The utility of 16S RRNA gene PCR and sequencing in endocarditis: an 8 year review

Abstract

<h3>Background</h3> Up to 31% of patients with infective endocarditis (IE) have negative blood cultures, often due to prior antibiotic therapy or fastidious organisms. In surgically treated patients, 16S rDNA PCR applied to excised heart valve tissue is a useful tool for determining the bacterial aetiology of endocarditis. We sought to evaluate the clinical utility of this technique by reviewing data over the last 8 years. <h3>Methods</h3> Patients who underwent cardiac surgery and had valve specimens submitted for 16S rDNA PCR at Auckland City Hospital between January 2004 and July 2011 were retrospectively reviewed. Clinical records and laboratory databases were used to classify each patient according to modified Duke criteria and to record whether PCR determined the bacterial aetiology and impacted on antibiotic management. <h3>Results</h3> PCR was applied to 50 excised valve specimens from 40 patients. Twenty-four patients (60%) were PCR positive. For 13 of 40 patients (33%), the aetiology of IE was determined by valve PCR alone. In seven patients, this PCR result lead to a modification in antibiotic therapy to target the pathogen identified. <h3>Conclusions</h3> 16s rDNA PCR of excised valves from patients with suspected IE has had substantial clinical utility in our setting and should be considered for patients with blood culture negative endocarditis whose valves are culture negative.