Title : Shigella strain has developed non-studied pathogenicity mechanisms of adaptability in the colonization of epithelial cells
In order to contribute to the understanding of the mechanism of invasion of epithelial cells by Shigella sp., we have first shown (i) Shigella strains as well as clinical or environmental strains are able to secrete biosurfactant-like molecules (BLM) directly in the extracellular medium in aerobic and anaerobic conditions. Second, we have shown that the secretion of biosurfactants-like molecule depends on type three secretion system (T3SS). (ii) Shigella bacteria are able to swarm on semisolid media under anaerobic and aerobic conditions; (iii) Shigella bacteria are able to form biofilms under anaerobic and aerobic conditions; (iv) biosurfactants produced by Shigella are considered involved in biofilm formation in Shigella spp; (v) there is a correlation between bacterial concentration, the ability to secrete biosurfactants and the ability of strains to form biofilms; (vi) Shigella bacteria are unable to invade cells under anaerobic conditions; (vii) secretion of biosurfactants in the absence of oxygen occurs under leaky SST3 conditions. Our study suggests that the biosurfactant with lipopeptide or peptide features, stable at 40°C, could play an outstanding role in Shigella pathogenicity mechanisms including bacteria–host cell interaction, cell metabolism, and cell dissemination. This work contributes to the understanding of pathogenicity of Shigella strains.