Periprosthetic
infection (PI) causes significant morbidity and mortality after fixation and joint
arthroplasty and has been extensively linked to the formation of bacterial biofilms.
Poly(methyl methacrylate) (
PMMA), as a cement or as beads, is commonly used for
antibiotic release to the site of
infection but displays variable elution kinetics and also represents a potential nidus for
infection, therefore requiring surgical removal once
antibiotics have eluted. Absorbable cements have shown improved elution of a wider range of
antibiotics and, crucially, complete biodegradation, but limited data exist as to their antimicrobial and antibiofilm efficacy. Synthetic
calcium sulfate beads loaded with
tobramycin,
vancomycin, or
vancomycin-
tobramycin dual treatment (in a 1:0.24 [wt/wt] ratio) were assessed for their abilities to eradicate planktonic methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis relative to that of
PMMA beads. The ability of the
calcium sulfate beads to prevent biofilm formation over multiple days and to eradicate preformed biofilms was studied using a combination of viable cell counts, confocal microscopy, and scanning electron microscopy of the bead surface. Biofilm bacteria displayed a greater tolerance to the
antibiotics than their planktonic counterparts.
Antibiotic-loaded beads were able to kill planktonic cultures of 10(6) CFU/ml, prevent bacterial colonization, and significantly reduce biofilm formation over multiple days. However, established biofilms were harder to eradicate. These data further demonstrate the difficulty in clearing established biofilms; therefore, early preventive measures are key to reducing the risk of PI. Synthetic
calcium sulfate loaded with
antibiotics has the potential to reduce or eliminate biofilm formation on adjacent periprosthetic tissue and
prosthesis material and, thus, to reduce the rates of periprosthetic
infection.