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Belagal P. Genetic and molecular characterization of fit95 mutation of Escherichia coli: evidence that fit95 is an allele of pheT. Arch Microbiol 2024; 206:414. [PMID: 39316172 DOI: 10.1007/s00203-024-04127-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2024] [Revised: 08/25/2024] [Accepted: 09/02/2024] [Indexed: 09/25/2024]
Abstract
The originally identified transcription-defective fitA76 temperature-sensitive (Ts) mutation defined an allele of pheS. Both fitA/pheS and fitB/pheT were previously proposed to function as transcription factors. Sequencing pheS region of the fitA76 mutant revealed the same G293→A293 transition found in the translation-defective pheS5 mutant. It was subsequently found that fitA76 harbored a second mutation (fit95) in addition to pheS5 mutation. The fit95 was found to be Ts on -salt media but was found unstable. In this investigation, genetic, physiological and molecular characterization of the fit95 mutation was carried out. The fit95 was genetically re-separated from the pheS5 mutation present in the fitA76 mutant and the same was subsequently mobilized into multiple genetic backgrounds to study its phenotypic modulations by altering the medium and supplements. Based on genetic studies, the unstable -salt Ts phenotype of the fit95 could be stabilized by the presence of rpoB201 mutation. Addition of glucose enhanced Ts phenotype in the presence of rpoB201 mutation, but citrate completely alleviated the Ts phenotype. Further, by series of complementation analyses and molecular cloning, the identity of fit95 was revealed as pheT gene which is part of pheST operon.
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Affiliation(s)
- Praveen Belagal
- Department of Molecular Biology, School of Biological Sciences, Madurai Kamaraj University, Madurai, 625 021, India.
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2
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Zeden MS. mSphere of Influence: Targeting bacterial signaling and metabolism to overcome antimicrobial resistance. mSphere 2024; 9:e0063223. [PMID: 38305167 PMCID: PMC10900877 DOI: 10.1128/msphere.00632-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024] Open
Abstract
Dr Merve Suzan Zeden works in the field of molecular bacteriology and antibiotic resistance. In this mSphere of Influence article, she reflects on how three papers, entitled "c-di-AMP modulates Listeria monocytogenes central metabolism to regulate growth, antibiotic resistance and osmoregulation," "Amino acid catabolism in Staphylococcus aureus and the function of carbon catabolite repression," and "Evolving MRSA: high-level β-lactam resistance in Staphylococcus aureus is associated with RNA polymerase alterations and fine tuning of gene expression," made an impact on her work on bacterial metabolism and antimicrobial resistance and how it shaped her research in understanding the link in between.
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Affiliation(s)
- Merve S Zeden
- School of Biological and Chemical Sciences, College of Science and Engineering, University of Galway, Galway, Ireland
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3
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Choudhury A, Gachet B, Dixit Z, Faure R, Gill RT, Tenaillon O. Deep mutational scanning reveals the molecular determinants of RNA polymerase-mediated adaptation and tradeoffs. Nat Commun 2023; 14:6319. [PMID: 37813857 PMCID: PMC10562459 DOI: 10.1038/s41467-023-41882-7] [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: 02/23/2023] [Accepted: 09/21/2023] [Indexed: 10/11/2023] Open
Abstract
RNA polymerase (RNAP) is emblematic of complex biological systems that control multiple traits involving trade-offs such as growth versus maintenance. Laboratory evolution has revealed that mutations in RNAP subunits, including RpoB, are frequently selected. However, we lack a systems view of how mutations alter the RNAP molecular functions to promote adaptation. We, therefore, measured the fitness of thousands of mutations within a region of rpoB under multiple conditions and genetic backgrounds, to find that adaptive mutations cluster in two modules. Mutations in one module favor growth over maintenance through a partial loss of an interaction associated with faster elongation. Mutations in the other favor maintenance over growth through a destabilized RNAP-DNA complex. The two molecular handles capture the versatile RNAP-mediated adaptations. Combining both interaction losses simultaneously improved maintenance and growth, challenging the idea that growth-maintenance tradeoff resorts only from limited resources, and revealing how compensatory evolution operates within RNAP.
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Affiliation(s)
- Alaksh Choudhury
- Université de Paris Cité, INSERM, IAME, UMR 1137, 75018, Paris, France.
- Laboratoire Biophysique et Évolution (LBE), UMR Chimie Biologie Innovation 8231, ESPCI Paris, Université PSL, CNRS, 75005, Paris, France.
| | - Benoit Gachet
- Université de Paris Cité, INSERM, IAME, UMR 1137, 75018, Paris, France
| | - Zoya Dixit
- Université de Paris Cité, INSERM, IAME, UMR 1137, 75018, Paris, France
- Université de Paris Cité, INSERM, CNRS, Institut Cochin, UMR 1016, 75014, Paris, France
| | - Roland Faure
- Université de Paris Cité, INSERM, IAME, UMR 1137, 75018, Paris, France
- Université de Rennes, INRIA RBA, CNRS UMR 6074, Rennes, France
- Service Evolution Biologique et Ecologie, Université libre de Bruxelles (ULB), 1050, Brussels, Belgium
| | - Ryan T Gill
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado-Boulder, Boulder, CO, 80309-0027, USA
- Novo Nordisk Foundation, Denmark Technical University, 2800 Kgs, Lyngby, Denmark
| | - Olivier Tenaillon
- Université de Paris Cité, INSERM, IAME, UMR 1137, 75018, Paris, France.
- Université de Paris Cité, INSERM, CNRS, Institut Cochin, UMR 1016, 75014, Paris, France.
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Vanacker M, Lenuzza N, Rasigade JP. The fitness cost of horizontally transferred and mutational antimicrobial resistance in Escherichia coli. Front Microbiol 2023; 14:1186920. [PMID: 37455716 PMCID: PMC10348881 DOI: 10.3389/fmicb.2023.1186920] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 06/09/2023] [Indexed: 07/18/2023] Open
Abstract
Antimicrobial resistance (AMR) in bacteria implies a tradeoff between the benefit of resistance under antimicrobial selection pressure and the incurred fitness cost in the absence of antimicrobials. The fitness cost of a resistance determinant is expected to depend on its genetic support, such as a chromosomal mutation or a plasmid acquisition, and on its impact on cell metabolism, such as an alteration in an essential metabolic pathway or the production of a new enzyme. To provide a global picture of the factors that influence AMR fitness cost, we conducted a systematic review and meta-analysis focused on a single species, Escherichia coli. By combining results from 46 high-quality studies in a multilevel meta-analysis framework, we find that the fitness cost of AMR is smaller when provided by horizontally transferable genes such as those encoding beta-lactamases, compared to mutations in core genes such as those involved in fluoroquinolone and rifampicin resistance. We observe that the accumulation of acquired AMR genes imposes a much smaller burden on the host cell than the accumulation of AMR mutations, and we provide quantitative estimates of the additional cost of a new gene or mutation. These findings highlight that gene acquisition is more efficient than the accumulation of mutations to evolve multidrug resistance, which can contribute to the observed dominance of horizontally transferred genes in the current AMR epidemic.
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Affiliation(s)
- Marie Vanacker
- CIRI, Centre International de Recherche en Infectiologie, Université de Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Natacha Lenuzza
- CIRI, Centre International de Recherche en Infectiologie, Université de Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Jean-Philippe Rasigade
- CIRI, Centre International de Recherche en Infectiologie, Université de Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
- Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
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Vázquez X, Fernández J, Bances M, Lumbreras P, Alkorta M, Hernáez S, Prieto E, de la Iglesia P, de Toro M, Rodicio MR, Rodicio R. Genomic Analysis of Ciprofloxacin-Resistant Salmonella enterica Serovar Kentucky ST198 From Spanish Hospitals. Front Microbiol 2021; 12:720449. [PMID: 34675895 PMCID: PMC8525328 DOI: 10.3389/fmicb.2021.720449] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 09/13/2021] [Indexed: 11/17/2022] Open
Abstract
Salmonella enterica serovar Kentucky (S. Kentucky) with sequence type (ST) 198 and highly resistant to ciprofloxacin (ST198-CipR) has emerged as a global MDR clone, posing a threat to public health. In the present study, whole genome sequencing (WGS) was applied to characterize all CipRS. Kentucky detected in five Spanish hospitals during 2009–2018. All CipR isolates (n = 13) were ST198 and carried point mutations in the quinolone resistance-determining regions (QRDRs) of both gyrA (resulting in Ser83Phe and Asp87Gly, Asp87Asn, or Asp87Tyr substitutions in GyrA) and parC (with Thr57Ser and Ser80Ile substitutions in ParC). Resistances to other antibiotics (ampicillin, chloramphenicol, gentamicin, streptomycin, sulfonamides, and tetracycline), mediated by the blaTEM–1B, catA1, aacA5, aadA7, strA, strB, sul1, and tet(A) genes, and arranged in different combinations, were also observed. Analysis of the genetic environment of the latter resistance genes revealed the presence of multiple variants of SGI1 (Salmonella genomic island 1)-K and SGI1-P, where all these resistance genes except catA1 were placed. IS26 elements, found at multiple locations within the SGI1 variants, have probably played a crucial role in their generation. Despite the wide diversity of SGI1-K- and SGI1-P-like structures, phylogenetic analysis revealed a close relationship between isolates from different hospitals, which were separated by a minimum of two and a maximum of 160 single nucleotide polymorphisms. Considering that S. enterica isolates resistant to fluoroquinolones belong to the high priority list of antibiotic-resistant bacteria compiled by the World Health Organization, continuous surveillance of the S. Kentucky ST198-CIPR clone is required.
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Affiliation(s)
- Xenia Vázquez
- Área de Microbiología, Departamento de Biología Funcional, Universidad de Oviedo (UO), Oviedo, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Javier Fernández
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain.,Servicio de Microbiología, Hospital Universitario Central de Asturias (HUCA), Oviedo, Spain.,Research and Innovation, Artificial Intelligence and Statistical Department, Pragmatech AI Solutions, Oviedo, Spain
| | - Margarita Bances
- Laboratorio de Salud Pública (LSP) del Principado de Asturias, Dirección General de Salud Pública, Oviedo, Spain
| | - Pilar Lumbreras
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Miriam Alkorta
- Servicio de Microbiología, Hospital Universitario Donostia (HUD)-IIS Biodonostia, San Sebastián, Spain
| | - Silvia Hernáez
- Servicio de Microbiología, Hospital Universitario de Álava (HUA), Vitoria-Gasteiz, Spain
| | - Elizabeth Prieto
- Servicio de Microbiología, Hospital Universitario San Agustín, Avilés, Spain
| | | | - María de Toro
- Plataforma de Genómica y Bioinformática, Centro de Investigación Biomédica de La Rioja (CIBIR), Logroño, Spain
| | - M Rosario Rodicio
- Área de Microbiología, Departamento de Biología Funcional, Universidad de Oviedo (UO), Oviedo, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Rosaura Rodicio
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain.,Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo (UO), Oviedo, Spain
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Brandis G, Gockel J, Garoff L, Guy L, Hughes D. Expression of the qepA1 gene is induced under antibiotic exposure. J Antimicrob Chemother 2021; 76:1433-1440. [PMID: 33608713 PMCID: PMC8120332 DOI: 10.1093/jac/dkab045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 01/28/2021] [Indexed: 11/13/2022] Open
Abstract
Background The qepA1 gene encodes an efflux pump that reduces susceptibility to ciprofloxacin. Little is known about the regulation of qepA1 expression. Objectives To assess the potential role of ciprofloxacin and other antibiotics in the regulation of qepA1 gene expression. To identify the promoter that drives qepA1 expression and other factors involved in expression regulation. To assess whether the identified features are universal among qepA alleles. Methods A translational qepA1-yfp fusion under the control of the qepA1 upstream region was cloned into the Escherichia coli chromosome. Expression of the fusion protein was measured in the presence of various antibiotics. Deletions within the upstream region were introduced to identify regions involved in gene expression and regulation. The qepA1 coding sequence and upstream region were compared with all available qepA sequences. Results Cellular stress caused by the presence of various antibiotics can induce qepA1 expression. The qepA1 gene is fused to a class I integron and gene expression is driven by the Pc promoter within the integrase gene. A segment within the integron belonging to a truncated dfrB4 gene is essential for the regulation of qepA1 expression. This genetic context is universal among all sequenced qepA alleles. Conclusions The fusion of the qepA1 gene to a class I integron has created a novel regulatory unit that enables qepA1 expression to be under the control of antibiotic exposure. This setup mitigates potential negative effects of QepA1 production on bacterial fitness by restricting high-level expression to environmental conditions in which QepA1 is beneficial.
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Affiliation(s)
- Gerrit Brandis
- Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Box 582, Uppsala, Sweden
| | - Jonas Gockel
- Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Box 582, Uppsala, Sweden
| | - Linnéa Garoff
- Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Box 582, Uppsala, Sweden
| | - Lionel Guy
- Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Box 582, Uppsala, Sweden
| | - Diarmaid Hughes
- Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Box 582, Uppsala, Sweden
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