Research theme: Microbial pathogenesis
My main research interest is staphyloccocal pathogenesis and in particular the study of the surface components implicated in the infection. Pathogenicity in Staphylococcus aureus is based on a wide range of cell wall-associated adhesins and extracellular toxins.
These microorganisms are particularly well equipped with surface adhesins or MSCRAMMs - for Microbial Surface Components Recognizing with Adhesives Matrix Molecules - which are able to bind to the host extracellular matrix. Based on S. aureus genome sequences, 21 genes encoding this type of surface proteins bear the LPXTG motif, which is known to be responsible for the covalent anchoring of these proteins to the cell-wall peptidoglycan.
The original approach developed in our laboratory has shown that the transfer of individual virulence determinants from S. aureus into the less pathogenic bacterium Lactococcus lactis has clearly identified clfA and fnbA genes as critical virulence factors of S. aureus.
The remaining 19 proteins are not directly and significatively implicated in invasive and persistent infection whereas they are able to bind components of extracellular matrix (notably fibrinogen and fibronectin). We are interested in understanding how these proteins are implicated in infection and especially their presence in the genome.
To resolve this question, proteome analysis of the microbial surface of different staphyloccocal strains, in different conditions and growth phase, is at present under investigation, also in vivo, experiments are being carried out. Indeed, a better understanding of the nature and the presence of this virulence factors at the infection site are essential to develop new drugs and therapies against staphyloccocal infections, for example molecules able to block or to inhibit MSCRAMMs implicated in the pathogenicity.
Beside this main subject, I'm also partly implicated in the understanding of interactions between Caenorhabditis elegans and bacteria. C. elegans is a bacteria-feeding nematode increasingly used for the screening of microbial pathogenic factors. Most natural environments offer a variety of food sources to animals that inhabit them and therefore, feeding usually involves making choices between foods. We are testing whether food-choice could be used as a rapid method to detect toxic products.
Since October 2006
Study of S. aureus pathogenicity - Fundamental Microbiology Department, Philippe Moreillon's group (Lausanne, Switzerland)
September 2005 to July 2006
Study of the pathogenicity of S. aureus in the host-model C. elegans. Laboratory of bacteriology, INSERM E-0230, François Vandenesch and Jérôme Etienne's group (Lyon, France)
January 2005 - July 2005
Research of mutants in C. elegans to develop new drugs for the treatment of the Duchenne muscular dystrophy and genetic screen by RNAi on muscular dystrophic mutants. Molecular and Cellular Genetic Center, Laurent Ségalat's group (Lyon, France)
Since October 2006
PhD in the Fundamental Microbiology Department - Lausanne, Switzerland
2004 - 2006
Master of Molecular and Cellular Biology, and Oncology - Lyon, France
2001 - 2004
Bachelor of Cellular Biology and Physiology - Genetic, Lyon
1999 - 2001
First year in Medical School - Faculté de Médecine Lyon-Nord, UCBL, Lyon
Since July 2007
Scientific moderator : Discovery activities of sciences "un monde invisible autour de nous" and "les bactéries au service de l'homme" at the Eprouvette (Interface science-society, Lausanne, Switzerland)
Experimentation animal courses (module 1) - Centre Hopitalier Universitaire Vaudois (Lausanne, Switzerland)
Ythier M, Entenza JM, Bille J, Vandenesch F, Bes M, Moreillon P, Sakwinska O. Natural variability of in vitro adherence to fibrinogen and fibronectin does not correlate with in vivo infectivity of Staphylococcus aureus. Infection and Immunity 2010.
Haenni M, Galofaro L, Ythier M, Giddey M, Majcherczyk P, Moreillon P, Madec JY. Penicillin-Binding Protein Gene Alterations in Streptococcus uberis Isolates Presenting Decreased Susceptibility to Penicillin. Antimicrobial Agents and Chemotherapy 2010 ; 54(3):1140-5.