Microplastics Could Be Creating Dangerous Antibiotic-Resistant Bacteria

Microplastics Could Be Turning Bacteria into Drug-Resistant Superbugs

By Marta Zaraska edited by Lauren J. Young

For bacteria, microplastics are the perfect meetup spot—tiny, intimate surfaces where microbes can cling, huddle close and swap genes. And these crowded bacterial breeding grounds may pose a threat to human health. A growing body of new research shows that microplastics may fuel antimicrobial resistance—the phenomenon in which pathogens adapt to withstand drugs, making it challenging to treat infections. The growing antimicrobial resistance crisis claimed about five million lives in 2019, a number projected to double by 2050. In an August research review, scientists called attention to the “silent tsunami” of plastics-driven antibiotic resistance. Several other recent papers suggest microplastics serve as better homes for pathogens than some natural substances do, although the mechanisms are not fully understood.

“We’ve just really scratched the surface,” says Timothy Walsh, a microbiologist at the University of Oxford, who has previously studied antimicrobial resistance and microplastics.

When bacteria encounter a surface—a sliver of wood floating in water or a door handle—they stick to it and to one another, forming a biofilm. As they attach, “they grow and proliferate,” says Muhammad Zaman, a biomedical engineer at Boston University. In a biofilm, bacteria live close together, making it easier to transfer genetic material from one cell to another in what’s “basically bacterial sex,” says Emily Stevenson, a public health researcher at the University of Exeter in England and lead author of the August review paper. The more chances microbes get to swap genes in general, the more chances they have to spread DNA that codes for antibiotic resistance.

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Scientists in Germany, Costa Rica and the U.K. first detected the troubling trend in 2018, when they showed that bacteria on microplastics were more inclined than free-living bacteria to exchange genes encoding resistance to…