Live to cheat another day: bacterial dormancy facilitates the social exploitation of beta-lactamases
File(s)
Accepted version
Published version
Author(s)
Medaney, F
Dimitriu, T
Ellis, RJ
Raymond, B
Type
Journal Article
Abstract
The breakdown of antibiotics by β-lactamases may be cooperative, since resistant cells can detoxify their environment and facilitate the growth of susceptible neighbours. However, previous studies of this phenomenon have used artificial bacterial vectors or engineered bacteria to increase the secretion of β-lactamases from cells. Here, we investigated whether a broad-spectrum β-lactamase gene carried by a naturally occurring plasmid (pCT) is cooperative under a range of conditions. In ordinary batch culture on solid media, there was little or no evidence that resistant bacteria could protect susceptible cells from ampicillin, although resistant colonies could locally detoxify this growth medium. However, when susceptible cells were inoculated at high densities, late-appearing phenotypically susceptible bacteria grew in the vicinity of resistant colonies. We infer that persisters, cells that have survived antibiotics by undergoing a period of dormancy, founded these satellite colonies. The number of persister colonies was positively correlated with the density of resistant colonies and increased as antibiotic concentrations decreased. We argue that detoxification can be cooperative under a limited range of conditions: if the toxins are bacteriostatic rather than bacteridical; or if susceptible cells invade communities after resistant bacteria; or if dormancy allows susceptible cells to avoid bactericides. Resistance and tolerance were previously thought to be independent solutions for surviving antibiotics. Here, we show that these are interacting strategies: the presence of bacteria adopting one solution can have substantial effects on the fitness of their neighbours.
Date Issued
2015-10-27
Date Acceptance
2015-07-08
Citation
ISME Journal, 2015, 10, pp.778-787
ISSN
1751-7362
Publisher
Nature Publishing Group
Start Page
778
End Page
787
Journal / Book Title
ISME Journal
Volume
10
Copyright Statement
This work is licensed under a Creative
Commons Attribution 4.0 International
License. The images or other third party material in
this article are included in the article’s Creative
Commons license, unless indicated otherwise in the
credit line; if the material is not included under the
Creative Commons license, users will need to obtain
permission from the license holder to reproduce the
material. To view a copy of this license, visit http://
creativecommons.org/licenses/by/4.0/
Commons Attribution 4.0 International
License. The images or other third party material in
this article are included in the article’s Creative
Commons license, unless indicated otherwise in the
credit line; if the material is not included under the
Creative Commons license, users will need to obtain
permission from the license holder to reproduce the
material. To view a copy of this license, visit http://
creativecommons.org/licenses/by/4.0/
License URL
Sponsor
Natural Environment Research Council [2006-2012]
Grant Number
NE/E012671/1
Subjects
Microbiology
06 Biological Sciences
10 Technology
05 Environmental Sciences
Publication Status
Published