Differential importance of protein and polysaccharide intercellular adhesin mediated biofilm formation in Staphylococcus aureus and Staphylococcus epidermidis from prosthetic joint infections
Abstract number: o95
Rohde H., Burandt E., Frommelt L., Siemssen N., Burdelski C., Wang C.-J., Scherpe S., Knobloch J.K.-M., Kaplan J., Mack D.
Nosocomial staphylococcal foreign-body infections are a major problem in modern medicine, demanding new therapeutic and preventive strategies. The usefulness of known virulence factors as vaccine candidates is critically restricted by their prevalence in natural staphylococcal populations. As biofilm formation is essential for the pathogenesis of Staphylococcus epidermidis and Staphylococcus aureus foreign-body infections this study examined the distribution of genes involved in biofilm formation, the biofilm phenotype and production of polysaccharide intercellular adhesin (PIA) in clonal independent S. aureus and S. epidermidis strains isolated from persistent prosthetic joint infections after total hip arthroplasty (THA) or total knee arthroplasty (TKA).
A biofilm-positive phenotype was detected in all S. aureus and 69.2 % of S. epidermidis strains. There were no major differences in the distribution of factors mediating primary attachment between S. aureus and S. epidermidis strains from TKA and THA. icaADBC, encoding the synthesis apparatus for PIA, was detected in all S. aureus strains, but 38.5% of S. epidermidis strains were icaADBC-negative. 50 % of those produced trypsin sensitive biofilms, indicating that in these strains protein factors like the highly prevalent accumulation associated protein (Aap) is sufficient for intercellular adhesion. Protease-sensitive biofilms were exclusively found in S. epidermidis strains from THA, representing 37 % of all biofilms in this population. In contrast, both trypsin and PIA-cleaving dispersin B disintegrated S. aureus biofilms, indicating that in this species PIA and proteins act cooperatively in biofilm formation regardless of the infection site.
Our findings suggest that PIA and protein factors are of differential importance for the pathogenesis of S. epidermidis in PJI after THA and TKA, implicating icaADBC cannot serve as a general virulence marker in this species. In S. aureus biofilm formation proteins are of overall importance and future work should focus on the identification of functionally active molecules.
|Session name:||XXIst ISTH Congress|
|Back to top|