Health officials in Southern Ontario may have found a common thread in separate E. coli outbreaks in the area.

The bacteria were found in both Halton and Niagara regions, and now, researchers claim, they have found similarities in the strains. They seem to show a common "fingerprint."

Three restaurants in Burlington, Niagara-on-the-Lake and Welland are closed as officials are investigating 41 possible E. coli cases. Of those, 11 have been confirmed.
  
In four of five suspected cases, the people ate at Johnathan's Family Restaurant in Burlington. It has since been closed for the investigation. The other two restaurants involved are Little Red Rooster in Niagara-on-the-Lake or M-T Bellies Tap and Grillhouse in Welland.

One person was hospitalized but has since been released.

The Health Departments in both regions are working together to find the link, and they think it might be a restaurant-grade food supplier.

"We are trying to track through the supply and the source of the foods ... we're not just looking at the restaurants (involved) we're also looking at the cross-link between distributors," confirmed Dr. Robin Williams, medical officer of Health for Niagara Region.

So far 208 food samples have been taken from those restaurants for analysis.

It is not connected to the outbreak in North Bay.