Comparison of Cell Wall Polysaccharide Composition and Structure Between Strains of Sporothrix schenckii and Sporothrix brasiliensis.

Héctor L Villalobos-Duno,Héctor M Mora-Montes,Bernardo Franco,Nancy E Lozoya-Pérez,Leila M Lopes-Bezerra,Laura A Barreto,Álvaro Alvarez-Aular,Gustavo A Niño-Vega

doi:10.3389/fmicb.2021.726958

Abstract

Sporothrix schenckii, Sporothrix brasiliensis, and Sporothrix globosa are the main causative agents of sporotrichosis, a human subcutaneous mycosis. Differences in virulence patterns are associated with each species but remain largely uncharacterized. The S. schenckii and S. brasiliensis cell wall composition and virulence are influenced by the culturing media, with little or no influence on S. globosa. By keeping constant the culturing media, we compared the cell wall composition of three S. schenckii and two S. brasiliensis strains, previously described as presenting different virulence levels on a murine model of infection. The cell wall composition of the five Sporothrix spp. strains correlated with the biochemical composition of the cell wall previously reported for the species. However, the rhamnose-to-β-glucan ratio exhibits differences among strains, with an increase in cell wall rhamnose-to-β-glucan ratio as their virulence increased. This relationship can be expressed mathematically, which could be an important tool for the determination of virulence in Sporothrix spp. Also, structural differences in rhamnomannan were found, with longer side chains present in strains with lower virulence reported for both species here studied, adding insight to the importance of this polysaccharide in the pathogenic process of these fungi.

Highlights

Sporotrichosis, a cutaneous and subcutaneous mycosis of humans and other mammals, is caused by species described within the pathogenic clade of the Sporothrix genus, of which S. brasiliensis, S. schenckii, and S. globosa are the three species of major clinical importance
The cell wall is the first point of contact with the host upon infection and colonization; understanding its composition allow unveiling specific mechanisms triggered by pathogen-associated molecular patterns (PAMP) and their corresponding pathogen recognition receptor (PRR) (Gow et al, 2017)
It was reported that carbon or nitrogen limitation during growth of yeast cells of S. brasiliensis and S. schenckii resulted in a reduced virulence, and the mechanism is related to affect the cell wall composition, where an increase in cell wall β-glucan, and a reduction of rhamnose and mannose was observed (LozoyaPérez et al, 2020)

Summary

Introduction

Sporotrichosis, a cutaneous and subcutaneous mycosis of humans and other mammals, is caused by species described within the pathogenic clade of the Sporothrix genus, of which S. brasiliensis, S. schenckii, and S. globosa are the three species of major clinical importance (de Beer et al, 2016). The disease is characterized by cutaneous and subcutaneous lesions with regional lymphocutaneous dissemination, some pulmonary and systemic infections have been reported (Callens et al, 2006). It is a neglected infectious disease with a worldwide distribution, and a higher incidence in tropical and subtropical countries (Barros et al, 2011; Chakrabarti et al, 2014). Multiple infections might arise from a single source, which can lead to outbreaks (Chakrabarti et al, 2014)

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