Mycobacterium tuberculosis (Mtb) remains a leading cause of infectious disease mortality worldwide, largely due to its ability to survive within host macrophages. Despite advances in understanding the environmental pressures Mtb encounters in vivo, the genetic requirements for adaptation and survival within the intracellular niche remain incompletely defined. Here, we employed a genome-wide CRISPR interference (CRISPRi) screen in an ex vivo model exploiting single-cell suspensions from Mtb-infected mouse lung homogenates to identify genes critical for intracellular survival at different time points in the infection continuum. This novel approach enabled us to identify how different bacterial metabolic pathways were of greater importance to the bacterium at different time points post-infection. The results provide insights into how the evolving immune response to infection shapes the metabolic and replicative status of the bacterium. This information has significance in the design of therapeutic strategies toward cure.
Theriault et al. (Mon,) studied this question.