Fig. 5

Growth competition among E. coli isolates from CRC patients and healthy controls. Lanes: 1, λ ladder as molecular size marker; 2, ccpm6195; 3, ccpm5172; 4, ccpm5062; 5, a mixture of ccpm6195, 5172 and 5062 before the competition assay; 6, a mixture of ccpm6195, 5172 and 5062 cultured in LB broth at the end of the competition assay; 7, a mixture of ccpm6195, 5172 and 5062 cultured in M9 medium at the end of the competition assay. Remarkably, after culture for 10 days in M9 medium, only ccpm6195 (see lane 7, the E. coli strain from a CRC patient, in which the genomic cleavage pattern is indistinguishable with that in lane 2) survived. These growth competition assays demonstrate that when nutrient was ample (as in LB broth), the three E. coli strains did not interfere with one another for growth; but when the nutrient was limited, the E. coli strains from a CRC patient had greater capabilities to compete for nutrient to grow