Antibiotics and E. coli: Concordians publish research with major implications for public health

Antibiotic-resistant bacteria is a major threat to global health. In the United States alone, it accounts for 23,000 deaths each year, according to a 2013 report from the Lancet Infectious Diseases Commission.

The Review on Antimicrobial Resistance estimates the global death toll will reach 10 million per year by 2050 if no action is taken.

However, research by Brandon Findlay, assistant professor in the Department of Chemistry and Biochemistry in Concordia’s Faculty of Arts and Science, could lead to profound changes in how the strength of existing antibiotics is measured and how new ones are tested against E. coli, with implications for other bacteria.

The research, co-authored with undergraduate students Nour Ghaddar and Mona Hashemidahaj and published last month in the open access journal Scientific Reports, demonstrates major strides in antibiotic susceptibility testing.

‘A clearer picture of how E. coli are developing resistance’

The Concordia team built a low-cost bacterial evolution chamber — called a Soft Agar Gradient Evolution or SAGE plate — and used it to evolve strains of E. coli resistant to every major class of antibiotics.

“The main principle of the SAGE plate is having a nutrient-rich semi-solid gel that E. coli thrive in. The catch is that it contains an increasing concentration gradient of the chosen antibiotic,” says Ghaddar, who recently graduated with a BSc honours in Biochemistry.

“This mimics the way antibiotics work inside the human body. As the bacteria swim in search of nutrients, they encounter an increasing concentration of antibiotic, forcing them to develop mutations in order to survive.”

Antibiotics are often evaluated by putting bacteria on a petri dish with the antibiotic, counting the bacterial survivors and performing a bit of complex math to estimate if resistance will evolve during treatment.

“Our SAGE plate method provides a clearer picture of how E. coli are developing resistance,” Ghaddar says. “And, as a result, it can better inform how we test, prescribe and develop antibiotic treatments.”

This method also gives insight into whether resistance will happen quickly or slowly over time, an important component in the choice of antibiotic and determining the length of treatment.

“By understanding the factors behind how bacteria mutate in order to survive, we can design drugs that retain their strength longer, which could lead to more successful treatment for patients,” Findlay says.

‘Bringing science out of the lab and into the class’

The paper’s results speak to the reliability of the SAGE system and open up opportunities for more people to run similar experiments. Because of its low cost, anyone with bacteria culturing experience can build their own using everyday lab wear.

Findlay was inspired by equipment at the University of Texas, Austin, but after looking into how to build something similar, he found the price and the timeline prohibitive. Using lower tech components, he was able to create the SAGE plate system.

“The technique is simple enough that I could imagine high school or CEGEP students running similar experiments,” Findlay says. “Bringing science out of the lab and into the class can help demystify what we do and potentially inspire the next generation of researchers.”

Hands-on experience in a ‘non-competitive environment’

Both Ghaddar and Hashemidahaj found the experience gave them a unique opportunity to put their learning into action.

“It was amazing and very intense,” says Hashemidahaj, a recent graduate with a BSc specialization in Cell and Molecular biology. “I walked away with not only more experience and confidence, but with my name as co-author on a published paper.”

Ghaddar, who participated in the project as part of the Concordia Undergraduate Student Research Awards Program, says she felt motivated and supported by her professors and fellow students.

“Undergraduate students are really encouraged to volunteer, work and initiate projects in research labs, which I really appreciated,” she says. “Professors are always available to guide and help students and I enjoyed the non-competitive environment — we all helped each other and discussed our findings as a group.”

Findlay adds that it is rare for students to co-author a paper of this kind so early in their post-secondary education.

“It’s unusual for any undergraduate to be listed as an author — let alone two — and as first author. It’s a real testament to Nour and Mona’s skills.”
 

Read the full journal article: Access to high-impact mutations constrains the evolution of antibiotic resistance in soft agar.

Find out more about Concordia’s Department of Chemistry and Biochemistry and the Department of Biology.