Emergence of biofilm-forming subpopulations upon exposure of Escherichia coli to environmental bacteriophages

Exposure of Escherichia coli MG1655 to environmental bacteriophages results in rapid selection for phagetolerant subpopulations displaying increased biofilm formation. Analysis of one phage-tolerant strain revealed large amounts of the DNA-binding Dps protein in the outer membrane protein and production of fimbria-like structures. In dps and fimA mutant derivatives of MG1655, no selection of phage-tolerant bacteria upon exposure to bacteriophages occurred, suggesting a role for Dps and type I pili in bacteriophage tolerance.