Abstract
Before the era of antibiotics, bacterial infections had serious health consequences, and certain epidemic episodes could prove dramatic. Over the course of the 20th century, the discovery of these molecules has considerably changed the way we live. However, some bacteria remain difficult to treat or detect, and the emergence of resistant strains, and their rapid spread in our globalized societies, have considerably reduced our antibiotic arsenal. Epidemic outbreaks can regularly have severe health and economic consequences. Rapid detection and identification of these bacteria therefore remains a major challenge.
The approach we are developing is based on metabolic marking of the cell surface. For example, the outer wall of Gram-negative bacteria is covered by a compact layer of lipopolysaccharides (LPS), which play a role not only in cell integrity, but also in the virulence of certain strains.
Our recent work has shown that, when metabolically active, Gram-negative bacteria can specifically incorporate within their LPS a monosaccharide chemically modified by the introduction of an "azide" group. This bioorthogonal indicator function can then be used to "reveal" labeled bacteria, using a ligation method such as " click chemistry ". This approach enables rapid detection of live pathogenic bacteria.
This seminar will present our main results in this field, including the development of a strategy for the specific labeling of Legionella pneumophila, the bacterium responsible for Legionnaire's disease, and a method for concentrating bacterial samples.
