ARS | Publication request: Exploring the diversity of Arcobacter spp. in cattle in the UK using MLST and whole genome sequencing

Submitted to: PLoS One
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 20, 2012
Publication Date: February 6, 2013
Citation: Merga, J.Y., Williams, N.J., Miller, W.G., Leatherbarrow, A.J., Bennett, M., Hall, N., Ashelford, K.E., Winstanley, C. 2013. Exploring the diversity of Arcobacter spp. in cattle in the UK using MLST and whole genome sequencing. PLoS One. 8(2):e55240. doi:10.1371/journal.pone.0055240.

Interpretive Summary: Arcobacter butzleri is an emerging human foodborne pathogen, causing some of the same clinical symptoms as other related foodborne pathogens, such as Campylobacter jejuni. The genome sequence of a human clinical isolate of Arcobacter butzleri was completed recently. In that study, several different clinical and food-related strains of A. butzleri were examined and a surprising level of diversity was identified. To further explore this diversity, A. butzleri was isolated from beef and dairy cow fecal samples on farms in the UK. Typing of these strains revealed that the population present among the beef and dairy cows was quite diverse, as expected. One of these cattle isolates was selected for genomic DNA sequencing. Comparison of the two A. butzleri chromosomal DNA sequences revealed a number of differences, particularly in genes responsible for sensing and acting upon changes in the environment. Additional differences included potentially key additions or deletions of metabolic pathways that could influence growth in a particular host animal. Additional research, however, would be necessary to determine conclusively if these genetic differences are related directly to colonization of cattle.

Technical Abstract: Arcobacter butzleri is considered to be an emerging human foodborne pathogen. The completion of an A. butzleri genome sequence along with microarray analysis of 13 isolates in 2007 revealed a surprising amount of diversity amongst A. butzleri isolates from humans, animals and food. In order to further investigate Arcobacter diversity, 792 faecal samples were collected from cattle on beef and dairy farms in the North West of England. Arcobacter was isolated from 42.5% of the samples and the diversity of the isolates was investigated using multi-locus sequence typing. An A. butzleri whole genome sequence, obtained by 454 shotgun sequencing of an isolate from a clinically-healthy dairy cow, showed a number of differences when compared to the genome of a human-derived A. butzleri isolate, particularly in environmental sensing and survival-related systems. PCR-based prevalence assays for variable genes suggested some evidence for source-related distributions. We also found evidence for phenotypic differences relating to growth capabilities between our representative human and cattle isolates. Our genotypic and phenotypic observations suggest that some level of niche adaptation has occurred in A. butzleri.