Concordia Public Scholar Laura Domínguez Mercado tackles rising antibiotic resistance

Bacteria are developing resistance to antibiotics faster than new treatments can be developed — with devastating effects. According to the World Health Organization (WHO), antibiotic resistance is one of the top global health threats, contributing to some 4.95 million global deaths in 2019 alone.

Concordia Public Scholar Laura Domínguez Mercado is hoping to develop treatments that slow down the evolution of antibiotic resistance by studying the stress responses of E. coli bacteria.

Domínguez, a PhD student in the university’s Department of Chemistry and Biochemistry, notes that the impacts of unchecked antibiotic resistance are huge. Infections are harder to treat, and other medical procedures and treatments — such as surgery and chemotherapy — are much riskier.

Antibiotic resistance also has significant economic costs. The World Bank estimates it could lead to $1 trillion USD in additional healthcare costs by 2050.

Domínguez’s research is funded by the Fonds de recherche du Québec – Nature and technologies (FRQNT), Fonds de recherche du Québec – Santé (FRQS), Mitacs and Concordia.

‘We can’t stop evolution from happening’

How do bacteria acquire resistance to antibiotics?

Laura Domínguez Mercado: Bacteria live in very harsh conditions, which impose a lot of selective pressure on them. Bacteria also evolve very rapidly. If they are in a stressful environment, a bacterium will randomly acquire a mutation that makes it more apt or able to live in that specific environment. That bacterium will be able to grow better and reproduce.

After some time, bacteria with that beneficial trait will be the most prevalent in the population. That happens with antibiotics as well. Eventually, one bacterium present in an environment with antibiotics will acquire a beneficial mutation. Then, that bacterium will be able to grow while the other ones will die.

What are the main drivers of the global increase in antibiotic resistance?

LDM: Evolution is the main driver of antibiotic resistance. We can’t stop evolution from happening. Even if we had never discovered antibiotics, nor started producing them, antibiotics already exist in nature. Bacteria have been in the presence of antibiotics — and have been evolving ways to resist them — even without our input.

That being said, our overuse and misuse of antibiotics have accelerated the issue. Using antibiotics when they’re not necessary and without a prescription is a huge problem.

Resistance to antibiotics usually comes at a cost for bacteria. A resistant bacterium will be less fit than one that is susceptible because it usually has to expend more energy: for example, to modify or break down the antibiotic.

In the absence of the antibiotic, the bacteria without resistance will grow better, divide better and have more offspring. That’s why we need to avoid using antibiotics unless absolutely necessary.

All the antibiotics used in animals and humans eventually get to the environment. They eventually get to our water reservoirs. The increased presence of antibiotics imposes the selective pressure for bacteria to evolve and maintain resistance.

What can we do to slow down antibiotic resistance?

LDM: The best thing we can do is lower infection rates through better sanitation practices. There’s a big need for global collaboration because the evolution of resistance can happen anywhere. It is more likely to happen in countries where infections are higher and access to healthcare is lower.

The drivers of antibiotic resistance are exacerbated by poverty and inequality. Low- and middle-income countries are most affected.

What do you hope the impact of your research will be?

LDM: I would like to increase our current understanding of how the evolution of resistance happens. Hopefully, that will allow us to create better treatments. By understanding how resistance evolves in the cell, we can create new therapies that will be less prone to the evolution of resistance and more effective for a longer period of time.

As I said before, we can’t avoid the evolution of resistance. The only thing we can do is try to find ways of slowing it down.

Learn more about Concordia’s Public Scholars Program.