Heterogeneous expression of Pil3 pilus is critical for Streptococcus gallolyticus translocation across polarized colonic epithelial monolayers

Mariana Martins (1) , Laurence Du Merle (1) , Patrick Trieu-Cuot (1) , Shaynoor Dramsi (1)

1 BBPG+ - Biologie des Bactéries pathogènes à Gram-positif - Biology of Gram-Positive Pathogens

Streptococcus gallolyticus is an opportunistic pathogen responsible for septicemia and endocarditis. We report that S. gallolyticus UCN34 adheres and crosses epithelial monolayers in a Pil3 dependent manner. Confocal images revealed a paracellular passage. Both the Δpil3 mutant and the Pil3+ overexpressing variant were unable to cross Caco-2 and T84 barriers. However, combining live Δpil3 mutant with fixed Pil3+ variant in a 9:1 ratio allowed efficient translocation of the Δpil3 mutant. These results demonstrate that heterogeneous expression of Pil3 plays a key role for UCN34 translocation across the intestinal barrier. Through this skilful strategy, S. gallolyticus probably evade host immune responses.

Mots clés: Colon; Pil3 pilus; S. bovis; Streptococcus gallolyticus; Translocation

Domaines: Sciences du Vivant [q-bio]

Mariana Martins, Laurence Du Merle, Patrick Trieu-Cuot, Shaynoor Dramsi. Heterogeneous expression of Pil3 pilus is critical for Streptococcus gallolyticus translocation across polarized colonic epithelial monolayers. Microbes and Infection, 2020, 22 (1), pp.55-59. ⟨10.1016/j.micinf.2019.12.001⟩. ⟨pasteur-03262258⟩