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Published on: April 9, 2018
Colonization of R plasmid-bearing Escherichia coli strains in the mouse alimentary tract
K Shimoda1, T Kuhara, K Maejima
1Laboratory Animal Center, School of Medicine, Keio University, Tokyo, Japan.
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.
Insights
The origin of R plasmids significantly impacts Escherichia coli colonization in mouse intestines. R plasmids from the host strain enhanced E. coli gut colonization, unlike other R plasmids.
Area of Science:
- Microbiology
- Genetics
- Gastroenterology
Background:
- R plasmids are known to confer antibiotic resistance to bacteria.
- The ability of bacterial strains to colonize the gastrointestinal tract is crucial for their persistence and potential pathogenicity.
- The influence of R plasmid origin on bacterial colonization dynamics within a host is not fully understood.
Purpose of the Study:
- To investigate how the origin of R plasmids affects the colonization ability of Escherichia coli in the mouse alimentary tract.
- To compare the colonization success of R plasmid-positive (R(+)) and R plasmid-negative (R(-)) E. coli strains.
Main Methods:
- Inoculation of streptomycin-treated mice with isogenic pairs of R(+) and R(-) E. coli strains.
- Enumeration of fecal E. coli strains to assess colonization levels.
- Utilizing R plasmids originating from a cryptic plasmid of the host E. coli strain for comparative analysis.
Main Results:
- E. coli strains carrying R plasmids not originating from the host showed colonization levels similar to or lower than their R(-) counterparts.
- These R(+) strains rapidly decreased in the fecal population.
- When R plasmids originated from the host's cryptic plasmid, the R(+) strain dominated the R(-) counterpart throughout the experiment.
Conclusions:
- The origin of R plasmids is a critical factor determining the colonization efficiency of Escherichia coli in the mouse alimentary tract.
- Host-derived R plasmids can enhance bacterial colonization, suggesting a co-evolutionary adaptation.
- These findings have implications for understanding bacterial persistence and the role of plasmids in host-microbe interactions.
