Minuscule particles of plastic are not only bad for the environment. A study led from Umeå University, Sweden, has shown that the so-called nanoplastics which enter the body can impair the effect of antibiotic treatment. The results also indicate that the nanoplastics may lead to the development of antibiotic resistance. Even the indoor air in our homes contains high levels of nanoplastics from, among other things, nylon, which is particularly problematic.
"The results are alarming considering how common nanoplastics are and because effective antibiotics for many can be the difference between life and death," says Lukas Kenner, professor at the Department of Molecular Biology at Umeå University and one of the researchers who led the study.
Nanoplastics are plastic particles that are smaller than a thousandth of a millimetre. Due to their smallness, they can float freely in the air and have the ability to enter the body.
In the study, led not only by researchers in Umeå, but also by scientists based in Germany and Hungary, the authors have focused on how some of the most common nanoplastics interact with tetracycline, which is a common broad-spectrum antibiotic. It turned out that there was significant accumulation of the antibiotics on the surfaces of the nanoplastic particles. You could say that the nanoplastics absorb antibiotics.
The nanoplastics in question come from common types of plastics such as polyethylene, polypropylene, polystyrene and nylon. They are commonly found in packaging and textiles. Indoor air contains about five times as much nanoplastics as outdoor air, partly due to particles released from textiles.
One risk that the researchers point out is that the binding to nanoplastics can lead to the antibiotics "hitchhiking" with the nanoplastic in the bloodstream and being transported to other places in the body than they are intended for. This can both reduce the targeted effect of the antibiotics and risk enabling the emergence of antibiotic-resistant bacteria. When antibiotics accumulate in unintended areas, sub-lethal doses can spur bacterial mutations, selecting for antibiotic-resistant strains.
The researchers used advanced computer models to analyze how the nanoplastics bind to tetracycline. It turned out that the bond was particularly strong to nylon – one of the substances that is most abundant in nanoplastics in indoor air.
"Although more research is needed to shed light on the connections and possible measures, we can conclude from our results that nanoplastics are a health risk that should be taken more seriously," says Lukas Kenner.
The study, which is published in the scientific journal Scientific Reports, has been led by Lukas Kenner at Umeå University, Barbara Kirchner at the University of Bonn in Germany and Oldamur Hollóczki at the University of Debrecen, Hungary. The sub-study on the binding of nanoplastics to antibiotics has been led by Nikola Zlatkov Kolev at the Department of Molecular Biology at Umeå University. Lukas Kenner has recently taken up the position of visiting professor at the Department of Molecular Biology at Umeå University and continues his research on nanoplastics and health effects.