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Chubiz LM. The Mar, Sox, and Rob Systems. EcoSal Plus 2023; 11:eesp00102022. [PMID: 37220096 DOI: 10.1128/ecosalplus.esp-0010-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 03/03/2023] [Indexed: 01/28/2024]
Abstract
Environments inhabited by Enterobacteriaceae are diverse and often stressful. This is particularly true for Escherichia coli and Salmonella during host association in the gastrointestinal systems of animals. There, E. coli and Salmonella must survive exposure to various antimicrobial compounds produced or ingested by their host. A myriad of changes to cellular physiology and metabolism are required to achieve this feat. A central regulatory network responsible for sensing and responding to intracellular chemical stressors like antibiotics are the Mar, Sox, and Rob systems found throughout the Enterobacteriaceae. Each of these distinct regulatory networks controls expression of an overlapping set of downstream genes whose collective effects result in increased resistance to a wide array of antimicrobial compounds. This collection of genes is known as the mar-sox-rob regulon. This review will provide an overview of the mar-sox-rob regulon and molecular architecture of the Mar, Sox, and Rob systems.
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Affiliation(s)
- Lon M Chubiz
- Department of Biology, University of Missouri-St. Louis, St. Louis, Missouri, USA
- Biochemistry and Biotechnology Program, University of Missouri-St. Louis, St. Louis, Missouri, USA
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2
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Wan Nur Ismah WAK, Takebayashi Y, Findlay J, Heesom KJ, Avison MB. Impact of OqxR loss of function on the envelope proteome of Klebsiella pneumoniae and susceptibility to antimicrobials. J Antimicrob Chemother 2019; 73:2990-2996. [PMID: 30053019 DOI: 10.1093/jac/dky293] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 06/25/2018] [Indexed: 11/15/2022] Open
Abstract
Background In Klebsiella pneumoniae, loss-of-function mutations in the transcriptional repressors RamR and OqxR both have an impact on the production of efflux pumps and porins relevant to antimicrobial efflux/entry. Objectives To define, in an otherwise isogenic background, the relative effects of OqxR and RamR loss-of-function mutations on envelope protein production, envelope permeability and antimicrobial susceptibility. We also investigated the clinical relevance of an OqxR loss-of-function mutation, particularly in the context of β-lactam susceptibility. Methods Envelope permeability was estimated using a fluorescent dye accumulation assay. Antimicrobial susceptibility was measured using disc testing. Total envelope protein production was quantified using LC-MS/MS proteomics and quantitative RT-PCR was used to measure transcript levels. Results Loss of RamR or OqxR reduced envelope permeability in K. pneumoniae by 45%-55% relative to the WT. RamR loss activated AcrAB efflux pump production ∼5-fold and this reduced β-lactam susceptibility, conferring ertapenem non-susceptibility even in the absence of a carbapenemase. In contrast, OqxR loss specifically activated OqxAB efflux pump production >10 000-fold. This reduced fluoroquinolone susceptibility but had little impact on β-lactam susceptibility even in the presence of a β-lactamase. Conclusions Whilst OqxR loss and RamR loss are both seen in K. pneumoniae clinical isolates, only RamR loss significantly stimulates AcrAB efflux pump production. This means that only RamR mutants have significantly reduced β-lactamase-mediated β-lactam susceptibility and therefore represent a greater clinical threat.
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Affiliation(s)
- Wan Ahmad Kamil Wan Nur Ismah
- School of Cellular & Molecular Medicine, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, UK
- Faculty of Biotechnology & Biomolecular Sciences, Universiti Putra Malaysia, Selangor Darul Ehsan, Malaysia
| | - Yuiko Takebayashi
- School of Cellular & Molecular Medicine, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, UK
| | - Jacqueline Findlay
- School of Cellular & Molecular Medicine, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, UK
| | - Kate J Heesom
- Bristol Proteomics Facility, University of Bristol, Bristol, UK
| | - Matthew B Avison
- School of Cellular & Molecular Medicine, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, UK
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3
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Dean CR, Barkan DT, Bermingham A, Blais J, Casey F, Casarez A, Colvin R, Fuller J, Jones AK, Li C, Lopez S, Metzger LE, Mostafavi M, Prathapam R, Rasper D, Reck F, Ruzin A, Shaul J, Shen X, Simmons RL, Skewes-Cox P, Takeoka KT, Tamrakar P, Uehara T, Wei JR. Mode of Action of the Monobactam LYS228 and Mechanisms Decreasing In Vitro Susceptibility in Escherichia coli and Klebsiella pneumoniae. Antimicrob Agents Chemother 2018; 62:e01200-18. [PMID: 30061293 PMCID: PMC6153799 DOI: 10.1128/aac.01200-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/25/2018] [Indexed: 12/14/2022] Open
Abstract
The monobactam scaffold is attractive for the development of new agents to treat infections caused by drug-resistant Gram-negative bacteria because it is stable to metallo-β-lactamases (MBLs). However, the clinically used monobactam aztreonam lacks stability to serine β-lactamases (SBLs) that are often coexpressed with MBLs. LYS228 is stable to MBLs and most SBLs. LYS228 bound purified Escherichia coli penicillin binding protein 3 (PBP3) similarly to aztreonam (derived acylation rate/equilibrium dissociation constant [k2/Kd ] of 367,504 s-1 M-1 and 409,229 s-1 M-1, respectively) according to stopped-flow fluorimetry. A gel-based assay showed that LYS228 bound mainly to E. coli PBP3, with weaker binding to PBP1a and PBP1b. Exposing E. coli cells to LYS228 caused filamentation consistent with impaired cell division. No single-step mutants were selected from 12 Enterobacteriaceae strains expressing different classes of β-lactamases at 8× the MIC of LYS228 (frequency, <2.5 × 10-9). At 4× the MIC, mutants were selected from 2 of 12 strains at frequencies of 1.8 × 10-7 and 4.2 × 10-9 LYS228 MICs were ≤2 μg/ml against all mutants. These frequencies compared favorably to those for meropenem and tigecycline. Mutations decreasing LYS228 susceptibility occurred in ramR and cpxA (Klebsiella pneumoniae) and baeS (E. coli and K. pneumoniae). Susceptibility of E. coli ATCC 25922 to LYS228 decreased 256-fold (MIC, 0.125 to 32 μg/ml) after 20 serial passages. Mutants accumulated mutations in ftsI (encoding the target, PBP3), baeR, acrD, envZ, sucB, and rfaI These results support the continued development of LYS228, which is currently undergoing phase II clinical trials for complicated intraabdominal infection and complicated urinary tract infection (registered at ClinicalTrials.gov under identifiers NCT03377426 and NCT03354754).
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Affiliation(s)
- Charles R Dean
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - David T Barkan
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Alun Bermingham
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Johanne Blais
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Fergal Casey
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Anthony Casarez
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Richard Colvin
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, USA
| | - John Fuller
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Adriana K Jones
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Cindy Li
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Sara Lopez
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Louis E Metzger
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Mina Mostafavi
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Ramadevi Prathapam
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Dita Rasper
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Folkert Reck
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Alexey Ruzin
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Jacob Shaul
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Xiaoyu Shen
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Robert L Simmons
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Peter Skewes-Cox
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Kenneth T Takeoka
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Pramila Tamrakar
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Tsuyoshi Uehara
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Jun-Rong Wei
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
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Jiménez-Castellanos JC, Wan Nur Ismah WAK, Takebayashi Y, Findlay J, Schneiders T, Heesom KJ, Avison MB. Envelope proteome changes driven by RamA overproduction in Klebsiella pneumoniae that enhance acquired β-lactam resistance. J Antimicrob Chemother 2018; 73:88-94. [PMID: 29029194 DOI: 10.1093/jac/dkx345] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 08/25/2017] [Indexed: 12/20/2022] Open
Abstract
Objectives In Klebsiella pneumoniae, overproduction of RamA results in reduced envelope permeability and reduced antimicrobial susceptibility but clinically relevant resistance is rarely observed. Here we have tested whether RamA overproduction can enhance acquired β-lactam resistance mechanisms in K. pneumoniae and have defined the envelope protein abundance changes upon RamA overproduction during growth in low and high osmolarity media. Methods Envelope permeability was estimated using a fluorescent dye accumulation assay. β-Lactam susceptibility was measured using disc testing. Total envelope protein production was quantified using LC-MS/MS proteomics and transcript levels were quantified using real-time RT-PCR. Results RamA overproduction enhanced β-lactamase-mediated β-lactam resistance, in some cases dramatically, without altering β-lactamase production. It increased production of efflux pumps and decreased OmpK35 porin production, though micF overexpression showed that OmpK35 reduction has little impact on envelope permeability. A survey of K. pneumoniae bloodstream isolates revealed ramA hyperexpression in 3 of 4 carbapenemase producers, 1 of 21 CTX-M producers and 2 of 19 strains not carrying CTX-M or carbapenemases. Conclusions Whilst RamA is not a key mediator of antibiotic resistance in K. pneumoniae on its own, it is potentially important for enhancing the spectrum of acquired β-lactamase-mediated β-lactam resistance. LC-MS/MS proteomics analysis has revealed that this enhancement is achieved predominantly through activation of efflux pump production.
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Affiliation(s)
| | - Wan Ahmad Kamil Wan Nur Ismah
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.,Faculty of Biotechnology & Biomolecular Sciences, Universiti Putra Malaysia, Selangor Darul Ehsan, Malaysia
| | - Yuiko Takebayashi
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Jacqueline Findlay
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Thamarai Schneiders
- Division of Infection and Pathway Medicine, University of Edinburgh, Edinburgh, UK
| | - Kate J Heesom
- University of Bristol Proteomics Facility, Bristol, UK
| | - Matthew B Avison
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
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Scavuzzi AML, Maciel MAV, de Melo HRL, Alves LC, Brayner FA, Lopes ACS. Occurrence of qnrB1 and qnrB12 genes, mutation in gyrA and ramR, and expression of efflux pumps in isolates of Klebsiella pneumoniae carriers of bla
KPC-2. J Med Microbiol 2017; 66:477-484. [DOI: 10.1099/jmm.0.000452] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Alexsandra Maria Lima Scavuzzi
- Centro de Pesquisas Aggeu Magalhães (CPqAM-Fiocruz), Recife-PE, Brazil
- Departamento de Medicina Tropical, Universidade Federal de Pernambuco (UFPE), 50.732-970, Recife-PE, Brazil
| | - Maria Amélia Vieira Maciel
- Departamento de Medicina Tropical, Universidade Federal de Pernambuco (UFPE), 50.732-970, Recife-PE, Brazil
| | - Heloísa Ramos Lacerda de Melo
- Departamento de Medicina Tropical, Universidade Federal de Pernambuco (UFPE), 50.732-970, Recife-PE, Brazil
- Departamento de Clínica Médica, Universidade Federal de Pernambuco (UFPE), 50.732-970, Recife-PE, Brazil
| | - Luiz Carlos Alves
- Centro de Pesquisas Aggeu Magalhães (CPqAM-Fiocruz), Recife-PE, Brazil
| | - Fábio André Brayner
- Departamento de Medicina Tropical, Universidade Federal de Pernambuco (UFPE), 50.732-970, Recife-PE, Brazil
- Centro de Pesquisas Aggeu Magalhães (CPqAM-Fiocruz), Recife-PE, Brazil
| | - Ana Catarina Souza Lopes
- Departamento de Medicina Tropical, Universidade Federal de Pernambuco (UFPE), 50.732-970, Recife-PE, Brazil
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Brem J, Cain R, Cahill S, McDonough MA, Clifton IJ, Jiménez-Castellanos JC, Avison MB, Spencer J, Fishwick CWG, Schofield CJ. Structural basis of metallo-β-lactamase, serine-β-lactamase and penicillin-binding protein inhibition by cyclic boronates. Nat Commun 2016; 7:12406. [PMID: 27499424 PMCID: PMC4979060 DOI: 10.1038/ncomms12406] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 06/29/2016] [Indexed: 12/24/2022] Open
Abstract
β-Lactamases enable resistance to almost all β-lactam antibiotics. Pioneering work revealed that acyclic boronic acids can act as 'transition state analogue' inhibitors of nucleophilic serine enzymes, including serine-β-lactamases. Here we report biochemical and biophysical analyses revealing that cyclic boronates potently inhibit both nucleophilic serine and zinc-dependent β-lactamases by a mechanism involving mimicking of the common tetrahedral intermediate. Cyclic boronates also potently inhibit the non-essential penicillin-binding protein PBP 5 by the same mechanism of action. The results open the way for development of dual action inhibitors effective against both serine- and metallo-β-lactamases, and which could also have antimicrobial activity through inhibition of PBPs.
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Affiliation(s)
- Jürgen Brem
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Ricky Cain
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
| | - Samuel Cahill
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Michael A. McDonough
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Ian J. Clifton
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | | | - Matthew B. Avison
- School of Cellular and Molecular Medicine, University of Bristol, Biomedical Sciences Building, Bristol BS8 1TD, UK
| | - James Spencer
- School of Cellular and Molecular Medicine, University of Bristol, Biomedical Sciences Building, Bristol BS8 1TD, UK
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Jiménez-Castellanos JC, Wan Ahmad Kamil WNI, Cheung CHP, Tobin MS, Brown J, Isaac SG, Heesom KJ, Schneiders T, Avison MB. Comparative effects of overproducing the AraC-type transcriptional regulators MarA, SoxS, RarA and RamA on antimicrobial drug susceptibility in Klebsiella pneumoniae. J Antimicrob Chemother 2016; 71:1820-5. [PMID: 27029850 DOI: 10.1093/jac/dkw088] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 02/26/2016] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES In Klebsiella pneumoniae, overproduction of RamA and RarA leads to increased MICs of various antibiotics; MarA and SoxS are predicted to perform a similar function. We have compared the relative effects of overproducing these four AraC-type regulators on envelope permeability (a combination of outer membrane permeability and efflux), efflux pump and porin production, and antibiotic susceptibility in K. pneumoniae. METHODS Regulators were overproduced using a pBAD expression vector. Antibiotic susceptibility was measured using disc testing. Envelope permeability was estimated using a fluorescent dye accumulation assay. Porin and efflux pump production was quantified using proteomics and validated using real-time quantitative RT-PCR. RESULTS Envelope permeability and antibiotic disc inhibition zone diameters both reduced during overproduction of RamA and to a lesser extent RarA or SoxS, but did not change following overproduction of MarA. These effects were associated with overproduction of the efflux pumps AcrAB (for RamA and SoxS) and OqxAB (for RamA and RarA) and the outer membrane protein TolC (for all regulators). Effects on porin production were strain specific. CONCLUSIONS RamA is the most potent regulator of antibiotic permeability in K. pneumoniae, followed by RarA then SoxS, with MarA having very little effect. This observed relative potency correlates well with the frequency at which these regulators are reportedly overproduced in clinical isolates.
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Affiliation(s)
| | - Wan Nur Ismah Wan Ahmad Kamil
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK Faculty of Biotechnology & Biomolecular Sciences, Universiti Putra Malaysia, Selangor Darul Ehsan, Malaysia
| | | | - Maryann S Tobin
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - James Brown
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Sophie G Isaac
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Kate J Heesom
- Bristol University Proteomics Facility, University of Bristol, Bristol, UK
| | - Thamarai Schneiders
- Division of Infection and Pathway Medicine, University of Edinburgh, Edinburgh, UK
| | - Matthew B Avison
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
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