Abstract
BACKGROUND: The genus Bordetella comprises Gram-negative pathogens, notably B. pertussis, which causes whooping cough, underscoring the need to characterize antimicrobial resistance (AMR) within this group. However, reports of acquired antimicrobial resistance genes (ARGs) in non-B. pertussis Bordetella species remain scarce. METHODS: Non-B. pertussis Bordetella genomes were retrieved from NCBI, adapters trimmed and low-quality reads filtered, then assembled for analysis. ARGs were identified with Abricate, ResFinder, and BLAST, and their genomic contexts visualized using Easyfig. Core-genome SNP phylogeny and Bayesian clustering delineated lineages, and SNP-based thresholds quantified transmission. RESULTS: Across 746 genomes, 105 ARGs were identified in three non-B. pertussis species: B. bronchiseptica (96 ARGs), B. trematum (7 ARGs) and B. avium (2 ARGs). Ten distinct ARG types covering sulphonamide (sul1, sul2), tetracycline (tet(A), tet(G), tet(31)), aminoglycoside (aac(6')-IIa, aadA2, aph(3″)-Ib, aph(6)-Id) and β-lactam (blaOXA-2) resistance were observed. Core-genome SNP analysis of 238 B. bronchiseptica strains resolved three lineages, of which lineage 2 harboured the greatest diversity of multidrug-resistant isolates. Transmission-event quantification using SNP thresholds revealed frequent international and cross-host spread, notably human-dog/rabbit transfers and international dissemination between France and the United States. CONCLUSIONS: These findings underscore the importance of monitoring AMR in Bordetella species to anticipate and mitigate the spread of resistant strains.