Added diagnostic value and impact on antimicrobial therapy of 16S rRNA PCR and amplicon sequencing on resected heart valves in infective endocarditis: a prospective cohort study.

OBJECTIVES: For adequate management and therapy of infective endocarditis (IE), identification of the causative pathogen is crucial but molecular testing results are not currently included in diagnostic criteria. The added diagnostic value and impact on antimicrobial therapy of 16S rRNA PCR and amplicon sequencing (16S rRNA PCR) performed on excised heart valves from patients with IE was evaluated alongside the effect of pre-operative antibiotics on the performance of blood culture (BC), valve culture (VC) and 16S rRNA PCR.

METHODS: All patients undergoing valve surgery for definite or possible IE, according to modified Duke Criteria, were prospectively included from July 2013 up to and including June 2016.

RESULTS: In all, 127 patients were included. Sensitivity for detecting the causative micro-organism in 120 post-operative definite IE patients was 26% for VC and 87% for BC and 16S rRNA PCR. 16S rRNA PCR, VC and BC were equally sensitive for different valve types and causative pathogens. In 27 (21%) definite IE patients, 16S rRNA PCR clarified discrepant culture results or was the only method identifying the causative pathogen. In 12 (10%) post-operative definite IE cases, molecular testing results influenced antimicrobial therapy.

CONCLUSIONS: The very good performance characteristics, added diagnostic value and impact on antimicrobial therapy of molecular testing of heart valves should support the incorporation of molecular testing in diagnostic criteria and guidelines for IE.