Magnesium for Salmonella growth In mammals, macrophages are a first line of defense against pathogenic bacteria like Salmonella. These immune cells possess a metal-ion transporter called SLC11A1 or NRAMP1, which is known to be involved in infection resistance. Cunrath and Bumann studied mice that only differ in one allele of the SLC11A1 gene, which leaves mice either susceptible or resistant to infection. Proteomic analyses showed that bacteria isolated from mice with functional SLC11A1 alleles experienced metal starvation, particularly of magnesium. The resulting impairment of bacterial growth seems to be the primary mode of action of SLC11A1 against invading pathogens.