Similarly, it was recently shown that the oxidative fumarase FumC is essential for fitness during UTI pathogenesis, but this essentiality appears to be predominantly associated with the role FumC plays in coping with iron limitation, via its ability to function enzymatically without an Fe-S cluster, rather than its specific role in the tricarboxylic acid (TCA) cycle (77). This evidence concerns the gene FH and bacterial urinary tract infection.