Involvement of ADH1, IPT1 and PMT Genes in Candida albicans Pathogenesis - Biotechnology of Fungal Genes - page 73

Figure 1. C. albicans before and after contact with human oral epithelial cells. C. albicans
was grown in Sabouraud dextrose agar culture medium for 24 h, observed under an
optical microscope and photographed (a). The yeast was cultured in the presence of
oral epithelial cells for 3 h at 37°C. One aliquot was taken for C. albicans observation
under an optical microscope (b). The photo reveals the yeast's morphological changes
after only 3 h post-contact with the epithelial cells. Bar = 10 µm.
(Color image of this fi gure appears in the color plate section at the end of the topic.)
In the last few decades, the number of reports on superfi cial Candida
infections associated with the administration of broad-spectrum antibiotics
(López-Martínez 2010) has increased and with the rise of HIV infections
(Johnson 2010) oral candidiasis has gained greater attention. Up to 90% of
HIV-infected individuals suffer from oropharyngeal candidiasis (Egusa et
al. 2008). Because Candida species are part of the oral cavity's normal fl ora,
oral candidiasis should thus be seen as a specifi c endogenous infection.
Although oral candidiasis has been considered to be primarily an
opportunistic infection, it may nevertheless develop in otherwise healthy
individuals. Clinical manifestations of candidal colonization depend on
a series of factors that include the adherence mechanisms, the strain of
C. albicans involved, its overgrowth, the host's immune incompetence
(local and systemic) and the oral environment (Sharon and Fazel 2010).
Acute and chronic forms of oral candidiasis may have a variety of clinical
manifestations. The three major clinical variants are the pseudomembranous
and erythematous types in the acute or chronic form and the chronic
hyperplastic type that can be either nodular or plaque-like ( Fig. 2). Of
particular interest is denture stomatitis, which represents the most prevalent
kind of oral Candida -associated lesions (Sharon and Fazel 2010).
Pseudomembranous candidiasis (Thrush)
The pseudomembranous form, also called “thrush”, is the prototype of oral
infections by C. albicans . It may occur at any age but is predominantly seen
in infant, elderly, immunocompromised and debilitated patients. Candida
establishes in the oral cavity of the newborn by spreading directly from the