440. Necrotizing Soft-Tissue Infections Involving Actinomyces Species

BACKGROUND: Actinomyces sp. are associated with numerous clinical diseases in humans; however, there are few case reports of necrotizing soft-tissue infections (NSTIs) involving these organisms. Their role in NSTIs has not been well described. At our medical center, we noted an increase in Actinomyces sp. isolated from the tissue specimens of patients with NSTIs, prompting further evaluation. METHODS: Microbiology databases were utilized to identify patients with clinical cultures growing Actinomyces sp. from January 2008 to December 2018. Adult patients admitted to the R Adams Cowley Shock Trauma Center with a diagnosis of NSTI were included for analysis. RESULTS: Nine patients were identified meeting inclusion criteria, the first in February 2018–none prior. Organisms isolated from culture included Actinomyces turicensis (n = 3), Actinomyces europeaus (n = 1), and five organisms identified only as Actinomyces species. 89% of patients had additional co-pathogens identified in their tissue cultures. Eight patients had NSTIs of the lower extremity (n = 5) and/or the genitourinary area (n = 6), and one had chronic decubitus ulcers. Comorbidities included diabetes mellitus (77%), chronic kidney disease (33%). 44% patients were in septic shock at presentation. Surgical debridement was performed in all patients. Eight patients were discharged on amoxicillin, with a mean treatment duration of 75 days (range 31–90). One patient was treated with ampicillin–sulbactam. Readmission rate at 90 days was 37%; only one was related to the index infection. One death occurred during the index hospitalization, secondary to NSTI. No patients experienced adverse drug reactions during therapy. CONCLUSION: We describe one of the largest case series to date of Actinomyces sp. associated with NSTI. The startling appearance of Actinomyces sp. at our institution directly followed the implementation of matrix-assisted laser desorption/ionization time of flight mass spectrometry in January 2018. Actinomyces sp. may act as co-pathogens contributing to the severity of NSTIs, augmenting the virulence of other organisms. As more advanced technology is used in laboratories to identify these organisms, further study is needed to determine pathogenicity and appropriate treatment. DISCLOSURES: All authors: No reported disclosures.