FIG. 1.

Colonization by wild-type B. pertussis, BP338, and the ΔbrkA mutant, RFBP2152, on day 3 postinoculation. Groups of three 4-to 6-week-old C57BL/6 mice were inoculated with 5 × 10⁵ CFU of BP338 (solid bars) or RFBP2152 (open bars) delivered in a 50-μl volume of PBS into the nares. The number of bacteria recovered from the nasal cavity, trachea, and lungs at 3 days postinoculation is expressed as the log₁₀ mean ± the standard error. Dashed line indicates limit of detection.