Nanoplastics can make E. coli infections worse: study Premium

New research shows nanoplastics increase pathogen risk, affecting E. coli virulence and gene transfer, posing health hazards.

Nanoplastics are bad news even though each one is only as small as a smoke particle. Research has shown that micro- and nano-plastics are present at the top of the tallest mountains, at the bottom of the deepest trenches, and even in our bloodstream, tissues, and in newborns as well. Their build-up has many toxic effects, including damage to cells and the genetic material inside.

Now, a new study from researchers at the University of Illinois, Urbana-Champaign, has revealed that nanoplastics aren’t just risky on their own: they also increase the risk from pathogens. The researchers found that nanoplastics with positively charged surfaces could make Escherichia coli, a foodborne pathogen, more virulent.

The findings were published in the Journal of Nanobiotechnology.

E. coli bacteria have a negative charge on their outer membranes. This can attract positively charged nanoplastics and increase the stress on the bacterium, making it produce more Shiga-like toxins. These are the proteins E. coli secrete and which cause disease.

In older studies, scientists have looked at the impact of charged surfaces on non-pathogenic bacteria. The new study examined how charged surfaces affected a particular strain of E. coli. Similarly, while previous studies focused primarily on free-floating cells, the new one studied both free-floating cells and biofilms — a community of bacteria sticking to each other over a surface. Biofilms are hotspots where bacteria exchange genetic material with their neighbours. 

The team members used a pathogenic E. coli strain that was resistant to the antibiotic rifampicin. They cultured the strain on agar plates and a nutrient-rich liquid medium called LB broth. Then they exposed the bacteria to polystyrene-based nanoplastics with three kinds of charges: positive, negative, and neutral.

The team also cultured a second set of E. coli cells in LB broth for use as a control. This group wasn’t exposed to nanoparticles.