Medical Microbiology

Sabouraudagar.Identificationconcernssolelythemorphologicalcharacter-

isticsofthefructificationorgans.Thereisnomethodofantibody-baseddi-

agnosis.

Therapy.AmphotericinBistheantimycoticagentofchoice.Surgicalmea-

suresasrequired.Controloftheprimarydisease.

Phaeohyphomycetes,Hyalohyphomycetes,

OpportunisticYeasts,Penicilliummarneffei

Thelistofclinicallyrelevantfungipreviouslynotcategorizedasclassicop-

portunistshaslengthenedappreciablyinrecentyears.Theseorganismsare

nowbeingfoundinpathogenicrolesinpatientswithmalignancies,inAIDS

patients,inpatientsundergoingcytostaticandimmunosuppressivethera-

pies,massivecorticosteroidtherapy,orlong-termtreatmentwithbroad-

spectrumantibiotics.Thetermsphaeohyphomycetes,hyalohyphomycetes,

andopportunisticyeastshavebeencreatedwiththeaimofsimplifying

thenomenclature.

Phaeohyphomycoses.Thesearesubcutaneousandparanasalsinusinfections

causedby“dematious”moldsor“blackfungi.”Todate,numerousgeneraand

specieshavebeendescribedaspathogenicagents.Commontoallisthefor-

mationofhyphae,whichappearasabrownishblackcolorduetointegration

ofmelanininthehyphalwalls.ExamplesofthegeneraincludeCurvularia,

Bipolaris,Exserohilum,Wangiella,Dactylaria,Ramichloridium,Chaetomium,

andAlternaria.Thenaturalhabitatofthesefungiisthesoil.Theyoccurworld-

wide.Phaeohyphomycetesinvadethebodythroughinjuriesintheskinor

inhalationofspores.Startingfromprimaryfoci(seeabove),thepathogens

candisseminatehematogenouslytoaffectotherorgansincludingtheCNS.

Theclinicalpicturesofsuchinfectionsmostcloselyresemblethemucormy-

cosesandaspergillosis.Iffeasible,surgicalremovalofinfectedtissuesand

administrationofantimycoticagentsisindicated.Theprognosisispoor.

Hyalohyphomycoses.Thiscollectivetermisusedformycosescausedbyhya-

line(melanin-free)molds.ExamplesofsomeofthegeneraareFusarium,

Scopulariopsis,Paecilomyces,Trichoderma,Acremonium,andScedosporium.

Thesefungiarealsofoundallovertheworld.Pathogenesis,clinicalpictures,

therapy,andprognosisarethesameasforthephaeohyphomycoses.

Opportunisticyeastmycoses.Otheryeastsbesidesthemostfrequentgenus

byfar,Candida,arealsocapableofcausingmycosesinimmunosuppressed

patients.TheyincludeTorulopsisglabrata,Trichosporonbeigelii,andspecies

ofthegeneraRhodotorula,Malassezia,Saccharomyces,Hansenula,andothers.

These“new”mycosesarenotendogenous,butratherexogenousinfections.In

OpportunisticMycoses(OM) 369

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Kayser, Medical Microbiology © 2005 Thieme