Population genetics and epidemiology of human commensals

We investigate microbial populations and the molecular epidemiology of human-associated bacteria, including pathogens and commensals. These studies are the basis for defining evolutionary lineages and sub-populations within a given species. The analyses include sequencing of single genes as well as whole bacterial genomes and comparative sequence analyses. The aim is to detect genetic differences among sub-populations, correlate these differences to clinical manifestations and identify underlying factors responsible for the differences in disease outcome and health associations, respectively. The genetic mechanisms causing the variation and the evolution and spread of the bacterial species are studied and applied to collections of bacteria isolated over time from different geographical areas and from well-defined infections and/or bacteria isolated from healthy carriers.

Figure: Comparison of the tetanus toxin-encoding plasmid of diverse strains of Clostridium tetani