Culture Clash: Dual-Pathogen Endocarditis and the Metagenomic Next-Generation Sequencing Studies We Need

We read with great interest Khalil et al.'s article on metagenomic next generation sequencing (mNGS) to diagnose culture-negative cardiovascular infections.[1] We commend the authors for articulating the importance of non-invasive, hypothesis-free testing and wholeheartedly agree that mNGS positivity for Bartonella species and Coxiella burnetii be included in the update of the modified Duke criteria.[2] We wish to highlight remaining knowledge gaps and the future studies that may address them.While the authors appropriately acknowledge the limitations of conventional microbiologic testing, they do not fully address why invasive procedures are often necessary to diagnose endocarditis caused by culture-negative bacteria: the low sensitivity of PCR performed on peripheral blood.Although PCR remains a cornerstone for diagnosing Bartonella and Coxiella, --------