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

Abstract

BACKGROUNDSporotrichosis 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.

Influences of the Culturing Media in the Virulence and Cell Wall of Sporothrix schenckii, Sporothrix brasiliensis, and Sporothrix globosa

“…This strategy, combined with chemical treatments or pathogen genetic manipulation, helps to unveil virulence factors and determinants and to assess their contribution to the pathogen aggressivity and resilience. In the case of the Sporothrix species, mice have been chosen as the model organism to assess virulence, and the most widely used experimental infection involves the subcutaneous administrations of fungal cells [ 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. Intraperitoneal and intravenous models have also been standardized to assess the Sporothrix virulence [ 17 , 19 , 26 , 29 , 30 , 31 ].…”

Clinical and Anatomopathological Evaluation of BALB/c Murine Models Infected with Isolates of Seven Pathogenic Sporothrix Species

“…Our research group is a pioneer in studying the infection of mice inoculated simultaneously with isolates of seven clinically important Sporothrix species in vivo and exploring the infection with S. schenckii sensu stricto and S. brasiliensis in a chemically immunosuppressed murine model [24]. Besides that, we have experience in animal models challenged with different fungal species [25][26][27][28][29].…”

Disseminated Sporotrichosis With Brain Abscesses in an HIV-Infected Patient

“…The increasing number of reports of sporotrichosis in the HIV-infected population has been postulated to represent an emerging global health concern associated with the AIDS pandemic [5]. To date, less than 300 unique cases of disseminated sporotrichosis affecting the CNS in the HIV-infected population have been published [5,6,12,[16][17][18]. According to estimates of prevalence from case studies, the true burden of disseminated sporotrichosis to the CNS in HIV-infected patients may not be adequately illustrated.…”

“…Moreira et al and Freitas et al showed that HIV-positive patients are more susceptible to disseminated forms of sporotrichosis and recommended screening and/or serial monitoring lumbar punctures for every patient with sporotrichosis and HIV. Finally, S. schenckii should be considered to be a serious opportunistic pathogen in all patients with HIV/AIDS [6,9,16]. Resuming antiretroviral therapy in HIV-positive patients diagnosed with disseminated sporotrichosis remains controversial.…”