Microbiological profile and susceptibility pattern of surgical site infections related to orthopaedic trauma

Understanding the epidemiology of microorganisms associated with surgical site infections related to orthopaedic trauma (SSI-ROT) is important in establishing treatment protocols. The aim of this study was to evaluate the etiology and susceptibility pattern of SSIs related to orthopaedic trauma in a Brazilian reference hospital for trauma.

Patients with SSI-ROT in a Brazilian reference hospital for trauma were retrospectively analyzed. All patients with orthopaedic trauma who underwent a surgical procedure and developed SSI within one year were included. All patients had culture samples from the surgical site obtained from biopsy of bone or soft tissue. Clinical and epidemiological data of the patients were collected.

A total of 147 patients with trauma-related infection were included in the analysis. The mean time to infection was 55.5 days, and the mean duration of hospitalization was 20.0 days. The in-hospital mortality rate after infection was 5.4%. Cultures were obtained from all patients, with 104 samples obtained from soft tissues and 43 samples from bone. The positivity rate was 93.2%. Among the isolates, 56.5% (77 patients) were gram-negative bacteria and 43.8% (60 patients) were gram-positive bacteria. Staphylococcus aureus was identified in 34%, Enterobacter spp. in 14.9%, and Pseudomonas aeruginosa in 11.6%. Staphylococcus aureus presented a higher positivity in bone samples (odds ratio, 1.29; 95% CI, 1.01-1.70; p = 0.04). Few microorganisms were multi-resistant.

SSI in orthopaedic trauma can be associated with gram-negative bacilli, the susceptibility profile of which suggested that most infections occur after discharge. Staphylococcus aureus infections were commonly caused by methicillin-susceptible isolates, and this susceptibility to oral antibiotic options helps in the dehospitalization of patients.