Bacterial growth on articulating spacers: an in vitro study

We fashioned cement disk-shaped spacer models using antibiotic-loaded Palacos and embedded polyethylene and titanium into the surface of half of the models and inoculated the models with methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant S aureus (MRSA), or Staphylococcus epidermidis, and placed them in nutrient broth. Vancomycin was loaded into the cement of the MRSA spacer models and tobramycin into the MSSA and Staphylococcus epidermidis models. In the MSSA and MRSA models, no organisms survived beyond 48 hours in the antibiotic bath regardless of the presence of additional materials. At 96 hours, 86.6% of models with only antibiotic cement had viable Staphylococcus epidermidis, while 80% of models with antibiotic cement, polyethylene, and titanium had viable Staphylococcus epidermidis. Adding polyethylene and titanium to antibiotic-loaded cement does not promote bacterial survival.