarctic/subantarctic regions where these birds breed. Despite these limitations, the novelty of this finding serves as an alert and underscores the urgency of further studies to address these questions.
In conclusion, our study reports novel insights on the potential transmission dynamics of S. brasiliensis, the main emerging agent of sporotrichosis. It underscores the urgent need for a One Health approach to expand both animal and environmental surveillance efforts, including Antarctic/Subantarctic regions, to better understand the ecology and transmission of S. brasiliensis. Additionally, it emphasizes the importance of investigating other marine animals as potential reservoirs and/or dispersers of this pathogen, including strains with wild-type and non-wild-type susceptibility profiles to antifungal drugs.
ORCID IDMariana Rodrigues Trápaga: 0000-0003-1407-8135
Jessica E. Dávila Hidalgo: 0009-0003-3178-0943
Lívia Silveira Munhoz: 0000-0002-3538-5006
Aryse Martins Melo: 0000-0002-6655-8715
Paula Lima Canabarro: 0009-0001-5413-5301
Theun de Groot: 0000-0001-5841-6461
Bram Spruijtenburg: 0000-0002-6734-361X
Eelco F.J. Meijer: 0000-0002-0226-024X
Melissa Orzechowski Xavier: 0000-0002-3883-0080
Authors’ contributionsConceptualization: Vanice Rodrigues Poester, Mariana Rodrigues Trápaga and Melissa Orzechowski Xavier; Methodology: Mariana Rodrigues Trápaga, Jessica E. Dávila Hidalgo, Lívia Silveira Munhoz, Aryse Martins Melo, Emanoel Bartz Tapi, Paula Lima Canabarro, and Bram Spruijtenburg; Formal analysis: Vanice Rodrigues Poester, Mariana Rodrigues Trápaga, Paula Lima Canabarro, Bram Spruijtenburg and Melissa Orzechowski Xavier; Writing – original draft preparation: Vanice Rodrigues Poester and Mariana Rodrigues Trápaga; Writing – review and editing: Theun de Groot, Bram Spruijtenburg, Eelco F.J. Meijer, and Melissa Orzechowski Xavier. All authors have read and agreed to the published version of the manuscript.
Conflict of interestAll authors declare that they have no conflicts of interest pertaining to this work.
The authors are grateful to Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ), Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS number: 24/2551-0000720-2; 25/2551-0000888-3, and 25/2551-0002804-3), and Pesquisa Ecológica de Longa Duração no Estuário da Lagoa dos Patos e Costa Marinha Adjacente.
