J. W. Keyloun1,2, R. L. Ball1,2, J. R. Chen See4,5, M. A. Oliver1, B. C. Carney1, M. M. McLawhorn1,2, J. R. Wright4,5, R. Lamendella4,5, L. T. Moffatt1,3, J. W. Shupp1,2,3 1MedStar Health Research Institute,Firefighters’ Burn And Surgical Research Laboratory,Washington, DC, USA 2Washington Hospital Center,The Burn Center, Department Of Surgery,Washington, DC, USA 3Georgetown University School of Medicine,Departments Of Surgery And Biochemistry,Washington, DC, USA 4Juniata College,Department Of Biology,Huntingdon, PA, USA 5Wright Labs, LLC,Huntingdon, PA, USA
Introduction: Burn patients are at high risk for wound infection. Early excision and grafting and advances in antimicrobial dressings have improved patient outcomes. The judicious use of systemic antibiotics to treat infected burn wounds and sepsis is essential for burn patients. However, the use of routine perioperative antibiotics is debated. Perioperative antibiotics may alter the patient microbiome and promote resistance without improving outcomes. The objective of this study is to investigate the effect of perioperative antibiotics on burn wound bacterial microbiome and clinical outcomes.
Methods: Patients with uncomplicated thermal burns of <10% TBSA expected to require a single grafting procedure were eligible for enrollment. Patients were randomized to receive a single dose of weight-based cefazolin on induction of anesthesia or no antibiotics, which is our standard-of-care. Blood, saliva, wound biopsies, and swabs were collected before and after wound excision for quantitative culture and microbiome (16S rRNA) analysis. Repeat samples were collected at the first dressing takedown (1-3 days post-grafting), and first follow-up visit postoperatively (7-10 days post-discharge).
Results: Demographics and injury characteristics are presented in Table 1 (n=28 patients). Median time between admission and operative intervention was 2 (IQR, 2-3) days. Patients who received antibiotics had significantly lower wound bed biopsy (0, IQR, 0-3.8×103 CFU/g vs. 7.0×104, 0-2.5×109 CFU/g; p=0.02) and swab (0, 0-0 CFU/mL vs. 4.2×102, 0-1.3×104 CFU/mL; p=0.001) bacterial cultures compared to patients who did not receive antibiotics. There was no significant difference between groups on wound bed or donor site bacterial cultures intraoperatively or at follow up. There was one intraoperative post-excision biopsy and one swab that was culture positive in the antibiotics and no antibiotics group respectively. Groups did not differ significantly in rates of graft loss, postoperative infection, or %re-epithelialization at follow-up. Linear discriminant analysis effect size (LEfSe) revealed 31 enriched bacterial taxa within the wound beds of patients who received antibiotics based on dressing takedown samples (LDA ≥ 2, p ≤ 0.05).
Conclusion: Early excision and grafting and topical antimicrobials are effective at reducing the risk of burn wound infection. Perioperative antibiotics reduce wound bed bacterial colonization at the first postoperative dressing change but do not alter clinical outcomes. Microbiome analysis suggests that a single dose of perioperative antibiotics alters the wound bed microbiome, which may result in the enrichment of pathogenic bacteria.
