This
in-vitro study determines the elution kinetics of strategies commonly used to achieve local therapeutic levels of antibiotics to eradicate
biofilms. Antibiotic-loaded STIMULAN beads, antibiotic loaded PMMA cement spacer and powered vancomycin as a bolus were investigated using an in-vitro flow reactor model to simulate clinical drainage rates to those measured after knee surgery. Samples of effluent were collected and analysed to determine vancomycin efficacy against
S. aureus UASM-1, using the zone of inhibition test. Initially the bolus had the highest potency, however within 1 hour this potency had diminished. The antibiotic spacer also peaked and was washed out within the hour, however as the flow rate of the model slowed it allowed the concentration to increase again at 16 hours. Antibiotic loaded STIMULAN beads alone or in combination with a loaded spacer showed the highest levels of potency peaking within one hour but maintaining therapeutic levels over an extended period compared to the bolus and spacer alone.
