title: Novel clues on the specific association of Streptococcus gallolyticus subsp gallolyticus with colorectal cancer.
abstract: BACKGROUND
  The prevalence of Streptococcus gallolyticus subsp gallolyticus ( Streptococcus bovis biotype I) endocarditis is in general low but very often linked to colorectal cancer. Therefore, this study aimed to reveal the virulence characteristics that distinguish this opportunistic pathogen from a panel of (closely related) intestinal bacteria.
  
  
  METHODS
  The route of infection was reconstructed in vitro with adhesion, invasion, and translocation assays on differentiated Caco-2 cells. Furthermore, cellular immune responses upon infection and bacterial biofilm formation were analyzed in a comparative manner.
  
  
  RESULTS
  S. gallolyticus subsp gallolyticus strains were demonstrated to have a relative low adhesiveness and could not internalize epithelial cells. However, these bacteria were uniquely able to paracellularly cross a differentiated epithelium without inducing epithelial interleukin 8 or 1β responses. Importantly, they had an outstanding ability to form biofilms on collagen-rich surfaces, which in vivo are found at damaged heart valves and (pre)cancerous sites with a displaced epithelium.
  
  
  CONCLUSIONS
  Together, these data show that S. gallolyticus subsp gallolyticus has a unique repertoire of virulence factors that facilitate infection through (pre)malignant colonic lesions and subsequently can provide this bacterium with a competitive advantage in (1) evading the innate immune system and (2) forming resistant vegetations at collagen-rich sites in susceptible patients with colorectal cancer.
authors: Department of Laboratory Medicine, Nijmegen Institute for Infection, Inflammation and Immunity, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors: Annemarie
authors: A
authors: Boleij
authors: Carla M J
authors: CM
authors: Muytjens
authors: Sarah I
authors: SI
authors: Bukhari
authors: Nadège
authors: N
authors: Cayet
authors: Philippe
authors: P
authors: Glaser
authors: Peter W M
authors: PW
authors: Hermans
authors: Dorine W
authors: DW
authors: Swinkels
authors: Albert
authors: A
authors: Bolhuis
authors: Harold
authors: H
authors: Tjalsma
mesh_terms: D001422:Bacterial Adhesion; D018441:Biofilms; D018938:Caco-2 Cells; D003094:Collagen; D015179:Colorectal Neoplasms / Q000382:microbiology*; D016207:Cytokines / Q000378:metabolism; D004847:Epithelial Cells / Q000276:immunology; D019073:HT29 Cells; D006801:Humans; D013290:Streptococcal Infections / Q000150:complications* / Q000382:microbiology*; D013291:Streptococcus / Q000472:pathogenicity*; D014774:Virulence
chemical_list: D016207:Cytokines; D003094:Collagen