Research in Action: - University of Calgary

The next generation of antibiotics must be able to target hospital-acquired infections and chronic illness,
says U of C microbiologist Dr. Howard Ceri, a professor in the Faculty of Science and chairman of the
Biofilm Research Group. But traditional methods of testing won’t tell us how to fight bacteria growing on
medical implants or in urinary catheters. All antibiotics on the market today have been tested on bacteria
grown in broth suspensions, explains Ceri. But in the real world, bacteria tend to stick together, forming
organized slime layers called biofilms on metals, plastics, body tissues or any other available surface.
Fighting infection on
medical devices
Biofilms are not just an interesting scientific phenomenon—in developed countries, biofilms cause most
bacterial infections and about 90 percent of infections picked up in hospital. Biofilms are also extremely tenacious,
and are able to withstand concentrations of disinfectants or antibiotics that would wipe out free-living microbes.
Ceri and his colleagues around the world are evaluating the first wave of new therapies to fight these biofilms,
using a device developed by Calgary’s Biofilm Research Group, co-founded by Ceri and other Calgary
researchers in the mid-90s. The device, which is commercialized as the MBEC Assay and licensed to
Innovotech Inc., is a plastic, multi-well tray the size of an outstretched hand. With this tool, researchers can
study 96 miniature biofilms at once, allowing for rapid testing.
Prototype product developed
Recent U of C PhD grad Joe Harrison used the MBEC Assay to test the tolerance of bacterial biofilms to
toxic metals and other antimicrobials. Already the research has led to a prototype product that could be used
to disinfect hard surfaces in hospitals. Harrison has tried to find out what is happening in the biofilm to make
it tolerant to metals. He thinks that the answer lies in the way that the bacterial cells take on specialized roles
in the biofilm population. Like people, the bacteria are community members that communicate and interact
to the benefit of the group.
Ceri is particularly interested in biofilms that grow on medical implants, such as artificial hips and heart
valves. Up to about five percent of recipients develop implant-related infections. Many of these patients must
undergo additional—and typically less successful —replacement surgeries. In some cases, the infection kills.
A focus of Ceri’s current research is antimicrobial coatings for medical implants to keep biofilms at bay. Thus
far the work has generated a patent application for a novel coating.
ucalgary.ca/~ceri/brg/
innovotech.ca/index.php
18 UofC Research in Action
Dr. Howard Ceri’s understanding
of biofilms will help fight infections
on medical implants like artificial
hips and heart valves.