FIG. 5.
Colonization of the mouse respiratory tract by wild-type and mutant (bvgS-I1 carrying) B. pertussis strains. Groups of mice were inoculated intranasally with 50 μl of PBS containing 106 CFU of one of the experimental strains (GMT1, GMT1i, and Tohama I). At days 0 (three mice at least) and 8 (five mice at least), the animals were sacrificed, and colonization at various sites of the respiratory tract was determined. Error bars represent 1 standard deviation. The dashed line indicates the lower limit of detection. The asterisks denote a statistically significant difference (**, P < 0.01; ***, P < 0.001) between the two specified groups.