Familial Adenomatous Polyposis Manifesting as Lactococcus Endocarditis: A Case Report and Review of the Association of Lactococcus with Underlying Gastrointestinal Disease

A 45-year-old male with a prosthetic aortic valve presented to the hospital with several months of generalized malaise. On admission, he was noted to have anemia of unclear etiology and subsequently became febrile with multiple blood cultures growing Lactococcus garvieae. Inpatient workup was concerning for infectious endocarditis (IE) secondary to Lactococcus. The patient was discharged home with appropriate antimicrobial therapy; however, he was readmitted for persistent, symptomatic anemia and underwent colonoscopy, which revealed innumerable colonic polyps consistent with Familial Adenomatous Polyposis (FAP) that was later confirmed with genetic testing. Surveillance computed tomography (CT) imaging of the aortic repair later demonstrated valve dehiscence with surrounding fluid collection; he underwent redo surgery and was found to have destruction of the aortic annulus and a large pseudoaneurysm. Histopathology of the valve prosthesis confirmed IE. It is suspected that the patient developed Lactococcus IE from enteric translocation. Review of the literature provides several reports of Lactococcus infections in association with underlying gastrointestinal disease, including colorectal cancer. Given this association, we raise the question of whether the diagnosis of Lactococcus IE should evoke suspicion and encourage evaluation for gastrointestinal pathology, as occurs with Streptococcus bovis.