A man standing in front of a lake. Photo. — “My research investigates mainly the environmental factor of One Health", says Paul Löffler. Photo: Ulrika Jansson Klintberg

How breakdown products from antibiotics and antivirals impact rivers and lakes

Page reviewed: 11/11/2025

Our results show that some antibiotic transformation products might retain antibacterial activity , which could be of interest to other sectors within One Health, especially considering the issue of antimicrobial resistance, says Paul Löffler, Department of Aquatic Sciences and Assessment.

Who are you? Could you give a short presentation of yourself and your research area?

“Hej, I am Paul. Over the past four years, I have conducted my PhD research under the guidance of my amazing main supervisor Foon Yin Lai in the department of Aquatic Sciences & Assessment. My research, summarized in my PhD thesis called “Impact of antimicrobial transformation products on aquatic environments” investigated the types of breakdown products and metabolites, collectively referred to as transformation products, of antibiotic and antiviral chemicals reach environmental waters such as rivers or lakes, and how to assess their risks to aquatic species. As antibiotics and antiviral medications are designed to have specific effects on bacteria we were also interested if the transformation products can retain some of the antimicrobial properties that the parent chemical has, and we investigated this computationally and with experiments in the lab.”

A man on a stage. Photo. — Paul Löffler presents his research at the conference EkoToxicoMic2024 in Gothenburg. Photo: Alina Koch

How does your research align with One Health?

“My research investigates mainly the environmental factor of One Health, as we conducted several studies with an environmental focus. However, our results that some antibiotic transformation products might also retain antibacterial activity could be of interest to other sectors within One Health, especially considering the issue of antimicrobial resistance.”

What are your plans after your PhD?

“After completing my PhD, I plan to take some time to relax, finalize ongoing projects, and travel. I really enjoy living in Sweden, but the winters can be tough, so I am planning to spend at least part of this coming winter in warmer climates.”

The public defence of Paul Löffler's thesis is on the 21 November. Read more on the calendar event page: Impact of antimicrobial transformation products on aquatic environments | slu.se