MycologyOpportunistic Molds

Division of Medical Technology

Carol Larson MSEd, MT(ASCP)

Please click audio iconto hear Carol’s narration

Basic Characteristics

• Rapid growers (4-5 days)

• Found in soil (saprobic)

• Conidia are airborne

• Opportunistic pathogens

• Treatment

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Opportunistic Mold Classification

• Aseptate (sparsely septate) / hyaline

• Septate / dematiaceous

• Septate / hyaline

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Zygomycetes

• Lid lifters

• Sporangiospores

• Rhizoids

Aseptate (sparsely septate) hyaline hyphaeClick icon for audio

Clinical Significance

• Causes Zygomycosis (Mucormycosis, Phycomycosis)

• Predisposition– Diabetics– Malnutrition– Immunosuppressed– Prolonged antibiotic therapy

• Pathogenesis– Nasal sinuses– Migrate to brain and meninges

Aseptate (sparsely septate) hyaline hyphaeClick icon for audio

Absidia species

• Internodal rhizoids

Aseptate (sparsely septate) hyaline hyphaeClick icon for audio

Mucor species

• No rhizoids

Aseptate (sparsely septate) hyaline hyphaeClick icon for audio

Rhizopus species

• Nodal rhizoids

Aseptate (sparsely septate) hyaline hyphaeClick icon for audio

In Review …

• Aseptate (sparsely septate) hyaline hyphae

• Zygomycetes– Lid lifters, sporangiospores– Absidia – internodal rhizoids– Mucor – no rhizoids– Rhizopus – nodal rhizoids

• Zygomycosis

Aseptate (sparsely septate) hyaline hyphaeClick icon for audio

Opportunistic Mold Classification

• Aseptate (sparsely septate) / hyaline

• Septate / dematiaceous

• Septate / hyaline

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Alternaria species

• Colony morphology:

• Microscopic morphology:

Septate / dematiaceous hyphaeClick icon for audio

Cladosporium species

• Colony morphology:

• Microscopic morphology:

Septate / dematiaceous hyphaeClick icon for audio

In Review …

• Septate, dematiaceous hyphae

• Alternaria species

• Cladosporium species

• Generally nonpathogenic

Septate / dematiaceous hyphaeClick icon for audio

Opportunistic Mold Classification

• Aseptate (sparsely septate) / hyaline

• Septate / dematiaceous

• Septate / hyaline

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Aspergillus species

• Causes Aspergillosis

• Predisposed– Debilitated & immunocompromised

• Pathogenesis– Inhale conidia– Pulmonary disease– Systemic

Septate / hyaline hyphaeClick icon for audio

Aspergillus fumigatus

• Colony morphology:

• Microscopic morphology:

Septate / hyaline hyphaeClick icon for audio

Aspergillus niger

• Colony morphology:

• Microscopic morphology:

Septate / hyaline hyphaeClick icon for audio

Aspergillus flavus

• Colony morphology:

• Microscopic morphology:

Septate / hyaline hyphaeClick icon for audio

Aspergillus species

• Colony morphology:– Velvety, white, green

yellow, cinnamon brown, reverse varies

• Microscopic morphology:– Single or double row of

phialides covering entire vesicle

Septate / hyaline hyphaeClick icon for audio

In Review …

• Aspergillus species– A. fumigatus– A. niger– A. flavus– Many others

• Aspergillosis

Septate / hyaline hyphaeClick icon for audio

Other Opportunistic Molds

• Penicillium species

• Paecilomyces species

• Fusarium species

• Sepedonium species

Septate / hyaline hyphaeClick icon for audio

Penicillium species

• Colony morphology:

• Microscopic morphology:

Septate / hyaline hyphaeClick icon for audio

Paecilomyces species

• Colony morphology:

• Microscopic morphology:

Septate / hyaline hyphaeClick icon for audio

Fusarium species

• Colony morphology:

• Microscopic morphology:

Septate / hyaline hyphaeClick icon for audio

Sepedonium species

• Colony morphology:

• Microscopic morphology:

Septate / hyaline hyphaeClick icon for audio

In Review …

• Septate hyaline hyphae

• Opportunistic pathogens– Aspergillus– Fusarium

• Lab contaminants– Penicillium– Paecilomyces– Sepedonium

Septate / hyaline hyphaeClick icon for audio

In Summary …

• Key characteristics

• Identification methods– Colony morphology– Microscopic morphology

• Clinically significant opportunistic molds– Zygomycetes– Aspergillus fumigatus, A. niger, A. flavus– Fusarium species

Opportunistic MoldsClick icon for audio

Who am I?

Aspergillus fumigatus

Potato Dextrose Agar LPCB Stain of Slide Culture

Who am I?

Potato Dextrose Agar LPCB Stain of Slide Culture

Rhizopus species

Who am I?

Fusarium species

Potato Dextrose Agar LPCB Stain of Slide Culture

Who am I?

Penicillium species

Potato Dextrose Agar LPCB Stain of Slide Culture