Corynebacterium striatum Bacteremia: Contamination or a Missed Cause of Infective Endocarditis? A Case Series and Proposed Clinical Algorithm

Corynebacterium striatum is often regarded as a contaminant, potentially delaying the diagnosis of infective endocarditis (IE). We evaluated the clinical characteristics of IE associated with Corynebacterium striatum bacteremia, highlighted diagnostic challenges, and proposed a diagnostic algorithm. Five patients with Corynebacterium striatum bacteremia who fulfilled the 2023 Duke-ISCVID criteria for IE were retrospectively analyzed. Clinical, echocardiographic, microbiological, treatment, and outcome data were reviewed. Native valve involvement predominated, and persistent bacteremia was the most consistent finding. Vegetations mainly involved the aortic and mitral valves. In one patient, the initial interpretation of Corynebacterium striatum as a contaminant delayed the diagnosis of IE. Severe complications were common, and three of the five patients died. Persistent or recurrent Corynebacterium striatum bacteremia should not be dismissed as contamination, particularly in patients with compatible clinical findings. Early echocardiographic evaluation should be considered when IE is suspected. We propose a diagnostic algorithm integrating microbiological and clinical findings to support the timely diagnosis of IE.