Infectious Disease Cytology Flashcards
What is the organism in this tracheal wash from a horse?
Streptococcus (streptococcal pneumonia)
If your gram stain looks like this, what does it tell you?
There was inadequate decolorization. If decolorized properly, the nuclei of the neutrophils would be pink, not still purple
There is also stain precipitate
What kind of organism is this?
Clostridium spp
They are anaeorbic gram + rods approx 1x4 um and when they have a subterminal endospore, they have a club shape
Dx by anaerobic culture or serology
What kind of bacteria is this?
Filamentous bacteria
What kind of bacteria is this?
Filamentous bacteria
What kind of bacteria is this?
A filamentous ‘beaded’ rod
What are two common filamentous bacteria?
Actinomyces
Nocardia
What stain should you do to confirm a Mycobacterial infection? Why?
Acid fast stain
The organisms don’t stain well w/ normal Romanowsky stains b/c of the high lipid content of their cell wall
What kind of bacteria is present?
(second picture is w/ acid fast stain)
Mycobacterium spp
Intracellular and acid fast positive
What kind of bacteria is this (small, no cell wall, variable shape)?
Mycoplasma
What kind of bacteria is present in this conjunctival scraping from a cat?
Mycoplasma
There is also a chlamydia initial body (purple dot at 9 o’clock)
What does this TTW contain?
Fungal hyphae
What does this slide show?
Fungal hyphae with neutrophilic inflammation
What stain is this that is being used to highlight the fungal hyphae?
GMS stain
What does this FNA from a cutaneous mass on a dog show?
Dermatophyte infection – spores/conidia may resemble yeast
What is this organism found in a LN aspirate from a dog?
Cryptococcus neoformans – and infectious yeast
Characteristic ‘halo’ is due to thick, non-staining polysaccharide capsule w/ thin cell wall
What organisms is this found in a nasal flush from a cat?
Cryptococcus neoformans
Notice the non-staining capsule and narrow based budding
When do you use india ink ‘staining’?
Not really a stain: fills background area to highlight yeast//capsule
Useful only to help ID yeast found in fluid samples that have no background cells, mucus, or protein to highlight the capsule (CSF, urine, wash fluid)
what organism is this from a nasal flush from a cat?
(india ink prep)
Cryptococcus neoformans
What organism is this? What are its characteristics?
Blastomyces dermatitidis (Blastomycosis)
- large extracellular yeast
- ‘big blue balls with broad based budding’
- accompanied by granulomatous or pyogranulomatous inflammation
- Begins as resp dz and can become systemic
What does this canine LN aspirate show?
Pyogranulomatous inflammation and blastomycosis
What organism is this? What inflammation is show?
Blastomyces dermatitidis
Pyogranulomatous inflammation
What organism is this? What are its characteristics?
Coccidioides immitis (Coccidioidomycosis)
- v. large
- thick cell wall
- no capsule
- no external budding
- endospore forming spherules in tissue
- infection thru wound or inhalation of aerosolized arthrospores and can cause lung, bone, CNS, ocular, skin infections w/ granulomatous inflammation
What organism is this? What are its characteristics?
Histoplasma capsulatum
- small, round yeast (1-4 um)
- basophilic nucleus and thin cell walls
- may be phagocytized by neuts or macs
SE US
MI/MO/OH River valleys
What organism is this?
Histoplasma capsulatum
What organism is this within a macrophage (sample from BAL)?
Histoplasma capsulatum
What organism is this? What are its characteristics?
Sporothrix schenckii (Sporotrichosis)
- variably shaped yeast (round to oval, elongated ‘cigar’ shaped, etc)
- approx 3-5um in diameter
- thin, clear cell wall and pale blue cytoplasm
- Cause cutaneous, systemic, and cutaneolymphatic infections; granulomatous or pyogranulomatous inflammation
Which organism is this, obtained from a draining cutaneous lesion in a cat?
Sporothrix
What organism is seen here? What are its characteristics?
Malassezia pachydermatis
- opportunistic fungal organism of skin and ear canal
- small yeast (2-6um) w/ broad based budding
- shoeprint/peanut
- causes otitis externa and seborrheic dermatitis
What is this organsim? What are its characteristics?
(sample from urine sediment)
Candida albicans
- thin-walled, dense staining budding yeast
- approx 2-6um
- medium based budding; may form pseudohyphae (strings of elongated yeast that do not separate after budding)
- opportunistic fungal organism of skin, GI, mm
There are also bacteria on this slide
What are these organisms, found in a TTW of a cat?
(normally subclinical infection but immunosuppression can cause dz)
Toxoplasma gondii
- protozoa
- organisms (tachyzoites, bradyzoites) are rarely found in cytology samples
- crescent shaped, 1-4um, metachromatic nucleus, pale basophilic cytoplasm, may be extracellular, w/in macs, or w/in epithelial cells
Who are these little dudes? What are characteristics of their infections?
Leishmania infantum, chagasi, braziliensis, donovani
- protozoa transmitted by sandflies
- found in tropics, subtropics, southern europe, mediterranean
- cause cutaneous, visceral/systemic dz
- infected dogs usu have hyperglobulinemia (immune complex dz may occur)
Who are these little parachuting assholes?
(sample is from LN aspirate)
Leishmania amastigotes w/in macrophages
What kind of organism is this? What kind of dz does it cause?
(acid fast stain)
Cryptosporidium parvum
- a coccidial parasite found in GIT
- causes diarrhea, esp young ruminants
- zoonotic
What type of algal organisms are these?
Prototheca zopfii, P. wickerhamii
- round to oval algae w/o chlorophyll
- endospores (~5-20um) are basophilic and granular w/ clear halo and single nucleus
- found in sewage contaminated water and food and infections frequently assoc’d w/ immunosuppression
Cats can develop cutaneous dz (large firm nodules onlegs head, paws, tail)
Dogs can develop both cutaneous or systemic dz (GIT, eye, NS)
What terrible organism causes these terrible things? What are its characteristics?
((GMS stain))
Pythium insidiosum (pythiosis)
- resembles fungal organism but is actually a water mold
- infection via standing in or drinking contaminated water
- cutaneous lesions = exudative, ulcerated masses on extremities (swamp cancer)
- GI pythiosis = wt loss, v/d, intestinal masses
- broad, flat, poorly septate, branching hyphae are found in lesions w/ pyogranulomatous inflammation +/- eos
- stain poorly w/ routine stain but are GMS + and PAS negative
