Recurrent Bioprosthetic Valve Serratia marcescens Endocarditis in Intravenous Drug Users

BACKGROUND We report 2 cases of recurrent right-sided endocarditis in 2 young patients known to be intravenous (i.v.) drug users. We highlight the importance of early diagnosis and management, especially in recurrent infection, which has a higher mortality rate and poor prognostic outcome despite antibiotic treatment. CASE REPORT A 30-year-old woman with a medical history of active i.v. drug use and tricuspid valve replacement owing to Serratia marcescens endocarditis 2 months prior to presentation was admitted to the Intensive Care Unit for septic shock. The patient did not respond to i.v. fluids and required vasopressors. Blood cultures returned positive for S. marcescens again. The antibiotic regimen consisted of meropenem and vancomycin. The patient underwent redo sternotomy, explant of old tricuspid valve bioprosthesis, debridement of tricuspid valve annulus, and bioprosthetic valve replacement. She continued antibiotic treatment during hospital admission for 6 weeks. In another similar case, a 30-year-old woman, also an i.v. drug user, was admitted to the hospital for tricuspid bioprosthetic valve S. marcescens endocarditis after tricuspid valve replacement 5 months prior to her presentation with S. marcescens endocarditis. Her antibiotic regimen consisted of meropenem and vancomycin. She was eventually transferred to a tertiary cardiovascular surgery center for further case management. CONCLUSIONS In the setting of recurrent bioprosthetic valve S. marcescens endocarditis, it is suggested that treatment should be more focused on source control, including cessation of i.v. drug abuse and providing appropriate antibiotic treatment to prevent recurrence because, in the case of recurrence, morbidity and mortality risk can increase significantly.