title: Genome comparison of three serovar 5 pathogenic strains of Haemophilus parasuis: insights into an evolving swine pathogen.
abstract: Haemophilus parasuis is the causative agent of Glässer's disease, a systemic disorder characterized by polyarthritis, polyserositis and meningitis in pigs. Although it is well known that H. parasuis serovar 5 is the most prevalent serovar associated with the disease, the genetic differences among strains are only now being discovered. Genomes from two serovar 5 strains, SH0165 and 29755, are already available. Here, we present the draft genome of a third H. parasuis serovar 5 strain, the formal serovar 5 reference strain Nagasaki. An in silico genome subtractive analysis with full-length predicted genes of the three H. parasuis serovar 5 strains detected 95, 127 and 95 strain-specific genes (SSGs) for Nagasaki, SH0165 and 29755, respectively. We found that the genomic diversity within these three strains was high, in part because of a high number of mobile elements. Furthermore, a detailed analysis of large sequence polymorphisms (LSPs), encompassing regions ranging from 2 to 16 kb, revealed LSPs in virulence-related elements, such as a Toll-IL receptor, the AcrA multidrug efflux protein, an ATP-binding cassette (ABC) transporter, lipopolysaccharide-synthetizing enzymes and a tripartite ATP-independent periplasmic (TRAP) transporter. The whole-genome codon adaptation index (CAI) was also calculated and revealed values similar to other well-known bacterial pathogens. In addition, whole-genome SNP analysis indicated that nucleotide changes tended to be increased in membrane-related genes. This analysis provides further evidence that the genome of H. parasuis has been subjected to multiple lateral gene transfers (LGTs) and to fine-tuning of virulence factors, and has the potential for accelerated genome evolution.
authors.affiliation: Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Bello-Ortí
authors.affiliation: Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Barcelona, Spain.|Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
authors.forename: Virginia
authors.initials: V
authors.lastname: Aragon
authors.affiliation: Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Barcelona, Spain.|Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
authors.forename: Sonia
authors.initials: S
authors.lastname: Pina-Pedrero
authors.affiliation: Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Bensaid
mesh_terms: D000818:Animals; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D014644:Genetic Variation; D016680:Genome, Bacterial; D006192:Haemophilus Infections / Q000382:microbiology / Q000662:veterinary; D044137:Haemophilus parasuis / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA; D065288:Serogroup; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology
chemical_list: D004269:DNA, Bacterial