opportunistic fungi: zygomycetes

mucormycosis predisposing factors

diabetes, leukemia/lymphoma, malnutrition, barrier break, immunosuppression

rhinocerebral mucormycosis

caused by rhizopus or mucor. primary underlying condition: diabetes. hyperglycemia → enhanced growth. impaired neutrophil chemotaxis. causes convulsions. mortality >80%. treated with IV amphotericin B.

thoracic (pulmonary) mucormycosis

caused by any of the zygomycetes. primarily pulmonary: inhalation, aspiration (from rhinocerebral)

gastric mucormycosis

caused by any of the zygomycetes. primary underlying condition: malnourished children

cutaneous mucormycosis

caused by zygomycetes (mostly rhizopus). post trauma/barrier break or disseminated from other site. painful, necrotic cutaneous lesion

absidia spp colony appearance (SAB @ RT)

opportunistic infections of lungs (most common).

rapid growth, wooly, white-grayish-brown, reverse: uncolored

absidia spp microscopic appearance

hyphae (stolon): broad, aseptate, thin-walled.

sprangiophores: branched, columellas w/ swelling (apophysis) beneath sporangium, flask shaped.

sporangia: pyriform (pear shaped).

rhizoids: few, situated on stolons b/t sporangiophores

mucor spp colony appearance (SAB @ RT)

zygomycosis in severely debilitated patients, ear infections, allergies.

rapid growth, wooly, white at first then becomes gray, reverse: pale

mucor spp microscopic appearance

hyphae (stolon): broad, aseptate or sparsely septate, thick walled.

sprangiophores: branched, columnella w/o apophyses, some chlamydoconidia.

sproangia: globose (round).

rhizoids: absent

rhizopus spp colony appearance (SAB @ RT)

rapidly progressing agent of zygomycosis in brain, lungs, & intestines. patients w/ diabetic ketoacidosis, malnutrition, severe burns, immunocompromised.

rapid growth, wooly (“lid lifter”), white at first then becomes gray w/ dark tips (salt n pepper), pale reverse

rhizopus spp microscopic appearance

hyphae (stolon): broad, aseptate or sparsely septate, thin-walled

sprangophores: brown, unbranched. solitary or in tufts off stolen, diverging from point which rhozpoids form. apophysis absent or scarcely present.

sproangia: globose (round), columella

rhizoids: present (below sporangiophores

rhizomucor spp colony appearance (SAB @ RT)

occasionally agent of zygomycosis. seen in leukemia patients.

rapid growth (can grow at high temps, 54C), wooly, olive-gray to pale brown surface, white reverse.

rhizomucor spp microscopic appearance

hyphae (stolon): very broad, aseptate or sparsely, thin-walled.

sprangophores: solitary or branched (arranged in unbel), apophysis absent.

sproangia: globose (round), well developed columella.

rhizoids: rudimentary, stolons present but rare or hard to recognize

syncephalastrum spp colony appearance (SAB @ RT)

pathogenicity rare, dermatomycoses & onychomycoses.

rapid growth, wooly, pale-gray to dark gray surface, pale reverse

syncephalastrum spp microscopic appearance

hyphae (stolon): broad, aseptate or sparely (old colonies), thin-walled.

sprangophores: branched, terminate in a vesicle.

sproangia: finger-shaped (mesosporangioa), form around vesicle.

rhizoids: present

cunninghamella colony appearance (SAB @ RT)

occasional pathogen, pulmonary or disseminated zygomycosis in severely debilitated patients.

rapid growth, cottony, white to gray surface, pale reverse

cunninghamella microscopic appearance

hyphae (stolon): broad, aseptate or sparsely

sprangophores: branched, terminate in vesicle

sproangia: one-spored sporangioles, form on vesicle surface

basidiobolus ranarum colony appearance (SAB @ RT)

localized to subcutaneous tissue: woody, hard, painless nodule. can cause infection in immunocompetent hosts, commensal in intestinal tract of frogs, lizards, & toads.

rapid growth at 30C, less rapid at 37C. glabrous becoming folded & granular. buff/yellowish gray front, white reverse

basidiobolus ranarum microscopic appearance

have 2 lateral appendages that resemble beaks

conidiobolus coronatus colony appearance (SAB @ RT)

tropical chronic inflammatory disease isolated to nasal mucosa.

rapid growth at 37C, glabrous becoming powdery, buff/yellowish gray front, white reverse. white satellite colonies form with age, spores forcibly discharged by sporangiophores fill sides of inoculated tubes & plates

conidiobolus coronatus microscopic appearance

hyphae (stolon): broad, few septa (inc w age)

sprangophores: unbranched, bear single spores

sproangia: can produce hair-like appendages called villae or protuberances called papillae