Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: January 2, 2005
Publication Date: June 7, 2005
Citation: Morales, C., Bouldin, J.G. 2005. Linkage of 23s rrlc and rrla single nucleotide polymorphisms to phenotypic divergence of salmonella enteritidis [CD ROM]. Version B-199, Washington, D.C., ASM. Technical Abstract: Salmonella enteritidis is the only Salmonella serovar out of over 2500 that efficiently contaminates the hen egg and that causes substantial food borne illness. It is currently the world's leading cause of human salmonellosis, which is an epidemiological prominence that it has held since the early 1980s. The infection cycle from farm to human is complex and it appears to require that S. enteritidis generate unusual and complementary phenotypes if it is to be completed. This laboratory is especially interested in identifying a genetic basis for the generation of phenotypic heterogeneity. This has been a quioxotic challenge, because evidence from genetic fingerprinting, DNA microarrays and Phenotype Microarray' analysis (see related abstracts, this meeting) strongly suggests that single nucleotide polymorphisms (SNPs), as compared to larger scale genetic recombination, gene acquisition or rearrangement events, culminate in at least a bimodal pattern of gene expression for this pathogen. To approach this problem of identifying specific SNPs that are linked with the evolution of egg contamination and avian reproductive tract tropism, we applied a modification of the two-enzyme (PstI and SphI) ribotype fingerprinting protocol developed at DEFRA, UK to different phenotypes of S. enteritidis. These phenotypes differ in their ability to produce biofilm and high-molecular-mass lipopolysaccharide. SNPs located in the 23s ribosomal genes rrlC and rrlA correlated with phenotypic heterogeneity in both PT13A and PT4 S. enteritidis. These results suggest that these specific SNPs will be useful for genetic characterization of S. enteritidis strains that vary in their ability to contaminate eggs.