The joint environment and periprosthetic joint infection

ABSTRACT Peri-prosthetic joint infections (PJI) are devastating complications of joint replacements. Prevention of infection remains the best strategy as once a PJI has established, it is difficult to cure and recurrence rates exceed 17%. Immediately following surgery, the joint implants are bathed in a post-operative serosanguinous fluid (SSF)

which over time changes to a viscous, protein- and proteoglycan-rich joint fluid. Our data show differences in antibiotic sensitivity, bacterial adhesion, and myeloid cell function between synovial fluid (SynF), serum, and serum dilutions that approximate wound fluid/SSF. Importantly, our data suggest that the fluid composition

across this evolution differentially modulates bacterial adherence, antibiotic sensitivity, and by implication, immune response. Excitingly, our data further suggest that application of ultrasound-triggered microbubble disruption (UTMD) can impact bacterial metabolism to enhance the antibiotic sensitivity that was lost with the

evolution of the joint fluid. Thus, we hypothesize that a “golden window” exists in which the post-operative SSF permits eradication of contaminating bacteria through the combined actions of antibiotics and the immune response while the transition to SynF limits the efficacy of both. We further propose that this golden window

can be enhanced and extended through the use of UTMD to activate bacterial metabolism. We will (1) determine the effects of SSF and SynF fluid on antibiotic activity and myeloid cell function, (2) determine UTMD effects on bacterial eradication and myeloid function in SSF and SynF joint fluid and (3) prevent PJI in vivo through

combined microbubble/antibiotic treatments. This information will be used to create combination therapies that will prevent PJI in vivo. Importantly, our novel strategy will seamlessly integrate with current clinical infection mitigation strategies and can be immediate translated into a new therapeutic approach for prevention of PJI.