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The link between antibacterial biocide pollution and antibiotic resistance


Many antibacterial biocides that risk boosting the emergence and spread of antibiotic resistance end up in the sea, lakes, and watercourses. In the BIOCIDE research project, which is led by the University of Gothenburg, researchers will develop methods for assessing and managing these risks.

Joakim Larsson
Photo: Johan Wingborg

Joakim Larsson, Professor of Environmental Pharmacology and director of CARe, the Centre for Antibiotic Resistance Research at the University of Gothenburg, is heading this international project. BIOCIDE will run until 2024, and has just received just over SEK 1.7 million Euro in funding from, among others, the Swedish Research Council and Formas (the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning).

Taking part in the project are research groups from another five European countries: Denmark, Norway, Romania, the Czech Republic, and Germany, whose research councils are also contributing funds for this joint initiative.

Antibacterial biocides are used in an ever increasing number of products and processes in society. Examples are surface treatment for various consumer goods, hygiene products, agriculture, and industrial manufacturing processes.

This huge range of uses entails a risk of antibacterials boosting the development of antibiotic resistance, since some of these substances confer competitive advantages for bacteria that have become resistan

Two phenomena underlying rise of resistance

“Bacteria often defend themselves in exactly the same way against various antibacterial substances as against antibiotics, which are vitally important for us. When, the bacteria become resistant to biocides, they thereby become more difficult to treat with antibiotics when we’re infected by them — a phenomenon known as cross-resistance,” Larsson explains.

Another mechanism is when different genes are involved in making the bacteria resistant to antibacterial substances and antibiotics, respectively. This is known as co-selection.

“Genes for both of these properties are often contained in the same plasmids — that is, mobile, circular DNA molecules that can be transferred between different bacteria. Antibiotic-resistant bacteria that carry plasmids of this kind are favored by the presence of biocides,” Larsson explains.

Different biocides, different risks

In marine environments worldwide, there is large-scale direct exposure to substances with antibacterial properties contained in marine paints, such as copper and zinc.

“Effective marine paints are often crucial to reduce fouling on the hulls, which causes drag and thereby boosts vessels’ fuel consumption. In this project, we’re setting out to investigate the extent to which boat and ship hulls might also be hotbeds for resistant bacteria and effective transporters of these bacteria between countries,” Larsson relates.

However, not all antibacterial agents represent the same risks. As luck would have it, regular alcohol-based hand sanitizer, for example, seems to make no contribution whatsoever to antibiotic resistance.

In healthcare, antibacterial agents are often indispensable as disinfectants. But in society at large, where infection risk is often minimal, the wide-ranging use of antibacterial biocides is highly questionable, Larsson thinks.

Classified as major challenge to society

The BIOCIDE project is part of the EU Joint Programming Initiatives (JPIs), in which EU member states voluntarily agree on common visions and strategic research agendas to tackle major challenges to society. BIOCIDE has been selected for inclusion within the scope of a joint call for research proposals from the three initiatives JPI-AMR (antimicrobial resistance), JPI-OCEANS, and JPI-WATER. The funding comes from the respective countries involved.


Joakim Larsson’s research group

Centre for Antibiotic Resistance Research at the University of Gothenburg (CARe)