Cells and Materials


Gram-positive coagulase-negative staphylococci have been implicated in breast prosthesis infection. Staphylococcus au re us, Staphylococcus epidermidis, and Staphylococcus hominis strains were examined for adhesion and proliferation morphology to polyurethane foam and smooth silicone rubber prosthetic biomaterials. Ruthenium red, alcian blue and ruthenium red-lysine in en bloc procedures were applied to optimally visualize the polysaccharide slime. Ruthenium red processing resulted in observation of additional outer material close to the cell wall, more than seen in the absence of cationic reagent. Alcian blue preserved fibrous or netlike strands or meshworks of material. Ruthenium red-lysine preserved considerable amounts of slime covering the cocci as well as extending between them and the prosthetic surface. Elongate strands of slime appeared to facilitate attachment to the substrate and projection of cells away from the substrate. Where this material was lacking, cell mass buildup was required for projection from the substrate. The amount of fibrous material observed corresponded to levels of slime production known for each staphylococci strain. Some extracellular material was observed for even the classified "non-slime" S. hominis strain SP2. The ruthenium red-lysine approach was optimal for visualization of slime for all bacterial species in this study.