Helping prevent outbreaks of pathogenic Clostridium difficile is the goal of an innovative partnership between the University of Guelph and Guelph General Hospital (GGH).

The collaboration reunites a U of G professor and his former graduate student in combating the toxin-producing bacterium.

Scott Weese, a pathobiology professor in U of G’s Ontario Veterinary College (OVC) and a leading researcher on C. difficile and infection control, is working on the project with Devon Metcalf, infection prevention and control professional at GGH.

Metcalf worked with Weese as a PhD student and post-doctoral researcher – focusing on C. difficile — and was the OVC Health Care Centre’s infection control practitioner in 2012-2013.

In 2014, she joined GGH, where she sought to learn more about how C. difficile spread in hospitals. A study in the United Kingdom found various strains involved in hospital outbreaks, suggesting that some patients might have brought C. difficile into the facility rather than acquiring it there.

Metcalf contacted Weese about conducting a similar analysis in Guelph.

C. difficile can overpopulate the human colon, particularly when antibiotics kill healthy gut bacteria. C. difficile infection causes many gastrointestinal problems, including severe diarrhea, and often leads to outbreaks in hospitals and long-term care facilities.

There are hundreds of thousands of C. difficile cases each year in the United States and Canada.

It is a common assumption that patients acquire the bacterium mostly in hospitals and long-term care facilities after antibiotic therapy and that the bug causes most diarrhea outbreaks in hospitalized patients.

For the past 10 months, Weese and Metcalf have studied bacteriafrom GGH patients with C. difficile infection to see whether the cases are linked or have different sources.

“For example, if there were three C. diff cases on a ward, you’d assume they were all related. However, if we type them and find three different strains, they’re not linked, and that means something different is happening,” Weese said.

“It’s important to sort it out because you have to know what going on in order to figure out what the intervention will be. You may get a cluster of cases in a hospital, and how you manage them may be different depending on whether it originated in the hospital or if they contracted it in the community before coming to the hospital, and that is the big question to answer.”

Preliminary analysis shows diverse infection-causing strains in hospital patients.

“Patients are not always sharing the same strain — it really associates with the theory that perhaps patients are coming into the hospital with the strain,” Metcalf said.

As testing is ongoing, Metcalf and Weese said it’s too early to speculate about outcomes. But they said the research could have an effect on prevention and containment, including outbreak declarations and other response measures.

“This work has allowed us to understand that C. difficile outbreaks may not always be a result of transmission between patients,” said Metcalf. “There might be other factors involved. This work allows us to focus on interventions that may be more likely to reduce the number of infections we see.”

Why did a human hospital reach out to a veterinary teaching hospital for assistance?

“My lab focuses on infectious disease, not veterinary infectious disease, and we started working with C. difficile before it was recognized as a major problem in people.  A bug is a bug. It doesn’t matter if C. diff is coming from a horse or a person or a dog – it’s the same bug,” said Weese.

He has studied the bacterium for nearly 20 years and has worked with public health agencies to help assess and manage infection and disease risk.

“There was a big void in C. difficile research — no one doing it much, so I sort of worked my way into the human side.”

As the holder of the Canada Research Chair in Zoonotic Diseases and interim director of U of G’s Centre for Public Health and Zoonoses, Weese studies how diseases spread from animals to humans. His Worms & Germs blog and disease-mapping site both help raise awareness of these infections among veterinarians, healthcare providers and the public.

For media questions, contact:

Lori Bona Hunt, News Service Director, University of Guelph, 519-824-4120, Ext. 53338 or

Perry Hagerman, senior communications specialist, Guelph General Hospital, 519-837-6440, Ext. 2774 or