The recent paper by Rotimi and colleagues¹ does not mention the acridine orange stain² when comparing staining methods for the identification of Helicobacter pylori. The acridine orange stain uses ultraviolet fluorescence in the identification of bacteria. The typical curved morphology of H pylori can easily be differentiated from other bacteria.^3–5 I have used this quick, cheap, and reliable stain in routine histopathology reporting for over 16 years and it has proved to be extremely useful in the identification of H pylori.

Immunohistochemistry is now recognised as the “gold standard” because it is a highly sensitive and specific staining method.¹ After the publication of the above mentioned article, 20 consecutive gastric biopsies that were positive for H pylori using the acridine orange stain were also stained using the polyclonal anti-H pylori antibody (Dako, Ely, Cambridgeshire, UK) at a dilution of 1/100. Twenty negative control cases were similarly studied. All 20 cases that were positive with the acridine orange stain were also positive by immunohistochemistry and all negative cases were …