Plastic pollution in the ocean could serve as a source of new antibiotics, according to a new study led by students in collaboration with the Scripps Institution of Oceanography. The research will be presented at the American Society for Microbiology conference in Washington, DC, June 9-13, 2022.

Scientists estimate that between 5 and 13 million metric tons of plastic pollution enter the oceans each year, ranging from large floating debris to microplastics on which microbes can form entire ecosystems. Plastic debris is rich in biomass and therefore could be a good candidate for the production of antibiotics, which tends to occur in highly competitive natural environments.

To explore the potential of the plastisphere as a source of new antibiotics, researchers modified the Tiny Earth citizen science approach (developed by Dr. Jo Handelsman) to marine conditions. The researchers incubated high- and low-density polyethylene plastic (the type commonly seen in grocery bags) in water near Scripps Pier in La Jolla, California, for 90 days.

The researchers isolated 5 antibiotic-producing bacteria from ocean plastic, including strains of Bacillus, Phaeobacter and Vibrio. They tested the bacterial isolates against a variety of Gram positive and negative targets, finding the isolates to be effective against commonly used bacteria as well as 2 antibiotic resistant strains.

“Given the current antibiotic crisis and the rise of superbugs, it is essential to seek alternative sources of new antibiotics,” said study lead author Andrea Price of National University. “We hope to expand this project and further characterize the microbes and the antibiotics they produce.”

This project was part of a STEM education project funded by the National Science Foundation.