Comparison of the Genome Sequence of the Poultry PathogenBordetella aviumwith Those ofB. bronchiseptica,B. pertussis, andB. parapertussisReveals Extensive Diversity in Surface Structures Associated with Host Interaction

Abstract

Bordetella avium is a pathogen of poultry and is phylogenetically distinct from Bordetella bronchiseptica, Bordetella pertussis, and Bordetella parapertussis, which are other species in the Bordetella genus that infect mammals. In order to understand the evolutionary relatedness of Bordetella species and further the understanding of pathogenesis, we obtained the complete genome sequence of B. avium strain 197N, a pathogenic strain that has been extensively studied. With 3,732,255 base pairs of DNA and 3,417 predicted coding sequences, it has the smallest genome and gene complement of the sequenced bordetellae. In this study, the presence or absence of previously reported virulence factors from B. avium was confirmed, and the genetic bases for growth characteristics were elucidated. Over 1,100 genes present in B. avium but not in B. bronchiseptica were identified, and most were predicted to encode surface or secreted proteins that are likely to define an organism adapted to the avian rather than the mammalian respiratory tracts. These include genes coding for the synthesis of a polysaccharide capsule, hemagglutinins, a type I secretion system adjacent to two very large genes for secreted proteins, and unique genes for both lipopolysaccharide and fimbrial biogenesis. Three apparently complete prophages are also present. The BvgAS virulence regulatory system appears to have polymorphisms at a poly(C) tract that is involved in phase variation in other bordetellae. A number of putative iron-regulated outer membrane proteins were predicted from the sequence, and this regulation was confirmed experimentally for five of these.The genus Bordetella comprises eight species: B. pertussis, B. parapertussis, B. bronchiseptica, B. avium, B. hinzii, B. holmesii, B. trematum, and B. petrii. The genus is classified as a member of the beta-proteobacteria. Bordetellae are closely related to the genera Achromobacter and Alcaligenes, which include mostly environmental bacteria with some opportunistic pathogens (reviewed in reference 112). A phylogenetic analysis based on 16S rRNA genes places Alcaligenes as the most ancient, with Achromobacter and Bordetella deriving more recently from a single node and B. petrii and B. avium being most distantly related to all other Bordetella species (112). The very close phylogenetic relationship among B. pertussis, B. parapertussis, and B. bronchiseptica has been well established (110), and it is generally accepted that B. pertussis and B. parapertussis were differentiated from B. bronchiseptica by substantial gene loss (29, 71), diverging as much as 3.5 million years ago (30). B. pertussis, B. parapertussis, and B. bronchiseptica colonize the respiratory tracts of mammals (reviewed in reference 25), but their host ranges and the severity of the diseases they cause differ. B. pertussis is restricted to the human host and is the etiological agent of an acute respiratory disease known as pertussis or whooping cough. B. parapertussis is divided into two phylogenetically distinct subspecies/popula...

Isolation ofBordetella aviumand NovelBordetellaStrain from Patients with Respiratory Disease

“…A previous report demonstrated that cultures of B. avium were consistently resistant to penicillin and cefuroxime but susceptible to mezlocillin, piperacillin, gentamicin, amikacin, and cefoperazone (6). Although B. avium has been shown to share several virulence factors with B. pertussis, B. parapertussis, and B. bronchiseptica, it does not carry genes that encode pertussis toxin or adenylate cyclase toxin (7). B. avium and B. avium-like organisms have yet-unidentifi ed virulence factors, which may contribute to their ability to cross over from an animal host to an opportunistic human pathogen.…”

A Polysaccharide Lyase from Stenotrophomonas maltophilia with a Unique, pH-regulated Substrate Specificity

“…The amino acid sequences of PL-5 lyases from Achromobacter xylosoxidans (Swiss-Prot F7SXN4), Bordetella avium (34), Cobetia marina (Swiss-Prot Q9ZNB7), P. aeruginosa (35), and Spingomonas sp. A1 (PDB 1QAZ) (36) were aligned with Smlt1473 using COBALT (37).…”

Virulence and molecular aspects of Bordetella avium isolated from cockatiel chicks (Nymphicus hollandicus) in Brazil

“…Comparing the genomic sequence of B. avium and other Bordetella species, Sebaihia et al (2006) described that the gene encoding the dermonecrotic toxin (dnt) is present in the B. avium genome but at a different location than in those of the previously sequenced species. The morphological changes observed in this study were very similar to the changes observed by Ohnishi et al (2008) who evaluated B. pertussis strains, yet new in vitro and in vivo studies are required to characterize the action of the toxins produced by the B. avium strains isolated from cockatiels.…”