ARS | Publication request: Analysis of Campylobacter jejuni whole genome DNA microarrays: significance of prophage and hypervariable regions for discriminating isolates

Submitted to: International Association for Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: March 2, 2011
Publication Date: July 31, 2011
Citation: Pittenger, L., Frye, J.G., Lindsey, R.L., McNemey, V., Reeves, J., Cray, P.J., Harrison, M.A., Englen, M.D. 2011. Analysis of Campylobacter jejuni whole genome DNA microarrays: significance of prophage and hypervariable regions for discriminating isolates. International Association for Food Protection Annual Meeting. July 31 - August 3, 2011. Milwaukee, WI.

Technical Abstract: Introduction: Campylobacter jejuni is a major cause of gastroenteritis in humans and is carried in many common food animals. In order to reduce human infections a better understanding of Campylobacter epidemiology is needed. Identifying genes that enable discriminating between isolates is an important factor in filling this need. A useful technique for this purpose is comparative genome indexing (CGI) using whole genome DNA microarrays. Purpose: The objective of this study was to use CGI to identify the genes that were most significant for discriminating isolates of C. jejuni from humans, chickens, and beef cattle. Methods: A geographically diverse population of 95 C. jejuni strains was selected from a collection of human, cattle and chicken isolates. Genomic DNA from each isolate was labeled and hybridized to microarrays composed of C. jejuni strains NCTC11168 (human isolate acquired from the America Type Culture Collection (ATCC); the isolate was originally isolated in the UK in 1980) and RM1221 (chicken isolated in the U.S. in 2000) genes. The SAS program was used to analyze the presence or absence of genes and determine which variable genes were most informative. Results: Statistical analyses of whole genome data from 95 geographically diverse cattle, chicken and human C. jejuni isolates identified a total of 142 most informative (i.e. significantly variable) genes. Of this total, 125 (88%) belonged to genomic prophage and hypervariable regions. Prophage and hypervariable genes were identified in isolates from all 3 hosts but were especially common in human isolates. Significance: The significance of genomic prophage and hypervaiable regions in determining C. jejuni isolate genomic diversity is emphasized by these results. These genes should prove useful in the development of a more efficient genotyping system for C. jejuni as well as furthering our understanding of the epidemiology of this major food-borne pathogen.