High potency of sequential therapy with only beta-lactam antibiotics
- Kiel University, Germany
- University of Kiel, Germany
- Borstel Research Centre, Germany
Abstract
Evolutionary adaptation is a major source of antibiotic resistance in bacterial pathogens. Evolution-informed therapy aims to constrain resistance by accounting for bacterial evolvability. Sequential treatments with antibiotics that target different bacterial processes were previously shown to limit adaptation through genetic resistance trade-offs and negative hysteresis. Treatment with homogeneous sets of antibiotics is generally viewed to be disadvantageous, as it should rapidly lead to cross-resistance. We here challenged this assumption by determining the evolutionary response of Pseudomonas aeruginosa to experimental sequential treatments involving both heterogenous and homogeneous antibiotic sets. To our surprise, we found that fast switching between only β-lactam antibiotics resulted in increased extinction of bacterial populations. We demonstrate that extinction is favored by low rates of spontaneous resistance emergence and low levels of spontaneous cross-resistance among the antibiotics in sequence. The uncovered principles may help to guide the optimized use of available antibiotics in highly potent, evolution-informed treatment designs.
Data availability
Sequencing data have been deposited at NCBI under the BioProject number: PRJNA704789. All other data is provided in the supplementary source data files.
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Cellular hysteresis as a principle to maximize the efficacy of antibiotic therapy - Results on extinction frequencieshttps://doi.org/10.1073/pnas.1810004115.
Article and author information
Author details
Hinrich Schulenburg
Funding
Deutsche Forschungsgemeinschaft (SCHU 1415/12)
- Hinrich Schulenburg
Deutsche Forschungsgemeinschaft (EXC 2167-390884018)
- Stefan Niemann
- Hinrich Schulenburg
Deutsche Forschungsgemeinschaft (GRK 2501)
- Stefan Niemann
- Hinrich Schulenburg
Max-Planck-Gesellschaft (IMPRS Stipend)
- Aditi Batra
Max-Planck-Gesellschaft (Fellowship)
- Hinrich Schulenburg
Leibniz-Gemeinschaft (EvoLUNG)
- Stefan Niemann
- Hinrich Schulenburg
Deutsche Forschungsgemeinschaft (project 407495230)
- Sören Franzenburg
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2021, Batra et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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High potency of sequential therapy with only beta-lactam antibiotics
eLife 10:e68876.
https://doi.org/10.7554/eLife.68876
Further reading
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- Evolutionary Biology
- Epidemiology and Global Health
- Microbiology and Infectious Disease
- Genetics and Genomics
eLife is pleased to present a Special Issue to highlight recent advances in the growing and increasingly interdisciplinary field of evolutionary medicine.
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- Cell Biology
- Evolutionary Biology
Maintenance of rod-shape in bacterial cells depends on the actin-like protein MreB. Deletion of mreB from Pseudomonas fluorescens SBW25 results in viable spherical cells of variable volume and reduced fitness. Using a combination of time-resolved microscopy and biochemical assay of peptidoglycan synthesis, we show that reduced fitness is a consequence of perturbed cell size homeostasis that arises primarily from differential growth of daughter cells. A 1000-generation selection experiment resulted in rapid restoration of fitness with derived cells retaining spherical shape. Mutations in the peptidoglycan synthesis protein Pbp1A were identified as the main route for evolutionary rescue with genetic reconstructions demonstrating causality. Compensatory pbp1A mutations that targeted transpeptidase activity enhanced homogeneity of cell wall synthesis on lateral surfaces and restored cell size homeostasis. Mechanistic explanations require enhanced understanding of why deletion of mreB causes heterogeneity in cell wall synthesis. We conclude by presenting two testable hypotheses, one of which posits that heterogeneity stems from non-functional cell wall synthesis machinery, while the second posits that the machinery is functional, albeit stalled. Overall, our data provide support for the second hypothesis and draw attention to the importance of balance between transpeptidase and glycosyltransferase functions of peptidoglycan building enzymes for cell shape determination.
