Sophia Kathariou is the kind of scientist who can turn food-borne bacteria into great dinner conversation.

The associate professor of food science and microbiology at N.C. State University in Raleigh, N.C., spoke about her work Thursday night at Mitch’s Tavern, a longtime haunt for professors and students alike. The talk was one of Sigma Xi’s Science Cafés, which aim to promote science among the public.

Over local craft brews, Greek salads and gumbo, Kathariou was quick to mention the softer side of bacteria. Whether we hear about them "attacking our immune system" or "weakening our defenses," she said the militaristic tone of communication about microbes has to change.

"Society has been trained to think about microbes and bacteria as enemies. This could not be further from the truth," she said. "They are part of who we are and what we do."

Symbiotic microorganisms in the digestive tract, for example, edge out the more harmful ones that would normally make people sick. Probiotic supplements are even supposed to increase the role these "good bacteria" play in the gut, a claim that prompted questions from one of the audience members. Although Kathariou said it’s always possible to have too much of a good thing, some data have shown probiotics can promote better function of the immune system.

"In my interpretation, they don’t hurt," Kathariou said.

But there are plenty of microbes that do cause harm. That’s why Kathariou said the overuse of antibiotics is increasingly becoming a problem. While organisms often obtain their genes through biological parents, or vertical transfer, many microbes are able to adapt and mutate through horizontal transfer -- simply swapping bits of DNA with each other. Because nature allows for that rapid change in genetic material, Kathariou says patients should avoid "self-medicating the ghost."

"We don’t always get just what we target," she said.

What’s important, Kathariou said, is that we continue to learn more about microbes not just in terms of what they do to us, but what they do for us. She said gaining a better understanding is critical to figuring out how to live with these bacteria – just as it would if you were dealing with a problem child or a bad marriage.

"If you don’t know the person, you can’t solve the problems," she said.

That attitude has already helped scientists paint a better picture of the microscopic world. Like humans, for example, bacteria behave differently in small groups than in large ones.

"If bacteria are in low numbers, they’re not going to be doing the same things as a large biomass," Kathariou said. "Some things they do are highly dependent on numbers."

Proximity to such a tipping point might determine factors like whether harmful bacteria release toxins. And that makes sense to Kathariou from a survival standpoint.

"They don’t want to be producing stuff and wasting it if it’s not going to cause an illness," she said.

But as Kathariou pointed out to her audience, humanity worked to increase its knowledge of microbiology long before it was established as a scientific discipline. Preventing diseases like botulism, which can be caused by an anaerobic bacterium in food, prompted societies to learn preservation techniques like smoking and curing.

"All cultures learned by trial and error to avoid foods that cause disease," Kathariou said. "They find them repulsive."

After about an hour of conversation on putrid food, fatal disease and beneficial gut flora, the bar settled back to its normal Thursday night bustle. Judging from the constant stream of questions during the talk, there was certainly interest from the crowd. That’s not surprising to Jennifer Larese, who coordinates similar Science Cafés with WGBH Boston.

"We’ve found lots of people are interested in asking questions, but don’t want to feel silly," Larese said. "This gives them a casual, comfortable place to do that."

Café organizer Elsa Youngsteadt, with Sigma Xi, said she was happy owner Mitch Hazouri jumped at the chance to host the discussion in his tavern.

"I thought that no venue would want to have this talk," she said with a grin.


Cross-posted on Science In The Triangle


Images: Sophia Kathariou talks microbes to a crowd at Mitch’s Tavern in Raleigh.| Photo by Tyler Dukes. Special thanks to Rob Fisher for the photo editing help!


About the Author: Tyler Dukes is a freelance science writer and full-time journalism adviser at N.C. State University. Follow him on Twitter as @mtdukes.




The views expressed are those of the author and are not necessarily those of Scientific American.