Cyclic di-AMP (c-di-AMP) is a bacterial signaling nucleotide synthesized by 
several human pathogens. This widespread and specific bacterial product is 
recognized by infected host cells to trigger an innate immune response. 
Detection of c-di-AMP in the host cytosol leads primarily to the induction of 
type I interferon via the STING-cGAS signaling axis, while being also entangled 
in the activation of the NF-κB pathway. During their long-standing interaction, 
host and pathogens have co-evolved to control c-di-AMP activation of innate 
immunity. On the bacterial side, the quantity of c-di-AMP released inside cells 
allows to manipulate the host response to exacerbate infection by avoiding 
immune recognition or, at the opposite, by overloading the STING-cGAS pathway.