Global genomic epidemiology and antimicrobial resistance dynamics of Pasteurella multocida

Abstract Pasteurella multocida ( P. multocida ) is a crucial zoonotic pathogen, and its severe prevalence of antimicrobial resistance has attracted widespread attention in recent years. A global genomic analysis of 1,875 P. multocida isolates collected from 35 countries between 2011 and 2026 was performed to characterize antimicrobial resistance gene (ARG) carriage, population structure, and international transmission drivers. Overall, 23.68% (444/1,875) of isolates carried ARGs, conferring resistance to 12 distinct antibiotic classes. The most prevalent ARGs were aph(3’’)-Ib_2 , aph(6)-Id_1 , sul2_2 , tet (H)_3. Germany exhibited the highest ARG prevalence (89.30%), whereas the US, despite contributing the largest number of isolates, showed a markedly lower prevalence (17.43%). Temporal analysis revealed an increasing trend of ARG-positive reports over the study period, peaking in 2025. Phylogenetic analysis partitioned ARG-positive isolates into three major clades: Clade I (predominantly ST1 and ST3 from Germany and the USA) carried the highest ARG counts, while Clade II (mostly unknown sequence types from China) carried the fewest. Transmission network analysis applying a ≤ 50 SNP threshold identified frequent international dissemination events, particularly between Germany and North America/Europe. Notably, integrative and conjugative elements (ICEs) were detected in 33 isolates (36 ICEs total), 22 of which carried ARGs; the most common combination was aph(3’’)-Ib_2 / aph(3’)-Ia_3 / aph(6)-Id_1 / sul2_2 . Insertion sequence (IS) abundance was positively correlated with ARG carriage, whereas plasmid numbers showed a significant negative correlation. In conclusion, the results suggest that further efforts should be made to strengthen the epidemiological surveillance and prevention and control of antimicrobial resistance prevalence in P. multocida .