Diagnostic Yield and Incremental Value of 16S rRNA Gene PCR and Sequencing on Excised Heart-Valve Tissue in Infective Endocarditis: A Systematic Review and Meta-Analysis

Background/Objectives: Broad-range bacterial 16S rRNA gene PCR followed by sequencing may improve the etiological diagnosis of infective endocarditis (IE), particularly when conventional cultures are negative. This systematic review and meta-analysis evaluated the overall molecular detection yield and incremental value of valve-tissue 16S molecular testing in surgically managed IE. Methods: PubMed/MEDLINE, Scopus, Web of Science Core Collection, and Europe PMC were searched for Open Access studies published from 2016 to 2026. Eligible studies evaluated broad-range bacterial 16S PCR with sequence-based identification on excised native or prosthetic heart-valve tissue. Random-effects generalized linear mixed models were used to pool overall diagnostic yield, strict blood-culture-negative IE (BCNE) yield, and strict incremental etiologic yield beyond conventional microbiology. Diagnostic accuracy was summarized descriptively when complete 2 × 2 data were available. Results: Eight studies comprising 925 patients, surgical cases, or IE episodes contributed to the primary analysis, with 704 study-reported molecular-positive results. The pooled diagnostic yield was 75.9% (95% CI, 68.7–82.0%), with substantial heterogeneity (I2 = 81.8%) and a 95% prediction interval of 49.2–91.2%. In strict BCNE, the pooled yield was 53.7% (95% CI, 41.2–65.8%). The strict incremental etiologic yield was 8.8% (95% CI, 6.1–12.5%). Sensitivity analyses yielded similar estimates. Conclusions: Valve-tissue 16S PCR/sequencing can provide valuable etiological information, particularly in BCNE. However, the substantial between-study heterogeneity and wide prediction interval indicate that its expected molecular detection yield varies considerably across clinical settings and is influenced by patient selection, local diagnostic algorithms, laboratory methods, and reference standards.