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Chick HM, Rees ME, Lewis ML, Williams LK, Bodger O, Harris LG, Rushton S, Wilkinson TS. Using the Traditional Ex Vivo Whole Blood Model to Discriminate Bacteria by Their Inducible Host Responses. Biomedicines 2024; 12:724. [PMID: 38672079 PMCID: PMC11047930 DOI: 10.3390/biomedicines12040724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 04/28/2024] Open
Abstract
Whole blood models are rapid and versatile for determining immune responses to inflammatory and infectious stimuli, but they have not been used for bacterial discrimination. Staphylococcus aureus, S. epidermidis and Escherichia coli are the most common causes of invasive disease, and rapid testing strategies utilising host responses remain elusive. Currently, immune responses can only discriminate between bacterial 'domains' (fungi, bacteria and viruses), and very few studies can use immune responses to discriminate bacteria at the species and strain level. Here, whole blood was used to investigate the relationship between host responses and bacterial strains. Results confirmed unique temporal profiles for the 10 parameters studied: IL-6, MIP-1α, MIP-3α, IL-10, resistin, phagocytosis, S100A8, S100A8/A9, C5a and TF3. Pairwise analysis confirmed that IL-6, resistin, phagocytosis, C5a and S100A8/A9 could be used in a discrimination scheme to identify to the strain level. Linear discriminant analysis (LDA) confirmed that (i) IL-6, MIP-3α and TF3 could predict genera with 95% accuracy; (ii) IL-6, phagocytosis, resistin and TF3 could predict species at 90% accuracy and (iii) phagocytosis, S100A8 and IL-10 predicted strain at 40% accuracy. These data are important because they confirm the proof of concept that host biomarker panels could be used to identify bacterial pathogens.
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Affiliation(s)
- Heather M. Chick
- Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School, Swansea SA2 8PP, UK; (H.M.C.); (M.E.R.); (M.L.L.); (L.K.W.); (L.G.H.)
| | - Megan E. Rees
- Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School, Swansea SA2 8PP, UK; (H.M.C.); (M.E.R.); (M.L.L.); (L.K.W.); (L.G.H.)
| | - Matthew L. Lewis
- Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School, Swansea SA2 8PP, UK; (H.M.C.); (M.E.R.); (M.L.L.); (L.K.W.); (L.G.H.)
| | - Lisa K. Williams
- Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School, Swansea SA2 8PP, UK; (H.M.C.); (M.E.R.); (M.L.L.); (L.K.W.); (L.G.H.)
- Department of Animal and Agriculture, Hartpury University, Hartpury, Gloucestershire GL19 3BE, UK
| | - Owen Bodger
- Patient and Population Health an Informatics Research, Swansea University Medical School, Swansea SA2 8PP, UK;
| | - Llinos G. Harris
- Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School, Swansea SA2 8PP, UK; (H.M.C.); (M.E.R.); (M.L.L.); (L.K.W.); (L.G.H.)
| | - Steven Rushton
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK;
| | - Thomas S. Wilkinson
- Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School, Swansea SA2 8PP, UK; (H.M.C.); (M.E.R.); (M.L.L.); (L.K.W.); (L.G.H.)
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2
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Brown S, Evans SJ, Burgum MJ, Meldrum K, Herridge J, Akinbola B, Harris LG, Jenkins R, Doak SH, Clift MJD, Wilkinson TS. An In Vitro Model to Assess Early Immune Markers Following Co-Exposure of Epithelial Cells to Carbon Black (Nano)Particles in the Presence of S. aureus: A Role for Stressed Cells in Toxicological Testing. Biomedicines 2024; 12:128. [PMID: 38255233 PMCID: PMC10813740 DOI: 10.3390/biomedicines12010128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 12/21/2023] [Accepted: 12/25/2023] [Indexed: 01/24/2024] Open
Abstract
The exposure of human lung and skin to carbon black (CB) is continuous due to its widespread applications. Current toxicological testing uses 'healthy' cellular systems; however, questions remain whether this mimics the everyday stresses that human cells are exposed to, including infection. Staphylococcus aureus lung and skin infections remain prevalent in society, and include pneumonia and atopic dermatitis, respectively, but current in vitro toxicological testing does not consider infection stress. Therefore, investigating the effects of CB co-exposure in 'stressed' infected epithelial cells in vitro may better approximate true toxicity. This work aims to study the impact of CB exposure during Staphylococcus aureus infection stress in A549 (lung) and HaCaT (skin) epithelial cells. Physicochemical characterisation of CB confirmed its dramatic polydispersity and potential to aggregate. CB significantly inhibited S. aureus growth in cell culture media. CB did not induce cytokines or antimicrobial peptides from lung and skin epithelial cells, when given alone, but did reduce HaCaT and A549 cell viability to 55% and 77%, respectively. In contrast, S. aureus induced a robust interleukin (IL)-8 response in both lung and skin epithelial cells. IL-6 and human beta defensin (hβD)-2 could only be detected when cells were stimulated with S. aureus with no decreases in cell viability. However, co-exposure to CB (100 µg/mL) and S. aureus resulted in significant inhibition of IL-8 (compared to S. aureus alone) without further reduction in cell viability. Furthermore, the same co-exposure induced significantly more hβD-2 (compared to S. aureus alone). This work confirms that toxicological testing in healthy versus stressed cells gives significantly different responses. This has significant implications for toxicological testing and suggests that cell stresses (including infection) should be included in current models to better represent the diversity of cell viabilities found in lung and skin within a general population. This model will have significant application when estimating CB exposure in at-risk groups, such as factory workers, the elderly, and the immunocompromised.
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Affiliation(s)
- Scott Brown
- Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School (SUMS), Swansea SA2 8PP, UK
| | - Stephen J. Evans
- In Vitro Toxicology Group, Institute of Life Science, Swansea University Medical School (SUMS), Swansea SA2 8PP, UK (M.J.D.C.)
| | - Michael J. Burgum
- In Vitro Toxicology Group, Institute of Life Science, Swansea University Medical School (SUMS), Swansea SA2 8PP, UK (M.J.D.C.)
| | - Kirsty Meldrum
- In Vitro Toxicology Group, Institute of Life Science, Swansea University Medical School (SUMS), Swansea SA2 8PP, UK (M.J.D.C.)
| | - Jack Herridge
- Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School (SUMS), Swansea SA2 8PP, UK
| | - Blessing Akinbola
- Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School (SUMS), Swansea SA2 8PP, UK
| | - Llinos G. Harris
- Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School (SUMS), Swansea SA2 8PP, UK
| | - Rowena Jenkins
- Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School (SUMS), Swansea SA2 8PP, UK
| | - Shareen H. Doak
- In Vitro Toxicology Group, Institute of Life Science, Swansea University Medical School (SUMS), Swansea SA2 8PP, UK (M.J.D.C.)
| | - Martin J. D. Clift
- In Vitro Toxicology Group, Institute of Life Science, Swansea University Medical School (SUMS), Swansea SA2 8PP, UK (M.J.D.C.)
| | - Thomas S. Wilkinson
- Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School (SUMS), Swansea SA2 8PP, UK
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3
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Alio I, Moll R, Hoffmann T, Mamat U, Schaible UE, Pappenfort K, Alawi M, Schie M, Thünauer R, Stamm J, Rohde H, Streit WR. Stenotrophomonas maltophilia affects the gene expression profiles of the major pathogens Pseudomonas aeruginosa and Staphylococcus aureus in an in vitro multispecies biofilm model. Microbiol Spectr 2023; 11:e0085923. [PMID: 37819084 PMCID: PMC10714729 DOI: 10.1128/spectrum.00859-23] [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: 03/02/2023] [Accepted: 08/21/2023] [Indexed: 10/13/2023] Open
Abstract
IMPORTANCE In the past, studies have focused on bacterial pathogenicity in mono-species infections, in part ignoring the clinical relevance of diseases caused by more than one pathogen (i.e., polymicrobial infections). However, it is now common knowledge that multiple bacteria species are often involved in the course of an infection. For treatment of such infections, it is absolutely important to understand the dynamics of species interactions at possible infection sites and the molecular mechanisms behind these interactions. Here, we studied the impact of Stenotrophomonas maltophilia on its commensals Pseudomonas aeruginosa and Staphylococcus aureus in multispecies biofilms. We analyzed the 3D structural architectures of dual- and triple-species biofilms, niche formation within the biofilms, and the interspecies interactions on a molecular level. RNAseq data identified key genes involved in multispecies biofilm formation and interaction as potential drug targets for the clinical combat of multispecies infection with these major pathogens.
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Affiliation(s)
- Ifey Alio
- Department of Microbiology and Biotechnology, University Hamburg, Hamburg, Germany
| | - Raphael Moll
- Department of Microbiology and Biotechnology, University Hamburg, Hamburg, Germany
| | - Tim Hoffmann
- Department of Microbiology and Biotechnology, University Hamburg, Hamburg, Germany
| | - Uwe Mamat
- Cellular Microbiology, Priority Research Area Infections, Research Center Borstel, Leibniz Lung Center,Leibniz Research Alliance Infection , Borstel Gemany, Borstel, Germany
| | - Ulrich E. Schaible
- Cellular Microbiology, Priority Research Area Infections, Research Center Borstel, Leibniz Lung Center,Leibniz Research Alliance Infection , Borstel Gemany, Borstel, Germany
| | - Kai Pappenfort
- Institute of Microbiology, Friedrich Schiller University of Jena, Jena, Germany
| | - Malik Alawi
- Bioinformatics Core, UKE Hamburg, Hamburg, Germany
| | - Marcel Schie
- LIV, Leibniz Institute of Experimental Virology, Hamburg, Germany
| | - Roland Thünauer
- LIV, Leibniz Institute of Experimental Virology, Hamburg, Germany
| | - Johanna Stamm
- Institute for Medical Microbiology, Virology and Hygiene, UKE, Eppendorf, Hamburg, Germany
| | - Holger Rohde
- Institute for Medical Microbiology, Virology and Hygiene, UKE, Eppendorf, Hamburg, Germany
| | - Wolfgang R. Streit
- Department of Microbiology and Biotechnology, University Hamburg, Hamburg, Germany
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Razew A, Laguri C, Vallet A, Bougault C, Kaus-Drobek M, Sabala I, Simorre JP. Staphylococcus aureus sacculus mediates activities of M23 hydrolases. Nat Commun 2023; 14:6706. [PMID: 37872144 PMCID: PMC10593780 DOI: 10.1038/s41467-023-42506-w] [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: 04/13/2023] [Accepted: 10/12/2023] [Indexed: 10/25/2023] Open
Abstract
Peptidoglycan, a gigadalton polymer, functions as the scaffold for bacterial cell walls and provides cell integrity. Peptidoglycan is remodelled by a large and diverse group of peptidoglycan hydrolases, which control bacterial cell growth and division. Over the years, many studies have focused on these enzymes, but knowledge on their action within peptidoglycan mesh from a molecular basis is scarce. Here, we provide structural insights into the interaction between short peptidoglycan fragments and the entire sacculus with two evolutionarily related peptidases of the M23 family, lysostaphin and LytM. Through nuclear magnetic resonance, mass spectrometry, information-driven modelling, site-directed mutagenesis and biochemical approaches, we propose a model in which peptidoglycan cross-linking affects the activity, selectivity and specificity of these two structurally related enzymes differently.
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Affiliation(s)
- Alicja Razew
- Universite Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 avenue des Martyrs-CS10090, Grenoble cedex 9, 38044, France
- International Institute of Molecular and Cell Biology in Warsaw, 4 Ks. Trojdena Street, 02-109, Warsaw, Poland
- Laboratory of Protein Engineering, Mossakowski Medical Research Institute, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106, Warsaw, Poland
| | - Cedric Laguri
- Universite Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 avenue des Martyrs-CS10090, Grenoble cedex 9, 38044, France
| | - Alicia Vallet
- Universite Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 avenue des Martyrs-CS10090, Grenoble cedex 9, 38044, France
| | - Catherine Bougault
- Universite Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 avenue des Martyrs-CS10090, Grenoble cedex 9, 38044, France
| | - Magdalena Kaus-Drobek
- Laboratory of Protein Engineering, Mossakowski Medical Research Institute, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106, Warsaw, Poland
| | - Izabela Sabala
- International Institute of Molecular and Cell Biology in Warsaw, 4 Ks. Trojdena Street, 02-109, Warsaw, Poland.
- Laboratory of Protein Engineering, Mossakowski Medical Research Institute, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106, Warsaw, Poland.
| | - Jean-Pierre Simorre
- Universite Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 avenue des Martyrs-CS10090, Grenoble cedex 9, 38044, France.
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5
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Zhuang A, Wu K, Lu Y, Yu J. Stable Superhydrophobic and Antimicrobial ZnO/Polytetrafluoroethylene Films via Radio Frequency (RF) Magnetron Sputtering. MICROMACHINES 2023; 14:1292. [PMID: 37512603 PMCID: PMC10383157 DOI: 10.3390/mi14071292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/11/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023]
Abstract
In this study, superhydrophobic ZnO/Polytetrafluoroethylene (ZnO/PTFE) films with water droplet contact angles (CA) observed as high as 165° and water droplet sliding angles of (SA) <1° have been prepared on glass substrates by RF magnetron sputtering. The PTFE was wrapped on a nano-rod made of a ZnO film with superhydrophobic properties while providing excellent UV resistance compared to hexadecyltrimethoxysilane (HDTMS) hydrophobic agents. The upper surface of the rough ZnO film was coated with PTFE, and most of the underlying coating was bare ZnO, which could well make contact with bacteria. For the Gram-negative strain, E. coli, the cell viability count of the ZnO/PTFE sample (3.5 log reduction, 99.96%) was conspicuously lower than that of the ZnO/HDTMS sample (1.2 log reduction, 93.87%) under 1 h illumination of UV light, which showed that the ZnO/PTFE sample has a better photocatalytic property than the ZnO/ HDTMS films. The ZnO/PTFE films also showed good mechanical robustness, which is an important consideration in their widespread real-world adoption.
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Affiliation(s)
- Aoyun Zhuang
- Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province, College of Mechanical Engineering, Quzhou University, Quzhou 324000, China
| | - Ke Wu
- Department of Chemistry, University College London, 20 Gordon Street, London WC1E 0AJ, UK
| | - Yao Lu
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Jianping Yu
- Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province, College of Mechanical Engineering, Quzhou University, Quzhou 324000, China
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6
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Leidecker M, Bertling A, Hussain M, Bischoff M, Eble JA, Fender AC, Jurk K, Rumpf C, Herrmann M, Kehrel BE, Niemann S. Protein Disulfide Isomerase and Extracellular Adherence Protein Cooperatively Potentiate Staphylococcal Invasion into Endothelial Cells. Microbiol Spectr 2023; 11:e0388622. [PMID: 36995240 PMCID: PMC10269700 DOI: 10.1128/spectrum.03886-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 03/09/2023] [Indexed: 03/31/2023] Open
Abstract
Invasion of host cells is an important feature of Staphylococcus aureus. The main internalization pathway involves binding of the bacteria to host cells, e.g., endothelial cells, via a fibronectin (Fn) bridge between S. aureus Fn binding proteins and α5β1-integrin, followed by phagocytosis. The secreted extracellular adherence protein (Eap) has been shown to promote this cellular uptake pathway of not only S. aureus, but also of bacteria otherwise poorly taken up by host cells, such as Staphylococcus carnosus. The exact mechanisms are still unknown. Previously, we demonstrated that Eap induces platelet activation by stimulation of the protein disulfide isomerase (PDI), a catalyst of thiol-disulfide exchange reactions. Here, we show that Eap promotes PDI activity on the surface of endothelial cells, and that this contributes critically to Eap-driven staphylococcal invasion. PDI-stimulated β1-integrin activation followed by increased Fn binding to host cells likely accounts for the Eap-enhanced uptake of S. aureus into non-professional phagocytes. Additionally, Eap supports the binding of S. carnosus to Fn-α5β1 integrin, thereby allowing its uptake into endothelial cells. To our knowledge, this is the first demonstration that PDI is crucial for the uptake of bacteria into host cells. We describe a hitherto unknown function of Eap-the promotion of an enzymatic activity with subsequent enhancement of bacterial uptake-and thus broaden mechanistic insights into its importance as a driver of bacterial pathogenicity. IMPORTANCE Staphylococcus aureus can invade and persist in non-professional phagocytes, thereby escaping host defense mechanisms and antibiotic treatment. The intracellular lifestyle of S. aureus contributes to the development of infection, e.g., in infective endocarditis or chronic osteomyelitis. The extracellular adherence protein secreted by S. aureus promotes its own internalization as well as that of bacteria that are otherwise poorly taken up by host cells, such as Staphylococcus carnosus. In our study, we demonstrate that staphylococcal uptake by endothelial cells requires catalytic disulfide exchange activity by the cell-surface protein disulfide isomerase, and that this critical enzymatic function is enhanced by Eap. The therapeutic application of PDI inhibitors has previously been investigated in the context of thrombosis and hypercoagulability. Our results add another intriguing possibility: therapeutically targeting PDI, i.e., as a candidate approach to modulate the initiation and/or course of S. aureus infectious diseases.
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Affiliation(s)
- Marleen Leidecker
- Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Anne Bertling
- Department of Anaesthesiology and Intensive Care, Experimental and Clinical Haemostasis, University Hospital of Münster, Münster, Germany
| | - Muzaffar Hussain
- Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Markus Bischoff
- Institute of Medical Microbiology and Hygiene, Saarland University, Homburg, Germany
| | - Johannes A. Eble
- Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Münster, Germany
| | - Anke C. Fender
- Department of Anaesthesiology and Intensive Care, Experimental and Clinical Haemostasis, University Hospital of Münster, Münster, Germany
- Institute of Pharmacology, University Hospital Essen, Essen, Germany
| | - Kerstin Jurk
- Department of Anaesthesiology and Intensive Care, Experimental and Clinical Haemostasis, University Hospital of Münster, Münster, Germany
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Christine Rumpf
- Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Mathias Herrmann
- Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Beate E. Kehrel
- Department of Anaesthesiology and Intensive Care, Experimental and Clinical Haemostasis, University Hospital of Münster, Münster, Germany
| | - Silke Niemann
- Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
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7
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da Silva RA, Wong JJ, Antypas H, Choo PY, Goh K, Jolly S, Liang C, Tay Kwan Sing L, Veleba M, Hu G, Chen J, Kline KA. Mitoxantrone targets both host and bacteria to overcome vancomycin resistance in Enterococcus faecalis. SCIENCE ADVANCES 2023; 9:eadd9280. [PMID: 36812322 PMCID: PMC9946351 DOI: 10.1126/sciadv.add9280] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Antibiotic resistance critically limits treatment options for infection caused by opportunistic pathogens such as enterococci. Here, we investigate the antibiotic and immunological activity of the anticancer agent mitoxantrone (MTX) in vitro and in vivo against vancomycin-resistant Enterococcus faecalis (VRE). We show that, in vitro, MTX is a potent antibiotic against Gram-positive bacteria through induction of reactive oxygen species and DNA damage. MTX also synergizes with vancomycin against VRE, rendering the resistant strains more permeable to MTX. In a murine wound infection model, single-dose MTX treatment effectively reduces VRE numbers, with further reduction when combined with vancomycin. Multiple MTX treatments accelerate wound closure. MTX also promotes macrophage recruitment and proinflammatory cytokine induction at the wound site and augments intracellular bacterial killing in macrophages by up-regulating the expression of lysosomal enzymes. These results show that MTX represents a promising bacterium- and host-targeted therapeutic for overcoming vancomycin resistance.
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Affiliation(s)
- Ronni A. G. da Silva
- Singapore-MIT Alliance for Research and Technology, Antimicrobial Drug Resistance Interdisciplinary Research Group, Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Jun Jie Wong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- Interdisciplinary Graduate Programme, Nanyang Technological University, Singapore, Singapore
| | - Haris Antypas
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Pei Yi Choo
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Karlyn Goh
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Shreya Jolly
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Cui Liang
- Singapore-MIT Alliance for Research and Technology, Antimicrobial Drug Resistance Interdisciplinary Research Group, Singapore, Singapore
| | - Leona Tay Kwan Sing
- Singapore-MIT Alliance for Research and Technology, Antimicrobial Drug Resistance Interdisciplinary Research Group, Singapore, Singapore
| | - Mark Veleba
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Guangan Hu
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jianzhu Chen
- Singapore-MIT Alliance for Research and Technology, Antimicrobial Drug Resistance Interdisciplinary Research Group, Singapore, Singapore
- Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kimberly A. Kline
- Singapore-MIT Alliance for Research and Technology, Antimicrobial Drug Resistance Interdisciplinary Research Group, Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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8
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Galarion LH, Clarke JE, Schofield H, O'Neill AJ. Comment on: Identification of a novel tedizolid resistance mutation in rpoB of MRSA after in vitro serial passage. J Antimicrob Chemother 2022; 78:317-318. [PMID: 36416794 DOI: 10.1093/jac/dkac397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Luiza H Galarion
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Justin E Clarke
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Harry Schofield
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Alex J O'Neill
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
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9
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Francis D, Farooque S, Meager A, Derks D, Leggott A, Warriner S, O'Neill AJ, Nelson A. Algorithm-driven activity-directed expansion of a series of antibacterial quinazolinones. Org Biomol Chem 2022; 20:9672-9678. [PMID: 36448404 DOI: 10.1039/d2ob01404a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Activity-directed synthesis (ADS) is a structure-blind, function driven approach that can drive the discovery of bioactive small molecules. In ADS, arrays of reactions are designed and executed, and the crude product mixtures are then directly screened to identify reactions that yield bioactive products. The design of subsequent reaction arrays is then informed by the hit reactions that are discovered. In this study, algorithms for reaction array design were developed in which the reactions to be executed were selected from a large set of virtual reactions; the reactions were selected on the basis of similarity to reactions known to yield bioactive products. The algorithms were harnessed to design arrays of photoredox-catalysed alkylation reactions whose crude products were then screened for inhibition of growth of S. aureus ATCC29213. It was demonstrated that the approach enabled expansion of a series of antibacterial quinazolinones. It is envisaged that such algorithms could ultimately enable fully autonomous activity-directed molecular discovery.
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Affiliation(s)
- Daniel Francis
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Sannia Farooque
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Archie Meager
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Didi Derks
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK.
| | - Abbie Leggott
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Stuart Warriner
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Alex J O'Neill
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.,School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Adam Nelson
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
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10
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Mohamad M, Nicholson D, Saha C, Hauryliuk V, Edwards T, Atkinson G, Ranson N, O’Neill A. Sal-type ABC-F proteins: intrinsic and common mediators of pleuromutilin resistance by target protection in staphylococci. Nucleic Acids Res 2022; 50:2128-2142. [PMID: 35137182 PMCID: PMC8887462 DOI: 10.1093/nar/gkac058] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 01/14/2022] [Accepted: 01/26/2022] [Indexed: 11/14/2022] Open
Abstract
The first member of the pleuromutilin (PLM) class suitable for systemic antibacterial chemotherapy in humans recently entered clinical use, underscoring the need to better understand mechanisms of PLM resistance in disease-causing bacterial genera. Of the proteins reported to mediate PLM resistance in staphylococci, the least-well studied to date is Sal(A), a putative ABC-F NTPase that-by analogy to other proteins of this type-may act to protect the ribosome from PLMs. Here, we establish the importance of Sal proteins as a common source of PLM resistance across multiple species of staphylococci. Sal(A) is revealed as but one member of a larger group of Sal-type ABC-F proteins that vary considerably in their ability to mediate resistance to PLMs and other antibiotics. We find that specific sal genes are intrinsic to particular staphylococcal species, and show that this gene family is likely ancestral to the genus Staphylococcus. Finally, we solve the cryo-EM structure of a representative Sal-type protein (Sal(B)) in complex with the staphylococcal 70S ribosome, revealing that Sal-type proteins bind into the E site to mediate target protection, likely by displacing PLMs and other antibiotics via an allosteric mechanism.
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Affiliation(s)
- Merianne Mohamad
- Astbury Centre for Structural Molecular Biology and School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - David Nicholson
- Astbury Centre for Structural Molecular Biology and School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Chayan Kumar Saha
- Department of Molecular Biology, Umeå University, 90187 Umeå, Sweden
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
| | - Vasili Hauryliuk
- Department of Molecular Biology, Umeå University, 90187 Umeå, Sweden
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
| | - Thomas A Edwards
- Astbury Centre for Structural Molecular Biology and School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Gemma C Atkinson
- Department of Molecular Biology, Umeå University, 90187 Umeå, Sweden
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
| | - Neil A Ranson
- Astbury Centre for Structural Molecular Biology and School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Alex J O’Neill
- Astbury Centre for Structural Molecular Biology and School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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11
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Abdul Hamid AI, Cara A, Diot A, Laurent F, Josse J, Gueirard P. Differential Early in vivo Dynamics and Functionality of Recruited Polymorphonuclear Neutrophils After Infection by Planktonic or Biofilm Staphylococcus aureus. Front Microbiol 2021; 12:728429. [PMID: 34526981 PMCID: PMC8435793 DOI: 10.3389/fmicb.2021.728429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/05/2021] [Indexed: 12/28/2022] Open
Abstract
Staphylococcus aureus is a human pathogen known for its capacity to shift between the planktonic and biofilm lifestyles. In vivo, the antimicrobial immune response is characterized by the recruitment of inflammatory phagocytes, namely polymorphonuclear neutrophils (PMNs) and monocytes/macrophages. Immune responses to planktonic bacteria have been extensively studied, but many questions remain about how biofilms can modulate inflammatory responses and cause recurrent infections in live vertebrates. Thus, the use of biologically sound experimental models is essential to study the specific immune signatures elicited by biofilms. Here, a mouse ear pinna model of infection was used to compare early innate immune responses toward S. aureus planktonic or biofilm bacteria. Flow cytometry and cytokine assays were carried out to study the inflammatory responses in infected tissues. These data were complemented with intravital confocal imaging analyses, allowing the real-time observation of the dynamic interactions between EGFP + phagocytes and bacteria in the ear pinna tissue of LysM-EGFP transgenic mice. Both bacterial forms induced an early and considerable recruitment of phagocytes in the ear tissue, associated with a predominantly pro-inflammatory cytokine profile. The inflammatory response was mostly composed of PMNs in the skin and the auricular lymph node. However, the kinetics of PMN recruitment were different between the 2 forms in the first 2 days post-infection (pi). Two hours pi, biofilm inocula recruited more PMNs than planktonic bacteria, but with decreased motility parameters and capacity to emit pseudopods. Inversely, biofilm inocula recruited less PMNs 2 days pi, but with an “over-activated” status, illustrated by an increased phagocytic activity, CD11b level of expression and ROS production. Thus, the mouse ear pinna model allowed us to reveal specific differences in the dynamics of recruitment and functional properties of phagocytes against biofilms. These differences would influence the specific adaptive immune responses to biofilms elicited in the lymphoid tissues.
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Affiliation(s)
- Aizat Iman Abdul Hamid
- Laboratoire Microorganismes: Génome et Environnement, CNRS UMR 6023, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Andréa Cara
- Centre International de Recherche et Infectiologie, Inserm U1111, CNRS UMR 5308, École Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Alan Diot
- Centre International de Recherche et Infectiologie, Inserm U1111, CNRS UMR 5308, École Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Frédéric Laurent
- Centre International de Recherche et Infectiologie, Inserm U1111, CNRS UMR 5308, École Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Jérôme Josse
- Centre International de Recherche et Infectiologie, Inserm U1111, CNRS UMR 5308, École Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Pascale Gueirard
- Laboratoire Microorganismes: Génome et Environnement, CNRS UMR 6023, Université Clermont Auvergne, Clermont-Ferrand, France
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12
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Pertusati F, Pileggi E, Richards J, Wootton M, Van Leemputte T, Persoons L, De Coster D, Villanueva X, Daelemans D, Steenackers H, McGuigan C, Serpi M. Drug repurposing: phosphate prodrugs of anticancer and antiviral FDA-approved nucleosides as novel antimicrobials. J Antimicrob Chemother 2021; 75:2864-2878. [PMID: 32688391 DOI: 10.1093/jac/dkaa268] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 05/09/2020] [Accepted: 05/15/2020] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVES Following a drug repurposing approach, we aimed to investigate and compare the antibacterial and antibiofilm activities of different classes of phosphate prodrugs (HepDirect, cycloSal, SATE and mix SATE) of antiviral and anticancer FDA-approved nucleoside drugs [zidovudine (AZT), floxouridine (FUDR) and gemcitabine (GEM)] against a variety of pathogenic Gram-positive and -negative bacteria. METHODS Ten prodrugs were synthesized and screened for antibacterial activity against seven Gram-negative and two Gram-positive isolates fully susceptible to traditional antibiotics, alongside six Gram-negative and five Gram-positive isolates with resistance mechanisms. Their ability to prevent and eradicate biofilms of different bacterial pathogens in relation to planktonic growth inhibition was also evaluated, together with their effect on proliferation, viability and apoptosis of different eukaryotic cells. RESULTS The prodrugs showed decreased antibacterial activity compared with the parent nucleosides. cycloSal-GEM-monophosphate (MP) prodrugs 20a and 20b were the most active agents against Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus) and retained their activity against antibiotic-resistant isolates. cycloSal-FUDR-MP 21a partially retained good activity against the Gram-positive bacteria E. faecalis, Enterococcus faecium and S. aureus. Most of the prodrugs tested displayed very potent preventive antibiofilm specific activity, but not curative. In terms of cytotoxicity, AZT prodrugs did not affect apoptosis or cell viability at the highest concentration tested, and only weak effects on apoptosis and/or cell viability were observed for GEM and FUDR prodrugs. CONCLUSIONS Among the different prodrug approaches, the cycloSal prodrugs appeared the most effective. In particular, cycloSal (17a) and mix SATE (26) AZT prodrugs combine the lowest cytotoxicity with high and broad antibacterial and antibiofilm activity against Gram-negative bacteria.
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Affiliation(s)
- Fabrizio Pertusati
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, King Edward VII Avenue, Cardiff CF10 3NB, UK
| | - Elisa Pileggi
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, King Edward VII Avenue, Cardiff CF10 3NB, UK
| | - Jennifer Richards
- Public Health Wales Microbiology Cardiff, University Hospital of Wales, Heath Park, Cardiff CF14 4XW, UK
| | - Mandy Wootton
- Public Health Wales Microbiology Cardiff, University Hospital of Wales, Heath Park, Cardiff CF14 4XW, UK
| | - Thijs Van Leemputte
- Centre of Microbial and Plant Genetics, Kasteelpark Arenberg 20, bus 2460, B-3001 Leuven, Belgium
| | - Leentje Persoons
- Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, Herestraat 49-box 1043, Leuven 3000, Belgium
| | - David De Coster
- Centre of Microbial and Plant Genetics, Kasteelpark Arenberg 20, bus 2460, B-3001 Leuven, Belgium
| | - Xabier Villanueva
- Centre of Microbial and Plant Genetics, Kasteelpark Arenberg 20, bus 2460, B-3001 Leuven, Belgium
| | - Dirk Daelemans
- Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, Herestraat 49-box 1043, Leuven 3000, Belgium
| | - Hans Steenackers
- Centre of Microbial and Plant Genetics, Kasteelpark Arenberg 20, bus 2460, B-3001 Leuven, Belgium
| | - Christopher McGuigan
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, King Edward VII Avenue, Cardiff CF10 3NB, UK
| | - Michaela Serpi
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, King Edward VII Avenue, Cardiff CF10 3NB, UK
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13
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Crowe-McAuliffe C, Murina V, Turnbull KJ, Kasari M, Mohamad M, Polte C, Takada H, Vaitkevicius K, Johansson J, Ignatova Z, Atkinson GC, O'Neill AJ, Hauryliuk V, Wilson DN. Structural basis of ABCF-mediated resistance to pleuromutilin, lincosamide, and streptogramin A antibiotics in Gram-positive pathogens. Nat Commun 2021; 12:3577. [PMID: 34117249 PMCID: PMC8196190 DOI: 10.1038/s41467-021-23753-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 05/11/2021] [Indexed: 02/05/2023] Open
Abstract
Target protection proteins confer resistance to the host organism by directly binding to the antibiotic target. One class of such proteins are the antibiotic resistance (ARE) ATP-binding cassette (ABC) proteins of the F-subtype (ARE-ABCFs), which are widely distributed throughout Gram-positive bacteria and bind the ribosome to alleviate translational inhibition from antibiotics that target the large ribosomal subunit. Here, we present single-particle cryo-EM structures of ARE-ABCF-ribosome complexes from three Gram-positive pathogens: Enterococcus faecalis LsaA, Staphylococcus haemolyticus VgaALC and Listeria monocytogenes VgaL. Supported by extensive mutagenesis analysis, these structures enable a general model for antibiotic resistance mediated by these ARE-ABCFs to be proposed. In this model, ABCF binding to the antibiotic-stalled ribosome mediates antibiotic release via mechanistically diverse long-range conformational relays that converge on a few conserved ribosomal RNA nucleotides located at the peptidyltransferase center. These insights are important for the future development of antibiotics that overcome such target protection resistance mechanisms.
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Affiliation(s)
| | - Victoriia Murina
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Kathryn Jane Turnbull
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Marje Kasari
- University of Tartu, Institute of Technology, Tartu, Estonia
| | - Merianne Mohamad
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Christine Polte
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany
| | - Hiraku Takada
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Karolis Vaitkevicius
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Jörgen Johansson
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Zoya Ignatova
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany
| | | | - Alex J O'Neill
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Vasili Hauryliuk
- Department of Molecular Biology, Umeå University, Umeå, Sweden.
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden.
- University of Tartu, Institute of Technology, Tartu, Estonia.
- Department of Experimental Medical Science, Lund University, Lund, Sweden.
| | - Daniel N Wilson
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany.
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14
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Galarion LH, Mohamad M, Alzeyadi Z, Randall CP, O'Neill AJ. A platform for detecting cross-resistance in antibacterial drug discovery. J Antimicrob Chemother 2021; 76:1467-1471. [PMID: 33755133 PMCID: PMC8843079 DOI: 10.1093/jac/dkab063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 02/12/2021] [Indexed: 11/16/2022] Open
Abstract
Background To address the growing antibiotic resistance problem, new antibacterial drugs must exert activity against pathogens resistant to agents already in use. With a view to providing a rapid means for deselecting antibacterial drug candidates that fail to meet this requirement, we report here the generation and application of a platform for detecting cross-resistance between established and novel antibacterial agents. Methods This first iteration of the cross-resistance platform (CRP) consists of 28 strains of defined resistance genotype, established in a uniform genetic background (the SH1000 strain of the clinically significant pathogen Staphylococcus aureus). Most CRP members were engineered through introduction of constitutively expressed resistance determinants on a low copy-number plasmid, with a smaller number selected as spontaneous resistant mutants. Results Members of the CRP collectively exhibit resistance to many of the major classes of antibacterial agent in use. We employed the CRP to test two antibiotics that have been proposed in the literature as potential drug candidates: γ-actinorhodin and batumin. No cross-resistance was detected for γ-actinorhodin, whilst a CRP member resistant to triclosan exhibited a 32-fold reduction in susceptibility to batumin. Thus, a resistance phenotype that already exists in clinical strains mediates profound resistance to batumin, implying that this compound is not a promising antibacterial drug candidate. Conclusions By detecting cross-resistance between established and novel antibacterial agents, the CRP offers the ability to deselect compounds whose activity is substantially impaired by existing resistance mechanisms. The CRP therefore represents a useful addition to the antibacterial drug discovery toolbox.
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Affiliation(s)
- Luiza H Galarion
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Merianne Mohamad
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Zeyad Alzeyadi
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Christopher P Randall
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Alex J O'Neill
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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15
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Smith OJ, Wicaksana A, Davidson D, Spratt D, Mosahebi A. An evaluation of the bacteriostatic effect of platelet-rich plasma. Int Wound J 2021; 18:448-456. [PMID: 33476481 PMCID: PMC8273594 DOI: 10.1111/iwj.13545] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 12/13/2020] [Accepted: 12/18/2020] [Indexed: 12/01/2022] Open
Abstract
Chronic wounds are a considerable health burden with high morbidity and poor rates of healing. Colonisation of chronic wounds by bacteria can be a significant factor in their poor healing rate. These bacteria can develop antibiotic resistance over time and can lead to wound infections, systemic illness, and occasionally amputation. When a large number of micro-organisms colonise wounds, they can lead to biofilm formation, which are self-perpetuating colonies of bacteria closed within an extracellular matrix, which are poorly penetrated by antibiotics. Platelet-rich plasma (PRP) is an autologous blood product rich in growth factors and cytokines that are involved in an inflammatory response. PRP can be injected or applied to a wound as a topical gel, and there is some interest regarding its antimicrobial properties and whether this can improve wound healing. This study aimed to evaluate the in vitro bacteriostatic effect of PRP. PRP was collected from healthy volunteers and processed into two preparations: activated PRP-activated with calcium chloride and ethanol; inactivated PRP. The activity of each preparation against Staphylococcus aureus and Staphylococcus epidermis was evaluated against a control by three experiments: bacterial kill assay to assess planktonic bacterial growth; plate colony assay to assess bacterial colony growth; and colony biofilm assay to assess biofilm growth. Compared with control, both preparations of PRP significantly inhibited growth of planktonic S aureus and S epidermis. Activated PRP reduced planktonic bacterial concentration more than inactivated PRP in both bacteria. Both PRP preparations significantly reduced bacterial colony counts for both bacteria when compared with control; however, there was no difference between the two. There was no difference found between biofilm growth in either PRP against control or against the other preparation. This study demonstrates that PRP does have an inhibitory effect on the growth of common wound pathogens. Activation may be an important factor in increasing the antimicrobial effect of PRP. However, we did not find evidence of an effect against more complex bacterial colonies.
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Affiliation(s)
- Oliver J Smith
- Department of Plastic Surgery, Royal Free Hospital, London, UK.,Division of Surgery and Interventional Science, University College London, London, UK
| | - Aditya Wicaksana
- Division of Surgery and Interventional Science, University College London, London, UK.,Division of Plastic Surgery, Faculty of Medicine Universitas Indonesia/Dr. Cipto Mangunkusumo National Hospital, Jakarta, Indonesia
| | - Donald Davidson
- Microbial Diseases, Eastman Dental Institute, Faculty of Medical Sciences, University College London, London, UK
| | - David Spratt
- Microbial Diseases, Eastman Dental Institute, Faculty of Medical Sciences, University College London, London, UK
| | - Ash Mosahebi
- Department of Plastic Surgery, Royal Free Hospital, London, UK.,Division of Surgery and Interventional Science, University College London, London, UK
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16
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Sauvat L, Abdul Hamid AI, Blavignac C, Josse J, Lesens O, Gueirard P. Biofilm-coated microbeads and the mouse ear skin: An innovative model for analysing anti-biofilm immune response in vivo. PLoS One 2020; 15:e0243500. [PMID: 33275636 PMCID: PMC7717515 DOI: 10.1371/journal.pone.0243500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 11/20/2020] [Indexed: 12/12/2022] Open
Abstract
Owing to its ability to form biofilms, Staphylococcus aureus is responsible for an increasing number of infections on implantable medical devices. The aim of this study was to develop a mouse model using microbeads coated with S. aureus biofilm to simulate such infections and to analyse the dynamics of anti-biofilm inflammatory responses by intravital imaging. Scanning electron microscopy and flow cytometry were used in vitro to study the ability of an mCherry fluorescent strain of S. aureus to coat silica microbeads. Biofilm-coated microbeads were then inoculated intradermally into the ear tissue of LysM-EGFP transgenic mice (EGFP fluorescent immune cells). General and specific real-time inflammatory responses were studied in ear tissue by confocal microscopy at early (4-6h) and late time points (after 24h) after injection. The displacement properties of immune cells were analysed. The responses were compared with those obtained in control mice injected with only microbeads. In vitro, our protocol was capable of generating reproducible inocula of biofilm-coated microbeads verified by labelling matrix components, observing biofilm ultrastructure and confirmed in vivo and in situ with a matrix specific fluorescent probe. In vivo, a major inflammatory response was observed in the mouse ear pinna at both time points. Real-time observations of cell recruitment at injection sites showed that immune cells had difficulty in accessing biofilm bacteria and highlighted areas of direct interaction. The average speed of cells was lower in infected mice compared to control mice and in tissue areas where direct contact between immune cells and bacteria was observed, the average cell velocity and linearity were decreased in comparison to cells in areas where no bacteria were visible. This model provides an innovative way to analyse specific immune responses against biofilm infections on medical devices. It paves the way for live evaluation of the effectiveness of immunomodulatory therapies combined with antibiotics.
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Affiliation(s)
- Léo Sauvat
- Laboratoire Microorganismes: Génome et Environnement, Université Clermont Auvergne, UMR CNRS 6023, Clermont-Ferrand, France.,Infectious and Tropical Diseases Department, CRIOA, CRMVT, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Aizat Iman Abdul Hamid
- Laboratoire Microorganismes: Génome et Environnement, Université Clermont Auvergne, UMR CNRS 6023, Clermont-Ferrand, France
| | - Christelle Blavignac
- Centre Imagerie Cellulaire Santé, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Jérôme Josse
- CIRI-Centre International de Recherche en Infectiologie, Inserm, U1111, CNRS, UMR5308, École Normale Supérieure de Lyon, Université Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Olivier Lesens
- Laboratoire Microorganismes: Génome et Environnement, Université Clermont Auvergne, UMR CNRS 6023, Clermont-Ferrand, France.,Infectious and Tropical Diseases Department, CRIOA, CRMVT, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Pascale Gueirard
- Laboratoire Microorganismes: Génome et Environnement, Université Clermont Auvergne, UMR CNRS 6023, Clermont-Ferrand, France
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17
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Alhede M, Lorenz M, Fritz BG, Jensen PØ, Ring HC, Bay L, Bjarnsholt T. Bacterial aggregate size determines phagocytosis efficiency of polymorphonuclear leukocytes. Med Microbiol Immunol 2020; 209:669-680. [PMID: 32880037 PMCID: PMC7568703 DOI: 10.1007/s00430-020-00691-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 08/19/2020] [Indexed: 02/06/2023]
Abstract
The ability of bacteria to aggregate and form biofilms impairs phagocytosis by polymorphonuclear leukocytes (PMNs). The aim of this study was to examine if the size of aggregates is critical for successful phagocytosis and how bacterial biofilms evade phagocytosis. We investigated the live interaction between PMNs and Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Staphylococcus epidermidis using confocal scanning laser microscopy. Aggregate size significantly affected phagocytosis outcome and larger aggregates were less likely to be phagocytized. Aggregates of S. epidermidis were also less likely to be phagocytized than equally-sized aggregates of the other three species. We found that only aggregates of approx. 5 μm diameter or smaller were consistently phagocytosed. We demonstrate that planktonic and aggregated cells of all four species significantly reduced the viability of PMNs after 4 h of incubation. Our results indicate that larger bacterial aggregates are less likely to be phagocytosed by PMNs and we propose that, if the aggregates become too large, circulating PMNs may not be able to phagocytose them quickly enough, which may lead to chronic infection.
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Affiliation(s)
- Maria Alhede
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - Melanie Lorenz
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - Blaine Gabriel Fritz
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - Peter Østrup Jensen
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark.,Department of Clinical Microbiology, Rigshospitalet, Afsnit 9301, Juliane Maries Vej 22, DK-2100, Copenhagen Ø, Denmark.,Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, 2100, Copenhagen, Denmark
| | - Hans Christian Ring
- Department of Dermatology, Bispebjerg Hospital, Nielsine Nielsens Vej 9, København, NV, Denmark
| | - Lene Bay
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - Thomas Bjarnsholt
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark. .,Department of Clinical Microbiology, Rigshospitalet, Afsnit 9301, Juliane Maries Vej 22, DK-2100, Copenhagen Ø, Denmark.
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18
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Panchal VV, Griffiths C, Mosaei H, Bilyk B, Sutton JAF, Carnell OT, Hornby DP, Green J, Hobbs JK, Kelley WL, Zenkin N, Foster SJ. Evolving MRSA: High-level β-lactam resistance in Staphylococcus aureus is associated with RNA Polymerase alterations and fine tuning of gene expression. PLoS Pathog 2020; 16:e1008672. [PMID: 32706832 PMCID: PMC7380596 DOI: 10.1371/journal.ppat.1008672] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 06/02/2020] [Indexed: 12/21/2022] Open
Abstract
Most clinical MRSA (methicillin-resistant S. aureus) isolates exhibit low-level β-lactam resistance (oxacillin MIC 2-4 μg/ml) due to the acquisition of a novel penicillin binding protein (PBP2A), encoded by mecA. However, strains can evolve high-level resistance (oxacillin MIC ≥256 μg/ml) by an unknown mechanism. Here we have developed a robust system to explore the basis of the evolution of high-level resistance by inserting mecA into the chromosome of the methicillin-sensitive S. aureus SH1000. Low-level mecA-dependent oxacillin resistance was associated with increased expression of anaerobic respiratory and fermentative genes. High-level resistant derivatives had acquired mutations in either rpoB (RNA polymerase subunit β) or rpoC (RNA polymerase subunit β') and these mutations were shown to be responsible for the observed resistance phenotype. Analysis of rpoB and rpoC mutants revealed decreased growth rates in the absence of antibiotic, and alterations to, transcription elongation. The rpoB and rpoC mutations resulted in decreased expression to parental levels, of anaerobic respiratory and fermentative genes and specific upregulation of 11 genes including mecA. There was however no direct correlation between resistance and the amount of PBP2A. A mutational analysis of the differentially expressed genes revealed that a member of the S. aureus Type VII secretion system is required for high level resistance. Interestingly, the genomes of two of the high level resistant evolved strains also contained missense mutations in this same locus. Finally, the set of genetically matched strains revealed that high level antibiotic resistance does not incur a significant fitness cost during pathogenesis. Our analysis demonstrates the complex interplay between antibiotic resistance mechanisms and core cell physiology, providing new insight into how such important resistance properties evolve.
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Affiliation(s)
- Viralkumar V. Panchal
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, United Kingdom
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
| | - Caitlin Griffiths
- Centre for Bacterial Cell Biology, Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Hamed Mosaei
- Centre for Bacterial Cell Biology, Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Bohdan Bilyk
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, United Kingdom
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
| | - Joshua A. F. Sutton
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, United Kingdom
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
| | - Oliver T. Carnell
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, United Kingdom
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
| | - David P. Hornby
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, United Kingdom
| | - Jeffrey Green
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, United Kingdom
| | - Jamie K. Hobbs
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
- Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom
| | - William L. Kelley
- Department of Microbiology and Molecular Medicine, University Hospital and Medical School of Geneva, Geneva, Switzerland
| | - Nikolay Zenkin
- Centre for Bacterial Cell Biology, Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Simon J. Foster
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, United Kingdom
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
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19
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Lee VE, O'Neill AJ. Potential for repurposing the personal care product preservatives bronopol and bronidox as broad-spectrum antibiofilm agents for topical application. J Antimicrob Chemother 2020; 74:907-911. [PMID: 30590494 DOI: 10.1093/jac/dky520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/18/2018] [Accepted: 11/16/2018] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Bacterial biofilms represent a major impediment to healing in chronic wounds and are largely refractory to the antibacterial agents currently used in wound management. From a repurposing screen of compounds considered safe for topical application in humans, we report the identification of the personal care product preservatives bronopol and bronidox as broad-spectrum antibiofilm agents and potential candidates for reducing biofilm burden in chronic wounds. METHODS Antibiofilm activity was assessed by viable counting against single-species biofilms of Staphylococcus aureus and Pseudomonas aeruginosa in the Calgary Biofilm Device, and against mixed-species biofilms of the two organisms growing on nitrocellulose discs. RESULTS Bronopol and bronidox exhibited broad-spectrum antibiofilm activity that encompassed the two major wound pathogens, S. aureus and P. aeruginosa. When impregnated into gauze dressings at their existing maximum authorized concentrations for safe use and placed onto an established mixed-species biofilm, bronopol and bronidox completely eradicated P. aeruginosa and achieved an ∼5 log10 reduction in the S. aureus population. The antibiofilm action of bronopol and bronidox was attributed to their ability to kill slow- or non-growing bacteria found in biofilms, and both compounds exhibited synergistic antibiofilm effects in combination with established wound-treatment agents. CONCLUSIONS Bronopol and bronidox kill bacteria regardless of growth state, a property that endows them with broad-spectrum antibiofilm activity. As this effect is observed at concentrations authorized for use on human skin, these compounds represent promising candidates for the treatment of chronic wounds.
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Affiliation(s)
- Victoria E Lee
- Antimicrobial Research Centre and School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Alex J O'Neill
- Antimicrobial Research Centre and School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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20
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Häffner N, Bär J, Dengler Haunreiter V, Mairpady Shambat S, Seidl K, Crosby HA, Horswill AR, Zinkernagel AS. Intracellular Environment and agr System Affect Colony Size Heterogeneity of Staphylococcus aureus. Front Microbiol 2020; 11:1415. [PMID: 32695082 PMCID: PMC7339952 DOI: 10.3389/fmicb.2020.01415] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 06/02/2020] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus aureus causes chronic and relapsing infections, which may be difficult to treat. So-called small colony variants (SCVs) have been associated with chronic infections and their occurrence has been shown to increase under antibiotic pressure, low pH and intracellular localization. In clinics, S. aureus isolated from invasive infections often show a dysfunction in the accessory gene regulator (agr), a major virulence regulatory system in S. aureus. To assess whether intracellular environment and agr function influence SCV formation, an infection model was established using lung epithelial cells and skin fibroblasts. This allowed analyzing intracellular survival and localization of a panel of S. aureus wild type strains and their isogenic agr knock out mutants as well as a natural dysfunctional agr strain by confocal laser scanning microscopy (CLSM). Furthermore, bacterial colonies were quantified after 1, 3, and 5 days of intracellular survival by time-lapse analysis to determine kinetics of colony appearance and SCV formation. Here, we show that S. aureus strains with an agr knock out predominantly resided in a neutral environment, whereas wild type strains and an agr complemented strain resided in an acidic environment. S. aureus agr mutants derived from an intracellular environment showed a higher percentage of SCVs as compared to their corresponding wild type strains. Neutralizing acidic phagolysosomes with chloroquine resulted in a significant reduction of SCVs in S. aureus wild type strain 6850, but not in its agr mutant indicating a pH dependent formation of SCVs in the wild type strain. The in-depth understanding of the interplay between intracellular persistence, agr function and pH should help to identify new therapeutic options facilitating the treatment of chronic S. aureus infections in the future.
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Affiliation(s)
- Nicola Häffner
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Julian Bär
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Vanina Dengler Haunreiter
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Srikanth Mairpady Shambat
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Kati Seidl
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Heidi A Crosby
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States.,Department of Veterans Affairs Eastern Colorado Health Care System, Denver, CO, United States
| | - Annelies S Zinkernagel
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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21
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Svenningsen SW, Frederiksen RF, Counil C, Ficker M, Leisner JJ, Christensen JB. Synthesis and Antimicrobial Properties of a Ciprofloxacin and PAMAM-dendrimer Conjugate. Molecules 2020; 25:molecules25061389. [PMID: 32197523 PMCID: PMC7146445 DOI: 10.3390/molecules25061389] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/13/2020] [Accepted: 03/17/2020] [Indexed: 02/01/2023] Open
Abstract
Infections caused by bacteria resistant to antibiotics are an increasing problem. Multivalent antibiotics could be a solution. In the present study, a covalent conjugate between Ciprofloxacin and a G0-PAMAM dendrimer has been synthesized and tested against clinically relevant Gram-positive and Gram-negative bacteria. The conjugate has antimicrobial activity and there is a positive dendritic effect compared to Ciprofloxacin itself.
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Affiliation(s)
- Søren Wedel Svenningsen
- Department of Chemistry, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark; (S.W.S.); (C.C.); (M.F.)
| | - Rikki Franklin Frederiksen
- Department of Veterinary and Animal Sciences, Food Safety and Zoonoses, University of Copenhagen, Grønnegårdsvej 15, DK-1870 Frederiksberg C, Denmark; (R.F.F.); (J.J.L.)
| | - Claire Counil
- Department of Chemistry, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark; (S.W.S.); (C.C.); (M.F.)
| | - Mario Ficker
- Department of Chemistry, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark; (S.W.S.); (C.C.); (M.F.)
| | - Jørgen J. Leisner
- Department of Veterinary and Animal Sciences, Food Safety and Zoonoses, University of Copenhagen, Grønnegårdsvej 15, DK-1870 Frederiksberg C, Denmark; (R.F.F.); (J.J.L.)
| | - Jørn Bolstad Christensen
- Department of Chemistry, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark; (S.W.S.); (C.C.); (M.F.)
- Correspondence: ; Tel.: +45-3533-2452
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22
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Smitten KL, Fairbanks SD, Robertson CC, Bernardino de la Serna J, Foster SJ, Thomas JA. Ruthenium based antimicrobial theranostics - using nanoscopy to identify therapeutic targets and resistance mechanisms in Staphylococcus aureus. Chem Sci 2020; 11:70-79. [PMID: 32110358 PMCID: PMC7012045 DOI: 10.1039/c9sc04710g] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 10/28/2019] [Indexed: 12/13/2022] Open
Abstract
In previous studies we reported that specific dinuclear RuII complexes are particularly active against pathogenic Gram-negative bacteria and, unusually for this class of compounds, appeared to display lowered activity against Gram-positive bacteria. With the aim of identifying resistance mechanisms specific to Gram-positive bacteria, the uptake and antimicrobial activity of the lead complex against Staphylococcus aureus SH1000 and other isolates, including MRSA was investigated. This revealed differential, strain specific, sensitivity to the complex. Exploiting the inherent luminescent properties of the RuII complex, super-resolution STED nanoscopy was used to image its initial interaction with S. aureus and confirm its cellular internalization. Membrane damage assays and transmission electron microscopy confirm that the complex disrupts the bacterial membrane structure before internalization, which ultimately results in a small amount of DNA damage. A known resistance mechanism against cationic antimicrobials in Gram-positive bacteria involves increased expression of the mprF gene as this results in an accumulation of positively charged lysyl-phosphatidylglycerol on the outer leaflet of the cytoplasmic membrane that electrostatically repel cationic species. Consistent with this model, it was found that an mprF deficient strain was particularly susceptible to treatment with the lead complex. More detailed co-staining studies also revealed that the complex was more active in S. aureus strains missing, or with altered, wall teichoic acids.
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Affiliation(s)
- Kirsty L Smitten
- Department of Chemistry , University of Sheffield , Sheffield S10 2TN , UK . ;
- The Florey Institute and Department of Molecular Biology and Biotechnology , University of Sheffield , S10 2TN , UK
| | - Simon D Fairbanks
- Department of Chemistry , University of Sheffield , Sheffield S10 2TN , UK . ;
| | - Craig C Robertson
- Department of Chemistry , University of Sheffield , Sheffield S10 2TN , UK . ;
| | - Jorge Bernardino de la Serna
- National Heart and Lung Institute , Faculty of Medicine , Imperial College London , South Kensington Campus , London SW7 2AZ , UK
- Research Complex at Harwell , Rutherford Appleton Laboratory , Central Laser Facility , United Kingdom Research and Innovation , OX11 0FA , UK
| | - Simon J Foster
- The Florey Institute and Department of Molecular Biology and Biotechnology , University of Sheffield , S10 2TN , UK
| | - Jim A Thomas
- Department of Chemistry , University of Sheffield , Sheffield S10 2TN , UK . ;
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23
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Millette G, Langlois JP, Brouillette E, Frost EH, Cantin AM, Malouin F. Despite Antagonism in vitro, Pseudomonas aeruginosa Enhances Staphylococcus aureus Colonization in a Murine Lung Infection Model. Front Microbiol 2019; 10:2880. [PMID: 31921058 PMCID: PMC6923662 DOI: 10.3389/fmicb.2019.02880] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 11/29/2019] [Indexed: 11/13/2022] Open
Abstract
Staphylococcus aureus and Pseudomonas aeruginosa are prevalent lung pathogens in cystic fibrosis (CF). Whereas co-infection worsens the clinical outcome, prototypical strains are usually antagonistic in vitro. We sought to resolve the discrepancy between these in vitro and in vivo observations. In vitro, growth kinetics for co-cultures of co-isolates from CF patients showed that not all P. aeruginosa strains affected S. aureus viability. On solid media, S. aureus slow-growing colonies were visualized around some P. aeruginosa strains whether or not S. aureus viability was reduced in liquid co-cultures. The S. aureus-P. aeruginosa interactions were then characterized in a mouse lung infection model. Lung homogenates were plated on selective media allowing colony counts of either bacterium. Overall, 35 P. aeruginosa and 10 S. aureus strains (clinical, reference, and mutant strains), for a total of 200 co-infections, were evaluated. We observed that S. aureus colonization of lung tissues was promoted by P. aeruginosa and even by strains showing antagonism in vitro. Promotion was proportional to the extent of P. aeruginosa colonization, but no correlation was found with the degree of myeloperoxidase quantification (as marker of inflammation) or with specific virulence-associated factors using known mutant strains of S. aureus and P. aeruginosa. On the other hand, P. aeruginosa significantly increased the expression of two possible cell receptors for S. aureus, i.e., ICAM-1 and ITGA-5 (marker for integrin α5β1) in lung tissue, while mono-infections by S. aureus did not. This study provides insights on polymicrobial interactions that may influence the progression of CF-associated pulmonary infections.
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Affiliation(s)
- Guillaume Millette
- Centre d'Étude et de Valorisation de la Diversité Microbienne, Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Jean-Philippe Langlois
- Centre d'Étude et de Valorisation de la Diversité Microbienne, Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Eric Brouillette
- Centre d'Étude et de Valorisation de la Diversité Microbienne, Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Eric H Frost
- Département de Microbiologie et d'Infectiologie, Faculté de Médecine et de Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - André M Cantin
- Service de Pneumologie, Département de Médecine, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - François Malouin
- Centre d'Étude et de Valorisation de la Diversité Microbienne, Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
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24
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Ji Y, Bolhuis A, Watson ML. Staphylococcus aureus products subvert the Burkholderia cenocepacia-induced inflammatory response in airway epithelial cells. J Med Microbiol 2019; 68:1813-1822. [PMID: 31674896 DOI: 10.1099/jmm.0.001100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Introduction. Chronic pulmonary infection is associated with colonization with multiple micro-organisms but host-microbe and microbe-microbe interactions are poorly understood.Aim. This study aims to investigate the differences in host responses to mono- and co-infection with S. aureus and B. cenocepacia in human airway epithelial cells.Methodology. We assessed the effect of co-infection with B. cenocepacia and S. aureus on host signalling and inflammatory responses in the human airway epithelial cell line 16HBE, using ELISA and western blot analysis.Results. The results show that B. cenocepacia activates MAPK and NF-κB signalling pathways, subsequently eliciting robust interleukin (IL)-8 production. However, when airway epithelial cells were co-treated with live B. cenocepacia bacteria and S. aureus supernatants (conditioned medium), the pro-inflammatory response was attenuated. This anti-inflammatory effect was widely exhibited in the S. aureus isolates tested and was mediated via reduced MAPK and NF-κB signalling, but not via IL-1 receptor or tumour necrosis factor receptor modulation. The staphylococcal effectors were characterized as small, heat-stable, non-proteinaceous and not cell wall-related factors.Conclusion. This study demonstrates for the first time the host response in a S. aureus/B. cenocepacia co-infection model and provides insight into a staphylococcal immune evasion mechanism, as well as a therapeutic intervention for excessive inflammation.
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Affiliation(s)
- Yuan Ji
- Department of Pharmacy and Pharmacology, University of Bath, BA2 7AY, UK
| | - Albert Bolhuis
- Department of Pharmacy and Pharmacology, University of Bath, BA2 7AY, UK
| | - Malcolm L Watson
- Department of Pharmacy and Pharmacology, University of Bath, BA2 7AY, UK
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25
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Transient Silencing of Antibiotic Resistance by Mutation Represents a Significant Potential Source of Unanticipated Therapeutic Failure. mBio 2019; 10:mBio.01755-19. [PMID: 31662453 PMCID: PMC6819657 DOI: 10.1128/mbio.01755-19] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Sporadic literature reports describe isolates of pathogenic bacteria that harbor an antibiotic resistance determinant but remain susceptible to the corresponding antibiotic as a consequence of a genetic defect. Such strains represent a source from which antibiotic resistance may reemerge to cause treatment failure in patients. Here, we report a systematic investigation into the prevalence and nature of this phenomenon, which we term silencing of antibiotic resistance by mutation (SARM). Instances of SARM were detected among 1,470 Staphylococcus aureus isolates through side-by-side comparison of antibiotic resistance genotype (as determined by whole-genome sequencing) versus phenotype (as assessed through susceptibility testing). Of the isolates analyzed, 152 (10.3%) harbored a silenced resistance gene, including 46 (3.1%) that exhibited SARM to currently deployed antistaphylococcal drugs. SARM resulted from diverse mutational events but most commonly through frameshift mutation of resistance determinants as a result of point deletion in poly(A) tracts. The majority (∼90%) of SARM strains reverted to antibiotic resistance at frequencies of ≥10-9; thus, while appearing antibiotic sensitive in the clinical microbiology laboratory, most S. aureus isolates exhibiting SARM will revert to antibiotic resistance at frequencies achievable in patients. In view of its prevalence in a major pathogen, SARM represents a significant potential threat to the therapeutic efficacy of antibiotics.IMPORTANCE Antibiotic resistance hinders the treatment of bacterial infection. To guide effective therapy, clinical microbiology laboratories routinely perform susceptibility testing to determine the antibiotic sensitivity of an infecting pathogen. This approach relies on the assumption that it can reliably distinguish bacteria capable of expressing antibiotic resistance in patients, an idea challenged by the present study. We report that the important human pathogen Staphylococcus aureus frequently carries antibiotic resistance genes that have become inactivated ("silenced") by mutation, leading strains to appear antibiotic sensitive. However, resistance can rapidly reemerge in most such cases, at frequencies readily achievable in infected patients. Silent antibiotic resistance is therefore prevalent, transient, and evades routine detection, rendering it a significant potential threat to antibacterial chemotherapy.
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26
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Van Oijen GW, Croughs PD, Hagenaars T, Verhofstad MHJ, Van Lieshout EMM. Antimicrobial Effect Of Visible Blue Light Used In A Minimally Invasive Intramedullary Fracture Stabilization System. J Bone Jt Infect 2019; 4:216-222. [PMID: 31700769 PMCID: PMC6831804 DOI: 10.7150/jbji.35629] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 08/06/2019] [Indexed: 01/02/2023] Open
Abstract
Introduction: Since 2009, the IlluminOss® System is being used as an intramedullary fracture treatment. The system is characterized by the use of blue light to polymerize liquid monomer after its infusion in a polyethylene terephthalate balloon. Very few infections of the material have been observed, which might be explained by the possible antimicrobial side-effect of the blue light used in this intramedullary fracture stabilization system. This study aimed to assess this antimicrobial (side-)effect on S. aureus. Methods: A suspension of 1.5 x 103 CFU/ml of 8325-4 S. aureus was placed into five, custom made, black delrin cylinders. The implant was placed into the cylinders and the light source was activated for 200, 400, 600, 800, or 1,000 seconds. 100 µL of the light exposed suspension was grafted on blood agar and placed in a 35 degrees Celsius incubator for 24 hours. Colonies on each agar plate were counted and compared to the control plates (no blue light exposure). Results: The control plates showed a mean of 85 ± 15 colonies per plate. A statistically significant decrease was observed after 600 seconds of exposure time; mean colony count of 63 ± 4 (p <0.05). The absolute reduction was 24 ± 14 after 600 seconds exposure time. At 800 and 1,000 seconds, no statistically significant reduction was found compared with the control plates (means 72 ± 10 and 83 ± 14 colonies, respectively). Conclusions: In this study only a temporary reduction of S. aureus was observed. If future research regarding the antimicrobial characteristics of blue light used in the IlluminOss® System is desired, it should focus on the need for oxygen and its availability and the dose and manner of applying the light.
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Affiliation(s)
- Guido W Van Oijen
- Trauma Research Unit Department of Surgery, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Peter D Croughs
- Department of Microbiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Tjebbe Hagenaars
- Trauma Research Unit Department of Surgery, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Michael H J Verhofstad
- Trauma Research Unit Department of Surgery, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Esther M M Van Lieshout
- Trauma Research Unit Department of Surgery, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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27
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Cigarette smoke exposure redirects Staphylococcus aureus to a virulence profile associated with persistent infection. Sci Rep 2019; 9:10798. [PMID: 31346202 PMCID: PMC6658544 DOI: 10.1038/s41598-019-47258-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 07/07/2019] [Indexed: 01/09/2023] Open
Abstract
Tobacco smoking represents the leading preventable cause of death worldwide. Smoking is a recognised risk factor for several pathologies and is detrimental to host immune surveillance and defence. However, the impact of smoking on microbial residents of the nasopharyngeal cavity, in contact with cigarette smoke (CS), is lacking. Staphylococcus aureus is a major human pathogen that colonises the human nasopharynx and causes a wide range of infections. We investigated the impact of CS on specific virulence phenotypes important in S aureus pathogenesis. We observed strain-dependent differences following exposure to CS, namely growth inhibition, augmented biofilm formation, increased invasion of, and persistence within, bronchial alveolar epithelial cells. Additionally, we confirm the critical role of a functional accessory gene regulator (Agr) system in mediating increased biofilm development and host cell invasion and persistence following CS exposure. Furthermore, CS exposure resulted in reduced toxin production. Importantly, exposure of S aureus to CS accelerated the frequency of mutations and resulted in a significant increase in gentamicin-resistant small colony variant (SCV) formation. Mutational analysis revealed that CS induced SCVs emerge via the SOS response DNA mutagenic repair system. Taken together, our results suggest that CS redirects certain S aureus strains to a virulence profile associated with persistence.
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28
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Murina V, Kasari M, Hauryliuk V, Atkinson GC. Antibiotic resistance ABCF proteins reset the peptidyl transferase centre of the ribosome to counter translational arrest. Nucleic Acids Res 2019; 46:3753-3763. [PMID: 29415157 PMCID: PMC5909423 DOI: 10.1093/nar/gky050] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 01/22/2018] [Indexed: 12/16/2022] Open
Abstract
Several ATPases in the ATP-binding cassette F (ABCF) family confer resistance to macrolides, lincosamides and streptogramins (MLS) antibiotics. MLS are structurally distinct classes, but inhibit a common target: the peptidyl transferase (PTC) active site of the ribosome. Antibiotic resistance (ARE) ABCFs have recently been shown to operate through direct ribosomal protection, but the mechanistic details of this resistance mechanism are lacking. Using a reconstituted translational system, we dissect the molecular mechanism of Staphylococcus haemolyticus VgaALC and Enterococcus faecalis LsaA on the ribosome. We demonstrate that VgaALC is an NTPase that operates as a molecular machine strictly requiring NTP hydrolysis (not just NTP binding) for antibiotic protection. Moreover, when bound to the ribosome in the NTP-bound form, hydrolytically inactive EQ2 ABCF ARE mutants inhibit peptidyl transferase activity, suggesting a direct interaction between the ABCF ARE and the PTC. The likely structural candidate responsible for antibiotic displacement by wild type ABCF AREs, and PTC inhibition by the EQ2 mutant, is the extended inter-ABC domain linker region. Deletion of the linker region renders wild type VgaALC inactive in antibiotic protection and the EQ2 mutant inactive in PTC inhibition.
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Affiliation(s)
- Victoriia Murina
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 901 87 Umeå, Sweden
| | - Marje Kasari
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
| | - Vasili Hauryliuk
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 901 87 Umeå, Sweden.,University of Tartu, Institute of Technology, 50411 Tartu, Estonia
| | - Gemma C Atkinson
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
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29
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Peeters E, Hooyberghs G, Robijns S, De Weerdt A, Kucharíková S, Tournu H, Braem A, Čeh K, Majdič G, Španič T, Pogorevc E, Claes B, Dovgan B, Girandon L, Impellizzeri F, Erdtmann M, Krona A, Vleugels J, Fröhlich M, Garcia-Forgas J, De Brucker K, Cammue BPA, Thevissen K, Van Dijck P, Vanderleyden J, Van der Eycken E, Steenackers HP. An antibiofilm coating of 5-aryl-2-aminoimidazole covalently attached to a titanium surface. J Biomed Mater Res B Appl Biomater 2018; 107:1908-1919. [PMID: 30549192 DOI: 10.1002/jbm.b.34283] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 09/21/2018] [Accepted: 09/30/2018] [Indexed: 12/25/2022]
Abstract
Biofilms, especially those formed by Staphylococcus aureus, play a key role in the development of orthopedic implant infections. Eradication of these infections is challenging due to the elevated tolerance of biofilm cells against antimicrobial agents. In this study, we developed an antibiofilm coating consisting of 5-(4-bromophenyl)-N-cyclopentyl-1-octyl-1H-imidazol-2-amine, designated as LC0024, covalently bound to a titanium implant surface (LC0024-Ti). We showed in vitro that the LC0024-Ti surface reduces biofilm formation of S. aureus in a specific manner without reducing the planktonic cells above the biofilm, as evaluated by plate counting and fluorescence microscopy. The advantage of compounds that only inhibit biofilm formation without affecting the viability of the planktonic cells, is that reduced development of bacterial resistance is expected. To determine the antibiofilm activity of LC0024-Ti surfaces in vivo, a biomaterial-associated murine infection model was used. The results indicated a significant reduction in S. aureus biofilm formation (up to 96%) on the LC0024-Ti substrates compared to pristine titanium controls. Additionally, we found that the LC0024-Ti substrates did not affect the attachment and proliferation of human cells involved in osseointegration and bone repair. In summary, our results emphasize the clinical potential of covalent coatings of LC0024 on titanium implant surfaces to reduce the risk of orthopedic implant infections. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1908-1919, 2019.
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Affiliation(s)
- Elien Peeters
- Department of Microbial and Molecular Systems, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Kasteelpark Arenberg 20 Box 2460, 3001 Leuven, Belgium
| | - Geert Hooyberghs
- Department of Chemistry, Laboratory for Organic and Microwave-Assisted Chemistry (LOMAC), KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Stijn Robijns
- Department of Microbial and Molecular Systems, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Kasteelpark Arenberg 20 Box 2460, 3001 Leuven, Belgium
| | - Ami De Weerdt
- Department of Microbial and Molecular Systems, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Kasteelpark Arenberg 20 Box 2460, 3001 Leuven, Belgium
| | - Soňa Kucharíková
- Department of Molecular Microbiology, VIB, KU Leuven, Kasteelpark Arenberg 31 Box 2438, 3001 Leuven, Belgium.,Department of Biology, Laboratory of Molecular Cell Biology, KU Leuven, Kasteelpark Arenberg 31 Box 2438, 3001 Leuven, Belgium
| | - Hélène Tournu
- Department of Molecular Microbiology, VIB, KU Leuven, Kasteelpark Arenberg 31 Box 2438, 3001 Leuven, Belgium.,Department of Biology, Laboratory of Molecular Cell Biology, KU Leuven, Kasteelpark Arenberg 31 Box 2438, 3001 Leuven, Belgium
| | - Annabel Braem
- Department of Materials Engineering (MTM), KU Leuven, Kasteelpark Arenberg 44 Box 2450, 3001 Leuven, Belgium
| | - Katerina Čeh
- Center for Animal Genomics, Veterinary Faculty, University of Ljubljana, Gerbiceva 60, 1000 Ljubljana, Slovenia
| | - Gregor Majdič
- Center for Animal Genomics, Veterinary Faculty, University of Ljubljana, Gerbiceva 60, 1000 Ljubljana, Slovenia
| | - Tanja Španič
- Center for Animal Genomics, Veterinary Faculty, University of Ljubljana, Gerbiceva 60, 1000 Ljubljana, Slovenia
| | - Estera Pogorevc
- Center for Animal Genomics, Veterinary Faculty, University of Ljubljana, Gerbiceva 60, 1000 Ljubljana, Slovenia
| | - Birgit Claes
- Centre for Surface Chemistry and Catalysis, KU Leuven, Kasteelpark Arenberg 23, 3001 Leuven, Belgium
| | | | | | | | | | - Annika Krona
- RISE - Research Institutes of Sweden, Bioscience and Materials, Box 5401, 402 29 Gothenburg, Sweden
| | - Jef Vleugels
- Department of Materials Engineering (MTM), KU Leuven, Kasteelpark Arenberg 44 Box 2450, 3001 Leuven, Belgium
| | - Mirjam Fröhlich
- Educell Ltd., Prevale 9, 1236 Trzin, Slovenia.,Faculty of Medicine, Institute of Cell Biology, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | | | - Katrijn De Brucker
- Department of Microbial and Molecular Systems, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Kasteelpark Arenberg 20 Box 2460, 3001 Leuven, Belgium
| | - Bruno P A Cammue
- Department of Microbial and Molecular Systems, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Kasteelpark Arenberg 20 Box 2460, 3001 Leuven, Belgium.,VIB Center for Plant Systems Biology, Technologiepark 927, 9052 Ghent, Belgium
| | - Karin Thevissen
- Department of Microbial and Molecular Systems, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Kasteelpark Arenberg 20 Box 2460, 3001 Leuven, Belgium
| | - Patrick Van Dijck
- Department of Molecular Microbiology, VIB, KU Leuven, Kasteelpark Arenberg 31 Box 2438, 3001 Leuven, Belgium.,Department of Biology, Laboratory of Molecular Cell Biology, KU Leuven, Kasteelpark Arenberg 31 Box 2438, 3001 Leuven, Belgium
| | - Jozef Vanderleyden
- Department of Microbial and Molecular Systems, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Kasteelpark Arenberg 20 Box 2460, 3001 Leuven, Belgium
| | - Erik Van der Eycken
- Department of Chemistry, Laboratory for Organic and Microwave-Assisted Chemistry (LOMAC), KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Hans P Steenackers
- Department of Microbial and Molecular Systems, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Kasteelpark Arenberg 20 Box 2460, 3001 Leuven, Belgium
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Acquired Nisin Resistance in Staphylococcus aureus Involves Constitutive Activation of an Intrinsic Peptide Antibiotic Detoxification Module. mSphere 2018; 3:3/6/e00633-18. [PMID: 30541781 PMCID: PMC6291627 DOI: 10.1128/mspheredirect.00633-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
NIS and related bacteriocins are of interest as candidates for the treatment of human infections caused by Gram-positive pathogens such as Staphylococcus aureus. An important liability of NIS in this regard is the ease with which S. aureus acquires resistance. Here we establish that this organism naturally possesses the cellular machinery to detoxify NIS but that the ABC transporter responsible (VraDE) is not ordinarily produced to a degree sufficient to yield substantial resistance. Acquired NIS resistance mutations prompt activation of the regulatory circuit controlling expression of vraDE, thereby unmasking an intrinsic resistance determinant. Our results provide new insights into the complex mechanism by which expression of vraDE is regulated and suggest that a potential route to overcoming the resistance liability of NIS could involve chemical modification of the molecule to prevent its recognition by the VraDE transporter. Resistance to the lantibiotic nisin (NIS) arises readily in Staphylococcus aureus as a consequence of mutations in the nsaS gene, which encodes the sensor kinase of the NsaRS two-component regulatory system. Here we present a series of studies to establish how these mutational changes result in reduced NIS susceptibility. Comparative transcriptomic analysis revealed upregulation of the NsaRS regulon in a NIS-resistant mutant of S. aureus versus its otherwise-isogenic progenitor, indicating that NIS resistance mutations prompt gain-of-function in NsaS. Two putative ABC transporters (BraDE and VraDE) encoded within the NsaRS regulon that have been reported to provide a degree of intrinsic protection against NIS were shown to be responsible for acquired NIS resistance; as is the case for intrinsic NIS resistance, NIS detoxification was ultimately mediated by VraDE, with BraDE participating in the signaling cascade underlying VraDE expression. Our study revealed new features of this signal transduction pathway, including that BraDE (but not VraDE) physically interacts with NsaRS. Furthermore, while BraDE has been shown to sense stimuli and signal to NsaS in a process that is contingent upon ATP hydrolysis, we established that this protein complex is also essential for onward transduction of the signal from NsaS through energy-independent means. NIS resistance in S. aureus therefore joins the small number of documented examples in which acquired antimicrobial resistance results from the unmasking of an intrinsic detoxification mechanism through gain-of-function mutation in a regulatory circuit. IMPORTANCE NIS and related bacteriocins are of interest as candidates for the treatment of human infections caused by Gram-positive pathogens such as Staphylococcus aureus. An important liability of NIS in this regard is the ease with which S. aureus acquires resistance. Here we establish that this organism naturally possesses the cellular machinery to detoxify NIS but that the ABC transporter responsible (VraDE) is not ordinarily produced to a degree sufficient to yield substantial resistance. Acquired NIS resistance mutations prompt activation of the regulatory circuit controlling expression of vraDE, thereby unmasking an intrinsic resistance determinant. Our results provide new insights into the complex mechanism by which expression of vraDE is regulated and suggest that a potential route to overcoming the resistance liability of NIS could involve chemical modification of the molecule to prevent its recognition by the VraDE transporter.
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31
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Li B, Maezato Y, Kim SH, Kurihara S, Liang J, Michael AJ. Polyamine-independent growth and biofilm formation, and functional spermidine/spermine N-acetyltransferases in Staphylococcus aureus and Enterococcus faecalis. Mol Microbiol 2018; 111:159-175. [PMID: 30281855 DOI: 10.1111/mmi.14145] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2018] [Indexed: 01/07/2023]
Abstract
Polyamines such as spermidine and spermine are primordial polycations that are ubiquitously present in the three domains of life. We have found that Gram-positive bacteria Staphylococcus aureus and Enterococcus faecalis have lost either all or most polyamine biosynthetic genes, respectively, and are devoid of any polyamine when grown in polyamine-free media. In contrast to bacteria such as Pseudomonas aeruginosa, Campylobacter jejuni and Agrobacterium tumefaciens, which absolutely require polyamines for growth, S. aureus and E. faecalis grow normally over multiple subcultures in the absence of polyamines. Furthermore, S. aureus and E. faecalis form biofilms normally without polyamines, and exogenous polyamines do not stimulate growth or biofilm formation. High levels of external polyamines, including norspermidine, eventually inhibit biofilm formation through inhibition of planktonic growth. We show that spermidine/spermine N-acetyltransferase (SSAT) homologues encoded by S. aureus USA300 and E. faecalis acetylate spermidine, spermine and norspermidine, that spermine is the more preferred substrate, and that E. faecalis SSAT is almost as efficient as human SSAT with spermine as substrate. The polyamine auxotrophy, polyamine-independent growth and biofilm formation, and presence of functional polyamine N-acetyltransferases in S. aureus and E. faecalis represent a new paradigm for bacterial polyamine biology.
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Affiliation(s)
- Bin Li
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yukari Maezato
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sok Ho Kim
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shin Kurihara
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jue Liang
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Anthony J Michael
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
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32
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Genomics of experimental adaptation of Staphylococcus aureus to a natural combination of insect antimicrobial peptides. Sci Rep 2018; 8:15359. [PMID: 30337550 PMCID: PMC6193990 DOI: 10.1038/s41598-018-33593-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/29/2018] [Indexed: 12/25/2022] Open
Abstract
Antimicrobial peptides (AMP) are highly conserved immune effectors across the tree of life and are employed as combinations. In the beetle Tenebrio molitor, a defensin and a coleoptericin are highly expressed in vivo after inoculation with S. aureus. The defensin displays strong in vitro activity but no survival benefit in vivo. The coleoptericin provides a survival benefit in vivo, but no activity in vitro. This suggests a potentiating effect in vivo, and here we wanted to investigate the effects of this combination on resistance evolution using a bottom-approach in vitro starting with a combination of two abundant AMPs only. We experimentally evolved S. aureus in the presence of the defensin and a combination of the defensin and coleoptericin. Genome re-sequencing showed that resistance was associated with mutations in either the pmt or nsa operons. Strains with these mutations show longer lag phases, slower Vmax, and nsa mutants reach lower final population sizes. Mutations in the rpo operon showed a further increase in the lag phase in nsa mutants but not in pmt mutants. In contrast, final MICs (minimum inhibitory concentrations) do not differ according to mutation. All resistant lines display AMP but not antibiotic cross-resistance. Costly resistance against AMPs readily evolves for an individual AMP as well as a naturally occurring combination in vitro and provides broad protection against AMPs. Such non-specific resistance could result in strong selection on host immune systems that rely on cocktails of AMPs.
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33
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Protective immunity in recurrent Staphylococcus aureus infection reflects localized immune signatures and macrophage-conferred memory. Proc Natl Acad Sci U S A 2018; 115:E11111-E11119. [PMID: 30297395 DOI: 10.1073/pnas.1808353115] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Staphylococcus aureus is the leading cause of skin and skin structure infection (SSSI), a primary portal of entry for invasive infection. Our prior studies discovered a role for protective innate memory against recurrent methicillin-resistant S. aureus (MRSA) SSSI. In the present study, the dynamics and mechanisms of this response were explored in recurrent SSSI in WT mice. Priming by prior infection reduced skin lesion severity and MRSA burden, and protected against dissemination at day 7 but not day 2. Cytokine and cellular signatures in SSSI differed at day 2 versus 7, and were distinct in skin versus blood or spleen. Cytokines associated with protection in skin included increased IL-17, IL-6, monokine inducible by IFN-γ (MIG), and RANTES, while increased IP-10 correlated with protection from dissemination. Cellular signatures of protection included increased Th17, M1 macrophage, and dendritic cell populations in abscesses, and total macrophages in lymph nodes. Priming potentiated S. aureus-specific phagocytic killing by bone marrow-derived macrophages in vitro, and their adoptive transfer into naïve skin afforded protective efficacy in vivo. Present findings indicate that protective immunity in recurrent S. aureus infection is locally targeted, and involves specific memory conferred by macrophages. These insights provide targets for vaccine and immunotherapeutic development against MRSA.
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MntC-Dependent Manganese Transport Is Essential for Staphylococcus aureus Oxidative Stress Resistance and Virulence. mSphere 2018; 3:3/4/e00336-18. [PMID: 30021878 PMCID: PMC6052334 DOI: 10.1128/msphere.00336-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Work outlined in this report demonstrated that MntC-dependent manganese transport is required for S. aureus virulence. These study results support the model that MntC-specific antibodies elicited by a vaccine have the potential to disrupt S. aureus manganese transport and thus abrogate to its virulence. Staphylococcus aureus is a human pathogen that has developed several approaches to evade the immune system, including a strategy to resist oxidative killing by phagocytes. This resistance is mediated by production of superoxide dismutase (SOD) enzymes which use manganese as a cofactor. S. aureus encodes two manganese ion transporters, MntABC and MntH, and a possible Nramp family manganese transporter, exemplified by S. aureus N315 SA1432. Their relative contributions to manganese transport have not been well defined in clinically relevant isolates. For this purpose, insertional inactivation mutations were introduced into mntC, mntH, and SA1432 individually and in combination. mntC was necessary for full resistance to methyl viologen, a compound that generates intracellular free radicals. In contrast, strains with an intact mntH gene had a minimal increase in resistance that was revealed only in mntC strains, and no change was observed upon mutation of SA1432 in strains lacking both mntC and mntH. Similarly, MntC alone was required for high cellular SOD activity. In addition, mntC strains were attenuated in a murine sepsis model. To further link these observations to manganese transport, an S. aureus MntC protein lacking manganese binding activity was designed, expressed, and purified. While circular dichroism experiments demonstrated that the secondary and tertiary structures of this protein were unaltered, a defect in manganese binding was confirmed by isothermal titration calorimetry. Unlike complementation with wild-type mntC, introduction of the manganese-binding defective allele into the chromosome of an mntC strain did not restore resistance to oxidative stress or virulence. Collectively, these results underscore the importance of MntC-dependent manganese transport in S. aureus oxidative stress resistance and virulence. IMPORTANCE Work outlined in this report demonstrated that MntC-dependent manganese transport is required for S. aureus virulence. These study results support the model that MntC-specific antibodies elicited by a vaccine have the potential to disrupt S. aureus manganese transport and thus abrogate to its virulence.
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35
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Chung M, Borges V, Gomes JP, de Lencastre H, Tomasz A. Phenotypic signatures and genetic determinants of oxacillin tolerance in a laboratory mutant of Staphylococcus aureus. PLoS One 2018; 13:e0199707. [PMID: 29969476 PMCID: PMC6029783 DOI: 10.1371/journal.pone.0199707] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 06/12/2018] [Indexed: 11/18/2022] Open
Abstract
Addition of β-lactam antibiotics to growing cultures of bacteria inhibit synthesis of the bacterial cell wall peptidoglycan accompanied by killing (loss of viable titer) and lysis (physical disintegration) of the cells. However, it has also been well established that these antibiotics are not effective in killing non-growing or slow-growing bacteria and the mechanism of this "antibiotic tolerance" is not well understood. In this study, we report on the genetic basis and phenotypic properties of an antibiotic tolerant derivative of the methicillin susceptible S. aureus strain 27s. Cultures were exposed to "pulses" of high concentrations of oxacillin followed by outgrowth of the surviving bacteria. This procedure quickly selected for antibiotic tolerant mutants with an increased ability to survive antibiotic treatment without increase in the MIC value for the antibiotic. Such mutants also exhibited longer lag phase, decreased lysis, virtually no change in antibiotic susceptibilities, cross tolerance to D-cycloserine and vancomycin, and increase in biofilm formation in the presence of high concentrations of oxacillin. Whole genome sequencing showed that these altered properties were linked to mutations in the atl and gdpP genes.
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Affiliation(s)
- Marilyn Chung
- Laboratory of Microbiology & Infectious Diseases, The Rockefeller University, New York, New York, United States of America
| | - Vitor Borges
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisboa, Portugal
| | - João Paulo Gomes
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisboa, Portugal
| | - Herminia de Lencastre
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica António Xavier (ITQB) da Universidade Nova de Lisboa, Oeiras, Portugal
| | - Alexander Tomasz
- Laboratory of Microbiology & Infectious Diseases, The Rockefeller University, New York, New York, United States of America
- * E-mail:
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36
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Pollitt EJG, Szkuta PT, Burns N, Foster SJ. Staphylococcus aureus infection dynamics. PLoS Pathog 2018; 14:e1007112. [PMID: 29902272 PMCID: PMC6019756 DOI: 10.1371/journal.ppat.1007112] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 06/26/2018] [Accepted: 05/21/2018] [Indexed: 01/22/2023] Open
Abstract
Staphylococcus aureus is a human commensal that can also cause systemic infections. This transition requires evasion of the immune response and the ability to exploit different niches within the host. However, the disease mechanisms and the dominant immune mediators against infection are poorly understood. Previously it has been shown that the infecting S. aureus population goes through a population bottleneck, from which very few bacteria escape to establish the abscesses that are characteristic of many infections. Here we examine the host factors underlying the population bottleneck and subsequent clonal expansion in S. aureus infection models, to identify underpinning principles of infection. The bottleneck is a common feature between models and is independent of S. aureus strain. Interestingly, the high doses of S. aureus required for the widely used "survival" model results in a reduced population bottleneck, suggesting that host defences have been simply overloaded. This brings into question the applicability of the survival model. Depletion of immune mediators revealed key breakpoints and the dynamics of systemic infection. Loss of macrophages, including the liver Kupffer cells, led to increased sensitivity to infection as expected but also loss of the population bottleneck and the spread to other organs still occurred. Conversely, neutrophil depletion led to greater susceptibility to disease but with a concomitant maintenance of the bottleneck and lack of systemic spread. We also used a novel microscopy approach to examine abscess architecture and distribution within organs. From these observations we developed a conceptual model for S. aureus disease from initial infection to mature abscess. This work highlights the need to understand the complexities of the infectious process to be able to assign functions for host and bacterial components, and why S. aureus disease requires a seemingly high infectious dose and how interventions such as a vaccine may be more rationally developed.
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Affiliation(s)
- Eric J. G. Pollitt
- Department of Molecular Biology and Biotechnology, Firth Court, University of Sheffield, Western Bank, Sheffield, United Kingdom
| | - Piotr T. Szkuta
- Department of Molecular Biology and Biotechnology, Firth Court, University of Sheffield, Western Bank, Sheffield, United Kingdom
| | - Nicola Burns
- Department of Molecular Biology and Biotechnology, Firth Court, University of Sheffield, Western Bank, Sheffield, United Kingdom
| | - Simon J. Foster
- Department of Molecular Biology and Biotechnology, Firth Court, University of Sheffield, Western Bank, Sheffield, United Kingdom
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37
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Gustave CA, Tristan A, Martins-Simões P, Stegger M, Benito Y, Andersen PS, Bes M, Le Hir T, Diep BA, Uhlemann AC, Glaser P, Laurent F, Wirth T, Vandenesch F. Demographic fluctuation of community-acquired antibiotic-resistant Staphylococcus aureus lineages: potential role of flimsy antibiotic exposure. ISME JOURNAL 2018; 12:1879-1894. [PMID: 29599521 DOI: 10.1038/s41396-018-0110-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 03/03/2018] [Accepted: 03/12/2018] [Indexed: 01/28/2023]
Abstract
Community-acquired (CA)- as opposed to hospital acquired- methicillin-resistant Staphylococcus aureus (MRSA) lineages arose worldwide during the 1990s. To determine which factors, including selective antibiotic pressure, govern the expansion of two major lineages of CA-MRSA, namely "USA300" in Northern America and "European ST80" in North Africa, Europe and Middle-East, we explored virulence factor expression, and fitness levels with or without antibiotics. The sampled strains were collected in a temporal window representing various steps of the epidemics, reflecting predicted changes in effective population size as inferred from whole-genome analysis. In addition to slight variations in virulence factor expression and biofilm production that might influence the ecological niches of theses lineages, competitive fitness experiments revealed that the biological cost of resistance to methicillin, fusidic acid and fluoroquinolones is totally reversed in the presence of trace amount of antibiotics. Our results suggest that low-level antibiotics exposure in human and animal environments contributed to the expansion of both European ST80 and USA300 lineages in community settings. This surge was likely driven by antibiotic (ab)use promoting the accumulation of antibiotics as environmental pollutants. The current results provide a novel link between effective population size increase of a pathogen and a selective advantage conferred by antibiotic resistance.
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Affiliation(s)
- Claude-Alexandre Gustave
- CIRI - Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France.,Centre National de Référence des Staphylocoques, Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Anne Tristan
- CIRI - Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France.,Centre National de Référence des Staphylocoques, Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Patricia Martins-Simões
- CIRI - Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France.,Centre National de Référence des Staphylocoques, Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Marc Stegger
- Department for Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Yvonne Benito
- CIRI - Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France.,Centre National de Référence des Staphylocoques, Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Paal Skytt Andersen
- Department for Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark.,Department of Veterinary and Animal Sciences, Frederiksberg, Denmark
| | - Michèle Bes
- CIRI - Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France.,Centre National de Référence des Staphylocoques, Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Typhanie Le Hir
- CIRI - Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France.,Centre National de Référence des Staphylocoques, Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Binh An Diep
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, CA, USA
| | - Anne-Catrin Uhlemann
- Department of Medicine, Division of Infectious Diseases, Columbia University Medical Center, New York City, NY, USA
| | - Philippe Glaser
- Institut Pasteur - APHP - Université Paris Sud, Unité Ecologie et Evolution de la Résistance aux Antibiotiques Paris, France, CNRS UMR3525, Paris, France
| | - Frédéric Laurent
- CIRI - Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France.,Centre National de Référence des Staphylocoques, Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Thierry Wirth
- Institut de Systématique, Evolution, Biodiversité (ISYEB - UMR 7205, CNRS, MNHN, UPMC, EPHE), Muséum National d'Histoire Naturelle, Sorbonne Universités, Paris, France.,EPHE, PSL University, Paris, France
| | - François Vandenesch
- CIRI - Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France. .,Centre National de Référence des Staphylocoques, Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France.
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38
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Lourenço C, Macdonald TJ, Gavriilidis A, Allan E, MacRobert AJ, Parkin IP. Effects of bovine serum albumin on light activated antimicrobial surfaces. RSC Adv 2018; 8:34252-34258. [PMID: 35548657 PMCID: PMC9087004 DOI: 10.1039/c8ra04361b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 09/12/2018] [Indexed: 11/21/2022] Open
Abstract
In this work we demonstrate that our active surfaces still show antibacterial activity even with BSA at low light.
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Affiliation(s)
- Cláudio Lourenço
- Materials Chemistry Research Centre
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
| | - Thomas J. Macdonald
- Materials Chemistry Research Centre
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
| | | | - Elaine Allan
- Division of Microbial Disease
- UCL Eastman Dental Institute University College London
- London
- UK
| | - Alexander J. MacRobert
- Division of Surgery and Interventional Science
- University College London
- Royal Free Campus
- London
- UK
| | - Ivan P. Parkin
- Materials Chemistry Research Centre
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
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39
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Revisiting unexploited antibiotics in search of new antibacterial drug candidates: the case of γ-actinorhodin. Sci Rep 2017; 7:17419. [PMID: 29234001 PMCID: PMC5727142 DOI: 10.1038/s41598-017-17232-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 11/23/2017] [Indexed: 11/20/2022] Open
Abstract
Of the thousands of natural product antibiotics discovered to date, only a handful have been developed for the treatment of bacterial infection. The clinically unexploited majority likely include compounds with untapped potential as antibacterial drugs, and in view of the ever-growing unmet medical need for such agents, warrant systematic re-evaluation. Here we revisit the actinorhodins, a class that was first reported 70 years ago, but which remains poorly characterized. We show that γ-actinorhodin possesses many of the requisite properties of an antibacterial drug, displaying potent and selective bactericidal activity against key Gram-positive pathogens (including Staphylococcus aureus and enterococci), a mode of action distinct from that of other agents in clinical use, an extremely low potential for the development of resistance, and a degree of in vivo efficacy in an invertebrate model of infection. Our findings underscore the utility of revisiting unexploited antibiotics as a source of novel antibacterial drug candidates.
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40
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Sjollema J, van der Mei HC, Hall CL, Peterson BW, de Vries J, Song L, Jong EDD, Busscher HJ, Swartjes JJTM. Detachment and successive re-attachment of multiple, reversibly-binding tethers result in irreversible bacterial adhesion to surfaces. Sci Rep 2017; 7:4369. [PMID: 28663565 PMCID: PMC5491521 DOI: 10.1038/s41598-017-04703-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 05/08/2017] [Indexed: 01/15/2023] Open
Abstract
Bacterial adhesion to surfaces occurs ubiquitously and is initially reversible, though becoming more irreversible within minutes after first contact with a surface. We here demonstrate for eight bacterial strains comprising four species, that bacteria adhere irreversibly to surfaces through multiple, reversibly-binding tethers that detach and successively re-attach, but not collectively detach to cause detachment of an entire bacterium. Arguments build on combining analyses of confined Brownian-motion of bacteria adhering to glass and their AFM force-distance curves and include the following observations: (1) force-distance curves showed detachment events indicative of multiple binding tethers, (2) vibration amplitudes of adhering bacteria parallel to a surface decreased with increasing adhesion-forces acting perpendicular to the surface, (3) nanoscopic displacements of bacteria with relatively long autocorrelation times up to several seconds, in absence of microscopic displacement, (4) increases in Mean-Squared-Displacement over prolonged time periods according to tα with 0 < α ≪ 1, indicative of confined displacement. Analysis of simulated position-maps of adhering particles using a new, in silico model confirmed that adhesion to surfaces is irreversible through detachment and successive re-attachment of reversibly-binding tethers. This makes bacterial adhesion mechanistically comparable with the irreversible adsorption of high-molecular-weight proteins to surfaces, mediated by multiple, reversibly-binding molecular segments.
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Affiliation(s)
- Jelmer Sjollema
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Henny C van der Mei
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
| | - Connie L Hall
- Department of Biomedical Engineering, The College of New Jersey, Armstong Hall, Room 181, P. O. Box 7718, The College of New Jersey, Ewing, NJ, 08628, USA
| | - Brandon W Peterson
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Joop de Vries
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Lei Song
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Ed D de Jong
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Henk J Busscher
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Jan J T M Swartjes
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
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41
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Abstract
Staphylococcus aureus is known to generate small colony variants (SCVs) that are resistant to aminoglycoside antibiotics and can cause persistent and recurrent infections. The SCV phenotype is unstable, and compensatory mutations lead to restored growth, usually with loss of resistance. However, the evolution of improved growth, by mechanisms that avoid loss of antibiotic resistance, is very poorly understood. By selection with serial passaging, we isolated and characterized different classes of extragenic suppressor mutations that compensate for the slow growth of small colony variants. Compensation occurs by two distinct bypass mechanisms: (i) translational suppression of the initial SCV mutation by mutant tRNAs, ribosomal protein S5, or release factor 2 and (ii) mutations that cause the constitutive activation of the SrrAB global transcriptional regulation system. Although compensation by translational suppression increases growth rate, it also reduces antibiotic susceptibility, thus restoring a pseudo-wild-type phenotype. In contrast, an evolutionary pathway that compensates for the SCV phenotype by activation of SrrAB increases growth rate without loss of antibiotic resistance. RNA sequence analysis revealed that mutations activating the SrrAB pathway cause upregulation of genes involved in peptide transport and in the fermentation pathways of pyruvate to generate ATP and NAD+, thus explaining the increased growth. By increasing the growth rate of SCVs without the loss of aminoglycoside resistance, compensatory evolution via the SrrAB activation pathway represents a threat to effective antibiotic therapy of staphylococcal infections.IMPORTANCE Small colony variants (SCVs) of Staphylococcus aureus are a significant clinical problem, causing persistent and antibiotic-resistant infections. However, SCVs are unstable and can rapidly evolve growth-compensated mutants. Previous data suggested that growth compensation only occurred with the loss of antibiotic resistance. We have used selection with serial passaging to uncover four distinct pathways of growth compensation accessible to SCVs. Three of these paths (reversion, intragenic suppression, and translational suppression) increase growth at the expense of losing antibiotic resistance. The fourth path activates an alternative transcriptional program and allows the bacteria to produce the extra ATP required to support faster growth, without losing antibiotic resistance. The importance of this work is that it shows that drug-resistant SCVs can evolve faster growth without losing antibiotic resistance.
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42
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Effect of Antimicrobial and Physical Treatments on Growth of Multispecies Staphylococcal Biofilms. Appl Environ Microbiol 2017; 83:AEM.03483-16. [PMID: 28411222 DOI: 10.1128/aem.03483-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 04/08/2017] [Indexed: 12/18/2022] Open
Abstract
The prevalence and structure of Staphylococcus aureus and Staphylococcus epidermidis within multispecies biofilms were found to depend sensitively on physical environment and antibiotic dosage. Although these species commonly infect similar sites, such as orthopedic implants, little is known about their behavior in multispecies communities, particularly in response to treatment. This research establishes that S. aureus is much more prevalent than S. epidermidis when simultaneously seeded and grown under unstressed conditions (pH 7, 37°C) in both laboratory and clinical strains. In multispecies communities, S. epidermidis is capable of growing a more confluent biofilm when the addition of S. aureus is delayed 4 to 6 h during 18 h of growth. Different vancomycin dosages generate various behaviors: S. epidermidis is more prevalent at a dose of 1.0 μg/ml vancomycin, but reduced growth of both species occurs at 1.9 μg/ml vancomycin. This variability is consistent with the different MICs of S. aureus and S. epidermidis Growth at higher temperature (45°C) results in an environment where S. aureus forms porous biofilms. This porosity allows S. epidermidis to colonize more of the surface, resulting in detectable S. epidermidis biomass. Variations in pH result in increased prevalence of S. epidermidis at low pH (pH 5 and 6), while S. aureus remains dominant at high pH (pH 8 and 9). This work establishes the structural variability of multispecies staphylococcal biofilms as they undergo physical and antimicrobial treatments. It provides a basis for understanding the structure of these communities at infection sites and how treatments disrupt their multispecies behaviors.IMPORTANCEStaphylococcus aureus and Staphylococcus epidermidis are two species of bacteria that are commonly responsible for biofilm infections on medical devices. Biofilms are structured communities of bacteria surrounded by polysaccharides, proteins, and DNA; bacteria are more resistant to antimicrobials as part of a biofilm than as individual cells. This work investigates the structure and prevalence of these two organisms when grown together in multispecies biofilms and shows shifts in the behavior of the polymicrobial community when grown in various concentrations of vancomycin (an antibiotic commonly used to treat staphylococcal infections), in a high-temperature environment (a condition previously shown to lead to cell disruption and death), and at low and high pH (a change that has been previously shown to soften the mechanical properties of staphylococcal biofilms). These shifts in community structure demonstrate the effect such treatments may have on multispecies staphylococcal infections.
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43
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Hoekstra H, Romero Pastrana F, Bonarius HPJ, van Kessel KPM, Elsinga GS, Kooi N, Groen H, van Dijl JM, Buist G. A human monoclonal antibody that specifically binds and inhibits the staphylococcal complement inhibitor protein SCIN. Virulence 2017; 9:70-82. [PMID: 28277903 PMCID: PMC5955450 DOI: 10.1080/21505594.2017.1294297] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Staphylococcus aureus is a serious public health burden causing a wide variety of infections. Earlier detection of such infections could result in faster and more directed therapies that also prevent resistance development. Human monoclonal antibodies (humAbs) are promising tools for diagnosis and therapy owing to their relatively straightforward synthesis, long history of safe clinical use and high target specificity. Here we show that the humAb 6D4, which was obtained from a random screen of B-cells producing antibodies that bind to whole cells of S. aureus, targets the staphylococcal complement inhibitor (SCIN). The epitope recognized by 6D4 was localized to residues 26 to 36 in the N-terminus of SCIN, which overlap with the active site. Accordingly, 6D4 can inhibit SCIN activity as demonstrated through the analysis of C3b deposition on S. aureus cells and complement-induced lysis of rabbit erythrocytes. Importantly, while SCIN is generally regarded as a secreted virulence factor, 6D4 allowed detection of strongly increased SCIN binding to S. aureus cells upon exposure to human serum, relating to the known binding of SCIN to C3 convertases deposited on the staphylococcal cell surface. Lastly, we show that labeling of humAb 6D4 with a near-infrared fluorophore allows one-step detection of SCIN-producing S. aureus cells. Together, our findings show that the newly described humAb 6D4 specifically recognizes S. aureus SCIN, which can potentially be used for detection of human serum-incubated S. aureus strains expressing SCIN.
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Affiliation(s)
- Hedzer Hoekstra
- a Department of Medical Microbiology , University of Groningen, University Medical Center Groningen , Groningen , The Netherlands
| | - Francisco Romero Pastrana
- a Department of Medical Microbiology , University of Groningen, University Medical Center Groningen , Groningen , The Netherlands
| | | | - Kok P M van Kessel
- c Medical Microbiology, University Medical Center Utrecht , Utrecht , The Netherlands
| | | | | | | | - Jan Maarten van Dijl
- a Department of Medical Microbiology , University of Groningen, University Medical Center Groningen , Groningen , The Netherlands
| | - Girbe Buist
- a Department of Medical Microbiology , University of Groningen, University Medical Center Groningen , Groningen , The Netherlands
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44
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Gerits E, Spincemaille P, De Cremer K, De Brucker K, Beullens S, Thevissen K, Cammue BPA, Vandamme K, Fauvart M, Verstraeten N, Michiels J. Repurposing AM404 for the treatment of oral infections by Porphyromonas gingivalis. Clin Exp Dent Res 2017; 3:69-76. [PMID: 29744181 PMCID: PMC5719815 DOI: 10.1002/cre2.65] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 03/04/2017] [Accepted: 03/14/2017] [Indexed: 01/21/2023] Open
Abstract
Porphyromonas gingivalis is a major pathogen involved in oral diseases such as periodontitis and peri‐implantitis. Management of these diseases typically includes mechanical debridement of the colonized surfaces followed by application of antiseptics or antibiotics. Disadvantages associated with the use of antiseptics and the growing worldwide problem of antibiotic resistance have necessitated the search for alternative agents. In this study, the antibacterial and antibiofilm properties of AM404, an active metabolite of paracetamol, were tested against P. gingivalis and other bacterial pathogens. The activity of AM404 was tested against 10 bacteria, including both oral and nonoral human pathogens. The minimal inhibitory concentration (MIC) of AM404 was determined by measuring optical density (OD) values. The minimum biofilm inhibitory concentration (MBIC) was detected by crystal violet staining. The activity of structural analogs of AM404 was tested by MIC determinations. The effect of AM404 on P. gingivalis biofilms formed on titanium disks as a model for dental implants was evaluated by colony forming unit counting. Potential cytotoxicity of AM404 towards HEK‐293 (human embryonic kidney cells), HepG2 (human hepatoma cells), IEC‐6 (rat intestinal cells), and Panc‐1 cells (pancreatic cancer cells) was assessed by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assays. To get more insight in the mode of action of AM404, we used the fluorescent dyes N‐phenyl‐1‐napthylamine and SYTOX green to investigate outer and inner membrane damage of P. gingivalis induced by AM404, respectively. Of all tested pathogens, AM404 only inhibited growth and biofilm formation of P. gingivalis. Moreover, it showed potent activity against P. gingivalis biofilms formed on titanium surfaces. A structure–activity analysis demonstrated that the unsaturated carbon chain is essential for its antibacterial activity. Importantly, AM404 was not toxic towards the tested mammalian cells up to concentrations approaching 4× the MIC. Membrane damage assays using fluorescent probes N‐phenyl‐1‐napthylamine and SYTOX green revealed that membrane permeabilization presumably is the primary antibacterial mode of action of AM404. Collectively, our results suggest that AM404 has the potential to be used for the development of new drugs specifically targeting P. gingivalis‐related infections.
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Affiliation(s)
- Evelien Gerits
- Department of Microbial and Molecular Systems KU Leuven, Centre of Microbial and Plant Genetics Leuven Belgium
| | - Pieter Spincemaille
- Department of Laboratory Medicine University Hospitals Leuven Leuven Belgium
| | - Kaat De Cremer
- Department of Microbial and Molecular Systems KU Leuven, Centre of Microbial and Plant Genetics Leuven Belgium.,Department of Plant Systems Biology VIB Ghent Belgium
| | - Katrijn De Brucker
- Department of Microbial and Molecular Systems KU Leuven, Centre of Microbial and Plant Genetics Leuven Belgium
| | - Serge Beullens
- Department of Microbial and Molecular Systems KU Leuven, Centre of Microbial and Plant Genetics Leuven Belgium
| | - Karin Thevissen
- Department of Microbial and Molecular Systems KU Leuven, Centre of Microbial and Plant Genetics Leuven Belgium
| | - Bruno P A Cammue
- Department of Microbial and Molecular Systems KU Leuven, Centre of Microbial and Plant Genetics Leuven Belgium.,Department of Plant Systems Biology VIB Ghent Belgium
| | - Katleen Vandamme
- Department of Oral Health Sciences UZ Leuven, Restorative Dentistry-KU Leuven, BIOMAT Leuven Belgium
| | - Maarten Fauvart
- Department of Microbial and Molecular Systems KU Leuven, Centre of Microbial and Plant Genetics Leuven Belgium.,Department of Life Science Technologies imec, Smart Systems and Emerging Technologies Unit Belgium
| | - Natalie Verstraeten
- Department of Microbial and Molecular Systems KU Leuven, Centre of Microbial and Plant Genetics Leuven Belgium
| | - Jan Michiels
- Department of Microbial and Molecular Systems KU Leuven, Centre of Microbial and Plant Genetics Leuven Belgium
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45
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Thänert R, Goldmann O, Beineke A, Medina E. Host-inherent variability influences the transcriptional response of Staphylococcus aureus during in vivo infection. Nat Commun 2017; 8:14268. [PMID: 28155859 PMCID: PMC5296661 DOI: 10.1038/ncomms14268] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 12/14/2016] [Indexed: 12/11/2022] Open
Abstract
The rise of antibiotic resistance calls for alternative strategies to treat bacterial infections. One attractive strategy is to directly target bacterial virulence factors with anti-virulence drugs. The expression of virulence traits by pathogens is, however, not constitutive but rather induced by the level of stress encountered within the host. Here we use dual RNA sequencing (RNA-seq) to show that intrinsic variability in the level of host resistance greatly affects the pathogen's transcriptome in vivo. Through analysis of the transcriptional profiles of host and pathogen during Staphylococcus aureus infection of two mouse strains, shown to be susceptible (A/J) or resistant (C57BL/6) to the pathogen, we demonstrate that the expression of virulence factors is dependent on the encountered host resistance. We furthermore provide evidence that this dependence strongly influences the efficacy of anti-virulence strategies, highlighting a potential limitation for the implementation of these strategies. Drugs inhibiting virulence factors of bacterial pathogens are under development. Here, Thänert et al. analyse the transcriptomes of host and pathogen during Staphylococcus aureus infection of two mouse strains, and show that virulence determinants are differentially expressed in different mouse strains.
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Affiliation(s)
- Robert Thänert
- Infection Immunology Research Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Oliver Goldmann
- Infection Immunology Research Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Andreas Beineke
- Institute for Pathology, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany
| | - Eva Medina
- Infection Immunology Research Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
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46
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Abstract
Peptidoglycan (PG), an essential stress-bearing component of the bacterial cell wall, is synthesised by penicillin binding proteins (PBPs). PG synthesis at the cell division septum is necessary for constructing new poles of progeny cells, and cells cannot elongate without inserting new PG in the side-wall. The cell division regulator GpsB appears to co-ordinate PG synthesis at the septum during division and at the side-wall during elongation in rod-shaped and ovococcoid Gram-positive bacteria. How the control over PG synthesis is exerted is unknown. In this issue of Molecular Microbiology, Rued et al. show that in pneumococci GpsB forms complexes with PBP2a and PBP2b, and that deletion or depletion of GpsB prevents closure of the septal ring that in itself is PBP2x-dependent. Loss of GpsB can be suppressed by spontaneous mutations, including within the gene encoding the only PP2C Ser/Thr phosphatase in Streptococcus pneumoniae, indicating that GpsB plays a key - but unknown - role in protein phosphorylation in pneumococci. Rued et al. combine phenotypic and genotypic analyses of mutant strains that suggest discrepancies in the literature concerning GpsB might have arisen from accumulation of unidentified suppressors, highlighting the importance and power of strain validation and whole genome sequencing in this context.
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Affiliation(s)
- Richard J Lewis
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne, NE2 4HH, UK
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47
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Serine-Aspartate Repeat Protein D Increases Staphylococcus aureus Virulence and Survival in Blood. Infect Immun 2016; 85:IAI.00559-16. [PMID: 27795358 PMCID: PMC5203653 DOI: 10.1128/iai.00559-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 10/08/2016] [Indexed: 12/17/2022] Open
Abstract
Staphylococcus aureus expresses a panel of cell wall-anchored adhesins, including proteins belonging to the microbial surface components recognizing adhesive matrix molecule (MSCRAMM) family, exemplified by the serine-aspartate repeat protein D (SdrD), which serve key roles in colonization and infection. Deletion of sdrD from S. aureus subsp. aureus strain NCTC8325-4 attenuated bacterial survival in human whole blood ex vivo, which was associated with increased killing by human neutrophils. Remarkably, SdrD was able to inhibit innate immune-mediated bacterial killing independently of other S. aureus proteins, since addition of recombinant SdrD protein and heterologous expression of SdrD in Lactococcus lactis promoted bacterial survival in human blood. SdrD contributes to bacterial virulence in vivo, since fewer S. aureus subsp. aureus NCTC8325-4 ΔsdrD bacteria than bacteria of the parent strain were recovered from blood and several organs using a murine intravenous infection model. Collectively, our findings reveal a new property of SdrD as an important key contributor to S. aureus survival and the ability to escape the innate immune system in blood.
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48
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Gerits E, Kucharíková S, Van Dijck P, Erdtmann M, Krona A, Lövenklev M, Fröhlich M, Dovgan B, Impellizzeri F, Braem A, Vleugels J, Robijns SCA, Steenackers HP, Vanderleyden J, De Brucker K, Thevissen K, Cammue BPA, Fauvart M, Verstraeten N, Michiels J. Antibacterial activity of a new broad-spectrum antibiotic covalently bound to titanium surfaces. J Orthop Res 2016; 34:2191-2198. [PMID: 27003909 DOI: 10.1002/jor.23238] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/17/2016] [Indexed: 02/04/2023]
Abstract
Biofilm-associated infections, particularly those caused by Staphylococcus aureus, are a major cause of implant failure. Covalent coupling of broad-spectrum antimicrobials to implants is a promising approach to reduce the risk of infections. In this study, we developed titanium substrates on which the recently discovered antibacterial agent SPI031, a N-alkylated 3, 6-dihalogenocarbazol 1-(sec-butylamino)-3-(3,6-dichloro-9H-carbazol-9-yl)propan-2-ol, was covalently linked (SPI031-Ti). We found that SPI031-Ti substrates prevent biofilm formation of S. aureus and Pseudomonas aeruginosa in vitro, as quantified by plate counting and fluorescence microscopy. To test the effectiveness of SPI031-Ti substrates in vivo, we used an adapted in vivo biomaterial-associated infection model in mice in which SPI031-Ti substrates were implanted subcutaneously and subsequently inoculated with S. aureus. Using this model, we found a significant reduction in biofilm formation (up to 98%) on SPI031-Ti substrates compared to control substrates. Finally, we demonstrated that the functionalization of the titanium surfaces with SPI031 did not influence the adhesion and proliferation of human cells important for osseointegration and bone repair. In conclusion, these data demonstrate the clinical potential of SPI031 to be used as an antibacterial coating for implants, thereby reducing the incidence of implant-associated infections. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2191-2198, 2016.
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Affiliation(s)
- Evelien Gerits
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20 box 2460, 3001 Leuven, Belgium
| | - Soňa Kucharíková
- Department of Molecular Microbiology, VIB, KU Leuven, Kasteelpark Arenberg 31 box 2438, 3001 Leuven, Belgium.,Laboratory of Molecular Cell Biology, KU Leuven, Kasteelpark Arenberg 31 box 2438, 3001 Leuven, Belgium
| | - Patrick Van Dijck
- Department of Molecular Microbiology, VIB, KU Leuven, Kasteelpark Arenberg 31 box 2438, 3001 Leuven, Belgium.,Laboratory of Molecular Cell Biology, KU Leuven, Kasteelpark Arenberg 31 box 2438, 3001 Leuven, Belgium
| | | | - Annika Krona
- Department of Structure and Material Design, SP Food and Bioscience, Box 5401, 402 29 Gothenburg, Sweden
| | - Maria Lövenklev
- Department of Structure and Material Design, SP Food and Bioscience, Box 5401, 402 29 Gothenburg, Sweden
| | - Mirjam Fröhlich
- Educell Ltd, Prevale 9, 1236 Trzin, Slovenia.,Faculty of Medicine, Institute of Cell Biology, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | | | | | - Annabel Braem
- Department of Materials Engineering (MTM), KU Leuven, Kasteelpark Arenberg 44 box 2450, 3001 Leuven, Belgium
| | - Jef Vleugels
- Department of Materials Engineering (MTM), KU Leuven, Kasteelpark Arenberg 44 box 2450, 3001 Leuven, Belgium
| | - Stijn C A Robijns
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20 box 2460, 3001 Leuven, Belgium
| | - Hans P Steenackers
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20 box 2460, 3001 Leuven, Belgium
| | - Jozef Vanderleyden
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20 box 2460, 3001 Leuven, Belgium
| | - Katrijn De Brucker
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20 box 2460, 3001 Leuven, Belgium
| | - Karin Thevissen
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20 box 2460, 3001 Leuven, Belgium
| | - Bruno P A Cammue
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20 box 2460, 3001 Leuven, Belgium.,Department of Plant Systems Biology, VIB, Technologiepark 927, 9052 Ghent, Belgium
| | - Maarten Fauvart
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20 box 2460, 3001 Leuven, Belgium.,Department of Life Science Technologies, imec, Smart Systems and Emerging Technologies Unit, Kapeldreef 75, 3001 Leuven, Belgium
| | - Natalie Verstraeten
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20 box 2460, 3001 Leuven, Belgium
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20 box 2460, 3001 Leuven, Belgium
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49
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Broekema NM, Larsen IV, Naruzawa ES, Filutowicz M, Kolb AW, Teixeira LBC, Brandt CR. A Mouse Model of Multi-Drug Resistant Staphylococcus aureus-induced Ocular Disease. ACTA ACUST UNITED AC 2016; 4. [PMID: 27896297 PMCID: PMC5123590 DOI: 10.13188/2334-2838.1000026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Staphylococcus aureus infection of the cornea is a significant threat to vision. The percentage of bacterial isolates resistant to antibiotics is increasing as is the percentage of infections caused by methicillin resistant isolates. There is a critical need for additional therapeutic approaches and their development will require the use of animal models to test efficacy. Two mouse models of S. aureus keratitis have been described but only quantified stromal keratitis (corneal clouding and perforation). We have extended these models using the methicillin resistant S. aureus USA300 LAC strain and show that eyelid inflammation and swelling (blepharitis) and corneal neovascularization can be quantified. This expanded model should prove useful in assessing additional effects of antibacterial therapies and additional pathological mechanisms involved in bacterial ocular infection.
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Affiliation(s)
| | - Inna V Larsen
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Wisconsin, USA
| | | | - Marcin Filutowicz
- Amebagone, Inc.; Department of Bacteriology, University of Wisconsin-Madison, Wisconsin, USA
| | - Aaron W Kolb
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Wisconsin, USA
| | - Leandro B C Teixeira
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Wisconsin, USA
| | - Curtis R Brandt
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Wisconsin, USA; Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Wisconsin, USA; McPherson Eye Research Institute - University of Wisconsin-Madison, Wisconsin, USA
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50
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Modulation of the Substitution Pattern of 5-Aryl-2-Aminoimidazoles Allows Fine-Tuning of Their Antibiofilm Activity Spectrum and Toxicity. Antimicrob Agents Chemother 2016; 60:6483-6497. [PMID: 27550355 PMCID: PMC5075052 DOI: 10.1128/aac.00035-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 08/01/2016] [Indexed: 12/17/2022] Open
Abstract
We previously synthesized several series of compounds, based on the 5-aryl-2-aminoimidazole scaffold, that showed activity preventing the formation of Salmonella enterica serovar Typhimurium and Pseudomonas aeruginosa biofilms. Here, we further studied the activity spectrum of a number of the most active N1- and 2N-substituted 5-aryl-2-aminoimidazoles against a broad panel of biofilms formed by monospecies and mixed species of bacteria and fungi. An N1-substituted compound showed very strong activity against the biofilms formed by Gram-negative and Gram-positive bacteria and the fungus Candida albicans but was previously shown to be toxic against various eukaryotic cell lines. In contrast, 2N-substituted compounds were nontoxic and active against biofilms formed by Gram-negative bacteria and C. albicans but had reduced activity against biofilms formed by Gram-positive bacteria. In an attempt to develop nontoxic compounds with potent activity against biofilms formed by Gram-positive bacteria for application in antibiofilm coatings for medical implants, we synthesized novel compounds with substituents at both the N1 and 2N positions and tested these compounds for antibiofilm activity and toxicity. Interestingly, most of these N1-,2N-disubstituted 5-aryl-2-aminoimidazoles showed very strong activity against biofilms formed by Gram-positive bacteria and C. albicans in various setups with biofilms formed by monospecies and mixed species but lost activity against biofilms formed by Gram-negative bacteria. In light of application of these compounds as anti-infective coatings on orthopedic implants, toxicity against two bone cell lines and the functionality of these cells were tested. The N1-,2N-disubstituted 5-aryl-2-aminoimidazoles in general did not affect the viability of bone cells and even induced calcium deposition. This indicates that modulating the substitution pattern on positions N1 and 2N of the 5-aryl-2-aminoimidazole scaffold allows fine-tuning of both the antibiofilm activity spectrum and toxicity.
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