Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/11/2006
Publication Date: 10/11/2006
Citation: Olson, A.B., Andrysiak, A.K., Bouldin, J.G., Ng, L. 2006. Limited Genetic Diversity in Salmonella enterica Serovar Enteritidis PT13 (meeting abstract). Canadian Federal Food Safety & Nutrition meeting. p. 147 Interpretive Summary:
Technical Abstract: Salmonella enterica serovar Enteritidis has emerged as a significant food-borne pathogen throughout the world and it is commonly characterized by phage typing (PT). In Canada, PT4, 8 and 13 are the predominant PTs. Epidemiological subtyping of Salmonella is typically done by PFGE but plasmid profiling and ribotyping are also used. Comparative genomics were used on PT13 strains isolated over a two year span from geographically related and unrelated strains to identify epidemiologically significant genetic determinants. PFGE showed a predominance of a single macro restriction pattern and plasmid profiling showed similar results. Comparative genomic hybridizations using an oligonucleotide array based upon chromosomal coding sequences of S. enterica serovar Typhimurium strain LT2 and the Salmonella genomic island 1 successfully determined major genetic differences between Typhimurium and Enteritidis PT13, but no major strain-to-strain differences were observed between PT13 isolates. Individual loci (ccmB, umuC, fljA, safA and fliC) that were identified as potentially divergent in the CGH data set were screened and/or sequenced in a panel of PT13 and non-PT13 Enteritidis strains, and no polymorphisms were detected between the PT13-encoded loci. Sequence-based typing using established loci (fimA, mdh, manB, cyaA, caiC, dmsA, ratA and STM0660) was performed and these loci also showed no diversity amongst PT13 strains; however, this PT did encode conserved polymorphisms when compared to other Enteritidis PTs. Greater than 11, 000 base pairs of sequence for each PT13 strain was analyzed without finding genetic diversity. These data suggest that Canadian PT13 strains are highly related genetically.