Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/30/2005
Publication Date: 5/20/2006
Citation: Son, I., Englen, M.D., Berrang, M.E., Cray, P.J., Harrison, M.A. 2006. Genetic diversity of arcobacter and campylobacter on broiler carcasses during processing. Journal of Food Protection. 69(5):1028-1033.
Interpretive Summary: Campylobacter is the most common cause of acute bacterial gastroenteritis in humans worldwide, and poultry and poultry products are a major source of infection. Arcobacter is closely related to Campylobacter and has recently gained attention as an emerging foodborne pathogen. However, few reports have been published on the genetic diversity of Arcobacter and Campylobacter in U.S. poultry plants. The purpose of this study was to adapt Pulsed Field Gel Electrophoresis (PFGE) methodology for typing Arcobacter and to compare the diversity of Arcobacter and Campylobacter strains on broiler carcasses from a commercial poultry processing plant. Carcasses were sampled at three sites along the processing line: 1) pre-scalding, 2) pre-chilling, and 3) post-chilling. Samples were collected during five plant visits from September to October of 2004. PFGE groups of Arcobacter and Campylobacter strains were distributed among single-isolate and multi-isolate groups. A total of 33.1% of Arcobacter isolates belonged to single-isolate groups, while only 2.3% of Campylobacter isolates belonged to this category. The remaining Arcobacter species were distributed in 24 multi-isolate PFGE groups, while Campylobacter species were included in just eight multi-isolate groups. Our results demonstrate far greater genetic diversity for Arcobacter compared to that of Campylobacter, and suggest the Campylobacter groups are specific to individual flocks of birds processed on each sampling day.
Technical Abstract: Broiler carcasses (n=325) were sampled at three sites along the processing line (prescalding, prechilling, and post-chilling) in a commercial poultry processing plant during five plant visits from August to October 2004. Pulsed-field gel electrophoresis (PFGE) was used to determine the genomic fingerprints of Campylobacter coli (n=27), Campylobacter jejuni (n=188), Arcobacter butzleri (n=138), Arcobacter cryaerophilus 1A (n=4) and A. cryaerophilus 1B (n=31) with the resriction enzymes Sma1 and Kpn1 for Campylobacter and Arcobacter, respectively. Campylobacter species were subtyped by the Centers for Disease Control and Prevention PulseNet 24-h standardized protocol for C. jejuni. A modification of this protocol with a different restriction endonuclease (Kpn1) and different electrophoresis running conditions produced the best separation of restriction fragment patterns for Arcobacter species. Both unique and common PFGE types of Arcobacter and Campylobacter strains were identified. A total of 32.8% (57 of 174) of the Arcobacter isolates had unique PFGE profiles, whereas only 2.3% (5 of 125) of the Campylobacter isolates belonged to this category. The remaining Arcobacter strains were distributed among 25 common PFGE types; only eight common Campylobacter PFGE types were observed. Cluster analysis showed no associations among the common PFGE types for either genus. Each of the eight common Campylobacter types consisted entirely of isolates from one sampling day, whereas more then half of the common Arcobacter types contained isolates from different sampling days. Our results demonstrate far greater genetic diversity for Arcobacter than Campylobacter and suggest that the Campylobacter types are specific to individual flocks of birds processed on each sampling day.