Clinical and pathogenicity aspects of Candida species

Candida species normally exist as commensals of the skin and mucosa, but they are also opportunistic pathogens, with the ability to cause a variety of superficial and invasive diseases. Among the several of Candida species, Candida albicans remains the most common fungal isolate, mainly from blood cultures in the diagnostic of nosocomial bloodstream infection. However, the rates of candida infections caused by other species have increasing significantly in the last years. The pathogenesis of the candidiasis is influenced by the predisposing factors of the host and virulence factors expressed by the yeast involved in the infection. In this way, various characteristics of Candida species have been proposed as virulence factors that enable fungal adhesion, colonization and subsequent penetration of tissues in susceptible hosts. In this regard, secretion of hydrolytic enzymes such as lipases, aspartyl proteinases and hemolytic factor contributes to candida pathogenesis by degrading cell membranes and extracellular proteins. In addition, the ability to recognize and adhere to host cells and/or tissues and biofilm formation has been implicated as potential virulence factors for at least one Candida species