Microplastics don't just pollute our oceans. They could also accelerate bacterial resistance to antibiotics, according to a recent study.
Researchers discovered that microplastics promote the development of antibiotic resistance in
E. coli, even in the absence of medication. This study, published in
Applied and Environmental Microbiology, shows that plastic particles act as catalysts for antimicrobial resistance.
The team tested several types of plastic, including polystyrene and polyethylene, to assess their impact on
E. coli. The results indicate a rapid increase in resistance to four major antibiotics in just a few days. This resistance persists even after the removal of microplastics.
The implications of these findings are far-reaching, highlighting the urgent need to reduce plastic pollution. Microplastic-induced resistance could render essential antibiotic treatments ineffective.
How do microplastics influence antibiotic resistance?
Microplastics serve as a substrate for bacteria, creating an environment conducive to the exchange of resistance genes. This phenomenon, known as horizontal gene transfer, is facilitated by the proximity of bacteria on plastic surfaces.
The formation of biofilms on microplastics protects bacteria from environmental stresses, including antibiotics. These biofilms act as both a physical and chemical barrier, reducing treatment effectiveness.
Microplastics can also absorb organic pollutants, creating conditions that favor the selection of resistant bacteria. This interaction between plastics and pollutants amplifies the risk of antimicrobial resistance.
Why does resistance persist after microplastic removal?
The resistance acquired by bacteria can be encoded in their DNA, becoming a stable characteristic of their genome. This genetic modification allows bacteria to maintain their resistance even in the absence of the initial selective pressure.
Bacteria can also transfer these resistance genes to other bacteria, including those not exposed to microplastics. This genetic sharing mechanism accelerates the spread of resistance in bacterial populations.
Finally, stressful environmental conditions, such as the presence of microplastics, can activate DNA repair and mutation mechanisms in bacteria. These mutations may include resistance traits that persist long-term.