Esteban, Jaime

SUMMARY Periprosthetic joint infection (PJI) is a significant complication of arthroplasty. Implicit in the diagnosis of PJI is the presence of organisms in what should be a sterile milieu. Given limits to culture-based PJI diagnosis, optimal utilization of culture in the diagnostic approach to PJI needs clarification. Culture is important in confirming a PJI diagnosis and characterizing the infecting microorganism(s) to inform management. As part of the development of a unified definition of PJI (by a group representing multiple scientific societies), a systematic review was performed to inform the role of culture in the definition of PJI. In addition, a comprehensive review on synovial fluid and periprosthetic tissue collection for culture, and associated culture methodology and results interpretation, was performed to inform best practices. Gaps in the literature were identified to develop research priorities.

Abstract Background Cutibacterium species are common pathogens in periprosthetic joint infections (PJI). These infections are often treated with β-lactams or clindamycin as monotherapy, or in combination with rifampin. Clinical evidence supporting the value of adding rifampin for treatment of Cutibacterium PJI is lacking. Methods In this multicenter retrospective study, we evaluated patients with Cutibacterium PJI and a minimal follow-up of 12 months. The primary endpoint was clinical success, defined by the absence of infection relapse or new infection. We used Fisher’s exact tests and Cox proportional hazards models to analyze the effect of rifampin and other factors on clinical success after PJI. Results We included 187 patients (72.2% male, median age 67 years) with a median follow-up of 36 months. The surgical intervention was a 2-stage exchange in 95 (50.8%), 1-stage exchange in 51 (27.3%), debridement and implant retention (DAIR) in 34 (18.2%), and explantation without reimplantation in 7 (3.7%) patients. Rifampin was included in the antibiotic regimen in 81 (43.3%) cases. Infection relapse occurred in 28 (15.0%), and new infection in 13 (7.0%) cases. In the time-to-event analysis, DAIR (adjusted hazard ratio [HR] = 2.15, P = .03) and antibiotic treatment over 6 weeks (adjusted HR = 0.29, P = .0002) significantly influenced treatment failure. We observed a tentative evidence for a beneficial effect of adding rifampin to the antibiotic treatment—though not statistically significant for treatment failure (adjusted HR = 0.5, P = .07) and not for relapses (adjusted HR = 0.5, P = .10). Conclusions We conclude that a rifampin combination is not markedly superior in Cutibacterium PJI, but a dedicated prospective multicenter study is needed.