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Two main research subjects

Published on 2 October 2019

© V. Job

Study of Type III Secretion System (T3SS): Assembly, regulation and function
The T3SS delivers toxins directly in the cytoplasm of target cells; it is recognized as the most potent virulence factor of P. aeruginosa. Our group studied several components of the T3SS machinery, their action on host cell and their regulation. In total we expressed 13 proteins of the T3SS, and obtained antibodies against all of them. For the majority of the corresponding genes, we engineered unmarked mutants in cytotoxic strains and analyzed their main phenotypes. We notably study the T3 translocon, which is inserted within the host cell membranes and facilitates toxin passage from bacterial to the eukaryotic cytoplasm. In addition, we determined various actions of the T3SS toxins once in the host.

Novel virulence strategies of clinical P. aeruginosa strains

In 2011, in collaboration with the Microbiology and Intensive Care Units in the Grenoble University Hospital, we screened a cohort of P. aeruginosa strains that caused ventilator-associated pneumonia. This work led to:

• Genetic characterization of a new type of clinically relevant strains that do not possess T3SS
• Demonstration that these strains are capable of hyper-virulence by provoking hemorrhagic pneumonia
• Identification of a novel secreted toxin that we named Exolysin.