IDR - Immune Diagnostics & Research

Original Articles

Microarray analysis of virulence gene profiles in Salmonella serovars from food/food animal environment

Wen Zou, Sufian F Al-Khaldi, William S Branham, Tao Han, James C Fuscoe, Jing Han, Steven L Foley, Joshua Xu, Hong Fang, Carl E Cerniglia, Rajesh Nayak

Division of Personalized Nutrition and Medicine, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079, United States



Introduction: Rapid, accurate and inexpensive analysis of the disease-causing potential of foodborne pathogens is an important consideration in food safety and biodefense, particularly in developing countries.  The objective of this study is to demonstrate the use of a robust and inexpensive microarray platform to assay the virulence gene profiles in Salmonella from food and/or the food animal environment, and then use ArrayTrackTM for data analysis.   

Methodology:  The spotted array consisted of 69 selected Salmonella-specific virulence gene probes (65bp each).  These probes were printed on poly-L-lysine-coated slides.  Genomic DNA was digested with Sau3AI, labeled with Cy3 dye, hybridized to the gene probes, and the images were captured and analyzed by GenePix 4000B and ArrayTrackTM, a free software developed by Food and Drug Administration (FDA) researchers.

Results: Nearly 58% of the virulence-associated genes tested were present in all Salmonella strains tested.  In general, genes belonging to inv, pip, prg, sic, sip, spa or ttr families were detected in more than 90% of the isolates, while the iacP, avrA, invH, rhuM, sirA, sopB, sopE or sugR genes were detected in 40 to 80% of the isolates.  The gene variability was independent of the Salmonella serotype.

Conclusions: This hybridization array presents an accurate and cost-effective method for evaluating the disease-causing potential of Salmonella in outbreak investigations by targeting a selective set of Salmonella-associated virulence genes. 


Salmonella; virulence associated genes; microarray; pathogenicity

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