The Inserm team led by Guillaume Duménil at the Institut Pasteur, in collaboration with several teams of physicists, has unraveled a key stage in infection by Neisseria meningitidis, a human pathogen responsible for meningitis in infants and young adults. Bacterial aggregates in blood vessels appear to facilitate the progression of the disease. Even if treatment is administered rapidly, the mortality rate due to meningococcal infections remains very high.