191 - oral versus Intravenous Antibiotic Treatment in Skin and Soft Tissue Infections as a Consequence of Intravenous Drug Use: A Retrospective Study to Demonstrate Noninferiority

Background: Skin and soft tissue infections (SSTIs) are among the most prevalent infectious complications of intravenous drug use (IVDU). Given its polymicrobial nature, studies focusing on SSTIs in the general population may not be generalizable this group. We completed a retrospective chart review to better characterize the safety and efficacy of oral versus intravenous (IV) antibiotics for the treatment SSTIs in IVDU.

Methods: We reviewed patients admitted with bacterial SSTIs and IVDU from January 01, 2012 to December 31, 2019 based on ICD-10 codes. SSTIs complicated by bacteremia, endocarditis, bone or joint involvement on index admission were excluded. Patients who received < 48 hours of IV antibiotics were considered oral therapy, otherwise they were considered IV therapy. Patient comorbidities, incision and drainage (I&D) status, substance use, microbiology and antimicrobial data were reviewed.

Results: Of 231 eligible patients, 84 received oral therapy. There was no statistical difference in patient characteristics between the two therapy groups. Streptococcus anginosus group were the most common organisms found (33%) followed by Staphylococcus aureus (31%). There was no statistical difference between rates of readmission (p=0.87), recurrent primary site infection (p=1.00), repeat debridement (p=0.08) or occurrence of deep-seated infections within 90 days of treatment completion. No morality was observed. The oral group had shorter length of stay (3 vs. 5 days, p < 0.001) and shorter total duration of antibiotics (10 vs. 13 days, p < 0.001). Overall, 90% of those with abscess underwent I&D, which did not differ between therapy groups. Time to I&D was shorter (0 vs. 1 day, p=0.005) in the oral group. Patients who did not receive and I&D were more likely to be readmitted within 90 days (p=0.025).

Conclusion: In SSTIs related to IVDU, oral antibiotic therapy was noninferior to IV in terms of mortality, readmission, and deep-seated infection rates within 90 days of treatment completion and had a decreased length of stay and total treatment duration. A delay in I&D led to increased length of stay and lack of I&D increased readmission rate. Therefore, a prompt I&D may allow a safe and effective early transition to oral therapy in SSTIs related to IVDU.