Who was awarded the Nobel prize for the discovery of Helicobacter pylori?

Helicobacter pylori is a bacteria that causes peptic ulcers in humans. 

Barry Marshall and Robin Warren were the two pioneers in biology who were awarded the Nobel Prize (2005) in Medicine. They discovered that peptic ulcers were caused by an infection with Helicobacter pylori. With this discovery, peptic ulcer disease is now curable and requires a short period of treatment with antibiotics.