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