Bartonella quintana Endocarditis Identified Through Next-Generation Sequencing: A Case Report

Bartonella quintana endocarditis, which is traditionally associated with homelessness and lice exposure, poses a significant diagnostic challenge due to its fastidious nature and nonspecific presentation. Here, we report a case of blood culture–negative endocarditis caused by B. quintana in a 75-year-old man with no classic risk factors. The patient presented with recurrent heart failure, progressive anemia, thrombocytopenia and renal impairment. Blood and valve cultures demonstrated no growth after prolonged incubation. Diagnosis was ultimately achieved through a multimodal approach: serology suggested Bartonella infection and metagenomic next-generation sequencing of excised aortic valve tissue provided identification of B. quintana . The patient was successfully treated with doxycycline and rifampicin, leading to full clinical recovery. This case illustrates the evolving epidemiology of bartonellosis beyond classic risk factors and underscores the critical role of metagenomic next-generation sequencing as a decisive diagnostic tool in blood culture–negative endocarditis, enabling accurate identification of fastidious pathogens and facilitating targeted therapy.