(228) Rare Case of Strep salivarius-associated ICD Lead Infection and Right-Sided Infective Endocarditis

Introduction: Infective endocarditis, occurring in 15 per 100,000 people, is often caused by viridans streptococci (40-60% of cases). Streptococcus salivarius, less common (2-7% incidence), affects systems beyond the GI tract and poses diagnostic challenges with 31% penicillin resistance. Limited literature exists on concurrent ICD lead infection and right-sided endocarditis by this organism. We present a case of infective endocarditis mimicking failure to thrive in an older male, successfully treated with infected hardware removal and extended IV antibiotics.

Description: A 59-year-old male presented with chronic lower back pain, 45lbs unintentional weight loss, and malaise. Medical history included tongue cancer (treated with resection and radiation), nonischemic cardiomyopathy, and ICD placement 4 months prior. Examination revealed generalized wasting and pale membranes without cardiac murmur. Lab findings showed anemia, leukocytosis, elevated ESR, and CRP. Blood cultures confirmed pan-sensitive Streptococcus salivarius in two samples. TEE and TTE showed tricuspid valve thickening with a mobile echo density suggestive of subacute bacterial endocarditis (SBE) and two vegetations on the ICD lead near the tricuspid valve. The patient underwent ICD extraction and prolonged IV antibiotics. Follow-up blood cultures and inflammatory markers were unremarkable.

Discussion: Right-sided endocarditis (RSE) makes up 5-10% of endocarditis cases, often associated with intravenous drug use and cardiac devices. Staphylococcus aureus predominates (70% of RSE), while viridans streptococci account for 5-20%. Streptococcus salivarius, rare in infective endocarditis, constitutes about 2% of viridans streptococci cases and is often dismissed as a contaminant. Our case, with two positive blood cultures for Streptococcus salivarius and echocardiographic evidence of endocardial and ICD lead involvement, underscores the need to consider uncommon pathogens in infective endocarditis. This case highlights the importance of hardware removal in ICD infections and contributes to refining diagnostic and management strategies in clinical practice.