Philippe Glaser, research director at the Institute Pasteur, is heading the Ecology and Evolution of Antibiotic Resistance Unit. He is an internationally recognized expert in bacterial genomics and evolution. He is well known for his genomic-epidemiology studies of Group B Streptococcus (GBS) both in human and in animals. He has shown how the extensive use of tetracycline starting in the 1950s has been responsible for the replacement of the GBS population colonizing humans by few tetracycline resistance clones and to the emergence of neonatal GBS infection in the 1960s – 1970s both in Europe and in the US. With his group, he has developed a general framework for evolutionary analyses of disseminating lineages that he applied to a bovine GBS clone endemic in Portugal and to the hypervirulent ST17 lineage. In collaboration with Thierry Naas at the Bicêtre Hospital he is currently deciphering the genetic bases for the emergence and dissemination of carbapenemase producing Escherichia coli and Klebsiella pneumoniae lineages. He is directing the « Fighting Antibiotic Resistance » program aiming to federate research on antibiotics and antibiotic resistance at the Institut Pasteur (IP) and in the Institut Pasteur International Network.