Five-reagent kit for staining Spirochaeta, Helicobacter pylori, Microsporidia and Legionella pneumophila. The kit contains 12 jars with gelatine that enables both incubation and staining of sections, as well as other reagents that enable precipitation of silver on the bacterial surface. The bacteria are found in the mucus of the surface epithelium, in the apical gastric glands and in the gastric mucosa.