A case of sporotrichosis caused by different Sporothrix brasiliensis strains: mycological, molecular, and virulence analyses.

BACKGROUND: Sporotrichosis is a subcutaneous mycosis caused by dimorphic pathogenic fungi belonging to the Sporothrix genus. Pathogenic Sporothrix species typically produce melanin, which is known to be a virulence factor. OBJECTIVES: The aim of this study was to perform phenotypic, genotypic, and virulence analyses of two distinct Sporothrix brasiliensis strains isolated from the same lesion on a patient from Rio de Janeiro. METHODS AND FINDINGS: Genotypic analyses by partial sequencing of the calmodulin, ß-tubulin, and chitin synthase genes, as well as polymerase chain reaction (PCR)-fingerprinting by T3B, M13, and GACA, showed that the isolates were very similar but not identical. Both isolates had similar phenotypic characteristics and effectively produced melanin in their yeast forms, accounting for their ability of causing disease in a murine sporotrichosis model. Remarkably, isolate B was albino in its environmental form but caused more severe disease than the pigmented A isolate. CONCLUSIONS: These findings indicate that the patient was infected by two genetically and biologically distinct S. brasiliensis that vary in their production of melanin in their environmental forms. The results underscore the importance of characterizing phenotypically different isolates found in the same clinical specimen or patient.

A case of sporotrichosis caused by different Sporothrix brasiliensis strains: mycological, molecular, and virulence analyses

BACKGROUND Sporotrichosis is a subcutaneous mycosis caused by dimorphic pathogenic fungi belonging to the Sporothrix genus. Pathogenic Sporothrix species typically produce melanin, which is known to be a virulence factor. OBJECTIVES The aim of this study was to perform phenotypic, genotypic, and virulence analyses of two distinct Sporothrix brasiliensis strains isolated from the same lesion on a patient from Rio de Janeiro. METHODS AND FINDINGS Genotypic analyses by partial sequencing of the calmodulin, β-tubulin, and chitin synthase genes, as well as polymerase chain reaction (PCR)-fingerprinting by T3B, M13, and GACA, showed that the isolates were very similar but not identical. Both isolates had similar phenotypic characteristics and effectively produced melanin in their yeast forms, accounting for their ability of causing disease in a murine sporotrichosis model. Remarkably, isolate B was albino in its environmental form but caused more severe disease than the pigmented A isolate. CONCLUSIONS These findings indicate that the patient was infected by two genetically and biologically distinct S. brasiliensis that vary in their production of melanin in their environmental forms. The results underscore the importance of characterizing phenotypically different isolates found in the same clinical specimen or patient.

Sporotrichosis in HIV-infected patients: report of 21 cases of endemic sporotrichosis in Rio de Janeiro, Brazil.

Sporotrichosis is endemic in Rio de Janeiro, Brazil, and cases have been reported to be associated with HIV. This article describes the clinical manifestations and evolution of sporotrichosis in HIV-positive patients and constitutes the largest case series reported to date. There were 21 HIV-positive patients with sporotrichosis diagnosed by the recovery of the etiologic agent from 1999-2009. Sixteen patients (76.2%) were men and five (23.8%) were women, with a mean age of 41.2 years. Seven of these individuals were previously unaware of their HIV infection. Mean CD4 count was 346.4 cells/µl. The most frequent clinical presentations of sporotrichosis in these patients were the lymphocutaneous and disseminated form (seven patients each, 33.3%), followed by the widespread cutaneous form in five (23.8%), and fixed form in the remaining two (9.5%). In patients with the disseminated forms, clinical manifestations involved the skin in six, mucosa (nasal, oral, or conjunctival) in four, bone in two, and meninges in two. Eleven (52.4%) patients received itraconazole and eight (38.1%) amphotericin B contributing to an overall cure rate of 81%. Spontaneous cure was observed in one patient. The clinical forms of sporotrichosis varied according to the patients' immune status. The results demonstrate the importance of sporotrichosis as an opportunistic infection associated with AIDS in countries where the mycosis occurs.

Estudo da virulência, adesão e características fenotípicas de isolados do complexo Sporothrix / Study of virulence, adhesion and phenotypic characteristics of isolates of Sporothrix complex

A esporotricose é uma doença micótica, infecciosa e crônica, que envolve o tecido cutâneo e subcutâneo, e que pode afetar seres humanos e animais. Esta micose sempre foi atribuída a um único patógeno, o Sporothrix schenckii, um fundo termodimórfico, que cresce como levedura a 37 oC e como micélio à temperatura ambiente. No entanto, nos últimos anos, foi demonstrado que isolados identificados como S. schenckii apresentavam grande variabilidade genética, sugerindo que esta táxon consiste em um complexo de espécies. Esta doença é causada pela implantação traumática do patógeno fúngico, porém os mecanismos de invasão e disseminação deste microorganismo, bem como as moléculas envolvidas nestes processos, ainda são pouco conhecidos. Com base nessas informações, este trabalho visa identificar moléculas de superfície deste patógeno envolvidas na interação deste fungo com proteínas matriciais, bem como analisar diferenças fenotípicas entre espécies do denominado complexo Sporothrix. Foram utilizados, neste estudo, cinco isolados de Sporothrix spp., sendo três isolados clínicos, um isolado ambiental e um isolado de gato. A virulência de cada isolado foi comparada à capacidade adesiva à proteína matricial fibronectina. Foi observado que os isolados com amior capacidade infectiva eram os que apresentavam maior capacidade adesiva à fibronectina. Verificamos então a expressão de adesinas para fibronectina na superfície de cada isolado, por Western blot, e observamos que os isolados mais virulentos e com maior capacidade adesiva expressavam mais adesinas para fibronectina. Bandas reativas com o anticorpo monoclonal contra adesina gp70 (mAb P6E7) foram reveladas nos extratos de parede celular dos isolados estudados. Análises por microscopia confocal revelaram a colocalização da gp70 com a adesina para fibronectina na superfície dos isolados. Análises filogenéticas demonstraram que os isolados estudados possuíam diferenças genotípicas capazes de agrupá-los em duas espécies...

Sporotrichosis is a chronic and infectious diseases that involves the cutaneous and subcutaneous tissue, which can affect humans and animals. This mycosis has always been attributed to a single pathogen, the Sporothrix schenckii, a dimorphic fungus, that grows as yeast at 37 oC and as mycelia at room temperature. However, in recent years, some isolates identifies as S. schenckii showed considerable genetic variability, sugesting that this taxon consists of a complex of species. This disease is caused by the traumatic inoculation of the fungal pathogen, however, the molecules involved in the invasion and dissemination of this microorganism are still poorly understood. The aim of this study is to identify surface molecules involved in the interaction of this fungus with extracellular matrix proteins and to examine phenotypic differences between species in the Sporothrix complex. Five isolates were used throughout this study, three clinical isolates, an environmental and one cat isolate. The virulence of each isolate was compared to the adhesive capacity to fibronectin. We observed that the most virulent isolates exhibited the higher capacity to interact with fibronectin. The expression of adhesins for fibronectin on the surface of each isolate was verified by Western blot. This analysis showed that the most virulent isolates expressed more fibronectin adhesins than the avirulent ones. Positive bands for the monoclonal antibody raised against gp70 adhesin (mAb P6E7) were revealed in cell wall extracts of the isolates studied. Confocal microscopy confirmed the colocalization of fibronectin and mAb P6E7 on the yeast cell surface. Molecular analysis showed genotypic differences between isolates used in this study, that can cluster than them into two species, S. schenckii and S. brasiliensis. This phylogenetic analysis revealed that the avirulent isolate was S. brasiliensis and not S. schenckii as previously thought. This new data led us o determine whether...

Relationships among genotypes, virulence and clinical forms of Sporothrix schenckii infection.

This study explored the relationships among genotypes, virulence and clinical forms of Sporothrix schenckii. Genomic DNA from isolates of S. schenckii, collected from different clinical forms of sporotrichosis, was amplified by randomly amplified polymorphic DNA (RAPD). Suspensions of different isolates of S. schenckii were inoculated into healthy BALB/c mice to compare their virulence, and the numbers and distribution of spores were determined by histological analysis. RAPD analysis indicated that the isolates from different clinical forms of sporotrichosis belonged to different genotypes. The mice inoculated with isolates from disseminated sporotrichosis showed an earlier onset of illness and more severe lesions than those inoculated with isolates from lymphocutaneous sporotrichosis, which, in turn, showed an earlier onset of illness and more severe lesions than those inoculated with isolates from fixed cutaneous sporotrichosis. Healthy BALB/c mice injected with isolates from disseminated sporotrichosis died within 10 days, whereas isolates from lymphocutaneous sporotrichosis and fixed cutaneous sporotrichosis failed to cause death. Histologically, mice inoculated with isolates from disseminated sporotrichosis had more spores than those inoculated with isolates from lymphocutaneous sporotrichosis and fixed cutaneous sporotrichosis. Thus, different genotypes may be associated closely with the virulence of different clinical forms of S. schenckii infection.