Fig 5.

Determination of the optimal dose for STEC 88-0643 in BALB/c mice with intact intestinal flora. A mixture of wild-type STEC 88-0643 and Δure mutant in a 1:1 ratio was administered intragastrically to 6-week-old female BALB/c mice. (A) The number of surviving mice was recorded for 7 days postinfection and plotted as percent survival for groups of 3 mice each that were inoculated with H₂O, 10⁸ CFU, or 10⁹ CFU bacteria and for the total of 24 mice receiving 10¹⁰ CFU bacteria. (B) For the groups of mice inoculated with 10¹⁰ CFU, the numbers of mice that remained colonized with wild-type STEC 88-0643 and the Δure mutant were recorded for 7 days after the inoculation. The results are depicted as percent mice colonized, where 100% corresponds to the 17 mice that survived from the total of 24 administered the 10¹⁰ CFU dose.