Thermally Monomorphic Molds

saprophytes

monomorphic - mold only

rapid grower 3-5days

colonies often brightly colored

inhibited by cycloheximide

have low inherent virulence → infn needs pt to be i-compromised

zygomycosis? caused by who?

disease often disseminates in i-compromised pt, diabetes, lupus erthematous

common Zygomycetes: Rhizopus, Mucor, Lichtheimia sp

ribbon-like, non-septate hyphae, lid-lifter (aerial hyphae), cottony

Zygomycetes structures

stolon - part of hyphae

apophysis - sides of sporangium?

Rhizopus sp

coarse rhizoids at base of sporangiophores

not branched sporangiophores

Mucor sp.

sporangiophores tend to branch

not rhizoids

sporangium is large, spherical

Lichtheimia (formerly Absidia sp)

sporangiophores branch freely

rhizoids are not as coarse and internodal

columella are semicircular, knob at top

apophysis = like martini glass

Hyaline molds

colorless septate hyphae, conidia in chains

Aspergillus sp

Penicillium sp

Paecilomyces sp

Scopularopsis

Aspergillus m/c sp iso’d from hospital pt

A. fumigatus (m/c)

A. flavus

A. niger

A. terreus

rapid growing hyaline mold, septate hyphae, foot cell, swollen vesicle, dichotomous branching at 45 degrees (similar in Fusarium sp.)

Aspergillus fumigatus

can grow on SBA

blue-green, white edges

upper 2/3 of vesicle is covered w UNISERIATE phialides

Aspergillus flavus

olive-lime-yellow

globose vesicle w/ phialides around entire circumference

both UNI- & BISERIATE

Aspergillus niger

conidia jet black & granular

vesicles are obscured by dense conidia

BISERIATE, cover entire vesicle

Aspergillus terreus

conidia = cinnamon, buff, brown, orange brown

BISERIATE

conidia form long chains

fan-like

Aspergillus tanneri

harder to isolate → no conidiophores on PDA → molecular testing

can cause chronic invasive pulmonary & disseminated disease

hard to treat w Afx

Cleistothecia

some Aspergillus produce Cleistothecia-sexual state

rapid test for Aspergillus

Galactomannan

most useful in pt w hematopoietic cell transplants

false + on pt w IV-Abx, or gluconate, or citric acid …

fungitell (1,3)-Beta-D-Glucan test

rapid dx test for any fungi, highly sensitive

not good for

Cryptococcus (low levels)

Zygomycetes

yeast phase of Blastomyces dermatidis

Penicillium sp

usually grow fast

powdery white green

brush-like fruiting head

Fusarium sp

cotton-like

lavendar, rose, red, or red-purple

microconidia = fusiform or oval shape from delicate lateral phialides

macroconidia = curved w 3-4 septae

chlamydospore = large, circular

Fusarium infns in i-compromised pts

sinusitis,

keratitis (contact lens soln),

onychomycosis (nail),

tinea pedia (athletes foot),

interrigo

more severe infn in burns, decubitis ulcers, septic arthritis assoc w steroid injections

invasive infns in AML, hematopoietic stem cell, or prolonged neutropenia pts

hyaline mold that produces a yeast-like form (blastospore) + hyphae in tissue

Fusarium sp

___ assoc’d w alimentary toxic aluekia

Fusarium sp

Fusarium resistance

Fusarium solani = most R

intrinsically echinocandin-R

azole-R

angioinvasive fungi

Zygomycetes group

Fusarium sp.

Paecilomyces sp

sinusitis, eye infns, EC, nephritis, cutaneous,… in i-compromised pts

cottony pink, white, yellow

looks like Penicillium, but phialides are not parallel and taper, more delicate

Scopulariopsis sp.

infn: nails, tissue, lung, pts w BM transplant, chemotherapy

khaki color

conidia are spiky/rough

phialide are thicker

Alternaria sp

subcutaneous tissue, nails, eye, nasal sinus

DEMATIACEOUS MOLD (melanin in cell wall), not hyaline

dark gray, brown on front

black on back

conidia = large, muriform, bricklike arrangement, should be chains of 3!