Transcriptional response of Clostridium difficile to low iron conditions.

Clostridium difficile (Cd) is the leading cause of antibiotic-associated diarrhea. During an infection, Cd must compete with both the host and other commensal bacteria to acquire iron. Iron is essential for many cell processes, but it can also cause damage if allowed to form reactive hydroxyl radicals. In all organisms, levels of free iron are tightly regulated as are processes utilizing iron molecules. Genome-wide transcriptional analysis of Cd grown in iron-depleted conditions revealed significant changes in expression of genes involved in iron transport, metabolism and virulence. These data will aid future studies examining Cd colonization and the requirements for growth in vivo during an infection.