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.

Sporothrix schenckii and sporotrichosis

Durante muito tempo a esporotricose foi descrita como uma doença de baixa incidência no Brasil, no entanto, relatos recentes mostram que não só o número de casos descritos vem aumentando como a incidência de formas clínicas mais graves ou atípicas da doença vem ocorrendo com maior frequência. Dados recentes apontam que este grupo clínico já constitui cerca de 10% dos casos de esporotricose com diagnóstico confirmado. Apresentações clínicas mais raras, principalmente a esporotricose osteoarticular, podem estar associadas tanto a quadros de imunodepressão do paciente quanto à transmissão zoonótica desta doença. O diagnóstico da forma extracutânea ou de formas atípicas é um desafio que tem como ferramenta auxiliar o desenvolvimento recente de um teste sorológico para o diagnóstico das diferentes formas clínicas da esporotricose.

Sporothrix schenckii and sporotrichosis.

For a long time sporotrichosis has been regarded to have a low incidence in Brazil; however, recent studies demonstrate that not only the number of reported cases but also the incidence of more severe or atypical clinical forms of the disease are increasing. Recent data indicate that these more severe forms occur in about 10% of patients with confirmed diagnosis. The less frequent forms, mainly osteoarticular sporotrichosis, might be associated both with patient immunodepression and zoonotic transmission of the disease. The extracutaneous form and the atypical forms are a challenge to a newly developed serological test, introduced as an auxiliary tool for the diagnosis of unusual clinical forms of sporotrichosis.