The complex role of nicotinic acid metabolism in the genus Bordetella.

Bacteria obtain nutrients and other essential factors from their immediate surrounding. For bacteria that reside in a specialized or limited niche range, their metabolism reflects adaptation to that environment(s). Bordetella pertussis and B. parapertussis have evolved from a B. bronchiseptica-like ancestor that survives within hosts and in the environment to become restricted to a single niche, the human respiratory tract. This restriction has shaped their metabolism. Here, the multifaceted role of nicotinic acid in Bordetella biology is reviewed. It serves as a precursor for the synthesis of NAD, for which these Bordetella are auxotrophic, but also induces profound changes in gene expression profiles in a concentration-dependent manner. While these Bordetella display very high levels of conservation in many aspects, they differ in their utilization of nicotinic acid. Understanding the consequences of this difference may shed light on host-pathogen interactions of these niche specialized species.