1
|
Guo R, Fang X, Shang K, Wen J, Ding K. Induction of ferroptosis: A new strategy for the control of bacterial infections. Microbiol Res 2024; 284:127728. [PMID: 38643523 DOI: 10.1016/j.micres.2024.127728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Revised: 04/07/2024] [Accepted: 04/14/2024] [Indexed: 04/23/2024]
Abstract
The continued rise of drug-resistant bacterial infections heightens a threat of a pandemic of antimicrobial resistance to the global health. The urgency of infection control against antimicrobial-resistant bacteria is evident. Ferroptosis, a newly defined form of iron-dependent cell death characterized by lipid peroxidation, has garnered substantial interest since this programmed cell death was associated with pathophysiological processes of many diseases. Exploring whether ferroptosis could be utilized in infectious diseases holds significant importance for discovering novel antimicrobial approaches. Recent years have witnessed significant progress with respect to elucidating the mechanisms that govern ferroptosis induction and its roles in bacterial pathogenesis and host-pathogen interactions. In this review, we discuss the mechanisms of targeting ferroptosis and/or iron homeostasis for the control of antimicrobial-resistant bacterial infections. These implications may inform and enable effective therapeutic strategies against pathogen infection and provide novel insights into the potential applications of ferroptosis to address the global bacterial resistance crisis.
Collapse
Affiliation(s)
- Rongxian Guo
- Laboratory of Functional Microbiology and Animal Health, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471003, China; School of Public Health and Emergency Management, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xin Fang
- School of Public Health and Emergency Management, Southern University of Science and Technology, Shenzhen 518055, China
| | - Ke Shang
- Laboratory of Functional Microbiology and Animal Health, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471003, China
| | - Jiachen Wen
- Key Laboratory of Structure-Based Drugs Design & Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China.
| | - Ke Ding
- Laboratory of Functional Microbiology and Animal Health, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471003, China.
| |
Collapse
|
2
|
Wongdontree P, Millan-Oropeza A, Upfold J, Lavergne JP, Halpern D, Lambert C, Page A, Kénanian G, Grangeasse C, Henry C, Fouet A, Gloux K, Anba-Mondoloni J, Gruss A. Oxidative stress is intrinsic to staphylococcal adaptation to fatty acid synthesis antibiotics. iScience 2024; 27:109505. [PMID: 38577105 PMCID: PMC10993138 DOI: 10.1016/j.isci.2024.109505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 12/08/2023] [Accepted: 03/13/2024] [Indexed: 04/06/2024] Open
Abstract
Antibiotics inhibiting the fatty acid synthesis pathway (FASII) of the major pathogen Staphylococcus aureus reach their enzyme targets, but bacteria continue growth by using environmental fatty acids (eFAs) to produce phospholipids. We assessed the consequences and effectors of FASII-antibiotic (anti-FASII) adaptation. Anti-FASII induced lasting expression changes without genomic rearrangements. Several identified regulators affected the timing of adaptation outgrowth. Adaptation resulted in decreased expression of major virulence factors. Conversely, stress responses were globally increased and adapted bacteria were more resistant to peroxide killing. Importantly, pre-exposure to peroxide led to faster anti-FASII-adaptation by stimulating eFA incorporation. This adaptation differs from reports of peroxide-stimulated antibiotic efflux, which leads to tolerance. In vivo, anti-FASII-adapted S. aureus killed the insect host more slowly but continued multiplying. We conclude that staphylococcal adaptation to FASII antibiotics involves reprogramming, which decreases virulence and increases stress resistance. Peroxide, produced by the host to combat infection, favors anti-FASII adaptation.
Collapse
Affiliation(s)
- Paprapach Wongdontree
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France
| | - Aaron Millan-Oropeza
- PAPPSO Platform, Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Jennifer Upfold
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France
| | - Jean-Pierre Lavergne
- Bacterial Pathogens and Protein Phosphorylation, Molecular Microbiology and Structural Biology, UMR 5086 - CNRS / Université de Lyon, Building IBCP, 7 Passage du Vercors, Lyon, France
| | - David Halpern
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France
| | - Clara Lambert
- Université Paris Cité, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Adeline Page
- Protein Science Facility, SFR BioSciences, CNRS, UMS3444, INSERM US8, Université de Lyon, Lyon, France
| | - Gérald Kénanian
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France
| | - Christophe Grangeasse
- Bacterial Pathogens and Protein Phosphorylation, Molecular Microbiology and Structural Biology, UMR 5086 - CNRS / Université de Lyon, Building IBCP, 7 Passage du Vercors, Lyon, France
| | - Céline Henry
- PAPPSO Platform, Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Agnès Fouet
- Université Paris Cité, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Karine Gloux
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France
| | - Jamila Anba-Mondoloni
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France
| | - Alexandra Gruss
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France
| |
Collapse
|
3
|
Zhu M, Frank MW, Radka CD, Jeanfavre S, Tse MW, Pacheco JA, Pierce K, Deik A, Xu J, Hussain S, Hussain FA, Xulu N, Khan N, Pillay V, Dong KL, Ndung’u T, Clish CB, Rock CO, Blainey PC, Bloom SM, Kwon DS. Vaginal Lactobacillus fatty acid response mechanisms reveal a novel strategy for bacterial vaginosis treatment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.30.573720. [PMID: 38234804 PMCID: PMC10793477 DOI: 10.1101/2023.12.30.573720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Bacterial vaginosis (BV), a common syndrome characterized by Lactobacillus-deficient vaginal microbiota, is associated with adverse health outcomes. BV often recurs after standard antibiotic therapy in part because antibiotics promote microbiota dominance by Lactobacillus iners instead of Lactobacillus crispatus, which has more beneficial health associations. Strategies to promote L. crispatus and inhibit L. iners are thus needed. We show that oleic acid (OA) and similar long-chain fatty acids simultaneously inhibit L. iners and enhance L. crispatus growth. These phenotypes require OA-inducible genes conserved in L. crispatus and related species, including an oleate hydratase (ohyA) and putative fatty acid efflux pump (farE). FarE mediates OA resistance, while OhyA is robustly active in the human vaginal microbiota and sequesters OA in a derivative form that only ohyA-harboring organisms can exploit. Finally, OA promotes L. crispatus dominance more effectively than antibiotics in an in vitro model of BV, suggesting a novel approach for treatment.
Collapse
Affiliation(s)
- Meilin Zhu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
| | - Matthew W. Frank
- Department of Host-Microbe Interactions, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Christopher D. Radka
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky
| | | | - Megan W. Tse
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | - Kerry Pierce
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Amy Deik
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Jiawu Xu
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
| | - Salina Hussain
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
| | - Fatima Aysha Hussain
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Nondumiso Xulu
- HIV Pathogenesis Programme (HPP), The Doris Duke Medical Research Institute, University of KwaZulu-Natal, Durban, South Africa
| | - Nasreen Khan
- HIV Pathogenesis Programme (HPP), The Doris Duke Medical Research Institute, University of KwaZulu-Natal, Durban, South Africa
| | | | - Krista L. Dong
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
- Health Systems Trust, Durban, South Africa
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Thumbi Ndung’u
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
- HIV Pathogenesis Programme (HPP), The Doris Duke Medical Research Institute, University of KwaZulu-Natal, Durban, South Africa
- Africa Health Research Institute (AHRI), Durban, South Africa
- Max Planck Institute for Infection Biology, Berlin, Germany
- Division of Infection and Immunity, University College London, London, UK
| | | | - Charles O. Rock
- Department of Host-Microbe Interactions, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
- passed away on September 22, 2023
| | - Paul C. Blainey
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research at Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Seth M. Bloom
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Douglas S. Kwon
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| |
Collapse
|
4
|
Kuiack RC, Tuffs SW, Dufresne K, Flick R, McCormick JK, McGavin MJ. The fadXDEBA locus of Staphylococcus aureus is required for metabolism of exogenous palmitic acid and in vivo growth. Mol Microbiol 2023; 120:425-438. [PMID: 37501506 DOI: 10.1111/mmi.15131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 07/05/2023] [Accepted: 07/10/2023] [Indexed: 07/29/2023]
Abstract
In Staphylococcus aureus, genes that should confer the capacity to metabolize fatty acids by β-oxidation occur in the fadXDEBA locus, but their function has not been elucidated. Previously, incorporation into phospholipid through the fatty acid kinase FakA pathway was thought to be the only option available for S. aureus to metabolize exogenous saturated fatty acids. We now find that in S. aureus USA300, a fadX::lux reporter was repressed by glucose and induced by palmitic acid but not stearic acid, while in USA300ΔfakA basal expression was significantly elevated, and enhanced in response to both fatty acids. When cultures were supplemented with palmitic acid, palmitoyl-CoA representing the first metabolite in the β-oxidation pathway was detected in USA300, but not in a fadXDEBA deletion mutant USA300Δfad, which relative to USA300 exhibited increased incorporation of palmitic acid into phospholipid accompanied by a rapid loss of viability. USA300Δfad also exhibited significantly reduced viability in a murine tissue abscess infection model. Our data are consistent with FakA-mediated incorporation of fatty acids into phospholipid as a preferred pathway for metabolism of exogenous fatty acids, while the fad locus is critical for metabolism of palmitic acid, which is the most abundant free fatty acid in human plasma.
Collapse
Affiliation(s)
- Robert C Kuiack
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Stephen W Tuffs
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Karine Dufresne
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Robert Flick
- Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - John K McCormick
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
- Lawson Health Research Institute, London, Ontario, Canada
- Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Martin J McGavin
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
- Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
5
|
Jang S. AcrAB-TolC, a major efflux pump in Gram negative bacteria: toward understanding its operation mechanism. BMB Rep 2023; 56:326-334. [PMID: 37254571 PMCID: PMC10315565 DOI: 10.5483/bmbrep.2023-0070] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 05/18/2023] [Accepted: 05/30/2023] [Indexed: 08/27/2023] Open
Abstract
Antibiotic resistance (AR) is a silent pandemic that kills millions worldwide. Although the development of new therapeutic agents against antibiotic resistance is in urgent demand, this has presented a great challenge, especially for Gram-negative bacteria that have inherent drug-resistance mediated by impermeable outer membranes and multidrug efflux pumps that actively extrude various drugs from the bacteria. For the last two decades, multidrug efflux pumps, including AcrAB-TolC, the most clinically important efflux pump in Gram-negative bacteria, have drawn great attention as strategic targets for re-sensitizing bacteria to the existing antibiotics. This article aims to provide a concise overview of the AcrAB-TolC operational mechanism, reviewing its architecture and substrate specificity, as well as the recent development of AcrAB-TolC inhibitors. [BMB Reports 2023; 56(6): 326-334].
Collapse
Affiliation(s)
- Soojin Jang
- Department of Discovery Biology, Antibacterial Resistance Laboratory, Institut Pasteur Korea, Seongnam 13488, Korea
| |
Collapse
|
6
|
Bonn CM, Rafiqullah IM, Crawford JA, Qian YM, Guthrie JL, Matuszewska M, Robinson DA, McGavin MJ. Repeated Emergence of Variant TetR Family Regulator, FarR, and Increased Resistance to Antimicrobial Unsaturated Fatty Acid among Clonal Complex 5 Methicillin-Resistant Staphylococcus aureus. Antimicrob Agents Chemother 2023; 67:e0074922. [PMID: 36744906 PMCID: PMC10019231 DOI: 10.1128/aac.00749-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Resistance-nodulation-division (RND) superfamily efflux pumps promote antibiotic resistance in Gram-negative pathogens, but their role in Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) is undocumented. However, recent in vitro selections for resistance of S. aureus to an antimicrobial fatty acid, linoleic acid, and an antibiotic, rhodomyrtone, identified H121Y and C116R substitution variants, respectively, in a TetR family regulator, FarR, promoting increased expression of the RND pump FarE. Hypothesizing that in vivo selection pressures have also promoted the emergence of FarR variants, we searched available genome data and found that strains with FarRH121Y from human and bovine hosts have emerged sporadically in clonal complexes (CCs) CC1, CC30, CC8, CC22, and CC97, whereas multiple FarR variants have occurred within CC5 hospital-associated (HA)-MRSA. Of these, FarRE160G and FarRE93EE were exclusive to CC5, while FarRC116Y, FarRP165L, and FarRG166D also occurred in nonrelated CCs, primarily from bovine hosts. Within CC5, FarRC116Y and FarRG166D strains were polyphyletic, each exhibiting two emergence events. FarRC116Y and FarRE160G were individually sufficient to confer increased expression of FarE and enhanced resistance to linoleic acid (LA). Isolates with FarRE93EE were most closely related to S. aureus N315 MRSA and exhibited increased resistance independently of FarRE93EE. Accumulation of pseudogenes and additional polymorphisms in FarRE93EE strains contributed to a multiresistance phenotype which included fosfomycin and fusidic acid resistance in addition to increased linoleic acid resistance. These findings underscore the remarkable adaptive capacity of CC5 MRSA, which includes the polyphyletic USA100 lineage of HA-MRSA that is endemic in the Western hemisphere and known for the acquisition of multiple resistance phenotypes.
Collapse
Affiliation(s)
- Camryn M. Bonn
- Department of Microbiology, University of Western Ontario, London, Ontario, Canada
| | - Iftekhar M. Rafiqullah
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - John A. Crawford
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Yi Meng Qian
- Department of Microbiology, University of Western Ontario, London, Ontario, Canada
| | - Jennifer L. Guthrie
- Department of Microbiology, University of Western Ontario, London, Ontario, Canada
- Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Marta Matuszewska
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - D. Ashley Robinson
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi, USA
- Center for Immunology and Microbial Research, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Martin J. McGavin
- Department of Microbiology, University of Western Ontario, London, Ontario, Canada
- Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
7
|
Kengmo Tchoupa A, Kretschmer D, Schittek B, Peschel A. The epidermal lipid barrier in microbiome-skin interaction. Trends Microbiol 2023:S0966-842X(23)00027-6. [PMID: 36822953 DOI: 10.1016/j.tim.2023.01.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 01/24/2023] [Accepted: 01/24/2023] [Indexed: 02/25/2023]
Abstract
The corneocyte layers forming the upper surface of mammalian skin are embedded in a lamellar-membrane matrix which repels harmful molecules while retaining solutes from subcutaneous tissues. Only certain bacterial and fungal taxa colonize skin surfaces. They have ways to use epidermal lipids as nutrients while resisting antimicrobial fatty acids. Skin microorganisms release lipophilic microbe-associated molecular pattern (MAMP) molecules which are largely retained by the epidermal lipid barrier. Skin barrier defects, as in atopic dermatitis, impair lamellar-membrane integrity, resulting in altered skin microbiomes, which then include the pathogen Staphylococcus aureus. The resulting increased penetration of MAMPs and toxins promotes skin inflammation. Elucidating how microorganisms manipulate the epidermal lipid barrier will be key for better ways of preventing inflammatory skin disorders.
Collapse
Affiliation(s)
- Arnaud Kengmo Tchoupa
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany; Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany; German Center for Infection Research (DZIF), partner site Tübingen, Germany
| | - Dorothee Kretschmer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany; Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany; German Center for Infection Research (DZIF), partner site Tübingen, Germany
| | - Birgit Schittek
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany; Dermatology Department, University Hospital Tübingen, Tübingen, Germany
| | - Andreas Peschel
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany; Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany; German Center for Infection Research (DZIF), partner site Tübingen, Germany.
| |
Collapse
|
8
|
Li Y, Guo Z, Xu T, Zhang Y, Zeng L, Huang X, Liu Q. Extracellular vesicles, a novel model linking bacteria to ferroptosis in the future? Appl Microbiol Biotechnol 2022; 106:7377-7386. [PMID: 36216901 DOI: 10.1007/s00253-022-12228-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 10/03/2022] [Accepted: 10/04/2022] [Indexed: 11/29/2022]
Abstract
Ferroptosis is a recently discovered modulated cell death mechanism caused by the accumulation of iron-dependent lipid peroxides to toxic levels and plays an important role in tumor immunology and neurology. Recent studies have shown that ferroptosis may play a crucial role in bacterial infection pathogenesis, which may be useful in anti-infection therapies. However, how bacteria enter cells to induce ferroptosis after invading the host immune system remains largely unknown. In addition, the current studies only focus on the relationship between a single bacterial species or genus and host cell ferroptosis, and there is no systematic summary of its regulatory mechanism. Therefore, our review firstly sums up the role of ferroptosis in bacterial infection and its regulatory mechanism, and innovatively speculates on the function and potential mechanism of extracellular vesicles (EVs) in bacterial-induced ferroptosis, in order to provide possible novel directions and ideas for future anti-infection research. KEY POINTS: • Ferroptosis presents a novel mechanism for bacterial host interaction • EVs provide the potential mechanism for bacterial-induced ferroptosis • The relationship of EVs with ferroptosis provides possible directions for future treatment of bacterial infection.
Collapse
Affiliation(s)
- Yi Li
- Department of Medical Microbiology, School of Medicine, Jiangxi Medical College, Nanchang University, Nanchang, 330006, China.,The First Clinical Medical College, Nanchang University, Nanchang, 30006, China
| | - Zhicheng Guo
- Department of Medical Microbiology, School of Medicine, Jiangxi Medical College, Nanchang University, Nanchang, 330006, China.,The First Clinical Medical College, Nanchang University, Nanchang, 30006, China
| | - Tian Xu
- Department of Medical Microbiology, School of Medicine, Jiangxi Medical College, Nanchang University, Nanchang, 330006, China
| | - Yejia Zhang
- Department of Medical Microbiology, School of Medicine, Jiangxi Medical College, Nanchang University, Nanchang, 330006, China
| | - Lingbing Zeng
- Department of Medical Microbiology, School of Medicine, Jiangxi Medical College, Nanchang University, Nanchang, 330006, China.,The First Clinical Medical College, Nanchang University, Nanchang, 30006, China
| | - Xiaotian Huang
- Department of Medical Microbiology, School of Medicine, Jiangxi Medical College, Nanchang University, Nanchang, 330006, China.
| | - Qiong Liu
- Department of Medical Microbiology, School of Medicine, Jiangxi Medical College, Nanchang University, Nanchang, 330006, China.
| |
Collapse
|
9
|
Dysregulation of Cell Envelope Homeostasis in Staphylococcus aureus Exposed to Solvated Lignin. Appl Environ Microbiol 2022; 88:e0054822. [PMID: 35852361 PMCID: PMC9361832 DOI: 10.1128/aem.00548-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Lignin is an aromatic plant cell wall polymer that facilitates water transport through the vasculature of plants and is generated in large quantities as an inexpensive by-product of pulp and paper manufacturing and biorefineries. Although lignin's ability to reduce bacterial growth has been reported previously, its hydrophobicity complicates the ability to examine its biological effects on living cells in aqueous growth media. We recently described the ability to solvate lignin in Good's buffers with neutral pH, a breakthrough that allowed examination of lignin's antimicrobial effects against the human pathogen Staphylococcus aureus. These analyses showed that lignin damages the S. aureus cell membrane, causes increased cell clustering, and inhibits growth synergistically with tunicamycin, a teichoic acid synthesis inhibitor. In the present study, we examined the physiological and transcriptomic responses of S. aureus to lignin. Intriguingly, lignin restored the susceptibility of genetically resistant S. aureus isolates to penicillin and oxacillin, decreased intracellular pH, impaired normal cell division, and rendered cells more resistant to detergent-induced lysis. Additionally, transcriptome sequencing (RNA-Seq) differential expression (DE) analysis of lignin-treated cultures revealed significant gene expression changes (P < 0.05 with 5% false discovery rate [FDR]) related to the cell envelope, cell wall physiology, fatty acid metabolism, and stress resistance. Moreover, a pattern of concurrent up- and downregulation of genes within biochemical pathways involved in transmembrane transport and cell wall physiology was observed, which likely reflects an attempt to tolerate or compensate for lignin-induced damage. Together, these results represent the first comprehensive analysis of lignin's antibacterial activity against S. aureus. IMPORTANCE S. aureus is a leading cause of skin and soft tissue infections. The ability of S. aureus to acquire genetic resistance to antibiotics further compounds its ability to cause life-threatening infections. While the historical response to antibiotic resistance has been to develop new antibiotics, bacterial pathogens are notorious for rapidly acquiring genetic resistance mechanisms. As such, the development of adjuvants represents a viable way of extending the life span of current antibiotics to which pathogens may already be resistant. Here, we describe the phenotypic and transcriptomic response of S. aureus to treatment with lignin. Our results demonstrate that lignin extracted from sugarcane and sorghum bagasse restores S. aureus susceptibility to β-lactams, providing a premise for repurposing these antibiotics in treatment of resistant S. aureus strains, possibly in the form of topical lignin/β-lactam formulations.
Collapse
|
10
|
Thomasen RSS, Jespersen MG, Jørgensen K, Dos Santos PT, Sternkopf Lillebæk EM, Skov MN, Kemp M, Kallipolitis BH. The Global Regulator CcpA of Listeria monocytogenes Confers Sensitivity to Antimicrobial Fatty Acids. Front Microbiol 2022; 13:895942. [PMID: 35591996 PMCID: PMC9113694 DOI: 10.3389/fmicb.2022.895942] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/15/2022] [Indexed: 11/25/2022] Open
Abstract
Free fatty acids (FFAs) are known to exhibit antimicrobial and anti-virulent properties against bacterial pathogens. Specific FFAs, such as lauric acid (LA; C12:0), exert both effects against the foodborne pathogen Listeria monocytogenes: at low levels, LA acts to inhibit the activity of the virulence regulator PrfA, whereas at higher levels, LA inhibits bacterial growth. Deletion of prfA is known to promote tolerance toward antimicrobial FFAs, suggesting that the response of L. monocytogenes to anti-virulent and antimicrobial FFAs could be linked. In this study, we explored the response of L. monocytogenes toward antimicrobial FFAs holding an anti-virulence activity by isolating strains that can grow at high concentrations of LA. We found that LA-tolerant isolates carry mutations in the gene encoding the global regulator CcpA. Importantly, we discovered that mutation or deletion of ccpA protect L. monocytogenes against the antimicrobial activity of FFAs, whereas the ccpA mutants remain sensitive toward FFA’s PrfA inhibitory effect. A regulatory link involving CcpA, connecting the response toward the antimicrobial and anti-virulence activities of FFAs, is therefore unlikely. To further study how deletion of ccpA promotes FFA tolerance, we performed a transcriptomic analysis of the response to LA. Our data indicated that the FFA-tolerant phenotype of the ∆ccpA strain is not induced upon LA exposure but appears to be an inherent phenotypic trait of the ccpA deletion mutation. Interestingly, we found that the bacterial surface of L. monocytogenes becomes more hydrophilic upon deletion of ccpA, and we demonstrate that CcpA plays a role in the response of L. monocytogenes to other stress conditions, including low pH and antibiotics. Altogether, our study revealed that regulatory activities of CcpA lead to an increased hydrophobicity of the bacterial surface, which may confer sensitivity of L. monocytogenes against the antimicrobial activity of FFAs. Notably, CcpA is not involved in responding to the PrfA inhibitory effect of FFAs, showing that FFA-tolerant strains can still be targeted by the anti-virulent activity of FFAs.
Collapse
Affiliation(s)
- Rikke S S Thomasen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Magnus Ganer Jespersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.,Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| | - Katrine Jørgensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Patricia T Dos Santos
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.,National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Eva M Sternkopf Lillebæk
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Marianne N Skov
- Department of Clinical Microbiology, Odense University Hospital and Research Unit of Clinical Microbiology, University of Southern Denmark, Odense, Denmark
| | - Michael Kemp
- Department of Clinical Microbiology, Odense University Hospital and Research Unit of Clinical Microbiology, University of Southern Denmark, Odense, Denmark.,The Regional Department of Clinical Microbiology, Region Zealand, Zealand University Hospital, Koege, Denmark
| | - Birgitte H Kallipolitis
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| |
Collapse
|
11
|
Thomasen RSS, dos Santos PT, Sternkopf Lillebæk EM, Skov MN, Kemp M, Kallipolitis BH. Absence of N-Acetylglucosamine Glycosylation on Listeria monocytogenes Wall Teichoic Acids Promotes Fatty Acid Tolerance by Repulsion From the Bacterial Surface. Front Microbiol 2022; 13:897682. [PMID: 35633716 PMCID: PMC9133914 DOI: 10.3389/fmicb.2022.897682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 04/27/2022] [Indexed: 11/19/2022] Open
Abstract
Free fatty acids (FFAs) have strong antimicrobial properties against pathogenic bacteria and are known as natural protective agents against bacterial infections. Growth of the foodborne pathogen Listeria monocytogenes is highly affected by the presence of antimicrobial FFAs, however, the response of L. monocytogenes toward FFAs is not fully understood. Here, we explore how L. monocytogenes gains tolerance toward FFAs and present a novel mechanism conferring bacterial protection against FFA toxicity. Strains tolerant against the antimicrobial FFA palmitoleic acid were isolated and whole genome sequenced, and mutations were found in genes involved in wall teichoic acid (WTA) glycosylations. We show that mutation or deletion of lmo1079, which is essential for N-acetylglucosamine (GlcNAc) glycosylation of WTAs, confer tolerance against several antimicrobial FFAs. The FFA tolerant strains are lacking GlcNAc on their WTAs, which result in a more hydrophilic surface. In line with this, we observed a reduced binding of FFAs to the surface of the FFA tolerant strains. Additionally, lack of GlcNAc on WTAs confers tolerance toward acid stress. Altogether, these findings support that GlcNAc modification of WTA plays an important role in the response of L. monocytogenes toward stress conditions encountered during growth as a saprophyte and pathogen, including FFA-rich environments. Most importantly, our data revealed that L. monocytogenes strains lacking GlcNAc on their WTAs are protected against FFA toxicity, because the FFAs are repulsed from the bacterial surface of GlcNAc-deficient strains.
Collapse
Affiliation(s)
- Rikke S. S. Thomasen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Patricia T. dos Santos
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
| | | | - Marianne N. Skov
- Department of Clinical Microbiology, Odense University Hospital and Research Unit of Clinical Microbiology, University of Southern Denmark, Odense, Denmark
| | - Michael Kemp
- Department of Clinical Microbiology, Odense University Hospital and Research Unit of Clinical Microbiology, University of Southern Denmark, Odense, Denmark
- The Regional Department of Clinical Microbiology, Zealand University Hospital, Koege, Denmark
| | - Birgitte H. Kallipolitis
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
- *Correspondence: Birgitte H. Kallipolitis,
| |
Collapse
|
12
|
Sharma S, Singh S, Chaudhary V, Mantri S, Chander A, Maurya R, Rajarammohan S, Singh RP, Rishi P, Bishnoi M, Bhadada SK, Kondepudi KK. Isomaltooligosaccharides utilization and genomic characterization of human infant anti-inflammatory Bifidobacterium longum and Bifidobacterium breve strains. 3 Biotech 2022; 12:89. [PMID: 35299989 PMCID: PMC8901852 DOI: 10.1007/s13205-022-03141-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 02/07/2022] [Indexed: 11/01/2022] Open
Abstract
This study was carried out to understand the probiotic features, ability to utilize non-digestible carbohydrates and comparative genomics of anti-inflammatory Bifidobacterium strains isolated from human infant stool samples. Bacterial strains were isolated from the stool samples using serial dilution on MRS agar plates supplemented with 0.05% l-cysteine hydrochloride and mupirocin. Molecular characterization of the strains was carried out by 16S rRNA gene sequencing. Anti-inflammatory activity was determined using TNF-α and lipopolysaccharide (LPS) induced inflammation in Caco2 cells. Probiotic attributes were determined as per the established protocols. Isomaltooligosaccharides (IMOS) utilization was determined in the broth cultures. Whole genome sequencing and analysis was carried out for three strains. Four obligate anaerobic, Gram positive Bifidobacterium strains were isolated from the infant stool samples. Strains were identified as Bifidobacterium longum Bif10, B. breve Bif11, B. longum Bif12 and B. longum Bif16. The strains were able to prevent inflammation in the Caco2 cells through lowering of IL8 production that was caused by TNF-α and LPS treatment. The strains exhibited desirable probiotic attributes such as acid and bile tolerance, mucin binding, antimicrobial activity, bile salt hydrolase activity, cholesterol lowering ability and could ferment non-digestible carbohydrates such as isomaltooligosaccharides and raffinose. Furthermore, Isomaltooligosaccharides supported the optimum growth of the strains in vitro, which was comparable to that on glucose. Strains could metabolize IMOS through cell associated α-glucosidase activity. Genomic features revealed the presence of genes responsible for the utilization of IMOS and for the probiotic attributes. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-022-03141-2.
Collapse
|
13
|
Hou H, Li Y, Jin Y, Chen S, Long J, Duan G, Yang H. The crafty opponent: the defense systems of Staphylococcus aureus and response measures. Folia Microbiol (Praha) 2022; 67:233-243. [PMID: 35149955 DOI: 10.1007/s12223-022-00954-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 01/29/2022] [Indexed: 11/29/2022]
Abstract
Staphylococcus aureus is a serious threat to public health. S. aureus infection can cause acute or long-term persistent infections that are often resistant to antibiotics and are associated with high morbidity and death. Understanding the defensive systems of S. aureus can help clinicians make the best use of antimicrobial drugs and can also help with antimicrobial stewardship. The mechanisms and clinical implications of S. aureus defense systems, as well as potential response systems, were discussed in this study. Because resistance to all currently available antibiotics is unavoidable, new medicines are always being developed. Alternative techniques, such as anti-virulence and bacteriophage therapies, are being researched and may become major tools in the fight against staphylococcal infections in the future, in addition to the development of new small compounds that affect cell viability.
Collapse
Affiliation(s)
- Hongjie Hou
- Department of Epidemiology, School of Public Health, Zhengzhou University, No. 100 of Science Avenue, Zhengzhou, 450001, China
| | - Yang Li
- Department of Epidemiology, School of Public Health, Zhengzhou University, No. 100 of Science Avenue, Zhengzhou, 450001, China
| | - Yuefei Jin
- Department of Epidemiology, School of Public Health, Zhengzhou University, No. 100 of Science Avenue, Zhengzhou, 450001, China
| | - Shuaiyin Chen
- Department of Epidemiology, School of Public Health, Zhengzhou University, No. 100 of Science Avenue, Zhengzhou, 450001, China
| | - Jinzhao Long
- Department of Epidemiology, School of Public Health, Zhengzhou University, No. 100 of Science Avenue, Zhengzhou, 450001, China
| | - Guangcai Duan
- Department of Epidemiology, School of Public Health, Zhengzhou University, No. 100 of Science Avenue, Zhengzhou, 450001, China
| | - Haiyan Yang
- Department of Epidemiology, School of Public Health, Zhengzhou University, No. 100 of Science Avenue, Zhengzhou, 450001, China.
| |
Collapse
|
14
|
Wassmann CS, Rolsted AP, Lyngsie MC, Puig ST, Kronborg T, Vestergaard M, Ingmer H, Pontoppidan SP, Klitgaard JK. The menaquinone pathway is important for susceptibility of Staphylococcus aureus to the antibiotic adjuvant, cannabidiol. Microbiol Res 2022; 257:126974. [DOI: 10.1016/j.micres.2022.126974] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 01/12/2023]
|
15
|
Dietrich A, Steffens U, Sass P, Bierbaum G. The hypersusceptible antibiotic screening strain Staphylococcus aureus SG511-Berlin harbors multiple mutations in regulatory genes. Int J Med Microbiol 2021; 311:151545. [PMID: 34896903 DOI: 10.1016/j.ijmm.2021.151545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 12/01/2021] [Accepted: 12/05/2021] [Indexed: 10/19/2022] Open
Abstract
The genetic plasticity of Staphylococcus aureus has facilitated the evolution of many virulent and drug-resistant strains. Here we present the sequence of the 2.74 Mbp genome of S. aureus SG511-Berlin, which is frequently used for antibiotic screening. Although S. aureus SG511 and the related methicillin-resistant S. aureus MRSA252 share a high similarity in their core genomes, indicated by an average nucleotide identity (ANI) of 99.83%, the accessory genomes of these strains differed, as nearly no mobile elements and resistance determinants were identified in the genome of S. aureus SG511. Susceptibility testing showed that S. aureus SG511 was susceptible to most of the tested antibiotics of different classes. Intriguingly, and in contrast to the standard laboratory strain S. aureus HG001, S. aureus SG511 was even hyper-susceptible towards cell wall and membrane targeting agents, with the exception of the MurA-inhibitor fosfomycin. In depth comparative genome analysis revealed that, in addition to the loss of function mutation in the antibiotic sensor histidine kinase gene graS, further mutations had occurred in the lysyltransferase gene mprF, the structural giant protein gene ebh, and the regulator genes codY and saeR, which might contribute to antibiotic susceptibility. In addition, an insertion element in agrC abolishes Agr-activity in S. aureus SG511, and the spa and sarS genes, which encode the surface protein SpA and its transcriptional regulator, were deleted. Thus, the lack of mobile resistance genes together with multiple mutations affecting cell envelope morphology may render S. aureus SG511 hyper-susceptible towards most cell wall targeting agents.
Collapse
Affiliation(s)
- Alina Dietrich
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Medical Faculty, 53127 Bonn, Germany.
| | - Ursula Steffens
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Medical Faculty, 53127 Bonn, Germany.
| | - Peter Sass
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Medical Faculty, 53127 Bonn, Germany.
| | - Gabriele Bierbaum
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Medical Faculty, 53127 Bonn, Germany.
| |
Collapse
|
16
|
Transcriptomic responses and survival mechanisms of staphylococci to the antimicrobial skin lipid sphingosine. Antimicrob Agents Chemother 2021; 66:e0056921. [PMID: 34902269 DOI: 10.1128/aac.00569-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sphingosines are antimicrobial lipids that form part of the innate barrier to skin colonisation by microbes. Sphingosine deficiencies can result in increased epithelial infections by bacteria including Staphylococcus aureus. Recent studies have focused on the potential use of sphingosine resistance or its potential mechanisms. We used RNA-Seq to identify the common D-sphingosine transcriptomic response of the transient skin coloniser S. aureus and the dominant skin coloniser S. epidermidis. A common D-sphingosine stimulon was identified that included downregulation of the SaeSR two-component system (TCS) regulon and upregulation of both the VraSR TCS and CtsR stress regulons. We show that the PstSCAB phosphate transporter, and VraSR offer intrinsic resistance to D-sphingosine. Further, we demonstrate increased sphingosine resistance in these staphylococci evolves readily through mutations in genes encoding the FarE-FarR efflux/regulator proteins. The ease of selecting mutants with resistance to sphingosine may impact upon staphylococcal colonisation of skin where the lipid is present and have implications with topical therapeutic applications.
Collapse
|
17
|
Dashtbani-Roozbehani A, Brown MH. Efflux Pump Mediated Antimicrobial Resistance by Staphylococci in Health-Related Environments: Challenges and the Quest for Inhibition. Antibiotics (Basel) 2021; 10:antibiotics10121502. [PMID: 34943714 PMCID: PMC8698293 DOI: 10.3390/antibiotics10121502] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 11/30/2021] [Accepted: 11/30/2021] [Indexed: 01/04/2023] Open
Abstract
The increasing emergence of antimicrobial resistance in staphylococcal bacteria is a major health threat worldwide due to significant morbidity and mortality resulting from their associated hospital- or community-acquired infections. Dramatic decrease in the discovery of new antibiotics from the pharmaceutical industry coupled with increased use of sanitisers and disinfectants due to the ongoing COVID-19 pandemic can further aggravate the problem of antimicrobial resistance. Staphylococci utilise multiple mechanisms to circumvent the effects of antimicrobials. One of these resistance mechanisms is the export of antimicrobial agents through the activity of membrane-embedded multidrug efflux pump proteins. The use of efflux pump inhibitors in combination with currently approved antimicrobials is a promising strategy to potentiate their clinical efficacy against resistant strains of staphylococci, and simultaneously reduce the selection of resistant mutants. This review presents an overview of the current knowledge of staphylococcal efflux pumps, discusses their clinical impact, and summarises compounds found in the last decade from plant and synthetic origin that have the potential to be used as adjuvants to antibiotic therapy against multidrug resistant staphylococci. Critically, future high-resolution structures of staphylococcal efflux pumps could aid in design and development of safer, more target-specific and highly potent efflux pump inhibitors to progress into clinical use.
Collapse
|
18
|
Malwal SR, Oldfield E. Mycobacterial membrane protein Large 3-like-family proteins in bacteria, protozoa, fungi, plants, and animals: A bioinformatics and structural investigation. Proteins 2021; 90:776-790. [PMID: 34739144 DOI: 10.1002/prot.26273] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 10/25/2021] [Indexed: 01/20/2023]
Abstract
Lipid transporters play an important role in most if not all organisms, ranging from bacteria to humans. For example, in Mycobacterium tuberculosis, the trehalose monomycolate transporter MmpL3 is involved in cell wall biosynthesis, while in humans, cholesterol transporters are involved in normal cell function as well as in disease. Here, using structural and bioinformatics information, we propose that there are proteins that also contain "MmpL3-like" (MMPL) transmembrane (TM) domains in many protozoa, including Trypanosoma cruzi, as well as in the bacterium Staphylococcus aureus, where the fatty acid transporter FarE has the same set of "active-site" residues as those found in the mycobacterial MmpL3s, and in T. cruzi. We also show that there are strong sequence and predicted structural similarities between the TM proton-translocation domain seen in the X-ray structures of mycobacterial MmpL3s and several human as well as fungal lipid transporters, leading to the proposal that there are similar proteins in apicomplexan parasites, and in plants. The animal, fungal, apicomplexan, and plant proteins have larger extra-membrane domains than are found in the bacterial MmpL3, but they have a similar TM domain architecture, with the introduction of a (catalytically essential) Phe > His residue change, and a Ser/Thr H-bond network, involved in H+ -transport. Overall, the results are of interest since they show that MMPL-family proteins are present in essentially all life forms: archaea, bacteria, protozoa, fungi, plants and animals and, where known, they are involved in "lipid" (glycolipid, phospholipid, sphingolipid, fatty acid, cholesterol, ergosterol) transport, powered by transmembrane molecular pumps having similar structures.
Collapse
Affiliation(s)
- Satish R Malwal
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Eric Oldfield
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| |
Collapse
|
19
|
Kengmo Tchoupa A, Eijkelkamp BA, Peschel A. Bacterial adaptation strategies to host-derived fatty acids. Trends Microbiol 2021; 30:241-253. [PMID: 34218980 DOI: 10.1016/j.tim.2021.06.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/06/2021] [Accepted: 06/07/2021] [Indexed: 01/08/2023]
Abstract
Fatty acids (FAs) are potent antimicrobials which hold great promise as viable alternatives or complements to conventional antibiotics. Intriguingly, bacteria are well equipped to use environmental FAs as energy sources and/or building blocks for their membrane lipids. Furthermore, these microbes display a wide array of mechanisms to prevent or mitigate FA toxicity. In this review we discuss strategies that bacteria use to thrive despite extensive exposure to host-derived antimicrobial FAs. We also highlight the altered response of these FA-adapted bacteria to antibiotics. Given the ubiquitous nature of FAs in various host environments, deciphering bacterial adaptation strategies to FAs is of prime importance. This knowledge may pave the way for a rational design of FA-based combination therapies with antibiotics.
Collapse
Affiliation(s)
- Arnaud Kengmo Tchoupa
- Department of Infection Biology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany; Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Tübingen, Germany.
| | - Bart A Eijkelkamp
- Molecular Sciences and Technology, College of Science and Engineering, Flinders University, Adelaide, Australia
| | - Andreas Peschel
- Department of Infection Biology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany; Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Tübingen, Germany
| |
Collapse
|
20
|
Ottman N, Barrientos‐Somarribas M, Fyhrquist N, Alexander H, Wisgrill L, Olah P, Tsoka S, Greco D, Levi‐Schaffer F, Soumelis V, Schröder JM, Kere J, Nestle FO, Barker J, Ranki A, Lauerma A, Homey B, Andersson B, Alenius H. Microbial and transcriptional differences elucidate atopic dermatitis heterogeneity across skin sites. Allergy 2021; 76:1173-1187. [PMID: 33001460 PMCID: PMC8246754 DOI: 10.1111/all.14606] [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: 04/22/2020] [Revised: 09/03/2020] [Accepted: 09/06/2020] [Indexed: 12/29/2022]
Abstract
It is well established that different sites in healthy human skin are colonized by distinct microbial communities due to different physiological conditions. However, few studies have explored microbial heterogeneity between skin sites in diseased skin, such as atopic dermatitis (AD) lesions. To address this issue, we carried out deep analysis of the microbiome and transcriptome in the skin of a large cohort of AD patients and healthy volunteers, comparing two physiologically different sites: upper back and posterior thigh. Microbiome samples and biopsies were obtained from both lesional and nonlesional skin to identify changes related to the disease process. Transcriptome analysis revealed distinct disease-related gene expression profiles depending on anatomical location, with keratinization dominating the transcriptomic signatures in posterior thigh, and lipid metabolism in the upper back. Moreover, we show that relative abundance of Staphylococcus aureus is associated with disease severity in the posterior thigh, but not in the upper back. Our results suggest that AD may select for similar microbes in different anatomical locations-an "AD-like microbiome," but distinct microbial dynamics can still be observed when comparing posterior thigh to upper back. This study highlights the importance of considering the variability across skin sites when studying the development of skin inflammation.
Collapse
Affiliation(s)
- Noora Ottman
- Institute of Environmental Medicine Karolinska Institutet Stockholm Sweden
| | | | - Nanna Fyhrquist
- Institute of Environmental Medicine Karolinska Institutet Stockholm Sweden
- Human Microbiome Research Program University of Helsinki Helsinki Finland
| | - Helen Alexander
- St John's Institute of Dermatology Guy's and St Thomas' NHS Foundation Trust and King's College London London UK
| | - Lukas Wisgrill
- Division of Neonatology Pediatric Intensive Care and Neuropediatrics Medical University of Vienna Vienna Austria
| | - Peter Olah
- Department of Dermatology University Hospital Duesseldorf Duesseldorf Germany
- Department of Dermatology, Venereology and Oncodermatology University of Pécs Pécs Hungary
| | - Sophia Tsoka
- Department of Informatics Faculty of Natural and Mathematical Sciences King’s College London London UK
| | - Dario Greco
- Faculty of Medicine and Life Sciences University of Tampere Tampere Finland
- Institute of Biomedical Technology University of Tampere Tampere Finland
- Institute of Biotechnology University of Helsinki Helsinki Finland
| | - Francesca Levi‐Schaffer
- Pharmacology Unit School of Pharmacy Faculty of Medicine The Institute for Drug Research The Hebrew University of Jerusalem Jerusalem Israel
| | | | - Jens M. Schröder
- Department of Dermatology University Hospital Schleswig‐Holstein Kiel Germany
| | - Juha Kere
- Department of Biosciences and Nutrition Karolinska Institutet Stockholm Sweden
- School of Basic and Medical Biosciences King’s College London London UK
| | - Frank O. Nestle
- Cutaneous Medicine Unit St. John’s Institute of Dermatology and Biomedical Research Centre Faculty of Life Sciences and Medicine King’s College London London UK
| | - Jonathan Barker
- St John’s Institute of Dermatology Division of Genetics and Molecular Medicine Faculty of Life Sciences and Medicine Kings College London London UK
| | - Annamari Ranki
- Department of Dermatology, Allergology and Venereology Inflammation Centre University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Antti Lauerma
- Department of Dermatology, Allergology and Venereology Inflammation Centre University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Bernhard Homey
- Department of Dermatology University Hospital Duesseldorf Duesseldorf Germany
| | - Björn Andersson
- Department of Cell and Molecular Biology Karolinska Institutet Stockholm Sweden
| | - Harri Alenius
- Institute of Environmental Medicine Karolinska Institutet Stockholm Sweden
- Human Microbiome Research Program University of Helsinki Helsinki Finland
| |
Collapse
|
21
|
Henderson PJF, Maher C, Elbourne LDH, Eijkelkamp BA, Paulsen IT, Hassan KA. Physiological Functions of Bacterial "Multidrug" Efflux Pumps. Chem Rev 2021; 121:5417-5478. [PMID: 33761243 DOI: 10.1021/acs.chemrev.0c01226] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacterial multidrug efflux pumps have come to prominence in human and veterinary pathogenesis because they help bacteria protect themselves against the antimicrobials used to overcome their infections. However, it is increasingly realized that many, probably most, such pumps have physiological roles that are distinct from protection of bacteria against antimicrobials administered by humans. Here we undertake a broad survey of the proteins involved, allied to detailed examples of their evolution, energetics, structures, chemical recognition, and molecular mechanisms, together with the experimental strategies that enable rapid and economical progress in understanding their true physiological roles. Once these roles are established, the knowledge can be harnessed to design more effective drugs, improve existing microbial production of drugs for clinical practice and of feedstocks for commercial exploitation, and even develop more sustainable biological processes that avoid, for example, utilization of petroleum.
Collapse
Affiliation(s)
- Peter J F Henderson
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Claire Maher
- School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308, New South Wales, Australia
| | - Liam D H Elbourne
- Department of Biomolecular Sciences, Macquarie University, Sydney 2109, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
| | - Bart A Eijkelkamp
- College of Science and Engineering, Flinders University, Bedford Park 5042, South Australia, Australia
| | - Ian T Paulsen
- Department of Biomolecular Sciences, Macquarie University, Sydney 2109, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
| | - Karl A Hassan
- School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
| |
Collapse
|
22
|
Soe YM, Bedoui S, Stinear TP, Hachani A. Intracellular Staphylococcus aureus and host cell death pathways. Cell Microbiol 2021; 23:e13317. [PMID: 33550697 DOI: 10.1111/cmi.13317] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 12/13/2022]
Abstract
Staphylococcus aureus is a major opportunistic human pathogen that is globally prevalent. Although S. aureus and humans may have co-evolved to the point of commensalism, the bacterium is equipped with virulence factors causing devastating infections. The adoption of an intracellular lifestyle by S. aureus is an important facet of its pathogenesis. Occupying a privileged intracellular compartment permits evasion from the bactericidal actions of host immunity and antibiotics. However, this localization exposes S. aureus to cell-intrinsic processes comprising autophagy, metabolic challenges and clearance mechanisms orchestrated by host programmed cell death pathways (PCDs), including apoptosis, pyroptosis and necroptosis. Mounting evidence suggests that S. aureus deploys pathoadaptive mechanisms that modulate the expression of its virulence factors to prevent elimination through PCD pathways. In this review, we critically analyse the current literature on the interplay between S. aureus virulence factors with the key, intertwined nodes of PCD. We discuss how S. aureus adaptation to the human host plays an essential role in the evasion of PCD, and we consider future directions to study S. aureus-PCD interactions.
Collapse
Affiliation(s)
- Ye Mon Soe
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Sammy Bedoui
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Abderrahman Hachani
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| |
Collapse
|
23
|
Abstract
Rhodomyrtone (Rom) is a plant-derived broad-spectrum antibiotic active against many Gram-positive pathogens. A single point mutation in the regulatory farR gene (farR*) confers resistance to Rom in Staphylococcus aureus (RomR). The mutation in farR* alters the activity of the regulator, FarR*, in such a way that not only its own gene, farR*, but also the divergently transcribed farE gene and genes controlled by the global regulator, agr, are highly upregulated. Here, we show that mainly the upregulation of the fatty acid efflux pump FarE causes the RomR phenotype, as farE deletion in either the parent or the RomR strain (RomR ΔfarE) yielded hypersensitivity to Rom. Comparative lipidome analysis of the supernatant (exolipidomics) and the pellet fraction revealed that the RomR strain excreted about 10 times more phospholipids (PGs) than the parent strain or the ΔfarE mutants. Since the PG content in the supernatant (2,244 ng/optical density [OD]) was more than 100-fold higher than that of fatty acids (FA), we assumed that PG interacts with Rom, thereby abrogating its antimicrobial activity. Indeed, by static and dynamic light scattering (SLS and DLS) and isothermal titration calorimetry (ITC) analyses, we could demonstrate that both PG and Rom were vesicular and reacted with each other in milliseconds to form a 1:1.49 [Rom-PG(32:0), where PG(32:0) is PG with C32:0 lipids] complex. The binding is entropically driven and hence hydrophobic and of low specificity in nature. Our results indicate that the cytoplasmic membrane is the actual target of Rom, which is also in agreement with Rom's induced rapid collapse of the membrane potential and decreased membrane integrity. IMPORTANCE Antibiotic resistance is a growing public health problem, and alternative antibiotics are urgently needed. Rhodomyrtone (Rom), an antimicrobial compound originally isolated from Rhodomyrtus tomentosa, is active against multidrug-resistant Gram-positive pathogens. However, Rom-resistant (RomR) mutants occur with low frequency. In this study, we unraveled the underlying resistance mechanism, which is based on a point mutation in the farR regulator gene, causing overexpression of FarE, which most likely acts as a phospholipid (PG) efflux pump, as large amounts of PG were found in the supernatant and the pellet fraction. We show that PG can bind to Rom, thereby abrogating its antimicrobial activity. The direct interaction of Rom with PG suggests that Rom's actual target is the cytoplasmic membrane. Antibiotics that interact with PG are rare. Since Rom can be chemically synthesized, it serves as a lead compound for synthesis of improved variants.
Collapse
|
24
|
Pidwill GR, Gibson JF, Cole J, Renshaw SA, Foster SJ. The Role of Macrophages in Staphylococcus aureus Infection. Front Immunol 2021; 11:620339. [PMID: 33542723 PMCID: PMC7850989 DOI: 10.3389/fimmu.2020.620339] [Citation(s) in RCA: 119] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 12/02/2020] [Indexed: 12/23/2022] Open
Abstract
Staphylococcus aureus is a member of the human commensal microflora that exists, apparently benignly, at multiple sites on the host. However, as an opportunist pathogen it can also cause a range of serious diseases. This requires an ability to circumvent the innate immune system to establish an infection. Professional phagocytes, primarily macrophages and neutrophils, are key innate immune cells which interact with S. aureus, acting as gatekeepers to contain and resolve infection. Recent studies have highlighted the important roles of macrophages during S. aureus infections, using a wide array of killing mechanisms. In defense, S. aureus has evolved multiple strategies to survive within, manipulate and escape from macrophages, allowing them to not only subvert but also exploit this key element of our immune system. Macrophage-S. aureus interactions are multifaceted and have direct roles in infection outcome. In depth understanding of these host-pathogen interactions may be useful for future therapeutic developments. This review examines macrophage interactions with S. aureus throughout all stages of infection, with special emphasis on mechanisms that determine infection outcome.
Collapse
Affiliation(s)
- Grace R Pidwill
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom.,Florey Institute, University of Sheffield, Sheffield, United Kingdom
| | - Josie F Gibson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom.,Florey Institute, University of Sheffield, Sheffield, United Kingdom.,The Bateson Centre, University of Sheffield, Sheffield, United Kingdom
| | - Joby Cole
- Florey Institute, University of Sheffield, Sheffield, United Kingdom.,Department of Infection, Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Stephen A Renshaw
- Florey Institute, University of Sheffield, Sheffield, United Kingdom.,The Bateson Centre, University of Sheffield, Sheffield, United Kingdom.,Department of Infection, Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Simon J Foster
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom.,Florey Institute, University of Sheffield, Sheffield, United Kingdom
| |
Collapse
|
25
|
Novel Functions and Signaling Specificity for the GraS Sensor Kinase of Staphylococcus aureus in Response to Acidic pH. J Bacteriol 2020; 202:JB.00219-20. [PMID: 32868405 DOI: 10.1128/jb.00219-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 08/26/2020] [Indexed: 01/30/2023] Open
Abstract
Although the GraS sensor kinase of Staphylococcus aureus is known for the sensing of and resistance to cationic antimicrobial peptides (CAMPs), we recently established that it also signals in response to acidic pH, which is encountered on human skin concurrently with CAMPs, antimicrobial unsaturated free fatty acids (uFFA), and calcium. We therefore evaluated how these environmental signals would affect GraS function and resistance to antimicrobial uFFA. Growth at pH 5.5 promoted increased resistance of S. aureus USA300 to linoleic and arachidonic acids but not palmitoleic or sapienic acid. However, enhanced resistance to these C16:1 uFFA was achieved by supplementing acidic medium with 0.5 mM calcium or subinhibitory CAMPs. Enhanced resistance to uFFA at acidic pH was dependent on GraS and GraS-dependent expression of the lysyl-phosphatidylglycerol synthase enzyme MprF, through a mechanism that did not require the lysyl-transferase function of MprF. In addition to enhanced resistance to antimicrobial uFFA, acidic pH also promoted increased production of secreted proteases in a GraS-dependent manner. During growth at pH 5.5, downstream phenotypes of signaling through GraS, including resistance to uFFA, MprF-dependent addition of positive charge to the cell surface, and increased production of secreted proteases, all occurred independently of acidic amino acids in the extracytoplasmic sensor loop of GraS that were previously found to be required for sensing of CAMPs. Cumulatively, our data indicate that signaling through GraS at acidic pH occurs through a mechanism that is distinct from that described for CAMPs, leading to increased resistance to antimicrobial uFFA and production of secreted proteases.IMPORTANCE Staphylococcus aureus asymptomatically colonizes 30% of humans but is also a leading cause of infectious morbidity and mortality. Since infections are typically initiated by the same strain associated with asymptomatic colonization of the nose or skin, it is important to understand how the microbe can endure exposure to harsh conditions that successfully restrict the growth of other bacteria, including a combination of acidic pH, antimicrobial peptides, and antimicrobial fatty acids. The significance of our research is in showing that acidic pH combined with antimicrobial peptide or environmental calcium can signal through a single membrane sensor protein to promote traits that may aid in survival, including modification of cell surface properties, increased resistance to antimicrobial fatty acids, and enhanced production of secreted proteases.
Collapse
|
26
|
Abstract
The nares of one in three humans are colonized by Staphylococcus aureus. In these environments, and arguably on all mucosal surfaces, bacteria encounter fatty acids with antimicrobial properties. Our study uncovers that S. aureus releases membrane vesicles (MVs) that act as decoys to protect the bacterium against antimicrobial fatty acids (AFAs). The AFA-neutralizing effects of MVs were neither strain specific nor restricted to one particular AFA. Hence, MVs may represent “public goods” playing an overlooked role in shaping bacterial communities in AFA-rich environments such as the skin and nose. Intriguingly, in addition to MV biogenesis, S. aureus modulates MV composition in response to exposure to AFAs, including an increased release of lipoproteins. These MVs strongly stimulate the innate immunity via Toll-like receptor 2 (TLR2). TLR2-mediated inflammation, which helps to fight infections, may exacerbate inflammatory disorders like atopic dermatitis. Our study highlights intricate immune responses preventing infections from colonizing bacteria. Staphylococcus aureus is a major pathogen, which colonizes one in three otherwise healthy humans. This significant spread of S. aureus is largely due to its ability to circumvent innate immune responses, including antimicrobial fatty acids (AFAs) on the skin and in nasal secretions. In response to AFAs, S. aureus swiftly induces resistance mechanisms, which have yet to be completely elucidated. Here, we identify membrane vesicle (MV) release as a resistance strategy used by S. aureus to sequester host-specific AFAs. MVs protect S. aureus against a wide array of AFAs. Strikingly, beside MV production, S. aureus modulates MV composition upon exposure to AFAs. MVs purified from bacteria grown in the presence of linoleic acid display a distinct protein content and are enriched in lipoproteins, which strongly activate Toll-like receptor 2 (TLR2). Cumulatively, our findings reveal the protective capacities of MVs against AFAs, which are counteracted by an increased TLR2-mediated innate immune response. IMPORTANCE The nares of one in three humans are colonized by Staphylococcus aureus. In these environments, and arguably on all mucosal surfaces, bacteria encounter fatty acids with antimicrobial properties. Our study uncovers that S. aureus releases membrane vesicles (MVs) that act as decoys to protect the bacterium against antimicrobial fatty acids (AFAs). The AFA-neutralizing effects of MVs were neither strain specific nor restricted to one particular AFA. Hence, MVs may represent “public goods” playing an overlooked role in shaping bacterial communities in AFA-rich environments such as the skin and nose. Intriguingly, in addition to MV biogenesis, S. aureus modulates MV composition in response to exposure to AFAs, including an increased release of lipoproteins. These MVs strongly stimulate the innate immunity via Toll-like receptor 2 (TLR2). TLR2-mediated inflammation, which helps to fight infections, may exacerbate inflammatory disorders like atopic dermatitis. Our study highlights intricate immune responses preventing infections from colonizing bacteria.
Collapse
|
27
|
Kénanian G, Morvan C, Weckel A, Pathania A, Anba-Mondoloni J, Halpern D, Gaillard M, Solgadi A, Dupont L, Henry C, Poyart C, Fouet A, Lamberet G, Gloux K, Gruss A. Permissive Fatty Acid Incorporation Promotes Staphylococcal Adaptation to FASII Antibiotics in Host Environments. Cell Rep 2020; 29:3974-3982.e4. [PMID: 31851927 DOI: 10.1016/j.celrep.2019.11.071] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 10/01/2019] [Accepted: 11/15/2019] [Indexed: 02/08/2023] Open
Abstract
The essentiality of fatty acid synthesis (FASII) products in the human pathogen Staphylococcus aureus is the underlying rationale for FASII-targeted antimicrobial drug design. Reports of anti-FASII efficacy in animals support this choice. However, restricted test conditions used previously led us to investigate this postulate in a broader, host-relevant context. We report that S. aureus rapidly adapts to FASII antibiotics without FASII mutations when exposed to host environments. FASII antibiotic administration upon signs of infection, rather than just after inoculation as commonly practiced, fails to eliminate S. aureus in a septicemia model. In vitro, serum lowers S. aureus membrane stress, leading to a greater retention of the substrates required for environmental fatty acid (eFA) utilization: eFAs and the acyl carrier protein. In this condition, eFA occupies both phospholipid positions, regardless of anti-FASII selection. Our results identify S. aureus membrane plasticity in host environments as a main limitation for using FASII antibiotics in monotherapeutic treatments.
Collapse
Affiliation(s)
- Gérald Kénanian
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Claire Morvan
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Antonin Weckel
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, 75014 Paris, France
| | - Amit Pathania
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Jamila Anba-Mondoloni
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - David Halpern
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Marine Gaillard
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, 75014 Paris, France
| | - Audrey Solgadi
- SAMM, UMS IPSIT, Faculté de Pharmacie, Université Paris-Saclay, Chatenay-Malabry, France
| | - Laetitia Dupont
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Céline Henry
- PAPPSO Platform, Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Claire Poyart
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, 75014 Paris, France; Centre National de Référence des Streptocoques, Hôpitaux Universitaires Paris Centre Site Cochin, APHP, Paris, France
| | - Agnès Fouet
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, 75014 Paris, France
| | - Gilles Lamberet
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Karine Gloux
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Alexandra Gruss
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France.
| |
Collapse
|
28
|
The type VII secretion system protects Staphylococcus aureus against antimicrobial host fatty acids. Sci Rep 2020; 10:14838. [PMID: 32908165 PMCID: PMC7481793 DOI: 10.1038/s41598-020-71653-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/17/2020] [Indexed: 02/06/2023] Open
Abstract
The Staphylococcus aureus type VII secretion system (T7SS) exports several proteins that are pivotal for bacterial virulence. The mechanisms underlying T7SS-mediated staphylococcal survival during infection nevertheless remain unclear. Here we report that S. aureus lacking T7SS components are more susceptible to host-derived antimicrobial fatty acids. Unsaturated fatty acids such as linoleic acid (LA) elicited an increased inhibition of S. aureus mutants lacking T7SS effectors EsxC, EsxA and EsxB, or the membrane-bound ATPase EssC, compared to the wild-type (WT). T7SS mutants generated in different S. aureus strain backgrounds also displayed an increased sensitivity to LA. Analysis of bacterial membrane lipid profiles revealed that the esxC mutant was less able to incorporate LA into its membrane phospholipids. Although the ability to bind labelled LA did not differ between the WT and mutant strains, LA induced more cell membrane damage in the T7SS mutants compared to the WT. Furthermore, proteomic analyses of WT and mutant cell fractions revealed that, in addition to compromising membranes, T7SS defects induce oxidative stress and hamper their response to LA challenge. Thus, our findings indicate that T7SS contribute to maintaining S. aureus membrane integrity and homeostasis when bacteria encounter antimicrobial fatty acids.
Collapse
|
29
|
Tiwari KB, Gatto C, Wilkinson BJ. Plasticity of Coagulase-Negative Staphylococcal Membrane Fatty Acid Composition and Implications for Responses to Antimicrobial Agents. Antibiotics (Basel) 2020; 9:E214. [PMID: 32354049 PMCID: PMC7277709 DOI: 10.3390/antibiotics9050214] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 04/18/2020] [Accepted: 04/27/2020] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus demonstrates considerable membrane lipid plasticity in response to different growth environments, which is of potential relevance to response and resistance to various antimicrobial agents. This information is not available for various species of coagulase-negative staphylococci, which are common skin inhabitants, can be significant human pathogens, and are resistant to multiple antibiotics. We determined the total fatty acid compositions of Staphylococcus auricularis, Staphylococcus capitis, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus saprophyticus, and Staphylococcus aureus for comparison purposes. Different proportions of branched-chain and straight-chain fatty acids were observed amongst the different species. However, growth in cation-supplemented Mueller-Hinton broth significantly increased the proportion of branched-chain fatty acids, and membrane fluidities as measured by fluorescence anisotropy. Cation-supplemented Mueller-Hinton broth is used for routine determination of antimicrobial susceptibilities. Growth in serum led to significant increases in straight-chain unsaturated fatty acids in the total fatty acid profiles, and decreases in branched-chain fatty acids. This indicates preformed fatty acids can replace biosynthesized fatty acids in the glycerolipids of coagulase-negative staphylococci, and indicates that bacterial fatty acid biosynthesis system II may not be a good target for antimicrobial agents in these organisms. Even though the different species are expected to be exposed to skin antimicrobial fatty acids, they were susceptible to the major skin antimicrobial fatty acid sapienic acid (C16:1Δ6). Certain species were not susceptible to linoleic acid (C18:2Δ9,12), but no obvious relationship to fatty acid composition could be discerned.
Collapse
Affiliation(s)
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, IL 61761, USA
| | - Brian J. Wilkinson
- School of Biological Sciences, Illinois State University, Normal, IL 61761, USA
| |
Collapse
|
30
|
Epidemiology of efflux pumps genes mediating resistance among Staphylococcus aureus; A systematic review. Microb Pathog 2019; 139:103850. [PMID: 31706002 DOI: 10.1016/j.micpath.2019.103850] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 10/22/2019] [Accepted: 11/05/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND Efflux of antibiotics is an effective resistance mechanism among antibiotic-resistant Staphylococcus aureus. This systematic review aims to evaluate the frequency and expression of efflux pump genes in S.aureus around the world. METHOD A comprehensive literature search of several databases (Medline Pub Med, ISI, Scopus, Google Scholar, ISC, Science direct and Persian Journals Online, and citation lists) was performed. We considered published studies from 2001 to 2018. Articles reporting the prevalence and expression of efflux pump genes were selected. RESULT Among 183 articles, 36 studies were selected. Of the 36, 23 articles were conducted in Asia.6 in Europe, 5 in America and 2 in African countries. In most of these studies norA, norB, qacA/B genes were commonly evaluated by molecular methods. The presence of efflux pump genes such as norA, norB, norC, mepA, mdeA, qacA/B was detected by PCR in 21 studies and over-expression of genes were reported in 13 studies. The most frequently reported genes in Asia were norA (75%), norB (60%), mepA (35%), mdeA (33%) and qacA/B (20.8%). In European studies, the prevalence of norB was mostly reported among S.aureus isolates and norA and qacA/B were commonly found in similar studies in America. The investigation of gene expression patterns showed that norA was most frequent single-pattern in Asia and America, norB or mdeA in Europe. CONCLUSION According to this study MDR efflux pumps not only cause high-level resistance but also it considerably associated with over-expression of these genes. Due to the selective pressure on MRSA isolate, the enormous diversity of plasmid-encoded genes had been recorded in different regions, owing to the various numbers and types of isolates in each study or types of disinfectants for general use.
Collapse
|
31
|
Beavers WN, Monteith AJ, Amarnath V, Mernaugh RL, Roberts LJ, Chazin WJ, Davies SS, Skaar EP. Arachidonic Acid Kills Staphylococcus aureus through a Lipid Peroxidation Mechanism. mBio 2019; 10:e01333-19. [PMID: 31575763 PMCID: PMC6775451 DOI: 10.1128/mbio.01333-19] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 08/21/2019] [Indexed: 01/14/2023] Open
Abstract
Staphylococcus aureus infects every niche of the human host. In response to microbial infection, vertebrates have an arsenal of antimicrobial compounds that inhibit bacterial growth or kill bacterial cells. One class of antimicrobial compounds consists of polyunsaturated fatty acids, which are highly abundant in eukaryotes and encountered by S. aureus at the host-pathogen interface. Arachidonic acid (AA) is one of the most abundant polyunsaturated fatty acids in vertebrates and is released in large amounts during the oxidative burst. Most of the released AA is converted to bioactive signaling molecules, but, independently of its role in inflammatory signaling, AA is toxic to S. aureus Here, we report that AA kills S. aureus through a lipid peroxidation mechanism whereby AA is oxidized to reactive electrophiles that modify S. aureus macromolecules, eliciting toxicity. This process is rescued by cotreatment with antioxidants as well as in a S. aureus strain genetically inactivated for lcpA (USA300 ΔlcpA mutant) that produces lower levels of reactive oxygen species. However, resistance to AA stress in the USA300 ΔlcpA mutant comes at a cost, making the mutant more susceptible to β-lactam antibiotics and attenuated for pathogenesis in a murine infection model compared to the parental methicillin-resistant S. aureus (MRSA) strain, indicating that resistance to AA toxicity increases susceptibility to other stressors encountered during infection. This report defines the mechanism by which AA is toxic to S. aureus and identifies lipid peroxidation as a pathway that can be modulated for the development of future therapeutics to treat S. aureus infections.IMPORTANCE Despite the ability of the human immune system to generate a plethora of molecules to control Staphylococcus aureus infections, S. aureus is among the pathogens with the greatest impact on human health. One class of host molecules toxic to S. aureus consists of polyunsaturated fatty acids. Here, we investigated the antibacterial properties of arachidonic acid, one of the most abundant polyunsaturated fatty acids in humans, and discovered that the mechanism of toxicity against S. aureus proceeds through lipid peroxidation. A better understanding of the molecular mechanisms by which the immune system kills S. aureus, and by which S. aureus avoids host killing, will enable the optimal design of therapeutics that complement the ability of the vertebrate immune response to eliminate S. aureus infections.
Collapse
Affiliation(s)
- William N Beavers
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Andrew J Monteith
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Venkataraman Amarnath
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Raymond L Mernaugh
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - L Jackson Roberts
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Walter J Chazin
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Sean S Davies
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA
| |
Collapse
|
32
|
Nguyen MT, Saising J, Tribelli PM, Nega M, Diene SM, François P, Schrenzel J, Spröer C, Bunk B, Ebner P, Hertlein T, Kumari N, Härtner T, Wistuba D, Voravuthikunchai SP, Mäder U, Ohlsen K, Götz F. Inactivation of farR Causes High Rhodomyrtone Resistance and Increased Pathogenicity in Staphylococcus aureus. Front Microbiol 2019; 10:1157. [PMID: 31191485 PMCID: PMC6547885 DOI: 10.3389/fmicb.2019.01157] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 05/07/2019] [Indexed: 12/22/2022] Open
Abstract
Rhodomyrtone (Rom) is an acylphloroglucinol antibiotic originally isolated from leaves of Rhodomyrtus tomentosa. Rom targets the bacterial membrane and is active against a wide range of Gram-positive bacteria but the exact mode of action remains obscure. Here we isolated and characterized a spontaneous Rom-resistant mutant from the model strain Staphylococcus aureus HG001 (RomR) to learn more about the resistance mechanism. We showed that Rom-resistance is based on a single point mutation in the coding region of farR [regulator of fatty acid (FA) resistance] that causes an amino acid change from Cys to Arg at position 116 in FarR, that affects FarR activity. Comparative transcriptome analysis revealed that mutated farR affects transcription of many genes in distinct pathways. FarR represses for example the expression of its own gene (farR), its flanking gene farE (effector of FA resistance), and other global regulators such as agr and sarA. All these genes were consequently upregulated in the RomR clone. Particularly the upregulation of agr and sarA leads to increased expression of virulence genes rendering the RomR clone more cytotoxic and more pathogenic in a mouse infection model. The Rom-resistance is largely due to the de-repression of farE. FarE is described as an efflux pump for linoleic and arachidonic acids. We observed an increased release of lipids in the RomR clone compared to its parental strain HG001. If farE is deleted in the RomR clone, or, if native farR is expressed in the RomR strain, the corresponding strains become hypersensitive to Rom. Overall, we show here that the high Rom-resistance is mediated by overexpression of farE in the RomR clone, that FarR is an important regulator, and that the point mutation in farR (RomR clone) makes the clone hyper-virulent.
Collapse
Affiliation(s)
- Minh-Thu Nguyen
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany.,Federal Regulatory Agency for Vaccines and Biomedicines, Paul Ehrlich Institute, Langen, Germany
| | - Jongkon Saising
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany.,School of Health Science, Mae Fah Luang University, Chiang Rai, Thailand
| | - Paula Maria Tribelli
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany.,Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales - Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Mulugeta Nega
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany
| | - Seydina M Diene
- Genomic Research Laboratory, Service of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland
| | - Patrice François
- Genomic Research Laboratory, Service of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland
| | - Jacques Schrenzel
- Genomic Research Laboratory, Service of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland
| | - Cathrin Spröer
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Boyke Bunk
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Patrick Ebner
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany
| | - Tobias Hertlein
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Nimerta Kumari
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany
| | - Thomas Härtner
- Microbiology/Biotechnology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany
| | - Dorothee Wistuba
- Institute for Organic Chemistry, University of Tübingen, Tübingen, Germany
| | - Supayang P Voravuthikunchai
- Department of Microbiology, Natural Product Centre of Excellence, Prince of Songkla University, Hat Yai, Thailand
| | - Ulrike Mäder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Knut Ohlsen
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Friedrich Götz
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany
| |
Collapse
|
33
|
Subramanian C, Frank MW, Batte JL, Whaley SG, Rock CO. Oleate hydratase from Staphylococcus aureus protects against palmitoleic acid, the major antimicrobial fatty acid produced by mammalian skin. J Biol Chem 2019; 294:9285-9294. [PMID: 31018965 DOI: 10.1074/jbc.ra119.008439] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/11/2019] [Indexed: 01/01/2023] Open
Abstract
Oleate hydratases (OhyAs) belong to a large family of bacterial proteins catalyzing the hydration or isomerization of double bonds in unsaturated fatty acids. A Staphylococcus aureus gene (Sa0102) is predicted to encode an OhyA. Here, we recombinantly expressed and purified SaOhyA and found that it forms a homodimer that requires FAD for activity. SaOhyA hydrates only unsaturated fatty acids containing cis-9 double bonds, but not fatty acids with trans-9 double bonds or cis double bonds at other positions. SaOhyA products were not detected in S. aureus phospholipids and were released into the growth medium. S. aureus does not synthesize unsaturated fatty acids, and the SaOhyA substrates are derived from infection sites. Palmitoleate (16:1(9Z)) is a major mammalian skin-produced antimicrobial fatty acid that protects against S. aureus infection, and we observed that it is an SaOhyA substrate and that its hydroxylated derivative is not antimicrobial. Treatment of S. aureus with 24 μm 16:1(9Z) immediately arrested growth, followed by growth resumption after a lag period of 2 h. The ΔohyA mutant strain did not recover from the 16:1(9Z) challenge, and increasing SaOhyA expression using a plasmid system prevented the initial growth arrest. Challenging S. aureus with sapienic acid (16:1(6Z)), an antimicrobial fatty acid produced only by human skin, arrested growth without recovery in WT, ΔohyA, and SaOhyA-overexpressing strains. We conclude that SaOhyA protects S. aureus from palmitoleic acid, the antimicrobial unsaturated fatty acid produced by most mammals, and that sapienic acid, uniquely produced by humans, counters the OhyA-dependent bacterial defense mechanism.
Collapse
Affiliation(s)
- Chitra Subramanian
- From the Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Matthew W Frank
- From the Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Justin L Batte
- From the Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Sarah G Whaley
- From the Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Charles O Rock
- From the Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| |
Collapse
|
34
|
DNA Binding and Sensor Specificity of FarR, a Novel TetR Family Regulator Required for Induction of the Fatty Acid Efflux Pump FarE in Staphylococcus aureus. J Bacteriol 2019; 201:JB.00602-18. [PMID: 30455282 DOI: 10.1128/jb.00602-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 11/12/2018] [Indexed: 12/18/2022] Open
Abstract
Divergent genes in Staphylococcus aureus USA300 encode the efflux pump FarE and TetR family regulator FarR, which confer resistance to antimicrobial unsaturated fatty acids. To study their regulation, we constructed USA300 ΔfarER, which exhibited a 2-fold reduction in MIC of linoleic acid. farE expressed from its native promoter on pLIfarE conferred increased resistance to USA300 but not USA300 ΔfarER Complementation of USA300 ΔfarER with pLIfarR also had no effect, whereas resistance was restored with pLIfarER or through ectopic expression of farE In electrophoretic mobility shift assays, FarR bound to three different oligonucleotide probes that each contained a TAGWTTA motif, occurring as (i) a singular motif overlapping the -10 element of the P farR promoter, (ii) in palindrome PAL1 immediately in the 3' direction of P farR , or (iii) within PAL2 upstream of the predicted P farE promoter. FarR autorepressed its expression through cooperative binding to PAL1 and the adjacent TAGWTTA motif in P farR Consistent with reports that S. aureus does not metabolize fatty acids through acyl coenzyme A (acyl-CoA) intermediates, DNA binding activity of FarR was not affected by linoleoyl-CoA. Conversely, induction of farE required fatty acid kinase FakA, which catalyzes the first metabolic step in the incorporation of unsaturated fatty acids into phospholipid. We conclude that FarR is needed to promote the expression of farE while strongly autorepressing its own expression, and our data are consistent with a model whereby FarR interacts with a FakA-dependent product of exogenous fatty acid metabolism to ensure that efflux only occurs when the metabolic capacity for incorporation of fatty acid into phospholipid is exceeded.IMPORTANCE Here, we describe the DNA binding and sensor specificity of FarR, a novel TetR family regulator (TFR) in Staphylococcus aureus Unlike the majority of TFRs that have been characterized, which function to repress a divergently transcribed gene, we find that FarR is needed to promote expression of the divergently transcribed farE gene, encoding a resistance-nodulation-division (RND) family efflux pump that is induced in response to antimicrobial unsaturated fatty acids. Induction of farE was dependent on the function of the fatty acid kinase FakA, which catalyzes the first metabolic step in the incorporation of exogenous unsaturated fatty acids into phospholipid. This represents a novel example of TFR function.
Collapse
|
35
|
Gajenthra Kumar N, Contaifer D, Baker PRS, Ekroos K, Jefferson KK, Wijesinghe DS. Untargeted lipidomic analysis to broadly characterize the effects of pathogenic and non-pathogenic staphylococci on mammalian lipids. PLoS One 2018; 13:e0206606. [PMID: 30379915 PMCID: PMC6209338 DOI: 10.1371/journal.pone.0206606] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 10/16/2018] [Indexed: 11/19/2022] Open
Abstract
Modification of the host lipidome via secreted enzymes is an integral, but often overlooked aspect of bacterial pathogenesis. In the current era of prevalent antibiotic resistance, knowledge regarding critical host pathogen lipid interactions has the potential for use in developing novel antibacterial agents. While most studies to date on this matter have focused on specific lipids, or select lipid classes, this provides an incomplete picture. Modern methods of untargeted lipidomics have the capacity to overcome these gaps in knowledge and provide a comprehensive understanding of the role of lipid metabolism in the pathogenesis of infections. In an attempt to determine the role of lipid modifying enzymes produced by staphylococci, we exposed bovine heart lipids, a standardized model for the mammalian lipidome, to spent medium from staphylococcal cultures, and analyzed lipid molecular changes by MS/MSALL shotgun lipidomics. We elucidate distinct effects of different staphylococcal isolates, including 4 clinical isolates of the pathogenic species Staphylococcus aureus, a clinical isolate of the normally commensal species S. epidermidis, and the non-pathogenic species S. carnosus. Two highly virulent strains of S. aureus had a more profound effect on mammalian lipids and modified more lipid classes than the other staphylococcal strains. Our studies demonstrate the utility of the applied untargeted lipidomics methodology to profile lipid changes induced by different bacterial secretomes. Finally, we demonstrate the promise of this lipidomics approach in assessing the specificity of bacterial enzymes for mammalian lipid classes. Our data suggests that there may be a correlation between the bacterial expression of lipid-modifying enzymes and virulence, and could facilitate the guided discovery of lipid pathways required for bacterial infections caused by S. aureus and thereby provide insights into the generation of novel antibacterial agents.
Collapse
Affiliation(s)
- Naren Gajenthra Kumar
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Daniel Contaifer
- Department of Pharmacotherapy and Outcomes Sciences, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | | | - Kim Ekroos
- Lipidomics Consulting Ltd., Esbo, Finland
| | - Kimberly K. Jefferson
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Dayanjan S. Wijesinghe
- Department of Pharmacotherapy and Outcomes Sciences, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, United States of America
| |
Collapse
|
36
|
Lekshmi M, Ammini P, Adjei J, Sanford LM, Shrestha U, Kumar S, Varela MF. Modulation of antimicrobial efflux pumps of the major facilitator superfamily in Staphylococcus aureus. AIMS Microbiol 2018; 4:1-18. [PMID: 31294201 PMCID: PMC6605029 DOI: 10.3934/microbiol.2018.1.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/19/2017] [Indexed: 12/15/2022] Open
Abstract
Variants of the microorganism Staphylococcus aureus which are resistant to antimicrobial agents exist as causative agents of serious infectious disease and constitute a considerable public health concern. One of the main antimicrobial resistance mechanisms harbored by S. aureus pathogens is exemplified by integral membrane transport systems that actively remove antimicrobial agents from bacteria where the cytoplasmic drug targets reside, thus allowing the bacteria to survive and grow. An important class of solute transporter proteins, called the major facilitator superfamily, includes related and homologous passive and secondary active transport systems, many of which are antimicrobial efflux pumps. Transporters of the major facilitator superfamily, which confer antimicrobial efflux and bacterial resistance in S. aureus, are good targets for development of resistance-modifying agents, such as efflux pump inhibition. Such modulatory action upon these antimicrobial efflux systems of the major facilitator superfamily in S. aureus may circumvent resistance and restore the clinical efficacy of therapy towards S. aureus infection.
Collapse
Affiliation(s)
- Manjusha Lekshmi
- QC Laboratory, Harvest and Post Harvest Technology Division, ICAR-Central Institute of Fisheries Education (CIFE), Seven Bungalows, Versova, Andheri (W), Mumbai, 400061, India
| | - Parvathi Ammini
- CSIR-National Institute of Oceanography (NIO), Regional Centre, Dr. Salim Ali Road, Kochi, 682018, India
| | - Jones Adjei
- Eastern New Mexico, Department of Biology, Station 33, 1500 South Avenue K, Portales, NM, 88130, USA
| | - Leslie M Sanford
- Eastern New Mexico, Department of Biology, Station 33, 1500 South Avenue K, Portales, NM, 88130, USA
| | - Ugina Shrestha
- Eastern New Mexico, Department of Biology, Station 33, 1500 South Avenue K, Portales, NM, 88130, USA
| | - Sanath Kumar
- QC Laboratory, Harvest and Post Harvest Technology Division, ICAR-Central Institute of Fisheries Education (CIFE), Seven Bungalows, Versova, Andheri (W), Mumbai, 400061, India
| | - Manuel F Varela
- Eastern New Mexico, Department of Biology, Station 33, 1500 South Avenue K, Portales, NM, 88130, USA
| |
Collapse
|
37
|
Christo-Foroux E, Vallaeys T, Loux V, Dassa E, Deutscher J, Wandersman C, Livernois A, Hot C, Criscuolo A, Dauga C, Clermont D, Chesneau O. Manual and expert annotation of the nearly complete genome sequence of Staphylococcus sciuri strain ATCC 29059: A reference for the oxidase-positive staphylococci that supports the atypical phenotypic features of the species group. Syst Appl Microbiol 2017; 40:401-410. [PMID: 28890241 DOI: 10.1016/j.syapm.2017.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 06/30/2017] [Accepted: 07/03/2017] [Indexed: 11/30/2022]
Abstract
Staphylococcus sciuri is considered to be one of the most ancestral species in the natural history of the Staphylococcus genus that consists of 48 validly described species. It belongs to the basal group of oxidase-positive and novobiocin-resistant staphylococci that diverged from macrococci approximately 250 million years ago. Contrary to other groups, the S. sciuri species group has not developed host-specific colonization strategies. Genome analysis of S. sciuri ATCC 29059 provides here the first genetic basis for atypical traits that would support the switch between the free-living style and the infective state in animals and humans. From among the most remarkable features, it was noticed in this extensive study that there were a number of phosphoenolpyruvate:carbohydrate phosphotransferase systems (PTS), almost twice as many as any other staphylococci, and the co-occurrence of mevalonate and non-mevalonate pathways for isoprenoid synthesis. The sequenced strain was devoid of the main virulence factors present in Staphylococcus aureus, although it exhibited numerous heme and iron acquisition systems, as well as crt and aldH genes necessary for gold pigment synthesis. The sensing and signaling networks, exemplified by a large and typical repertoire of two-component regulatory systems and a complete panel of master regulators, such as agr, rex, mgrA, rot, sarA and sarR genes, depict the background in which S. aureus virulence genes were later acquired. An additional sigma factor, a distinct set of electron transducer elements and many gene operons similar to those found in Bacillus spp. would constitute the most visible remnant links with Bacillaceae organisms.
Collapse
Affiliation(s)
- Eugene Christo-Foroux
- Département de Microbiologie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
| | - Tatiana Vallaeys
- Département de Biologie Ecologie, Université de Montpellier, CC 13002, Place Eugène Bataillon, 34095 Montpellier, France.
| | - Valentin Loux
- MaIAGE, INRA, Université Paris-Saclay, Domaine de Vilvert, 78352 Jouy-en-Josas, France.
| | - Elie Dassa
- Département de Microbiologie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Josef Deutscher
- CNRS, UMR 8261 Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Université Paris Diderot, Sorbonne-Paris-Cité, 13 rue Pierre et Marie Curie, Paris, France.
| | - Cécile Wandersman
- Département de Microbiologie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Aurélien Livernois
- Département de Microbiologie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France; Département de Biologie Ecologie, Université de Montpellier, CC 13002, Place Eugène Bataillon, 34095 Montpellier, France
| | - Chloe Hot
- Département de Microbiologie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Alexis Criscuolo
- Hub, Center for Bioinformatics, Biostatistics and Integrative Biology (C3BI), Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
| | - Catherine Dauga
- International Group of Data Analysis (IGDA), Center for Bioinformatics, Biostatistics and Integrative Biology (C3BI), Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
| | - Dominique Clermont
- Collection de l'Institut Pasteur (CIP), Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
| | - Olivier Chesneau
- Département de Microbiologie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
| |
Collapse
|
38
|
Spengler G, Kincses A, Gajdács M, Amaral L. New Roads Leading to Old Destinations: Efflux Pumps as Targets to Reverse Multidrug Resistance in Bacteria. Molecules 2017; 22:molecules22030468. [PMID: 28294992 PMCID: PMC6155429 DOI: 10.3390/molecules22030468] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 01/05/2023] Open
Abstract
Multidrug resistance (MDR) has appeared in response to selective pressures resulting from the incorrect use of antibiotics and other antimicrobials. This inappropriate application and mismanagement of antibiotics have led to serious problems in the therapy of infectious diseases. Bacteria can develop resistance by various mechanisms and one of the most important factors resulting in MDR is efflux pump-mediated resistance. Because of the importance of the efflux-related multidrug resistance the development of new therapeutic approaches aiming to inhibit bacterial efflux pumps is a promising way to combat bacteria having over-expressed MDR efflux systems. The definition of an efflux pump inhibitor (EPI) includes the ability to render the bacterium increasingly more sensitive to a given antibiotic or even reverse the multidrug resistant phenotype. In the recent years numerous EPIs have been developed, although so far their clinical application has not yet been achieved due to their in vivo toxicity and side effects. In this review, we aim to give a short overview of efflux mediated resistance in bacteria, EPI compounds of plant and synthetic origin, and the possible methods to investigate and screen EPI compounds in bacterial systems.
Collapse
Affiliation(s)
- Gabriella Spengler
- Department of Medical Microbiology and Immunobiology, Faculty of Medicine, University of Szeged, 6720 Szeged, Hungary.
| | - Annamária Kincses
- Department of Medical Microbiology and Immunobiology, Faculty of Medicine, University of Szeged, 6720 Szeged, Hungary.
| | - Márió Gajdács
- Department of Medical Microbiology and Immunobiology, Faculty of Medicine, University of Szeged, 6720 Szeged, Hungary.
| | - Leonard Amaral
- Department of Medical Microbiology and Immunobiology, Faculty of Medicine, University of Szeged, 6720 Szeged, Hungary.
- Travel Medicine, Institute of Hygiene and Tropical Medicine, Universidade Nova de Lisboa, 1349-008 Lisbon, Portugal.
| |
Collapse
|
39
|
Blodkamp S, Kadlec K, Gutsmann T, Quiblier C, Naim HY, Schwarz S, von Köckritz-Blickwede M. Effects of SecDF on the antimicrobial functions of cathelicidins against Staphylococcus aureus. Vet Microbiol 2017; 200:52-58. [DOI: 10.1016/j.vetmic.2016.03.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 03/29/2016] [Accepted: 03/30/2016] [Indexed: 10/22/2022]
|
40
|
García-Gómez E, Jaso-Vera ME, Juárez-Verdayes MA, Alcántar-Curiel MD, Zenteno JC, Betanzos-Cabrera G, Peralta H, Rodríguez-Martínez S, Cancino-Díaz ME, Jan-Roblero J, Cancino-Diaz JC. The 95ΔG mutation in the 5'untranslated region of the norA gene increases efflux activity in Staphylococcus epidermidis isolates. Microb Pathog 2016; 103:139-148. [PMID: 28017900 DOI: 10.1016/j.micpath.2016.12.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 12/17/2016] [Accepted: 12/19/2016] [Indexed: 12/25/2022]
Abstract
In the Staphylococcus aureus ATCC25923 strain, the flqB mutation in the 5'untranslated region (5'UTR) of the norA gene causes increased norA mRNA expression and high efflux activity (HEA). The involvement of the norA gene 5'UTR in HEA has not been explored in S. epidermidis; therefore, we examined the function of this region in S. epidermidis clinical isolates. The selection of isolates with HEA was performed based on ethidium bromide (EtBr) MIC values and efflux efficiency (EF) using the semi-automated fluorometric method. The function of the 5'UTR was studied by quantifying the levels of norA expression (RT-qPCR) and by identifying 5'UTR mutations by sequence analysis. Only 10 isolates from a total of 165 (6.1%) had HEA (EtBr MIC = 300 μg/ml and EF ranged from 48.4 to 97.2%). Eight of 10 isolates with HEA had the 5'UTR 95ΔG mutation. Isolates carrying the 95ΔG mutation had higher levels of norA expression compared with those that did not. To corroborate that the 95ΔG mutation is involved in HEA, a strain adapted to EtBr was obtained in vitro. This strain also presented the 95ΔG mutation and had a high level of norA expression and EF, indicating that the 95ΔG mutation is important for the HEA phenotype. The 95ΔG mutation produces a different structure in the Shine-Dalgarno region, which may promote better translation of norA mRNA. To our knowledge, this is the first report to demonstrate the participation of the 5'UTR 95ΔG mutation of the norA gene in the HEA phenotype of S. epidermidis isolates. Here, we propose that the efflux of EtBr is caused by an increment in the transcription and/or translation of the norA gene.
Collapse
Affiliation(s)
- Elizabeth García-Gómez
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Marcos E Jaso-Vera
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Marco A Juárez-Verdayes
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Ciudad de México, Mexico
| | | | - Juan C Zenteno
- Instituto de Oftalmología Fundación Conde de Valenciana, Ciudad de México, Mexico
| | - Gabriel Betanzos-Cabrera
- Área Académica de Nutrición, Instituto de Ciencias de la Salud, Universidad Autónoma del Estado de Hidalgo, Pachuca, Hidalgo, Mexico
| | - Humberto Peralta
- Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Sandra Rodríguez-Martínez
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Mario E Cancino-Díaz
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Janet Jan-Roblero
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Juan C Cancino-Diaz
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas-Instituto Politécnico Nacional, Ciudad de México, Mexico.
| |
Collapse
|
41
|
Schindler BD, Kaatz GW. Multidrug efflux pumps of Gram-positive bacteria. Drug Resist Updat 2016; 27:1-13. [DOI: 10.1016/j.drup.2016.04.003] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/28/2016] [Accepted: 04/22/2016] [Indexed: 11/16/2022]
|
42
|
The Pseudomonas aeruginosa efflux pump MexGHI-OpmD transports a natural phenazine that controls gene expression and biofilm development. Proc Natl Acad Sci U S A 2016; 113:E3538-47. [PMID: 27274079 DOI: 10.1073/pnas.1600424113] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Redox-cycling compounds, including endogenously produced phenazine antibiotics, induce expression of the efflux pump MexGHI-OpmD in the opportunistic pathogen Pseudomonas aeruginosa Previous studies of P. aeruginosa virulence, physiology, and biofilm development have focused on the blue phenazine pyocyanin and the yellow phenazine-1-carboxylic acid (PCA). In P. aeruginosa phenazine biosynthesis, conversion of PCA to pyocyanin is presumed to proceed through the intermediate 5-methylphenazine-1-carboxylate (5-Me-PCA), a reactive compound that has eluded detection in most laboratory samples. Here, we apply electrochemical methods to directly detect 5-Me-PCA and find that it is transported by MexGHI-OpmD in P. aeruginosa strain PA14 planktonic and biofilm cells. We also show that 5-Me-PCA is sufficient to fully induce MexGHI-OpmD expression and that it is required for wild-type colony biofilm morphogenesis. These physiological effects are consistent with the high redox potential of 5-Me-PCA, which distinguishes it from other well-studied P. aeruginosa phenazines. Our observations highlight the importance of this compound, which was previously overlooked due to the challenges associated with its detection, in the context of P. aeruginosa gene expression and multicellular behavior. This study constitutes a unique demonstration of efflux-based self-resistance, controlled by a simple circuit, in a Gram-negative pathogen.
Collapse
|
43
|
Jamrozy DM, Harris SR, Mohamed N, Peacock SJ, Tan CY, Parkhill J, Anderson AS, Holden MTG. Pan-genomic perspective on the evolution of the Staphylococcus aureus USA300 epidemic. Microb Genom 2016; 2:e000058. [PMID: 28348852 PMCID: PMC5320670 DOI: 10.1099/mgen.0.000058] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 03/29/2016] [Accepted: 04/04/2016] [Indexed: 12/16/2022] Open
Abstract
Staphylococcus aureus USA300 represents the dominant community-associated methicillin-resistant S. aureus lineage in the USA, where it is a major cause of skin and soft tissue infections. Previous comparative genomic studies have described the population structure and evolution of USA300 based on geographically restricted isolate collections. Here, we investigated the USA300 population by sequencing genomes of a geographically distributed panel of 191 clinical S. aureus isolates belonging to clonal complex 8 (CC8), derived from the Tigecycline Evaluation and Surveillance Trial program. Isolates were collected at 12 healthcare centres across nine USA states in 2004, 2009 or 2010. Reconstruction of evolutionary relationships revealed that CC8 was dominated by USA300 isolates (154/191, 81 %), which were heterogeneous and demonstrated limited phylogeographic clustering. Analysis of the USA300 core genomes revealed an increase in median pairwise SNP distance from 62 to 98 between 2004 and 2010, with a stable pattern of above average dN/dS ratios. The phylogeny of the USA300 population indicated that early diversification events led to the formation of nested clades, which arose through cumulative acquisition of predominantly non-synonymous SNPs in various coding sequences. The accessory genome of USA300 was largely homogenous and consisted of elements previously associated with this lineage. We observed an emergence of SCCmec negative and ACME negative USA300 isolates amongst more recent samples, and an increase in the prevalence of ϕSa5 prophage. Together, the analysed S. aureus USA300 collection revealed an evolving pan-genome through increased core genome heterogeneity and temporal variation in the frequency of certain accessory elements.
Collapse
Affiliation(s)
| | | | - Naglaa Mohamed
- Pfizer Vaccine Research and Development, Pearl River, New York, USA
| | - Sharon J. Peacock
- The Wellcome Trust Sanger Institute, Cambridge CB10 1SA, UK
- London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Charles Y. Tan
- Pfizer Vaccine Research and Development, Pearl River, New York, USA
| | | | | | | |
Collapse
|
44
|
Jang S. Multidrug efflux pumps in Staphylococcus aureus and their clinical implications. J Microbiol 2016; 54:1-8. [DOI: 10.1007/s12275-016-5159-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 10/29/2015] [Accepted: 10/30/2015] [Indexed: 12/13/2022]
|
45
|
Kato A, Use K, Takatani N, Ikeda K, Matsuura M, Kojima K, Aichi M, Maeda SI, Omata T. Modulation of the balance of fatty acid production and secretion is crucial for enhancement of growth and productivity of the engineered mutant of the cyanobacterium Synechococcus elongatus. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:91. [PMID: 27110287 PMCID: PMC4841976 DOI: 10.1186/s13068-016-0506-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 04/12/2016] [Indexed: 05/16/2023]
Abstract
BACKGROUND Among the three model cyanobacterial species that have been used for engineering a system for photosynthetic production of free fatty acids (FFAs), Synechococcus elongatus PCC7942 has been the least successful; the FFA-excreting mutants constructed from this strain could attain lower rates of FFA excretion and lower final FFA concentrations than the mutants constructed from Synechocystis sp. PCC6803 and Synechococcus sp. PCC7002. It has been suggested that S. elongatus PCC7942 cells suffer from toxicity of FFA, but the cause of the low productivity has remained to be determined. RESULTS By modulating the expression level of the acyl-acyl carrier protein thioesterase and raising the light intensity during cultivation, FFA secretion rates comparable to those obtained with the other cyanobacterial species were attained with an engineered Synechococcus elongatus mutant (dAS1T). The final FFA concentration in the external medium was also higher than previously reported for other S. elongatus mutants. However, about 85 % of the total FFA in the culture was found to remain in the cells, causing severe photoinhibition. Targeted inactivation of the wzt gene in dAS1T, which gene manipulation was previously shown to result in loss of the hydrophilic O-antigen layer on the cell surface, increased FFA secretion, alleviated photoinhibition, and lead to 50 and 45 % increase in the final cell density and the total amount of FFA in the culture (i.e., the sum of the cellular and extracellular FFA), respectively. The average rate of production of total FFA by the culture of the ∆wzt strain was 2.7 mg L(-1) h(-1), being five times higher than those reported for Synechocystis sp. PCC 6803 and comparable to the rates of triacylglycerol production in green algae. CONCLUSION Synechococcus elongatus PCC7942 has larger capacity of FFA production than Synechocystis sp. PCC6803 but accumulates most of the product in the cell because of the imbalance of the rates of FFA production and secretion. This causes severe photoinhibition and exerts adverse effects on cell growth and FFA productivity. Enhancement of FFA secretion would be required to fully exploiting the capacity of FFA production for the purpose of biofuel production.
Collapse
Affiliation(s)
- Akihiro Kato
- />Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
| | - Kazuhide Use
- />Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
| | - Nobuyuki Takatani
- />Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
- />Japan Science and Technology Agency, CREST, Tokyo, Japan
| | - Kazutaka Ikeda
- />Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0052 Japan
- />Japan Science and Technology Agency, CREST, Tokyo, Japan
- />Laboratory for Metabolomics, RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045 Japan
| | - Miyuki Matsuura
- />Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
| | - Kouji Kojima
- />Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
- />Japan Science and Technology Agency, CREST, Tokyo, Japan
| | - Makiko Aichi
- />Department of Biological Chemistry, Chubu University, Kasugai, 487-8501 Japan
- />Japan Science and Technology Agency, CREST, Tokyo, Japan
| | - Shin-ichi Maeda
- />Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
- />Japan Science and Technology Agency, CREST, Tokyo, Japan
| | - Tatsuo Omata
- />Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
- />Japan Science and Technology Agency, CREST, Tokyo, Japan
- />Laboratory of Molecular Plant Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo, Chikusa, Nagoya, 464-8601 Japan
| |
Collapse
|
46
|
Role of the Tet38 Efflux Pump in Staphylococcus aureus Internalization and Survival in Epithelial Cells. Infect Immun 2015; 83:4362-72. [PMID: 26324534 DOI: 10.1128/iai.00723-15] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 08/24/2015] [Indexed: 12/22/2022] Open
Abstract
We previously identified the protein Tet38 as a chromosomally encoded efflux pump of Staphylococcus aureus that confers resistance to tetracycline and certain unsaturated fatty acids. Tet38 also contributes to mouse skin colonization. In this study, we discovered a novel regulator of tet38, named tetracycline regulator 21 (TetR21), that bound specifically to the tet38 promoter and repressed pump expression. A ΔtetR21 mutant showed a 5-fold increase in tet38 transcripts and an 8-fold increase in resistance to tetracycline and fatty acids. The global regulator MgrA bound to the tetR21 promoter and indirectly repressed the expression of tet38. To further assess the full role of Tet38 in S. aureus adaptability, we tested its effect on host cell invasion using A549 (lung) and HMEC-1 (heart) cell lines. We used S. aureus RN6390, its Δtet38, ΔtetR21, and ΔmgrA mutants, and a Δtet38 ΔtetR21 double mutant. After 2 h of contact, the Δtet38 mutant was internalized in 6-fold-lower numbers than RN6390 in A549 and HMEC-1 cells, and the ΔtetR21 mutant was internalized in 2-fold-higher numbers than RN6390. A slight increase of 1.5-fold in internalization was found for the ΔmgrA mutant. The growth patterns of RN6390 and the ΔmgrA and ΔtetR21 mutants within A549 cells were similar, while no growth was observed for the Δtet38 mutant. These data indicate that the Tet38 efflux pump is regulated by TetR21 and contributes to the ability of S. aureus to internalize and replicate within epithelial cells.
Collapse
|