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Quantification of Plasmid-Mediated Antibiotic Resistance in an Experimental Evolution Approach
Published on: December 14, 2019
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Plasmid carriage can limit bacteria-phage coevolution
Ellie Harrison1, Julie Truman2, Rosanna Wright3
1Department of Biology, University of York, York YO10 5DD, UK ellie.harrison@york.ac.uk.
Biology Letters
|August 14, 2015
Summary
Bacterial plasmids, like pQBR103, can limit coevolution with bacteriophages. Plasmid carriage in Pseudomonas fluorescens reduced bacterial phage resistance and phage infectivity, impacting bacterial evolution.
Area of Science:
- Microbiology
- Evolutionary Biology
- Genetics
Background:
- Bacteria-phage coevolution is a significant driver of bacterial population dynamics.
- Environmental and genetic factors influence the speed and nature of coevolutionary processes.
- Large conjugative plasmids can alter bacterial phenotypes and evolutionary trajectories.
Purpose of the Study:
- To investigate the impact of conjugative plasmid pQBR103 carriage on the coevolution between Pseudomonas fluorescens and its bacteriophage SBW25ϕ2.
- To determine if plasmid carriage affects the development of phage resistance in bacteria and infectivity in phages.
- To explore the role of mucoidy in bacterial adaptation during phage-host coevolution in the presence of plasmids.
Main Methods:
- Experimental evolution of Pseudomonas fluorescens with and without the conjugative plasmid pQBR103 in the presence of bacteriophage SBW25ϕ2.
- Quantification of bacterial phage resistance and phage infectivity over multiple coevolutionary cycles.
- Analysis of the costs associated with phage resistance mutations and the frequency of mucoid bacterial phenotypes.
Main Results:
- Plasmid carriage significantly limited bacteria-phage coevolution, resulting in lower phage resistance in bacteria and reduced infectivity in phages compared to plasmid-free populations.
- These effects were not attributable to increased costs of phage resistance mutations associated with plasmid carriage.
- The presence of phages and plasmids led to the evolution of high frequencies of mucoid bacterial colonies, which conferred weak partial resistance to the phage.
Conclusions:
- Conjugative plasmids can profoundly influence bacteria-phage coevolutionary dynamics.
- Plasmid carriage can dampen coevolutionary arms races by altering resistance/infectivity levels and promoting alternative resistance strategies like mucoidy.
- The evolutionary consequences of plasmid carriage extend beyond the direct effects of accessory genes, impacting host-microbe interactions and population evolution.
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