CLINICAL OUTCOME OF PATIENTS WITH ACUTE PERIPROSTHETIC JOINT INFECTIONS CAUSED BY PSEUDOMONAS AERUGINOSA COMPARED TO OTHER GRAM-NEGATIVE BACILLI

Aim Pseudomonas aeruginosa is considered as more difficult to treat than other Gram-negatives in patients with acute periprosthetic joint infections (PJIs). However, clinical data to support this hypothesis are lacking. Therefore, this study aims to evaluate a cohort of patients with an early acute PJI and compare the clinical outcome of those cases caused Pseudomonas aeruginosa and those caused by Enterobacterales. Method This retrospective multicenter cohort study included 39 patients with an early acute knee or hip PJI caused by Pseudomonas aeruginosa and 84 control patients with another Gram-negative bacillus (i.e., Enterobacterales). Both groups were managed by surgical debridement, antibiotics, and implant retention (DAIR). Treatment failure within one-year follow-up was defined as prosthesis extraction, a clinical need for suppressive antibiotic treatment and/or PJI-related death. Results Median age was 75 years (IQR 64-82) in cases and 74 years (IQR 65-83) in control patients (p=0.598). Distribution of affected joints, and revision versus primary arthroplasties, did not differ between groups. Most PJIs were polymicrobial (87% in cases, 81% in control patients, p = 0.451). Surgical and antibiotic management was similar between groups. Treatment failure did not differ between groups: 5/39 cases (12.8%) and 14/84 control patients (16.7%, p = 0.610). Conclusions An acceptable success rate of acute PJI caused by P. aeruginosa when treated with DAIR was observed. This success rate did not differ compared to PJIs caused by Enterobacterales. Therefore, Pseudomonas aeruginosa should not be considered a more difficult to treat microorganism compared to other Gram-negatives. No additional surgical or antimicrobial interventions are needed when patients can be treated with a fluoroquinolone