Microplastics in the Environment May Fuel Antibiotic Resistance

Among the plastics tested, polystyrene promoted the highest level of antibiotic resistance.

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Microplastics in the environment may make bacteria harder to kill, a new study suggests.

The study, published in Applied and Environmental Microbiology by researchers from Boston University, found that bacteria exposed to microplastics develop resistance to multiple antibiotics commonly used to treat infections.

The Centers for Disease Control and Prevention has called antibiotic resistance “an urgent global public health threat.”

Bacteria Become Shielded Against Antibiotics

Researchers studied the common bacteria Escherichia coli and found that the microplastics in laboratory environments provided a place for bacteria to stick to and form protective layers that shield them against antibiotics.

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These biofilms act like shields, making it difficult for antibiotics to penetrate and effectively combat the bacteria, according to lead study author Neila Gross, a doctoral candidate in materials science and engineering at BU. “The biofilms on microplastics, compared to other surfaces like glass, are much stronger and thicker, like a house with a ton of insulation,”

The study found that bacteria attached to microplastics and formed biofilms developed significantly higher resistance than free-floating bacteria. Biofilm cells had more than 150-fold increases in antibiotic resistance over a 10-day period.

All bacteria growing inside these biofilms could easily exchange and reproduce resistance genes if they are present, and some antibiotics may have difficulty penetrating biofilms for effective treatment, Infectious Disease Society of America spokesperson Dr. Jasmine Marcelin, an associate professor at the University of Nebraska Medical Center, told The Epoch Times.

Among the plastics tested, polystyrene promoted the highest level of antibiotic resistance compared to polyethylene and polypropylene.

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The researchers suspect that microplastics may intentionally lead to the growth of bacteria that can grow more biofilms. Since when they removed microplastics from bacteria, the bacteria continued to have high biofilm growth.

Microplastics also have special properties that allow antibiotics to stick to them, so the bacteria would constantly be exposed to a low level of antibiotics, thereby enhancing their resistance.

A Need to Address Plastic Pollution

The researchers pointed out that people in impoverished regions may be more susceptible to bacterial infections due to increased plastic waste in their environments.

“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,” study coauthor Muhammad Zaman, professor of biomedical engineering at Boston University (BU), said in a statement.

As plastic pollution increasingly affects developing nations, the resultant antibiotic-resistant pathogens are very likely to travel worldwide, as citizens of developing nations with access to mass transportation such as air and rail visit other countries.

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An estimated 4.95 million deaths worldwide each year are linked to infections caused by antibiotic-resistant bacteria. The World Health Organization calls the growing problem of antibiotic resistance one of the world’s most critical health threats.

The risks of microplastic pollution are serious, particularly as microplastic pollution continues to grow, Dr. Paul Savage, founder and CEO of MDLifespan, a company that provides precision health services, told The Epoch Times.

Emerging evidence links these particles to long-term health consequences, such as chronic inflammation, hormone imbalances, and infections, “though more research is needed to fully understand their impact,” he added.

Addressing the Plastics Problem

Zaman, who also directs the Center on Forced Displacement at Boston University, pointed out that people who don’t use antibiotics as prescribed usually set the blame on antibiotic resistance—however, where people live also matters. Those who live in polluted environments are exposed to more resistant infections through no fault of their own, he noted.

Marcelin said that while the issue with microplastics is serious, an essential approach to addressing antimicrobial resistance must consider the current overuse of antibiotics contributing to the problem.

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“The most important drivers of antimicrobial resistance today are antibiotic misuse and overuse in humans and agriculture,” she said. “Therefore, in order to effectively slow or stop the public health threat of antimicrobial resistance, we still need to double efforts to reduce inappropriate antibiotic use worldwide.

The current study adds to evidence from a February study published in the Journal of Environmental Chemical Engineering, which detailed how plastic waste, especially in freshwater environments, fosters the growth of antibiotic-resistant bacteria and resistance genes.

Plastics provide a surface for microbial colonization, forming what’s known as the “plastisphere.” The plastisphere can absorb antibiotics from the environment, creating a breeding ground for antibiotic-resistant bacteria and genes. 

“That’s a significant concern, not just in the U.S. but globally,” study author Hee Joo, director of Metropolitan State University of Denver’s environmental engineering program, said in a statement. “We already have microplastics detected in tap water, and water-treatment methods don’t remove them all,” she said. “Yet there is no regulation on microplastics in drinking water.”

“We hope that this paper can get more scientists, engineers, and more researchers to think about these questions,” Zaman said.

To reduce microplastic pollution, we need to make changes both individually and as a society, according to Savage. This means, he noted, using less plastic, choosing reusable items, and improving how we manage waste through better recycling and policies.