Evaluation of infection rates with narrow versus broad-spectrum antibiotic regimens in civilian gunshot open-fracture injury

Introduction: Civilian gunshot open-fracture injuries portray a significant health burden to patients. Use of antibiotics is endorsed by guideline recommendations for the prevention of post-traumatic infections, however, antimicrobial selection and their associated outcomes remains unclear. Therefore, we sought to compare infectious and other clinical outcomes between three antimicrobial cohorts in patients with gunshot-related fractures requiring operative intervention. Materials and methods: Patients were identified by retrospectively querying the University of Kentucky Trauma Registry for gunshot wound victims. A narrow regimen, an expanded gram-negative regimen, and a regimen containing a fluoroquinolone antimicrobial were identified for comparison. The primary outcome was a composite of infections at or before 14 days of hospitalization. Secondary endpoints included hospital length of stay, incidence of multidrug resistant bacteria and methicillin-resistant Staphylococcus aureus colonization, number of drug-related adverse events, number of Clostridium difficile infections, and 30-day mortality. Results: 252 patients were selected for inclusion: 126 in the narrow regimen, 49 in the expanded gram-negative regimen, and 77 in the fluoroquinolone-based regimen. There were no statistical differences in the primary endpoint of early infectious outcomes between groups (p = 0.1797). The expanded gram-negative regimen was associated with increased hospital length of stay, and increased incidence of multi-drug resistant bacteria and methicillin-resistant Staphylococcus aureus colonization. There were no statistically significant differences in any of the remaining secondary endpoints. Conclusion: In this study evaluating civilian gunshot trauma, broad spectrum antibiotic coverage was not associated with improvements in post-traumatic infections. A randomized trial is needed to confirm these results.