Abstract
AimsUpon suspicion of infective endocarditis, the causative microorganism must be identified to optimize treatment. Blood cultures and culturing of removed valves are the mainstay of this diagnosis and should be complemented by growth-independent methods. We assessed the diagnostic benefit of examining removed endocarditis valves by broad-range bacterial PCR to detect causative bacteria in cases where culturing was not available, negative, or inconclusive because a skin commensal was detected, in patients from our clinical routine practice.Methods and resultsPatients from Heidelberg University Hospital with suspicion of endocarditis, followed by valve replacement and analysis by 16S rDNA PCR, between 2015 and 2018, were evaluated. 146 patients with definite infective endocarditis, confirmed by the valve macroscopics and/or histology, were included. Valve PCRs were compared to corresponding blood and valve culture results. Overall, valve PCR yielded an additional diagnostic benefit in 34 of 146 cases (23%) and was found to be more sensitive than valve culture. In 19 of 38 patients with both negative blood and valve cultures, valve PCR was the only method rendering a pathogen. In 23 patients with positive blood cultures detecting skin commensals, 4 patients showed discordant valve PCR results, detecting a more plausible pathogen, and in 11 of 23 cases, valve PCR confirmed commensals in blood culture as true pathogens. Only the remaining 8 patients had negative valve PCRs.ConclusionValve PCR was found to be a valuable diagnostic tool in surgical endocarditis cases with negative blood cultures or positive blood cultures of unknown significance.Trial registrationS-440/2017 on 28.08.2017 retrospectively registered.Graphic abstractSubdividing of all infective endocarditis patients in this study, showing that valve PCR yields valuable information for patients with skin commensals in blood cultures, which were either confirmed by the same detection in valve PCR or refuted by the detection of a different and typical pathogen in valve PCR. Additionally, benefit was determined in patients with negative or not available blood cultures and only positive detection in valve PCR. +: Positive; −: negative; n/a: not available results
Highlights
Infective endocarditis remains a clinical challenge, with often complicated courses, up to 50% of endocarditis patients needing surgical valve replacement, and an inhospital mortality of up to 30% [1,2,3]
Fournier et al describe specific PCR of the blood being positive for patients with Coxiella burnetii in 53% of cases, in which detection could be achieved by specific valve PCR, whereas 16S rDNA PCR of the blood only achieved a sensitivity of 14% [8]
Blood cultures have been taken according to guidelines [1], not all patients had at least three blood cultures taken or more than two positive blood cultures confirming a microorganism, because in some cases endocarditis was only suspected intraoperatively
Summary
Infective endocarditis remains a clinical challenge, with often complicated courses, up to 50% of endocarditis patients needing surgical valve replacement, and an inhospital mortality of up to 30% [1,2,3]. Identification of the causative microorganism (pathogen) and if possible, antibiotic drug susceptibility testing, are prerequisites for optimal antimicrobial therapy, and are currently done using blood cultures and culturing of removed valves. Should these remain negative, guidelines recommend alternative methods to achieve pathogen detection in as many patients as possible [1, 4, 5]. Fournier et al describe specific PCR of the blood being positive for patients with Coxiella burnetii in 53% of cases, in which detection could be achieved by specific valve PCR, whereas 16S rDNA (broad-range) PCR of the blood only achieved a sensitivity of 14% [8]. Specific PCR, is not suitable to screen for a spectrum of pathogens, and 16S rDNA PCR of the blood not sensitive enough so that many hospitals do not perform blood PCR in routine diagnostics
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
