Nanoplastics can reduce effectiveness of antibiotics

An international team of researchers has investigated how nanoplastic particles deposited in the body affect the effectiveness of antibiotics, finding that the plastic particles not only impair the effect of the drugs but could also promote the development of antibiotic-resistant bacteria. The results of their study have been published in the journal Scientific Reports.

Nanoplastics are smaller than 0.001 mm and are considered particularly harmful to humans and the environment due to their small size. In order to investigate whether and how nanoplastic particles in the body interact with antibiotics, the research team led by Lukas Kenner (Medical University of Vienna), Barbara Kirchner (University of Bonn) and Oldamur Hollóczki (University of Debrecen) linked a common drug with widely used types of plastic.

The team’s focus was on the broad-spectrum antibiotic tetracycline, which is used to treat many bacterial infections, such as those of the respiratory tract, skin or intestines. When it came to plastics, the choice fell on polyethylene, polypropylene and polystyrene, which are ubiquitous components of packaging materials, as well as nylon 6,6, which is contained in textiles such as clothing, carpets, sofa covers and curtains.

Using complex computer models, the team was able to prove that the nanoplastic particles can bind tetracycline and thus impair the effectiveness of the antibiotic. Kenner noted that this binding was “particularly strong with nylon”, while pointing out a largely underestimated danger indoors.

“The micro- and nanoplastic load is around five times higher there than outdoors,” he said. “Nylon is one of the reasons for this: it is released from textiles and enters the body via respiration, for example.”

As the study results show, the binding of tetracycline to nanoplastic particles can reduce the biological activity of the antibiotic. At the same time, binding to nanoplastics could lead to the antibiotic being transported to unintended sites in the body, causing it to lose its targeted effect and possibly causing other undesirable effects.

“Our finding that the local concentration of antibiotics on the surface of the nanoplastic particles can increase is particularly worrying,” Kenner said. This increase in concentration could lead to the development of antibiotic-resistant bacteria, with plastics such as nylon 6,6 as well as polystyrene, which bind more strongly to tetracycline, of particular concern.

The study thus shows that exposure to nanoplastics is not only a direct health risk, it can also indirectly influence the treatment of diseases. In the future, Kenner hopes to conduct further studies looking at the influence of nanoplastics on other drugs.

Image credit: iStock.com/Svetlozar Hristov