The effect of the C57BL/6 and BALB/c background on S. Typhimurium infection is not restricted to the mutation in Nramp1, however, as illustrated by the observation that transgenic C57BL/6 mice expressing functional Nramp1 still succumb to infection, which is not the case of 129 mice (Monack et al., 2004; Loomis et al., 2014). Here, SLC11A1 is linked to infection.