P03

The Drosophila melanogaster (Dm) has shown to be a good experimental model to study TB, using Mycobacterium marinum infection. It has provided an important insight on the innate immunity response, as insects rely solely on this type of response thus avoiding the variability that adaptive mechanisms imply. Also due to the high homology of the genes that determine it with humans: approximately sharing a 75% of genetical homology. We have used this model to characterize how the fast-growing Mycolicibacterium manresensis, an environmental, non-pathogenic mycobacteria able to induce a protective immune response against subsequent infections with Mycobacterium tuberculosis (Mtb) in mammals, interacts with its host. We have infected systemically both male and females flies with M. manresensis, M. marinum and Mycobacterium smegmatis, a pathogenic and a non-pathogenic mycobacteria respectively. We have then compared the virulence of the three species in this host by assessing the survival, the tissue damage, and the innate immune response of the host. We have also evaluated the replication ability of the three species both in vivo and in vitro using the S2 cell line. Results showed that M. manresensis has a high capacity to replicate within the host, kills the flies faster than the virulent species M. marinum, and triggers a higher innate immune response in the host.