RT Journal Article SR Electronic T1 Blood culture negative endocarditis in the modern era of 16S rRNA sequencing JF Clinical Medicine JO Clin Med FD Royal College of Physicians SP 412 OP 416 DO 10.7861/clinmed.2019-0342 VO 20 IS 4 A1 Rebecca Godfrey A1 Sally Curtis A1 William HK Schilling A1 P Rachael James YR 2020 UL http://www.rcpjournals.org/content/20/4/412.abstract AB Blood culture negative endocarditis (BCNE) accounts for up to 20% of infective endocarditis. While the most common cause of BCNE remains the initiation of antibiotics prior to culture, intracellular organisms such as Coxiella and Bartonella spp account for a significant proportion of cases. Identifying the infecting organism remains important to ensure optimal antimicrobial treatment. However, these organisms can be difficult to diagnose. We outline a systematic approach to BCNE. Over half of patients with infective endocarditis now undergo early surgery and 16S ribosomal ribonucleic acid (rRNA) polymerase chain reaction (PCR) of excised tissue can be vitally important to secure a diagnosis. Molecular testing is likely to become a key tool in improving outcomes from BCNE and contribute to an improved understanding of the aetiology. We advocate modifying the Duke criteria to incorporate organisms identified on molecular testing, including 16S rRNA PCR, in particular from explanted tissue.