De novo assembly of Campylobacter fetus subspecies and biovars genomes reveal unique features in pathogenecity islands

Campylobacter fetus subsp. fetus (CFF) and C. fetus subsp. venerealis (CFV) both cause disease in livestock but each subspecies generally occupy different specific host niches. CFF is normally found in the gut while CFV in the genital tract of ruminants. CFV infections can cause abortion and infertility in cattle, while CFF is unlike to result is such severe outcomes. To understand the molecular basis for such differences we sequenced the genomes of two CFV biovars (venerialis and intermedius) using Illumina/GA technology. Our current draft assemblies suggest a similar genome size for both CFVv and CFVi biovar genomes (~1.94Mbp) that are longer than the 1.77 Mbp genome of the reference CFF ATCC 19438 genome.  As compared to the CFF genome 99kb and 94kb unique regions were found in the CFVv and CFVi genomes. These sequences have been utilized to design biovar specific assays for diagnosis of field samples. The presence of a pathogenecity island (PAI) is known to be associated with the virulence of these strains, our analysis shows that are unique features in the CFVv PAI as well as significant sequence divergence in the CFVi PAI. We also present results towards the elucidation of the molecular basis of the glycine intolerance of CFV strains that is a feature used in current diagnosis labs to differentiate between CFF and CFF infections.