FIG 7 .
In vivo phage predation selects for E. faecalis PIPEF mutants. Germfree C57BL6/J mice were orally inoculated with E. faecalis V583 followed by an oral treatment of φVPE25. (A) Fecal burden of E. faecalis from mice with and without phage treatment over a 9-day period. Each symbol represents the value for an individual mouse, and the short black bar represents the mean of the group of mice. The means that are significantly different (P < 0.001) by Student’s t test are indicated by a bar and asterisk. (B) φVPE25 particle numbers from gnotobiotic mouse feces as determined by a plaque assay. (C) Percentage of φVPE25-resistant E. faecalis clones isolated from gnotobiotic mice following phage treatment. The percentage of φVPE25 resistance was calculated by determining the number of phage-resistant isolates by cross streaking and then dividing the number of resistant isolates by the total number of isolates acquired at each time point and multiplying by 100. Symbols: ♦, treated with φVPE25; ●, not treated with phage.