Oral MycologyOral Mycology

lectuerlectuer (19)(19)

Dr.Baha,Hamdi.ALDr.Baha,Hamdi.AL--AmiedieAmiedie

Ph.D.MicrobiologyPh.D.Microbiology

Characteristic of fungiCharacteristic of fungi

11--•• EukaryotesEukaryotes

22-- NoNo chlorophylchlorophyl (distinguishes them from(distinguishes them from

plants and algae)plants and algae)

33-- Unicellular to filamentousUnicellular to filamentous

44-- Rigid cell wallRigid cell wall

55--Spore bearing stages in the life cycleSpore bearing stages in the life cycle

66--Usually reproduce by sexual and asexualUsually reproduce by sexual and asexual

meansmeans

77--Insensitive to antibacterial antibioticsInsensitive to antibacterial antibiotics

ComparisingComparising between fungi &Bacteriabetween fungi &Bacteria

Cell wall structure of fungiCell wall structure of fungi

Morphological types of fungiMorphological types of fungi

Three major groupsThree major groups

1. Moulds1. Moulds

2. Yeasts2. Yeasts

3. Mushrooms3. Mushrooms

Dimorphic fungiDimorphic fungi –– fungifungi that havethat haveboth aboth a

yeast stage and a mould stageyeast stage and a mould stage

In many cases vegetative cell ofIn many cases vegetative cell of hyphahyphacontains morecontains more

than one nucleusthan one nucleus –– typicaltypical hyphahypha is ais anucleated tubenucleated tube

containing a cytoplasm ( acontaining a cytoplasm ( a coenocyticcoenocytic))and no septaand no septa

(cross walls)(cross walls)

•• SeptateSeptate hyphaehyphae have one or two nucleihave one or two nucleiper cellper cell

Asexual sporesAsexual spores

Asexual reproductionAsexual reproductionAsexual spore formation:Asexual spore formation:

•• chlamydosporeschlamydospores (formed within(formed withinsporangia)sporangia)

•• conidia (formed naked at tips ofconidia (formed naked at tips ofhyphaehyphae))

•• budding (cell division)budding (cell division)•• fragmentation (of mycelium)fragmentation (of mycelium)

Asexual sporesAsexual spores

Sexual sporesSexual spores

Sexual spores areSexual spores areresistant to dryingresistant to drying

heating, freezing, andheating, freezing, andsome chemical agentssome chemical agents

•• Not as resistant to heatNot as resistant to heatas are bacterialas are bacterial

endosporesendospores•• Either a sexual spore orEither a sexual spore or

an asexual spore canan asexual spore cangerminate and developgerminate and develop

into a newinto a new hyphahypha and Myceliumand Mycelium

Sexual sporeSexual spore

Fungal infection typesFungal infection types

11--Rang fromRang from superficalsuperfical infection toinfection toovewhelmingovewhelming systemic infections thatsystemic infections thatare rapidly fatal in the compromisedare rapidly fatal in the compromisedhosthost

22--they are increased in frequency asthey are increased in frequency asresult of increased used of antibioticsresult of increased used of antibiotics

CorticostroidsCorticostroids&& cytotoxiccytotoxic drugsdrugs33--classified intoclassified into superficalsuperfical,, cutaneouscutaneous

Subcutaneous&systemicSubcutaneous&systemicinfection;Systemicinfection;Systemic infection areinfection aresubdiviedsubdivied into those caused byinto those caused byopportunistic fungi & by thoseopportunistic fungi & by thosecaused by pathogenic fungicaused by pathogenic fungi

Oral Aspect of fungal infectionsOral Aspect of fungal infections

Fungal infections in the oral andFungal infections in the oral andperioralperioral regions occur either asregions occur either asprimary localized lesions or asprimary localized lesions or asmanifestations of systemic mycosesmanifestations of systemic mycoses..By far the most common group ofBy far the most common group offungal infections that dentalfungal infections that dentalpractitioners diagnose and treat arepractitioners diagnose and treat arecaused by Candidacaused by Candida sppspp.. Some of theSome of therarer mycoses with oralrarer mycoses with oralmanifestationsmanifestations