The inhibition of bacterial adhesion to a tobramycin-impregnated polymethylmethacrylate substratum

Tobramycin sulfate powder (1.2 g) was mixed with Palacos polymethylmethacrylate (PMMA) bone cement (40 g) to produce 100 discs containing 5.9 mg tobramycin per disc. These discs were used to evaluate the inhibition of bacterial adhesion to an antibiotic-laden biomaterial. Tobramycin-impregnated PMMA discs and control discs containing no tobramycin were exposed in vitro to Staphylococcus epidermidis. Colonization was quantitated using plate count techniques and electron microscopy. Tobramycin-impregnated surfaces reduced adhesive bacteria colonization by 1 log relative to control discs. These observations suggest that tobramycin-impregnated PMMA may not be significantly effective in preventing colonization of the biomaterial substratum and PMMA may be a poor choice as a drug delivery vehicle in biomaterial and compromised tissue-centered infections.