Scitech | Tall Tails of Bacteria

Using cranberries to ward off infections

Tails, or flagella, are what allow bacteria to migrate in groundwater, contaminate hospitals, and colonize the human body. Bacteria are the source of many diseases and can spread like wildfire. The key to their success is their ability to rapidly migrate. This process is called swarming, and is currently under investigation by Nathalie Tufenkji, a professor in McGill’s Chemical Engineering department.

Tufenkji explains that “by improving the understanding of [microbial interactions with their environment], we can develop improved medical devices, water treatment processes, and soil remediation technologies.” Her latest work focuses on the antibacterial properties of cranberries.

The story starts with implanted medical devices, the practicalities of which are immense: they decrease the number of hospital visits, cut costs, and save time, all of which ultimately allows patients to lead more typical lives. Examples of these devices include catheters, hip replacements, heart valves, implanted ocular lenses, and even contraceptive devices.

Still, implanted devices present a number of problems. “Infections resulting from contaminated indwelling devices are initiated by bacterial adhesion to the device surface,” Tufenkji reported to The Daily, “leading to risk of infection or device failure.” Catheter-associated bacterial infections are the most common form of hospital-acquired infections.

The trick is to stop bacteria from spreading by targeting flagellar transport. In the process of infection, some bacterial strains can manufacture thousands of flagella to swarm and migrate to surfaces such as medical devices. Tufenkji is currently working on developing or modifying materials that deter bacterial attachment, to replace the often ineffective or costly ones used today.

Cranberries have been traditionally used to treat and prevent urinary tract infections, which are often caused by the microbe Proteus mirabilis. The active chemical in cranberries has not been identified by scientists to date, but cranberries themselves have been shown to hinder bacterial attachment to surfaces and impair bacterial motility. Tufenkji’s efforts revealed that cranberry-derived materials (CDMs) critically interfere with flagellar production by decreasing the amount of the protein (called flagellin) required. This renders the bacteria immobile, preventing swarming and spreading.

This summer, Tufenkji incorporated the CDMs into the silicone used to make catheters. The experiment proved to decrease the production of flagellin in both E. coli and P. mirabilis, thus inhibiting their motility (ability to move spontaneously and accurately) and preventing the spread of infection. This suggests that treatment for these types of bacterial infections may not be needed if incorporation of these substances into biomedical materials is an effective prophylactic.

The creative application of traditional methods to modern medicine is invaluable. Tufenkji’s work constitutes another convincing argument for the creative application of traditional treatments in modern medicine.