Tissue containing Helicobacter pylori is a satisfactory control for which modification of Giemsa staining?

• A. Diff-Quik Giemsa modification
• B. Gram stain modification
• C. Wright-Giemsa modification
• D. Ziehl-Neelsen modification

Answer: (A)

Using tissue known to harbor Helicobacter pylori as a positive control is most appropriate with the Diff-Quik Giemsa modification. This rapid Romanowsky-type stain reliably highlights H. pylori in gastric mucosa, staining the bacteria dark blue to purple against a lighter background. The result is a clear, characteristic appearance that confirms the staining procedure and reagent performance, including fixation, deparaffinization, and stain timing. Helicobacter pylori are small, curved, Gram-negative rods that stand out with this stain, making it an effective check of the technique.

Other modifications are less suitable for this purpose. Ziehl-Neelsen targets acid-fast organisms and is not the standard method for visualizing H. pylori in tissue. Wright-Giemsa is primarily used for blood and marrow smears, not routine tissue demonstration of H. pylori. Gram stain modifications are less consistent for detecting H. pylori in fixed tissue.