Patterns of Bacterial Infections Following Orthopedic Surgeries: A Retrospective Analysis

Background and objective Surgical site infections (SSIs) following orthopedic procedures are associated with significant morbidity and continue to pose an ongoing clinical challenge. Pathogen patterns vary by surgical category and may not be adequately covered by standard perioperative antibiotic prophylaxis, which has remained largely unchanged for decades. This study aimed to characterize pathogen distribution patterns across different orthopedic surgical categories and to evaluate whether current prophylactic regimens align with the observed microbiological profile. Methods This retrospective single-center study included 98 patients who developed SSIs involving implanted hardware following elective, semi-elective, or trauma-related orthopedic surgeries. Inclusion criteria required a positive wound culture obtained using a sterile technique during the first surgical debridement. Results The mean age of the cohort was 68.5 years. The mean interval from primary surgery to debridement and irrigation was 67.1 days. Patients undergoing elective arthroplasty presented at a chronic stage, with a mean interval of 132 days. The most frequently isolated pathogen was methicillin-sensitive Staphylococcus aureus (MSSA; n = 23, 23.5%, 95% confidence interval (CI): 16.2%-32.9%). Gram-negative organisms predominated in spine surgeries, accounting for 69% of isolates (n = 9/13, 95% CI: 39.5%-88.1%). The trauma and femur fracture groups were predominantly infected with Gram-positive organisms. Mixed Gram-positive and Gram-negative bloodstream infections were detected in 14% of blood cultures (n = 14, 95% CI: 8.7%-22.6%), exclusively in the femur fracture and trauma groups. Conclusions Pathogen patterns differ substantially across orthopedic surgical categories. The predominance of Gram-negative organisms in spine SSIs suggests that further investigation of pathogen-specific prophylactic strategies in spine surgery may be warranted. Prospective studies are needed to determine whether targeted adjustments to prophylactic regimens can effectively decrease SSI rates in spine surgery.