Microplastics are now a major environmental pollutant with serious implications for public health. Researchers from Boston University have discovered that these tiny plastic particles play an active role in promoting antimicrobial resistance. Their study highlights how microplastics can increase the resistance of Escherichia coli to multiple antibiotics. This finding raises concerns about how microplastics may contribute to the rise of drug-resistant infections. This is especially worrisome in areas where plastic waste accumulates.
Microplastics and Antimicrobial Resistance: A Growing Concern
Understanding Microplastics and Antimicrobial Resistance
Experts describe microplastics as tiny plastic particles measuring less than five millimeters in size. They originate from various sources. These include single-use plastic containers, synthetic textiles like polyester, and industrial processes. These minuscule materials accumulate in natural environments like oceans, soil, and even the air. Moreover, due to their small size, they are easily ingested by marine organisms, animals, and humans.
Scientists have long studied the environmental impact of microplastics. Current research direction is focused on pollution and ecosystem destruction. Some undertakings are focused on their health implications. Furthermore, based on the findings of researchers from Boston University, which were published on 11 March 2025 in Environmental Microbiology, microplastics may contribute to the emergence of bacterial species with antimicrobial resistance.
It is estimated that there are 4.95 million deaths associated with antimicrobial-resistant infections each year. This is a serious public health issue. Bacteria become resistant to antibiotics for many different reasons. These include improved use and overprescribing of relevant medications. Another huge factor that fuels antimicrobial resistance is the microenvironment is the immediate surroundings of a microbe where it thrives and propagates.
Examining How Microplastics Contribute to Antimicrobial Resistance
Researchers conducted a controlled experiment using different microplastic types. These include polyethylene, polystyrene, and polypropylene. The microplastics are also categorized into three size ranges. They then incubated E. coli bacteria with these plastics for ten days and tested the resistance of these bacteria to four commonly used antibiotics. The goal was to observe how exposure to microplastics influenced antimicrobial resistance over time. The results of the experiment revealed key insights:
• Rapid Resistance Development: The tested E. coli developed multidrug resistance within five to ten days of exposure to microplastics.
• Biofilm Formation: Microplastics encouraged bacteria to form biofilms. This specifically made them more resistant to antibiotics.
• Persistent Resistance: Moreover, even after removing microplastics, bacteria retained their increased resistance, showing long-term effects.
• Plastic Type Influence: Polystyrene microplastics had the strongest impact on resistance compared to polyethylene and polypropylene.
• Environmental Implications: Wastewater, a primary source of microplastic pollution, may serve as a breeding ground for resistant bacteria.
Additional Explanations and Important Implications
Bacteria can attach to microplastics and form biofilms. These biofilms protect bacteria from external threats like antibiotics. In addition, unlike other surfaces, microplastics seem to enhance bacterial resistance due to their chemical composition and ability to absorb contaminants. The study found that the bacteria continued to show increased resistance even when microplastics were removed. This suggests that microplastics do more than just carry resistant bacteria. They actively promote conditions that strengthen antibiotic resistance.
The findings suggest that microplastics are not just passive pollutants. These materials actively drive antimicrobial resistance. This is especially concerning for regions with poor waste management. Refugee settlements and high-density urban areas face a higher risk because plastic waste accumulates rapidly.
Researchers N. Gross et al. are planning to investigate real-world environments to confirm their laboratory findings. They aim to look into refugee camps where plastic waste and bacterial infections are common. Understanding how different bacterial species adapt to microplastics in natural settings will help develop targeted interventions. Moreover, in the long term, reducing plastic pollution and improving waste management systems should be part of efforts aimed at mitigating or addressing the risk of antimicrobial resistance.
FURTHER READING AND REFERENCE
- Gross, N., Muhvich, J., Ching, C., Gomez, B., Horvath, E., Nahum, Y., and Zaman, M. H. 2025. “Effects of Microplastic Concentration, Composition, and Size on Escherichia coli Biofilm-Associated Antimicrobial Resistance. “In Applied and Environmental Microbiology. American Society for Microbiology. DOI: 1128/aem.02282-24