Determination of the gene content of Salmonella genomes by microarray analysis.

Microarray technology provides a convenient and relatively inexpensive way of investigating the genetic content of bacterial genomes by comparative genomic hybridization. In this method, genomic DNA of an unknown bacterial strain of interest and that of a closely related sequenced isolate are hybridized to the same array. Hybridization signals are subsequently translated into gene absence and presence predictions for the experimental strain. Our nonredundant microarray of PCR products representing almost all genes from a number of the sequenced Salmonella enterica serovars (including Typhimurium, Typhi, Paratyphi A, and Enteritidis) allows accurate predictions of gene presence and absence in hundreds of Salmonella isolates on whole genome scale, for a fraction of the cost of complete genome sequencing, or resequencing using tiled oligo-arrays.