FIG. 4.

The three non-IBC-forming isolates, rUTI1, acute4, and pyelo3, were deficient in invasion in vivo. Female C3H/HeN mice were inoculated with UTI89, rUTI1, acute4, and pyelo3. At 1 h postinfection, bladders were removed and processed. The luminal fraction represents luminal bacteria, and the intracellular fraction represents invaded bacteria. One hour after inoculation, 4.4% of UTI89 bacteria invaded, whereas for rUTI1, acute4, and pyelo3, only 0.3%, 0.5%, and 1.1% of luminal bacteria invaded, respectively. Thus, the three non-IBC-forming isolates invade poorly relative to UTI89.