Helicobacter pylori are spiral-curved, gram-negative
bacteria that can infect the surface epithelium of the mucous layer of the
stomach. There is evidence showing that these bacteria may play a significant
role in peptic ulcer disease. Immunohistochemical techniques can distinguish
Helicobacter pylori from other types of bacterial infections. This small
spiral-curved shaped bacterium can be clearly seen using a 100X oil
objective.