Figure 4.

The distribution of the modified commensal donor E. coli strain in the mouse gut at the end of the ten-day experiment. The open circles show the total number of bacterial cells with and without RP4 plasmid as determined by serial dilution plating on MacConkey agar containing chloramphenicol, while the filled circles show the mice with donor bacteria carrying RP4 plasmid as determined by serial dilution plating on MacConkey agar containing chloramphenicol and ampicillin. Each symbol represents an individual mouse in the group (n = 5); 100 CFUs per gram fecal material was the lower limit of detection.