1. Development of a New Molecular Subtyping Tool for Salmonella enterica Serovar Enteritidis Based on Single Nucleotide Polymorphism Genotyping Using PCR
- Author
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John Devenish, Sebastien Belanger, Dele Ogunremi, Andrée Ann Dupras, and Hilary Kelly
- Subjects
Microbiology (medical) ,Genetics ,Molecular Epidemiology ,Genotype ,Molecular epidemiology ,Salmonella enteritidis ,Genetic Variation ,Bacteriology ,Biology ,Polymerase Chain Reaction ,Polymorphism, Single Nucleotide ,Subtyping ,law.invention ,Molecular Typing ,law ,Pulsed-field gel electrophoresis ,Animals ,Cluster Analysis ,Humans ,Typing ,Genotyping ,Polymerase chain reaction ,Phage typing - Abstract
The lack of a sufficiently discriminatory molecular subtyping tool for Salmonella enterica serovar Enteritidis has hindered source attribution efforts and impeded regulatory actions required to disrupt its food-borne transmission. The underlying biological reason for the ineffectiveness of current molecular subtyping tools such as pulsed-field gel electrophoresis (PFGE) and phage typing appears to be related to the high degree of clonality of S . Enteritidis. By interrogating the organism's genome, we previously identified single nucleotide polymorphisms (SNP) distributed throughout the chromosome and have designed a highly discriminatory PCR-based SNP typing test based on 60 polymorphic loci. The application of the SNP-PCR method to DNA samples from S . Enteritidis strains ( n = 55) obtained from a variety of sources has led to the differentiation and clustering of the S . Enteritidis isolates into 12 clades made up of 2 to 9 isolates per clade. Significantly, the SNP-PCR assay was able to further differentiate predominant PFGE types (e.g., XAI.0003) and phage types (e.g., phage type 8) into smaller subsets. The SNP-PCR subtyping test proved to be an accurate, precise, and quantitative tool for evaluating the relationships among the S . Enteritidis isolates tested in this study and should prove useful for clustering related S . Enteritidis isolates involved in outbreaks.
- Published
- 2014