FIG. 6.
Biofilm mutants are severely compromised in their ability to colonize the mouse nasopharynx. A set of 29 biofilm mutants isolated in vitro were tested for their ability to colonize the mouse nasopharynx. These fell into three categories of colonization fitness: (A) highly deficient, (B) deficient, or (C) competent. Mutant and wild-type bacteria were grown to mid-log phase, washed in PBS, mixed 1:1, and then inoculated into the nares of C57BL/6 mice (1 × 107 CFU/mouse, 5 μl/nostril). Mice were sacrificed 5 days later, and bacterial counts in their nasopharyngeal lavage fluids were determined by plating for CFU. CI values were calculated by dividing the numbers of CFU for the mutant by those for the wild type. The median for each group is shown by the horizontal bar. In vivo CI values were significantly different from in vitro CI values (P ≤ 0.005).