Genome sequencing of Pasteurella multocida phage PMP1 elucidates a possible host resistance mechanism and suggests that it belongs to a new species.

Pasteurella multocida, especially capsular serotype A, is a zoonotic pathogen that is found mainly in livestock. While antibiotics are commonly used to treat bacterial infections, bacteriophage therapy has become an important alternative due to the issue of antibiotic resistance. Although four virulent P. multocida-infecting phages have been described, their interactions with their hosts have not been extensively studied. In this study, a novel virulent phage, PMP1, was isolated from a livestock waste treatment facility in Korea. This phage has a short, non-contractile tail with an isometric head and specifically lyses toxA-negative serotype A strains but can adsorb to toxA-positive strains. PMP1 has a genome of 38,049 bp in length with no genes related to lysogeny. Bioinformatic analysis and transmission electron microscopy suggest that a toxA-containing prophage could be involved in the restriction-modification system; however, the correlationof the presence of toxA with phage resistance was not clearly established. The structural proteins were identified for the first time in a P. multocida-infecting phage by LC-MS/MS analysis, and phylogenetic analysis revealed that PMP1 could be a member of new species in the genus Wuhanvirus. These findings suggest that this phage should be investigated further as a potential anti-P. multocida agent.