986. Pseudomonas Prosthetic Joint Infections: Is there a role for monotherapy?

Background Pseudomonas species are a less common but devastating pathogen family in prosthetic joint infections (PJI). Despite advancements in management, Pseudomonas PJI remains particularly difficult to treat due to fewer antibiotic options and robust biofilm formation. The purpose of this study was to better evaluate outcomes after Pseudomonas PJI treatment. Methods All hip or knee PJIs, at a single institution, with positive Pseudomonas culture were analyzed. 51 patients (29 hips and 22 knees) meeting inclusion criteria were identified. The primary outcome of interest was infection clearance at 1-year after surgical treatment, defined as reassuring aspirate without ongoing antibiotic treatment or death within one year post-operatively. Monomicrobial and polymicrobial infections were evaluated separately. Results Among monomicrobial PJIs, ten (50.0%) patients were clear of infection at one year post-operatively. Patients treated with 2-stage exchange (n=11) had a 1-year clearance rate of 54.5% compared to 60.0% with DAIR (n=5) and 25.0% with resection or amputation (n=4). Two of six patients treated with fluoroquinolone monotherapy met 1-year infection clearance, despite fluoroquinolone sensitivity, compared to four of five patients meeting 1-year clearance when treated with combined intravenous and oral therapy for at least 6 weeks. Resistance to anti-pseudomonal agents was infrequent (20%, n=4/20), and three of ten mono- and polymicrobial PJI patients with recurrent Pseudomonas PJI developed resistance to anti-pseudomonal therapy. Polymicrobial infections were the most common presentation (54.9%) of Pseudomonas positive PJI with a mortality rate of 46.4% (n=13/28) at a median follow-up of 4.2 years [IQR: 3.4-5.7]. Conclusion Despite surgical and antibiotic treatment regimens consistent with traditional treatment algorithms, our data portrays poor clearance rate of Pseudomonas PJI with relatively poor outcomes in patients treated with oral or intravenous monotherapy. Pseudomonas infections are difficult to eradicate and likely require deviations from classical therapeutic protocols to improve treatment success. Disclosures William A. Jiranek, MD, Biomech Holdings LLC: Stocks/Bonds|DePuy, A Johnson & Johnson Company: IP royalties Thorsten M. Seyler, MD, PhD, Heraeus: Paid consultant|Pattern Health: IP royalties|Restor3d: IP royalties|Smith & Nephew: Paid consultant|Total Joint Orthopedics: Paid consultant|Zimmer: research.