LAUSR

Abstract Background Injection drug use (IDU) is a major risk factor for infective endocarditis (IE). Rates of IE have recently increased in the US concurrent with the opioid crisis. Although IDU-related IE is well described, few data exist on repeat IE (rIE) in persons who inject drugs (PWID). Methods Patients ≥18 years old seen at Wake Forest Baptist Medical Center from 2004–2017 with an ICD-9 or -10 diagnosis of IE who met Duke criteria for IE and who self-reported IDU in the 3 months prior to admission were identified. The subset of PWID who developed rIE, defined as another episode of IE at least 10 weeks after the diagnosis of the first episode, was then reviewed. Results Of the 94 PWID with IE, 22 (23.4%) experienced rIE (19 re-infections, three relapses). All patients were Caucasian, 50% were male, and 68.2% lived in rural areas; the median age was 30. All 22 patients resumed IDU after their first episode of IE. The mean duration from completion of antibiotics for the prior IE episode to admission with rIE was 257.5 days; the episode of rIE occurred within 1 year in 17 patients (77.3%). On repeat admission, those with rIE had a Pitt bacteremia score of 3.0 and an APACHE II score of 13.1. Fever and bacteremia persisted for an average of 5.6 days and 2.6 days, respectively. S. aureus was the cause of rIE in 54.5% of patients and the tricuspid valve (TV) was involved in 77.3% of cases. Valve surgery occurred in 22.7% of patients. Mean length of stay was 25.3 days and mean duration of antibiotic therapy was 32.1 days. Seven patients (31.8%) died during the rIE hospitalization and another died within 12 months after discharge resulting in a 1-year mortality of 36.3%. Compared with their first episode of IE, rIE patients had higher admission Pitt bacteremia (3.0 vs. 1.5, P = 0.07) and APACHE II scores (13.1 vs. 9.5, P = 0.18), fewer S. aureus infections (54.5% vs. 95.4%, P = 0.01), similar TV involvement (77.3% vs. 72.7%, P = 1), and less frequent surgery (22.7% vs. 59.1%, P = 0.06). Conclusion rIE is common in PWID with most episodes occurring within 1 year of the initial episode. Reinfection is more frequent than relapse. The microbiology of rIE is more varied than first episode IE in PWID with S. aureus being less frequently isolated. Illness severity is high, hospitalizations are prolonged, and 1-year mortality is significant. More effective strategies for preventing rIE in PWID are needed. Disclosures J. Peacock, Pfizer: Shareholder, Owns common stock in Pfizer which was inherited and held in a trust.