Journal of Clinical Microbiology vol:Ahead of print
Identification of the causative pathogen of infective endocarditis is crucial for adequate management and therapy. A broad range PCR/electrospray ionization mass spectrometry (PCR/ESI-MS) technique was compared with broad-spectrum 16S rRNA PCR and amplicon sequencing (16S rRNA PCR) for detecting bacterial pathogens in 40 heart valves obtained from 34 definite infective endocarditis patients according to the modified Duke Criteria and six non-endocarditis patients. Concordance between both molecular techniques was 98% for being positive or negative, 97% for concordant identification up to genus level and 77% for concordant identification up to species level. Sensitivity for detecting the causative pathogen (up to genus level) in excised heart valves was 88% for 16S rRNA PCR and 85% for PCR/ESI-MS, specificity was 83% for both methods. Both molecular techniques were significantly more sensitive than valve culture (18%) and accurately identified bacteria in excised heart valves. In eight patients with culture negative IE following results were obtained: concordant detection of Coxiella burnetii (n=2), Streptococcus gallolyticus (n=1), Propionobacterium acnes (n=1) and viridans group streptococci (n=1) by both molecular tests, detection of P. acnes by PCR/ESI-MS whereas 16S rRNA PCR was negative (n=1) and a false negative result by both molecular techniques (n=2). In one case of IE caused by viridans streptococci, PCR/ESI-MS was positive for Enterococcus spp.. Advantages of PCR/ESI-MS compared to 16S rRNA PCR are its automated workflow and shorter turn-around-times.