8/2/2019 Cytology Poster
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Skin scraping can be used for ectoparasites and
dermatophytes. Superficial Skin Scrapes are suitable
for scabies and short body Demodex mites. Deep Skin
Scrapes are needed for long body Demodex mites.
Start by clipping a large area of hair at the site of
interest. Apply a thin layer of paraffin oil. If required,
sample 2–5 separate areas. For a Superficial Skin Scrape,
use a scalpel blade to scrape all scale in a wedge to a
collection point. Sampling should not cause bleeding.
For a Deep Skin Scrape, lift the skin and squeeze
firmly. Sampling should result in capillary bleeding.
The paraffin and expressed material should be
collected. For both methods, the sample should be
mixed with a drop of paraffin oil on a glass slide.
A cover slip should be applied and the slide examined
under low power (x40 or x100 magnification).
SKIN SCRAPING
The photomicrograph shows degenerate
neutrophils with intra- and extracellular
cocci diagnostic for bacterial infection,
most likely associated with
Staphylococcus pseudintermedius.
Bacterial overgrowth with numerous
cocci in the absence of any inflammatory
reaction can sometimes be found.
Tip: Although antibiotic therapy improves
the condition, it is important to identify
and treat the underlying disease.
Stain the slide, using a modified Wright’s staining system such as DiffQuik ® or RAPI DIFF®,
according to the manufacturers’ instructions. Dip 5-10 times in each solution, starting with
fixative solution, followed by stain solution 1 (red eosin dye) and stain solution 2 (blue thiazine
dye or methylene blue dye). Rinse with water, then air-dry or dry gently with a hairdryer.
Warning: Wear gloves or use forceps to protect your hands from long-lasting stains.
STAINING THE SLIDE
Examine under a microscope,
starting with the lowest
magnification. Initially, choose an
area showing copious purple
material, then use the lenses with
higher magnification. Closely
examine under the oil immersion
lens (x 1,000 magnification)
to search for cells and infectious
organisms.
Tip: To avoid light scatter, whichwould cause slight blurring of the
image, apply a drop of mineral
or immersion oil over the stained
material. Cover with a cover slip
and then examine microscopically.
MICROSCOPY
Adhesive tape sampling is ideal for sampling greasy
or scaly lesions. It is commonly used to find Malasseziaand bacteria, but mites and lice may also
be seen.
Use a good quality, clear sticky tape and press
firmly against the skin. Repeatedly press the tape
onto the area to be sampled until the tape is no
longer sticky.
Fasten the sticky end of the tape to a glass slide,
then add a drop of purple DiffQuik® or RAPI DIFF®
stain and stick the tape down over it. Squeeze out
the excess stain and blot away. Alternatively, stain
using the conventional DiffQuik® or RAPI DIFF®
method. Examine under oil immersion (x 1,000
magnification), using the tape as a cover slip.
Image and text courtesy of Dermcare-Vet, Australia.
TAPE SAMPLING
Cytology is a quick and easy tool in the diagnosis and management of otitis and skin infections, allowing the presence of organisms to be determined by microscopic examination of prepared slides. This process ensures more accurate targeting of the causal organisms and, as a result,
a faster resolution rate. Cytology only takes a few minutes and provides invaluable information that is helpful for both initial assessment and in monitoring the success of therapy.Cytology
IMPORTANT: Although the colour, consistency and smell of the otic discharge can give you some idea of what to expect, mere visual and olfactory examination cannot replace cytology.Typical Results
It is easier to decide what is abnormal after having
examined cytology slides from a few normal sites.
Occasional cocci and yeasts are within normal
limits, but most fields will only contain translucent,
large, polygonal cells without a nucleus i.e.
keratinocytes or skin cells.
Some of these keratinocytes are stained purple
and may be cigar shaped.
Tip: You should send duplicates of your slides to
an experienced cytologist when starting out, and
compare the cytology report with your own
findings.
Malassezia pachydermatis yeast is a very common
causal organism, often isolated alongside
Staphylococcus pseudintermedius (x 2,000
magnification). Note the peanut/footprint/
snowman/Russian doll shape of the yeast.
Malassezia pachydermatis is commonly found in
patients with atopic dermatitis, but also in other
otitis cases. The discharge is often brown/waxy
and has a characteristic yeasty odour.
Although some yeast organisms can be found in
healthy ears, treatment is advised even when relatively
small numbers of yeast cells can be seen, if the clinical
signs (erythema and/or pruritus) suggest they play
a role in the disease.
Whenever rod shaped bacteria are seen on
cytology, bacterial culture should be
performed, because the organisms could
be Pseudomonas aeruginosa.
Infections with Pseudomonas spp. may
require intense medical therapy and carry a
cautious prognosis.
The antibiotic chosen should always be
based on sensitivity testing. It is prudent t o
reserve some types of antibiotics for
conditions which have responded poorly, or
are expected to respond poorly, to other
classes of antibiotics.
Keratinocyte (cigar shaped)
NORMAL CYTOLOGY MALASSEZIA SPP. PSEUDOMONAS SPP.
MALASEB®
SHAMPOO CANAURAL®
FUCIDERM®
GEL
Dechra Veterinary Products Ltd would like to thank Ariane Neuber (DrMedVet, CertVD, DipECVD, MRCVS) and Dermcare-Vet, Australia for their help in preparing this information sheet.
The material should then
be gently transferred
onto a microscope slide
by rolling the cotton bud
along the glass surface.
Do not rub the swab
backwards and forwards
because this will disruptthe cellular components.
Tip: If marked properly,
material from both ears can
be spread onto the opposing
sides of a single slide, saving
time and slides.
PREPARING THE SMEAR
Depending on the quality of the material, the slide should be air-dried (purulent material)
or gently heat fixed with low heat (waxy/oily discharge).
Tip: A hairdryer can be used for gentle heat fixation and will also be useful for drying the
slide after rinsing. See ‘STAINING THE SLIDE’.
FIXING THE PREPARATION
It is easy to obtain a sample from the ear by gently
removing the otic discharge with a cotton bud.
Cotton bud sampling is also suitable for collecting
samples from the skin and in areas such as between
the toes.
Warning! Cotton buds should not be inserted into
ears for any reason other than for collecting
samples. This could lead to damage to the liningof the ear canal and/or push ceruminous material
down toward the tympanic membrane.
Tip: If ear mite infestations are suspected, an
additional slide should be prepared and examined
microscopically, unstained and under low power.
COTTON SWAB SAMPLING
Bacterialovergrowth
Neutrophil with
engulfed cocci
BACTERIAL INFECTION/OVERGROWTH
Interpretation of cytological slides requires some experience and practice. Examine the sample
under high-power x 400 magnification to detect inflammatory cells (mainly neutrophils and
macrophages) and under x 2,000 magnification with oil immersion to detect cocci, rods and yeasts.
Tip: Make sure you don’t confuse cocci (perfectly round, similarly sized and purple in colour)
with melanin granules (black/brown/yellow colour) or irregularly shaped stain aggregates,
when focusing up and down.
INTERPRETING THE SLIDES
Cells (x 400) Yeasts Cocci (x 2,000) Rods (x 2,000)
Making a difference to your day
CANAURAL: Each g of Canaural contains Fusidic acid (diethanolamine fusidate) 5 mg, framycetin 5 mg, nystatin 100,000 units, prednisolone 2.5 mg. UK: POM-V IE: POM FUCIDERM: Fuciderm Gel contains 0.5% w/w Fusidic acid and 0.1% w/w betamethasone valerate. UK: POM-V IE: POM
MALASEB: Malaseb Shampoo contains 2% w/v chlorhexidine and 2% w/v miconazole. UK: POM-V IE: P OM Further informatio n is available on request from: Dechra Veterinary Produc ts Ltd, Cartmel Drive, Harlescott, Shrewsbury, Shropshire SY1 3TB. Tel: +44 (0)1743 441632. Fax: +44 (0)1743 462111.
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