Abstract

Salmonellosis is an infectious disease affecting human and animals. The virulence of Salmonella is a function of chromosomal and plasmid factors, many genes code for these factors. Salmonella genes can be classified as core (housekeeping) genes and accessory genes. The core genes of a species are those genes found in (nearly) all known members of the species and they include mostly genes that are necessary for the cell to survive and grow, these include gene encoding enzymes which function in biosynthetic pathways. Genes in the accessory genome are those unique to particular strains and are mainly in the following groups: genomic islands including Salmonella Pathogenicity islands (SPls), prophages, insertion sequences.

Keywords: Genes, Pathogenicity, Resistance, Salmonella, Virulence.