Serine-Rich Repeat Proteins and Pili Promote Streptococcus agalactiae Colonization of the Vaginal Tract
- 15 December 2011
- journal article
- Published by American Society for Microbiology in Journal of Bacteriology
- Vol. 193 (24), 6834-6842
- https://doi.org/10.1128/jb.00094-11
Abstract
Streptococcus agalactiae(group B streptococcus [GBS]) is a Gram-positive bacterium found in the female rectovaginal tract and is capable of producing severe disease in susceptible hosts, including newborns and pregnant women. The vaginal tract is considered a major reservoir for GBS, and maternal vaginal colonization poses a significant risk to the newborn; however, little is known about the specific bacterial factors that promote GBS colonization and persistence in the female reproductive tract. We have developedin vitromodels of GBS interaction with the human female cervicovaginal tract using human vaginal and cervical epithelial cell lines. Analysis of isogenic mutant GBS strains deficient in cell surface organelles such as pili and serine-rich repeat (Srr) proteins shows that these factors contribute to host cell attachment. As Srr proteins are heavily glycosylated, we confirmed that carbohydrate moieties contribute to the effective interaction of Srr-1 with vaginal epithelial cells. Antibody inhibition assays identified keratin 4 as a possible host receptor for Srr-1. Our findings were further substantiated in anin vivomouse model of GBS vaginal colonization, where mice inoculated with an Srr-1-deficient mutant exhibited decreased GBS vaginal persistence compared to those inoculated with the wild-type (WT) parental strain. Furthermore, competition experiments in mice showed that WT GBS exhibited a significant survival advantage over the ΔpilAor Δsrr-1mutant in the vaginal tract. Our results suggest that these GBS surface proteins contribute to vaginal colonization and may offer new insights into the mechanisms of vaginal niche establishment.Keywords
This publication has 59 references indexed in Scilit:
- Bacterial Pili exploit integrin machinery to promote immune activation and efficient blood-brain barrier penetrationNature Communications, 2011
- Chlamydial Infection Increases Gonococcal Colonization in a Novel Murine Coinfection ModelInfection and Immunity, 2011
- The surface protein HvgA mediates group B streptococcus hypervirulence and meningeal tropism in neonatesThe Journal of Experimental Medicine, 2010
- Vaginal microbiome of reproductive-age womenProceedings of the National Academy of Sciences of the United States of America, 2010
- Mycoplasma genitalium Rapidly Disseminates to the Upper Reproductive Tracts and Knees of Female Mice following Vaginal InoculationInfection and Immunity, 2010
- The Streptococcus pneumoniae adhesin PsrP binds to Keratin 10 on lung cellsMolecular Microbiology, 2009
- Molecular Dissection of the secA2 Locus of Group B Streptococcus Reveals that Glycosylation of the Srr1 LPXTG Protein Is Required for Full VirulenceJournal of Bacteriology, 2009
- The Group B Streptococcal Serine‐Rich Repeat 1 Glycoprotein Mediates Penetration of the Blood‐Brain BarrierThe Journal of Infectious Diseases, 2009
- A group B streptococcal pilus protein promotes phagocyte resistance and systemic virulenceThe FASEB Journal, 2008
- The Surface Protein Srr-1 of Streptococcus agalactiae Binds Human Keratin 4 and Promotes Adherence to Epithelial HEp-2 CellsInfection and Immunity, 2007