Chapter 1 | Introduction to Special Stains - Dako

Introduction to Special Stains Introduction to Special Stains
Figure 3. Lung stained with Acid-Fast
Bacteria (AFB) Stain, Dako Code AR162.
This AFB stain is suitable for the visualization
of acid-fast bacteria belonging
to the Mycobacterium genus on the
Artisan Staining System. Application of
carbol-fuchsin stains acid-fast bacteria
fuchsia, followed by decolorization of
all tissue elements except the acid-fast
bacteria. A methylene blue counterstain is
then applied to impart a blue color to all
background tissue elements.
Figure 4a. Electron micrograph (EM)
(negative staining) of H. pylori possessing
multiple flagella. Courtesy of Wikimedia.
Prof. Yutaka Tsutsumi, MD, Department of
Pathology, Fujita Health University School
of Medicine, Japan.
Sheathed polar flagella
Body of the Bacteria
Figure 4b. Illustration of S-shaped H. pylori with four sheathed polar flagella. The majority of helicobacters possess this basic morphology of an S-shape with polar,
sheathed flagella, though variations in size and the number of spirals are seen in a number of other species. These bacteria are usually around 0.5 × 5 μm, and the
S-shaped morphology has been correlated with maximum in vitro motility. Thin sections of H. pylori revealed through an electron microscope show an outer and inner
membrane separated by the periplasm of approximately 30 nm thickness (see EM picture above). The dense cytoplasm contains nucleoid material and ribosomes
(Source: Jani O’Rourke and Günter Bode. Morphology and Ultrastructure of Helicobacter pylori. Physiology and Genetics. Eds. Harry L. T. Mobley, George L. Mendz, and
Stuart L. Hazell. ASM Press. 2001). Illustration by Rashmil Saxena, BFA, HT(ASCP) CM .
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