Switch of phenotype as an escape mechanism of the intruder.

Phenotypic switching in Candida albicans is a reversible, high-frequency phenomenon that is readily detectable in a fungal population as changes in cell or colony morphology. Some putative attributes of virulence in C. albicans, including expression of cell wall glycoproteins, secretion of proteolytic enzymes and hypha formation have been associated with switching phenomena. C. albicans isolates from active infection tend to show a higher prevalence of phenotypic switching than those associated with commensalism. Moreover, some characteristics of azole resistance in C. albicans are compatible with a switch of phenotype. There is thus a preliminary basis of scientific evidence for a hypothesis that phenotypic switching may indeed serve as an attribute of virulence in at least one pathogenic fungus, facilitating invasion and escape from host defences.