Microplastics may be more than environmental pollutants—they could contribute to the rise of drug-resistant bacteria. These tiny plastic fragments persist in wastewater, providing surfaces where bacteria congregate, form biofilms, and exchange genetic material that enhances antibiotic resistance. A recent study found that Escherichia coli cultured on microplastics were 171 times more resistant to the antibiotic ciprofloxacin than those grown on glass.

Researchers exposed E. coli to different types of microplastics—polyethylene, polystyrene, and polypropylene—at varying concentrations and sizes. They measured the bacteria’s survival rates and assessed whether they developed resistance to four common antibiotics: ampicillin, ciprofloxacin, doxycycline, and streptomycin. They also compared bacterial behavior on microplastics versus glass to determine how different surfaces influenced biofilm formation.

Bacteria attached to microplastics formed stronger biofilms and exhibited higher antibiotic resistance than those grown on glass. The water-repellant nature of the plastics, combined with their ability to attract and retain other substances, likely contributed to this effect. Bacteria grown in the presence of antibiotics and microplastics showed considerably greater resistance, with those exposed to ciprofloxacin displaying up to 171 times greater resistance and other antibiotics showing increases of up to 75 times.

These findings suggest that microplastics serve as breeding grounds for antibiotic resistance, potentially increasing the risk of persistent infections in environmental and healthcare settings. Addressing microplastic pollution may be crucial in slowing the spread of drug-resistant bacteria. Learn how to limit your exposure to microplastics in this episode featuring Dr. Rhonda Patrick.