Development of a DNA Microarray for Molecular Identification of All 46 Salmonella O Serogroups

Abstract

e Salmonella is a major cause of food-borne disease in many countries. Serotype determination of Salmonella is important for disease assessment, infection control, and epidemiological surveillance. In this study, a microarray system that targets the O antigen-specific genes was developed for simultaneously detecting and identifying all 46 Salmonella O serogroups. Of these, 40 serogroups can be confidently identified, and the remaining 6, in three pairs (serogroups O67 and B, E1 and E4, and A and D1), need to be further distinguished from each other using PCR methods or conventional serotyping methods. The microarray was shown to be highly specific when evaluated against 293 Salmonella strains, 186 Shigella strains, representative Escherichia coli strains, and 10 strains of other bacterial species. The assay correctly identified 288 (98%) of the Salmonella strains. The detection sensitivity was determined to be 50 ng genomic DNA per sample. By testing simulated samples in a tomato background, 2 to 8 CFU per gram inoculated could be detected after enrichment. This newly developed microarray assay is the first molecular protocol that can be used for the comprehensive detection and identification of all 46 Salmonella O serogroups. Compared to the traditional serogrouping method, the microarray provides a reliable, high-throughput, and sensitive approach that can be used for rapid identification of multiple Salmonella O serogroups simultaneously.

Structural diversity inSalmonellaO antigens and its genetic basis

“…The completion of the sequencing of the Salmonella O-antigen gene clusters provides the data for a comprehensive typing scheme for Salmonella using sequence diversity, but based on the serotyping scheme, to give in effect molecular serotyping. To facilitate this, we have included data on the specific genes that could be useful for this and also a comprehensive set of primers that we have developed for a microarray targeting the O-antigenspecific genes that can differentiate most Salmonella serogroups (Table S5) (Guo et al, 2013). The only exceptions are groups A and D1 that need to be further distinguished from each other using conventional serotyping methods, due to having near-identical O-antigen gene clusters.…”

Comparing the ability of luminex xMAP®salmonella serotyping assay and traditional serotyping method for serotyping salmonella isolated from southern Chinese population

“…Microarray technology is being developed to characterize Salmonella serotypes (Guo et al . ; Shin et al . ).…”

“…Moreover, it was difficult to provide backward-compatible historical epidemiologic data. Microarray technology is being developed to characterize Salmonella serotypes (Guo et al 2013;Shin et al 2014). The microarray chip is prohibitively expensive and less cost-effective since it is restricted to one sample per slide.…”

Molecular Tools To Study Preharvest Food Safety Challenges

“…DNA microarray is considered a rapid and sensitive pathogen detection technique that overcomes the limitations of PCR-based methods (9,51). Microarrays allow a large number of specific DNA sequences to be detected simultaneously.…”

“…Several microarrays have been developed for the detection of foodborne pathogens (51,(54)(55)(56)(57)(58)(59)(60)(61)(62). For instance, Guo et al developed a microarray system for simultaneous identification of 46 Salmonella O serogroups targeting O antigen-specific genes.…”