Potential utility of metagenomic sequencing for improving etiologic diagnosis of infective endocarditis

Aim: To explore potential utility of metagenomic sequencing for improving etiologic diagnosis of infective endocarditis (IE) caused by fastidious bacteria. Materials & methods: Plasma and heart valves of two patients, who were diagnosed with IE caused by Bartonella quintana and Propionibacterium species, were sequenced by using Illumina MiSeq and Nanopore MinION. Results: For patient 1, B. quintana was detected in the plasma pool collected 4 days before valvular replacement surgery. For patient 2, Propionibacterium sp. oral taxon 193 was detected in the plasma sample collected on hospital day 1. Nearly complete bacterial genomes (>98%) were retrieved from resected heart valves of both patients, enabling detection of antibiotic resistance-associated features. Real-time sequencing of heart valves identified both pathogens within the first 16 min of sequencing runs. Conclusion: Metagenomic sequencing may be a helpful supplement to IE diagnostic workflow, especially when conventional tests fail to yield a diagnosis.