Enhanced metagenomic surveillance for bovine respiratory disease pathogens and antimicrobial resistance by...

Bovine respiratory disease (BRD) is the primary disease of cattle and is responsible for most of the antibiotic use in the beef industry, both for metaphylaxis and treatment. Infection prevention and targeted treatments would benefit from detecting and identifying bacterial pathogens and, ideally, assessing antibiotic sensitivity. Here, we report success refining targeted metagenomics by hybridization capture sequencing (CapSeq) to detect and genotype bacterial pathogens and genes for antibiotic resistance in BRD. We developed a novel multi-locus sequence typing (MLST) strategy to both enhance assay sensitivity and provide epidemiological data compatible with traditional typing assays. Phylogenetically informed panel design by ProbeTools coupled with hybridization capture enabled the sequencing of novel genotypes and elucidated coinfection by distinct strains of Mycoplasmopsis bovis. CapSeq was orders of magnitude more sensitive than classical metagenomics at a scale compatible with low-throughput DNA sequencing capacity in diagnostic laboratories. Iterative design and testing of longer typing loci confirmed improvements in locus detection through a strategy applicable to future target selection. CapSeq detected bacterial pathogens that evaded detection by traditional metagenomics, and it demonstrated greater range and sensitivity for antibiotic resistance gene detection.

Shotgun metagenomic sequencing for infectious disease diagnostics and surveillance benefits from simultaneous detection of multiple pathogens in a sample. Adding a hybridization probe capture step to the metagenomics workflow enriches targeted loci to improve the sensitivity of pathogen detection without compromising the ability to detect pathogen variants. Our custom probe panel enables multi-locus sequence typing of bovine respiratory disease agents as well as capture of antibiotic resistance genes, which improves the sensitivity of metagenomic testing and provides genotyping data compatible with traditional assays. This study demonstrates the utility of new design principles for probe panels; it also demonstrates how targeted metagenomics provides important new insights into co-infections and is equally useful for surveillance of environmental reservoirs of disease agents.