Osteosynthesis-associated infection of the lower limbs by multidrug-resistant and extensively drug-resistant Gram-negative bacteria: a multicentre cohort study

Abstract

Purpose: The purpose of this study was the clinical and therapeutic assessment of lower-limb osteosynthesis-associated infection (OAI) by multidrug-resistant (MDR) and extensively drug-resistant (XDR) Gram-negative bacteria (GNB), which have been poorly studied to date. Methods: A prospective multicentre observational study was conducted on behalf of ESGIAI (the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group on Implant-Associated Infections). Factors associated with remission of the infection were evaluated by multivariate and Cox regression analysis for a 24-month follow-up period. Results: Patients ( n = 57) had a history of trauma (87.7 %), tumour resection (7 %) and other bone lesions (5.3 %). Pathogens included Escherichia coli ( n = 16), Pseudomonas aeruginosa ( n = 14; XDR 50 %), Klebsiella spp. ( n = 7), Enterobacter spp. ( n = 9), Acinetobacter spp. ( n D 5), Proteus mirabilis ( n = 3), Serratia marcescens ( n = 2) and Stenotrophomonas maltophilia ( n = 1). The prevalence of ESBL (extended-spectrum fi -lactamase), fluoroquinolone and carbapenem resistance were 71.9 %, 59.6% and 17.5% respectively. Most patients ( n = 37; 64.9 %) were treated with a combination including carbapenems ( n = 32) and colistin ( n = 11) for a mean of 63.3 d. Implant retention with debridement occurred in early OAI (66.7 %), whereas the infected device was removed in late OAI (70.4 %) ( p = 0.008). OAI remission was achieved in 29 cases (50.9 %). The type of surgery, antimicrobial resistance and duration of treatment did not significantly influence the outcome. Independent predictors of the failure to eradicate OAI were age > 60 years (hazard ratio, HR, of 3.875; 95% confidence interval, CI95 %, of 1.540-9.752; p D 0 :004) and multiple surgeries for OAI (HR of 2.822; CI95% of 1.144-6.963; p = 0.024). Conclusions: Only half of the MDR/XDR GNB OAI cases treated by antimicrobials and surgery had a successful outcome. Advanced age and multiple surgeries hampered the eradication of OAI. Optimal therapeutic options remain a challenge.