Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/2001
Publication Date: N/A
Interpretive Summary: Phage typing has become an important epidemiological tool in identifying sources of Salmonella enteritidis (SE) outbreaks. Several molecular typing methods were evaluated for their discriminatory power to identify genetic differences among different SE phage types isolated in Europe and the U.S. Pulsed-field gel electrophoresis (PFGE) identified a single DNA pattern among the different SE phage types. Comparing the nucleotide sequences for several Salmonella virulence genes failed to identify a single nucleotide change in the gene sequences from most SE isolates, regardless of phage type. Based on these results, it appears that the different SE phage types are genetically related or clonal. However, using primers 1283 and Opa4, it was possible to not only differentiate SE isolates from different geographic locations, but within a specific geographic locale as well using Random Amplified Polymorphic DNA PCR. Any chance for discerning genetic differences among isolates will need to rely on molecular techniques other than PFGE.
Technical Abstract: Phage typing is a prominent method for identifying particular Salmonella enteritidis (SE) strains associated with human disease outbreaks. The present study evaluated several molecular typing methods for their to discriminate between SE phage types based on genetic differences. Pulsed-field gel electrophoresis (PFGE) did not provide this discrimination, as it identified a single DNA pattern common to the variou phage types. Based on the PFGE results, isolates of different phage types appear to be genetically related. However, using two different primers in Random Amplified Polymorphic DNA PCR, SE isolates from different locations (and even within a defined geographic location) could be discriminated from each other.