Insights into Streptococcus agalactiae PI-2b pilus biosynthesis and role in adherence to host cells

Bruno Périchon (1) , Julie Guignot (2) , Noémi Szili (1) , Cherry Gao (1) , Claire Poyart (2, 3) , Patrick Trieu-Cuot (1) , Shaynoor Dramsi (1)

1 BBPG+ - Biologie des Bactéries pathogènes à Gram-positif - Biology of Gram-Positive Pathogens
2 Barrières et Pathogènes
3 Centre national de Référence des Streptocoques (CNR)

The core PI-2b pilus present in "hypervirulent" ST-17 Streptococcus agalactiae strains consists of three pilin subunits (Spb1, Ap1 and Ap2) assembled by sortase SrtC1 and cell-wall anchored by Srt2. Spb1 was shown to be the major pilin and Ap2 the anchor pilin. Ap1 is a putative adhesin. Two additional genes, orf and lep, are part of this operon. The contribution of Lep and Ap1 to the biogenesis of the PI-2b pilus was investigated. Concerning the role of PI-2b, we found that higher PI-2b expression resulted in higher adherence to human brain endothelial cells and higher phagocytosis by human THP1 macrophages.

Keywords: THP-1 phagocytosis; PI-2b pilus; GBS; S. agalactiae; Group B Streptococcus

Domains: Bacteriology

Bruno Périchon, Julie Guignot, Noémi Szili, Cherry Gao, Claire Poyart, et al.. Insights into Streptococcus agalactiae PI-2b pilus biosynthesis and role in adherence to host cells. Microbes and Infection, 2019, 21 (2), pp.99-103. ⟨10.1016/j.micinf.2018.10.004⟩. ⟨pasteur-02863685⟩