oral mycology

Dr.Baha,Hamdi.AL-Amiedie

Ph.D.Microbiology

Characteristic of fung

i1-• Eukaryotes

2- No chlorophyl (distinguishes them from

plants and algae)

3- Unicellular to filamentous

4- Rigid cell wall

5-Spore bearing stages in the life cycle

6-Usually reproduce by sexual and asexual

means

7-Insensitive to antibacterial antibiotics

Morphological types of fungi

Three major groups

1. Moulds

2. Yeasts

3. Mushrooms

Dimorphic fungi – fungi that have both a

yeast stage and a mould stage

In many cases vegetative cell of hypha contains more

than one nucleus – typical hypha is a nucleated tube

containing a cytoplasm ( a coenocytic) and no septa

(cross walls)

• Septate hyphae have one or two nuclei per cell

Fungal infection types

1-Rang from superfical infection to ovewhelming systemic infections that are rapidly fatal in the compromised host

2-they are increased in frequency as result of increased used of antibiotics

Corticostroids& cytotoxic drugs

3-classified into superfical, cutaneous

Subcutaneous&systemic infection;Systemic infection are subdivied into those caused by opportunistic fungi & by those caused by pathogenic fungi

such as histoplasmosis, are found almost exclusively in the USA, while others such as mucormycosis are found particularly in immuno-compromised individuals.

Oral candidosis

Candida infections confined to the mouth are relatively common and “ Causes of generalized candidosis with oral manifestations, however, are uncommon. The laboratory diagnosis of oral candidosis is

The most common oral fungal infection is candidosis, caused by Candida spp., particularly C. albicans.

About 50% of the population are symptomless oral carriers of Candida spp., but only a small proportion of individuals have the signs and symptoms of infection.

The pathogenesis of oral candidosis involves a complex interaction between host defence mechanisms and fungal virulence factors.

The common forms of oral candidosis 1.pseudomembranous,

2. erythematous (including HIV-associated infection and denture-related candidosis),

3. hyperplastic

4.angular  cheilitis

Chronic mucocutaneous candidosis .

Treatment :

consists of correcting predisposing factors and prescribing oral or systemic antifungal agents

The development of resistance in Candida spp. to azole drugs such as fluconazole may follow prolonged treatment and has been linked to treatment failure.

Oral lesions caused by fungi other than Candida spp. are rare and are usually secondary to primary infections of the lungs.

Laboratory diagnosis

1-microscopic examination:Direct  examination with potassium hydroxide(KOH) a weat amount of skin scrapings break down the human cell enhancing the visibility of infected fungus.

2-laboratory culture: using special medium (sabourauds dextrose medium) enriched media.