Conjugative plasmids enable the maintenance of low cost non-transmissible plasmids

Authored by Uta Berger, Martin Werisch, Thomas U Berendonk

Date Published: 2017

DOI: 10.1016/j.plasmid.2017.04.004

Sponsors: German Federal Ministry of Education and Research (BMBF)

Platforms: NetLogo

Model Documentation: ODD Flow charts

Model Code URLs: https://ars-els-cdn-com.ezproxy1.lib.asu.edu/content/image/1-s2.0-S0147619X16301160-mmc1.zip

Abstract

Some plasmids can be transferred by conjugation to other bacterial hosts. But almost half of the plasmids are non-transmissible. These plasmid types can only be transmitted to the daughter cells of their host after bacterial fission. Previous studies suggest that non-transmissible plasmids become extinct in the absence of selection of their encoded traits, as plasmid-free bacteria are more competitive. Here, we aim to identify mechanisms that enable non-transmissible plasmids to persist, even if they are not beneficial. For this purpose, an individual based model for plasmid population dynamics was set up and carefully tested for structural consistency and plausibility. Our results demonstrate that non-transmissible plasmids can be stably maintained in a population, even if they impose a substantial burden on their host cells growth. A prerequisite is the co-occurrence of an incompatible and costly conjugative plasmid type, which indirectly facilitates the preservation of the non transmissible type. We suggest that this constellation might be considered as a potential mechanism maintaining plasmids and associated antibiotic resistances. It should be investigated in upcoming laboratory experiments.

Tags

Evolution selection invasion kinetics mobility Protocol Biology Antibiotic-resistance Bacterial-populations Horizontal gene-transfer Horizontal gene transfer Transfer competence regulation Plasmid incompatibility Plasmid persistence Plasmid interaction Individual-based simulation model