Differences between predicted outer membrane proteins of Pasteurella multocida, Histophilus somni, and genotype 1 and 2 Mannheimia haemolytica strains isolated from cattle

Authors: Wynn, Emily; Clawson, Michael - Mike

Submitted to: Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/27/2021
Publication Date: 8/4/2021
Citation: Wynn, E.L., Clawson, M.L. 2021. Differences between predicted outer membrane proteins of Pasteurella multocida, Histophilus somni, and genotype 1 and 2 Mannheimia haemolytica strains isolated from cattle. Genome. https://doi.org/10.1139/gen-2021-0038.
DOI: https://doi.org/10.1139/gen-2021-0038

Interpretive Summary: Bovine respiratory disease (BRD) affects cattle throughout the world and is a serious animal welfare and economic problem. BRD is the biggest killer of newly weaned cattle in the United States, with costs from treatments, morbidities, and overall productivity exceeding one billion dollars annually. There are a number of different viral and bacterial pathogens that cause BRD in combination with environmental factors and the genetic composition of individual animals. Antibiotics are routinely used for BRD treatment, which increases selection pressures for bacteria with antimicrobial resistance (AMR) in cattle. Histophilus somni, Mannheimia haemolytica, and Pasteurella multocida are three major bacterial pathogens that cause BRD and are known to harbor AMR genes. In this study, genomes of all three bacteria species were analyzed for outer membrane proteins (OMPs). These are proteins that are embedded in the outer membrane of the bacteria and protrude outward into the external milieu. Thus, OMPs can be accessible to host immune factors including antibodies. A large variety of OMPs were identified, including those that were present in all three bacterial species as well as some found in only one or two of them. This study was relatively small and should be followed with a larger one involving more bacterial genomes. However, some of the OMPs identified here are known to stimulate a favorable host immune response. Thus, a select set of them could be used to develop interventions that effectively target all three pathogens, and consequently reduce BRD incidence and subsequent needs for antibiotic treatments in cattle.

Technical Abstract: Common bacterial causes of bovine respiratory disease (BRD) include Histophilus somni, Mannheimia haemolytica, and Pasteurella multocida. Within M. haemolytica, two major genotypes are commonly found in cattle (1 and 2), however, genotype 2 strains are isolated from diseased lungs much more frequently than genotype 1 strains. Outer membrane proteins (OMPs) of H. somni, P. multocida, and genotype 2 M. haemolytica may be important factors for acquired host immunity. Predicted OMP differences between genotype 1 and 2 M. haemolytica have been previously identified. In this study, we expanded that focus to include bovine-isolated strain genomes representing all three species and the two M. haemolytica genotypes. Reported here are the core genomes unique to each of them, core genomes shared between some or all combinations of the three species and two M. haemolytica genotypes, and predicted OMPs within these core genomes. The OMPs identified in this study are potential candidates for further study and the development of interventions against BRD.