(578) Necrotizing Soft Tissue Infections and Choice of Empiric Vancomycin Plus Clindamycin or Linezolid

Introduction: Necrotizing skin and soft tissue infections (NSTIs) are life-threatening infections that require prompt diagnosis, antibiotics, and surgical intervention. Clindamycin or linezolid is recommended as adjunct for treatment of NSTIs by consensus guidelines for toxin-mediation. There is limited data comparing clindamycin-based regimens to linezolid-based regimens in patients with NSTI.

Methods: This single-center, retrospective cohort study included adults with NSTI who received either clindamycin or linezolid as part of combination therapy while admitted to the intensive care unit (ICU) at the University of Kentucky HealthCare for surgical debridement between January 2017 and June 2023. Patients were excluded if they received antibiotics for < 24 hours, underwent surgical debridement at an outside hospital, or were readmitted within the study period such that the first admission was included. The primary outcome was number of surgical debridements before source control. Secondary outcomes included time to source control, rates of acute kidney injury (AKI), ICU length of stay, and antibiotic duration.

Results: 242 patients with NSTI were included with 199 receiving clindamycin and 43 receiving linezolid. There was no difference in number of surgical debridements between clindamycin versus linezolid ([2.0 (2,4) vs. 3.0 (2, 4)]; p =0.219). The multivariate regression identified independent variables that predicted a significant increase in number of debridements, including admission SOFA score [1.03 (1.003, 1.047); p=0.028], culture(s) positive for Streptococcus anginosus, Streptococcus constellatus, or Streptococcus intermedius [1.309 (1.042, 1.629); p=0.018], and culture(s) positive for Bacteroides species [1.301 (1.048, 1.602); p=0.015). There were no differences in AKI ([53.8% vs. 60.8%], p=0.424), ICU length of stay ([5.3 vs. 6.1 days]; p=0.399), or duration of antibiotics ([5.6 vs. 6.7 days]; p=0.683).

Conclusions: Linezolid-based regimens resulted in a similar number of surgical debridements compared to clindamycin-based regimens in patients with NSTI. The only factors found to significantly increase the number of debridements included admission SOFA score, culture(s) positive for Streptococcus anginosus, Streptococcus constellatus, Streptococcus intermedius, or Bacteroides species.