Infective endocarditis caused by Lactobacillus rhamnosus in an immunocompetent patient without structural heart disease or invasive procedures: case report and literature review

Infective endocarditis caused by Lactobacillus rhamnosus is extremely rare, particularly in immunocompetent patients without structural heart disease or recent invasive procedures.

A 42-year-old immunocompetent man with no structural heart disease or recent interventions presented with fever and dyspnoea. Blood cultures grew L. rhamnosus. Transoesophageal echocardiography revealed a large vegetation on the aortic valve causing severe regurgitation, along with severe mitral regurgitation due to anterior leaflet perforation. The only identifiable risk factor was regular probiotic consumption. The patient underwent successful double valve replacement and completed 6 weeks of antibiotic therapy with favourable outcome.

A literature review identified 22 published cases of L. rhamnosus endocarditis. Most were associated with underlying valvular disease, invasive procedures, or probiotic use. This case highlights the need to consider Lactobacillus spp. as a potential pathogen, not merely a contaminant, in the appropriate clinical context, and calls for careful patient selection and monitoring when prescribing probiotics.