A survey of Col plasmids in natural isolates of Escherichia coli and an investigation into the stability of Col-plasmid lineages Riley, Margaret A. and Gordon, David M.,, 138, 1345-1352 (1992), doi = https://doi.org/10.1099/00221287-138-7-1345, publicationName = Microbiology Society, issn = 1350-0872, abstract= A survey of colicins in the ECOR reference collection of Escherichia coli is presented. Twenty-five of the 72 ECOR strains exhibited a phenotype consistent with colicin production and E. coli isolated from human hosts were more likely to be colicinogenic than those from animal hosts. Multiple representatives of two Col plasmids, lowmolecular-mass ColE1 plasmids and high-molecular-mass, conjugative ColIa plasmids were isolated from the ECOR collection and were examined with a combination of restriction fragment and Southern analysis. These data suggested that ColE1 plasmids comprise a stable (cohesive) plasmid lineage, while ColIa plasmids represent a family of distinct plasmid lineages united by the presence of the colicin Ia operon., language=, type=