Infection prevalence and patterns in self-inflicted gunshot wounds to the face.

Objective: Self-inflicted gunshot wounds (SIGSWs) to the craniomaxillofacial region are uncommon injuries but are associated with a high mortality rate. Therefore, treating these patients is a rare occurrence even in the largest trauma centers. As with many rare conditions, data specifically addressing this injury pattern are scarce. Because of the proximity of the blast, even low-velocity injuries can be associated with significant avulsion of tissue, comminution of structures, and tissue die back. Previous case reports have recommended the use of prophylactic antibiotics, but no study has specifically investigated the postinjury infection rate or microbial patterns in this patient population. The purpose of this study was to answer the following clinical question: "Among patients with SIGW to the maxillofacial region, what is the prevalence of postinjury infection, and are there any microbial patterns that can guide empiric antibiotic selection?"

Study Design: We designed retrospective cohort study at a level I trauma center in Portland, Oregon. Data on 17 patients who had sustained a SIGSW involving the maxilla or the mandible and survived their initial injury were collected from 2010 to 2017.

Results: Patients who had a culture-positive infection within 30 days of their injury were defined to have a postinjury infection. Six of the 17 patients (35%) developed a postinjury infection, with an average time to infection of 11 days from initial injury (range 3-19 days). Of the 17 subjects, 15 (88%) received a course of prophylactic antibiotics, on average, for 14 days (range 3-24 days). Of the 6 cases of postinjury infection, culture grew gram-negative bacteria in 4 cases-anaerobic bacteria in 2 and polymicrobial organisms in 2. There was no clear pattern or prevalence of any specific bacterium, but cultures notably included Staphylococcus aureus, Enterobacter species, Bacteroides species, and Escherichia coli.

Conclusions: SIGSWs are associated with a high rate of postinjury infection (35%) despite prophylactic antibiotic usage in 88% of these cases. Given the antimicrobial patterns observed in this study, prophylactic antibiotics in this patient population should include empiric coverage for gram-negative and anaerobic bacteria.