DNA Microarray for Molecular Epidemiology of Salmonella

Salmonellosis is a common infection estimated to affect 3 billion people and to cause 200,000 deaths every year. Infections can appear as enteric fever, gastroenteritis, bacteremia, or extraintestinal focal infection. The course of the disease depends on a variety of factors, including infective dose, immune status of the host, and the genetic background of both the host and the pathogen. It has been recognized that certain Salmonella types play a major role in the epidemiology of Salmonella . Here we describe a DNA microarray comprised of 282 sixty-mer oligonucleotide probes to study the epidemiology of Salmonella enterica subsp. enterica isolates at the genotypic level. The probes detect targets encoding genes associated with pathogenicity, antibiotic resistance, fimbriae, prophages, flagella (H antigens), lipopolysaccharides (O antigens), plasmids, insertion sequence elements, and metabolism. The probes are printed on glass slides, and whole-genomic fluorescence-labeled Salmonella DNA is hybridized to the substrate. For quality assurance, a number of controls are included on the microarray.