Invisible fragments of plastic are infiltrating our environment—and possibly turning everyday bacteria into more dangerous threats. New research suggests that nanoplastics could be making E. coli O157:H7, a notorious foodborne pathogen, even more virulent by triggering stress responses that ramp up toxin production. Could your takeout container be indirectly weaponizing your next meal?
Key Points at a Glance
- Positively charged nanoplastics were found to increase the virulence of E. coli O157:H7.
- These plastics induced stress in bacteria, leading to increased production of Shiga-like toxin.
- The effect persisted even in resilient bacterial biofilms, not just in free-floating cells.
- Study highlights how tiny plastics could affect public health by altering bacterial behavior.
- Further research will explore links between nanoplastics, antibiotic resistance, and food safety.
Nanoplastics are the invisible invaders of our age—fragmented from larger plastics, too tiny to see, yet nearly impossible to avoid. They’re in oceans, drinking water, soil, and increasingly, in our bodies. Now, a groundbreaking study from the University of Illinois Urbana-Champaign raises an even more unsettling possibility: these tiny plastic shards may be making foodborne pathogens more dangerous.
Led by Associate Professor Pratik Banerjee and his team from the Department of Food Science and Human Nutrition, the study is the first of its kind to explore how nanoplastics affect the behavior of human pathogenic bacteria. The focus was E. coli O157:H7, a familiar name in food safety circles thanks to its association with outbreaks traced to undercooked meat, unwashed produce, and contaminated water.
Banerjee’s team zeroed in on surface charge—the electrical characteristics of nanoplastics. They produced particles from polystyrene, the same material used in takeout containers, and chemically altered them to carry positive, negative, or neutral charges. When introduced to E. coli, the results were telling.
Bacteria carry a naturally negative surface charge, and as the team hypothesized, they were most reactive to the positively charged nanoplastics. These particles clung to E. coli and induced physiological stress. But the surprise came in how the bacteria responded: they didn’t just survive—they lashed out. Specifically, they produced higher levels of Shiga-like toxin, the main agent of illness in infected humans.
The effects of the nanoplastics weren’t limited to one form of bacterial life. In both free-floating E. coli and in biofilms—complex bacterial communities known for their resistance to antibiotics and sanitizers—the positively charged plastics triggered similar stress responses. Although bacterial growth initially slowed, the cells adapted and rebounded. The danger remained: more stress meant more toxins.
Biofilms represent a critical challenge in healthcare and food safety. Found on everything from catheters to industrial food equipment, they provide bacteria with a protective matrix that helps them resist chemical attack. When E. coli forms biofilms on microplastics, it may gain both protection and new exposure to virulence-enhancing nanoplastics. This combination, the study suggests, could create hidden hotspots for bacterial evolution and pathogenicity.
This is no longer a purely academic concern. Previous studies have shown that microplastic-associated biofilms may facilitate the exchange of antibiotic resistance genes—a bacterial arms race playing out on a microscopic level. Banerjee’s group plans to explore how this process unfolds when bacteria meet nanoplastics in real-world environments, including food production systems and agricultural soils.
Although the immediate findings don’t signal a public health crisis, they raise important questions about the broader implications of plastic pollution. Plastics were once hailed as revolutionary materials. But their afterlife—as micro- and nanoplastics—is writing a new chapter in environmental science, one where unintended interactions between human waste and microbial life can have unpredictable and potentially harmful outcomes.
The researchers’ next steps will focus on understanding how different types of plastic and associated chemical residues affect pathogenic bacteria. They also aim to examine the potential for increased transmission, changes in resistance profiles, and the stability of these behaviors across bacterial generations.
As Banerjee explains, this research marks the beginning of a complex journey into the world of microbe-plastic interactions. “Plastics have an enormous ability to adsorb chemicals,” he notes. “This is the first step in understanding how their surface characteristics might change the behavior of pathogens that affect human health.”
It’s a sobering reminder that even the tiniest bits of our waste can have outsized effects—not just on the planet, but on the organisms we share it with, and ultimately, on ourselves.
Source: University of Illinois College of Agricultural, Consumer and Environmental Sciences
