Recurrent relapsing remitting Serratia marcescens infective endocarditis in a former drug-using patient

Unusual course of Serratia marcescens (SM) infectious endocarditis (IE) and literature review (2016-2024; 26 cases). A 44-year-old man, with chronic venous ulcers, presented 21/2 years after a MSSA tricuspid valve IE, a tricuspid and aortic valves SM IE . After 6 weeks of antibiotherapy (meropenem i.v., 2 g/6 h), he presented a relapse (same sensitivity pattern), complicated by tibio-peroneal trunk aneurysm. He underwent a biological tricuspid valve replacement. Fifteen months later, he presented a recurrent SM IE, (same sensitivity pattern), complicated by a popliteal artery aneurysm. An aortic-tricuspid bioprosthetic valve replacement was performed. At one-year, there was no sign infection. The occurrence of both relapsing and recurrence, and of infectious aneurysms in SM IE are highlighted. However, these findings must be interpreted with caution, due to the lack of molecular typing. Literature shows that a regimen combining a beta-lactam and either fluoroquinolone or an aminoglycoside seems to warrant a less mortality rate.