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Genetics of Biofilms Unit

Jean-Marc Ghigo
Most of what has been learned about bacterial physiology derives from the study of pure, free-floating laboratory cultures where bacteria adopt a planktonic lifestyle. However, from clear-running water to dental plaques, it is now recognized that in most ecosystems, microorganisms predominate as biofilms, matrix-encased and heterogeneous communities of microorganisms that develop on inert and biological surfaces.
Biofilms are often detrimental in medical and industrial settings and the phenotypic analysis of biofilm versus planktonic bacteria indicate that biofilms display particular biological properties that distinguish them from their planktonic counterparts. We use genetic, genomic and molecular biology approaches combined with a microfermenter-based experimental model to study the biofilm lifestyle.
The primary objectives of the research carried on in the laboratory aim at the identification of the bacterial factors necessary for the formation and the maintenance of mature biofilms (identification of biofilm-specific genes). We also investigate the specific functions that could be performed in this environment (horizontal gene transfer, cell to cell adhesion, bacterial communication between pathogenic and commensal strains of E. coli). The characterization of such biofilm factors or functions is realized mostly using the model organism Escherichia coli. However, the regulation of biofilm formation is also investigated through close collaborations in other microorganisms such as Salmonella enteritidis, Klebsiella pneumoniae, Staphylococcus aureus, Candida albicans et Candida glabrata. These approaches may lead to a better understanding of the biofilm lifestyle and help design new strategies to control or limit the extent of pathogenic or detrimental biofilms in situations where they represent a sanitary, industrial or ecological problem.