FEDER - UNICAEN - RNAMB - INVEST
Kohesio
UNIVERSITE DE CAEN NORMANDIE
The term “Microbiota designates complex microbial communities and is today at the center of multiple concerns. In the human body, where the microbial population is estimated at 1.5 kg, or 1014 microorganisms and 10 times more than human eukaryotic cells, there are 2 main microbiota, the intestinal microbiota (1 kg) and the skin microbiota (200 g). The intestinal microbiota has been extensively studied but it is only much more recently that the structure and functions of the skin microbiota have been addressed, in particular under pressure from the cosmetic industry. We also find an airborne microbiota linked to aerosols, essential in the diffusion of pathogens, and in foods where it participates in both their maturation and their spoilage. These microbiota are composed of bacteria but also molds (fungal microbiota), yeasts and viruses. Certain viruses (bacteriophages, targeting bacteria) are suspected of playing an essential role on the dynamics of the bacterial microbiota, and therefore on the final technological and health qualities of foods. In different environments and as soon as they are in contact with stable surfaces, microorganisms organize themselves in the form of biofilms which can be considered as “transient tissues within which they produce an extracellular matrix and communicate by chemical or even electrical signals. This development in the form of biofilms is associated with significant physiological modifications which generally give microorganisms increased resistance to biocides. The enbiofilm growth of bacteria such as Pseudomonas aeruginosa, Acinetobacter baumannii or Legionella pneumophila is thus associated with increased resistance to antibiotics and the development of highly morbid chronic infections, as in the case of cystic fibrosis. At the same time, in the environment the development of microbial biofilms leads to modifications of the surface of materials and to their alteration (corrosion), or even as in the case of marine biofilms (biofouling), to the attachment of undesirable organisms (invertebrates, algae, etc.) or to the contamination of foods. The modifications of microorganisms linked to the transition from the planktonic (free) lifestyle to the biofilm lifestyle have been the subject of studies on germs isolated or on model biofilms that are generally simple or reconstituted from a limited number of species, whereas in reality biofilms present a very great diversity. On the other hand, there are transient or permanent life forms of microorganisms on surfaces such as the skin which, with a few exceptions, do not really seem to be biofilm-structured but nevertheless imply a high level of adaptation to their micro and macroenvironment. It has thus been shown that signals from the host (hormones, neurohormones) and atmospheric pollutants (NO2) can be detected by microorganisms (bacteria) and modulate their virulence and their capacity to form biofilms. It is therefore necessary in a large number of cases to study the composition and functionality of real complex microbiota, whether in free form (air), in interaction with their host (skin) or parasites (bacteriophages) and their environment (atmospheric pollutants of the NO2 type) and in the form of biofilms (food) in order to better understand their positive and/or deleterious effects and if necessary define new active ingredients making it possible to control health safety, well-being and food sustainability. This last objective involves the characterization of the regulatory mechanisms involved in the formation of these microbiota. This project is therefore based on the development of specific high-throughput screening techniques.
Smarter Europe / Research and innovation / Research and innovation infrastructure (public)