1. Institut Pasteur; Unité des Interactions Bactéries-Cellules; Paris F-75015 France
2. Inserm, U604; Paris F-75015 France
3. INRA, USC2020; Paris F-75015 France
4. Current address: CNRS, UMR 5236, CPBS; Montpellier F-34965 France
5. Laboratory of Microbial Biofilms, Instituto de Agrobiotecnología; Universidad Pública de Navarra-CSIC-Gobierno de Navarra; Campus de Arrosadía 31006 Pamplona Spain
6. Institut Pasteur, Plateforme de Microscopie Ultrastructurale; Imagopole Paris F-75015 France
7. The G.W. Hooper Foundation, Departments of Bioengineering and Therapeutic Sciences, of Microbiology and Immunology and of Pharmaceutical Chemistry; University of California, San Francisco; San Francisco CA 94143-0552 USA