Pasteurella multocida in Veterinary Medicine Emerging Resistance, Vaccination Challenges, and Control Approaches

Pasteurella multocida is a Gram-negative bacterium of global veterinary importance, associated with a wide spectrum of diseases in livestock, poultry, rabbits, and companion animals. It can exist as a harmless commensal in the upper respiratory tract, but under favorable conditions acts as a potent pathogen, causing hemorrhagic septicemia in cattle and buffalo, progressive atrophic rhinitis in pigs, fowl cholera in poultry, and snuffles in rabbits. Pathogenesis is mediated by virulence factors including the polysaccharide capsule, lipopolysaccharides, adhesins, iron acquisition systems, biofilm formation, and the P. multocida toxin (PMT), which collectively promote colonization, immune evasion, and systemic infection. Advances in taxonomy and classification, from serotyping to multilocus sequence typing and whole-genome sequencing, have improved epidemiological understanding, though distinguishing virulent from commensal strains remains challenging. Antimicrobial resistance (AMR) is an emerging concern, particularly against tetracyclines and macrolides, threatening treatment efficacy in food-producing animals and increasing zoonotic risks. Vaccination remains central to control, with bacterins, toxoids, and autogenous vaccines widely used, though their cross-serotype protection is limited. Future perspectives highlight the need for next-generation vaccines, genomic surveillance, CRISPR-based diagnostics, and alternative therapies such as phage treatment. Integration of vaccination, antimicrobial stewardship, and biosecurity measures within a One Health framework will be essential to reduce disease burden, protect animal productivity, and safeguard public health.