FIG 1.

Milk swimming plates. Shown are examples of two E. coli strains on milk swimming plates. The first is strain T2 (A), which is a slower swimmer, and the second is P1 (B), a faster swimmer. The relative swimming abilities of these two strains on the milk swimming plates are consistent with data on the traditional swimming plate with the exception that growth is much slower. (C) Combined results from three swimming assays on skim milk plates. There is a significant difference between the persistent- versus transient-infection groups (P < 0.001). In addition, all three P strains are significantly different from all three T strains. Different lowercase letters indicate significantly different means. Error bars represent the standard errors of the means.