Usefulness of newer testing modalities for the accurate diagnosis of culture-negative endocarditis

A woman in her 80s with a history of congestive heart failure, atrial arrhythmia treated with atrioventricular nodal ablation and permanent pacemaker (PPM) placement, mitral valve disease status post-repair and colon cancer status post-treatment was admitted for further evaluation of severe dyspnea on exertion. Imaging revealed vegetation on both the prosthetic mitral valve and the PPM lead. Blood cultures were collected without growth, so a cell-free DNA Karius test was performed, which can detect over 1000 pathogens and has a sensitivity between 87% and 93%. Testing returned positive results for Streptococcus bovis subspecies pasteurianus. Given its association with colorectal cancer, abdominal imaging and an endoscopic biopsy were performed, showing recurrent colonic malignancy. The patient underwent a right colon resection prior to cardiac intervention. This report describes the clinical application of the novel cell-free DNA Karius test, which led to the diagnosis of recurrent colon cancer associated with S. pasteurianus endocarditis.