The characteristics that determine if, where and how a bacteria causes a disease are called virulence factors.
In the case of H. pylori, these virulence factors include
- Flagella which allows motility and enables it to colonize under the usually protective layer of gastric mucous
- .Production of exotoxins and secretory enzyme that damage the gastric mucosa.
- a secretion system which enables injection of chemicals into gastric cells
- production of urease which produces ammonia which decreases the acid pH of the stomach. This is a critical virulence factor which is unique to H. pylori.