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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetic Analysis of Poultry-Associated Salmonella enterica to Identify and Characterize Properties and Markers Associated with Egg-Borne Transmission of Illness

Location: Egg Safety and Quality

Title: Use of Intragenic Sequence Ribotyping (ISR) for serotyping Salmonella obtained from poultry and their environment

Authors
item Pulido-Landinez, Martha -
item Sanchez-Ingunza, Roxana
item GUARD, JEAN
item Pinheiro Nascimento, Vladimir -

Submitted to: American Association of Avian Pathologists
Publication Type: Abstract Only
Publication Acceptance Date: January 23, 2012
Publication Date: August 5, 2012
Citation: Pulido-Landinez, M., Sanchez-Ingunza, R., Guard, J.Y., Pinheiro Nascimento, V. 2012. Use of Intragenic Sequence Ribotyping (ISR) for serotyping Salmonella obtained from poultry and their environment. American Association of Avian Pathologists. p. 17.

Technical Abstract: BACKGROUND: The dkgB-linked ribosomal region of Salmonella enterica flanking a 5S gene shows genetic heterogeneity that distinguishes closely related serovars such as Enteritidis, Dublin, Gallinarum and Pullorum (Morales et al, 2006). We wanted to know how sequence-based ISR compared to the traditional Kauffman-White (KW) scheme for characterizing serotype of 155 isolates collected from poultry and their environment in the south of Brazil. APPROACH: To conduct Intergenic Sequence Ribotyping (ISR), the region neighboring the gene dkgB was sequenced from the end of the 23S gene to the start of the tRNA aspU. Fast PCR (Veriti) and F/R primers were used to generate product for sequencing, which ranged in size from approximately 250 to 550bp. Isolates cost approximately $12 per sample to process. RESULTS: Of the 155 isolates processed, 11 (7.1%) may have been mixed, because KW and ISR results were different. Of 144 isolates, 13 (9.0%) had unique ISR sequences that were not reported in databases for reference strains. Of the remaining 131 cultures, serotypes that were identified similarly by both methods were Enteritidis, Heidelberg, Hadar, Typhimurium, Gallinarum and Agona. SUMMARY: ISR is a sensitive molecular method that can be used to identify serotypes of Salmonella enterica that are circulating in the environment of poultry. ISR uses both forward and reverse sequencing reactions, which facilitates detection of mixed serotypes. ISR may be a more stringent method than KW for classification of serotype, thus it is not unexpected that new genetic variants were found that are not yet in the reference databases.

Last Modified: 9/10/2014
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