Researchers have mapped where pathogenic Helicobacter pylori colonies live in the stomachs of mice. The scientists report that a small number of bacteria can start colonies in the gastric glands and then expand to nearby glands.
C. Fung et al., “High-resolution mapping reveals that microniches in the gastric glands control Helicobacter pylori colonization of the stomach,” PLOS Biol, doi:10.1371/journal.pbio.3000231, 2019.