A deadly outbreak of C. difficile in southern Ontario is raising the ire of frustrated locals who say that the province's health system isn't doing enough to halt the bacteria's spread.

The bacteria has been linked to more than a dozen deaths in the region since late May. Dozens more have been infected.

More than 40 patients in hospitals in Niagara Falls, Welland and St. Catherines have been in seclusion this week.

Recently, an outbreak was declared at Guelph General Hospital after a spike in the number of cases through May and June. While there are usually one or two cases each month at the hospital, there were seven incidents in May and another four in June.

In the Niagara area, officials are grappling with a larger outbreak that has been linked to an estimated 16 deaths and 63 infections. The outbreak caused officials to shutter the emergency room at the Greater Niagara General Hospital recently.

On Wednesday, about 100 demonstrators gathered at the Niagara facility to say that it took far too long for officials to warn the public about the outbreak.

Some carried signs reading "Right to know," and "Third World health care? You must live in Niagara."

C. difficile is generally characterized by the onset of severe diarrhea, but can lead to more serious symptoms.

"The complications unfortunately can lead to surgery, intensive care unit admission, and at times, death," said Doug Sider, Ontario's acting director of infection and disease control.

Relatives affected by the bug have also demanded more transparency from health officials.

The outbreak was declared on June 23 after several deaths had been reported -- too little, too late, according to some.

Ontario NDP Leader Andrea Horwath is calling for a public inquiry into the ordeal, and she blamed overcrowding at hospitals for contributing to the deaths and infections.

"You can't cut back and cut back and then expect things to go well in terms of your health system," she said Wednesday.

Horwath also blamed cleaning staff cutbacks for the spread.

The regional health authority has said that it's working hard to contain the problem, and provincial officials say teams of experts are taking part in the battle against the bacteria.

"What is important to the minister right now is that everyone is working together to manage this outbreak," said Neala Barton, a spokesperson for Deb Matthews, Ontario's health minister.