Adhesins in Candida glabrata.

Bea Timmermans,Patrick Van Dijck,Alejandro De Las Peñas,Irene Castaño

doi:10.3390/jof4020060

Abstract

The human fungal pathogen Candida glabrata is causing more and more problems in hospitals, as this species shows an intrinsic antifungal drug resistance or rapidly becomes resistant when challenged with antifungals. C. glabrata only grows in the yeast form, so it is lacking a yeast-to-hyphae switch, which is one of the main virulence factors of C. albicans. An important virulence factor of C. glabrata is its capacity to strongly adhere to many different substrates. To achieve this, C. glabrata expresses a large number of adhesin-encoding genes and genome comparisons with closely related species, including the non-pathogenic S. cerevisiae, which revealed a correlation between the number of adhesin-encoding genes and pathogenicity. The adhesins are involved in the first steps during an infection; they are the first point of contact with the host. For several of these adhesins, their importance in adherence to different substrates and subsequent biofilm formation was demonstrated in vitro or in vivo. In this review, we provide an overview of the role of C. glabrata adhesins during adhesion and biofilm formation both, under in vitro and in vivo conditions.

Highlights

Candida species pose a major problem in hospitals, as they are the most frequently isolated fungal microorganisms in Healthcare-Associated Infections (HAI) [1,2,3,4]
The new genome comparisons of the Nakaseomyces species could expose new or confirm already identified factors important for pathogenesis. The latter is true, since Gabaldón and co-workers found a correlation between the number of EPA genes (Epithelial adhesin), the largest family of C. glabrata adhesins, and pathogenicity in the Nakaseomyces clade: the pathogenic C. bracarensis and C. nivariensis encode for 12 and 9 EPA adhesins, respectively, while only one EPA adhesin was found in the non-pathogenic Nakaseomyces delphensis [26]
It is known that C. glabrata encodes for a high number of adhesins, which are considered as one of the main virulence factors of this pathogen

Summary

Introduction

Candida species pose a major problem in hospitals, as they are the most frequently isolated fungal microorganisms in Healthcare-Associated Infections (HAI) [1,2,3,4]. The new genome comparisons of the Nakaseomyces species could expose new or confirm already identified factors important for pathogenesis The latter is true, since Gabaldón and co-workers found a correlation between the number of EPA genes (Epithelial adhesin), the largest family of C. glabrata adhesins, and pathogenicity in the Nakaseomyces clade: the pathogenic C. bracarensis and C. nivariensis encode for 12 and 9 EPA adhesins, respectively, while only one EPA adhesin was found in the non-pathogenic Nakaseomyces delphensis [26]. This underscores that adhesins are important for the pathogenicity of fungal species. Glabrata clinical isolates and identification of their adhesin-like genes, followed by in-depth expression analysis and functional characterisation, could further increase our knowledge about the mechanism of pathogenesis in C. glabrata

Adhesin Families and Ligand Binding Specificity

Surface Hydrophobicity and Adherence

Adherence to Substrates and Biofilm Formation

Concluding Remarks

Findings

Methods