FIG. 1.

B. bronchiseptica survives in MH-S macrophages 20 h after phagocytosis, whereas B. pertussis does not. The columns represent the percentage of surviving bacteria. The time scale refers to the time after elimination of the extracellular bacteria by gentamicin treatment and extensive washing of the cells, when the number of intracellular bacteria of each strain was set as 100%. Each experiment was carried out at least three times in duplicate. The vertical bars indicate the standard deviations.