Group leader : Cécile Morlot

The pneumococcus

The pneumococcus is an ovoid Gram-positive commensal bacterium of the naso-pharyngeal flora of about 10% of the human population. When the pneumococcus invades other sites and tissues, it causes a variety of infectious diseases such as otitis, pneumonia, bacteremia and meningitis, killing over 1 million people per year worldwide.


The cell wall of the pneumococcus is constituted mostly of peptidoglycan, teichoic acids and proteins. The peptidoglycan is a mesh-polymer constituted of chains of disaccharide cross-linked by short peptides. The peptidoglycan is essential as it confers mechanical resistance and shape to bacteria. Teichoic acids are complex linear polysaccharides attached to the membrane or the peptidoglycan. Teichoic acids play important roles in the interactions with the environment and the regulation of cell wall metabolism.

To tackle fundamental questions pertaining to the cell surface biology of S. pneumoniae, the Pneumococcus Group applies a wide range of techniques with a strong focus on advanced optical and electronic microscopy, biochemistry and structural biology.

In parallel, we are interested in the sporulation of Bacillus subtilis.


Bacillus subtilis, bacterial cell wall, bacterial division, bacterial morphogenesis, beta-lactams, murein, penicillin-binding proteins (PBPs), peptidoglycan, peptidoglycan hydrolases, pneumococcus, sporulation, Streptococcus pneumoniae, teichoic acids.