A patient with vegetation on the mitral valve after a colonoscopy is most likely infected by which organism?

In the context of a patient developing vegetations on the mitral valve following a colonoscopy, the most likely organism responsible for the infection is Streptococcus gallolyticus, also known as S. bovis. This group of bacteria is associated with endocarditis, particularly in patients with underlying gastrointestinal pathology, such as colonic malignancies or polyps.

Streptococcus gallolyticus is notable for its association with colonic diseases and can lead to bacteremia and endocarditis following procedures like colonoscopy, where the integrity of the bowel may be compromised, allowing bacteria to enter the bloodstream. The presence of vegetation on the mitral valve in the setting of a recent colonoscopic procedure strongly suggests this organism as a viable cause.

While other organisms such as Staphylococcus aureus and Streptococcus viridans can also cause infective endocarditis, they are less likely to be specifically related to recent gastrointestinal procedures or colon pathology. Bartonella henselae is primarily associated with cat scratch fever and is less commonly linked to endocarditis in this context. Therefore, Streptococcus gallolyticus stands out as the likely organism due to its established clinical correlation with endocarditis in patients following procedures involving the gastrointestinal