Characteristic of H. Pylori is

Normal duodenum cannot harbour H pylori, duodenum with gastric metaplasia can very well get infected by H pylori which explains why it is involved in duodenal ulcer. It is a gram-negative spiral like flagellated organism, it is most common cause of duodenal ulcer (95%), triple regime including clarithromycin - metronidazole - omeprazole is used for its treatment Reference SRB edition :5 page : 819, 820