The exact mode of transmission of H. pylori is unknown as of 2015, according to Mayo Clinic, so there is no one best way to catch it. However, it is likely transmitted by person-to-person contact, either through saliva, vomit or feces, or through dirty food and water.
According to Dr. Otis Brawley of the American Cancer Society, people with H. pylori are more likely to have family members who are also infected with the bacteria, which suggests person-to-person contact is the most common form of transmission. However, H. pylori also may be transmitted by swimming in or drinking contaminated water, and from contact with infected animals.
Although there is no best way to catch H. pylori, there are best practices to avoid it, according to WebMD, namely by washing hands after using the bathroom and before preparing food, avoiding unclean food and water, or food that is prepared by those who have not washed their hands, and avoiding foods that are not cooked thoroughly.
Most people infected with H. pylori have no symptoms, states Mayo Clinic, while others can experience abdominal pain, nausea, burping, bloating, loss of appetite and weight loss. The bacterial infection may lead to inflammation of the stomach lining, ulcers and stomach cancer.