Abstract
During an infection, bacterial pathogens must acquire iron from the host to survive. However, free iron is sequestered in host proteins, which presents a barrier to iron-dependent bacterial replication. In response, pathogens have developed mechanisms to acquire iron from the host during infection. Interestingly, a significant portion of the iron pool is sequestered within heme, which is further bound to host proteins such as hemoglobin. The copious amount of heme–iron makes hemoglobin an ideal molecule for targeted iron uptake during infection. While the study of heme acquisition is well represented in Gram-negative bacteria, the systems and mechanism of heme uptake in Gram-positive bacteria has only recently been investigated.
Bacillus anthracis
, the causative agent of anthrax disease, represents an excellent model organism to study iron acquisition processes owing to a multifaceted lifecycle consisting of intra- and extracellular phases and a tremendous replicative potential upon infection. This review provides an in depth description of the current knowledge of
B. anthracis
iron acquisition and applies these findings to a general understanding of how pathogenic Gram-positive bacteria transport this critical nutrient during infection.