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

Abstract

BackgroundPasteurella multocida is the etiologic agent of fowl cholera, a highly contagious and severe disease of poultry causing significant mortality and morbidity throughout the world. All types of poultry are susceptible to fowl cholera. Turkeys are most susceptible to the peracute/acute forms of the disease while chickens are most susceptible to the acute and chronic forms of the disease. The whole genome of the Pm70 strain of P. multocida was sequenced and annotated in 2001. The Pm70 strain is not virulent to chickens and turkeys. In contrast, strains X73 and P1059 are highly virulent to turkeys, chickens, and other poultry species. In this study, we sequenced the genomes of P. multocida strains X73 and P1059 and undertook a detailed comparative genome analysis with the avirulent Pm70 strain. The goal of this study was to identify candidate genes in the virulent strains that may be involved in pathogenicity of fowl cholera disease.ResultsComparison of virulent versus avirulent avian P. multocida genomes revealed 336 unique genes among the P1059 and/or X73 genomes compared to strain Pm70. Genes of interest within this subset included those encoding an L-fucose transport and utilization system, several novel sugar transport systems, and several novel hemagglutinins including one designated PfhB4. Additionally, substantial amino acid variation was observed in many core outer membrane proteins and single nucleotide polymorphism analysis confirmed a higher dN/dS ratio within proteins localized to the outer membrane.ConclusionsComparative analyses of highly virulent versus avirulent avian P. multocida identified a number of genomic differences that may shed light on the ability of highly virulent strains to cause disease in the avian host, including those that could be associated with enhanced virulence or fitness.

OmpA protein sequence-based typing and virulence-associated gene profiles of Pasteurella multocida isolates associated with bovine haemorrhagic septicaemia and porcine pneumonic pasteurellosis in Thailand

“…The ompA genes displayed a dN/dS ratio of less than one, indicating that these genes are under purifying or stabilising selection that does not allow the genes to change drastically over time, consistent with the calculation by Johnson et al [ 11 ]. The selection pressures on different regions of the ompA genes of P. multocida were also observed to be unequal based on the fact that the multiple aligned OmpA sequences showed the presence of limited variable regions, a characteristic that could have caused the observed clustering in the protein phylogenetic tree.…”

Genome-Wide Analyses Reveal Genes Subject to Positive Selection in Pasteurella multocida

“…Analyses of SNPs in three P. multocida genomes has indicated a higher d N / d S ratio is prone to occur on the genes encoding outer membrane proteins interacted with the host immune system (Johnson et al, 2013). The massive accumulation of genomic sequence data enables researchers to apply more robust d N / d S -based methods to trace evolutionary trajectories on the protein-coding genes under positive Darwinian selection exerted by the host immune system.…”

Ocorrência de genes tad associados à formação de biofilme em isolados de Pasteurella multocida de pulmões de suínos com pneumonia

“…São descritos também, os genes exbB/tonBe hgbA envolvidos no sequestro de ferro, os genes codificadores da neuraminidase (nanB e nanH), fímbria do tipo IV e proteínas de membrana externa (OMP e Oma87) (Ruffolo & Alder 1996, Bethe et al 2009). Além de dez genes associados à utilização de L-fucose, responsável pelo metabolismo de carboidratos, fundamentais aos processos bacterianos para aquisição de energia em ambiente de baixa disponibilidade de nutrientes, como o trato respiratório (Johnson et al 2013).…”