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Mutant RNA polymerase can reduce susceptibility to antibiotics via ppGpp-independent induction of a stringent-like response

BACKGROUND: Mutations in RNA polymerase (RNAP) can reduce susceptibility to ciprofloxacin in Escherichia coli, but the mechanism of transcriptional reprogramming responsible is unknown. Strains carrying ciprofloxacin-resistant (Cip(R)) rpoB mutations have reduced growth fitness and their impact on c...

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Autores principales: Brandis, Gerrit, Granström, Susanna, Leber, Anna T, Bartke, Katrin, Garoff, Linnéa, Cao, Sha, Huseby, Douglas L, Hughes, Diarmaid
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7879142/
https://www.ncbi.nlm.nih.gov/pubmed/33221850
http://dx.doi.org/10.1093/jac/dkaa469
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author Brandis, Gerrit
Granström, Susanna
Leber, Anna T
Bartke, Katrin
Garoff, Linnéa
Cao, Sha
Huseby, Douglas L
Hughes, Diarmaid
author_facet Brandis, Gerrit
Granström, Susanna
Leber, Anna T
Bartke, Katrin
Garoff, Linnéa
Cao, Sha
Huseby, Douglas L
Hughes, Diarmaid
author_sort Brandis, Gerrit
collection PubMed
description BACKGROUND: Mutations in RNA polymerase (RNAP) can reduce susceptibility to ciprofloxacin in Escherichia coli, but the mechanism of transcriptional reprogramming responsible is unknown. Strains carrying ciprofloxacin-resistant (Cip(R)) rpoB mutations have reduced growth fitness and their impact on clinical resistance development is unclear. OBJECTIVES: To assess the potential for Cip(R)rpoB mutations to contribute to resistance development by estimating the number of distinct alleles. To identify fitness-compensatory mutations that ameliorate the fitness costs of Cip(R)rpoB mutations. To understand how Cip(R)rpoB mutations reprogramme RNAP. METHODS: E. coli strains carrying five different Cip(R)rpoB alleles were evolved with selection for improved fitness and characterized for acquired mutations, relative fitness and MIC(Cip). The effects of dksA mutations and a ppGpp(0) background on growth and susceptibility phenotypes associated with Cip(R)rpoB alleles were determined. RESULTS: The number of distinct Cip(R)rpoB mutations was estimated to be >100. Mutations in RNAP genes and in dksA can compensate for the fitness cost of Cip(R)rpoB mutations. Deletion of dksA reduced the MIC(Cip) for strains carrying Cip(R)rpoB alleles. A ppGpp(0) phenotype had no effect on drug susceptibility. CONCLUSIONS: Cip(R)rpoB mutations induce an ppGpp-independent stringent-like response. Approximately half of the reduction in ciprofloxacin susceptibility is caused by an increased affinity of RNAP to DksA while the other half is independent of DksA. Stringent-like response activating mutations might be the most diverse class of mutations reducing susceptibility to antibiotics.
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spelling pubmed-78791422021-02-17 Mutant RNA polymerase can reduce susceptibility to antibiotics via ppGpp-independent induction of a stringent-like response Brandis, Gerrit Granström, Susanna Leber, Anna T Bartke, Katrin Garoff, Linnéa Cao, Sha Huseby, Douglas L Hughes, Diarmaid J Antimicrob Chemother Original Research BACKGROUND: Mutations in RNA polymerase (RNAP) can reduce susceptibility to ciprofloxacin in Escherichia coli, but the mechanism of transcriptional reprogramming responsible is unknown. Strains carrying ciprofloxacin-resistant (Cip(R)) rpoB mutations have reduced growth fitness and their impact on clinical resistance development is unclear. OBJECTIVES: To assess the potential for Cip(R)rpoB mutations to contribute to resistance development by estimating the number of distinct alleles. To identify fitness-compensatory mutations that ameliorate the fitness costs of Cip(R)rpoB mutations. To understand how Cip(R)rpoB mutations reprogramme RNAP. METHODS: E. coli strains carrying five different Cip(R)rpoB alleles were evolved with selection for improved fitness and characterized for acquired mutations, relative fitness and MIC(Cip). The effects of dksA mutations and a ppGpp(0) background on growth and susceptibility phenotypes associated with Cip(R)rpoB alleles were determined. RESULTS: The number of distinct Cip(R)rpoB mutations was estimated to be >100. Mutations in RNAP genes and in dksA can compensate for the fitness cost of Cip(R)rpoB mutations. Deletion of dksA reduced the MIC(Cip) for strains carrying Cip(R)rpoB alleles. A ppGpp(0) phenotype had no effect on drug susceptibility. CONCLUSIONS: Cip(R)rpoB mutations induce an ppGpp-independent stringent-like response. Approximately half of the reduction in ciprofloxacin susceptibility is caused by an increased affinity of RNAP to DksA while the other half is independent of DksA. Stringent-like response activating mutations might be the most diverse class of mutations reducing susceptibility to antibiotics. Oxford University Press 2020-11-21 /pmc/articles/PMC7879142/ /pubmed/33221850 http://dx.doi.org/10.1093/jac/dkaa469 Text en © The Author(s) 2020. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. http://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com
spellingShingle Original Research
Brandis, Gerrit
Granström, Susanna
Leber, Anna T
Bartke, Katrin
Garoff, Linnéa
Cao, Sha
Huseby, Douglas L
Hughes, Diarmaid
Mutant RNA polymerase can reduce susceptibility to antibiotics via ppGpp-independent induction of a stringent-like response
title Mutant RNA polymerase can reduce susceptibility to antibiotics via ppGpp-independent induction of a stringent-like response
title_full Mutant RNA polymerase can reduce susceptibility to antibiotics via ppGpp-independent induction of a stringent-like response
title_fullStr Mutant RNA polymerase can reduce susceptibility to antibiotics via ppGpp-independent induction of a stringent-like response
title_full_unstemmed Mutant RNA polymerase can reduce susceptibility to antibiotics via ppGpp-independent induction of a stringent-like response
title_short Mutant RNA polymerase can reduce susceptibility to antibiotics via ppGpp-independent induction of a stringent-like response
title_sort mutant rna polymerase can reduce susceptibility to antibiotics via ppgpp-independent induction of a stringent-like response
topic Original Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7879142/
https://www.ncbi.nlm.nih.gov/pubmed/33221850
http://dx.doi.org/10.1093/jac/dkaa469
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