Periprosthetic Joint Infections Caused by Enterococci Have Poor Outcomes.

BACKGROUND: The definitive treatment and outcome of periprosthetic joint infection (PJI) caused by Enterococcus species is unknown. We performed a multi-institutional study to analyze the characteristics and treatment outcomes of patients with enterococcal PJI and to define an effective treatment protocol. METHODS: We retrospectively reviewed all PJIs at 3 institutions between 1999 and 2014 using an electronic query followed by manual chart review. We included patients who met the Musculoskeletal Infection Society's criteria for PJI and had at least 1 positive intraoperative culture for any Enterococcus species. We identified 87 patients who had 12-month follow-up or treatment failure (mean, 4.03 years). Treatment failure was based on Delphi consensus criteria described previously. Kaplan-Meier survivorship analyses were performed. We assumed an alpha level of 0.05 for statistical significance. RESULTS: The overall incidence of enterococcal PJI was 4.2%. The overall treatment success rate was 51.7% (45 of 87 patients). Thirteen cases (14.9%) that failed treatment had adverse outcomes including salvage procedures and PJI-related mortality. Treatment success rates stratified by procedure were 62.8%, 39.4%, and 45.5% for 2-stage exchange arthroplasty, irrigation and debridement, and 1-stage exchange arthroplasty, respectively (P = .037). Antibiotic treatment was heterogeneous; although combination antibiotics demonstrated a trend toward higher treatment success, it was not statistically different from monotherapy regimens (P = .174). CONCLUSION: Enterococcal PJI has a high rate of treatment failure. Surgeons and patients should be aware of the difficulty in managing this condition and its dismal treatment outcomes. Although antibiotic treatment was heterogeneous, there was a trend toward higher success rates when combination antibiotic therapy was used.