Viability of, and transfer of a plasmid from, E. coli K12 in the human intestine.

THE controversy over the ability of Escherichia coli K12 to survive in the human gut and to transfer plasmids to the indigenous flora, arose in relation to proposed research on bacterial plasmids and other genetic agents hybridised with DNA from organisms unrelated to the normal hosts of the plasmids or to the plasmids themselves. As the bacterial strain used in most studies of microbial genetics is E. coli K12, experiments were designed to investigate its viability, and its capacity for plasmid transfer to the resident E. coli, in the human intestine. A preliminary summary of our observations was presented to the Working Party headed by Lord Ashby1.