Infective Endocarditis with Un Unusual Pathogen in A Patient Under Teriflunomide Therapy

Infective endocarditis (IE) is an uncommon infection with high mortality, most often caused by Gram-positive cocci (80-90%) or by bacteria from the HACEK group (2-4%). Klebsiella aerogenes is rarely implicated in IE, accounting for less than 2% of non-HACEK Gram-negative endocarditis cases. We report a case of IE caused by Klebsiella aerogenes in a patient with multiple sclerosis (MS) undergoing treatment with teriflunomide. The patient presented in septic shock and was initially managed for presumed prostatitis. However, persistent neurological symptoms prompted further investigation, which revealed a large aortic valve vegetation. Urgent valve replacement was performed and cultures of the resected valve confirmed the final diagnosis of Klebsiella aerogenes endocarditis with embolic complications. The absence of traditional risk factors and the recent initiation of teriflunomide raise concerns about potential immunosuppressive effects and vulnerability to rare infections. This case highlights the importance of vigilance for opportunistic infections in patients treated with teriflunomide.