Can microplastic fuel antibiotic resistance? Study answers

Microplastics have made their way up food chains, accumulated in oceans, clustered in clouds and on mountains.

In a startling discovery, a team of Boston University researchers found that bacteria exposed to microplastics became resistant to multiple types of antibiotics commonly used to treat infections.

The rate of antibiotic resistance on the microplastic is high compared to other materials.(Shutterstock)

Microplastics - tiny shards of plastic debris - are all over the planet. They have made their way up food chains, accumulated in oceans, clustered in clouds and on mountains, and been found inside our bodies at alarming rates.

Scientists have been racing to uncover the unforeseen impacts of so much plastic in and around us.

One possible, and surprising, consequence: more drug-resistant bacteria.

They say this is especially concerning for people in high-density, impoverished areas like refugee settlements, where discarded plastic piles up and bacterial infections spread easily.

The study is published in Applied and Environmental Microbiology.

Findings of the study:

"The fact that there are microplastics all around us, and even more so in impoverished places where sanitation may be limited, is a striking part of this observation," says Muhammad Zaman, a Boston University College of Engineering professor of biomedical engineering who studies antimicrobial resistance and refugee and migrant health.

"There is certainly a concern that this could present a higher risk in communities that are disadvantaged, and only underscores the need for more vigilance and a deeper insight into [microplastic and bacterial] interactions."

It's estimated that there are 4.95 million deaths associated with antimicrobial-resistant infections each year. Bacteria become resistant to antibiotics for many different reasons, including the misuse and overprescribing of medications, but a huge factor that fuels resistance is the microenvironment - the immediate surroundings of a microbe -- where bacteria and viruses replicate.

At Boston University (BU), researchers rigorously tested how a common bacteria, Escherichia coli (E. coli), reacted to being in a closed environment with microplastics.

"The plastics provide a surface that the bacteria attach to and colonize," says Neila Gross (ENG'27), a BU PhD candidate in materials science and engineering and lead author of the study.

Once attached to any surface, bacteria create a biofilm -- a sticky substance that acts like a shield, protecting the bacteria from invaders and keeping them affixed securely.

Even though bacteria can grow biofilms on any surface, Gross observed that the microplastic supercharged the bacterial biofilms so much that when antibiotics were added to the mix, the medicine was unable to penetrate the shield.

"We found that the biofilms on microplastics, compared to other surfaces like glass, are much stronger and thicker, like a house with a ton of insulation," Gross says. "It was staggering to see."

The rate of antibiotic resistance on the microplastic was so high compared to other materials, that she performed the experiments multiple times, testing different combinations of antibiotics and types of plastic material.

Each time, the results remained consistent.

Gross and Zaman say that the next step in their research is to figure out if their findings in the lab translate to the outside world.

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.