Diagram 2: Features of H. pylori

H. pylori — so-named because of its shape
and where it is found — is spiral shaped when it is actively
growing and invading the epithelial cells of the stomach
and duodenum. The bacteria use their spiral shape and
flagella to move through the mucus of the stomach, which
is present to protect the cells against the hydrochloric acid
and enzymes that break down ingested food. The mucus
also protects the bacteria against the effects of the acids.
H. pylori that do not have flagella are unable to colonise
the epithelial cells and cause ulcers.