During her thesis at the Institute for Structural Biology (IBS) in the group of Thierry Vernet, Cécile developed a fluorescent labelling method to localize, using optical microscopy, proteins in charge of cell division in an important human pathogen: Streptococcus pneumoniae (the pneumococcus). For the first time, these large protein assemblies were visible in the cell at a resolution of a few hundred nanometers. In parallel, she solved the crystallographic structure of one component of these complexes to constrain the model proposed for S. pneumoniae division.

Following her Ph.D. (2003), she completes her training in crystallography as a postdoctoral fellow in the group of Stephen Cusack (EMBL, Grenoble). Next, she enlarges her competences in microbiology during a second postdoctoral internship in the group of David Rudner (Harvard Medical School, Boston), during which she studies two protein complexes involved in spore development in Bacillus subtilis.

She is recruited by the CNRS in 2010 and joins the Pneumococcus group at the IBS to continue her research activities on bacterial morphogenesis and division, using complementary techniques in structural and cellular biology. Her recruitment coincides with the emergence of super-resolution fluorescence microscopy techniques, which allow connecting protein and cellular scales. She decides to develop the use of these techniques in the pneumococcus in collaboration with biophysicists from the IBS (Dominique Bourgeois and Virgile Adam, Pixel team) and a chemist from the University Grenoble Alpes (Yung-Sing Wong, Department of Molecular Pharmacochemistry). The developed methods, based on the localization of single molecules and on "click chemistry", now allow her to image the assembly and activity of protein machineries in charge of cell division at a resolution of about ten nanometers. Because it reveals molecular details that are inaccessible at low resolution, her work in structural biology and cell imaging helps understanding how bacteria acquire their shape and proliferate. This fundamental knowledge is pertinent for the discovery of new antibiotics and for the comprehension of associated resistance mechanisms.