Séminaire CIRI: François LEBRETON
Date / Heure
Date(s) - 20/12/2017
0 h 00 min - 12 h 00 min
salle des Thèses Chantal Rabourdin-Combes
François LEBRETON (Massachusetts Eye and Ear infirmary, Boston– USA): «Tracing the Evolution of Bacterial Pathogens, from Paleozoic Origins to the Hospital»
Why, among the vast diversity of gut flora, enterococci are so well adapted to the modern hospital environment. Molecular clock estimation, together with analysis of their environmental distribution, phenotypic diversity and concordance with host fossil records, place the origins of the enterococci around the time of animal terrestrialization – 425 – 500 MYA. Speciation appears to parallel the diversification of hosts, including the rapid emergence of new enterococcal species following the End Permian Extinction. Major drivers of speciation include changing carbohydrate availability in the host gut. Life on land would have selected for the precise traits that now allow pathogenic enterococci to survive desiccation, starvation, disinfection and antibiotic treatments in the modern hospital; foreordaining the emergence of MDR lineages as leading hospital pathogens.