Sporotrichosis in Rio de Janeiro,Brazil: Sporothrix brasiliensis Is Associated with Atypical Clinical Presentations

Background

There have been several recent changes in the taxonomy of Sporothrix schenckii as well as new observations regarding the clinical aspects of sporotrichosis. In this study, we determined the identification of the Sporothrix species associated with both classic and unusual clinical aspects of sporotrichosis observed in the endemic area of sporotrichosis in Rio de Janeiro, Brazil.

Methodology/Principal Findings

To verify whether S. brasiliensis is associated with clinical manifestations of sporotrichosis, a cross-sectional study was performed in which Sporothrix isolates from 50 patients with different clinical manifestations were analyzed and their isolates were studied by phenotypic and genotypic methods. Data from these patients revealed a distinct clinical picture and therapeutic response in infections caused by Sporothrix brasiliensis (n = 45) compared to patients with S. schenckii sensu stricto (n = 5). S. brasiliensis was associated with disseminated cutaneous infection without underlying disease, hypersensitivity reactions, and mucosal infection, whereas patients with S. schenckii presented with less severe and more often localized disease, similar to the majority of previously described sporotrichosis cases. Interestingly, S. brasiliensis-infected patients overall required shorter durations of itraconazole (median 16 weeks) compared to the individuals with S. schenckii (median 24 weeks).

Conclusions/Significance

These findings suggest that Sporothrix species are linked to different clinical manifestations of sporotrichosis and that S. brasiliensis is effectively treated with oral itraconazole.     

Melanins Protect Sporothrix brasiliensis and Sporothrix schenckii from the Antifungal Effects of Terbinafine

Terbinafine is a recommended therapeutic alternative for patients with sporotrichosis who cannot use itraconazole due to drug interactions or side effects. Melanins are involved in resistance to antifungal drugs and Sporothrix species produce three different types of melanin. Therefore, in this study we evaluated whether Sporothrix melanins impact the efficacy of antifungal drugs. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of two Sporothrix brasiliensis and four Sporothrix schenckii strains grown in the presence of the melanin precursors L-DOPA and L-tyrosine were similar to the MIC determined by the CLSI standard protocol for S. schenckii susceptibility to amphotericin B, ketoconazole, itraconazole or terbinafine. When MICs were determined in the presence of inhibitors to three pathways of melanin synthesis, we observed, in four strains, an increase in terbinafine susceptibility in the presence of tricyclazole, a DHN-melanin inhibitor. In addition, one S. schenckii strain grown in the presence of L-DOPA had a higher MFC value when compared to the control. Growth curves in presence of 2×MIC concentrations of terbinafine showed that pyomelanin and, to a lesser extent, eumelanin were able to protect the fungi against the fungicidal effect of this antifungal drug. Our results suggest that melanin protects the major pathogenic species of the Sporothrix complex from the effects of terbinafine and that the development of new antifungal drugs targeting melanin synthesis may improve sporotrichosis therapies.     

Interference of melanin in the susceptibility profile of Sporothrix species to amphotericin B

BackgroundThe presence of melanin in the fungal cell is a major virulence factor of the genus Sporothrix since it protects the fungal cells against the defense systems.AimsThe present study aimed to investigate the interference of melanin in the susceptibility of Sporothrix brasiliensis and Sporothrix schenckii sensu stricto to amphotericin B and itraconazole, drugs recommended as therapy for disseminated and subcutaneous sporotrichosis, respectively.MethodsYeast cells were cultivated in minimal medium with or without l-DOPA in order to induce the production of melanin. Microdilution and killing assay methods were used to determine the antifungal activity against yeast cells with different amounts of melanin.ResultsThe killing assay showed that melanization protected isolates within the S. schenckii complex from amphotericin B, particularly in the lower concentrations tested.ConclusionsStudies combining amphotericin B and inhibitors of melanin are required in order to avoid this effect.     

Disseminated sporotrichosis with immune reconstitution inflammatory syndrome in an HIV patient: Case report and review of the literature

BackgroundSporotrichosis has been occurring as outbreaks in Brazil, reaching epidemic levels in some regions. Zoonotic transmission is the main route to acquire Sporothrix.Case reportWe describe a case of disseminated sporotrichosis caused by Sporothrix brasiliensis in an HIV/AIDS patient, with the presentation of immune reconstitution inflammatory syndrome (IRIS).ConclusionsThis case reinforces that sporotrichosis should always be suspected in patients with IRIS from endemic regions, even in patients without the typical cutaneous lesions of this mycosis.     

The Use of (1–3) β-Glucan Along with Itraconazole Against Canine Refractory Sporotrichosis

Sporotrichosis, caused by the Sporothrix schenckii fungal complex, is a zoonotic mycosis distributed worldwide. Itraconazole is the treatment of choice for domestic animals although some fungal isolates have shown resistance to this drug. The objective of this study was to report, for the first time, the use of (1–3) β-glucan along with itraconazole in the treatment of a canine with sporotrichosis caused by Sporothrix brasiliensis. The animal had ulcerated and crusted lesions, especially on the nasal planum. Clinical samples were collected for a complete blood count, cytological analysis of the lesion, and fungal culture. Based on the results of the laboratory examination, and after the fungal culture, antibiotic therapy and treatment with itraconazole were initiated. Two additional fungal cultures were performed, which were positive. After 7 months of the animal treatment with itraconazole, the S. brasiliensis culture was still positive, so that the itraconazole was associated with (1–3) β-glucan. After four weekly applications of glucan, the complete elimination of the fungus was observed based on the fungal culture negative results. The results show, therefore, that (1–3) β-glucan with itraconazole promoted the case resolution, and it may be considered a promising alternative for the treatment of sporotrichosis in cases of resistance to conventional therapy.     

Biosynthesis and Functions of a Melanoid Pigment Produced by Species of the Sporothrix Complex in the Presence of l-Tyrosine

Sporothrix schenckii is the etiological agent of sporotrichosis, the main subcutaneous mycosis in Latin America. Melanin is an important virulence factor of S. schenckii, which produces dihydroxynaphthalene melanin (DHN-melanin) in conidia and yeast cells. Additionally, l-dihydroxyphenylalanine (l-DOPA) can be used to enhance melanin production on these structures as well as on hyphae. Some fungi are able to synthesize another type of melanoid pigment, called pyomelanin, as a result of tyrosine catabolism. Since there is no information about tyrosine catabolism in Sporothrix spp., we cultured 73 strains, including representatives of newly described Sporothrix species of medical interest, such as S. brasiliensis, S. schenckii, and S. globosa, in minimal medium with tyrosine. All strains but one were able to produce a melanoid pigment with a negative charge in this culture medium after 9 days of incubation. An S. schenckii DHN-melanin mutant strain also produced pigment in the presence of tyrosine. Further analysis showed that pigment production occurs in both the filamentous and yeast phases, and pigment accumulates in supernatants during stationary-phase growth. Notably, sulcotrione inhibits pigment production. Melanin ghosts of wild-type and DHN mutant strains obtained when the fungus was cultured with tyrosine were similar to melanin ghosts yielded in the absence of the precursor, indicating that this melanin does not polymerize on the fungal cell wall. However, pyomelanin-producing fungal cells were more resistant to nitrogen-derived oxidants and to UV light. In conclusion, at least three species of the Sporothrix complex are able to produce pyomelanin in the presence of tyrosine, and this pigment might be involved in virulence.     

Two cases of sporotrichosis of the right upper extremity in right-handed patients with diabetes mellitus

BackgroundSporothrix species have proved to show high degrees of endemicity. Sporothrix globosa is the only pathogenic Sporothrix species that has till date been reported from China, where it is endemic in the northeastern provinces.AimsWe report two cases of lymphocutaneous sporotrichosis with diabetes mellitus as underlying disease in patients from the non-endemic area of China.MethodsA 59-year-old farmer and a 60-year-old gardener were admitted in February and June 2014, respectively. Both patients were right-handed men and presented with progressive plaques and nodules, which they had for several years, involving the right upper extremity. Skin biopsy from the granuloma was taken and cultured on Sabouraud medium, and molecular identification based on the calmodulin region was performed. Antifungal susceptibility testing was also performed with the microdilution method.ResultsBiopsy of the lesions showed the presence of infectious granuloma. The fungal cultures were identified as Sporothrix globosa by conventional methods, and confirmed by molecular identification. A subsequent course of oral antifungal therapy with low dosage of itraconazole was well tolerated and resolved the infection.ConclusionsIdentification of fungal species and antifungal susceptibility testing are mandatory for epidemiological and therapeutic reasons. Early diagnosis of sporotrichosis is essential to prevent those sequelae when the disease progresses and provides highly effective methods for treating this emerging disease. Avoiding the exposure to plant material potentially contaminated with fungal spores should be recommended, especially in immunocompromised patients.     

Sporotrichosis After Tattooing Caused by Sporothrix brasiliensis

Sporotrichosis is a subcutaneous mycosis caused by pathogenic species of the genus Sporothrix. Since 1998, the number of cases of sporotrichosis due to Sporothrix brasiliensis has grown significantly in Rio de Janeiro, Brazil. Nearly all cases are related to cats as the main source of fungal infection. We report two cases of sporotrichosis following tattoos, a transmission form of S. brasiliensis not yet reported. The first patient, a 22-year-old female, had cutaneous sporotrichosis, fixed form, over a tattoo in her lumbar region. The lesion appeared 12 weeks after she was tattooed. The second patient, a 27-year-old female, had a lymphocutaneous sporotrichosis over a forearm tattoo. The lesion appeared two weeks after she was tattooed. In both cases there was no history of contact with cats or other plausible source of infection. The present study highlights that other non-zoonotic forms of transmission of S. brasiliensis may occur in endemic areas.

     

Proteomics-Based Characterization of the Humoral Immune Response in Sporotrichosis: Toward Discovery of Potential Diagnostic and Vaccine Antigens

Background

Sporothrix schenckii and associated species are agents of human and animal sporotrichosis that cause large sapronoses and zoonoses worldwide. Epidemiological surveillance has highlighted an overwhelming occurrence of the highly pathogenic fungus Sporothrix brasiliensis during feline outbreaks, leading to massive transmissions to humans. Early diagnosis of feline sporotrichosis by demonstrating the presence of a surrogate marker of infection can have a key role for selecting appropriate disease control measures and minimizing zoonotic transmission to humans.

Methodology

We explored the presence and diversity of serum antibodies (IgG) specific against Sporothrix antigens in cats with sporotrichosis and evaluated the utility of these antibodies for serodiagnosis. Antigen profiling included protein extracts from the closest known relatives S. brasiliensis and S. schenckii. Enzyme-linked immunosorbent assays and immunoblotting enabled us to characterize the major antigens of feline sporotrichosis from sera from cats with sporotrichosis (n = 49), healthy cats (n = 19), and cats with other diseases (n = 20).

Principal Findings

Enzyme-linked immunosorbent assay-based quantitation of anti-Sporothrix IgG exhibited high sensitivity and specificity in cats with sporotrichosis (area under the curve, 1.0; 95% confidence interval, 0.94–1; P<0.0001) versus controls. The two sets of Sporothrix antigens were remarkably cross-reactive, supporting the hypothesis that antigenic epitopes may be conserved among closely related agents. One-dimensional immunoblotting indicated that 3-carboxymuconate cyclase (a 60-kDa protein in S. brasiliensis and a 70-kDa protein in S. schenckii) is the immunodominant antigen in feline sporotrichosis. Two-dimensional immunoblotting revealed six IgG-reactive isoforms of gp60 in the S. brasiliensis proteome, similar to the humoral response found in human sporotrichosis.

Conclusions

A convergent IgG-response in various hosts (mice, cats, and humans) has important implications for our understanding of the coevolution of Sporothrix and its warm-blooded hosts. We propose that 3-carboxymuconate cyclase has potential for the serological diagnosis of sporotrichosis and as target for the development of an effective multi-species vaccine against sporotrichosis in animals and humans.     

Sporotrichosis Treatment: Overview and Update

Sporotrichosis, caused by several species from the genus Sporothrix, mainly affects men working in agricultural labor. It is reported mostly from endemic regions located in tropical and subtropical areas. Sporotrichosis usually affects subcutaneous tissue with no symptoms or mild symptoms, but it causes disseminated and even fatal disease if the patient is immunocompromised. Significant progress in the knowledge of etiologic agents of sporotrichosis has been achieved recently, but evaluations of treatment using well-designed clinical trials have been neglected. This article reviews the drugs currently used to treat subcutaneous disease, describing the differences in their efficacy, and reviews recent findings about the proposed new Sporothrix species of clinical interest, as well as the role of melanin as a virulence factor in Sporothrix schenckii.     

Differences in virulence between isolates of feline Sporotrichosis

Sporotrichosis is a chronic subcutaneous mycosis caused by Sporothrix schenckii. This work aimed to evaluate the virulence of two different isolates of S. schenckii from cutaneous (CUT) and systemic (SYS) forms of feline sporotrichosis. A standard inoculum with 2 × 10³ yeast cells/ml was prepared from each of the isolates. The experimental infection was carried out with 0.1 ml of the inoculum from both isolates and then injected in the paw pads of Swiss albino mice of groups CUT and SYS. The clinical evolution of the disease and the diameter of the lesion at the inoculated sites were evaluated during nine weeks. Four necropsies were done to collect material from the lesions (p < 0.01). Group CUT demonstrated a more evident clinical evolution of the disease from week two to week five; large lesions in the paw pad on week four (p < 0.01); and a higher incidence of lesions in other parts of the body (p < 0.01) than group SYS (p < 0.01). S. schenckii was isolated from the inoculated site in groups SYS and CUT until days 30 and 45, respectively. Granulomas with yeast cells usually localized in the central area were observed in histopathology sections on days 15 and 30 post-inoculations. Those yeast cells decreased on day 45 being absent on day 62 when tissue repair initiated. The results showed that distinct clinical isolates of S. schenckii cause significant differences in the clinical evolution of sporotrichosis.     

Asexual Propagation of a Virulent Clone Complex in a Human and Feline Outbreak of Sporotrichosis

Sporotrichosis is one of the most frequent subcutaneous fungal infections in humans and animals caused by members of the plant-associated, dimorphic genus Sporothrix. Three of the four medically important Sporothrix species found in Brazil have been considered asexual as no sexual stage has ever been reported in Sporothrix schenckii, Sporothrix brasiliensis, or Sporothrix globosa. We have identified the mating type (MAT) loci in the S. schenckii (strain 1099-18/ATCC MYA-4821) and S. brasiliensis (strain 5110/ATCC MYA-4823) genomes by using comparative genomic approaches to determine the mating type ratio in these pathogen populations. Our analysis revealed the presence of a MAT1-1 locus in S. schenckii while a MAT1-2 locus was found in S. brasiliensis representing genomic synteny to other Sordariomycetes. Furthermore, the components of the mitogen-activated protein kinase (MAPK)-pheromone pathway, pheromone processing enzymes, and meiotic regulators have also been identified in the two pathogens, suggesting the potential for sexual reproduction. The ratio of MAT1-1 to MAT1-2 was not significantly different from 1:1 for all three Sporothrix species, but the population of S. brasiliensis in the outbreaks originated from a single mating type. We also explored the population genetic structure of these pathogens using sequence data of two loci to improve our knowledge of the pattern of geographic distribution, genetic variation, and virulence phenotypes. Population genetics data showed significant population differentiation and clonality with a low level of haplotype diversity in S. brasiliensis isolates from different regions of sporotrichosis outbreaks in Brazil. In contrast, S. schenckii isolates demonstrated a high degree of genetic variability without significant geographic differentiation, indicating the presence of recombination. This study demonstrated that two species causing the same disease have contrasting reproductive strategies and genetic variability patterns.     

Functional,genetic and bioinformatic characterization of a calcium/calmodulin kinase gene in <Emphasis Type="Italic">Sporothrix schenckii</Emphasis>

Background  

Sporothrix schenckiiis a pathogenic, dimorphic fungus, the etiological agent of sporotrichosis, a subcutaneous lymphatic mycosis. Dimorphism inS. schenckiiresponds to second messengers such as cAMP and calcium, suggesting the possible involvement of a calcium/calmodulin kinase in its regulation. In this study we describe a novel calcium/calmodulin-dependent protein kinase gene inS. schenckii, sscmk1, and the effects of inhibitors of calmodulin and calcium/calmodulin kinases on the yeast to mycelium transition and the yeast cell cycle.     

Phenotypic and Molecular Identification of <Emphasis Type="Italic">Sporothrix</Emphasis> Isolates from an Epidemic Area of Sporotrichosis in Brazil

Sporotrichosis has significantly increased in Brazil in the last decade, particularly in the state of Rio de Janeiro, with the occurrence of an epidemic related to zoonotic transmission from cats to humans. Recently, four new phylogenetic species were incorporated into the Sporothrix species complex based on the phenotypic and molecular characteristics, and a new species name (Sporothrix brasiliensis) was proposed for some of the Sporothrix isolates from this epidemic. This study describes the characterization of 246 isolates obtained from patients attending the Laboratory of Infectious Dermatology, IPEC-FIOCRUZ, between 1998 and 2008, together with one environmental sample. Two hundred and six of the isolates (83.4%) were characterized as S. brasiliensis, 15 (6.0%) as S. schenckii, and one (0.5%) as S. mexicana. Twenty-five isolates (10.1%) could not be identified according to their phenotype and were classified as Sporothrix spp. The calmodulin gene was sequenced to confirm the identity of these isolates. The molecular analysis demonstrated that 24 of the isolates were S. brasiliensis, with the remainder being a S. globosa isolate. The isolate characterized phenotypically as S. mexicana was clustered on the S. schenckii clade. The correlation between molecular data and phenotypic characteristics described in this study is fundamental to the identification of the Sporothrix complex.     

Lymphocutaneous and nasal sporotrichosis in a dog from Southern Italy: Case Report

Sporotrichosis is a chronic, granulomatous and usually lymphocutaneous infection of humans and animals caused by the dimorphic fungus, Sporothrix schenckii. This study reports a case of lymphocutaneous and nasal sporotrichosis in a hunting dog with a three month history of non-healing skin lesions. Cytological examination of nasal discharge and of the material collected from ulcerated skin surfaces showed a few cigar-shaped organisms within macrophages. Fungal cultures of nasal and ulcerated skin swabs yielded colonies of S. schenckii. The dog received oral itraconazole but died of unrelated causes. Necropsic examination was not performed.     

Differences in Cell Morphometry,Cell Wall Topography and Gp70 Expression Correlate with the Virulence of Sporothrix brasiliensis Clinical Isolates

Sporotrichosis is a chronic infectious disease affecting both humans and animals. For many years, this subcutaneous mycosis had been attributed to a single etiological agent; however, it is now known that this taxon consists of a complex of at least four pathogenic species, including Sporothrix schenckii and Sporothrix brasiliensis. Gp70 was previously shown to be an important antigen and adhesin expressed on the fungal cell surface and may have a key role in immunomodulation and host response. The aim of this work was to study the virulence, morphometry, cell surface topology and gp70 expression of clinical isolates of S. brasiliensis compared with two reference strains of S. schenckii. Several clinical isolates related to severe human cases or associated with the Brazilian zoonotic outbreak of sporotrichosis were genotyped and clustered as S. brasiliensis. Interestingly, in a murine subcutaneous model of sporotrichosis, these isolates showed a higher virulence profile compared with S. schenckii. A single S. brasiliensis isolate from an HIV-positive patient not only showed lower virulence but also presented differences in cell morphometry, cell wall topography and abundant gp70 expression compared with the virulent isolates. In contrast, the highly virulent S. brasiliensis isolates showed reduced levels of cell wall gp70. These observations were confirmed by the topographical location of the gp70 antigen using immunoelectromicroscopy in both species. In addition, the gp70 molecule was sequenced and identified using mass spectrometry, and the sequenced peptides were aligned into predicted proteins using Blastp with the S. schenckii and S. brasiliensis genomes.     

Squamous cell carcinoma subsequent to scarring caused by sporotrichosis: A case report

BackgroundSporotrichosis is a fungal disease caused by the Sporothrix schenckii species complex. It is usually acquired by trauma with plants. Lymphatic-cutaneous is the most common clinical manifestation.Case reportThe present case describes the development of an epidermoid carcinoma as a late complication on a long evolution sporotrichosis scar. During a period of 50 years, the patient had lesions in the right hand. Sporotrichosis was diagnosed and treated with potassium iodide. Eleven years after the healing of the lesions, a squamous cell carcinoma on the scar of this mycosis was diagnosed.ConclusionsThe chronic sporotrichosis injury was probably the cause of the tumor developed on the scar.