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One of these studies, conducted in 2016, compared gene expression by transcriptomics of the host R. microsporus ATCC 52813 with or without its native Burkholderia endobacterium and the non-host strain with or without Burkholderia bacteria, showed that symbiosis with the bacteria leads to specific changes in the fungal lipid metabolism, mediated by diacylglycerol kinase enzymes, which ultimately lead to an accumulation of triacylglycerol (TAG) and phosphatidylethanolamine (PE). This disruption of lipid metabolism plays a role in modifying the biophysical properties of the membrane and may influence virulence related to fungal-macrophage interaction. ---- In another study, they demonstrated that the Burkholderia endosymbiont controls host sexual reproduction, leading to successful fungal mating and production of B-carotene pigments, through transcriptional control of the fungal gene ras2, which encodes a GTPase central to fungal reproductive development. ----- A recent transcriptomics study in 2020 showed that endosymbiosis causes changes in the regulation of different genes related to cell wall remodelling, stress response such as ROS and the cyclic AMP pathway, while in bacteria there are changes in genes related to secretion systems. These changes can affect both antifungal susceptibility and virulence. All these studies indicate that endosymbiosis interferes with fungal gene regulation and may have an impact on pathogenesis. ----- Objectives: So, in this context, our objective is evaluating the impact of bacterial-fungal interaction on antifungal susceptibility and virulence by determination of MIC of different antifungals and virulence in vitro and in vivo. Methodology: First of all, the strains used in this study are ATCC 52813 and ATCC 52814 strains of Rhizopus microsporus that contain endobacteria naturally in their mycelia and the strain ATCC 11559 don’t contain endobacteria. For analyse antifungal susceptibility, we first obtain host strains without bacteria by antibiotic treatment with ciprofloxacin and then determine the MIC of the different antifungals, a host strain with its endobacterium, the same strain cured of its endobacterium by antibiotic treatment and non-host strains of endobacteria naturally will be used. The determination of MIC will be performed by the CLSI microdilution technique using different antifungals such as azoles, echinocandins and novel compounds. For analyse antifungal susceptibility, we first obtain host strains without bacteria by antibiotic treatment with ciprofloxacin and then determine the MIC of the different antifungals, a host strain with its endobacterium, the same strain cured of its endobacterium by antibiotic treatment and non-host strains of endobacteria naturally will be used. The determination of MIC will be performed by the CLSI microdilution technique using different antifungals such as azoles, echinocandins and novel compounds. ----- In addition, virulence studies in murine macrophages will be carried out following the same strategy as previously mentioned with the strains by phagocytosis assay and ROS assay for detect cellular stress. Depending on the results of the in vitro virulence, mouse studies could also be carried out. ----- So far, we have only made a preliminary determination of MIC against 3 azoles. In 5-day cultures on YPG medium, the non-host strain ATTCC11559 had more sporulation than others two strains with endobacteria. Moreover, the nonhost strain showed lower mic for VRC than the host strains, but in case of Itraconazol, we observed then contrary. this has been all, Thank you for your attention/time If you have any questions, I will be delighted to answer it.