Among this category of fitness factors are fimbrial genes (mrpA`and mrpF`from the mrp` operon, and pmpG), components of the flagellar cascade and regulation of motility (flhC, fliF, fliI, cheR), and components of the urease operon (ureG for single-species infection and ureRDCF for polymicrobial infection). Here, FLII is linked to infection.