ADHESION OF STAPHYLOCOCCUS-EPIDERMIDIS AND TRANSPOSON MUTANT STRAINS TO HYDROPHOBIC POLYETHYLENE

Staphylococcus epidermidis capsular polysaccharide adhesin (PS/A) and slime were studied as possible mediators of bacterial adhesion to NHLB I polyethylene (PE) under dynamic flow. This putative interaction was examined by quantifying the adhesion of M187 (PS/A+, slime+) parent st rain and isogenic transposon mutant strain sn3 (PS/A-, slime-) to poly ethylene (PE) under a range of physiologic shear stress conditions in both phosphate-buffered saline (PBS) and 1% platelet poor plasma (PPP) . No significant differences in adhesion were noted between the M187 a nd sn3 strains in either test medium. However, adhesion of both strain s in 1% PPP was decreased 75-95% compared to adhesion in PBS. In PBS, adhesion was shear stress dependent from 0-15 dyne/cm(2), after which adhesion was comparatively shear stress independent. Adhesion in 1% PP P was independent of shear stress. Epifluorescent imaging of both stra ins labeled for slime confirmed the presence of slime on the surface o f M187 and suggested that PS/A and slime promote the formation of larg e aggregates, as aggregates were totally absent in the images of the s n3 strain. The results suggest that PS/A and slime do not mediate S. e pidermidis adhesion to bare PE or PE with adsorbed plasma proteins, bu t may be necessary for intercellular adhesion, which is important for biofilm formation. (C) 1998 John Wiley & Sons, Inc.