Ulcer-causing bacteria have been shown to play a role in stroke.
The bacterium Helicobacter pylori has already been shown to increase the risk of heart disease, perhaps by causing inflammation in the arteries. Now researchers in Rome report that the bacterium may also promote strokes caused by blood clots blocking the arteries that serve the brain.

They studied 138 patients with large-vessel stroke - the type caused by a blood clot - and 61 with cardioembolic stroke, which is caused by a sudden vessel blockage. These patients were compared to a group of healthy people. Nearly half of those in the large-vessel stroke group had a specific strain of Helicobacter pylori in their blood, compared with around 20 per cent in the other two groups. This strain produces a toxin which, the researchers think, may damage the inner lining of the blood vessels, possibly promoting the formation of a clot. More research is needed, but it is possible that treatment of infection with Helicobacter pylori might help to prevent strokes caused by blood clots.