Oral Colonization By Candida Albicans

Abstract

Candida albicans is a commensal yeast normally present in small numbers in the oral flora of a large proportion of humans. Colonization of the oral cavity by C. albicans involves the acquisition and maintenance of a stable yeast population. Micro-organisms are continually being removed from the oral cavity by host clearance mechanisms, and so, in order to survive and inhabit this eco-system, C. albicans cells have to adhere and replicate. The oral cavity presents many niches for C. albicans colonization, and the yeast is able to adhere to a plethora of ligands. These include epithelial and bacterial cell-surface molecules, extracellular matrix proteins, and dental acrylic. In addition, saliva molecules, including basic proline-rich proteins, adsorbed to many oral surfaces promote C. albicans adherence. Several adhesins present in the C. albicans cell wall have now been partially characterized. Adherence involves lectin, protein-protein, and hydrophobic interactions. As C. albicans cells evade host defenses and colonize new environments by penetrating tissues, they are exposed to new adherence receptors and respond by expressing alternative adhesins. The relatively small number of commensal Candida cells in the oral flora raises the possibility that strategies can be devised to prevent oral colonization and infection. However, the variety of oral niches and the complex adherence mechanisms of the yeast mean that such a goal will remain elusive until more is known about the contribution of each mechanism to colonization.

Salivary metals, age, and gender correlate with cultivable oral Candida carriage levels

“…Saliva was collected between 8 and 11 AM. Candida colonization can be described as a stable population in the oral cavity that must adhere to host surfaces to be maintained [23]. Therefore, we determined CFU per millilitre whole saliva as an aggregate indication of oral colonization.…”

“…There is a substantial overlap in the range of carriage in asymptomatic carriers (2–888 CFU/mL saliva) and those with disease (22–5,000 CFU/mL saliva) [22]. Moreover, average salivary carriage in healthy individuals is considered to be between 300 and 500 CFU/mL [23]. High C. albicans carriage is associated with higher levels of calprotectin in saliva [10], suggesting that nutritional immunity has an important role in maintaining commensal levels of C. albicans.…”

Adhesion of Candida albicans and Candida dubliniensis to acrylic and hydroxyapatite

“…Moreover, growth conditions in the oral cavity are so poor that cells have to adhere to be maintained [2]. So, an essential pre-requisite for the successful colonisation of host tissues by these micro-organisms is the ability to adhere to superficial epithelial cells, or to a closely associated surface [7].…”

Candidoses associées aux cathéters

“…L'efficacité in vivo de verrous antifongiques par l'amphotéricine B liposomale utilisée à 10 g/l et laissée en place 8 h/j pendant 7 jours a été évaluée par la numé-ration des levures après mise en culture du cathéter. L'étape préalable à la colonisation est représentée par l'adhérence des blastospores à la surface des biomatériaux recouverts d'un film glycoprotéique provenant de l'hôte [11,12]. Cet attachement initial est très rapidement suivi du développement fongique [13].…”