Genotypic variation among Arcobacter isolates from a farrow-to-finish swine facility

Arcobacter spp. were isolated from nursing sows and developing pigs on three farms of a farrow-to-finish swine operation and market-age pigs at slaughter. Isolates were identified by polymerase chain reaction and genotypic fragment patterns were examined by pulsed-field gel electrophoresis (PFGE). Incidences of Arcobacter-positive samples increased progressively as the pigs aged, resulting in all of the pens at the end of the growth cycle in the finishing barn containing Arcobacter-positive feces. However, only 10 of 350 cecal samples from slaughtered pigs were positive. There was little similarity between genotypic patterns for Arcobacter collected from the three farms. The level of genotypic variation revealed by PFGE suggested that pigs in this farrow-to-finish operation were colonized by multiple Arcobacter parent genotypes that may have undergone genomic rearrangement, common to members of Campylobacteraceae, during successive passages through the animals. Additionally, the level of genotypic diversity seen among Arcobacter isolates from farms of a single farrow-to-finish swine operation suggests an important role for genotypic phenotyping as a source identification and monitoring tool during outbreaks.