Microplastics May Contribute to Antibiotic Resistance

Microplastics — defined as plastic particles under 0.2 inches – have been discovered most recently in human lungs and brains, as well as in our livers, kidneys, and testes. They have so far been associated with some cancers, respiratory diseases, and pregnancy and birth complications.

Now researchers are adding another ill effect to the persistent particles — boosting antibiotic resistance, according to a study recently published in the journal Applied and Environmental Microbiology.

Laboratory experiments conducted by a team of Boston University researchers demonstrated that bacteria exposed to microplastics became resistant to multiple types of antibiotics. Antibiotic resistance — most often associated with over-prescription and unnecessary use of antibiotics — has been a public health concern for decades.

Adding another means that could make these drugs less effective is concerning, according to the authors — especially for people in dense, impoverished areas, where discarded plastic often accumulates.

“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,” Muhammad Zaman, a Boston University College of Engineering professor and co-author of the paper, said in a press release. “There is certainly a concern that this could present a higher risk in communities that are disadvantaged.”

Read More: Our Brains Are Soaking Up Microplastics More Than Other Organs

The authors experimented with multiple kinds of plastics as well as a variety of antibiotics. Each time they came up with the same results: bugs that survived. When bacteria attach to a surface they create a biofilm — a sticky substance that acts as a protective shield.

Although bacteria can grow this film on any surface, the authors say that the effect was “supercharged” on microplastics. They found the rate of antibiotic resistance so high on microplastics versus other materials that they repeated their experiments multiple times. The results remained the same.

“We’re demonstrating that the presence of plastics is doing a whole lot more than just providing a surface for the bacteria to stick — they are actually leading to the development of resistant organisms,” Zaman said.

Read More: Microplastics Are Everywhere. What Are They Doing to Our Health?

According to the United Nations Environmental Program, research on over 13,000 chemicals used in plastic manufacturing has shown that at least 3,200 may be hazardous to human health.

Although scientists keep finding microplastics in more places and associating them with a longer list of potentially bad health effects, so far most of the research has been in the laboratory. For instance, another study has shown that microplastics can damage human cells.

The next step — whether scientists are looking at their impact from diseases ranging from cancer to infections — will be to study exactly how microplastics directly affect human health.

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• Applied and Environmental Microbiology. Effects of microplastic concentration, composition, and size on Escherichia coli biofilm-associated antimicrobial resistance

• United Nations Environmental Program. Chemicals in Plastics - A Technical Report

• The Guardian. Microplastics cause damage to human cells, study shows

Before joining Discover Magazine, Paul Smaglik spent over 20 years as a science journalist, specializing in U.S. life science policy and global scientific career issues. He began his career in newspapers, but switched to scientific magazines. His work has appeared in publications including Science News, Science, Nature, and Scientific American.