Medical Microbiology

Therapy.High-doseamphotericinB,administeredintime,istheagentof

choice.Azolescanalsobeused.Theechinocandincaspofunginhasbeenap-

provedinthetreatmentofrefractoryaspergillosisassalvagetherapy.Surgical

removaloflocalinfectionfoci(e.g.,aspergilloma)isappropriate.

Cryptococcusneoformans(Cryptococcosis)

Morphologyandculture.C.neoformansisanencapsulatedyeast.Theindi-

vidualcellhasadiameterof 3 – 5 lmandissurroundedbyapolysaccharide

capsuleseveralmicrometerswide(Fig.6.5a).

C.neoformanscanbeculturedonSabouraudagarat 30 – 358 Cwithanin-

cubationperiodofthreetofourdays(SeeFig.6.5b).

Pathogenesisandclinicalpicture.Thenormalhabitatofthispathogenissoil

richinorganicsubstances.Thefungusisveryfrequentlyfoundinbirddrop-

pings.Theportalofentryinhumansistherespiratorytract.Theorganisms

366 6 FungiasHumanPathogens

Cryptococcusneoformans

a^50 μm

b

Fig.6. 5 aInkpreparation

from cerebrospinal fluid;

negative image of thick,

mucoid capsulesurround-

ingtheyeastcells.Clinical

diagnosis:cryptococcalme-

ningitis.

b Culture on Sabouraud

agar:whitish,creamycolo-

nies.

6

Kayser, Medical Microbiology © 2005 Thieme