The Different Types of Metallophores Produced by Salmonella enterica: A Review

Salmonella enterica (S. enterica) serovars Enteritidis and Typhimurium are the main causes of bacterial gastroenteritis worldwide. This Gram-negative rods bacterium possesses several virulence factors that enable it to survive the host's nutritional immunity. Toxins and metallophores are among these factors. Heavy metals, in particular, are essential for the survival of all living organisms including bacteria. During infection, S. enterica competes with the host for the available heavy metals by secreting metallophores, which are secondary metabolites. Once produced in the extracellular medium, metallophores complex heavy metals thus allowing Salmonella to acquire metal ions through importing them via channels embedded in their membranes. This review highlights the biosynthesis, export, import, and genetic regulation of different metallophores synthesized by this germ.