A rare case of native mitral valve infective endocarditis by Lactobacillus jensenii in a healthy young patient

Abstract

Lactobacillus jensenii, a Gram-positive facultative anaerobic bacterium, is part of the normal vaginal microbiome and is occasionally found in fermented foods and probiotics. It is a rare cause of infections, with infective endocarditis (IE) being exceedingly uncommon. We report a case of IE caused by Lactobacillus jensenii in a previously healthy 15-year-old female who presented with progressive dyspnea, fever, and severe mitral regurgitation. Echocardiography revealed a vegetative mass on the anterior mitral leaflet. Blood cultures identified L. jensenii using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight mass spectrometry. Surgical repair confirmed myxomatous degeneration and chronic inflammation of the mitral valve. The patient fully recovered after surgery and a 6-week antibiotic course. A review of 12 reported cases of L. jensenii IE, including our case, shows a predominance in immunocompetent females, possibly due to its role as a vaginal commensal. Most cases involved native valves with underlying pathology facilitating bacterial colonization. An empirical regimen with ampicillin and gentamicin is effective against L. jensenii. A treatment duration of 4-6 weeks is sufficient, with favorable outcomes.