Clinical characteristics and risk factors of recurrence for Pseudomonas aeruginosa-associated fracture-related infection following surgical treatment : a 12-year retrospective cohort study.

Abstract

<i>Pseudomonas aeruginosa</i> (PA), a prevalent Gram-negative pathogen in fracture-related infections (FRIs), presents huge therapeutic challenges due to biofilm formation and multidrug resistance (MDR). Evidence-based guidelines for PA-associated FRI (PA-FRI) remain limited. The aim of the present study was to delineate the clinical characteristics of PA-FRI and associated risk factors of recurrence, and to provide actionable insights for optimizing antibiotic stewardship, refining surgical protocols, and reducing the burden of PA-FRI recurrence. This retrospective cohort study examined 147 cases of PA-FRI involving limb fractures treated at our centre from January 2012 to December 2023. Demographic, microbiological, and clinical parameters were evaluated with ≥ 24-month follow-up. Multivariate regression analysis was conducted to identify risk factors for recurrence. The cohort (mean age 45.06 years (SD 13.83)) showed a predominance of tibial fractures (69.4%; 102 out of 147). MDR-PA prevalence increased from 33.3% (2012 to 2014) to 58.6% (2021 to 2023), accounting for 44.9% (n = 66) of isolates. Coinfection with <i>Staphylococcus aureus</i> occurred in 17 cases (11.6%). Initial debridement and antibiotic therapy achieved infection control in 132 cases (89.8%), with persistence in 10.2% (n = 15). At a median 36-month follow-up (IQR 30 to 48), recurrence occurred in 15.6% (n = 23) after documented resolution of infection. Nine patients (6.1%) required amputation, while the remaining 14 achieved infection-free union. Multivariate logistic regression identified the following risk factors for recurrence: post-debridement internal fixation (odds ratio (OR) 4.85 (95% CI 1.00 to 23.36)); multiple prior debridements (two or more) (OR 6.00 (95% CI 1.02 to 35.37)); MDR-PA infection (OR 11.33 (95% CI 1.95 to 65.91)); long-term polymethylmethacrylate spacer retention (OR 9.32 (95% CI 2.08 to 41.80)); and shorter duration (less than four weeks) of systemic antibiotics (including intravenous and oral) (OR 7.84 (95% CI 2.02 to 30.40)). Delayed surgical intervention (more than ten weeks from the time of initial injury to the index debridement surgery) was associated with a reduced risk of recurrence compared with acute/sub-acute interventions (OR 0.16 (95% CI 0.04 to 0.63)). The high MDR prevalence and recurrence rates underscore persistent challenges in PA-FRI. This study identifies key modifiable risk factors and establishes a risk-stratified framework to guide preoperative optimization, antimicrobial stewardship, and surgical decision-making.