19.09.2026
Lindsay Sonnenkalb receives Isabelle-Olivieri Medal
Dr. Lindsay Sonnenkalb from the Research Center Borstel, Leibniz Lung Center (FZB) has been awarded the 2026 Isabelle-Olivieri Medal for an outstanding publication in the field of translational evolutionary research. The €5,000 award was presented early September during the TransEvo retreat “Evolution by the Lake”.
The award recognises the paper ‘The mutant selection window of moxifloxacin and bedaquiline-resistant Mycobacterium tuberculosis’, which was published in 2025 in the Journal of Infection . As part of this study, Lindsay Sonnenkalb and her colleagues investigated the conditions under which resistance to the key tuberculosis drugs moxifloxacin and bedaquiline can develop.
Alexander Fleming already warned that exposing bacteria to insufficient concentrations of antibiotics could allow resistant bacteria to survive and multiply. This problem is particularly relevant for Mycobacterium tuberculosis, the bacterium that causes tuberculosis (TB). It can persist in different parts of the body and even inside cells, where antibiotics may not always reach the intended concentrations.
The study therefore investigated the “mutant selection window” – the range of drug concentrations in which resistant bacteria can survive while susceptible bacteria are eliminated. For moxifloxacin and bedaquiline, the researchers found that resistance could emerge at much lower drug concentrations than previously assumed – in some cases at only 6–12% of the concentration normally considered necessary to kill the bacteria.
The researchers also examined the “fitness cost” of resistance – in other words, whether becoming resistant makes the bacteria less competitive. Common moxifloxacin resistance mutations carried almost no fitness cost, meaning that resistant bacteria were able to grow almost as well as non-resistant bacteria. In contrast, mutations directly affecting bedaquiline’s target were associated with substantial fitness costs and reduced bacterial competitiveness.
The findings provide important insights into when resistant tuberculosis bacteria can emerge and persist. They also demonstrate how combining experimental research with mathematical modelling can help optimize antibiotic dosing and treatment strategies, with the aim of preserving the effectiveness of essential drugs and limiting the emergence of resistance.
About TransEvo
TransEvo ist ein von der Deutschen Forschungsgemeinschaft (DFG) gefördertes Graduiertenkolleg (GRK 2501) mit dem vollständigen Namen „Translationale Evolutionsforschung“ (Translational Evolutionary Research). Es wird von der Christian-Albrechts-Universität zu Kiel koordiniert und gemeinsam mit dem FZB und weiteren Forschungsinstituten in Schleswig-Holstein durchgeführt. Hier untersuchen Forschungsgruppen interdisziplinär wie Erkenntnisse der Evolutionsbiologie auf aktuelle gesellschaftliche Probleme angewendet werden können.