FIG. 7.

Lack of O antigen does not impair resistance to polymyxin B. (A) LPS phenotypes of K56-2 and RSF19. (B) Number of CFU prior to challenge (Starting CFU) and 2 h after incubation in the absence (Buffer) or presence (Polymyxin B) of 100 μg/ml polymyxin B. The data points and error bars indicate means and standard deviations of data from one representative experiment done in triplicate. Significant differences were determined using unpaired t tests. The asterisk indicates that the P value is <0.05 for the statistical difference between the polymyxin B and buffer treatments.