Enterococcus faecalis Endocarditis as a Diagnostic Clue to Occult Rectal Cancer: A Two-Case Series.

Enterococcus faecalis is an important cause of bacteremia and infective endocarditis, but the portal of entry often remains unclear. Enterococcal endocarditis is potentially fatal and predominantly affects older men in published cohorts. We describe two men, aged 69 and 40 years, who presented with E. faecalis infective endocarditis and gastrointestinal symptoms. The first patient was admitted with fever and ischemic stroke after three months of chronic diarrhea. Transthoracic echocardiography demonstrated a 12.5 × 5.6 mm mitral-valve vegetation. Pelvic magnetic resonance imaging and colonoscopy revealed a stenosing mid-rectal tumor, and biopsy confirmed invasive rectal adenocarcinoma staged as cT4aN2b. The second patient presented with fever, polyarthritis, and bloody diarrhea. Echocardiography showed a 13.2 × 6.5 mm aortic-valve vegetation, while computed tomography and colonoscopy revealed an ulcerated upper rectal mass with histopathological confirmation of mucinous adenocarcinoma. Both isolates were susceptible to vancomycin and gentamicin, and both patients received six weeks of intravenous vancomycin plus gentamicin. Follow-up blood cultures became negative in both cases. In Case 1, C-reactive protein decreased from 359 to 60 mg/L, transient renal dysfunction associated with glomerulonephritis resolved, and neurological recovery after ischemic stroke was partial. In Case 2, C-reactive protein normalized. Follow-up transthoracic echocardiography showed marked improvement after antimicrobial therapy. These cases support targeted colorectal evaluation in selected patients with E. faecalis endocarditis, particularly when gastrointestinal symptoms are present or no alternative portal of entry is identified.