For the second instalment of Café Scientifique’s dialogue series, SFU assistant professor Julian Guttman explained how different pathogenic bacteria infect humans, what illnesses they cause, and the ways some bacteria can be used as bioterrorism weapons.
These “talks with docs” are intended as educational, casual discussions between research professionals and the general public and aim to engage the community by connecting them with current research.
Guttman began his chat by bringing recent bacteria-related food recalls to mind — these include the E. coli contaminations in XL Foods beef and at Gort’s Gouda Cheese Farm in Salmon Arm, BC. “When bacteria come up [in conversation], essentially everyone thinks about related human ailments — the diahrrea, the vomiting, and everything disgusting that comes with it,” he notes.
In his research, Guttman examines a variety of pathogens — including E. coli, Salmonella, and Listeria — to discover how they cause diarrhea in infected humans. While it is traditional knowledge that bacteria induce diarrhea through controlling intestinal muscles and membrane ion channels, his lab has found three additional causes of diarrhea. These include breaking the protein junctions between cells, controlling cell water channels to keep excess water in the body, and creating extra communication tunnels in cells.
Listeria, another hazardous bacterium on Guttman’s agenda, kills 30 per cent of infected individuals and is one of the only bacteria able to effectively infiltrate the fetuses of pregnant women.
“Listeria has the ability to cross the blood-placenta barrier that normally stops microbes from getting to the baby,” says Guttman. “It’s a very hard barrier for a microbe to cross, but Listeria has figured out a way to do it. After the fetus is infected, it doesn’t stand much of a chance against the bacteria.”
While a 30 per cent mortality rate is not to be taken lightly, the afflictions of these bacteria are minor compared to bioterrorism-level bacteria like Francisella, Guttman explains. Though rare, this bacterium belongs to the highest category of bioterrorism agents in existence — one microbe, he estimates, is enough to cause full-blown disease in humans.
“We know that Francisella can kill people in about two days to a week,” said Guttman. “You’ll essentially have flu-like symptoms and then die, which is horrible. You would have no idea [what hit you], and that’s exactly what a terrorist would want.”
“Hopefully, we’ll be able find a solution so that people feel more at ease about these bacteria and we can eliminate them off the threat list,” Guttman concluded. “It’ll take a lot of work, though.”