CSE1L and infection: These newfound roles of the S. Typhi CRISPR-Cas system in the resistance to sodium deoxycholate and biofilm production should contribute toward the understanding of the evolutionary conservation of this system in the Salmonella genus, since these biological processes are relevant for the establishment of a successful infection cycle (Gonzalez-Escobedo et al., 2011; Spector and Kenyon, 2012).