Comprehensive genetic analysis of an avian isolate of Pasteurella multocida

Pasteurella multocida is the etiologic agent of a variety of economically significant diseases including fowl cholera in birds, hemorrhagic septicemia in cattle, atrophic rhinitis in swine, and the most common source of infection in man due to dog and cat bites. The global distribution, severity of diseases caused, and the wide variety of livestock affected by P. multocida account for considerable economic losses due to this pathogen worldwide. Current research has provided substantial information regarding P. multocida growth requirements, colony appearance, and biochemical characteristics, however, little is known regarding the molecular basis for P. multocida's pathogenicity. In order to address these issues, we tested the following hypotheses: (i) the genome sequence of P. multocida will aid in the identification of putative genes involved in P. multocida colonization and pathogenicity; and (ii) P. multocida contains sets of metabolic/virulence gene networks that respond to stress.; In order to create a foundation for future studies for a better molecular understanding of P. multocida, the genome of an avian isolate of P. multocida was sequenced. This allowed for identification of all potential genes, intergenic regions, and chromosome organization. Of importance were the identification of putative genes unique to P. multocida, a large set of hypothetical genes with no known function, as well as those putative genes involved in cellular metabolism, transport, and virulence.; In order to elucidate P. multocida's response to extracellular stress, DNA microarray technology was applied to determine the genome-wide transcriptional profiles of P. multocida in response to several environmental stressors: heat shock, acid stress, oxidative stress, and sodium stress. The global patterns of gene expression in P. multocida in response to individual and multiple stressors (the general stress response) were analyzed, and provided insight into the mechanisms by which P. multocida can adapt to stress.