Defining the Optimal Antibiotic Duration in Necrotizing Skin and Soft Tissue Infections: Clinical Experience from a Quaternary Referral Center.

Background: Early initiation of broad-spectrum antibiotic agents is a cornerstone of the care of necrotizing skin and soft tissue infections (NSTI). However, the optimal duration of antibiotic agents is unclear. We sought to characterize antibiotic prescribing patterns for patients with NSTI, as well as associated complications. Patients and Methods: Using an NSTI registry, we characterized antibiotic use at a quaternary referral center. Kaplan-Meier analyses were used to describe overall antibiotic duration and relative to operative source control, stratified by presence of other infections that independently influenced antibiotic duration. Factors associated with successful antibiotic discontinuation were identified using logistic regression. Results: Between 2015 and 2018, 441 patients received antibiotic agents for NSTI with 18% experiencing a complicating secondary infection. Among those without a complicating infection, the median duration of antibiotic administration was 9.8 days (95% confidence interval [CI], 9.2-10.5) overall, and 7.0 days after the final debridement. Perineal NSTI received fewer days of antibiotic agents (8.3 vs. 10.6) compared with NSTI without perineal involvement. White blood cell (WBC) count and fever were not associated with failure of antibiotic discontinuation, however, a chronic wound as the underlying infection etiology was associated with greater odds of antibiotic discontinuation failure (odds ratio [OR], 4.33; 95% CI, 1.24-15.1). Conclusions: A seven-day course of antibiotic agents after final operative debridement may be sufficient for NSTI without any secondary complicating infections, because clinical characteristics do not appear to be associated with differences in successful antibiotic discontinuation.