Aspergillosis

1
Aspergillosis

• Laboratory Identification
• Aspergillus in tissue display thin or thick
  dichotomous branching septate hyphae
• They stain optimally with methenamine silver
  stain
• Microscopic generic identifying characteristics
  include vesicles with phialides, and
  phialoconidia

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Aspergillosis
Dichotomous Branching
Septate hyphae
Histopathology Stained Tissue
3
More dichotomously branched septate hyphae
Phialoconidial head
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Aspergillosis

• Laboratory Identification - colonial
• Colonies have granular surfaces on flat or heaped
  and folded colonies
• Colony colors are due to colored conidia which
  range from yellow, green, blue-green, cinnamon,
  or black
• Aspergillus species grow very rapidly
• They grow to mature colonies in only a few days
  under optimum growth conditions

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Various Aspergillus species Mature Colonies
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Aspergillosis

• Laboratory Identification
• Species identification depends on color, number
  of rows of phialides, and whether the phialides
  grow all over the vesicle or only on upper
  portion
• Species identification usually done by a mycology
  specialists in reference labs
• Sometimes species identification is accomplished
  serologically

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Aspergillus fumigatus
Phialoconidia in chains
Phialides in Single Row
Vesicle
Conidiophore
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Aspergillus Species
Aspergillus nidulus
Aspergillus niger
Aspergillus clavatus
Aspergillus terrus
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Zygomycosis

• Etiology
• Zygomycetes are primitive, fast growing,
  terrestrial, fungi with a cosmopolitan
  distribution - to date 665 species have been
  described although infections in humans and
  animals are generally rare
• Any zygomycete can cause zygomycosis but the most
  common genera isolated from human clinical
  specimens are Rhizopus, Mucor, and Absidia
• Not on test less common genera are Rhizomucor,
  Syncephalastrm, Cunninghamella, Circinella and
  others

10
Zygomycosis

• Epidemiology
• Zygomycetes are widely distributed in nature
  inhabitanting soil, dung, and vegetable matter.
  They are among the most common bread moulds
• Zygomycosis in the debilitated patient is the
  most acute and fulminate fungal infection known.
• Humans usually become infected through inhalation
  of airborne spores (sinus and pulmonary disease)
  or contaminated food (gastrointestinal disease)