Nisin F-loaded brushite bone cement prevented the growth of Staphylococcus aureus in vivo

Aims: To determine if nisin F‐loaded self‐setting brushite cement could control the growth of Staphylococcus aureus in vivo. Methods and Results: Brushite cement was prepared by mixing equimolar concentrations of β‐tricalcium phosphate and monocalcium phosphate monohydrate. Nisin F was added at 5·0, 2·5 and 1·0% (w/w) and the cement moulded into cylinders. In vitro antibacterial activity was determined using a delayed agar diffusion assay. Release of nisin F from the cement was determined using BCA protein assays. Based on scanning electron microscopy and X‐ray diffraction analysis, nisin F did not cause significant changes in cement structure or chemistry. Cement containing 5·0% (w/w) nisin F yielded the most promising in vitro results. Nisin F‐loaded cement was implanted into a subcutaneous pocket on the back of mice and then infected with S. aureus Xen 36. Infection was monitored for 7 days, using an in vivo imaging system. Nisin F prevented S. aureus infection for 7 days and no viable cells were isolated from the implants. Conclusions: Nisin F‐loaded brushite cement successfully prevented in vivo growth of S. aureus. Significance and Impact of the Study: Nisin F incorporated into bone cement may be used to control S. aureus infection in vivo.