 Helicobacter pylori H.pylori is a small, Gram-negative spirochete inhabiting the mucous layer overlying the gastric epithelial cells in humans. It is the most common prevalent chronic human bacterial infection and the most common cause of gastritis worldwide;. Furthermore, according to the World Health Organization, HP is classified as a type 1 carcinogen and is the primary cause of peptic ulcer disease, gastric carcinoma, and mucosa-associated lymphoid tissue lymphomas . 