Evaluation of 16S rDNA Heart Tissue PCR as a Complement to Blood Cultures for the Routine Etiological Diagnosis of Infective Endocarditis

Abstract

Identification of the causative pathogen is required to optimize the effective therapy in infective endocarditis (IE). The aim of this study was to assess a 16S rDNA PCR to identify bacteria from heart valve tissues and to evaluate its usefulness as a complement to blood and removed valves cultures. A total of 266 patients diagnosed with IE from January 2015 to December 2019 were evaluated. Results between 16S rDNA PCR from heart valve tissues were compared with microbiological cultures. Blood cultures were positive in 83.5% of patients diagnosed with IE, while 39.6% and 71.8% of the evaluated heart valve samples were positive by culture and 16S rDNA PCR, respectively. For 32 (12%) patients, 16S rDNA tissue PCR provided valuable information supporting the results of blood cultures in the case of bacteria characteristic from the skin microbiota. Additionally, a microorganism was identified by using 16S rDNA PCR in 36% of blood culture-negative cases. The present study reveals that molecular diagnosis using 16S rDNA tissue PCR provides complementary information for the diagnosis of IE, and it should be recommended in surgical endocarditis, especially when blood cultures are negative.

Keywords: 16S rDNA PCR; blood culture; infective endocarditis; molecular diagnosis; valve heart culture.

Figure 1

Antimicrobial therapy duration before surgery and its relatedness with valve culture and 16S rDNA PCR results. Bars represent the median of days.

Figure 2

Microorganism detection by the different microbiological methods evaluated (blood culture, heart valve or vegetation culture, and/or 16S rDNA PCR).

Figure 3

Concordance between blood and heart valve culture and/or 16S rDNA valve PCR results.

Figure 4

Distribution of microorganisms with concordant results between blood and valve culture in comparison with 16S rDNA valve PCR.