Location: Egg Safety & Quality ResearchTitle: Use of FTA Cards for the Transport of DNA Samples of Salmonella spp. from Poultry Products from Southern Brazil. Author
Submitted to: Acta Veterinaria
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/6/2012
Publication Date: 9/14/2012
Citation: Pulido-Landinez, M., Laviniki, V., Sanchez-Ingunza, R., Guard, J.Y., Pinheiro Nascimento, V. 2012. Use of FTA Cards for the Transport of DNA Samples of Salmonella spp. from Poultry Products from Southern Brazil. Acta Scientia Veterinariae. 40(4):1073. Interpretive Summary: Salmonella enterica is an important food borne pathogen that threatens the safety and security of food everywhere. Determining serotype of strains suspected of causing food borne illness is a first step to understanding how to reduce risk, because only about two dozen of over 2600 serotypes routinely sicken people. Determining serotype can be expensive and time-consuming, and it often fails. This study applies a method of serotyping designed to maintain accuracy while reducing costs as much as 80%. One barrier to application of the method, which is known as Intragenic Sequence Ribotyping (ISR), on an international scale was that barriers exist to shipping living pathogens around the world. To overcome this barrier, we applied cells to a card material called FTA, which kills living cells and releases DNA. After obtaining appropriate clearance, DNA from field isolates of Salmonella enterica were shipped from Brazil to the United States. Results indicate that FTA cards can be used to ship DNA of Salmonella enterica internationally and that serotype can be determined by ISR after shipment.
Technical Abstract: Background: The contamination of products with Salmonella is a major threat to the poultry industry because the possible transmission to humans and animals can produce a huge negative impact. The diversity of Salmonella enterica serotypes complicates the diagnostic systems and the transport of live cultures to the diagnostic labs may represent a biohazard. Current methods for serotyping using antibodies do not work well for many Salmonella serotypes and reagents are not often available. For these reasons, methods that assign serotype by the analysis of DNA are preferred. One step that is currently in development is streamlining methods for DNA submission to the laboratories for sequencing. For this purpose, we investigated fi lter papers commercially available (Flinders Technology Associates - FTA) to ship DNA samples. Filter papers are impregnated with a chemical formulation that lyses cells, immobilizes DNA, and protects it from degradation. The objective of this study was to assess the feasibility of the FTA cards for transporting Salmonella DNA samples in order to reduce biohazards and if they would yield enough DNA in quantity and quality for molecular analyses. Material, Methods & Results: In this study 156 samples of Salmonella enterica serotypes Enteritidis, Heidelberg, Hadar, Gallinarum, Typhimurium, Agona and Pullorum were isolated from poultry products and environments in southern Brazil. Samples were stored in the Avian Diagnostic and Research Center of the Federal University of Rio Grande do Sul. Following instructions for spotting cards with cell cultures at a density that visually matched a McFarland Turbidity Standard 0,5; they were shipped to the Agriculture Research Service of the United States Department of Agriculture (USDA-ARS, Athens, GA-USA), using FTA cards. Upon the reception of the cards, safety testing was performed by transferring one disk from each sample into 10 mL of brain heart infusion (BHI) tubes and incubated at 37°C for 24 h. The BHI tube that showed turbidity after incubation was transferred to brilliant green (BG) agar and incubated at 37°C for 24 h to 48 h. If