Unexpectedly, we found remarkably divergent in vivo requirements for central pathways between these two pathogens during UTI by assessing the in vivo fitness of strains containing mutations in pgi, pfkA, tpiA, pykA, gnd, talB, edd, sdhB, fumC, frdA, and pckA, in both uropathogenic E. coli CFT073 and P. mirabilis HI4320 (Fig. 1). This evidence concerns the gene FXN and bacterial urinary tract infection.