16S rRNA sequencing as a diagnostic tool in the identification of culture-negative endocarditis in surgically treated patients.

Background And Aim Of The Study: Infective endocarditis (IE) is a worldwide problem, and at least one-third of cases are culture-negative despite the use of appropriate laboratory techniques.

Methods: A broad-range polymerase chain reaction (PCR) amplification was performed of the 16S rRNA gene, followed by single-strand sequencing for 26 surgically removed heart valves from patients with culture-negative endocarditis who had undergone valve repair or replacement.

Results: Two of the 26 patients were PCR-positive, and sequencing of the amplicon identified the etiological agent.

Usefulness of 16S rDNA sequencing for the diagnosis of infective endocarditis caused by Corynebacterium diphtheriae.

We report a rare case of infective endocarditis caused by Corynebacterium diphtheriae in an 8-year-old boy, 2 years after a right ventricular outflow tract reconstruction with a bovine Contegra valved conduit. The patient recovered well after an RV-PA conduit enblock explantation and replacement with an aortic homograft with antibiotic treatment. All bacteriological cultures of excised tissue and blood were negative.