Mapping the full evolutionary journey of a major generalist pathogen

Anna K. Pöntinen

Anna K. Pöntinen


Enterococcus faecalis represents a classical generalist micro-organism. We sequenced over 2,000 E. faecalis isolates, ranging from the pre-antibiotic era in 1936 up to 2018 and covering a large set of host species, by using Illumina HiSeq and a genetically representative subset with Oxford Nanopore long-read technology, allowing fully contiguous hybrid assemblies for 335 isolates. We identified multiple extant hospital-associated lineages, with the last common ancestors dating back as far as the 19th century, and found that the apparent hospital adaptations likely predate the modern hospital era, indicating selection in another niche, and underlining the generalist nature of this nosocomial pathogen.​


Anna K. Pöntinen received a DVM in 2013 and a Ph.D. in 2019 at the Faculty of Veterinary Medicine of the University of Helsinki, Finland. Her Ph.D. focused on the genetic determinants of environmental stress responses in food-borne pathogenic bacteria. In 2019, she was granted an ongoing 3-year Marie Sklodowska-Curie Fellowship at the Department of Medicine of the University of Oslo, Norway, in Prof Jukka Corander’s group. Her work focusses on bacterial population genomics, in particular bacterial evolution and host transmission, and global dissemination of antimicrobial resistance.