Comparative genome analysis of an avirulent and two virulent strains of avian Pasteurella multocida reveals candidate genes involved in fitness and pathogenicity

Authors: JOHNSON, TIMOTHY - University Of Minnesota; ABRAHANTE, JUAN - University Of Minnesota; HUNTER, SAMUEL - University Of Idaho; Hauglund, Melissa; Tatum, Fred; MAHESWARAN, SAMUEL - University Of Minnesota; Briggs, Robert

Submitted to: BMC Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/6/2013
Publication Date: 5/14/2013
Publication URL: https://handle.nal.usda.gov/10113/57504
Citation: Johnson, T.J., Abrahante, J.E., Hunter, S.S., Hauglund, M.J., Tatum, F.M., Maheswaran, S.K., Briggs, R.E. 2013. Comparative genome analysis of an avirulent and two virulent strains of avian Pasteurella multocida reveals candidate genes involved in fitness and pathogenicity. Biomed Central (BMC) Genomics. 13:106.

Interpretive Summary: Fowl cholera, caused by the bacterium Pasteurella multocida (P. multocida), is a highly contagious disease of wild and domestic birds which often results in severe losses from sickness and death. Treatment of outbreaks with antibiotics, or prevention with current vaccines, is helpful but safety and efficacy issues remain. To facilitate better understanding of disease and development of improved control measures, we undertook a comparative analysis of the genomes of two disease-causing avian isolates of P. multocida and an isolate which does not cause disease. A number of differences were identified, including additional metabolic systems in the disease-causing isolates, which may play a role in bacterial fitness and disease development. The results facilitate focused studies on key genetic elements and systems which are likely involved in disease development and host adaptation, thereby leading to development of improved preventative measures.

Technical Abstract: Fowl cholera is a highly contagious systemic disease affecting wild and domestic birds, frequently resulting in high morbidity and mortality. The causative agent is Pasteurella multocida (P. multocida). The completed genome of P. multocida strain Pm70 has been available for over eleven years and has greatly facilitated subsequent genomic-based approaches towards understanding virulence, disease, and potential avenues of disease prevention. It has been speculated that the combination of additional P. multocida genome sequences and advances in our ability to genetically manipulate the organism will facilitate major advances in our understanding of disease pathogenesis, therefore allowing advances in development of disease control measures. To that end, we undertook comparative analyses of two highly virulent and an avirulent isolate of Pasteurella multocida. A number of genomic differences were identified which may shed light on the ability of highly virulent strains to cause disease in the avian host. Most of the identified differences were the presence of additional systems in virulent strains P1059 and/or X73 that appear to play a metabolic role. Such systems might enhance the fitness of these strains in the avian extraintestinal compartment, but without experimental evidence this is purely a speculative observation. This work does, however, underscore the need to utilize such genomic data towards targeted molecular approaches to better understand the role of horizontal gene transfer in the pathogenesis of this organism. It is evident, given the high degree of large sequence and single nucleotide polymorphisms in P. multocida, that focused studies need to be conducted to appreciate adaptation of these strains to their respective hosts.