At late time points (> 2 weeks) during experimental mouse infections, UPEC is reported to reside within LAMP1-positive and Cathepsin D-negative compartments (resembling late endosomes) in vivo[11,62]. How UPEC survive within these acidic environments and how the phagosome is modified or phagosome maturation is arrested has yet to be fully determined. This evidence concerns the gene CTSD and infection.