Page 237 - The Veterinary Laboratory and Field Manual 3rd Edition

206 Susan C. Cork and Roy Halliwell

Table 4.1 continued

Stain Specimen and some of the Appearance in stained sections
organisms that might be seen
Modified Ziehl-Neelsen Vaginal exudate, placental material
(or Ziehl-Neelsen acid-fast) Brucella spp. Small red coccobacilli in clumps
Purple-pink to red colour (acid
fast = red) Chlamydia spp. Small red coccobacilli in clumps
Lymph node, intestinal and
Carbol fuchsin stain generalized
penetrates the bacterial Mycobacterium paratuberculosis Fairly short, red ‘acid fast’ rods in
cell wall and is retained clumps
after decolorisation
leaving Mycobacteria spp. Mycobacterium bovis Long thin bright red rods, may
characteristically red appear beaded, usually few present
Mycobacterium tuberculosis Long thin bright red rods, usually
few present
Giemsa or methylene blue Blood smear from ear vein or
Pink-purple or Purple-blue body fluids
Bacillus anthracis Purplish or blue square ended rods
Polychrome methylene blue in short chains surrounded by a
is often used to stain slides pinkish or red capsule. May also
with suspected anthrax – see spores.
Bacillus anthracis stains
characteristically blue with Skin preparations and tissue smears
distinctive pink capsules Dermatophilus congolensis, rickettsiae and Borrelia sp. stain blue with
Giemsa

Unstained wet preparations Hair, skin and scabs
Ringworm fungi **** Chains of refractile, round
(Trichophyton sp.; Microsporum arthrospores on hairs
spp.)
Other fungi (high dry objective) Fungal mycelial elements or
budding yeast cells
Eye fluid, urine
Leptospira spp. Elongated thin, helical structures
with hooked ends, difficult to see
without dark field microscopy
Vaginal smear
Trichomonas spp. Protozoan with undulating
membrane and four flagella

Notes: *Cocci = circular. **Rods = elongated (some may be cocco-bacilli, these are elliptical in shape). ***Corynebacterium
spp. can be quite variable in shape (pleomorphic) and may be rods, cocci, club shaped or filamentous. **** The Lactophenol
cotton blue stain can also be used; *****The Azur B stain can also be used to identify Bacillus anthracis in blood smears. The
main advantage compared to the Polychrome methylene blue staining is that Azure B stain (Aldrich 227935-5G) will be ready
for use immediately after preparation. Storage can be at room temperature in a dark container or dark area. The shelf life is at
least 12 months.

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