Medical Microbiology

Morphologyandculture.GramstainingofprimarypreparationsrevealsC.

albicanstobeaGram-positive,budding,ovalyeastwithadiameterofap-

proximately 5 lm.Gram-positivepseudohyphaeareobservedfrequently

andseptatemyceliaoccasionally(Fig.6. 2 ).

C.albicanscanbegrownontheusualculturemediums.After 48 hoursof

incubationonagarmediums,round,whitish,somewhatrough-surfacedcol-

oniesform.Theyaredifferentiatedfromotheryeastsbasedonmorphological

andbiochemicalcharacteristics.

Pathogenesisandclinicalpictures.Candidaisanormalinhabitantofhuman

andanimalmucosa(commensal).Candidainfectionsmustthereforebecon-

sideredendogenous.Candodosesusuallydevelopinpersonswhoseimmu-

nityiscompromised,mostfrequentlyinthepresenceofdisturbedcellular

immunity.Themucosaareaffectedmostoften,lessfrequentlytheouter

skinandinnerorgans(deepcandidiasis).Inoralcavityinfections,awhite,

stubbornlyadherentcoatingisseenonthecheekmucosaandtongue.Patho-

OpportunisticMycoses(OM) 363

ClinicalFormsofCandidosis

a

b

Fig.6. 3 aOralsoor;surfaceinfection

ofcheekmucosaandtonguebyCandida

albicansinanAIDSpatient.

bChronicmucocutaneouscandidiasis

inachildwithacellularimmunodefi-

ciencysyndrome.

6

Kayser, Medical Microbiology © 2005 Thieme