Global Genomic Analysis of Brucella spp. Reveals Antimicrobial Resistance, Virulence, and Mobile Genetic Element Profiles from a One Health Perspective

Abstract

Brucellosis is a globally distributed zoonotic disease that poses a severe threat to human and animal health. However, the population structure, evolutionary dynamics, and antimicrobial resistance (AMR)-associated genomic characteristics of Brucella spp. across hosts, regions, and time periods remain insufficiently characterized. A total of 1760 publicly available Brucella spp. genomes were retrieved. After metadata screening, 701 genomes lacking required metadata were excluded, and 1059 genomes were retained for downstream analyses. Analyses included annotation of antimicrobial resistance genes (ARGs), virulence factors (VFs), and mobile genetic elements (MGEs), together with multilocus sequence typing (MLST), pan-genome analysis, and phylogenomic reconstruction. MLST assigned 836 genomes to 49 sequence types, whereas 223 remained unclassified. Environmental isolates showed relatively higher ARG annotation abundance in the analyzed dataset. Peptide resistance-associated annotations predominated (91.6%), largely due to Bsui_mprF and bacA, followed by β-lactam (4.3%) and aminoglycoside (2.6%), reflecting resistance-associated genomic annotations rather than phenotypically confirmed AMR. Several ARGs occurred in MGE-associated genomic contexts, suggesting potential mobility. VF profiles were broadly conserved overall, while selected determinants varied among species, geographic regions, and sources. Phylogenomic analysis revealed close relationships among isolates from different hosts, with ST8 and ST11 representing predominant lineages. These findings support integrated genomic surveillance across human, animal, and environmental sources.