Abstract
Several species in the genus Cryptococcus are facultative intracellular pathogens capable of causing disease associated with high mortality and morbidity in humans. These fungi interact with other organisms in the soil, and these interactions may contribute to the development of adaptation mechanisms that function in virulence by promoting fungal survival in animal hosts. Fungal adhesion molecules, also known as adhesins, have been classically considered as cell-surface or secreted proteins that play critical roles in microbial pathogenesis or in biofilm formation as structural components. Pathogenic Cryptococcus spp. differ from other pathogenic yeasts in having a polysaccharide capsule that covers the cell wall surface and precludes interactions of those structures with host cell receptors. Hence, pathogenic Cryptococcus spp. use unconventional tools for surface attachment. In this essay, we review the unique traits and mechanisms favoring adhesion of Cryptococcus spp. to biotic and abiotic surfaces. Knowledge of the traits that mediate adherence could be exploited in the development of therapeutic, biomedical, and/or industrial products.
Highlights
Fungi are often referred as to the “Forgotten Kingdom” because they seem to be an afterthought when people consider pathogenic microbes and focus primarily on viruses, bacteria, and parasites, and yet they are among the most abundant organisms on Earth, representing a critically important group of organisms in the biota of the planet [1]
The genus Cryptococcus includes about 30 species found ubiquitously in the environment, but two species complexes, C. neoformans and C. gattii cause most human disease [3]
Other studies demonstrated that C. neoformans invasion of brain endothelial cells required the specific interaction between hyaluronic acid on the fungal surface and CD44-containing lipid rafts expressed by human brain microvascular endothelial cells (HBMEC)
Summary
Fungi are often referred as to the “Forgotten Kingdom” because they seem to be an afterthought when people consider pathogenic microbes and focus primarily on viruses, bacteria, and parasites, and yet they are among the most abundant organisms on Earth, representing a critically important group of organisms in the biota of the planet [1]. Molecular evolutionary studies revealed that C. neoformans and C. gattii diverged from a common environmental ancestor as recently as 30–40 million year ago [12,13], or as long as 100 million year ago [14] Given that these species emerged in Africa and South America, respectively, and that the older date correlates with the breakup of the supercontinent Pangea, continental drift has been proposed as the initiating mechanism for speciation [14]. Unlike many other human pathogens, Cryptococcus spp. require no animal host to survive and complete their life cycle These fungi interact with free-living amoeba and soil nematodes, which could pose a selective force for fungal factors that are serendipitously advantageous for survival in mammals. C. neoformans and C. gattii are facultative intracellular pathogens that have evolved sophisticated strategies for virulence in a broad host range Their extraordinary ability to survive harsh and fluctuating conditions in vivo could be explained by adaptations to the ecology at the source of infection [24]. To describe the emergence of a new trait function not immediately beneficial [25], has been described as “ready-made”, “accidental”, or “stochastic” virulence [26,27], which posits that the pathogenic potential of these fungi is a consequence of adaptation to their normal ecological niche
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
