As a result of the distinct behaviour of the isolates from non-human sources, we will also focus on the comparison of human and animal isolates to further elaborate potential differences in infection mechanisms. The specific clinical association with gastrointestinal neoplasia due to S. bovis biotype I or S. gallolyticus, respectively

[7–9] strongly imply that S. gallolyticus enter the human body via the gastrointestinal tract through sites with decreased intestinal barrier function such as colonic malignancies. Unfortunately, a correlation between the number of existing virulence genes, biofilm formation, invasion and adhesion characteristics with the presence Hedgehog inhibitor or absence of colonic malignancies can barely be created with the small number of available patient data at present. Indeed, the bacterial translocation is the first important step in the development of IE before colonizing the endothelium, and mechanisms of adherence to and invasion

of epithelial cells play an important role during this initial phase of infection. Therefore, our future investigations will also address this important mechanism to potentially disclose clues on specific features of individual S. gallolyticus strains. In conclusion, this is the first description of S. gallolyticus adhesion to and invasion of human endothelial cells. The established in vitro model provides a convenient system to evaluate differences in the virulence characteristics of different strains. Binding to ECM proteins and biofilm formation INK 128 mouse provide additional information for strain characterization. The first identification of a possible pilus-associated gene in S. gallolyticus

supplemented the so far limited availability of possible virulence factors. This study provides important initial characterization of variability and behaviour of the as yet barely analyzed endocarditis pathogen S. gallolyticus. Acknowledgements We thank Sarah L. Kirkby for her linguistic advice. This work was supported by the “”Forschungsfoerderung der Medizinischen Fakultaet der Ruhr-Universitaet Bochum (FoRUM), Grant F606-2007. References 1. Naber CK, Bauhofer A, Block M, Buerke M, Erbel R, Graninger W, Herrmann M: S2-Leitlinie zur Diagnostik und Therapie der infektiösen Endokarditis. Z Kardiol 2004, 93:1005–1021.PubMedCrossRef 2. Sillanpää J, Nallapareddy SR, Singh KV, Ferraro however MJ, Murray BE: Adherence characteristics of endocarditis-derived Streptococcus gallolyticus ssp. gallolyticus ( Streptococcus bovis biotype I) isolates to host extracellular matrix proteins. FEMS Microbiol Lett 2008,289(1):104–109.PubMedCrossRef 3. Schlegel L, Grimont F, Ageron E, Grimont PA, Bouvet A: Reappraisal of the taxonomy of the Streptococcus bovis / Streptococcus equinus complex and related species: description of Streptococcus gallolyticus subsp. gallolyticus subsp. nov., S. gallolyticus subsp. macedonicus subsp. nov. and S. gallolyticus subsp. pasteurianus subsp. nov.