Figure 3.

Selected adaptive mechanisms used by bacterial pathogens to survive within their hosts. These mechanisms include secretion and delivery of effectors which interfere with the host cytoskeleton and immune signaling. pH-, iron- and oxygen-dependent bacterial sensors can be activated to modulate expression of their regulons, leading to gene expression reprogramming and favoring bacterial adaptation. Dedicated bacterial enzymes can be used (i) to metabolize nutrients and (ii) to reduce or oxidize metabolites present in the host environment, both reactions conferring to the pathogen, an advantage over the competing microbiota.