Australian Nobel Prize laureates Professor Barry J. Marshall and Professor Robin Warren discovered Helicobacter pylori (H. pylori) bacteria to be the cause of cause of stomach ulcers.
A new study of about 850 people found that women infected with the bacteria were less likely to have Multiple Sclerosis (MS) than women not infected.
But men are three times less likely to develop the autoimmune disease compared to women.
Infections like H. pylori could move the balance of the immune system to a less inflammatory state, and as a result the risk of immune sensitivity is reduced, as are the chances of developing autoimmune disorders like MS was the hypothesis of the authors.
Previous studies have investigated the possibility of a link between H. pylori and MS, but used relatively small numbers of people and produced inconsistent results.
The study used blood and clinical information from a database of the state's registered MS sufferers, which was created 18 years ago.
Allan Kermode, Research leader clinical Professor, Neuroscience Research Institute said, "The results from this research may indicate that H.pylori has a protective effect against MS and also bolsters evidence for the role of the hygiene hypothesis in autoimmune diseases."
The hygiene hypothesis suggests that early life exposure to infections may aid the human immune system by priming it, making the development of allergies and autoimmune conditions later in life less likely.
Researchers hope the discovery could pave the way for creating drugs that imitate the effect of the bacteria and prevent MS from developing.
"This research gives hope to the people living with MS and their families," chief executive Marcus Stafford said.