Characterization of the importance of Staphylococcus epidermidis autolysin and polysaccharide intercellular adhesin in the pathogenesis of intravascular catheter-associated infection in a rat model

A rat central venous catheter (CVC) infection model was used to assess the importance of the proteinacious autolysin (AtlE) and the polysaccharide intercellular adhesin (PIA) in the pathogenesis of Staphylococcus epidermidis CVC-associated infection. Wild-type (wt) S. epidermidis O-47 was significantly more likely to cause a CVC infection than was either of the isogenic mutant strains (AtlE- negative [O-47mut1] or PIA-negative [O-47mut2]). Bacteria were retrieved from the explanted catheters of 87.5% of rats inoculated with S. epidermidis O-47, compared with 25% of rats challenged with either S. epidermidis O-47mut1 or O-47mut2 (P = .007). Peripheral bacteremia was documented in 75% of rats challenged with S. epidermidis O-47, compared with 12.5% and 25% challenged with O-47mut1 and O-47mut2, respectively (P = .009). Metastatic disease was more common in rats inoculated with wt S. epidermidis, compared with AtlE- or PIA-deficient mutants. These results confirm the importance of initial adherence, associated with AtlE, and biofilm production, mediated by PIA, in the pathogenesis of S. epidermidis experimental CVC infection.