LabM 421 Morphology Quiz

Malassezia furfur

-Causes tinea versicolor

-Requires lipid source (sterile olive oil)

-Yeast with “spaghetti and meatballs” morphology

Dematophytes

-Septate, hyaline, filamentous hyphae

-Infection of superficial, keratinized structures (skin, hair, nails)

-Dx often via KOH prep or Calcoflour + colony morphology

Trichophyton rubrum

-Skin and nail infections (most common worldwide)

-Colony surface is white/buff

-Colony bottom is red

-Tear shaped microconidia (“birds on a wire”)

-Negative for hair shaft penetration

-Dermatophyte

Trichophyton mentagrophytes

-Looks similar to T. rubrum

-Positive for hair perforation

-Dermatophyte

Microsporum canis

-Skin and scalp infections usually from pets

-Colony surface is white with yellow edges

-Spindly, rought macroconidia with >6 cells/compartments

Microsporum gypseum

-Scalp and skin infections, common in animals

-Oval, rough walled macroconidia with <6 cells/compartments

Epidermophyton floccosum

-Skin and nail infections

-Colony is yellow, olive-gray, or khaki

-Reverse of colony is orange-brown

-Smooth club shaped macroconidia with rounded ends, often found in clusters of 2-6 cells

-No microconidia

Histoplasma capsulatum

-Small, narrow yeast in tissues (easy to confuse with other pathogens)

-Septate, hyaline, hyphae with spiny macroconidia

Blastomyces dermatitidis

-Broad based budding yeast (BBB) often with double contours

-Mold form is not very distinct

Coccidioides immitis

-Spherule form at 47%

-Mold form

• Hyaline,* septate with “Train tract”), arthroconidia

Paracoccidioides brasiliensis

-Yeast-like, round “mariner’s wheel” with circumferential meeting

-Mold: septate, yaline,terminal and intercalary chlamydospores

-Mold: sepate, hyaline, terminal and intercalary chlamydospores

-Don’t mix up with H. capsulatum’s mold

Sporothrix schenii

-Causes: “rose gardener’s disease”

-Yeast: Cigar shaped, narrow based

-Mold: hyaline, septate with “rosettes) of microconidia

Aspergillus fumigatus

-Blue-green colonies

-Single row of phialides covering top 2/3 of vesicle

Aspergillus flavus

-Yellow-green or olive colonies

-Circumferential phialides

Aspergillus niger

-Dark-brown/black colonies

-Vesicle has two rows of phialides covering the whole surface

-Black conidia

Fusarium spp.

-Violet colonies

-”Canoe” or “banana” microconidia

Acremonium spp.

-Grey, white, or pink colonies

-Long, narrow, unbranched phialides with clusters of microconidia

Penicillium spp.

-Usually a contaminant, but can cause infection

-Blue-green powdery colonies with white border

-”Skeleton hand” phialide and conidia arrangements

Scopulariopsis spp.

-Contaminants but can cause infection

-Powdery brown/tan colonies

-Rough “lemon drop” conidia

Zygomycetes

-”Lid lifters”

-Broad, non-septate hyphae

-Mostly cottony and white colonies that grew quickly

Rhizopus spp.

-Rhizoids and unbranched sporangiophores

-Sporangiophores = sac of spores

Mucor spp.

-No rhizoids

-Sporangia fall apart easily

Alternaria

-Dematiaceous mold

-Brownish black colonies

-Chains of club-shaped conidia with transverse and longitudinal separations

Microsporidia

-Fungi

-Spores <4 um

Cryptosporidium parvum

-Oocysts 4-6 um (slightly smaller than RBC)

Cyclospora cayatanensis

-Oocysts 8-10 um (slightly larger than RBC)

Cystoisospora belli

-Oocysts 4-6 um (slightly smaller than RBC)

Trypanosoma brucei

-Larger organism

-S or C shaped

-Smaller posterior kinetoplast

Trypanosoma cruzi

-Smaller

-C shaped

-Large posterior kinetoplase

Plasmodium vivax

-Retics infected (large RBCs)

-Ring forms >1/3 size of RBC

-Mature troph is ameboid, fills RBC

-Schizont has 12-24 merozoites

-Gametocytes are large and oval

-Schuffner’s dots

Plasmodium ovale

-Retics inected (large RBCs)

-Ring forms >1/3 size of RBC

-Mature trophs more compact than P. vivax

• Comet forms

-Schizont has 6-14 merozoites

-Gametocytes are large and oval

-Schuffner’s dots

Plasmodium malariae

-Infects senescent RBCs (small to normal)

-Ring form 1/3 size of RBC, thick

• Bird’s eye

-Mature trophs = band and basket forms

• Do not fill RBC

• Prominent pigment

-Schizont has 6-12 merozoites

• Rosette forms

-Gametocyte can fill RBC

Plasmodium falciparum

-Only ring forms and gametocytes seen in blood

-Small, delicate ring forms

• Applique forms

• Multiple infections

• Multiple chromatin dots

-Gametocyte = banana shaped

Entamoeba histoloytica Cyst

-Up to 4 nuclei

-Chromatoida body with smooth ends

Entamoeba histolytica Trophozoite

-15--20 microns

-Small, central karyosome and fine peripheral chromatin

-May see erythrophagocytosis (diagnostic)

Entamoeba coli Cyst

-Up to 8 nuclei

Entamoeba coli Trophozoite

-20-25 microns

-Eccentric karyosome

-Clumpy peripheral chromatin

Entamoeba hartmanni Cyst

-Looks like a miniature E. histolytica

-Up to 4 nuclei

Entamoeba hartmanni Trophozoite

-5-10 microns

-Looks like a miniature E. histolytica

-No ingested RBCs

Endolimax nana Cyst

-No peripheral chromatin

-4 nuclei with karysomes

Endolimax nana Trophozoite

-6-10 microns

-Hard to distinguish from Iodamoeba buetschlii

Iodamoeba buetschlii Cyst

-No peripheral chromatin

-Prominent vacuole

Iodamoeba buetschlii Trophozoite

-8-20 microns

-Vacuolated and granular

Giardia intestinalis Cyst

-4 nuclei

Giardia intestinalis Trophozoite

-Pear shaped

-Central axoneme

-2 nuclei

-2 sucking disks

-2 parabasal

Chilomastic mesnili Cyst

-”Shepard’s crook” cytostome

Chilomastix mesnili Trophozoite

-Pear shaped

-Anterior end is rounded, nucleus

-Posterior end is tapered

-”Shepherd’s crook” cytostome

Dientamoeba fragilis

-No cyst

-Trophozoite

• Round

• Binucleate

• Internal flagellum

Balantidium coli

-Cyst

• Infrequently seen

-Trophozoite

• Large, up to 200 microns

• Cytostome and cilia

Enterobius vermicularis

-Egg

• Thin walled oval with flat side

• Found in scotch tape prep rather than stool

Trichuris trichiura

-Egg

• Thick walls

• Bilateral polar plugs

Ascaris lumbrocoides

-Egg

• Rough, bumpy surface

• Thick shell, stained with bile

Hookworm

-Egg

• Necatur and Ancylostoma eggs are indistinguishable

• “Steak on a plate”

Strongyloides stercoralis

-Worm (rhabditiform larvae)

• Short buccal canal

• Bulbar portion of esophagus

• Genital primordium

Taenia saginata/solium Egg

-Indistinguishable between the two

Taenia saginata Worm

-Smooth scolex with four suckers

-Proglittids

• Longer than they are wide

• >13 uterine branches

Taenia solium Worm

-Scolex with four suckers with armed rostellum

-Proglottids

• Longer than they are wide

• <13 uterine branches

Diphylobothrium latum Egg

-Are smooth with shoulderless operculum and small knob

• Around 60 microns

Diphylobothrium latum Worm

-Scolex is almond-shaoed wuth 2 sucking grooves

-Proglottids wider than long

Hymenolepid diminuta

-Eggs have thin inner and outer shells

• About 80 microns

• Polar filaments between shells

• Embryo with hooklets inside inner shell

Hymenolepis nana

-Eggs

• About 40 microns

• Two shells with polar filaments between

• Oncosphere has six hooklets

Fasciola/Fasciolopsis

-Eggs are identical between the 2 general

• Looks similar to D. latum but much larger

-120 microns

-No shoulders

-Abopercular knob present

Clonorchis sinensis

-Eggs are about 30 microns

-Shouldered operculum

-Abopercular knob

Paragonimus westermani

-Eggs are around 100 microns long

• May be in stool or sputum

• Shouldered operculum

• Thick abopercular end, but no knobs

Schistosoma mansoni

-Eggs are around 150 microns long

• Lateral spine

Schistosoma haematobium

-Eggs are around 150 microns long

• Can be found in stool or urine

• Terminal spine

Schistosoma japonicum

-Eggs are around 80 microns long

• Inconspicuous “spine”