Sporothrix brasiliensis and cats: understanding the disease and the promising potential of veterinary antifungal vaccination for a healthier future of both humans and animals

Refractory sporotrichosis lesion: An effective and pioneering approach in a patient living with human immunodeficiency virus/acquired immunodeficiency syndrome

Sporotrichosis is a cosmopolitan subcutaneous mycosis caused by Sporothrix species. Recently, this mycosis has gained notoriety due to the appearance of new endemic areas, recognition of new pathogenic species, changes in epidemiology, occurrence of outbreaks, and increasing numbers of cases. The purpose of this study is to analyze the peculiarities of sporotrichosis cases in Brazil since its first report in the country until 2020. In this work, ecological, epidemiological, clinical, and laboratorial characteristics were compiled. A systematic review of human sporotrichosis diagnosed in Brazil and published up to December 2020 was performed on PubMed/MEDLINE, SciELO, Web of Science, and LILACS databases. Furthermore, animal sporotrichosis and environmental isolation of Sporothrix spp. in Brazil were also evaluated. The study included 230 papers, resulting in 10,400 human patients. Their ages ranged from 5months to 92years old and 55.98% were female. The lymphocutaneous form was predominant (56.14%), but systemic involvement was also notably reported (14.34%), especially in the lungs. Besides, hypersensitivity manifestations (4.55%) were described. Most patients had the diagnosis confirmed by isolation of Sporothrix spp., mainly from skin samples. Sporothrix brasiliensis was the major agent identified. HIV infection, cardiovascular diseases, and diabetes were the most common comorbidities. Cure rate was 85.83%. Concerning animal sporotrichosis, 8538 cases were reported, mostly in cats (90.77%). Moreover, 13 Sporothrix spp. environmental strains were reported. This review highlights the burden of the emergent zoonotic sporotrichosis in Brazil, reinforcing the importance of "One Health" based actions to help controlling this disease.

In this study, the human immune response mechanisms against Sporothrix brasiliensis and Sporothrix schenckii, two causative agents of human and animal sporotrichosis, were investigated. The interaction of S. brasiliensis and S. schenckii with human monocyte-derived macrophages (hMDMs) was shown to be dependent on the thermolabile serum complement protein C3, which facilitated the phagocytosis of Sporothrix yeast cells through opsonization. The peptidorhamnomannan (PRM) component of the cell walls of these two Sporothrix yeasts was found to be one of their surfaces exposed pathogen-associated molecular pattern (PAMP), leading to activation of the complement system and deposition of C3b on the Sporothrix yeast surfaces. PRM also showed direct interaction with CD11b, the specific component of the complement receptor-3 (CR3). Furthermore, the blockade of CR3 specifically impacted the interleukin (IL)-1β secretion by hMDM in response to both S. brasiliensis and S. schenckii, suggesting that the host complement system plays an essential role in the inflammatory immune response against these Sporothrix species. Nevertheless, the structural differences in the PRMs of the two Sporothrix species, as revealed by NMR, were related to the differences observed in the host complement activation pathways. Together, this work reports a new PAMP of the cell surface of pathogenic fungi playing a role through the activation of complement system and via CR3 receptor mediating an inflammatory response to Sporothrix species.

Sporothrix brasiliensis has emerged as an important cause of sporotrichosis, particularly associated with feline and zoonotic cases. Owing to the paucity of data on antifungal activity against this species, the present study aimed to evaluate the in vitro susceptibility of clinical isolates of S. brasiliensis in the mycelial and yeast phases to itraconazole (ITZ), terbinafine (TRB), and amphotericin B (AMB). Thirty-five isolates from an outbreak of feline sporotrichosis in Southern Brazil were used. All of them were assessed in the yeast and filamentous phases using the broth microdilution technique in accordance with the respective reference protocols M27-A3 and M38-A2 of the Clinical and Laboratory Standards Institute (CLSI). In our study, TRB was the most active antifungal against both the filamentous and yeast phases, showing GM of the MIC of 0.343μg/ml and 0.127μg/ml, respectively. In the yeast phase, the GM of the MIC for TRB was significantly lower than that for both ITZ (P = .009) and AMB (P < .001). However, in the filamentous phase, the GM of the MIC for TRB was significantly lower than that of AMB (P < .001), but not different from that of ITZ (P = .091). AMB was the antifungal with the highest GM of the MIC for both phases (1.486μg/ml for the filamentous phase and 0.660μg/ml for the yeast). Our results may contribute to a better understanding of antifungal susceptibility profiles of clinical isolates of S. brasiliensis in the mycelial and yeast phases in further studies.

Sporotrichosis is a neglected fungal zoonosis with significant impacts on human and animal health. Accurate diagnosis, treatment, and understanding of the transmission dynamics of Sporothrix species are essential for mitigating the spread of sporotrichosis. This study aimed to identify the Sporothrix species involved in the ongoing outbreaks of animal sporotrichosis in the metropolitan region of Belo Horizonte, Minas Gerais, Brazil, and analyse the phylogenetic relationships between pathogenic species to investigate the outbreak origin. Additionally, to better understand the evolution of the disease, we conducted a retrospective survey of positive feline and canine cases from November 2017 to July 2021 with proven cultures for Sporothrix. A significant increase in animal cases over the last 4 years was observed, with cats being the most affected host. Sporothrix brasiliensis was the predominant agent in 100% of the clinical isolates (n = 180) molecularly identified. Phylogenetic and haplotype analysis points towards the cases isolated from Minas Gerais sharing the haplotype originating from a long-lasting outbreak of cat-transmitted sporotrichosis in Rio de Janeiro, however, with a secondary contribution from genotypes circulating in other outbreaks in Brazil. Thus, we present clear evidence of the circulation of different S. brasiliensis genotypes associated with animal sporotrichosis in the metropolitan region of Belo Horizonte. Genetic monitoring can contribute to understanding the causal agent for zoonotic sporotrichosis in epidemiological processes and help to implement disease prevention and control measures.

Sporothrix brasiliensis is the prevalent agent of a large zoonotic outbreak in Brazil. With the involvement of several thousands of cases, this is the largest cohort of human and animal sporotrichosis on record in the world. Infections are characterized by local cutaneous dissemination in humans without underlying disease. S.brasiliensis has shown a high degree of virulence in a mouse model compared to the remaining Sporothrix species, including the ancestral species, Sporothrix schenckii The present paper investigates a genomic and expressed-proteome comparison of S.brasiliensis to S.schenckii Using bottom-up proteomics, we found 60 proteins exclusively expressed in S.brasiliensis No significant genomic differences were found among the genes coding for this protein set. A comparison with literature data identified nine proteins that are known to be involved in virulence and immune evasion in other species, several of which had not yet been reported for the Sporothrix species analyzed.IMPORTANCE Sporotrichosis is an important disease in Brazil that is caused by fungi of the genus Sporothrix and affects cats and humans. Our work investigated the proteins differentially expressed by S.brasiliensis in order to find out why this species is more virulent and pathogenic than S.schenckii We verified a set of proteins that may be related to immune escape and that can explain the high virulence.

Live-attenuated bacterial veterinary vaccines can constitute an infection risk for individuals with any defect in their phagocytic function, including chronic granulomatous disease, leukocyte adhesion deficiency, myeloperoxidase deficiency, as well as Chediak-Higashi syndrome, from accidental acquisition of licenced attenuated live bacterial vaccine, at vaccination or from their vaccinated pet. Ownership of small companion animals, including cats and dogs, is popular within the cystic fibrosis (CF) community. These animals require vaccines as part of their routine care, which may involve live viral and bacterial vaccines, with potential for infection in the CF owner. This report examines the scope of current canine and feline vaccines, with particular emphasis on veterinary vaccination strategies against the Gram-negative pathogen, Bordetella bronchiseptica and describes new vaccine innovations offering protection to both pet and CF owner. The Gram-negative bacterium, Bordetella bronchoseptica, may cause respiratory disease in small companion animals, as well as in certain human vulnerable groups, including those with CF. Live licenced veterinary bacterial vaccines for Bordetella bronchiseptica (Kennel Cough) are available for cats and dogs, which are an infection concern for humans with CF who may come into contact with vaccinated animals. Live licenced veterinary bacterial vaccines for Bordetella bronchiseptica (Kennel Cough) are available for intranasal administration to cats and dogs. These vaccines require a withdrawal period of vaccinated animal from vulnerable owner, ranging from 35days - 11weeks. Recently, a new dead IM vaccine is now available not requiring exclusion of the vaccinated pet from CF owner. CF pharmacists, hospital pharmacists and community pharmacists are important custodians of vaccine-related advice to people with CF, who are frequently consulted for such advice. Pharmacists should be aware of the recent innovations in veterinary medicines, so that they can give appropriate advice to people with CF when asked. Immunocompromised patients, that is those with CF or those with any defect in their phagocytic function (chronic granulomatous disease, leukocyte adhesion deficiency, myeloperoxidase deficiency, Chediak-Higashi syndrome) should avoid exposure to live veterinary bacterial vaccines and seek animal vaccination utilising non-live vaccines. Most importantly, this manuscript highlights the development of a new veterinary vaccine for dogs, which we want to make the CF healthcare community aware of, which is an acellular dead vaccine, so that those patients with dogs needing annual vaccination can select this vaccine pathway, thereby minimising risk of infection from the vaccine strains and avoiding the social exclusion between CF patient and their pet. CF patients should understand the potential infection implications of live-attenuated viral and bacterial strains as vaccines, whether these are small companion animals, exotic animals or large farm animals. Patients should make their veterinarian aware of their CF status, so that a safe and efficacious vaccine strategy is used, both mitigating the potential infection risks from live vaccine components with the CF patient, but simultaneously offering maximum immunological protection to the animal.

Cat-transmitted sporotrichosis caused by Sporothrix brasiliensis is an emerging zoonosis in Latin America. Because treatment of feline sporotrichosis is often not effective, we sought to determine whether treatment failure results from S. brasiliensis strains that have existing elevated MICs for itraconazole, the primary treatment for this disease. During 2021-2023 at the triple border region of Brazil, Paraguay, and Argentina, 108 S. brasiliensis strains were isolated from felines before antifungal treatment. The main clinical manifestation was cutaneous disseminated sporotrichosis (61%), which was the only form resulting in sporotrichosis-induced deaths (61%). We conducted antifungal susceptibility testing for 9 antifungal compounds, evaluating for both mycelial and yeast phases. MIC levels were low for most antifungal agents but were higher in the mycelial phase than in the yeast phase, especially for voriconazole and isavuconazole. We conclude that the varying clinical manifestations of sporotrichosis and large differences in mortality rates were not caused by elevated itraconazole MICs.

Background Penicillium marneffei is the most important thermal dimorphic fungus causing systemic mycosis in China and Southeast Asia. While miRNAs are increasingly recognized for their roles in post-transcriptional regulation of gene expression in animals and plants, miRNAs in fungi were less well studied and their potential roles in fungal dimorphism were largely unknown. Based on P. marneffei genome sequence, we hypothesize that miRNA-like RNAs (milRNAs) may be expressed in the dimorphic fungus.Methodology/Principal FindingsWe attempted to identify milRNAs in P. marneffei in both mycelial and yeast phase using high-throughput sequencing technology. Small RNAs were more abundantly expressed in mycelial than yeast phase. Sequence analysis revealed 24 potential milRNA candidates, including 17 candidates in mycelial and seven in yeast phase. Two genes, dcl-1 and dcl-2, encoding putative Dicer-like proteins and the gene, qde-2, encoding Argonaute-like protein, were identified in P. marneffei. Phylogenetic analysis showed that dcl-2 of P. marneffei was more closely related to the homologues in other thermal dimorphic pathogenic fungi than to Penicillium chrysogenum and Aspergillus spp., suggesting the co-evolution of dcl-2 among the thermal dimorphic fungi. Moreover, dcl-2 demonstrated higher mRNA expression levels in mycelial than yeast phase by 7 folds (P<0.001). Northern blot analysis confirmed the expression of two milRNAs, PM-milR-M1 and PM-milR-M2, only in mycelial phase. Using dcl-1KO, dcl-2KO, dclDKO and qde-2KO deletion mutants, we showed that the biogenesis of both milRNAs were dependent on dcl-2 but not dcl-1 or qde-2. The mRNA expression levels of three predicted targets of PM-milR-M1 were upregulated in knockdown strain PM-milR-M1 KD, supporting regulatory function of milRNAs.Conclusions/SignificanceOur findings provided the first evidence for differential expression of milRNAs in different growth phases of thermal dimorphic fungi and shed light on the evolution of fungal proteins involved in milRNA biogenesis and possible role of post-transcriptional control in governing thermal dimorphism.

Sporotrichosis is a widespread subcutaneous mycosis caused by the dimorphic fungi now known as the Sporothrix schenckii complex. This complex is comprised of at least six species, including Sporothrix albicans, Sporothrix brasiliensis, Sporothrix globosa, Sporothrix luriei, Sporothrix mexicana and S. schenckii. Cases of sporotrichosis have significantly increased in Brazil over the past decade, especially in the state of Rio de Janeiro (RJ), where an epidemic among cat owners has been observed. The zoonotic transmission from cats to humans suggests a common source of infection and indicates that animals can act as vectors. We performed a molecular characterisation of samples collected during the first outbreak of familial sporotrichosis caused by S. brasiliensis in the state of Espírito Santo, Brazil. These results represent the first description of such an outbreak outside the endemic area of zoonotic sporotrichosis in RJ.

Sporothrix brasiliensis is an emerging fungal pathogen frequently associated with zoonotic transmission of sporotrichosis by contaminated cats. Within 25 years, the disease has spread not only throughout Brazil but now to neighboring countries in Latin America. Thermo-dimorphism, melanin, glycans, adhesins, and secreted vesicles have been associated with the ability of Sporothrix species to cause disease in the mammalian host. Although certain virulence factors have been proposed as potential determinants for sporotrichosis, the scarcity of molecular tools for performing reverse genetics in Sporothrix has significantly impeded the dissection of mechanisms underlying the disease. Here, we demonstrate that PEG-mediated protoplast transformation is a powerful method for heterologous gene expression in S. brasiliensis, S. schenckii, and S. chilensis. Combined with CRISPR/Cas9 gene editing, this transformation protocol enabled the deletion of the putative DHN-melanin synthase gene pks1, which is a proposed virulence factor of Sporothrix species. To improve in locus integration of deletion constructs, we deleted the KU80 homolog that is critical for non-homologous end-joining DNA repair. The use of Δku80 strains from S. brasiliensis enhanced homologous-directed repair during transformation resulting in increased targeted gene deletion in combination with CRISPR/Cas9. In conclusion, our CRISPR/Cas9-based transformation protocol provides an efficient tool for targeted gene manipulation in Sporothrix species. IMPORTANCE Sporotrichosis caused by Sporothrix brasiliensis is a disease that requires long periods of treatment and is rapidly spreading across Latin America. The virulence of this fungus and the surge of atypical and more severe presentations of the disease raise the need for an understanding of the molecular mechanisms underlying sporotrichosis, as well as the development of better diagnostics and antifungal therapies. By developing molecular tools for accurate genetic manipulation in Sporothrix, this study addresses the paucity of reliable and reproducible tools for stable genetic engineering of Sporothrix species, which has represented a major obstacle for studying the virulence determinants and their roles in the establishment of sporotrichosis.

Sporotrichosis is a subcutaneous mycosis diagnosed by isolation of the fungus in culture. Serological tests for help in diagnosis in general do not use purified or recombinant antigens, because there is a paucity of described immunoreactive proteins, especially for the new described Sporothrix species, such as Sporothrix brasiliensis. This study aims to characterise antigens from S. brasiliensis and verify their application in serodiagnosis of sporotrichosis. An immunoblot assay allied with computer-based analysis was used to identify putative antigenic molecules in a cell-free extracts of both morphological phases of this fungus, and to delineate antigenic polymorphism among seven S. brasiliensis isolates and one S. schenckii Brazilian strain. The mycelial and yeast phase of the fungus originated 14 and 23 reactive bands, respectively, which were variable in intensity. An 85 kDa antigen, verified in the yeast phase of the fungus, was observed in all strains used and the immunodominant protein was identified. This protein, however, cross-react with serum samples from patients infected with other pathogens. The results show that the S. brasiliensis cell-free antigen extract is a single and inexpensive source of antigens, and can be applied on the sporotrichosis serodiagnosis.

Sporotrichosis is a neglected tropical disease and the most common subcutaneous mycosis, mainly caused by Sporothrix species, particularly S. brasiliensis, S. schenckii and S. globosa, which exhibit varying biological behaviours and virulence. The epidemic of sporotrichosis in Brazil, initiated in Rio de Janeiro in the late 1990s, rapidly spread to other states, including Amazonas in 2021. This study aimed to identify the specific Sporothrix species responsible for the human sporotrichosis outbreak in the Brazilian Amazon. A cross-sectional study was conducted by enrolling clinically suspected cases of sporotrichosis attended at a reference dermatologic centre, in Manaus (Brazil). Biological material was collected from their skin lesions for culture (Mycosel) and for species identification (qPCR). Sporothrix cultures were obtained from 150 cases. Sporotrichosis predominantly affected females (67.3%), aged 44.5 years on average, with lymphocutaneous lesions (72.7%). Sporothrix brasiliensis was identified in 89.3% of patients. Up to 83.3% of these patients reported contact with cats previously to the skin lesion, and the time-spatial progression of the human cases followed the notification of cases in cats, in the metropolitan region of Manaus. Sporothrix brasiliensis is the dominant species in the zoonotic outbreak of human sporotrichosis in the Brazilian Amazon, with cats identified as the primary vectors. Effective sanitary control measures, education and responsible pet ownership are crucial to mitigating zoonotic sporotrichosis' impact in Brazil and preventing its spread to neighbouring Latin American cities.

Background: Sporotrichosis is a deep cutaneous mycosis caused by the Sporothrix species complex, dimorphic fungi of which at least five are of clinical importance: S. brasiliensis, S. globosa, S. luriei, S. mexicana, and S. schenckii sensu stricto. The disease affects humans and animals, especially cats, which can manifest a wide spectrum of clinical sings, from cutaneous-lymphatic involvement to disseminated form. Infection usually results from direct inoculation of the fungus into skin. Zoonotic transmission is associated with scratching or biting of sick cats. The aim of this work was to report an atypical case of bone sporotrichosis in a cat.Case: A 5-year-old, male, neutered, mongrel and indoor cat was present at the Veterinary Clinic Hospital, Federal University of Rio Grande do Sul (HCV-UFRGS), Porto Alegre, Brazil, with lameness and increased volume in the left hindlimb. The animal had been treated intermittently with itraconazole during the last three years due to another cutaneous lesion which was recurrent and undiagnosed. A firm and painful mass was found in tarsal region of left hindlimb, that had approximately 5 cm in diameter. Radiographic examination of the left tibial-tarsal joint revealed bone lysis in the fifth metatarsal calcaneus, in addition to periosteum proliferation in calcaneus, tibio-tarsal subluxation, presence of osteophytes in tarsal bones and increase in soft tissue volume. Histopathological analysis of the biopsied tissue showed piogranulomatous inflammation. No yeast-like structures were observed in cytopathological exam. Tissue fragments were plated and Sporothrix sp. complex growth in mycological culture (Sabouraud Cycloheximide Chloramphenicol Agar). Physiological tests (growth rate at different temperatures and assimilation of sucrose and raffinose) were conducted for the differentiation of the species of complex. Molecular identification was performed using panfungal primers (ITS3-F / ITS4-R). The diagnosis of bone sporotrichosis caused by Sporothrix brasiliensis was based on clinical signs, mycological (confirmed by isolation and identification in culture medium) and molecular methods. Treatment was based on excision of the limb associated with oral administration of itraconazole and silymarin for two months. Unfortunately, three months later new nodules were seen at the abdomen and biopsy samples were positive in a new fungal culture for Sporothrix sp. Oral treatment was then restarted for four months. The cat is now free of lesions for six months and clinical monitoring visit is usually done once per month.Discussion: Sporotrichosis is a fungal infection with worldwide distribution, mostly in tropical and subtropical countries, characterized by cutaneous and subcutaneous lesions with regional lymphocutaneous dissemination, but some pulmonary and systemic infections in human have been reported. Cats are frequently infected with sporotrichosis in Brazil and develop a scattered cutaneous condition. On the other hand, the systemic form of the disease have been more observed with a disseminated respiratory or systemic condition, including infection of the lungs, liver, spleen, kidney, testis, eyes, bones, central nervous system, gastrointestinal tract, and mammary glands may also be affected. The occurrence of bone sporotrichosis, without skin lesions, show the high susceptibility of these animals to infection by Sporothrix. Molecular methods for the differentiation of Sporothrix complex are needed when the conventional methodology (histopathology and culture) does not allow the identification of the agent. The reference standard for diagnosing sporotrichosis is microscopic characterization of the pathogen isolated in culture. In our study, although the culture was positive, PCR was necessary for detecting and identifying Sporothrix brasiliensis. The reported case of bone sporotrichosis emphasizes the importance of a conclusive and differential diagnosis in feline lytic bone lesions based on the detection of fungal in the tissue by molecular methods associated with the isolation of the agent in a fungal culture.

Sporotrichosis is a subcutaneous mycosis caused by thermodimorphic fungi of the genus Sporothrix. The phenotypic and genotypic differences of the isolates within the genus Sporothrix have been associated with their geographic distribution, virulence capacity, or clinical manifestation of sporotrichosis. Therefore, it is crucial to identify the causative agent of sporotrichosis. However, there are few case reports and studies in animals compared to those in humans, despite the substantial increase in the number of cases of sporotrichosis by zoonotic transmission, especially in endemic areas. Considering the epidemiological importance, taxonomic evolution and worldwide distribution of these fungi in the last decade, there is interest in identifying the species of the genus Sporothrix in different regions of the world. This study aimed to analyze the geographic distribution of animal sporotrichosis in the world, caused by pathogenic species identified by use of molecular tools. This systematic review of articles from 2007 to 2021 analyzed the geographic distribution of species that cause sporotrichosis in cats, dogs and other animals. It demonstrated that the most identified species were S. brasiliensis, isolated from cats in Brazil and S. schenckii isolated from cats in Malaysia. We show the lack of studies in global areas and reinforce the need to use molecular tools to identify and monitor potential pathogens.