First description of Staphylococcus lugdunensis internalisation into epithelial cells

Abstract number: P1308

Szabados F., Heck B., Rodepeter S., Kaase M., Kleine B., Sakinc T., Schmitz I., Gatermann S.

Objectives:Staphylococcus lugdunensis belongs to coagulase-negative Staphylococci(CoNS) and can occasionally cause serious invasive infections such as osteomyelitis and infective endocarditis. S. lugdunensis accounts for 18% of infective endocarditis and 44% of native valve endocarditis caused by CoNS. S. lugdunensis expresses potential virulence factors, including synergistic toxins, haemolysins, extracellular enzymes, several adhesion factors, which mediate binding to collagen type I and IV, human IgG, fibronectin and fibrinogen. Furthermore, a fibrinogen-binding protein (Fbl), with a high homology to clumping factor A of S. aureus has been described.

We therefore sought to investigate internalisation of several S. lugdunensis blood culture isolates into different epithelial cell lines.

Methods: Internalisation into the human bladder carcinoma cell line 5637 and Hep2 cells were measured using a FACS-based method as described previously. The bacteria were stained with FITC and were incubated for one hour with the cells, gentamicin and lysostaphin was added for half an hour. The cells were washed and treated with trypsin to remove adhering bacteria and to detach the eukaryotic cells. For further discrimination, a gating strategy was used, because bacteria were smaller in size and FITC stained.

Results: The internalisation of several S. lugdunensis blood culture isolates was significantly increased in contrast to non-invasive S. carnosus TM 300. Internalisation ratio was slightly less compared to S. aureus Cowan I strain.

Conclusion: Our experiments demonstrate for the first time internalisation of S. lugdunensis clinical isolates into epithelial cells in a FACS invasion assay. These results were in line with the clinical suspected invasive ability of this pathogen. Internalisation into eukariotic cells could explain an important step of S. lugdunensis pathogenicity in serious infections e.g. endocarditis in analogy to mechanisms described for S. aureus.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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