General purpose of this lecture is to present on Bacteria Ulcers. Helicobacter pylori is a type of bacteria. H. pylori is a common type of bacteria that usually infects the stomach. These germs can enter your body and live in your digestive tract. After many years, they can cause sores, called ulcers, in the lining of your stomach or the upper part of your small intestine. For some people, an infection can lead to stomach cancer.