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United States Department of Agriculture

Agricultural Research Service

Title: Heterogeneities in Intergenic Regions Proximal to 23s Rrlh and 5s Rrfh Correlate with Evolutionary Divergence of Pathogenic Salmonella Serovars

item Morales, Cesar
item Guard, Jean

Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2005
Publication Date: June 1, 2005
Citation: Morales, C., Bouldin, J.G. 2005. Heterogeneities in intergenic regions proximal to 23s rrlh and 5s rrfh correlate with evolutionary divergence of pathogenic salmonella serovars. 105th General Meeting of the American Society for Microbiology, Atlanta, GA,June 5-9,2005.

Technical Abstract: Two intergenic regions defined as (I) the 179bp between the end of the 23S rrlH ORF and the start of the 5S rrfH ORF and (II) the 190bp between the end of the rrfH ORF and start of the transfer RNA aspU ORF of Salmonella enterica serovar Enteritidis were sequenced from multiple isolates of 4 different pathogenic Salmonella enterica serovars, namely Typhimurium, Pullorum, Heidelberg, and Enteritidis. Region I of Enteritidis shared 98.3% nucleotide identity with serovars Pullorum and Gallinarum and 66.1% and 67.2% identity with serovars Typhimurium and Heidelberg, respectively. Thus, there was an evolutionary divergence between Salmonella O-serovars D1 and B. Region II of serovar Heidelberg had 100% and 99.5% identity with serovars Enteritidis and Gallinarum, respectively, and 91.3% identity with serovar Typhimurium. This result is important, because other Salmonella serotypes may be evolving an ability to contaminate the internal contents of eggs. Some strains of serovar Pullorum lacked a 137bp segment in the ISR II region that contained a duplicated 19bp element on each end of the segment; thus, an insertion event may result in different evolutionary paths between and within serovars. These results indicate that the sequences of the rrlH-rrfH and rrfH-aspU regions are useful for following evolutionary trends in the pathogenic Salmonellae and that they could be used for bacterial and serovar identification in epidemiological studies.

Last Modified: 4/18/2015