Candida biofilms

Abstract

In response to attachment to a surface, fungal cells produce biofilms, three-dimensional structures composed of cells surrounded by exopolymeric matrices. Surface attachment causes Candida albicans cells to enter a special physiological state in which they are highly resistant to antifungal drugs and express the drug efflux determinants CDR1, CDR2 and MDR1. C. albicans biofilms produced under different conditions differ in their cellular morphology and matrix content, which suggests that biofilms formed within a host, for example on indwelling medical devices, would also differ depending on the nature of the device and its location. The mechanisms by which surface attachment leads to biofilm formation are presently not understood.

Candida biofilm formation on voice prostheses

“…Similar observations were made by Ramage et al (2001). Mature Candida biofilms exhibit a complex three-dimensional structure and display extensive spatial heterogeneity (Chandra et al, 2001;Hawser & Douglas, 1994;Hawser et al, 1998;Kumamoto, 2002). This structural complexity is thought to represent the optimal spatial arrangement to facilitate the influx of nutrients, the disposal of waste products, and the establishment of micro-niches throughout the biofilm.…”

Phenotype switching affects biofilm formation by Candida parapsilosis

“…In yeast, the most detailed descriptions of biofilm structure come from studies on Candida albicans (Baillie & Douglas, 1999; Chandra et al, 2001;Hawser & Douglas, 1994;Kumamoto, 2002;Shin et al, 2002). In general, a layer of cells in the yeast form is found attached to the surface, with a layer of filamentous cells above, surrounded by an exopolymeric matrix (Kumamoto, 2002). Cells in biofilms are associated with a specific geneexpression pattern, including the overexpression of amino acid biosynthetic genes, particularly those for amino acids containing sulfur (García-Sánchez et al, 2004).…”

Mechanisms of Antifungal Drug Resistance

“…Biofilms are one of the most prevalent forms of microbial growth in nature, and Candida species are among the most common etiologic agents of biofilm infections (Kumamoto 2002;Ramage et al 2009), although other yeasts and filamentous fungi are important biofilm producers as well (Ramage et al 2009). Biofilms display an organized three-dimensional structure comprised of a dense network of yeast and filamentous cells embedded in an exopolymeric matrix consisting of carbohydrates, proteins, and nucleic acids.…”

“…The matrix is a major feature that distinguishes biofilms from planktonic cells. Candida biofilms are intrinsically resistant to azoles, and the mechanisms are multifactorial, involving induction of drug efflux transporters and drug sequestration within the extensive matrix structure (Kumamoto 2002;Mukherjee et al 2003;Chandra et al 2005;Ramage et al 2009;Fanning and Mitchell 2012). As with planktonic C. albicans, active drug efflux can be induced by up-regulation of CDR and MDR genes (Ramage et al 2002;Mukherjee et al 2003).…”