The Role of Plasmids in Antibiotic Resistance in Pasteurella multocida Isolated from Various Sources

Abstract Antimicrobial resistance transmitting agents present in animal products and antibiotic use contributed to its occurrence and aggravation. The emergence of resistance toward several antibiotics groups among pathogenic bacteria is a growing global threat, and Pasteurella multocida is no exception in this case. The role of plasmids in creating different patterns of AMR on anyone is not hidden. One of the easiest ways to reduce antibiotic resistance is to stop the plasmid from replicating, dividing, and transferring by removing the plasmid. In this study, we investigated the role of P. multocida plasmids in the occurrence of antibiotic resistance. From different geographical regions of Iran, 131 definite isolates of P. multocida have been isolated from apparently healthy and sick animals. After plasmid DNA extraction, five isolates with evident plasmid were selected. Restriction mapping is used to determine the size of plasmids, so the restriction enzymes BglII, SspI, AluI were used to cleave the plasmids.Plasmid curing was performed, anddisk diffusion method was utilized to compare the antibiotic resistance pattern before and after plasmid curing. We found that the samples that contain plasmids and exhibited extensive antibiotic resistance did indeed lose their ability to resist antibiotics after their deletions and became sensitive to them. Indeed, this observation confirms the role and importance of plasmids in antimicrobial resistance in P. multocida. The study indicates that the ability of these isolates to retain plasmids has a significant effect on their ability to develop resistance to various antibiotics.