title: Colonization of R plasmid-bearing Escherichia coli strains in the mouse alimentary tract.
abstract: In order to examine the ability of R plasmid-bearing Escherichia coli strains to colonize in the mouse alimentary tract, an R plasmid-positive (R(+)) E. coli strain and its R plasmid-negative (R(-)) counterpart were together inoculated into the streptomycin-treated mouse alimentary tract, and the numbers of fecal E. coli strains were enumerated. The numbers of R(+) strains were always at the level similar to or lower than those of their counterparts and rapidly decreased in the fecal population. However, when R plasmids, which were originated from a cryptic plasmid of the host E. coli strain, were utilized, an R(+) strain dominated over its R(-) counterpart during the experimental period. These experimental results indicated that the relationship between the host strain and R plasmids affected the ability of the host strain to colonize in the alimentary tract.
authors.affiliation: Laboratory Animal Center, School of Medicine, Keio University, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Shimoda
authors.forename: T
authors.initials: T
authors.lastname: Kuhara
authors.forename: K
authors.initials: K
authors.lastname: Maejima
mesh_terms: D000818:Animals; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology*; D007422:Intestines / Q000382:microbiology*; D051379:Mice; D008813:Mice, Inbred ICR / Q000382:microbiology*; D011815:R Factors