Dr Lucy Weinert

Host switches

Some of our most serious pandemics are caused by pathogens switching and establishing in a new host species. We use bacterial genomes, molecular dating and information about host species to examine how bacteria adapt to the new host and the ecological context for switching. For example, we showed that farming practices (Weinert et al. 2012; Weinert et al. 2015a; Murray et al. 2023), antibiotic use (Matuszewska et al. 2022; Dresen et al. 2025), host relatedness (Waxman et al. 2014) and host immunity (Weinert et al. 2015b) are predictors of host switch and/or establishment success.

Antimicrobial resistance and vaccine development

Antimicrobial resistance threatens the effective treatment of bacterial infections and makes routine medical procedures less safe. We investigate the genetic basis of antimicrobial resistance (Hadjirin et al. 2021) and look how these genetic variants evolve in a range of different bacteria (Matuszewska et al. 2022; Dresen et al. 2025). We also use bacterial genomics to create new vaccines with the goal of reducing antimicrobial usage.

Genome reduction and pathogenicity

We are currently studying the link between reductive genome evolution and pathogenicity. Bacterial pathogens very often have smaller genomes and fewer genes than their nearest non-pathogenic relatives. However, despite much speculation, it remains unclear why this pattern holds. We are addressing this phenomenon using Streptococcus suis, a bacterium that is common in non-pathogenic forms, but which also causes serious diseases in pigs and humans (Weinert et al. 2015a). We sample whole genomes of global S. suis populations and use bioinformatic and laboratory approaches to test hypotheses about gene loss and pathogenicity.