Emily Vis

If you have a healthy gastrointestinal tract, you can thank your gut bacteria for keeping things running smoothly. Researchers in the Department of Molecular and Cellular Biology are looking at ways of extending the beneficial effects of probiotic bacteria by keeping them in the gut for longer periods of time. Since these bacteria don’t usually stay in the body for more than 24 hours, they need to be consumed on a daily basis to keep their numbers up.

“What we’re trying to do is enhance their retention in the gut by gut biofilms found in the mucosal linings throughout the gastrointestinal tract,” says master’s student Emily Vis. She is using microscopy to characterize various probiotic strains, and study their surface structure, motility and their ability to form bacterial communities.

“It’s very hard to mimic gut conditions,” says Vis. “It’s extremely expensive to do.” The lab grows bacterial samples in a medium and adds mucin, one of the main components of mucous, and prebiotics, which are indigestible for humans but enhance bacterial growth and biofilm formation. Engineering bacteria to express certain motility genes and proteins may improve their ability to form biofilms.

The health benefits of probiotic bacteria go beyond promoting regularity, says Vis. Researchers believe they displace pathogens, which may help prevent infections and various types of diarrhea, including those caused by rotavirus, traveller’s diarrhea and antibiotic-induced diarrhea. “A lot of people suffer from it because antibiotics kill all the beneficial bugs in your gut,” says Vis.

Eating yogurt boosts the probiotic bacteria population in the gut, but only temporarily, she adds. Yogurt may contain 1010 probiotic bacteria, but depending on how long it’s been sitting in your fridge, many of the bacteria may have died by the time you eat it because of less than ideal living conditions or a shortage of nutrients. Supplements are another source of probiotic bacteria.

“You’ve got to take in a very large amount of these bacteria in yogurt or probiotic supplements to see the effects,” says Vis. Not all probiotic bacteria are created equal; some are more beneficial than others. The health effects depend on ingesting the right amount of certain bacterial species and strains.

Once ingested, the bacteria need to contend with the acidic environment of the stomach before entering the intestines. Many of the bacteria don’t survive the journey. Ideally, these bacteria should stay in the body for as long as possible so that people can reap the most health benefits.

“The longer the better,” says Vis. People with irritable bowel syndrome, she adds, need to consume trillions of probiotic bacteria per day as part of their treatment, which can be costly and inconvenient. The research could lead to a pill containing bacteria that last longer in the body.

Vis says bacteria are often misunderstood because they only get media coverage when they cause disease outbreaks and deaths. Only a small percentage of bacteria are harmful to humans. “I don’t think the beneficial bacteria are looked at as much as they should be,” she says. “Most people look at what’s bad about bacteria, but there are so many bacteria that are good for you. We’d be in a much worse place without bacteria.”