The complete genome sequence and analysis of the human pathogen Arcobacter butzleri.

Background: The human pathogen Arcobacter butzleri is a member of the epsilon subdivision of the Proteobacteria and a close taxonomic relative of other established pathogens, such as Campylobacter jejuni and Helicobacter pylori. Here we present the complete genome sequence of the human clinical isolate, A. butzleri strain RM4018. Results: Arcobacter butzleri is a member of the Campylobacteraceae, but the majority of its proteome is most similar to those of Thiomicrospira denitrificans and Wolinella succinogenes, both members of the Helicobacteraceae. In addition, many of the genes and pathways described here, e.g. those involved in signal transduction and sulfur metabolism, have been identified previously within the epsilon subdivision only in T. denitrificans and/or W. succinogenes, or are unique to the subdivision. The analyses indicated also that a large proportion of the A. butzleri genome is devoted to growth and survival under diverse environmental conditions, with a large number of respiration-associated proteins, signal transduction and chemotaxis proteins and proteins involved in DNA repair and adaptation. To investigate the genomic diversity of A. butzleri strains, we constructed an A. butzleri DNA microarray comprising 2238 genes from strain RM4018. Comparative genomic indexing analysis of 12 additional A. butzleri strains identified both the core genes of A. butzleri and intraspecies hypervariable regions, where < 70% of the genes were present in at least two strains. Conclusion: The presence of environmentally-associated pathways and loci, as well as genes associated with virulence indicates that this free-living, water-borne organism A. butzleri can be classified rightfully as an emerging pathogen. Keywords: comparative genomic hybridization Overall design: The genomic diversity of 13 A. butzleri strains from a both human and animals was examined by microarray-based comparative genomic indexing (CGI) analysis. The CGI analysis allowed the assessment of CDS content for each A. butzleri strain relative to the A. butzleri DNA microarray, which comprises 2238 CDS from strain RM4018. Genomic DNA from strain RM4018 was used as a reference DNA and competitively hybridized with genomic DNA from each of the A. butzleri strains. We used the GENCOM software to assign the CDS as present, absent or multicopy for each A. butzleri strain.