22: Fungi of relevance to dentistry

Chapter 22 Fungi of relevance to dentistry

The study of fungi is called mycology. Fungi are eukaryotic microorganisms, as opposed to bacteria together with Archaea that are prokaryotic (Chapter 2). By far the most important fungus of relevance in dentistry is a yeast belonging to the genus Candida. It is an oral commensal in about half of the general population. In this chapter, the general characteristics of some medically important fungi will be given, but the emphasis will be on fungal infections of the oral cavity – the oral mycoses, especially those caused by the Candida species.

Human mycoses

Human infections caused by fungi can be divided into:

Yeasts

Yeasts are unicellular, oval or spherical organisms, 2–5 µm in diameter, and stain positively by the Gram method (Fig. 22.2). They are commonly seen to have lateral projections or buds called daughter cells. These gradually enlarge in size until they split off from the parent or mother cell to produce the next generation. Most yeasts develop pseudohyphae (chains of elongated budding cells devoid of septa or cross walls) but only a few form true hyphae (septate hyphae). Yeasts of the genus Candida, the most important fungal pathogen in the oral cavity, also form pseudohyphae. It is a common yeast that lives in the oral cavity of about half of the population and is also a resident commensal of the gut. It can cause either superficial or systemic candidiasis (synonym: candidosis). The superficial disease affects:

The infection is usually endogenous in origin. Several species in the genus Candida are found in humans, including C. albicans, C. glabrata, C. krusei and C. tropicalis (Fig. 22.3), but C. albicans is responsible for the vast majority of infections (>90%). Candida dubliniensis is a newly recognized species of Candida very similar to C. albicans. First isolated from the oral cavity/>

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Jan 4, 2015 | Posted by in General Dentistry | Comments Off on 22: Fungi of relevance to dentistry
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