Abstract
Background: Many soil-inhabiting bacteria are known to produce secondary metabolites that can suppress microorganisms
competing for the same resources. The production of antimicrobial compounds is expected to incur fitness costs for the
producing bacteria. Such costs form the basis for models on the co-existence of antibiotic-producing and non-antibiotic
producing strains. However, so far studies quantifying the costs of antibiotic production by bacteria are scarce. The current
study reports on possible costs, for antibiotic production by Pseudomonas fluorescens Pf0-1, a soil bacterium that is induced
to produce a broad-spectrum antibiotic when it is confronted with non-related bacterial competitors or supernatants of
their cultures.
Methodology and Principal Findings: We measured the possible cost of antibiotic production for Pseudomonas fluorescens
Pf0-1 by monitoring changes in growth rate with and without induction of antibiotic production by supernatant of a
bacterial competitor, namely Pedobacter sp.. Experiments were performed in liquid as well as on semi-solid media under
nutrient-limited conditions that are expected to most clearly reveal fitness costs. Our results did not reveal any significant
costs for production of antibiotics by Pseudomonas fluorescens Pf0-1. Comparison of growth rates of the antibioticproducing
wild-type cells with those of non-antibiotic producing mutants did not reveal costs of antibiotic production
either.
Significance: Based on our findings we propose that the facultative production of antibiotics might not be selected to
mitigate metabolic costs, but instead might be advantageous because it limits the risk of competitors evolving resistance, or
even the risk of competitors feeding on the compounds produced.
| Original language | English |
|---|---|
| Article number | e27266 |
| Journal | PLoS One |
| Volume | 6 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - 2011 |