ARS | Publication request: Comparative Genomic Hybridization Suggests a Unique Genetic Basis for Virulence of Bordetella hinzii

Submitted to: American Society for Microbiology General Meeting
Publication Type: Abstract Only
Publication Acceptance Date: February 17, 2009
Publication Date: May 17, 2009
Citation: Register, K.B., Nicholson, T.L. 2009. Comparative genomic hybridization suggests a unique genetic basis for virulence of Bordetella hinzii [abstract]. 109th American Society for Microbiology General Meeting. Poster No. Z-038.

Technical Abstract: Particular strains of Bordetella hinzii can induce mild to moderate respiratory disease in turkeys but potential virulence factors of this agent have not been identified, despite extensive characterization of virulence factors in several other Bordetella species. To elucidate the genetic basis for pathogenicity in B. hinzii, the genomes of 5 strains differing in their ability to colonize and cause disease in turkeys were compared individually with the genome of Bordetella bronchiseptica. Comparative genomic hybridization (CGH) was carried out using a microarray representing all known or predicted ORFs from B. bronchiseptica and DNA purified from B. hinzii. PCR and/or Southern blotting, and Western blotting using available antibodies specific for known Bordetella virulence proteins, were used to confirm CGH predictions. Results. Only 36% of the 5013 ORFs tested could be positively identified in one or more B. hinzii strains. Genes encoding most protein virulence factors of Bordetella, including bvgAS, fhaB, cyaA, brkA, dnt and most fimbrial structural genes, are either absent or highly divergent in all strains of B. hinzii evaluated. Proteins encoded by fhaB, cyaA, prn, and dnt are undetectable in B. hinzii by Western blotting. Also absent or highly divergent in all strains are genes encoding many structural or regulatory proteins that function in iron transport, nearly all genes of the wlb and wbm loci, required for LPS and O antigen biosynthesis, respectively, in B. bronchiseptica, and most genes known or purported to be involved in Type III secretion. Two linked ORFs encoding hypothetical proteins, likely within a single operon and found in a region of the B. bronchiseptica genome with an unusually low % GC, were also identified in all B. hinzii strains capable of tracheal colonization in poults but were not detectable in a strain unable to establish infection. Overall genetic relatedness between B. bronchiseptica and B. hinzii is low. The genetic basis for colonization of poults by B. hinzii and for strain-specific virulence appears to be unique with respect to other well-characterized Bordetella species.