1
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Madden DE, Baird T, Bell SC, McCarthy KL, Price EP, Sarovich DS. Keeping up with the pathogens: improved antimicrobial resistance detection and prediction from Pseudomonas aeruginosa genomes. Genome Med 2024; 16:78. [PMID: 38849863 PMCID: PMC11157771 DOI: 10.1186/s13073-024-01346-z] [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: 10/29/2023] [Accepted: 05/20/2024] [Indexed: 06/09/2024] Open
Abstract
BACKGROUND Antimicrobial resistance (AMR) is an intensifying threat that requires urgent mitigation to avoid a post-antibiotic era. Pseudomonas aeruginosa represents one of the greatest AMR concerns due to increasing multi- and pan-drug resistance rates. Shotgun sequencing is gaining traction for in silico AMR profiling due to its unambiguity and transferability; however, accurate and comprehensive AMR prediction from P. aeruginosa genomes remains an unsolved problem. METHODS We first curated the most comprehensive database yet of known P. aeruginosa AMR variants. Next, we performed comparative genomics and microbial genome-wide association study analysis across a Global isolate Dataset (n = 1877) with paired antimicrobial phenotype and genomic data to identify novel AMR variants. Finally, the performance of our P. aeruginosa AMR database, implemented in our AMR detection and prediction tool, ARDaP, was compared with three previously published in silico AMR gene detection or phenotype prediction tools-abritAMR, AMRFinderPlus, ResFinder-across both the Global Dataset and an analysis-naïve Validation Dataset (n = 102). RESULTS Our AMR database comprises 3639 mobile AMR genes and 728 chromosomal variants, including 75 previously unreported chromosomal AMR variants, 10 variants associated with unusual antimicrobial susceptibility, and 281 chromosomal variants that we show are unlikely to confer AMR. Our pipeline achieved a genotype-phenotype balanced accuracy (bACC) of 85% and 81% across 10 clinically relevant antibiotics when tested against the Global and Validation Datasets, respectively, vs. just 56% and 54% with abritAMR, 58% and 54% with AMRFinderPlus, and 60% and 53% with ResFinder. ARDaP's superior performance was predominantly due to the inclusion of chromosomal AMR variants, which are generally not identified with most AMR identification tools. CONCLUSIONS Our ARDaP software and associated AMR variant database provides an accurate tool for predicting AMR phenotypes in P. aeruginosa, far surpassing the performance of current tools. Implementation of ARDaP for routine AMR prediction from P. aeruginosa genomes and metagenomes will improve AMR identification, addressing a critical facet in combatting this treatment-refractory pathogen. However, knowledge gaps remain in our understanding of the P. aeruginosa resistome, particularly the basis of colistin AMR.
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Affiliation(s)
- Danielle E Madden
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
| | - Timothy Baird
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
- Respiratory Department, Sunshine Coast University Hospital, Birtinya, Queensland, Australia
| | - Scott C Bell
- Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Chermside, Queensland, Australia
- Children's Health Research Centre, Faculty of Medicine, The University of Queensland, South Brisbane, Queensland, Australia
| | - Kate L McCarthy
- University of Queensland Medical School, Herston, QLD, Australia
- Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
| | - Erin P Price
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
| | - Derek S Sarovich
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, QLD, Australia.
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia.
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2
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Oliver A, Rojo-Molinero E, Arca-Suarez J, Beşli Y, Bogaerts P, Cantón R, Cimen C, Croughs PD, Denis O, Giske CG, Graells T, Daniel Huang TD, Iorga BI, Karatuna O, Kocsis B, Kronenberg A, López-Causapé C, Malhotra-Kumar S, Martínez LM, Mazzariol A, Meyer S, Naas T, Notermans DW, Oteo-Iglesias J, Pedersen T, Pirš M, Poeta P, Poirel L, Pournaras S, Sundsfjord A, Szabó D, Tambić-Andrašević A, Vatcheva-Dobrevska R, Vitkauskienė A, Jeannot K. Pseudomonasaeruginosa antimicrobial susceptibility profiles, resistance mechanisms and international clonal lineages: update from ESGARS-ESCMID/ISARPAE Group. Clin Microbiol Infect 2024; 30:469-480. [PMID: 38160753 DOI: 10.1016/j.cmi.2023.12.026] [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: 10/13/2023] [Revised: 12/18/2023] [Accepted: 12/25/2023] [Indexed: 01/03/2024]
Abstract
SCOPE Pseudomonas aeruginosa, a ubiquitous opportunistic pathogen considered one of the paradigms of antimicrobial resistance, is among the main causes of hospital-acquired and chronic infections associated with significant morbidity and mortality. This growing threat results from the extraordinary capacity of P. aeruginosa to develop antimicrobial resistance through chromosomal mutations, the increasing prevalence of transferable resistance determinants (such as the carbapenemases and the extended-spectrum β-lactamases), and the global expansion of epidemic lineages. The general objective of this initiative is to provide a comprehensive update of P. aeruginosa resistance mechanisms, especially for the extensively drug-resistant (XDR)/difficult-to-treat resistance (DTR) international high-risk epidemic lineages, and how the recently approved β-lactams and β-lactam/β-lactamase inhibitor combinations may affect resistance mechanisms and the definition of susceptibility profiles. METHODS To address this challenge, the European Study Group for Antimicrobial Resistance Surveillance (ESGARS) from the European Society of Clinical Microbiology and Infectious Diseases launched the 'Improving Surveillance of Antibiotic-Resistant Pseudomonas aeruginosa in Europe (ISARPAE)' initiative in 2022, supported by the Joint programming initiative on antimicrobial resistance network call and included a panel of over 40 researchers from 18 European Countries. Thus, a ESGARS-ISARPAE position paper was designed and the final version agreed after four rounds of revision and discussion by all panel members. QUESTIONS ADDRESSED IN THE POSITION PAPER To provide an update on (a) the emerging resistance mechanisms to classical and novel anti-pseudomonal agents, with a particular focus on β-lactams, (b) the susceptibility profiles associated with the most relevant β-lactam resistance mechanisms, (c) the impact of the novel agents and resistance mechanisms on the definitions of resistance profiles, and (d) the globally expanding XDR/DTR high-risk lineages and their association with transferable resistance mechanisms. IMPLICATION The evidence presented herein can be used for coordinated epidemiological surveillance and decision making at the European and global level.
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Affiliation(s)
- Antonio Oliver
- Servicio de Microbiología, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain; CIBER de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain.
| | - Estrella Rojo-Molinero
- Servicio de Microbiología, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain; CIBER de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Jorge Arca-Suarez
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain; Servicio de Microbiología and Instituto de Investigación Biomédica A Coruña (INIBIC), Complexo Hospitalario Universitario A Coruña, A Coruña, Spain
| | - Yeşim Beşli
- Department of Medical Microbiology, Amerikan Hastanesi, Istanbul, Turkey
| | - Pierre Bogaerts
- National Center for Antimicrobial Resistance in Gram, CHU UCL Namur, Yvoir, Belgium
| | - Rafael Cantón
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain; Servicio de Microbiología, Hospital Universitario Ramón y Cajal-IRYCIS, Madrid, Spain
| | - Cansu Cimen
- Institute for Medical Microbiology and Virology, University of Oldenburg, Oldenburg, Germany; Department of Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Peter D Croughs
- Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Olivier Denis
- Department of Microbiology, CHU Namur Site-Godinne, Université Catholique de Louvain, Yvoir, Belgium; Ecole de Santé Publique, Université Libre de Bruxelles, Brussels, Belgium
| | - Christian G Giske
- Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden; Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Solna, Stockholm, Sweden
| | - Tíscar Graells
- Department of Neurobiology, Care Sciences and Society (NVS), Division of Family Medicine and Primary Care, Karolinska Institutet, Huddinge, Stockholm, Sweden
| | - Te-Din Daniel Huang
- National Center for Antimicrobial Resistance in Gram, CHU UCL Namur, Yvoir, Belgium
| | - Bogdan I Iorga
- CNRS, Institut de Chimie des Substances Naturelles, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Onur Karatuna
- EUCAST Development Laboratory, Clinical Microbiology, Central Hospital, Växjö, Sweden
| | - Béla Kocsis
- Institute of Medical Microbiology, Semmelweis University, Budapest, Hungary
| | - Andreas Kronenberg
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Carla López-Causapé
- Servicio de Microbiología, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain; CIBER de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Surbhi Malhotra-Kumar
- Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - Luis Martínez Martínez
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain; Unidad de Microbiología, Hospital Universitario Reina Sofía, Departamento de Química Agrícola, Edafología y Microbiología, Universidad de Córdoba, e Instituto Maimonides de Investigación Biomédica de Córdoba (IMIBIC), Spain
| | - Annarita Mazzariol
- Microbiology and Virology Section, Department of Diagnostic and Public Health, University of Verona, Verona, Italy
| | - Sylvain Meyer
- INSERM UMR 1092 and Université of Limoges, Limoges, France
| | - Thierry Naas
- Laboratoire Associé du Centre National de Référence de la Résistance aux Antibiotiques: Entérobactéries Résistantes aux Carbapénèmes, Le Kremlin-Bicêtre, France; Équipe INSERM ReSIST, Faculté de Médecine, Université Paris-Saclay, Paris, France
| | - Daan W Notermans
- Centre for Infectious Disease Control. National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Jesús Oteo-Iglesias
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain; Reference and Research Laboratory in Resistance to Antibiotics and Infections Related to Healthcare, National Centre for Microbiology, Instituto de Salud Carlos III, Madrid, Spain
| | - Torunn Pedersen
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Mateja Pirš
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Patricia Poeta
- MicroART-Microbiology and Antibiotic Resistance Team, Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal; Associated Laboratory for Green Chemistry (LAQV-REQUIMTE), University NOVA of Lisboa, Lisboa, Portugal; Veterinary and Animal Research Centre (CECAV), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal; University of Trás-os-Montes and Alto Douro, Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Vila Real, Portugal
| | - Laurent Poirel
- Emerging Antibiotic Resistance Unit, Medical and Molecular Microbiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland; University of Fribourg, Swiss National Reference Center for Emerging Antibiotic Resistance, Fribourg, Switzerland
| | - Spyros Pournaras
- Laboratory of Clinical Microbiology, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Arnfinn Sundsfjord
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway; Research Group on Host-Microbe Interactions, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Dora Szabó
- Institute of Medical Microbiology, Semmelweis University, Budapest, Hungary; Human Microbiota Study Group, Semmelweis University-Eötvös Lóránd Research Network, Budapest, Hungary
| | - Arjana Tambić-Andrašević
- Department of Clinical Microbiology, University Hospital for Infectious Diseases, Zagreb, Croatia; School of Dental Medicine, University of Zagreb, Zagreb, Croatia
| | | | - Astra Vitkauskienė
- Department of Laboratory Medicine, Faculty of Medicine, Medical Academy, Lithuanian University of Health Science, Kaunas, Lithuania
| | - Katy Jeannot
- Laboratoire de Bactériologie, Centre Hospitalier Universitaire de Besançon, Besançon, France; Laboratoire associé du Centre National de Référence de la Résistance aux Antibiotiques, Centre Hospitalier Universitaire de Besançon, Besançon, France; Chrono-environnement UMR 6249, CNRS, Université Franche-Comté, Besançon, France
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3
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Sanz-García F, Laborda P, Ochoa-Sánchez LE, Martínez JL, Hernando-Amado S. The Pseudomonas aeruginosa Resistome: Permanent and Transient Antibiotic Resistance, an Overview. Methods Mol Biol 2024; 2721:85-102. [PMID: 37819517 DOI: 10.1007/978-1-0716-3473-8_7] [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: 10/13/2023]
Abstract
One of the most concerning characteristics of Pseudomonas aeruginosa is its low susceptibility to several antibiotics of common use in clinics, as well as its facility to acquire increased resistance levels. Consequently, the study of the antibiotic resistance mechanisms of this bacterium is of relevance for human health. For such a study, different types of resistance should be distinguished. The intrinsic resistome is composed of a set of genes, present in the core genome of P. aeruginosa, which contributes to its characteristic, species-specific, phenotype of susceptibility to antibiotics. Acquired resistance refers to those genetic events, such as the acquisition of mutations or antibiotic resistance genes that reduce antibiotic susceptibility. Finally, antibiotic resistance can be transiently acquired in the presence of specific compounds or under some growing conditions. The current article provides information on methods currently used to analyze intrinsic, mutation-driven, and transient antibiotic resistance in P. aeruginosa.
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Affiliation(s)
| | - Pablo Laborda
- Centro Nacional de Biotecnología, CSIC, Madrid, Spain
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4
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Simpson M, Harding CJ, Czekster RM, Remmel L, Bode BE, Czekster CM. Unveiling the Catalytic Mechanism of a Processive Metalloaminopeptidase. Biochemistry 2023; 62:3188-3205. [PMID: 37924287 PMCID: PMC10666288 DOI: 10.1021/acs.biochem.3c00420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 10/11/2023] [Accepted: 10/11/2023] [Indexed: 11/06/2023]
Abstract
Intracellular leucine aminopeptidases (PepA) are metalloproteases from the family M17. These enzymes catalyze peptide bond cleavage, removing N-terminal residues from peptide and protein substrates, with consequences for protein homeostasis and quality control. While general mechanistic studies using model substrates have been conducted on PepA enzymes from various organisms, specific information about their substrate preferences and promiscuity, choice of metal, activation mechanisms, and the steps that limit steady-state turnover remain unexplored. Here, we dissected the catalytic and chemical mechanisms of PaPepA: a leucine aminopeptidase from Pseudomonas aeruginosa. Cleavage assays using peptides and small-molecule substrate mimics allowed us to propose a mechanism for catalysis. Steady-state and pre-steady-state kinetics, pH rate profiles, solvent kinetic isotope effects, and biophysical techniques were used to evaluate metal binding and activation. This revealed that metal binding to a tight affinity site is insufficient for enzyme activity; binding to a weaker affinity site is essential for catalysis. Progress curves for peptide hydrolysis and crystal structures of free and inhibitor-bound PaPepA revealed that PaPepA cleaves peptide substrates in a processive manner. We propose three distinct modes for activity regulation: tight packing of PaPepA in a hexameric assembly controls substrate length and reaction processivity; the product leucine acts as an inhibitor, and the high concentration of metal ions required for activation limits catalytic turnover. Our work uncovers catalysis by a metalloaminopeptidase, revealing the intricacies of metal activation and substrate selection. This will pave the way for a deeper understanding of metalloenzymes and processive peptidases/proteases.
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Affiliation(s)
- Martha
Clementine Simpson
- School
of Biology, University of St Andrews, North Haugh, Biomolecular Sciences
Building, KY16 9ST, Saint Andrews, United Kingdom
| | - Christopher John Harding
- School
of Biology, University of St Andrews, North Haugh, Biomolecular Sciences
Building, KY16 9ST, Saint Andrews, United Kingdom
| | - Ricardo Melo Czekster
- School
of Computer Science and Digital Technologies, Department of Software
Engineering and Cybersecurity, Aston University, B4 7ET, Birmingham,United Kingdom
| | - Laura Remmel
- School
of Chemistry, University of St Andrews, North Haugh, Purdie Building, KY16 9ST, Saint Andrews , United Kingdom
| | - Bela E. Bode
- School
of Chemistry, University of St Andrews, North Haugh, Purdie Building, KY16 9ST, Saint Andrews , United Kingdom
| | - Clarissa Melo Czekster
- School
of Biology, University of St Andrews, North Haugh, Biomolecular Sciences
Building, KY16 9ST, Saint Andrews, United Kingdom
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5
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Tian ZX, Wang YP. Identification of cpxS mutational resistome in Pseudomonas aeruginosa. Antimicrob Agents Chemother 2023; 67:e0092123. [PMID: 37800959 PMCID: PMC10648845 DOI: 10.1128/aac.00921-23] [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: 07/14/2023] [Accepted: 08/08/2023] [Indexed: 10/07/2023] Open
Abstract
Pseudomonas aeruginosa easily produces drug-resistant mutants. A large number of mutational resistome genes exist in the genome of P. aeruginosa. In this study, whole genome sequencing analysis of a multidrug-resistant P. aeruginosa strain isolated by in vitro antibiotic treatment showed a mutation in the cpxS gene. Random mutagenesis of cpxS was conducted and introduced into the PA14ΔcpxS strain. Numerous CpxS mutants, including 14 different single amino acid substitutions, were identified, which led to reduced antibiotic susceptibility. Moreover, some of them were also present in the published genomes of P. aeruginosa isolates. Around cpxS, a gene coding for a putative sensor kinase, the nearest gene coding for a response regulator is cpxR in the genome of P. aeruginosa. Deletion of cpxR restored antibiotic susceptibility in the above cpxS mutant strains. As an extension of our previous work, where the expression of the mexAB-oprM operon is directly activated by CpxR in P. aeruginosa, in this study, we showed that the expression of the mexA promoter was increased in the above cpxS mutant strains in a cpxR-dependent manner, and mexA is prerequisite for the reduced antibiotic susceptibility. Therefore, we propose that the putative sensor kinase CpxS, together with CpxR, comprises a two-component regulatory system regulating the expression of the mexAB-oprM operon in P. aeruginosa. Our work indicates that cpxS, as a novel member of mutational resistome, plays important roles on the development of multidrug resistance in P. aeruginosa.
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Affiliation(s)
- Zhe-Xian Tian
- State Key Laboratory of Protein and Plant Gene Research,School of Life Sciences, Peking University, Beijing, China
| | - Yi-Ping Wang
- State Key Laboratory of Protein and Plant Gene Research,School of Life Sciences, Peking University, Beijing, China
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6
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Ropponen HK, Diamanti E, Johannsen S, Illarionov B, Hamid R, Jaki M, Sass P, Fischer M, Haupenthal J, Hirsch AKH. Exploring the Translational Gap of a Novel Class of Escherichia coli IspE Inhibitors. ChemMedChem 2023; 18:e202300346. [PMID: 37718320 DOI: 10.1002/cmdc.202300346] [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: 07/05/2023] [Revised: 09/15/2023] [Accepted: 09/15/2023] [Indexed: 09/19/2023]
Abstract
Discovery of novel antibiotics needs multidisciplinary approaches to gain target enzyme and bacterial activities while aiming for selectivity over mammalian cells. Here, we report a multiparameter optimisation of a fragment-like hit that was identified through a structure-based virtual-screening campaign on Escherichia coli IspE crystal structure. Subsequent medicinal-chemistry design resulted in a novel class of E. coli IspE inhibitors, exhibiting activity also against the more pathogenic bacteria Pseudomonas aeruginosa and Acinetobacter baumannii. While cytotoxicity remains a challenge for the series, it provides new insights on the molecular properties for balancing enzymatic target and bacterial activities simultaneously as well as new starting points for the development of IspE inhibitors with a predicted new mode of action.
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Affiliation(s)
- Henni-Karoliina Ropponen
- Drug Discovery and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus Building E8.1, 66123, Saarbrücken, Germany
- Saarland University, Department of Pharmacy, Campus Building E8.1, 66123, Saarbrücken, Germany
- Current address: AMR Action Fund GP GmbH, Messeplatz 10, 4058, Basel, Switzerland
| | - Eleonora Diamanti
- Drug Discovery and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus Building E8.1, 66123, Saarbrücken, Germany
| | - Sandra Johannsen
- Drug Discovery and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus Building E8.1, 66123, Saarbrücken, Germany
- Saarland University, Department of Pharmacy, Campus Building E8.1, 66123, Saarbrücken, Germany
| | - Boris Illarionov
- Hamburg School of Food Science, Institute of Food Chemistry, Grindelallee 117, 20146, Hamburg, Germany
| | - Rawia Hamid
- Drug Discovery and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus Building E8.1, 66123, Saarbrücken, Germany
- Saarland University, Department of Pharmacy, Campus Building E8.1, 66123, Saarbrücken, Germany
| | - Miriam Jaki
- Drug Discovery and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus Building E8.1, 66123, Saarbrücken, Germany
- Saarland University, Department of Pharmacy, Campus Building E8.1, 66123, Saarbrücken, Germany
- Current address: University of Freiburg, Institute of Pharmaceutical Sciences, Department of Pharmaceutics, Sonnenstraße 5, 79104, Freiburg, Germany
| | - Peter Sass
- Interfaculty Institute of Microbiology and Infection Medicine, Universität Tubingen
| | - Markus Fischer
- Hamburg School of Food Science, Institute of Food Chemistry, Grindelallee 117, 20146, Hamburg, Germany
| | - Jörg Haupenthal
- Drug Discovery and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus Building E8.1, 66123, Saarbrücken, Germany
| | - Anna K H Hirsch
- Drug Discovery and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus Building E8.1, 66123, Saarbrücken, Germany
- Saarland University, Department of Pharmacy, Campus Building E8.1, 66123, Saarbrücken, Germany
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7
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Hogan AM, Rahman ASMZ, Motnenko A, Natarajan A, Maydaniuk DT, León B, Batun Z, Palacios A, Bosch A, Cardona ST. Profiling cell envelope-antibiotic interactions reveals vulnerabilities to β-lactams in a multidrug-resistant bacterium. Nat Commun 2023; 14:4815. [PMID: 37558695 PMCID: PMC10412643 DOI: 10.1038/s41467-023-40494-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 07/28/2023] [Indexed: 08/11/2023] Open
Abstract
The cell envelope of Gram-negative bacteria belonging to the Burkholderia cepacia complex (Bcc) presents unique restrictions to antibiotic penetration. As a consequence, Bcc species are notorious for causing recalcitrant multidrug-resistant infections in immunocompromised individuals. Here, we present the results of a genome-wide screen for cell envelope-associated resistance and susceptibility determinants in a Burkholderia cenocepacia clinical isolate. For this purpose, we construct a high-density, randomly-barcoded transposon mutant library and expose it to 19 cell envelope-targeting antibiotics. By quantifying relative mutant fitness with BarSeq, followed by validation with CRISPR-interference, we profile over a hundred functional associations and identify mediators of antibiotic susceptibility in the Bcc cell envelope. We reveal connections between β-lactam susceptibility, peptidoglycan synthesis, and blockages in undecaprenyl phosphate metabolism. The synergy of the β-lactam/β-lactamase inhibitor combination ceftazidime/avibactam is primarily mediated by inhibition of the PenB carbapenemase. In comparison with ceftazidime, avibactam more strongly potentiates the activity of aztreonam and meropenem in a panel of Bcc clinical isolates. Finally, we characterize in Bcc the iron and receptor-dependent activity of the siderophore-cephalosporin antibiotic, cefiderocol. Our work has implications for antibiotic target prioritization, and for using additional combinations of β-lactam/β-lactamase inhibitors that can extend the utility of current antibacterial therapies.
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Affiliation(s)
- Andrew M Hogan
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | | | - Anna Motnenko
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Aakash Natarajan
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Dustin T Maydaniuk
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Beltina León
- CINDEFI, CONICET-CCT La Plata, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Zayra Batun
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Armando Palacios
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Alejandra Bosch
- CINDEFI, CONICET-CCT La Plata, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Silvia T Cardona
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada.
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, Manitoba, Canada.
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8
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Avakh A, Grant GD, Cheesman MJ, Kalkundri T, Hall S. The Art of War with Pseudomonas aeruginosa: Targeting Mex Efflux Pumps Directly to Strategically Enhance Antipseudomonal Drug Efficacy. Antibiotics (Basel) 2023; 12:1304. [PMID: 37627724 PMCID: PMC10451789 DOI: 10.3390/antibiotics12081304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/26/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
Pseudomonas aeruginosa (P. aeruginosa) poses a grave clinical challenge due to its multidrug resistance (MDR) phenotype, leading to severe and life-threatening infections. This bacterium exhibits both intrinsic resistance to various antipseudomonal agents and acquired resistance against nearly all available antibiotics, contributing to its MDR phenotype. Multiple mechanisms, including enzyme production, loss of outer membrane proteins, target mutations, and multidrug efflux systems, contribute to its antimicrobial resistance. The clinical importance of addressing MDR in P. aeruginosa is paramount, and one pivotal determinant is the resistance-nodulation-division (RND) family of drug/proton antiporters, notably the Mex efflux pumps. These pumps function as crucial defenders, reinforcing the emergence of extensively drug-resistant (XDR) and pandrug-resistant (PDR) strains, which underscores the urgency of the situation. Overcoming this challenge necessitates the exploration and development of potent efflux pump inhibitors (EPIs) to restore the efficacy of existing antipseudomonal drugs. By effectively countering or bypassing efflux activities, EPIs hold tremendous potential for restoring the antibacterial activity against P. aeruginosa and other Gram-negative pathogens. This review focuses on concurrent MDR, highlighting the clinical significance of efflux pumps, particularly the Mex efflux pumps, in driving MDR. It explores promising EPIs and delves into the structural characteristics of the MexB subunit and its substrate binding sites.
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Affiliation(s)
| | | | | | | | - Susan Hall
- School of Pharmacy and Medical Sciences, Griffith University, Gold Coast, QLD 4222, Australia; (A.A.); (G.D.G.); (M.J.C.); (T.K.)
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9
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Aljohani AM, El-Chami C, Alhubail M, Ledder RG, O’Neill CA, McBain AJ. Escherichia coli Nissle 1917 inhibits biofilm formation and mitigates virulence in Pseudomonas aeruginosa. Front Microbiol 2023; 14:1108273. [PMID: 36970701 PMCID: PMC10031955 DOI: 10.3389/fmicb.2023.1108273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 01/31/2023] [Indexed: 03/10/2023] Open
Abstract
In the quest for mitigators of bacterial virulence, cell-free supernatants (CFS) from 25 human commensal and associated bacteria were tested for activity against Pseudomonas aeruginosa. Among these, Escherichia coli Nissle 1917 CFS significantly inhibited biofilm formation and dispersed extant pseudomonas biofilms without inhibiting planktonic bacterial growth. eDNA was reduced in biofilms following exposure to E. coli Nissle CFS, as visualized by confocal microscopy. E. coli Nissle CFS also showed a significant protective effect in a Galleria mellonella-based larval virulence assay when administrated 24 h before challenge with the P. aeruginosa. No inhibitory effects against P. aeruginosa were observed for other tested E. coli strains. According to proteomic analysis, E. coli Nissle CFS downregulated the expression of several P. aeruginosa proteins involved in motility (Flagellar secretion chaperone FliSB, B-type flagellin fliC, Type IV pilus assembly ATPase PilB), and quorum sensing (acyl-homoserine lactone synthase lasI and HTH-type quorum-sensing regulator rhlR), which are associated with biofilm formation. Physicochemical characterization of the putative antibiofilm compound(s) indicates the involvement of heat-labile proteinaceous factors of greater than 30 kDa molecular size.
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Affiliation(s)
- Ahmad M. Aljohani
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Ministry of Education, Riyadh, Saudi Arabia
| | - Cecile El-Chami
- Division of Musculoskeletal and Dermatological Science, Faculty of Biology, Medicine and Health, School of Biological Science, The University of Manchester, Manchester, United Kingdom
| | - Muna Alhubail
- Division of Musculoskeletal and Dermatological Science, Faculty of Biology, Medicine and Health, School of Biological Science, The University of Manchester, Manchester, United Kingdom
| | - Ruth G. Ledder
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Catherine A. O’Neill
- Division of Musculoskeletal and Dermatological Science, Faculty of Biology, Medicine and Health, School of Biological Science, The University of Manchester, Manchester, United Kingdom
| | - Andrew J. McBain
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- *Correspondence: Andrew J. McBain,
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10
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Off-Target Integron Activity Leads to Rapid Plasmid Compensatory Evolution in Response to Antibiotic Selection Pressure. mBio 2023; 14:e0253722. [PMID: 36840554 PMCID: PMC10127599 DOI: 10.1128/mbio.02537-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
Integrons are mobile genetic elements that have played an important role in the dissemination of antibiotic resistance. Under stress, the integron can generate combinatorial variation in resistance cassette expression by cassette reshuffling, accelerating the evolution of resistance. However, the flexibility of the integron integrase site recognition motif hints at potential off-target effects of the integrase on the rest of the genome that may have important evolutionary consequences. Here, we test this hypothesis by selecting for increased-piperacillin-resistance populations of Pseudomonas aeruginosa with a mobile integron containing a difficult-to-mobilize β-lactamase cassette to minimize the potential for adaptive cassette reshuffling. We found that integron activity can decrease the overall survival rate but also improve the fitness of the surviving populations. Off-target inversions mediated by the integron accelerated plasmid adaptation by disrupting costly conjugative genes otherwise mutated in control populations lacking a functional integrase. Plasmids containing integron-mediated inversions were associated with lower plasmid costs and higher stability than plasmids carrying mutations albeit at the cost of a reduced conjugative ability. These findings highlight the potential for integrons to create structural variation that can drive bacterial evolution, and they provide an interesting example showing how antibiotic pressure can drive the loss of conjugative genes. IMPORTANCE Tackling the public health challenge created by antibiotic resistance requires understanding the mechanisms driving its evolution. Mobile integrons are widespread genetic platforms heavily involved in the spread of antibiotic resistance. Through the action of the integrase enzyme, integrons allow bacteria to capture, excise, and shuffle antibiotic resistance gene cassettes. This integrase enzyme is characterized by its ability to recognize a wide range of recombination sites, which allows it to easily capture diverse resistance cassettes but which may also lead to off-target reactions with the rest of the genome. Using experimental evolution, we tested the off-target impact of integron activity. We found that integrons increased the fitness of the surviving bacteria through extensive genomic rearrangements of the plasmids carrying the integrons, reducing their ability to spread horizontally. These results show that integrons not only accelerate resistance evolution but also can generate extensive structural variation, driving bacterial evolution beyond antibiotic resistance.
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11
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Update on the Discovery of Efflux Pump Inhibitors against Critical Priority Gram-Negative Bacteria. Antibiotics (Basel) 2023; 12:antibiotics12010180. [PMID: 36671381 PMCID: PMC9854755 DOI: 10.3390/antibiotics12010180] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Antimicrobial resistance (AMR) has become a major problem in public health leading to an estimated 4.95 million deaths in 2019. The selective pressure caused by the massive and repeated use of antibiotics has led to bacterial strains that are partially or even entirely resistant to known antibiotics. AMR is caused by several mechanisms, among which the (over)expression of multidrug efflux pumps plays a central role. Multidrug efflux pumps are transmembrane transporters, naturally expressed by Gram-negative bacteria, able to extrude and confer resistance to several classes of antibiotics. Targeting them would be an effective way to revive various options for treatment. Many efflux pump inhibitors (EPIs) have been described in the literature; however, none of them have entered clinical trials to date. This review presents eight families of EPIs active against Escherichia coli or Pseudomonas aeruginosa. Structure-activity relationships, chemical synthesis, in vitro and in vivo activities, and pharmacological properties are reported. Their binding sites and their mechanisms of action are also analyzed comparatively.
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12
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Ramsay KA, Rehman A, Wardell ST, Martin LW, Bell SC, Patrick WM, Winstanley C, Lamont IL. Ceftazidime resistance in Pseudomonas aeruginosa is multigenic and complex. PLoS One 2023; 18:e0285856. [PMID: 37192202 DOI: 10.1371/journal.pone.0285856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 05/02/2023] [Indexed: 05/18/2023] Open
Abstract
Pseudomonas aeruginosa causes a wide range of severe infections. Ceftazidime, a cephalosporin, is a key antibiotic for treating infections but a significant proportion of isolates are ceftazidime-resistant. The aim of this research was to identify mutations that contribute to resistance, and to quantify the impacts of individual mutations and mutation combinations. Thirty-five mutants with reduced susceptibility to ceftazidime were evolved from two antibiotic-sensitive P. aeruginosa reference strains PAO1 and PA14. Mutations were identified by whole genome sequencing. The evolved mutants tolerated ceftazidime at concentrations between 4 and 1000 times that of the parental bacteria, with most mutants being ceftazidime resistant (minimum inhibitory concentration [MIC] ≥ 32 mg/L). Many mutants were also resistant to meropenem, a carbapenem antibiotic. Twenty-eight genes were mutated in multiple mutants, with dacB and mpl being the most frequently mutated. Mutations in six key genes were engineered into the genome of strain PAO1 individually and in combinations. A dacB mutation by itself increased the ceftazidime MIC by 16-fold although the mutant bacteria remained ceftazidime sensitive (MIC < 32 mg/L). Mutations in ampC, mexR, nalC or nalD increased the MIC by 2- to 4-fold. The MIC of a dacB mutant was increased when combined with a mutation in ampC, rendering the bacteria resistant, whereas other mutation combinations did not increase the MIC above those of single mutants. To determine the clinical relevance of mutations identified through experimental evolution, 173 ceftazidime-resistant and 166 sensitive clinical isolates were analysed for the presence of sequence variants that likely alter function of resistance-associated genes. dacB and ampC sequence variants occur most frequently in both resistant and sensitive clinical isolates. Our findings quantify the individual and combinatorial effects of mutations in different genes on ceftazidime susceptibility and demonstrate that the genetic basis of ceftazidime resistance is complex and multifactorial.
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Affiliation(s)
- Kay A Ramsay
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Attika Rehman
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Samuel T Wardell
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Lois W Martin
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Scott C Bell
- Department of Thoracic Medicine, The Prince Charles Hospital, Chermside, Queensland, Australia
- Children's Health Research Centre, Faculty of Medicine, The University of Queensland, South Brisbane, Queensland, Australia
| | - Wayne M Patrick
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Craig Winstanley
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Iain L Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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13
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Dulanto Chiang A, Patil PP, Beka L, Youn JH, Launay A, Bonomo RA, Khil PP, Dekker JP. Hypermutator strains of Pseudomonas aeruginosa reveal novel pathways of resistance to combinations of cephalosporin antibiotics and beta-lactamase inhibitors. PLoS Biol 2022; 20:e3001878. [PMID: 36399436 PMCID: PMC9718400 DOI: 10.1371/journal.pbio.3001878] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 12/02/2022] [Accepted: 10/13/2022] [Indexed: 11/19/2022] Open
Abstract
Hypermutation due to DNA mismatch repair (MMR) deficiencies can accelerate the development of antibiotic resistance in Pseudomonas aeruginosa. Whether hypermutators generate resistance through predominantly similar molecular mechanisms to wild-type (WT) strains is not fully understood. Here, we show that MMR-deficient P. aeruginosa can evolve resistance to important broad-spectrum cephalosporin/beta-lactamase inhibitor combination antibiotics through novel mechanisms not commonly observed in WT lineages. Using whole-genome sequencing (WGS) and transcriptional profiling of isolates that underwent in vitro adaptation to ceftazidime/avibactam (CZA), we characterized the detailed sequence of mutational and transcriptional changes underlying the development of resistance. Surprisingly, MMR-deficient lineages rapidly developed high-level resistance (>256 μg/mL) largely without corresponding fixed mutations or transcriptional changes in well-established resistance genes. Further investigation revealed that these isolates had paradoxically generated an early inactivating mutation in the mexB gene of the MexAB-OprM efflux pump, a primary mediator of CZA resistance in P. aeruginosa, potentially driving an evolutionary search for alternative resistance mechanisms. In addition to alterations in a number of genes not known to be associated with resistance, 2 mutations were observed in the operon encoding the RND efflux pump MexVW. These mutations resulted in a 4- to 6-fold increase in resistance to ceftazidime, CZA, cefepime, and ceftolozane-tazobactam when engineered into a WT strain, demonstrating a potentially important and previously unappreciated mechanism of resistance to these antibiotics in P. aeruginosa. Our results suggest that MMR-deficient isolates may rapidly evolve novel resistance mechanisms, sometimes with complex dynamics that reflect gene inactivation that occurs with hypermutation. The apparent ease with which hypermutators may switch to alternative resistance mechanisms for which antibiotics have not been developed may carry important clinical implications.
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Affiliation(s)
- Augusto Dulanto Chiang
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, LCIM, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Prashant P. Patil
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, LCIM, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Lidia Beka
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, LCIM, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Jung-Ho Youn
- Dept. Laboratory Medicine, NIH Clinical Center, NIH, Bethesda, Maryland, United States of America
| | - Adrien Launay
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, LCIM, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Robert A. Bonomo
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, United States of America
- Departments of Pharmacology, Molecular Biology and Microbiology, Biochemistry, and Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES) Cleveland, Ohio, United States of America
| | - Pavel P. Khil
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, LCIM, NIAID, NIH, Bethesda, Maryland, United States of America
- Dept. Laboratory Medicine, NIH Clinical Center, NIH, Bethesda, Maryland, United States of America
| | - John P. Dekker
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, LCIM, NIAID, NIH, Bethesda, Maryland, United States of America
- Dept. Laboratory Medicine, NIH Clinical Center, NIH, Bethesda, Maryland, United States of America
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14
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Singla A, Simbassa SB, Chirra B, Gairola A, Southerland MR, Shah KN, Rose RE, Chen Q, Basharat A, Baeza J, Raina R, Chapman MJ, Hassan AM, Ivanov I, Sen A, Wu HJ, Cannon CL. Hetero-Multivalent Targeted Liposomal Drug Delivery to Treat Pseudomonas aeruginosa Infections. ACS APPLIED MATERIALS & INTERFACES 2022; 14:40724-40737. [PMID: 36018830 PMCID: PMC9480101 DOI: 10.1021/acsami.2c12943] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
Pseudomonas aeruginosa is the leading nosocomial and community-acquired pathogen causing a plethora of acute and chronic infections. The Centers for Disease Control and Prevention has designated multidrug-resistant isolates of P. aeruginosa as a serious threat. A novel delivery vehicle capable of specifically targeting P. aeruginosa, and encapsulating antimicrobials, may address the challenges associated with these infections. We have developed hetero-multivalent targeted liposomes functionalized with host cell glycans to increase the delivery of antibiotics to the site of infection. Previously, we have demonstrated that compared with monovalent liposomes, these hetero-multivalent liposomes bind with higher affinity to P. aeruginosa. Here, compared with nontargeted liposomes, we have shown that greater numbers of targeted liposomes are found in the circulation, as well as at the site of P. aeruginosa (PAO1) infection in the thighs of CD-1 mice. No significant difference was found in the uptake of targeted, nontargeted, and PEGylated liposomes by J774.A1 macrophages. Ciprofloxacin-loaded liposomes were formulated and characterized for size, encapsulation, loading, and drug release. In vitro antimicrobial efficacy was assessed using CLSI broth microdilution assays and time-kill kinetics. Lastly, PAO1-inoculated mice treated with ciprofloxacin-loaded, hetero-multivalent targeted liposomes survived longer than mice treated with ciprofloxacin-loaded, monovalent targeted, or nontargeted liposomes and free ciprofloxacin. Thus, liposomes functionalized with host cell glycans target P. aeruginosa resulting in increased retention of the liposomes in the circulation, accumulation at the site of infection, and increased survival time in a mouse surgical site infection model. Consequently, this formulation strategy may improve outcomes in patients infected with P. aeruginosa.
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Affiliation(s)
- Akshi Singla
- Department
of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Sabona B. Simbassa
- Department
of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan Texas 77807, United States
| | - Bhagath Chirra
- Department
of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan Texas 77807, United States
| | - Anirudh Gairola
- Department
of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Marie R. Southerland
- Department
of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan Texas 77807, United States
| | - Kush N. Shah
- Department
of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan Texas 77807, United States
| | - Robert E. Rose
- Comparative
Medicine Program, Texas A&M University, College Station, Texas 77843, United States
| | - Qingquan Chen
- Department
of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan Texas 77807, United States
| | - Ahmed Basharat
- Department
of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan Texas 77807, United States
| | - Jaime Baeza
- Department
of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan Texas 77807, United States
| | - Rohit Raina
- Department
of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan Texas 77807, United States
| | - Morgan J. Chapman
- Department
of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan Texas 77807, United States
| | - Adel M. Hassan
- Department
of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan Texas 77807, United States
| | - Ivan Ivanov
- Department
of Veterinary Physiology and Pharmacology, Texas A&M University, College
Station, Texas 77843, United States
| | - Anindito Sen
- Microscopy
and Imaging Center, Texas A&M University, College Station, Texas 77843, United States
| | - Hung-Jen Wu
- Department
of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Carolyn L. Cannon
- Department
of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, Bryan Texas 77807, United States
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15
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Evaluation of a Conformationally Constrained Indole Carboxamide as a Potential Efflux Pump Inhibitor in Pseudomonas aeruginosa. Antibiotics (Basel) 2022; 11:antibiotics11060716. [PMID: 35740123 PMCID: PMC9220351 DOI: 10.3390/antibiotics11060716] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/16/2022] [Accepted: 05/23/2022] [Indexed: 11/17/2022] Open
Abstract
Efflux pumps in Gram-negative bacteria such as Pseudomonas aeruginosa provide intrinsic antimicrobial resistance by facilitating the extrusion of a wide range of antimicrobials. Approaches for combating efflux-mediated multidrug resistance involve, in part, developing indirect antimicrobial agents capable of inhibiting efflux, thus rescuing the activity of antimicrobials previously rendered inactive by efflux. Herein, TXA09155 is presented as a novel efflux pump inhibitor (EPI) formed by conformationally constraining our previously reported EPI TXA01182. TXA09155 demonstrates strong potentiation in combination with multiple antibiotics with efflux liabilities against wild-type and multidrug-resistant (MDR) P. aeruginosa. At 6.25 µg/mL, TXA09155, showed ≥8-fold potentiation of levofloxacin, moxifloxacin, doxycycline, minocycline, cefpirome, chloramphenicol, and cotrimoxazole. Several biophysical and genetic studies rule out membrane disruption and support efflux inhibition as the mechanism of action (MOA) of TXA09155. TXA09155 was determined to lower the frequency of resistance (FoR) to levofloxacin and enhance the killing kinetics of moxifloxacin. Most importantly, TXA09155 outperformed the levofloxacin-potentiation activity of EPIs TXA01182 and MC-04,124 against a CDC/FDA panel of MDR clinical isolates of P. aeruginosa. TXA09155 possesses favorable physiochemical and ADME properties that warrant its optimization and further development.
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16
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Express Yourself: Quantitative Real-Time PCR Assays for Rapid Chromosomal Antimicrobial Resistance Detection in Pseudomonas aeruginosa. Antimicrob Agents Chemother 2022; 66:e0020422. [PMID: 35467369 DOI: 10.1128/aac.00204-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The rise of antimicrobial-resistant (AMR) bacteria is a global health emergency. One critical facet of tackling this epidemic is more rapid AMR diagnosis in serious multidrug-resistant pathogens like Pseudomonas aeruginosa. Here, we designed and then validated two multiplex quantitative real-time PCR (qPCR) assays to simultaneously detect differential expression of the resistance-nodulation-division efflux pumps MexAB-OprM, MexCD-OprJ, MexEF-OprN, and MexXY-OprM, the AmpC β-lactamase, and the porin OprD, which are commonly associated with chromosomally encoded AMR. Next, qPCRs were tested on 15 sputa from 11 participants with P. aeruginosa respiratory infections to determine AMR profiles in vivo. We confirmed multiplex qPCR testing feasibility directly on sputa, representing a key advancement in in vivo AMR diagnosis. Notably, comparison of sputa with their derived isolates grown in Luria-Bertani broth (±2.5% NaCl) or a 5-antibiotic cocktail showed marked expression differences, illustrating the difficulty in replicating in vivo expression profiles in vitro. Cystic fibrosis sputa showed significantly reduced mexE and mexY expression compared with chronic obstructive pulmonary disease sputa, despite harboring fluoroquinolone- and aminoglycoside-resistant strains, indicating that these loci do not contribute to AMR in vivo. oprD was also significantly downregulated in cystic fibrosis sputa, even in the absence of contemporaneous carbapenem use, suggesting a common adaptive trait in chronic infections that may affect carbapenem efficacy. Sputum ampC expression was highest in participants receiving carbapenems (6.7 to 15×), some of whom were simultaneously receiving cephalosporins, the latter of which would be rendered ineffective by the upregulated ampC. Our qPCR assays provide valuable insights into the P. aeruginosa resistome, and their use on clinical specimens will permit timely treatment alterations that will improve patient outcomes and antimicrobial stewardship measures.
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17
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Zhang J, Li G, Zhang G, Kang W, Duan S, Wang T, Li J, Huangfu Z, Yang Q, Xu Y, Jia W, Sun H. Performance Evaluation of the Gradient Diffusion Strip Method and Disk Diffusion Method for Ceftazidime-Avibactam Against Enterobacterales and Pseudomonas aeruginosa: A Dual-Center Study. Front Microbiol 2021; 12:710526. [PMID: 34603236 PMCID: PMC8481768 DOI: 10.3389/fmicb.2021.710526] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 08/13/2021] [Indexed: 12/02/2022] Open
Abstract
Objectives: Ceftazidime–avibactam is a novel synthetic beta-lactam + beta-lactamase inhibitor combination. We evaluated the performance of the gradient diffusion strip method and the disk diffusion method for the determination of ceftazidime–avibactam against Enterobacterales and Pseudomonas aeruginosa. Methods: Antimicrobial susceptibility testing of 302 clinical Enterobacterales and Pseudomonas aeruginosa isolates from two centers were conducted by broth microdilution (BMD), gradient diffusion strip method, and disk diffusion method for ceftazidime–avibactam. Using BMD as a gold standard, essential agreement (EA), categorical agreement (CA), major error (ME), and very major error (VME) were determined according to CLSI guidelines. CA and EA rate > 90%, ME rate < 3%, and VME rate < 1.5% were considered as acceptable criteria. Polymerase chain reaction and Sanger sequencing were performed to determine the carbapenem resistance genes of all 302 isolates. Results: A total of 302 strains were enrolled, among which 182 strains were from center 1 and 120 strains were from center 2. A percentage of 18.21% (55/302) of the enrolled isolates were resistant to ceftazidime–avibactam. The CA rates of the gradient diffusion strip method for Enterobacterales and P. aeruginosa were 100% and 98.65% (73/74), respectively, and the EA rates were 97.37% (222/228) and 98.65% (73/74), respectively. The CA rates of the disk diffusion method for Enterobacterales and P. aeruginosa were 100% and 95.95% (71/74), respectively. No VMEs were found by using the gradient diffusion strip method, while the ME rate was 0.40% (1/247). No MEs were found by using the disk diffusion method, but the VME rate was 5.45% (3/55). Therefore, all the parameters of the gradient diffusion strip method were in line with acceptable criteria. For 31 blaKPC, 33 blaNDM, 7 blaIMP, and 2 blaVIM positive isolates, both CA and EA rates were 100%; no MEs or VMEs were detected by either method. For 15 carbapenemase-non-producing resistant isolates, the CA and EA rates of the gradient diffusion strips method were 100%. Whereas the CA rate of the disk diffusion method was 80.00% (12/15), the VME rate was 20.00% (3/15). Conclusion: The gradient diffusion strip method can meet the needs of clinical microbiological laboratories for testing the susceptibility of ceftazidime–avibactam drugs. However, the VME rate > 1.5% (5.45%) by the disk diffusion method. By comparison, the performance of the gradient diffusion strip method was better than that of the disk diffusion method.
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Affiliation(s)
- Jingjia Zhang
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Gang Li
- Medical Experimental Center, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Ge Zhang
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Wei Kang
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Simeng Duan
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Tong Wang
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Jin Li
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Zhiru Huangfu
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Qiwen Yang
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Yingchun Xu
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Wei Jia
- Medical Experimental Center, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Hongli Sun
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
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18
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Outer membrane permeability: Antimicrobials and diverse nutrients bypass porins in Pseudomonas aeruginosa. Proc Natl Acad Sci U S A 2021; 118:2107644118. [PMID: 34326266 PMCID: PMC8346889 DOI: 10.1073/pnas.2107644118] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Novel antibiotics are urgently needed to resolve the current antimicrobial resistance crisis. For critical pathogens, drug entry through the cell envelope is one of the major challenges in the development of effective novel antibiotics. Envelope proteins forming water-filled channels, so-called porins, are commonly thought to be essential for entry of hydrophilic molecules, but we show here for the critical pathogen Pseudomonas aeruginosa that almost all antibiotics and diverse hydrophilic nutrients bypass porins and instead permeate directly through the outer membrane lipid bilayer. However, carboxylate groups hinder bilayer penetration, and Pseudomonas thus needs porins for efficient utilization of carboxylate-containing nutrients such as succinate. The major porin-independent entry route might open opportunities for facilitating drug delivery into bacteria. Gram-negative bacterial pathogens have an outer membrane that restricts entry of molecules into the cell. Water-filled protein channels in the outer membrane, so-called porins, facilitate nutrient uptake and are thought to enable antibiotic entry. Here, we determined the role of porins in a major pathogen, Pseudomonas aeruginosa, by constructing a strain lacking all 40 identifiable porins and 15 strains carrying only a single unique type of porin and characterizing these strains with NMR metabolomics and antimicrobial susceptibility assays. In contrast to common assumptions, all porins were dispensable for Pseudomonas growth in rich medium and consumption of diverse hydrophilic nutrients. However, preferred nutrients with two or more carboxylate groups such as succinate and citrate permeated poorly in the absence of porins. Porins provided efficient translocation pathways for these nutrients with broad and overlapping substrate selectivity while efficiently excluding all tested antibiotics except carbapenems, which partially entered through OprD. Porin-independent permeation of antibiotics through the outer-membrane lipid bilayer was hampered by carboxylate groups, consistent with our nutrient data. Together, these results challenge common assumptions about the role of porins by demonstrating porin-independent permeation of the outer-membrane lipid bilayer as a major pathway for nutrient and drug entry into the bacterial cell.
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Alford MA, Baquir B, An A, Choi KYG, Hancock REW. NtrBC Selectively Regulates Host-Pathogen Interactions, Virulence, and Ciprofloxacin Susceptibility of Pseudomonas aeruginosa. Front Cell Infect Microbiol 2021; 11:694789. [PMID: 34249781 PMCID: PMC8264665 DOI: 10.3389/fcimb.2021.694789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/03/2021] [Indexed: 12/11/2022] Open
Abstract
Pseudomonas aeruginosa is a metabolically versatile opportunistic pathogen capable of infecting distinct niches of the human body, including skin wounds and the lungs of cystic fibrosis patients. Eradication of P. aeruginosa infection is becoming increasingly difficult due to the numerous resistance mechanisms it employs. Adaptive resistance is characterized by a transient state of decreased susceptibility to antibiotic therapy that is distinct from acquired or intrinsic resistance, can be triggered by various environmental stimuli and reverted by removal of the stimulus. Further, adaptive resistance is intrinsically linked to lifestyles such as swarming motility and biofilm formation, both of which are important in infections and lead to multi-drug adaptive resistance. Here, we demonstrated that NtrBC, the master of nitrogen control, had a selective role in host colonization and a substantial role in determining intrinsic resistance to ciprofloxacin. P. aeruginosa mutant strains (ΔntrB, ΔntrC and ΔntrBC) colonized the skin but not the respiratory tract of mice as well as WT and, unlike WT, could be reduced or eradicated from the skin by ciprofloxacin. We hypothesized that nutrient availability contributed to these phenomena and found that susceptibility to ciprofloxacin was impacted by nitrogen source in laboratory media. P. aeruginosa ΔntrB, ΔntrC and ΔntrBC also exhibited distinct host interactions, including modestly increased cytotoxicity toward human bronchial epithelial cells, reduced virulence factor production and 10-fold increased uptake by macrophages. These data might explain why NtrBC mutants were less adept at colonizing the upper respiratory tract of mice. Thus, NtrBC represents a link between nitrogen metabolism, adaptation and virulence of the pathogen P. aeruginosa, and could represent a target for eradication of recalcitrant infections in situ.
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Affiliation(s)
- Morgan A Alford
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Beverlie Baquir
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Andy An
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Ka-Yee G Choi
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
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Gene-Gene Interactions Dictate Ciprofloxacin Resistance in Pseudomonas aeruginosa and Facilitate Prediction of Resistance Phenotype from Genome Sequence Data. Antimicrob Agents Chemother 2021; 65:e0269620. [PMID: 33875431 DOI: 10.1128/aac.02696-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ciprofloxacin is one of the most widely used antibiotics for treating Pseudomonas aeruginosa infections. However, P. aeruginosa acquires mutations that confer ciprofloxacin resistance, making treatment more difficult. Resistance is multifactorial, with mutations in multiple genes influencing the resistance phenotype. However, the contributions of individual mutations and mutation combinations to the amounts of ciprofloxacin that P. aeruginosa can tolerate are not well understood. Engineering P. aeruginosa strain PAO1 to contain mutations in any one of the resistance-associated genes gyrA, nfxB, rnfC, parC, and parE showed that only gyrA mutations increased the MIC for ciprofloxacin. Mutations in parC and parE increased the MIC of a gyrA mutant, making the bacteria ciprofloxacin resistant. Mutations in nfxB and rnfC increased the MIC, conferring resistance, only if both were mutated in a gyrA background. Mutations in all of gyrA, nfxB, rnfC, and parC/E further increased the MIC. These findings reveal an epistatic network of gene-gene interactions in ciprofloxacin resistance. We used this information to predict ciprofloxacin resistance/susceptibility for 274 isolates of P. aeruginosa from their genome sequences. Antibiotic susceptibility profiles were predicted correctly for 84% of the isolates. The majority of isolates for which prediction was unsuccessful were ciprofloxacin resistant, demonstrating the involvement of additional as yet unidentified genes and mutations in resistance. Our data show that gene-gene interactions can play an important role in antibiotic resistance and can be successfully incorporated into models predicting resistance phenotype.
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21
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Gil-Gil T, Ochoa-Sánchez LE, Baquero F, Martínez JL. Antibiotic resistance: Time of synthesis in a post-genomic age. Comput Struct Biotechnol J 2021; 19:3110-3124. [PMID: 34141134 PMCID: PMC8181582 DOI: 10.1016/j.csbj.2021.05.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/13/2021] [Accepted: 05/20/2021] [Indexed: 12/20/2022] Open
Abstract
Antibiotic resistance has been highlighted by international organizations, including World Health Organization, World Bank and United Nations, as one of the most relevant global health problems. Classical approaches to study this problem have focused in infected humans, mainly at hospitals. Nevertheless, antibiotic resistance can expand through different ecosystems and geographical allocations, hence constituting a One-Health, Global-Health problem, requiring specific integrative analytic tools. Antibiotic resistance evolution and transmission are multilayer, hierarchically organized processes with several elements (from genes to the whole microbiome) involved. However, their study has been traditionally gene-centric, each element independently studied. The development of robust-economically affordable whole genome sequencing approaches, as well as other -omic techniques as transcriptomics and proteomics, is changing this panorama. These technologies allow the description of a system, either a cell or a microbiome as a whole, overcoming the problems associated with gene-centric approaches. We are currently at the time of combining the information derived from -omic studies to have a more holistic view of the evolution and spread of antibiotic resistance. This synthesis process requires the accurate integration of -omic information into computational models that serve to analyse the causes and the consequences of acquiring AR, fed by curated databases capable of identifying the elements involved in the acquisition of resistance. In this review, we analyse the capacities and drawbacks of the tools that are currently in use for the global analysis of AR, aiming to identify the more useful targets for effective corrective interventions.
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Affiliation(s)
- Teresa Gil-Gil
- Centro Nacional de Biotecnología, CSIC, Darwin 3, 28049 Madrid, Spain
| | | | - Fernando Baquero
- Department of Microbiology, Hospital Universitario Ramón y Cajal (IRYCIS), Madrid, Spain
- CIBER en Epidemiología y Salud Pública (CIBER-ESP), Madrid, Spain
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22
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Barbosa C, Mahrt N, Bunk J, Graßer M, Rosenstiel P, Jansen G, Schulenburg H. The Genomic Basis of Rapid Adaptation to Antibiotic Combination Therapy in Pseudomonas aeruginosa. Mol Biol Evol 2021; 38:449-464. [PMID: 32931584 PMCID: PMC7826179 DOI: 10.1093/molbev/msaa233] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Combination therapy is a common antibiotic treatment strategy that aims at minimizing the risk of resistance evolution in several infectious diseases. Nonetheless, evidence supporting its efficacy against the nosocomial opportunistic pathogen Pseudomonas aeruginosa remains elusive. Identification of the possible evolutionary paths to resistance in multidrug environments can help to explain treatment outcome. For this purpose, we here performed whole-genome sequencing of 127 previously evolved populations of P. aeruginosa adapted to sublethal doses of distinct antibiotic combinations and corresponding single-drug treatments, and experimentally characterized several of the identified variants. We found that alterations in the regulation of efflux pumps are the most favored mechanism of resistance, regardless of the environment. Unexpectedly, we repeatedly identified intergenic variants in the adapted populations, often with no additional mutations and usually associated with genes involved in efflux pump expression, possibly indicating a regulatory function of the intergenic regions. The experimental analysis of these variants demonstrated that the intergenic changes caused similar increases in resistance against single and multidrug treatments as those seen for efflux regulatory gene mutants. Surprisingly, we could find no substantial fitness costs for a majority of these variants, most likely enhancing their competitiveness toward sensitive cells, even in antibiotic-free environments. We conclude that the regulation of efflux is a central target of antibiotic-mediated selection in P. aeruginosa and that, importantly, changes in intergenic regions may represent a usually neglected alternative process underlying bacterial resistance evolution, which clearly deserves further attention in the future.
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Affiliation(s)
- Camilo Barbosa
- Department of Evolutionary Ecology and Genetics, University of Kiel, Kiel, Germany
| | - Niels Mahrt
- Department of Evolutionary Ecology and Genetics, University of Kiel, Kiel, Germany
| | - Julia Bunk
- Department of Evolutionary Ecology and Genetics, University of Kiel, Kiel, Germany
| | - Matthias Graßer
- Department of Evolutionary Ecology and Genetics, University of Kiel, Kiel, Germany
| | | | - Gunther Jansen
- Department of Evolutionary Ecology and Genetics, University of Kiel, Kiel, Germany
- Personalized Healthcare, Data Science Analytics, Roche, Basel, Switzerland
| | - Hinrich Schulenburg
- Department of Evolutionary Ecology and Genetics, University of Kiel, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Ploen, Germany
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Targeting bioenergetics is key to counteracting the drug-tolerant state of biofilm-grown bacteria. PLoS Pathog 2020; 16:e1009126. [PMID: 33351859 PMCID: PMC7787680 DOI: 10.1371/journal.ppat.1009126] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 01/06/2021] [Accepted: 11/05/2020] [Indexed: 12/30/2022] Open
Abstract
Embedded in an extracellular matrix, biofilm-residing bacteria are protected from diverse physicochemical insults. In accordance, in the human host the general recalcitrance of biofilm-grown bacteria hinders successful eradication of chronic, biofilm-associated infections. In this study, we demonstrate that upon addition of promethazine, an FDA approved drug, antibiotic tolerance of in vitro biofilm-grown bacteria can be abolished. We show that following the addition of promethazine, diverse antibiotics are capable of efficiently killing biofilm-residing cells at minimal inhibitory concentrations. Synergistic effects could also be observed in a murine in vivo model system. PMZ was shown to increase membrane potential and interfere with bacterial respiration. Of note, antibiotic killing activity was elevated when PMZ was added to cells grown under environmental conditions that induce low intracellular proton levels. Our results imply that biofilm-grown bacteria avoid antibiotic killing and become tolerant by counteracting intracellular alkalization through the adaptation of metabolic and transport functions. Abrogation of antibiotic tolerance by interfering with the cell’s bioenergetics promises to pave the way for successful eradication of biofilm-associated infections. Repurposing promethazine as a biofilm-sensitizing drug has the potential to accelerate the introduction of new treatments for recalcitrant, biofilm-associated infections into the clinic. At sub-minimal inhibitory concentrations, phenothiazines have been shown to inhibit virulence as well as the formation of biofilms in a wide range of different bacterial pathogens. In this study, we analyzed the anti-bacterial effect of the FDA-approved drug, promethazine, on biofilm-grown Pseudomonas aeruginosa. We demonstrate that PMZ interferes with bacterial bioenergetics and sensitizes biofilm-grown P. aeruginosa cells to bactericidal activity of several different classes of antibiotics by several orders of magnitude. This effect was most pronounced when cells were grown under environmental conditions that induce low intracellular proton levels. Thus, it seems that a reduced proton efflux in cells that exhibit decreased respiratory activity due to their biofilm mode of growth might explain their general antimicrobial tolerance. The use of PMZ as an antibiotic sensitizer holds promise that targeting tolerance mechanisms of biofilm-grown bacteria could become a practicable way to change the way physicians treat biofilm-associated infections.
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Lippa AM, Gebhardt MJ, Dove SL. H-NS-like proteins in Pseudomonas aeruginosa coordinately silence intragenic transcription. Mol Microbiol 2020; 115:1138-1151. [PMID: 33245158 DOI: 10.1111/mmi.14656] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 01/22/2023]
Abstract
The H-NS-like proteins MvaT and MvaU act coordinately as global repressors in Pseudomonas aeruginosa by binding to AT-rich regions of the chromosome. Although cells can tolerate loss of either protein, identifying their combined regulatory effects has been challenging because the loss of both proteins is lethal due to induction of prophage Pf4 and subsequent superinfection of the cell. In other bacteria, H-NS promotes the cellular fitness by inhibiting intragenic transcription from AT-rich target regions, preventing them from sequestering RNA polymerase; however, it is not known whether MvaT and MvaU function similarly. Here, we utilize a parental strain that cannot be infected by Pf4 phage to define the collective MvaT and MvaU regulon and demonstrate that the combined loss of both MvaT and MvaU leads to increased intragenic transcription from loci directly controlled by these proteins. We further show that the loss of MvaT and MvaU leads to a striking redistribution of RNA polymerase containing σ70 to genomic regions vacated by these proteins. Our findings suggest that the ability of H-NS-like proteins to repress intragenic transcription is a universal function of these proteins and point to a second mechanism by which MvaT and MvaU may contribute to the growth of P. aeruginosa.
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Affiliation(s)
- Andrew M Lippa
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Michael J Gebhardt
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Simon L Dove
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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25
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Identification of novel targets of azithromycin activity against Pseudomonas aeruginosa grown in physiologically relevant media. Proc Natl Acad Sci U S A 2020; 117:33519-33529. [PMID: 33318204 DOI: 10.1073/pnas.2007626117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pseudomonas aeruginosa causes severe multidrug-resistant infections that often lead to bacteremia and sepsis. Physiologically relevant conditions can increase the susceptibility of pathogens to antibiotics, such as azithromycin (AZM). When compared to minimal-inhibitory concentrations (MICs) in laboratory media, AZM had a 16-fold lower MIC in tissue culture medium with 5% Mueller Hinton broth (MHB) and a 64-fold lower MIC in this tissue culture medium with 20% human serum. AZM also demonstrated increased synergy in combination with synthetic host-defense peptides DJK-5 and IDR-1018 under host-like conditions and in a murine abscess model. To mechanistically study the altered effects of AZM under physiologically relevant conditions, global transcriptional analysis was performed on P. aeruginosa with and without effective concentrations of AZM. This revealed that the arn operon, mediating arabinosaminylation of lipopolysaccharides and related regulatory systems, was down-regulated in host-like media when compared to MHB. Inactivation of genes within the arn operon led to increased susceptibility of P. aeruginosa to AZM and great increases in synergy between AZM and other antimicrobial agents, indicating that dysregulation of the arn operon might explain increased AZM uptake and synergy in host-like media. Furthermore, genes involved in central and energy metabolism and ribosome biogenesis were dysregulated more in physiologically relevant conditions treated with AZM, likely due to general changes in cell physiology as a result of the increased effectiveness of AZM in these conditions. These data suggest that, in addition to the arn operon, there are multiple factors in host-like environments that are responsible for observed changes in susceptibility.
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Fodor A, Abate BA, Deák P, Fodor L, Gyenge E, Klein MG, Koncz Z, Muvevi J, Ötvös L, Székely G, Vozik D, Makrai L. Multidrug Resistance (MDR) and Collateral Sensitivity in Bacteria, with Special Attention to Genetic and Evolutionary Aspects and to the Perspectives of Antimicrobial Peptides-A Review. Pathogens 2020; 9:pathogens9070522. [PMID: 32610480 PMCID: PMC7399985 DOI: 10.3390/pathogens9070522] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 12/18/2022] Open
Abstract
Antibiotic poly-resistance (multidrug-, extreme-, and pan-drug resistance) is controlled by adaptive evolution. Darwinian and Lamarckian interpretations of resistance evolution are discussed. Arguments for, and against, pessimistic forecasts on a fatal “post-antibiotic era” are evaluated. In commensal niches, the appearance of a new antibiotic resistance often reduces fitness, but compensatory mutations may counteract this tendency. The appearance of new antibiotic resistance is frequently accompanied by a collateral sensitivity to other resistances. Organisms with an expanding open pan-genome, such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae, can withstand an increased number of resistances by exploiting their evolutionary plasticity and disseminating clonally or poly-clonally. Multidrug-resistant pathogen clones can become predominant under antibiotic stress conditions but, under the influence of negative frequency-dependent selection, are prevented from rising to dominance in a population in a commensal niche. Antimicrobial peptides have a great potential to combat multidrug resistance, since antibiotic-resistant bacteria have shown a high frequency of collateral sensitivity to antimicrobial peptides. In addition, the mobility patterns of antibiotic resistance, and antimicrobial peptide resistance, genes are completely different. The integron trade in commensal niches is fortunately limited by the species-specificity of resistance genes. Hence, we theorize that the suggested post-antibiotic era has not yet come, and indeed might never come.
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Affiliation(s)
- András Fodor
- Department of Genetics, University of Szeged, H-6726 Szeged, Hungary;
- Correspondence: or (A.F.); (L.M.); Tel.: +36-(30)-490-9294 (A.F.); +36-(30)-271-2513 (L.M.)
| | - Birhan Addisie Abate
- Ethiopian Biotechnology Institute, Agricultural Biotechnology Directorate, Addis Ababa 5954, Ethiopia;
| | - Péter Deák
- Department of Genetics, University of Szeged, H-6726 Szeged, Hungary;
- Institute of Biochemistry, Biological Research Centre, H-6726 Szeged, Hungary
| | - László Fodor
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, P.O. Box 22, H-1581 Budapest, Hungary;
| | - Ervin Gyenge
- Hungarian Department of Biology and Ecology, Faculty of Biology and Geology, Babeș-Bolyai University, 5-7 Clinicilor St., 400006 Cluj-Napoca, Romania; (E.G.); (G.S.)
- Institute for Research-Development-Innovation in Applied Natural Sciences, Babeș-Bolyai University, 30 Fântânele St., 400294 Cluj-Napoca, Romania
| | - Michael G. Klein
- Department of Entomology, The Ohio State University, 1680 Madison Ave., Wooster, OH 44691, USA;
| | - Zsuzsanna Koncz
- Max-Planck Institut für Pflanzenzüchtungsforschung, Carl-von-Linné-Weg 10, D-50829 Köln, Germany;
| | | | - László Ötvös
- OLPE, LLC, Audubon, PA 19403-1965, USA;
- Institute of Medical Microbiology, Semmelweis University, H-1085 Budapest, Hungary
- Arrevus, Inc., Raleigh, NC 27612, USA
| | - Gyöngyi Székely
- Hungarian Department of Biology and Ecology, Faculty of Biology and Geology, Babeș-Bolyai University, 5-7 Clinicilor St., 400006 Cluj-Napoca, Romania; (E.G.); (G.S.)
- Institute for Research-Development-Innovation in Applied Natural Sciences, Babeș-Bolyai University, 30 Fântânele St., 400294 Cluj-Napoca, Romania
- Centre for Systems Biology, Biodiversity and Bioresources, Babeș-Bolyai University, 5-7 Clinicilor St., 400006 Cluj-Napoca, Romania
| | - Dávid Vozik
- Research Institute on Bioengineering, Membrane Technology and Energetics, Faculty of Engineering, University of Veszprem, H-8200 Veszprém, Hungary; or or
| | - László Makrai
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, P.O. Box 22, H-1581 Budapest, Hungary;
- Correspondence: or (A.F.); (L.M.); Tel.: +36-(30)-490-9294 (A.F.); +36-(30)-271-2513 (L.M.)
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Rémy B, Plener L, Decloquement P, Armstrong N, Elias M, Daudé D, Chabrière É. Lactonase Specificity Is Key to Quorum Quenching in Pseudomonas aeruginosa. Front Microbiol 2020; 11:762. [PMID: 32390993 PMCID: PMC7193897 DOI: 10.3389/fmicb.2020.00762] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/30/2020] [Indexed: 12/31/2022] Open
Abstract
The human opportunistic pathogen Pseudomonas aeruginosa orchestrates the expression of many genes in a cell density-dependent manner by using quorum sensing (QS). Two acyl-homoserine lactones (AHLs) are involved in QS circuits and contribute to the regulation of virulence factors production, biofilm formation, and antimicrobial sensitivity. Disrupting QS, a strategy referred to as quorum quenching (QQ) can be achieved using exogenous AHL-degrading lactonases. However, the importance of enzyme specificity on quenching efficacy has been poorly investigated. Here, we used two lactonases both targeting the signal molecules N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12 HSL) and butyryl-homoserine lactone (C4 HSL) albeit with different efficacies on C4 HSL. Interestingly, both lactonases similarly decreased AHL concentrations and comparably impacted the expression of AHL-based QS genes. However, strong variations were observed in Pseudomonas Quinolone Signal (PQS) regulation depending on the lactonase used. Both lactonases were also found to decrease virulence factors production and biofilm formation in vitro, albeit with different efficiencies. Unexpectedly, only the lactonase with lower efficacy on C4 HSL was able to inhibit P. aeruginosa pathogenicity in vivo in an amoeba infection model. Similarly, proteomic analysis revealed large variations in protein levels involved in antibiotic resistance, biofilm formation, virulence and diverse cellular mechanisms depending on the chosen lactonase. This global analysis provides evidences that QQ enzyme specificity has a significant impact on the modulation of QS-associated behavior in P. aeruginosa PA14.
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Affiliation(s)
- Benjamin Rémy
- Aix Marseille University, Institut de Recherche pour le Développement, Assistance Publique - Hôpitaux de Marseille, Microbes Evolution Phylogeny and Infections, Institut Hospitalo-Universitaire-Méditerranée Infection, Marseille, France.,Gene&GreenTK, Marseille, France
| | | | - Philippe Decloquement
- Aix Marseille University, Institut de Recherche pour le Développement, Assistance Publique - Hôpitaux de Marseille, Microbes Evolution Phylogeny and Infections, Institut Hospitalo-Universitaire-Méditerranée Infection, Marseille, France
| | - Nicholas Armstrong
- Aix Marseille University, Institut de Recherche pour le Développement, Assistance Publique - Hôpitaux de Marseille, Microbes Evolution Phylogeny and Infections, Institut Hospitalo-Universitaire-Méditerranée Infection, Marseille, France
| | - Mikael Elias
- Department of Biochemistry, Molecular Biology and Biophysics - BioTechnology Institute, University of Minnesota, St. Paul, MN, United States
| | | | - Éric Chabrière
- Aix Marseille University, Institut de Recherche pour le Développement, Assistance Publique - Hôpitaux de Marseille, Microbes Evolution Phylogeny and Infections, Institut Hospitalo-Universitaire-Méditerranée Infection, Marseille, France
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A Screen for Antibiotic Resistance Determinants Reveals a Fitness Cost of the Flagellum in Pseudomonas aeruginosa. J Bacteriol 2020; 202:JB.00682-19. [PMID: 31871033 DOI: 10.1128/jb.00682-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 12/18/2019] [Indexed: 01/09/2023] Open
Abstract
The intrinsic resistance of Pseudomonas aeruginosa to many antibiotics limits treatment options for pseudomonal infections. P. aeruginosa's outer membrane is highly impermeable and decreases antibiotic entry into the cell. We used an unbiased high-throughput approach to examine mechanisms underlying outer membrane-mediated antibiotic exclusion. Insertion sequencing (INSeq) identified genes that altered fitness in the presence of linezolid, rifampin, and vancomycin, antibiotics to which P. aeruginosa is intrinsically resistant. We reasoned that resistance to at least one of these antibiotics would depend on outer membrane barrier function, as previously demonstrated in Escherichia coli and Vibrio cholerae This approach demonstrated a critical role of the outer membrane barrier in vancomycin fitness, while efflux pumps were primary contributors to fitness in the presence of linezolid and rifampin. Disruption of flagellar assembly or function was sufficient to confer a fitness advantage to bacteria exposed to vancomycin. These findings clearly show that loss of flagellar function alone can confer a fitness advantage in the presence of an antibiotic.IMPORTANCE The cell envelopes of Gram-negative bacteria render them intrinsically resistant to many classes of antibiotics. We used insertion sequencing to identify genes whose disruption altered the fitness of a highly antibiotic-resistant pathogen, Pseudomonas aeruginosa, in the presence of antibiotics usually excluded by the cell envelope. This screen identified gene products involved in outer membrane biogenesis and homeostasis, respiration, and efflux as important contributors to fitness. An unanticipated fitness cost of flagellar assembly and function in the presence of the glycopeptide antibiotic vancomycin was further characterized. These findings have clinical relevance for individuals with cystic fibrosis who are infected with P. aeruginosa and undergo treatment with vancomycin for a concurrent Staphylococcus aureus infection.
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Sonnabend MS, Klein K, Beier S, Angelov A, Kluj R, Mayer C, Groß C, Hofmeister K, Beuttner A, Willmann M, Peter S, Oberhettinger P, Schmidt A, Autenrieth IB, Schütz M, Bohn E. Identification of Drug Resistance Determinants in a Clinical Isolate of Pseudomonas aeruginosa by High-Density Transposon Mutagenesis. Antimicrob Agents Chemother 2020; 64:e01771-19. [PMID: 31818817 PMCID: PMC7038268 DOI: 10.1128/aac.01771-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 11/25/2019] [Indexed: 01/02/2023] Open
Abstract
With the aim to identify potential new targets to restore antimicrobial susceptibility of multidrug-resistant (MDR) Pseudomonas aeruginosa isolates, we generated a high-density transposon (Tn) insertion mutant library in an MDR P. aeruginosa bloodstream isolate (isolate ID40). The depletion of Tn insertion mutants upon exposure to cefepime or meropenem was measured in order to determine the common resistome for these clinically important antipseudomonal β-lactam antibiotics. The approach was validated by clean deletions of genes involved in peptidoglycan synthesis/recycling, such as the genes for the lytic transglycosylase MltG, the murein (Mur) endopeptidase MepM1, the MurNAc/GlcNAc kinase AmgK, and the uncharacterized protein YgfB, all of which were identified in our screen as playing a decisive role in survival after treatment with cefepime or meropenem. We found that the antibiotic resistance of P. aeruginosa can be overcome by targeting usually nonessential genes that turn essential in the presence of therapeutic concentrations of antibiotics. For all validated genes, we demonstrated that their deletion leads to the reduction of ampC expression, resulting in a significant decrease in β-lactamase activity, and consequently, these mutants partly or completely lost resistance against cephalosporins, carbapenems, and acylaminopenicillins. In summary, the determined resistome may comprise promising targets for the development of drugs that may be used to restore sensitivity to existing antibiotics, specifically in MDR strains of P. aeruginosa.
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Affiliation(s)
- Michael S Sonnabend
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen (NCCT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Kristina Klein
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Sina Beier
- Center for Bioinformatics (ZBIT), Universität Tübingen, Tübingen, Germany
| | - Angel Angelov
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen (NCCT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Robert Kluj
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Department of Biology, Microbiology & Biotechnology, Universität Tübingen, Tübingen, Germany
| | - Christoph Mayer
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Department of Biology, Microbiology & Biotechnology, Universität Tübingen, Tübingen, Germany
| | - Caspar Groß
- Institut für Medizinische Genetik und Angewandte Genomik, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Kathrin Hofmeister
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Antonia Beuttner
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Matthias Willmann
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen (NCCT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Silke Peter
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen (NCCT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Philipp Oberhettinger
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Annika Schmidt
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Ingo B Autenrieth
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen (NCCT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Monika Schütz
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Erwin Bohn
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany
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Multidrug Adaptive Resistance of Pseudomonas aeruginosa Swarming Cells. Antimicrob Agents Chemother 2020; 64:AAC.01999-19. [PMID: 31844008 DOI: 10.1128/aac.01999-19] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/10/2019] [Indexed: 01/25/2023] Open
Abstract
Swarming surface motility is a complex adaptation leading to multidrug antibiotic resistance and virulence factor production in Pseudomonas aeruginosa Here, we expanded previous studies to demonstrate that under swarming conditions, P. aeruginosa PA14 is more resistant to multiple antibiotics, including aminoglycosides, β-lactams, chloramphenicol, ciprofloxacin, tetracycline, trimethoprim, and macrolides, than swimming cells, but is not more resistant to polymyxin B. We investigated the mechanism(s) of swarming-mediated antibiotic resistance by examining the transcriptomes of swarming cells and swarming cells treated with tobramycin by transcriptomics (RNA-Seq) and reverse transcriptase quantitative PCR (qRT-PCR). RNA-Seq of swarming cells (versus swimming) revealed 1,581 dysregulated genes, including 104 transcriptional regulators, two-component systems, and sigma factors, numerous upregulated virulence and iron acquisition factors, and downregulated ribosomal genes. Strain PA14 mutants in resistome genes that were dysregulated under swarming conditions were tested for their ability to swarm in the presence of tobramycin. In total, 41 mutants in genes dysregulated under swarming conditions were shown to be more resistant to tobramycin under swarming conditions, indicating that swarming-mediated tobramycin resistance was multideterminant. Focusing on two genes downregulated under swarming conditions, both prtN and wbpW mutants were more resistant to tobramycin, while the prtN mutant was additionally resistant to trimethoprim under swarming conditions; complementation of these mutants restored susceptibility. RNA-Seq of swarming cells treated with subinhibitory concentrations of tobramycin revealed the upregulation of the multidrug efflux pump MexXY and downregulation of virulence factors.
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Lau CHF, DeJong EN, Dussault F, Carrillo C, Stogios PJ, Savchenko A, Topp E. A penicillin-binding protein that can promote advanced-generation cephalosporin resistance and genome adaptation in the opportunistic pathogen Pseudomonas aeruginosa. Int J Antimicrob Agents 2020; 55:105896. [PMID: 31927042 DOI: 10.1016/j.ijantimicag.2020.105896] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/16/2019] [Accepted: 01/04/2020] [Indexed: 11/28/2022]
Abstract
A previous soil metagenomics study recovered a novel cephalosporin resistance determinant, pbpTET A6, for which the exact resistance mechanism was unclear. This study used a three-dimensional structure-guided mutagenesis approach to demonstrate that PBPTET A6 is likely to be a class A penicillin-binding protein (PBP), and that its ability to confer cephalosporin resistance is directly linked to the functional integrity of its transpeptidase (TP) catalytic core. Screening of a library of PBPTET A6 variants carrying randomly introduced point mutations revealed additional residue modifications that compromised resistance, all of which were proximal to the TP active site except one which was found in a 29-amino-acid-long superstructure (α6-α7 loop) absent in other class A PBP homologues. Based on the site-specific mutagenesis results, it is hypothesized that residue arginine-400 plays an important role in limiting the access of certain cephalosporin compounds to the enzymatic core of the TP domain of PBPTET A6. Using a combination of adaptive evolution assays and whole-genome sequencing, the potential impact of PBPTET A6 on promoting the development of resistance in the clinically significant opportunistic pathogen Pseudomonas aeruginosa was investigated. Under the selective pressure of serial ceftazidime exposures, the pbpTET A6-expressing P. aeruginosa population readily evolved by excluding a ~400-kbp chromosomal element to acquire additional resistance against cephalosporins, suggesting that PBPTET A6 has a catalytic effect on facilitating antibiotic-resistance-associated genome adaptation. Overall, the soil environment contains genes conferring resistance to critically important antibiotics by cryptic mechanisms. Understanding what impact anthropogenic activities might have on the abundance and evolution of these genes should be a priority.
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Affiliation(s)
- Calvin Ho-Fung Lau
- London Research and Development Centre, Agriculture and Agri-Food Canada, London, Ontario, Canada; Ottawa Laboratory (Carling), Canadian Food Inspection Agency, Ottawa, Ontario, Canada.
| | - Erica N DeJong
- London Research and Development Centre, Agriculture and Agri-Food Canada, London, Ontario, Canada
| | - Forest Dussault
- Ottawa Laboratory (Carling), Canadian Food Inspection Agency, Ottawa, Ontario, Canada
| | - Catherine Carrillo
- Ottawa Laboratory (Carling), Canadian Food Inspection Agency, Ottawa, Ontario, Canada
| | - Peter J Stogios
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada; Center for Structural Genomics of Infectious Diseases
| | - Alexei Savchenko
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada; Center for Structural Genomics of Infectious Diseases; Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Edward Topp
- London Research and Development Centre, Agriculture and Agri-Food Canada, London, Ontario, Canada; Department of Biology, University of Western Ontario, London, Ontario, Canada.
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Shi J, Yan Y, Links MG, Li L, Dillon JAR, Horsch M, Kusalik A. Antimicrobial resistance genetic factor identification from whole-genome sequence data using deep feature selection. BMC Bioinformatics 2019; 20:535. [PMID: 31874612 PMCID: PMC6929425 DOI: 10.1186/s12859-019-3054-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 08/26/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Antimicrobial resistance (AMR) is a major threat to global public health because it makes standard treatments ineffective and contributes to the spread of infections. It is important to understand AMR's biological mechanisms for the development of new drugs and more rapid and accurate clinical diagnostics. The increasing availability of whole-genome SNP (single nucleotide polymorphism) information, obtained from whole-genome sequence data, along with AMR profiles provides an opportunity to use feature selection in machine learning to find AMR-associated mutations. This work describes the use of a supervised feature selection approach using deep neural networks to detect AMR-associated genetic factors from whole-genome SNP data. RESULTS The proposed method, DNP-AAP (deep neural pursuit - average activation potential), was tested on a Neisseria gonorrhoeae dataset with paired whole-genome sequence data and resistance profiles to five commonly used antibiotics including penicillin, tetracycline, azithromycin, ciprofloxacin, and cefixime. The results show that DNP-AAP can effectively identify known AMR-associated genes in N. gonorrhoeae, and also provide a list of candidate genomic features (SNPs) that might lead to the discovery of novel AMR determinants. Logistic regression classifiers were built with the identified SNPs and the prediction AUCs (area under the curve) for penicillin, tetracycline, azithromycin, ciprofloxacin, and cefixime were 0.974, 0.969, 0.949, 0.994, and 0.976, respectively. CONCLUSIONS DNP-AAP can effectively identify known AMR-associated genes in N. gonorrhoeae. It also provides a list of candidate genes and intergenic regions that might lead to novel AMR factor discovery. More generally, DNP-AAP can be applied to AMR analysis of any bacterial species with genomic variants and phenotype data. It can serve as a useful screening tool for microbiologists to generate genetic candidates for further lab experiments.
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Affiliation(s)
- Jinhong Shi
- Department of Computer Science, University of Saskatchewan, 110 Science Place, Saskatoon, S7N 5C9, Canada
| | - Yan Yan
- Department of Computer Science, University of Saskatchewan, 110 Science Place, Saskatoon, S7N 5C9, Canada
| | - Matthew G Links
- Department of Computer Science, University of Saskatchewan, 110 Science Place, Saskatoon, S7N 5C9, Canada.,Department of Animal & Poultry Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, S7N 5A8, Canada
| | - Longhai Li
- Department of Mathematics and Statistics, University of Saskatchewan, 106 Wiggins Road, Saskatoon, S7N 5E6, Canada
| | - Jo-Anne R Dillon
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, S7N 5E5, Canada.,Vaccine and Infectious Disease Organization - International Vaccine Center, 120 Veterinary Rd, Saskatoon, S7N 5E3, Canada
| | - Michael Horsch
- Department of Computer Science, University of Saskatchewan, 110 Science Place, Saskatoon, S7N 5C9, Canada
| | - Anthony Kusalik
- Department of Computer Science, University of Saskatchewan, 110 Science Place, Saskatoon, S7N 5C9, Canada.
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Cabot G, Florit-Mendoza L, Sánchez-Diener I, Zamorano L, Oliver A. Deciphering β-lactamase-independent β-lactam resistance evolution trajectories in Pseudomonas aeruginosa. J Antimicrob Chemother 2019; 73:3322-3331. [PMID: 30189050 DOI: 10.1093/jac/dky364] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 08/13/2018] [Indexed: 11/14/2022] Open
Abstract
Background While resistance related to the expression of β-lactamases, such as AmpC from Pseudomonas aeruginosa, has been deeply studied, this work addresses the gap in the knowledge of other potential bacterial strategies to overcome the activity of β-lactams when β-lactamases are not expressed. Methods We analysed β-lactam resistance evolution trajectories in a WT strain and in isogenic mutants either lacking AmpC (AmpC mutant) or unable to express it (AmpG mutant), exposed to increasing concentrations of ceftazidime for 7 days in quintuplicate experiments. Characterization of evolved lineages included susceptibility profiles, whole-genome sequences, resistance mechanisms, fitness (competitive growth assays) and virulence (Caenorhabditis elegans model). Results Development of resistance was faster for the WT strain but, after 7 days, all strains reached clinical ceftazidime resistance levels. The main resistance mechanism in the WT strain was ampC overexpression, due to mutations in dacB and ampD or mpl. In contrast, ampC overexpression did not evolve in any of the AmpG lineages. Moreover, sequencing of the ΔAmpC and ΔAmpG evolved lineages revealed alternative resistance mutations (not seen in WT lineages) that included, in all cases, large (50-600 kb) deletions of specific chromosomal regions together with mutations leading to β-lactam target [ftsI (PBP3)] modification and/or the overexpression or structural modification of the efflux pump MexAB-OprM. Finally, evolved lineages from the AmpC and, especially, AmpG mutants showed a reduced fitness and virulence. Conclusions In addition to providing new insights into β-lactam resistance mechanisms and evolution, our findings should be helpful for guiding future strategies to combat P. aeruginosa infections.
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Affiliation(s)
- Gabriel Cabot
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | - Llorenç Florit-Mendoza
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | - Irina Sánchez-Diener
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | - Laura Zamorano
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | - Antonio Oliver
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
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A large-scale whole-genome comparison shows that experimental evolution in response to antibiotics predicts changes in naturally evolved clinical Pseudomonas aeruginosa. Antimicrob Agents Chemother 2019:AAC.01619-19. [PMID: 31570397 DOI: 10.1128/aac.01619-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes a wide range of acute and chronic infections. An increasing number of isolates have mutations that make them antibiotic resistant, making treatment difficult. To identify resistance-associated mutations we experimentally evolved the antibiotic sensitive strain P. aeruginosa PAO1 to become resistant to three widely used anti-pseudomonal antibiotics, ciprofloxacin, meropenem and tobramycin. Mutants could tolerate up to 2048-fold higher concentrations of antibiotic than strain PAO1. Genome sequences were determined for thirteen mutants for each antibiotic. Each mutant had between 2 and 8 mutations. For each antibiotic at least 8 genes were mutated in multiple mutants, demonstrating the genetic complexity of resistance. For all three antibiotics mutations arose in genes known to be associated with resistance, but also in genes not previously associated with resistance. To determine the clinical relevance of mutations uncovered in this study we analysed the corresponding genes in 558 isolates of P. aeruginosa from patients with chronic lung disease and in 172 isolates from the general environment. Many genes identified through experimental evolution had predicted function-altering changes in clinical isolates but not in environmental isolates, showing that mutated genes in experimentally evolved bacteria can predict those that undergo mutation during infection. Additionally, large deletions of up to 479kb arose in experimentally evolved meropenem resistant mutants and large deletions were present in 87 of the clinical isolates. These findings significantly advance understanding of antibiotic resistance in P. aeruginosa and demonstrate the validity of experimental evolution in identifying clinically-relevant resistance-associated mutations.
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Horcajada JP, Montero M, Oliver A, Sorlí L, Luque S, Gómez-Zorrilla S, Benito N, Grau S. Epidemiology and Treatment of Multidrug-Resistant and Extensively Drug-Resistant Pseudomonas aeruginosa Infections. Clin Microbiol Rev 2019; 32:32/4/e00031-19. [PMID: 31462403 PMCID: PMC6730496 DOI: 10.1128/cmr.00031-19] [Citation(s) in RCA: 425] [Impact Index Per Article: 85.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
In recent years, the worldwide spread of the so-called high-risk clones of multidrug-resistant or extensively drug-resistant (MDR/XDR) Pseudomonas aeruginosa has become a public health threat. This article reviews their mechanisms of resistance, epidemiology, and clinical impact and current and upcoming therapeutic options. In vitro and in vivo treatment studies and pharmacokinetic and pharmacodynamic (PK/PD) models are discussed. Polymyxins are reviewed as an important therapeutic option, outlining dosage, pharmacokinetics and pharmacodynamics, and their clinical efficacy against MDR/XDR P. aeruginosa infections. Their narrow therapeutic window and potential for combination therapy are also discussed. Other "old" antimicrobials, such as certain β-lactams, aminoglycosides, and fosfomycin, are reviewed here. New antipseudomonals, as well as those in the pipeline, are also reviewed. Ceftolozane-tazobactam has clinical activity against a significant percentage of MDR/XDR P. aeruginosa strains, and its microbiological and clinical data, as well as recommendations for improving its use against these bacteria, are described, as are those for ceftazidime-avibactam, which has better activity against MDR/XDR P. aeruginosa, especially strains with certain specific mechanisms of resistance. A section is devoted to reviewing upcoming active drugs such as imipenem-relebactam, cefepime-zidebactam, cefiderocol, and murepavadin. Finally, other therapeutic strategies, such as use of vaccines, antibodies, bacteriocins, anti-quorum sensing, and bacteriophages, are described as future options.
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Affiliation(s)
- Juan P Horcajada
- Service of Infectious Diseases, Hospital del Mar, Infectious Pathology and Antimicrobials Research Group, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Universitat Autònoma de Barcelona, Barcelona, Spain
- Spanish Network for Research in Infectious Diseases (REIPI), Madrid, Spain
| | - Milagro Montero
- Service of Infectious Diseases, Hospital del Mar, Infectious Pathology and Antimicrobials Research Group, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Universitat Autònoma de Barcelona, Barcelona, Spain
- Spanish Network for Research in Infectious Diseases (REIPI), Madrid, Spain
| | - Antonio Oliver
- Service of Microbiology, Hospital Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | - Luisa Sorlí
- Service of Infectious Diseases, Hospital del Mar, Infectious Pathology and Antimicrobials Research Group, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Universitat Pompeu Fabra, Barcelona, Spain
- Spanish Network for Research in Infectious Diseases (REIPI), Madrid, Spain
| | - Sònia Luque
- Service of Pharmacy, Hospital del Mar, Infectious Pathology and Antimicrobials Research Group, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Silvia Gómez-Zorrilla
- Service of Infectious Diseases, Hospital del Mar, Infectious Pathology and Antimicrobials Research Group, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Universitat Pompeu Fabra, Barcelona, Spain
- Spanish Network for Research in Infectious Diseases (REIPI), Madrid, Spain
| | - Natividad Benito
- Infectious Diseases Unit, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomèdica Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Santiago Grau
- Service of Pharmacy, Hospital del Mar, Infectious Pathology and Antimicrobials Research Group, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Universitat Autònoma de Barcelona, Barcelona, Spain
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Clark ST, Guttman DS, Hwang DM. Diversification of Pseudomonas aeruginosa within the cystic fibrosis lung and its effects on antibiotic resistance. FEMS Microbiol Lett 2019; 365:4834010. [PMID: 29401362 DOI: 10.1093/femsle/fny026] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 01/30/2018] [Indexed: 12/13/2022] Open
Abstract
The evolution and diversification of bacterial pathogens within human hosts represent potential barriers to the diagnosis and treatment of life-threatening infections. Tremendous genetic and phenotypic diversity is characteristic of host adaptation in strains of Pseudomonas aeruginosa that infect the airways of individuals with chronic lung diseases and prove to be extremely difficult to eradicate. In this MiniReview, we examine recent advances in understanding within-host diversity and antimicrobial resistance in P. aeruginosa populations from the lower airways of individuals with the fatal genetic disease cystic fibrosis and the potential impacts that this diversity may have on detecting and interpreting antimicrobial susceptibility within these populations.
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Affiliation(s)
- Shawn T Clark
- Toronto General Hospital Research Institute, University Health Network, 101 College Street, PMCRT - MaRS Centre, Toronto, Ontario M5G 1L7, Canada
| | - David S Guttman
- Department of Cell & Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario M5S 3G5, Canada.,Centre for the Analysis of Genome Evolution & Function, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada
| | - David M Hwang
- Toronto General Hospital Research Institute, University Health Network, 101 College Street, PMCRT - MaRS Centre, Toronto, Ontario M5G 1L7, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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Li Z, Wang Y, Li X, Lin Z, Lin Y, Srinivasan R, Lin X. The characteristics of antibiotic resistance and phenotypes in 29 outer‐membrane protein mutant strains inAeromonas hydrophila. Environ Microbiol 2019; 21:4614-4628. [DOI: 10.1111/1462-2920.14761] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 07/22/2019] [Accepted: 07/25/2019] [Indexed: 01/18/2023]
Affiliation(s)
- Zeqi Li
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring (School of Life Sciences)Fujian Agriculture and Forestry University) Fuzhou China
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University)Fujian Province University Fuzhou China
| | - Yuqian Wang
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring (School of Life Sciences)Fujian Agriculture and Forestry University) Fuzhou China
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University)Fujian Province University Fuzhou China
| | - Xiaoyan Li
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring (School of Life Sciences)Fujian Agriculture and Forestry University) Fuzhou China
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University)Fujian Province University Fuzhou China
| | - Zhenping Lin
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring (School of Life Sciences)Fujian Agriculture and Forestry University) Fuzhou China
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University)Fujian Province University Fuzhou China
| | - Yuexu Lin
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring (School of Life Sciences)Fujian Agriculture and Forestry University) Fuzhou China
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University)Fujian Province University Fuzhou China
| | - Ramanathan Srinivasan
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring (School of Life Sciences)Fujian Agriculture and Forestry University) Fuzhou China
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University)Fujian Province University Fuzhou China
| | - Xiangmin Lin
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring (School of Life Sciences)Fujian Agriculture and Forestry University) Fuzhou China
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University)Fujian Province University Fuzhou China
- Key Laboratory of Marine Biotechnology of Fujian ProvinceInstitute of Oceanology, Fujian Agriculture and Forestry University Fuzhou 350002 China
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Harrison LB, Fowler RC, Abdalhamid B, Selmecki A, Hanson ND. lptG contributes to changes in membrane permeability and the emergence of multidrug hypersusceptibility in a cystic fibrosis isolate of Pseudomonas aeruginosa. Microbiologyopen 2019; 8:e844. [PMID: 30977288 PMCID: PMC6854846 DOI: 10.1002/mbo3.844] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/14/2019] [Accepted: 03/15/2019] [Indexed: 01/17/2023] Open
Abstract
PURPOSE In the lungs of cystic fibrosis patients, Pseudomonas aeruginosa is exposed to a myriad of antibiotics leading to alterations in antibiotic susceptibility. This study identifies mutations resulting in hypersusceptibility in isogenic mutants of a P. aeruginosa clinical isolate, PA34. METHODS PA34 was exposed to subinhibitory concentrations of doripenem or meropenem during growth to mid-log phase. Antibiotic susceptibility of surviving colonies was determined by agar dilution. Two carbapenem-resistant colonies hypersusceptible to non-carbapenem antibiotics were selected for further analysis. Antibiotic resistance gene expression was evaluated by RT-rtPCR and OprD production by SDS-PAGE. PA34 and isogenic mutants were evaluated with whole genome sequencing. Sequence variants were confirmed by Sanger sequencing, and cognate genes in eight carbapenem-resistant clinical isolates hypersusceptible to non-carbapenem antibiotics were sequenced. Lipopolysaccharide preparations of PA34 and hypersusceptible mutants were evaluated with ProQ-Emerald stain. RESULTS Isogenic mutants showed 4- to 8-fold MIC increase for imipenem, meropenem, and doripenem. However, they were hypersusceptible (≥4-fold MIC decrease) to aminoglycosides, fluoroquinolones, and non-carbapenem β-lactams. Expression of ampC or mex-opr efflux pumps was unchanged, but OprD production was decreased. Mutations causing Q86H AlgU and G77C LptG amino acid substitutions and nonsense mutations within OprD were observed in both mutants. Lipopolysaccharide modifications were observed between isogenic mutants and PA34. Non-synonymous mutations in LptF or LptG were observed in 6/8 hypersusceptible clinical isolates resistant to carbapenem antibiotics. CONCLUSION Evaluation of hypersusceptible mutants identified the association between lptG and a hypersusceptible phenotype. Modifications in lipopolysaccharide profiles suggests LptG modification interferes with lipopolysaccharide transport and contributes to hypersusceptibility.
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Affiliation(s)
- Lucas B Harrison
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska
| | - Randal C Fowler
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska
| | - Baha Abdalhamid
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha
| | - Anna Selmecki
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska
| | - Nancy D Hanson
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska
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Santhakumar K, Viswanath V. Novel Methods for Efficacy Testing of Disinfectants – Part I. TENSIDE SURFACT DET 2019. [DOI: 10.3139/113.110597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Abstract
The pathogens which are the effective transmitters of various infections pose a serious problem in restraining their interference in maintaining a sterile environment. The practical applicability of traditional methods of disinfection is restricted due to their cumbersomeness, toxic product generation, and cost-effectiveness. Therefore, the objective of the current review is to elaborate the efficacies and limitations of various novel disinfectants that can show their activity in a few minutes of treatment. The expected outcome would be feasibility for selection of a favorable disinfectant through various technologies that can generate uniform results and form a basis for the true estimation required parameters. Hence, the current paper ends with the consideration of unique new techniques that distinguishes their simplicity, safety, and efficacy in generating a sterile environment.
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Affiliation(s)
| | - Valikala Viswanath
- Carbon dioxide Research and Green Technologies Center , VIT University, Tamil Nadu , India
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Dunphy LJ, Yen P, Papin JA. Integrated Experimental and Computational Analyses Reveal Differential Metabolic Functionality in Antibiotic-Resistant Pseudomonas aeruginosa. Cell Syst 2019; 8:3-14.e3. [PMID: 30611675 DOI: 10.1016/j.cels.2018.12.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/08/2018] [Accepted: 12/04/2018] [Indexed: 12/13/2022]
Abstract
Metabolic adaptations accompanying the development of antibiotic resistance in bacteria remain poorly understood. To study this relationship, we profiled the growth of lab-evolved antibiotic-resistant lineages of the opportunistic pathogen Pseudomonas aeruginosa across 190 unique carbon sources. Our data revealed that the evolution of antibiotic resistance resulted in systems-level changes to growth dynamics and metabolic phenotype. A genome-scale metabolic network reconstruction of P. aeruginosa was paired with whole-genome sequencing data to predict genes contributing to observed changes in metabolism. We experimentally validated computational predictions to identify mutations in resistant P. aeruginosa affecting loss of catabolic function. Finally, we found a shared metabolic phenotype between lab-evolved P. aeruginosa and clinical isolates with similar mutational landscapes. Our results build upon previous knowledge of antibiotic-induced metabolic adaptation and provide a framework for the identification of metabolic limitations in antibiotic-resistant pathogens.
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Affiliation(s)
- Laura J Dunphy
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Phillip Yen
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Jason A Papin
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA; Department of Medicine, Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, USA; Department of Biochemistry & Molecular Genetics, University of Virginia, Charlottesville, VA, USA.
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Amato DN, Amato DV, Adewunmi Y, Mavrodi OV, Parsons KH, Swilley SN, Braasch DA, Walker WD, Mavrodi DV, Patton DL. Using Aldehyde Synergism To Direct the Design of Degradable Pro-Antimicrobial Networks. ACS APPLIED BIO MATERIALS 2018; 1:1983-1991. [DOI: 10.1021/acsabm.8b00500] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Broad-Spectrum Adaptive Antibiotic Resistance Associated with Pseudomonas aeruginosa Mucin-Dependent Surfing Motility. Antimicrob Agents Chemother 2018; 62:AAC.00848-18. [PMID: 29967020 DOI: 10.1128/aac.00848-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 06/22/2018] [Indexed: 02/04/2023] Open
Abstract
Surfing motility is a novel form of surface adaptation exhibited by the nosocomial pathogen Pseudomonas aeruginosa in the presence of the glycoprotein mucin, which is found in high abundance at mucosal surfaces, especially those of the lungs of cystic fibrosis and bronchiectasis patients. Here, we investigated the adaptive antibiotic resistance of P. aeruginosa under conditions in which surfing occurs compared that in to cells undergoing swimming. P. aeruginosa surfing cells were significantly more resistant to several classes of antibiotics, including aminoglycosides, carbapenems, polymyxins, and fluoroquinolones. This was confirmed by incorporation of antibiotics into growth medium, which revealed a concentration-dependent inhibition of surfing motility that occurred at concentrations much higher than those needed to inhibit swimming. To investigate the basis of resistance, transcriptome sequencing (RNA-Seq) was performed and revealed that surfing influenced the expression of numerous genes. Included among genes dysregulated under surfing conditions were multiple genes from the Pseudomonas resistome; these genes are known to affect antibiotic resistance when mutated. Screening transposon mutants in these surfing-dysregulated resistome genes revealed that several of these mutants exhibited changes in susceptibility to one or more antibiotics under surfing conditions, consistent with a contribution to the observed adaptive resistance. In particular, several mutants in resistome genes, including armR, recG, atpB, clpS, nuoB, and certain hypothetical genes, such as PA5130, PA3576, and PA4292, showed contributions to broad-spectrum resistance under surfing conditions and could be complemented by their respective cloned genes. Therefore, we propose that surfing adaption led to extensive multidrug adaptive resistance as a result of the collective dysregulation of diverse genes.
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Nøhr-Meldgaard K, Ovsepian A, Ingmer H, Vestergaard M. Resveratrol enhances the efficacy of aminoglycosides against Staphylococcus aureus. Int J Antimicrob Agents 2018; 52:390-396. [PMID: 29906565 DOI: 10.1016/j.ijantimicag.2018.06.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 04/17/2018] [Accepted: 06/02/2018] [Indexed: 01/04/2023]
Abstract
Development of new antibiotics is costly and time-consuming, and therefore increasing the efficacy of conventional antibiotics is extremely attractive. For the human pathogen, Staphylococcus aureus, inactivation of the ATP synthase increases its susceptibility to gentamicin (an aminoglycoside) 16-fold. Aminoglycosides are rarely used as monotherapy against S. aureus due to the risk of development of resistance and toxic effects. This study explored the possibility of enhancing the efficacy of aminoglycosides against S. aureus and other Gram-positive pathogens by inhibiting the ATP synthase with resveratrol, a polyphenolic ATP synthase inhibitor that is commonly used as a dietary supplement. Co-administration of subinhibitory concentrations of resveratrol increased the activity of aminoglycosides, including gentamicin, kanamycin, neomycin, streptomycin and tobramycin, up to 32-fold against S. aureus, while the effect was lower (2-4-fold reduction in minimum inhibitory concentration) for other Gram-positive pathogens (i.e. Staphylococcus epidermidis, Enterococcus faecium and Enterococcus faecalis). The mechanism by which resveratrol increases the efficacy of aminoglycosides appears to be unrelated to membrane hyperpolarization and disruption of membrane integrity, which have been associated previously with increased aminoglycoside susceptibility. These results demonstrate that inhibition of the ATP synthase increases the efficacy of aminoglycosides against important Gram-positive pathogens, and the ATP synthase should be explored further as a target that may extend the clinical applicability of aminoglycosides.
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Affiliation(s)
- Katrine Nøhr-Meldgaard
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Armen Ovsepian
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.
| | - Martin Vestergaard
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
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López-Causapé C, Cabot G, Del Barrio-Tofiño E, Oliver A. The Versatile Mutational Resistome of Pseudomonas aeruginosa. Front Microbiol 2018; 9:685. [PMID: 29681898 PMCID: PMC5897538 DOI: 10.3389/fmicb.2018.00685] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 03/23/2018] [Indexed: 12/11/2022] Open
Abstract
One of the most striking features of Pseudomonas aeruginosa is its outstanding capacity for developing antimicrobial resistance to nearly all available antipseudomonal agents through the selection of chromosomal mutations, leading to the failure of the treatment of severe hospital-acquired or chronic infections. Recent whole-genome sequencing (WGS) data obtained from in vitro assays on the evolution of antibiotic resistance, in vivo monitoring of antimicrobial resistance development, analysis of sequential cystic fibrosis isolates, and characterization of widespread epidemic high-risk clones have provided new insights into the evolutionary dynamics and mechanisms of P. aeruginosa antibiotic resistance, thus motivating this review. Indeed, the analysis of the WGS mutational resistome has proven to be useful for understanding the evolutionary dynamics of classical resistance pathways and to describe new mechanisms for the majority of antipseudomonal classes, including β-lactams, aminoglycosides, fluoroquinolones, or polymixins. Beyond addressing a relevant scientific question, the analysis of the P. aeruginosa mutational resistome is expected to be useful, together with the analysis of the horizontally-acquired resistance determinants, for establishing the antibiotic resistance genotype, which should correlate with the antibiotic resistance phenotype and as such, it should be useful for the design of therapeutic strategies and for monitoring the efficacy of administered antibiotic treatments. However, further experimental research and new bioinformatics tools are still needed to overcome the interpretation limitations imposed by the complex interactions (including those leading to collateral resistance or susceptibility) between the 100s of genes involved in the mutational resistome, as well as the frequent difficulties for differentiating relevant mutations from simple natural polymorphisms.
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Affiliation(s)
- Carla López-Causapé
- Servicio de Microbiología y Unidad de Investigación, Hospital Universitari Son Espases, Institut d'Investigació Sanitaria Illes Balears, Palma de Mallorca, Spain
| | - Gabriel Cabot
- Servicio de Microbiología y Unidad de Investigación, Hospital Universitari Son Espases, Institut d'Investigació Sanitaria Illes Balears, Palma de Mallorca, Spain
| | - Ester Del Barrio-Tofiño
- Servicio de Microbiología y Unidad de Investigación, Hospital Universitari Son Espases, Institut d'Investigació Sanitaria Illes Balears, Palma de Mallorca, Spain
| | - Antonio Oliver
- Servicio de Microbiología y Unidad de Investigación, Hospital Universitari Son Espases, Institut d'Investigació Sanitaria Illes Balears, Palma de Mallorca, Spain
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Vogwill T, Phillips RL, Gifford DR, MacLean RC. Divergent evolution peaks under intermediate population bottlenecks during bacterial experimental evolution. Proc Biol Sci 2017; 283:rspb.2016.0749. [PMID: 27466449 PMCID: PMC4971204 DOI: 10.1098/rspb.2016.0749] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 07/04/2016] [Indexed: 12/30/2022] Open
Abstract
There is growing evidence that parallel molecular evolution is common, but its causes remain poorly understood. Demographic parameters such as population bottlenecks are predicted to be major determinants of parallelism. Here, we test the hypothesis that bottleneck intensity shapes parallel evolution by elucidating the genomic basis of adaptation to antibiotic-supplemented media in hundreds of populations of the bacterium Pseudomonas fluorescens Pf0-1. As expected, bottlenecking decreased the rate of phenotypic and molecular adaptation. Surprisingly, bottlenecking had no impact on the likelihood of parallel adaptive molecular evolution at a genome-wide scale. However, bottlenecking had a profound impact on the genes involved in antibiotic resistance. Specifically, under either intense or weak bottlenecking, resistance predominantly evolved by strongly beneficial mutations which provide high levels of antibiotic resistance. In contrast with intermediate bottlenecking regimes, resistance evolved by a greater diversity of genetic mechanisms, significantly reducing the observed levels of parallel genetic evolution. Our results demonstrate that population bottlenecking can be a major predictor of parallel evolution, but precisely how may be more complex than many simple theoretical predictions.
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Affiliation(s)
- Tom Vogwill
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Robyn L Phillips
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Danna R Gifford
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - R Craig MacLean
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
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Evolved Aztreonam Resistance Is Multifactorial and Can Produce Hypervirulence in Pseudomonas aeruginosa. mBio 2017; 8:mBio.00517-17. [PMID: 29089424 PMCID: PMC5666152 DOI: 10.1128/mbio.00517-17] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
While much attention has been focused on acquired antibiotic resistance genes, chromosomal mutations may be most important in chronic infections where isolated, persistently infecting lineages experience repeated antibiotic exposure. Here, we used experimental evolution and whole-genome sequencing to investigate chromosomally encoded mutations causing aztreonam resistance in Pseudomonas aeruginosa and characterized the secondary consequences of resistance development. We identified 19 recurrently mutated genes associated with aztreonam resistance. The most frequently observed mutations affected negative transcriptional regulators of the mexAB-oprM efflux system and the target of aztreonam, ftsI. While individual mutations conferred modest resistance gains, high-level resistance (1,024 µg/ml) was achieved through the accumulation of multiple variants. Despite being largely stable when strains were passaged in the absence of antibiotics, aztreonam resistance was associated with decreased in vitro growth rates, indicating an associated fitness cost. In some instances, evolved aztreonam-resistant strains exhibited increased resistance to structurally unrelated antipseudomonal antibiotics. Surprisingly, strains carrying evolved mutations which affected negative regulators of mexAB-oprM (mexR and nalD) demonstrated enhanced virulence in a murine pneumonia infection model. Mutations in these genes, and other genes that we associated with aztreonam resistance, were common in P. aeruginosa isolates from chronically infected patients with cystic fibrosis. These findings illuminate mechanisms of P. aeruginosa aztreonam resistance and raise the possibility that antibiotic treatment could inadvertently select for hypervirulence phenotypes. Inhaled aztreonam is a relatively new antibiotic which is being increasingly used to treat cystic fibrosis patients with Pseudomonas aeruginosa airway infections. As for all antimicrobial agents, bacteria can evolve resistance that decreases the effectiveness of the drug; however, the mechanisms and consequences of aztreonam resistance are incompletely understood. Here, using experimental evolution, we have cataloged spontaneous mutations conferring aztreonam resistance and have explored their effects. We found that a diverse collection of genes contributes to aztreonam resistance, each with a small but cumulative effect. Surprisingly, we found that selection for aztreonam resistance mutations could confer increased resistance to other antibiotics and promote hypervirulence in a mouse infection model. Our study reveals inherent mechanisms of aztreonam resistance and indicates that aztreonam exposure can have unintended secondary effects.
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47
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López-Causapé C, Oliver A. Insights into the evolution of the mutational resistome of Pseudomonas aeruginosa in cystic fibrosis. Future Microbiol 2017; 12:1445-1448. [PMID: 29068237 DOI: 10.2217/fmb-2017-0197] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Carla López-Causapé
- Servicio de Microbiología & Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Illes Balears (IdISBa), Palma de Mallorca, Spain
| | - Antonio Oliver
- Servicio de Microbiología & Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Illes Balears (IdISBa), Palma de Mallorca, Spain
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Chen F, Chen G, Liu Y, Jin Y, Cheng Z, Liu Y, Yang L, Jin S, Wu W. Pseudomonas aeruginosa Oligoribonuclease Contributes to Tolerance to Ciprofloxacin by Regulating Pyocin Biosynthesis. Antimicrob Agents Chemother 2017; 61:e02256-16. [PMID: 28052848 PMCID: PMC5328516 DOI: 10.1128/aac.02256-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 12/21/2016] [Indexed: 01/17/2023] Open
Abstract
Bacterial oligoribonuclease (Orn) is a conserved 3'-to-5' exonuclease. In Pseudomonas aeruginosa, it has been demonstrated that Orn plays a major role in the hydrolysis of pGpG, which is required for cyclic-di-GMP homeostasis. Meanwhile, Orn is involved in the degradation of nanoRNAs, which can alter global gene expression by serving as transcription initiation primers. Previously, we found that Orn is required for the type III secretion system and pathogenesis of P. aeruginosa, indicating a role of Orn in the bacterial response to environmental stimuli. Here we report that Orn is required for the tolerance of P. aeruginosa to ciprofloxacin. Transcriptome analysis of an orn mutant revealed the upregulation of pyocin biosynthesis genes. Mutation of genes involved in pyocin biosynthesis in the background of an orn mutant restored bacterial tolerance to ciprofloxacin. We further demonstrate that the upregulation of pyocin biosynthesis genes is due to RecA-mediated autoproteolysis of PrtR, which is the major negative regulator of pyocin biosynthesis genes. In addition, the SOS response genes were upregulated in the orn mutant, indicating a DNA damage stress. Therefore, our results revealed a novel role of Orn in bacterial tolerance to ciprofloxacin.
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Affiliation(s)
- Fei Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Gukui Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yiwei Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yang Liu
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Division of Structural Biology and Biochemistry, Nanyang Technological University, Singapore, Singapore
| | - Liang Yang
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Division of Structural Biology and Biochemistry, Nanyang Technological University, Singapore, Singapore
| | - Shouguang Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
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Vestergaard M, Leng B, Haaber J, Bojer MS, Vegge CS, Ingmer H. Genome-Wide Identification of Antimicrobial Intrinsic Resistance Determinants in Staphylococcus aureus. Front Microbiol 2016; 7:2018. [PMID: 28066345 PMCID: PMC5165250 DOI: 10.3389/fmicb.2016.02018] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/02/2016] [Indexed: 11/24/2022] Open
Abstract
The emergence of antimicrobial resistance severely threatens our ability to treat bacterial infections. While acquired resistance has received considerable attention, relatively little is known of intrinsic resistance that allows bacteria to naturally withstand antimicrobials. Gene products that confer intrinsic resistance to antimicrobial agents may be explored for alternative antimicrobial therapies, by potentiating the efficacy of existing antimicrobials. In this study, we identified the intrinsic resistome to a broad spectrum of antimicrobials in the human pathogen, Staphylococcus aureus. We screened the Nebraska Transposon Mutant Library of 1920 single-gene inactivations in S. aureus strain JE2, for increased susceptibility to the anti-staphylococcal antimicrobials (ciprofloxacin, oxacillin, linezolid, fosfomycin, daptomycin, mupirocin, vancomycin, and gentamicin). Sixty-eight mutants were confirmed by E-test to display at least twofold increased susceptibility to one or more antimicrobial agents. The majority of the identified genes have not previously been associated with antimicrobial susceptibility in S. aureus. For example, inactivation of genes encoding for subunits of the ATP synthase, atpA, atpB, atpG and atpH, reduced the minimum inhibitory concentration (MIC) of gentamicin 16-fold. To elucidate the potential of the screen, we examined treatment efficacy in the Galleria mellonella infection model. Gentamicin efficacy was significantly improved, when treating larvae infected with the atpA mutant compared to wild type cells with gentamicin at a clinically relevant concentration. Our results demonstrate that many gene products contribute to the intrinsic antimicrobial resistance of S. aureus. Knowledge of these intrinsic resistance determinants provides alternative targets for compounds that may potentiate the efficacy of existing antimicrobial agents against this important pathogen.
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Affiliation(s)
- Martin Vestergaard
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen Frederiksberg, Denmark
| | - Bingfeng Leng
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen Frederiksberg, Denmark
| | - Jakob Haaber
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen Frederiksberg, Denmark
| | - Martin S Bojer
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen Frederiksberg, Denmark
| | - Christina S Vegge
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen Frederiksberg, Denmark
| | - Hanne Ingmer
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen Frederiksberg, Denmark
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50
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A PhoPQ-Regulated ABC Transporter System Exports Tetracycline in Pseudomonas aeruginosa. Antimicrob Agents Chemother 2016; 60:3016-24. [PMID: 26953208 DOI: 10.1128/aac.02986-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/29/2016] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas aeruginosa is an important human pathogen whose infections are difficult to treat due to its high intrinsic resistance to many antibiotics. Here, we show that the disruption of PA4456, encoding the ATP binding component of a putative ATP-binding cassette (ABC) transporter, increased the bacterium's susceptible to tetracycline and other antibiotics or toxic chemicals. Fluorescence spectroscopy and antibiotic accumulation tests showed that the interruption of the ABC transporter caused increased intracellular accumulation of tetracycline, demonstrating a role of the ABC transporter in tetracycline expulsion. Site-directed mutagenesis proved that the conserved residues of E170 in the Walker B motif and H203 in the H-loop, which are important for ATP hydrolysis, were essential for the function of PA4456. Through a genome-wide search, the PhoPQ two-component system was identified as a regulator of the computationally predicted PA4456-4452 operon that encodes the ABC transporter system. A >5-fold increase of the expression of this operon was observed in the phoQ mutant. The results obtained also show that the expression of the phzA1B1C1D1E1 operon and the production of pyocyanin were significantly higher in the ABC transporter mutant, signifying a connection between the ABC transporter and pyocyanin production. These results indicated that the PhoPQ-regulated ABC transporter is associated with intrinsic resistance to antibiotics and other adverse compounds in P. aeruginosa, probably by extruding them out of the cell.
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