Anahita Mostaghim^1,, Hoi Yee Annie Lo¹, Nancy Khardori²

This study aims to analyze duration of intravenous antimicrobial treatment and targeted antimicrobial choices after narrowing from broad-spectrum antibiotics in cases of infective endocarditis (IE) at a large teaching hospital in the U.S. Patients were retrospectively identified from 2007-2015 using appropriate ICD-9 codes. Cases that met definite Modified Duke Criteria were extracted for epidemiologic data, causative organism, antimicrobial regimen choice and length, mortality, and recurrence. Patients treated with at least 6 weeks of intravenous antibiotics had less recurrence than those who received less than 6 weeks (0% vs 9.5%, P = 0.0081) with all cases of recurrence being with Staphylococcal IE. Cefazolin showed a lower in-hospital mortality than nafcillin for methicillin-sensitive staphylococcus aureus (3.3% vs 41.2%, P = 0.0118) although statistically insignificant in coagulase negative staphylococcus IE (16.7% vs 66.7%, P = 0.0992). Cefazolin and vancomycin had similar in-hospital mortality for methicillin-susceptible coagulase-negative staphylococcus (16.7% vs 22.2%). Daptomycin and vancomycin had similar in-hospital mortality in methicillin-resistant S. aureus (0% vs 6.3%). Vancomycin and ampicillin had similar in-hospital mortalities in susceptible enterococcus (16.7% each). Recurrence was tied to use of less than 6 weeks of antibiotics in cases of staphylococcal IE. Cefazolin had lower in-hospital mortality than nafcillin in cases of methicillin-susceptible S. aureus and coagulase-negative staphylococcus. Vancomycin showed similar efficacy to cefazolin, daptomycin, and ampicillin in their respective susceptible species. Randomized control trials need to be held to confirm if antibiotic choice is tied to in-hospital mortality.

infective endocarditis, antibiotic, cefazolin, nafcillin, duration, mortality, recurrence