Introduction: Staphylococcus epidermidis is a leading coagulase-negative pathogen in periprosthetic joint infection (PJI), but the outcome impact of key resistance phenotypes is unclear.

Methods: We retrospectively studied consecutive monomicrobial S. epidermidis PJIs treated at a tertiary hospital (2010–2024). PJI was defined by 2018 ICM criteria. Success required infection eradication without suppressive antibiotics or further infection-related surgery after ≥12 months. 

Results: Among 516 evaluable PJIs, 105 (20.3%) were monomicrobial PJI due to S. epidermidis. Mean age was 71 and 56% were women; 51% involved the knee and 49% the hip. Chronic infection accounted for 79%. Surgical strategies were DAIR in 27.6%, one-stage exchange in 28.6%, and two-stage exchange in 39.0%. Overall success was 78.1% (DAIR 75.9%, one-stage 93.3%, two-stage 73.2%). Resistance rates were methicillin 72.3%, fluoroquinolone 53.3%, rifampin 24.8%, and multidrug resistance or extensively drug resistant (MDR/XDR) 43.8%. Rifampin resistance (73.1% vs 91.3%, p=0.021) and MDR/XDR (67.4% vs 84.7%, p=0.035) were associated with failure; methicillin (p=0.853) and fluoroquinolone resistance (p=0.129) were not.

Conclusion: Rifampin-resistant and MDR/XDR S. epidermidis PJIs represent higher-risk infections and should prompt early optimization of biofilm-active therapy and surgical source control. This is, to our knowledge, the largest single-center series focused exclusively on monomicrobial S. epidermidis PJI across hip and knee.

 

Short Summary

We studied hip and knee prosthetic joint infections  caused by Staphylococcus epidermidis, a common pathogen that can form biofilm on implants. We reviewed over one hundred cases to understand how antibiotic resistance affects treatment success. We found that infections resistant to rifampin, levofloxacin or multiple antibiotics showed a higher failure rate. These findings may help surgeons choose the best surgical and antibiotic treatment approach for patients.