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Liberini E, Fan SH, Bayer AS, Beck C, Biboy J, François P, Gray J, Hipp K, Koch I, Peschel A, Sailer B, Vollmer D, Vollmer W, Götz F. Staphylococcus aureus Stress Response to Bicarbonate Depletion. Int J Mol Sci 2024; 25:9251. [PMID: 39273203 PMCID: PMC11394868 DOI: 10.3390/ijms25179251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2024] [Revised: 08/16/2024] [Accepted: 08/19/2024] [Indexed: 09/15/2024] Open
Abstract
Bicarbonate and CO2 are essential substrates for carboxylation reactions in bacterial central metabolism. In Staphylococcus aureus, the bicarbonate transporter, MpsABC (membrane potential-generating system) is the only carbon concentrating system. An mpsABC deletion mutant can hardly grow in ambient air. In this study, we investigated the changes that occur in S. aureus when it suffers from CO2/bicarbonate deficiency. Electron microscopy revealed that ΔmpsABC has a twofold thicker cell wall thickness compared to the parent strain. The mutant was also substantially inert to cell lysis induced by lysostaphin and the non-ionic surfactant Triton X-100. Mass spectrometry analysis of muropeptides revealed the incorporation of alanine into the pentaglycine interpeptide bridge, which explains the mutant's lysostaphin resistance. Flow cytometry analysis of wall teichoic acid (WTA) glycosylation patterns revealed a significantly lower α-glycosylated and higher ß-glycosylated WTA, explaining the mutant's increased resistance towards Triton X-100. Comparative transcriptome analysis showed altered gene expression profiles. Autolysin-encoding genes such as sceD, a lytic transglycosylase encoding gene, were upregulated, like in vancomycin-intermediate S. aureus mutants (VISA). Genes related to cell wall-anchored proteins, secreted proteins, transporters, and toxins were downregulated. Overall, we demonstrate that bicarbonate deficiency is a stress response that causes changes in cell wall composition and global gene expression resulting in increased resilience to cell wall lytic enzymes and detergents.
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Affiliation(s)
- Elisa Liberini
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076 Tübingen, Germany
| | - Sook-Ha Fan
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076 Tübingen, Germany
- The Lundquist Institute, Torrance, CA 90502, USA
| | - Arnold S Bayer
- The Lundquist Institute, Torrance, CA 90502, USA
- David Geffen School of Medicine at UCLA-University of California, Los Angeles, CA 90095, USA
| | - Christian Beck
- Department of Infection Biology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076 Tübingen, Germany
| | - Jacob Biboy
- Biosciences Institute, Centre for Bacterial Cell Biology, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Patrice François
- Genomic Research Laboratory, Division of Infectious Diseases, Faculty of Medicine, Geneva University Hospitals, 1205 Geneva, Switzerland
| | - Joe Gray
- Biosciences Institute, Centre for Bacterial Cell Biology, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Katharina Hipp
- Electron Microscopy Facility, Max-Planck-Institute for Biology, 72076 Tübingen, Germany
| | - Iris Koch
- Electron Microscopy Facility, Max-Planck-Institute for Biology, 72076 Tübingen, Germany
| | - Andreas Peschel
- Department of Infection Biology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076 Tübingen, Germany
- Excellence Cluster 2124 'Controlling Microbes to Fight Infections' (CMFI), University of Tübingen, 72076 Tübingen, Germany
| | - Brigitte Sailer
- Electron Microscopy Facility, Max-Planck-Institute for Biology, 72076 Tübingen, Germany
| | - Daniela Vollmer
- Biosciences Institute, Centre for Bacterial Cell Biology, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Waldemar Vollmer
- Biosciences Institute, Centre for Bacterial Cell Biology, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Friedrich Götz
- Microbial Genetics, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076 Tübingen, Germany
- Excellence Cluster 2124 'Controlling Microbes to Fight Infections' (CMFI), University of Tübingen, 72076 Tübingen, Germany
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Lai LY, Satishkumar N, Cardozo S, Hemmadi V, Marques LB, Huang L, Filipe SR, Pinho MG, Chambers HF, Chatterjee SS. Altered PBP4 and GdpP functions synergistically mediate MRSA-like high-level, broad-spectrum β-lactam resistance in Staphylococcus aureus. mBio 2024; 15:e0288923. [PMID: 38530033 PMCID: PMC11077961 DOI: 10.1128/mbio.02889-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 03/04/2024] [Indexed: 03/27/2024] Open
Abstract
Infections caused by Staphylococcus aureus are a leading cause of mortality worldwide. S. aureus infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are particularly difficult to treat due to their resistance to next-generation β-lactams (NGBs) such as methicillin, nafcillin, and oxacillin. Resistance to NGBs, which is alternatively known as broad-spectrum β-lactam resistance, is classically mediated by PBP2a, a penicillin-binding protein encoded by mecA (or mecC) in MRSA. Thus, presence of mec genes among S. aureus spp. serves as the predictor of resistance to NGBs and facilitates determination of the proper therapeutic strategy for a staphylococcal infection. Although far less appreciated, mecA-deficient S. aureus strains can also exhibit NGB resistance. These strains, which are collectively termed as methicillin-resistant lacking mec (MRLM), are currently being identified in increasing numbers among natural resistant isolates of S. aureus. The mechanism/s through which MRLMs produce resistance to NGBs remains unknown. In this study, we demonstrate that mutations that alter PBP4 and GdpP functions, which are often present among MRLMs, can synergistically mediate resistance to NGBs. Furthermore, our results unravel that this novel mechanism potentially enables MRLMs to produce resistance toward NGBs at levels comparable to those of MRSAs. Our study provides a fresh new perspective about alternative mechanisms of NGB resistance, challenging our current overall understanding of high-level, broad-spectrum β-lactam resistance in S. aureus. It thus suggests reconsideration of the current approach toward diagnosis and treatment of β-lactam-resistant S. aureus infections. IMPORTANCE In Staphylococcus aureus, high-level, broad-spectrum resistance to β-lactams such as methicillin, also referred to as methicillin resistance, is largely attributed to mecA. This study demonstrates that S. aureus strains that lack mecA but contain mutations that functionally alter PBP4 and GdpP can also mediate high-level, broad-spectrum resistance to β-lactams. Resistance brought about by the synergistic action of functionally altered PBP4 and GdpP was phenotypically comparable to that displayed by mecA, as seen by increased bacterial survival in the presence of β-lactams. An analysis of mutations detected in naturally isolated strains of S. aureus revealed that a significant proportion of them had similar pbp4 and GGDEF domain protein containing phosphodiesterase (gdpP) mutations, making this study clinically significant. This study not only identifies important players of non-classical mechanisms of β-lactam resistance but also indicates reconsideration of current clinical diagnosis and treatment protocols of S. aureus infections.
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Affiliation(s)
- Li-Yin Lai
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Nidhi Satishkumar
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Sasha Cardozo
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Vijay Hemmadi
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Leonor B. Marques
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Liusheng Huang
- Department of Clinical Pharmacy, Drug Research Unit, University of California, San Francisco, California, USA
| | - Sergio R. Filipe
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Mariana G. Pinho
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Henry F. Chambers
- Division of Infectious Diseases, School of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Som S. Chatterjee
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland Baltimore, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
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3
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Kwan JMC, Liang Y, Ng EWL, Sviriaeva E, Li C, Zhao Y, Zhang XL, Liu XW, Wong SH, Qiao Y. In silico MS/MS prediction for peptidoglycan profiling uncovers novel anti-inflammatory peptidoglycan fragments of the gut microbiota. Chem Sci 2024; 15:1846-1859. [PMID: 38303944 PMCID: PMC10829024 DOI: 10.1039/d3sc05819k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/19/2023] [Indexed: 02/03/2024] Open
Abstract
Peptidoglycan is an essential exoskeletal polymer across all bacteria. Gut microbiota-derived peptidoglycan fragments (PGNs) are increasingly recognized as key effector molecules that impact host biology. However, the current peptidoglycan analysis workflow relies on laborious manual identification from tandem mass spectrometry (MS/MS) data, impeding the discovery of novel bioactive PGNs in the gut microbiota. In this work, we built a computational tool PGN_MS2 that reliably simulates MS/MS spectra of PGNs and integrated it into the user-defined MS library of in silico PGN search space, facilitating automated PGN identification. Empowered by PGN_MS2, we comprehensively profiled gut bacterial peptidoglycan composition. Strikingly, the probiotic Bifidobacterium spp. manifests an abundant amount of the 1,6-anhydro-MurNAc moiety that is distinct from Gram-positive bacteria. In addition to biochemical characterization of three putative lytic transglycosylases (LTs) that are responsible for anhydro-PGN production in Bifidobacterium, we established that these 1,6-anhydro-PGNs exhibit potent anti-inflammatory activity in vitro, offering novel insights into Bifidobacterium-derived PGNs as molecular signals in gut microbiota-host crosstalk.
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Affiliation(s)
- Jeric Mun Chung Kwan
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University 11 Mandalay Road 308232 Singapore
| | - Yaquan Liang
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
| | - Evan Wei Long Ng
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
| | - Ekaterina Sviriaeva
- Lee Kong Chian School of Medicine, Nanyang Technological University 11 Mandalay Road 308232 Singapore
| | - Chenyu Li
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
| | - Yilin Zhao
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
| | - Xiao-Lin Zhang
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
| | - Xue-Wei Liu
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
| | - Sunny H Wong
- Lee Kong Chian School of Medicine, Nanyang Technological University 11 Mandalay Road 308232 Singapore
| | - Yuan Qiao
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
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Panda S, Jayasinghe YP, Shinde DD, Bueno E, Stastny A, Bertrand BP, Chaudhari SS, Kielian T, Cava F, Ronning DR, Thomas VC. Staphylococcus aureus counters organic acid anion-mediated inhibition of peptidoglycan cross-linking through robust alanine racemase activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.15.575639. [PMID: 38293037 PMCID: PMC10827132 DOI: 10.1101/2024.01.15.575639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Weak organic acids are commonly found in host niches colonized by bacteria, and they can inhibit bacterial growth as the environment becomes acidic. This inhibition is often attributed to the toxicity resulting from the accumulation of high concentrations of organic anions in the cytosol, which disrupts cellular homeostasis. However, the precise cellular targets that organic anions poison and the mechanisms used to counter organic anion intoxication in bacteria have not been elucidated. Here, we utilize acetic acid, a weak organic acid abundantly found in the gut to investigate its impact on the growth of Staphylococcus aureus. We demonstrate that acetate anions bind to and inhibit d-alanyl-d-alanine ligase (Ddl) activity in S. aureus. Ddl inhibition reduces intracellular d-alanyl-d-alanine (d-Ala-d-Ala) levels, compromising staphylococcal peptidoglycan cross-linking and cell wall integrity. To overcome the effects of acetate-mediated Ddl inhibition, S. aureus maintains a high intracellular d-Ala pool through alanine racemase (Alr1) activity and additionally limits the flux of d-Ala to d-glutamate by controlling d-alanine aminotransferase (Dat) activity. Surprisingly, the modus operandi of acetate intoxication in S. aureus is common to multiple biologically relevant weak organic acids indicating that Ddl is a conserved target of small organic anions. These findings suggest that S. aureus may have evolved to maintain high intracellular d-Ala concentrations, partly to counter organic anion intoxication.
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Affiliation(s)
- Sasmita Panda
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
| | - Yahani P Jayasinghe
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Dhananjay D Shinde
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
| | - Emilio Bueno
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Center for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, Umea SE-90187, Sweden
| | - Amanda Stastny
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
| | - Blake P Bertrand
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
| | - Sujata S Chaudhari
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
| | - Tammy Kielian
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Center for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, Umea SE-90187, Sweden
| | - Donald R Ronning
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Vinai C Thomas
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
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5
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Ambade SS, Gupta VK, Bhole RP, Khedekar PB, Chikhale RV. A Review on Five and Six-Membered Heterocyclic Compounds Targeting the Penicillin-Binding Protein 2 (PBP2A) of Methicillin-Resistant Staphylococcus aureus (MRSA). Molecules 2023; 28:7008. [PMID: 37894491 PMCID: PMC10609489 DOI: 10.3390/molecules28207008] [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: 09/08/2023] [Revised: 10/05/2023] [Accepted: 10/05/2023] [Indexed: 10/29/2023] Open
Abstract
Staphylococcus aureus is a common human pathogen. Methicillin-resistant Staphylococcus aureus (MRSA) infections pose significant and challenging therapeutic difficulties. MRSA often acquires the non-native gene PBP2a, which results in reduced susceptibility to β-lactam antibiotics, thus conferring resistance. PBP2a has a lower affinity for methicillin, allowing bacteria to maintain peptidoglycan biosynthesis, a core component of the bacterial cell wall. Consequently, even in the presence of methicillin or other antibiotics, bacteria can develop resistance. Due to genes responsible for resistance, S. aureus becomes MRSA. The fundamental premise of this resistance mechanism is well-understood. Given the therapeutic concerns posed by resistant microorganisms, there is a legitimate demand for novel antibiotics. This review primarily focuses on PBP2a scaffolds and the various screening approaches used to identify PBP2a inhibitors. The following classes of compounds and their biological activities are discussed: Penicillin, Cephalosporins, Pyrazole-Benzimidazole-based derivatives, Oxadiazole-containing derivatives, non-β-lactam allosteric inhibitors, 4-(3H)-Quinazolinones, Pyrrolylated chalcone, Bis-2-Oxoazetidinyl macrocycles (β-lactam antibiotics with 1,3-Bridges), Macrocycle-embedded β-lactams as novel inhibitors, Pyridine-Coupled Pyrimidinones, novel Naphthalimide corbelled aminothiazoximes, non-covalent inhibitors, Investigational-β-lactam antibiotics, Carbapenem, novel Benzoxazole derivatives, Pyrazolylpyridine analogues, and other miscellaneous classes of scaffolds for PBP2a. Additionally, we discuss the penicillin-binding protein, a crucial target in the MRSA cell wall. Various aspects of PBP2a, bacterial cell walls, peptidoglycans, different crystal structures of PBP2a, synthetic routes for PBP2a inhibitors, and future perspectives on MRSA inhibitors are also explored.
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Affiliation(s)
- Shraddha S. Ambade
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440033, MH, India (P.B.K.)
| | - Vivek Kumar Gupta
- Department of Biochemistry, National JALMA Institute for Leprosy & Other Mycobacterial Diseases (ICMR), Agra 282004, UP, India
| | - Ritesh P. Bhole
- Dr. D. Y. Patil Institute of Pharmaceutical Sciences and Research, Pimpri, Pune 411018, MH, India
- Dr. D. Y. Patil Dental College and Hospital, Dr. D. Y. Patil Vidyapeeth, Pimpri, Pune 411018, MH, India
| | - Pramod B. Khedekar
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440033, MH, India (P.B.K.)
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Gómez-Arrebola C, Hernandez SB, Culp EJ, Wright GD, Solano C, Cava F, Lasa I. Staphylococcus aureus susceptibility to complestatin and corbomycin depends on the VraSR two-component system. Microbiol Spectr 2023; 11:e0037023. [PMID: 37646518 PMCID: PMC10581084 DOI: 10.1128/spectrum.00370-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 06/30/2023] [Indexed: 09/01/2023] Open
Abstract
The overuse of antibiotics in humans and livestock has driven the emergence and spread of antimicrobial resistance and has therefore prompted research on the discovery of novel antibiotics. Complestatin (Cm) and corbomycin (Cb) are glycopeptide antibiotics with an unprecedented mechanism of action that is active even against methicillin-resistant and daptomycin-resistant Staphylococcus aureus. They bind to peptidoglycan and block the activity of peptidoglycan hydrolases required for remodeling the cell wall during growth. Bacterial signaling through two-component transduction systems (TCSs) has been associated with the development of S. aureus antimicrobial resistance. However, the role of TCSs in S. aureus susceptibility to Cm and Cb has not been previously addressed. In this study, we determined that, among all 16 S. aureus TCSs, VraSR is the only one controlling the susceptibility to Cm and Cb. Deletion of vraSR increased bacterial susceptibility to both antibiotics. Epistasis analysis with members of the vraSR regulon revealed that deletion of spdC, which encodes a membrane protein that scaffolds SagB for cleavage of peptidoglycan strands to achieve physiological length, in the vraSR mutant restored Cm and Cb susceptibility to wild-type levels. Moreover, deletion of either spdC or sagB in the wild-type strain increased resistance to both antibiotics. Further analyses revealed a significant rise in the relative amount of peptidoglycan and its total degree of cross-linkage in ΔspdC and ΔsagB mutants compared to the wild-type strain, suggesting that these changes in the cell wall provide resistance to the damaging effect of Cm and Cb. IMPORTANCE Although Staphylococcus aureus is a common colonizer of the skin and digestive tract of humans and many animals, it is also a versatile pathogen responsible for causing a wide variety and number of infections. Treatment of these infections requires the bacteria to be constantly exposed to antibiotic treatment, which facilitates the selection of antibiotic-resistant strains. The development of new antibiotics is, therefore, urgently needed. In this paper, we investigated the role of the sensory system of S. aureus in susceptibility to two new antibiotics: corbomycin and complestatin. The results shed light on the cell-wall synthesis processes that are affected by the presence of the antibiotic and the sensory system responsible for coordinating their activity.
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Affiliation(s)
- Carmen Gómez-Arrebola
- Laboratory of Microbial Pathogenesis, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - Sara B. Hernandez
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Elizabeth J. Culp
- Department of Biochemistry and Biomedical Sciences, M. G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Gerard D. Wright
- Department of Biochemistry and Biomedical Sciences, M. G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Cristina Solano
- Laboratory of Microbial Pathogenesis, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - Felipe Cava
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Iñigo Lasa
- Laboratory of Microbial Pathogenesis, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
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Kim H, Seo J. A Novel Strategy to Identify Endolysins with Lytic Activity against Methicillin-Resistant Staphylococcus aureus. Int J Mol Sci 2023; 24:ijms24065772. [PMID: 36982851 PMCID: PMC10059956 DOI: 10.3390/ijms24065772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/10/2023] [Accepted: 03/15/2023] [Indexed: 03/22/2023] Open
Abstract
The increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the dairy industry has become a fundamental concern. Endolysins are bacteriophage-derived peptidoglycan hydrolases that induce the rapid lysis of host bacteria. Herein, we evaluated the lytic activity of endolysin candidates against S. aureus and MRSA. To identify endolysins, we used a bioinformatical strategy with the following steps: (1) retrieval of genetic information, (2) annotation, (3) selection of MRSA, (4) selection of endolysin candidates, and (5) evaluation of protein solubility. We then characterized the endolysin candidates under various conditions. Approximately 67% of S. aureus was detected as MRSA, and 114 putative endolysins were found. These 114 putative endolysins were divided into three groups based on their combinations of conserved domains. Considering protein solubility, we selected putative endolysins 117 and 177. Putative endolysin 117 was the only successfully overexpressed endolysin, and it was renamed LyJH1892. LyJH1892 showed potent lytic activity against both methicillin-susceptible S. aureus and MRSA and showed broad lytic activity against coagulase-negative staphylococci. In conclusion, this study demonstrates a rapid strategy for the development of endolysin against MRSA. This strategy could also be used to combat other antibiotic-resistant bacteria.
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8
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Gram-Positive Bacteria Cell Wall Peptidoglycan Polymers Activate Human Dendritic Cells to Produce IL-23 and IL-1β and Promote T H17 Cell Differentiation. Microorganisms 2023; 11:microorganisms11010173. [PMID: 36677464 PMCID: PMC9867153 DOI: 10.3390/microorganisms11010173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/22/2022] [Accepted: 01/04/2023] [Indexed: 01/12/2023] Open
Abstract
Gram-positive bacterial infections are a major cause of organ failure and mortality in sepsis. Cell wall peptidoglycan (PGN) is shed during bacterial replication, and Bacillus anthracis PGN promotes a sepsis-like pathology in baboons. Herein, we determined the ability of polymeric Bacillus anthracis PGN free from TLR ligands to shape human dendritic cell (DC) responses that are important for the initiation of T cell immunity. Monocyte-derived DCs from healthy donors were incubated with PGN polymers isolated from Bacillus anthracis and Staphylococcus aureus. PGN activated the human DCs, as judged by the increased expression of surface HLA-DR, CD83, the T cell costimulatory molecules CD40 and CD86, and the chemokine receptor CCR7. PGN elicited the DC production of IL-23, IL-6, and IL-1β but not IL-12p70. The PGN-stimulated DCs induced the differentiation of naïve allogeneic CD4+ T cells into T helper (TH) cells producing IL-17 and IL-21. Notably, the DCs from a subset of donors did not produce significant levels of IL-23 and IL-1β upon PGN stimulation, suggesting that common polymorphisms in immune response genes regulate the PGN response. In sum, purified PGN is a highly stimulatory cell wall component that activates human DCs to secrete proinflammatory cytokines and promote the differentiation of TH17 cells that are important for neutrophil recruitment in extracellular bacterial infections.
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9
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Zha J, Li J, Su Z, Akimbekov N, Wu X. Lysostaphin: Engineering and Potentiation toward Better Applications. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:11441-11457. [PMID: 36082619 DOI: 10.1021/acs.jafc.2c03459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Lysostaphin is a potent bacteriolytic enzyme with endopeptidase activity against the common pathogen Staphylococcus aureus. By digesting the pentaglycine crossbridge in the cell wall peptidoglycan of S. aureus including the methicillin-resistant strains, lysostaphin initiates rapid lysis of planktonic and sessile cells (biofilms) and has great potential for use in agriculture, food industries, and pharmaceutical industries. In the past few decades, there have been tremendous efforts in potentiating lysostaphin for better applications in these fields, including engineering of the enzyme for higher potency and lower immunogenicity with longer-lasting effects, formulation and immobilization of the enzyme for higher stability and better durability, and recombinant expression for low-cost industrial production and in situ biocontrol. These achievements are extensively reviewed in this article focusing on applications in disease control, food preservation, surface decontamination, and pathogen detection. In addition, some basic properties of lysostaphin that have been controversial and only elucidated recently are summarized, including the substrate-binding properties, the number of zinc-binding sites, the substrate range, and the cleavage site in the pentaglycine crossbridge. Resistance to lysostaphin is also highlighted with a focus on various mechanisms. This article is concluded with a discussion on the limitations and future perspectives for the actual applications of lysostaphin.
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Affiliation(s)
- Jian Zha
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Jingyuan Li
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Zheng Su
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Nuraly Akimbekov
- Department of Biotechnology, Al-Farabi Kazakh National University, Almaty 050040, Kazakhstan
| | - Xia Wu
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
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10
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Rimal B, Senzani S, Ealand C, Lamichhane G, Kana B, Kim SJ. Peptidoglycan compositional analysis of Mycobacterium smegmatis using high-resolution LC-MS. Sci Rep 2022; 12:11061. [PMID: 35773428 PMCID: PMC9247062 DOI: 10.1038/s41598-022-15324-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/22/2022] [Indexed: 11/21/2022] Open
Abstract
Peptidoglycan (PG) is the exoskeleton of bacterial cells and is required for their viability, growth, and cell division. Unlike most bacteria, mycobacteria possess an atypical PG characterized by a high degree of unique linkages and chemical modifications which most likely serve as important determinants of virulence and pathogenesis in mycobacterial diseases. Despite this important role, the chemical composition and molecular architecture of mycobacterial PG have yet to be fully determined. Here we determined the chemical composition of PG from Mycobacterium smegmatis using high-resolution liquid chromatography-mass spectrometry. Purified cell walls from the stationary phase were digested with mutanolysin and compositional analysis was performed on 130 muropeptide ions that were identified using an in silico PG library. The relative abundance for each muropeptide ion was measured by integrating the extracted-ion chromatogram. The percentage of crosslink per PG subunit was measured at 45%. While both 3→3 and 4→3 transpeptide cross-linkages were found in PG dimers, a high abundance of 3→3 linkages was found associated with the trimers. Approximately 43% of disaccharides in the PG of M. smegmatis showed modifications by acetylation or deacetylation. A significant number of PG trimers are found with a loss of 41.00 amu that is consistent with N-deacetylation, whereas the dimers show a gain of 42.01 amu corresponding to O-acetylation of the PG disaccharides. This suggests a possible role of PG acetylation in the regulation of cell wall homeostasis in M. smegmatis. Collectively, these data report important novel insights into the ultrastructure of mycobacterial PG.
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Affiliation(s)
- Binayak Rimal
- Institute of Biomedical Studies, Baylor University, Waco, TX, 76798, USA.,Division of Infectious Diseases, School of Medicine, Johns Hopkins University, Baltimore, MD, 21287, USA
| | - Sibusiso Senzani
- National Health Laboratory Service, Faculty of Health Sciences, DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, University of the Witwatersrand, Johannesburg, 2001, South Africa
| | - Christopher Ealand
- National Health Laboratory Service, Faculty of Health Sciences, DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, University of the Witwatersrand, Johannesburg, 2001, South Africa
| | - Gyanu Lamichhane
- Division of Infectious Diseases, School of Medicine, Johns Hopkins University, Baltimore, MD, 21287, USA
| | - Bavesh Kana
- National Health Laboratory Service, Faculty of Health Sciences, DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, University of the Witwatersrand, Johannesburg, 2001, South Africa.
| | - Sung Joon Kim
- Department of Chemistry, Howard University, Chemistry Building, 525 College Street, Washington, DC, 20059, USA.
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11
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Pseudomonas aeruginosa Alters Peptidoglycan Composition under Nutrient Conditions Resembling Cystic Fibrosis Lung Infections. mSystems 2022; 7:e0015622. [PMID: 35545925 PMCID: PMC9239049 DOI: 10.1128/msystems.00156-22] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Epidemic strains of Pseudomonas aeruginosa are highly virulent opportunistic pathogens with increased transmissibility and enhanced antimicrobial resistance. Understanding the cellular mechanisms behind this heightened virulence and resistance is critical. Peptidoglycan (PG) is an integral component of P. aeruginosa cells that is essential to its survival and a target for antimicrobials. Here, we examined the global PG composition of two P. aeruginosa epidemic strains, LESB58 and LESlike1, and compared them to the common laboratory strains PAO1 and PA14. We also examined changes in PG composition when the strains were cultured under nutrient conditions that resembled cystic fibrosis lung infections. We identified 448 unique muropeptides and provide the first evidence for stem peptides modified with O-methylation, meso-diaminopimelic acid (mDAP) deamination, and novel substitutions of mDAP residues within P. aeruginosa PG. Our results also present the first evidence for both d,l- and l,d-endopeptidase activity on the PG sacculus of a Gram-negative organism. The PG composition of the epidemic strains varied significantly when grown under conditions resembling cystic fibrosis (CF) lung infections, showing increases in O-methylated stem peptides and decreases in l,d-endopeptidase activity as well as an increased abundance of de-N-acetylated sugars and l,d-transpeptidase activity, which are related to bacterial virulence and antibiotic resistance, respectively. We also identified strain-specific changes where LESlike1 increased the addition of unique amino acids to the terminus of the stem peptide and LESB58 increased amidase activity. Overall, this study demonstrates that P. aeruginosa PG composition is primarily influenced by nutrient conditions that mimic the CF lung; however, inherent strain-to-strain differences also exist. IMPORTANCE Using peptidoglycomics to examine the global composition of the peptidoglycan (PG) allows insights into the enzymatic activity that functions on this important biopolymer. Changes within the PG structure have implications for numerous physiological processes, including virulence and antimicrobial resistance. The identification of highly unique PG modifications illustrates the complexity of this biopolymer in Pseudomonas aeruginosa. Analyzing the PG composition of clinical P. aeruginosa epidemic strains provides insights into the increased virulence and antimicrobial resistance of these difficult-to-eradicate infections.
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12
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Wang F, Xiao Y, Lu Y, Deng ZY, Deng XY, Lin LB. Bacteriophage Lytic Enzyme P9ly as an Alternative Antibacterial Agent Against Antibiotic-Resistant Shigella dysenteriae and Staphylococcus aureus. Front Microbiol 2022; 13:821989. [PMID: 35237249 PMCID: PMC8882861 DOI: 10.3389/fmicb.2022.821989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/19/2022] [Indexed: 11/24/2022] Open
Abstract
Developing new strategies to replace or supplement antibiotics to combat bacterial infection is a pressing task in the field of microbiological research. In this study, we report a lytic enzyme named P9ly deriving from the bacteriophage PSD9 that could infect multidrug-resistant Shigella. This enzyme was identified through whole-genome sequencing of PSD9. The results show that P9ly contains a conserved T4-like_lys domain and belongs to the phage lysozyme family. Recombinant P9ly obtained from protein purification presented biological activity and could digest bacterial cell walls (CW), resulting in the destruction of cell structure and leakage of intracellular components. Furthermore, P9ly exhibited bacteriolytic and bactericidal activity on different strains, especially multidrug-resistant Gram-negative Shigella dysenteriae and Gram-positive Staphylococcus aureus. Additionally, combined use of P9ly with ceftriaxone sodium (CRO) could decrease necessary dose of the antibiotic used and improve the antibacterial effect. In summary, under the current backdrop of extensive antibiotic usage and the continuous emergence of bacterial resistance, this study provides an insight into developing bacteriophage-based antibacterial agents against both Gram-negative and Gram-positive pathogens.
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Affiliation(s)
- Feng Wang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Yao Xiao
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Yao Lu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Zheng-Yu Deng
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Xian-Yu Deng
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Lian-Bing Lin
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
- Engineering Research Center for Replacement Technology of Feed Antibiotics of Yunnan College, Kunming, China
- *Correspondence: Lian-Bing Lin,
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13
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Accumulation of Succinyl Coenzyme A Perturbs the Methicillin-Resistant Staphylococcus aureus (MRSA) Succinylome and Is Associated with Increased Susceptibility to Beta-Lactam Antibiotics. mBio 2021; 12:e0053021. [PMID: 34182779 PMCID: PMC8437408 DOI: 10.1128/mbio.00530-21] [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] [Indexed: 01/05/2023] Open
Abstract
Penicillin binding protein 2a (PBP2a)-dependent resistance to β-lactam antibiotics in methicillin-resistant Staphylococcus aureus (MRSA) is regulated by the activity of the tricarboxylic acid (TCA) cycle via a poorly understood mechanism. We report that mutations in sucC and sucD, but not other TCA cycle enzymes, negatively impact β-lactam resistance without changing PBP2a expression. Increased intracellular levels of succinyl coenzyme A (succinyl-CoA) in the sucC mutant significantly perturbed lysine succinylation in the MRSA proteome. Suppressor mutations in sucA or sucB, responsible for succinyl-CoA biosynthesis, reversed sucC mutant phenotypes. The major autolysin (Atl) was the most succinylated protein in the proteome, and increased Atl succinylation in the sucC mutant was associated with loss of autolytic activity. Although PBP2a and PBP2 were also among the most succinylated proteins in the MRSA proteome, peptidoglycan architecture and cross-linking were unchanged in the sucC mutant. These data reveal that perturbation of the MRSA succinylome impacts two interconnected cell wall phenotypes, leading to repression of autolytic activity and increased susceptibility to β-lactam antibiotics.
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14
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Lade H, Kim JS. Bacterial Targets of Antibiotics in Methicillin-Resistant Staphylococcus aureus. Antibiotics (Basel) 2021; 10:398. [PMID: 33917043 PMCID: PMC8067735 DOI: 10.3390/antibiotics10040398] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 12/17/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most prevalent bacterial pathogens and continues to be a leading cause of morbidity and mortality worldwide. MRSA is a commensal bacterium in humans and is transmitted in both community and healthcare settings. Successful treatment remains a challenge, and a search for new targets of antibiotics is required to ensure that MRSA infections can be effectively treated in the future. Most antibiotics in clinical use selectively target one or more biochemical processes essential for S. aureus viability, e.g., cell wall synthesis, protein synthesis (translation), DNA replication, RNA synthesis (transcription), or metabolic processes, such as folic acid synthesis. In this review, we briefly describe the mechanism of action of antibiotics from different classes and discuss insights into the well-established primary targets in S. aureus. Further, several components of bacterial cellular processes, such as teichoic acid, aminoacyl-tRNA synthetases, the lipid II cycle, auxiliary factors of β-lactam resistance, two-component systems, and the accessory gene regulator quorum sensing system, are discussed as promising targets for novel antibiotics. A greater molecular understanding of the bacterial targets of antibiotics has the potential to reveal novel therapeutic strategies or identify agents against antibiotic-resistant pathogens.
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Affiliation(s)
| | - Jae-Seok Kim
- Department of Laboratory Medicine, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul 05355, Korea;
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15
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Staphylococcus aureus cell wall structure and dynamics during host-pathogen interaction. PLoS Pathog 2021; 17:e1009468. [PMID: 33788901 PMCID: PMC8041196 DOI: 10.1371/journal.ppat.1009468] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 04/12/2021] [Accepted: 03/12/2021] [Indexed: 01/09/2023] Open
Abstract
Peptidoglycan is the major structural component of the Staphylococcus aureus cell wall, in which it maintains cellular integrity, is the interface with the host, and its synthesis is targeted by some of the most crucial antibiotics developed. Despite this importance, and the wealth of data from in vitro studies, we do not understand the structure and dynamics of peptidoglycan during infection. In this study we have developed methods to harvest bacteria from an active infection in order to purify cell walls for biochemical analysis ex vivo. Isolated ex vivo bacterial cells are smaller than those actively growing in vitro, with thickened cell walls and reduced peptidoglycan crosslinking, similar to that of stationary phase cells. These features suggested a role for specific peptidoglycan homeostatic mechanisms in disease. As S. aureus missing penicillin binding protein 4 (PBP4) has reduced peptidoglycan crosslinking in vitro its role during infection was established. Loss of PBP4 resulted in an increased recovery of S. aureus from the livers of infected mice, which coincided with enhanced fitness within murine and human macrophages. Thicker cell walls correlate with reduced activity of peptidoglycan hydrolases. S. aureus has a family of 4 putative glucosaminidases, that are collectively crucial for growth. Loss of the major enzyme SagB, led to attenuation during murine infection and reduced survival in human macrophages. However, loss of the other three enzymes Atl, SagA and ScaH resulted in clustering dependent attenuation, in a zebrafish embryo, but not a murine, model of infection. A combination of pbp4 and sagB deficiencies resulted in a restoration of parental virulence. Our results, demonstrate the importance of appropriate cell wall structure and dynamics during pathogenesis, providing new insight to the mechanisms of disease. The prevalence of methicillin resistant Staphylococcus aureus (MRSA) in both hospitals and the wider community places a huge weight on healthcare providers. To discover new control regimes, it is therefore important to understand how the pathogen behaves within the relevant environment of the host. This is often hampered by the ability to obtain sufficient ex vivo pathogen samples for study. We have developed a method to isolate S. aureus from the infected host to be able to analyse cellular morphology and structure. S. aureus, isolated from an infected kidney abscess are smaller in size, with thicker cell walls than exponentially growing cells in vitro. Their cell wall peptidoglycan also is less crosslinked. These features suggested the role of components controlling cell wall homeostasis as being important for infections. We tested the role of PBP4, known to increase cell wall crosslinking and found a pbp4 mutant to have increased survival in macrophages and fitness within the murine host. Conversely the peptidoglycan hydrolase SagB, whose loss results in thinner cell walls was attenuated in the murine systemic model of infection, with concomitant loss of fitness within macrophages. Our study reveals an important adaptation to the host environment and the role of those components involved in cell wall homeostasis in vivo.
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16
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Eld HMS, Nielsen EM, Johnsen PR, Marengo M, Kamper IW, Frederiksen L, Bonomi F, Frees D, Iametti S, Frøkiær H. Cefoxitin treatment of MRSA leads to a shift in the IL-12/IL-23 production pattern in dendritic cells by a mechanism involving changes in the MAPK signaling. Mol Immunol 2021; 134:1-12. [PMID: 33676343 DOI: 10.1016/j.molimm.2021.02.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 02/11/2021] [Accepted: 02/23/2021] [Indexed: 12/25/2022]
Abstract
Methicillin resistant Staphylococcus aureus (MRSA) constitute a serious health care problem worldwide. This study addresses the effect of β-lactam treatment on the ability of clinically relevant MRSA strains to induce IL-12 and IL-23. MRSA strains induced a dose-dependent IL-12 response in murine bone-marrow-derived dendritic cells that was dependent on endocytosis and acidic degradation. Facilitated induction of IL-12 (but not of IL-23) called for activation of the MAP kinase JNK, and was suppressed by p38. Compromised peptidoglycan structure in cefoxitin-treated bacteria - as denoted by increased sensitivity to mutanolysin -caused a shift from IL-12 towards IL-23. Moreover, cefoxitin treatment of MRSA led to a p38 MAPK-dependent early up-regulation of Dual Specificity Phosphatase (DUSP)-1. Compared to common MRSA, characteristics associated with a persister phenotype increased intracellular survival and upon cefoxitin treatment, the peptidoglycan was not equally compromised and the cytokine induction still required phagosomal acidification. Together, these data demonstrate that β-lactam treatment changes the MRSA-induced IL-12/IL-23 pattern determined by the activation of JNK and p38. We suggest that accelerated endosomal degradation of the peptidoglycan in cefoxitin-treated MRSA leads to an early expression of DUSP-1 and accordingly, a reduction in the IL-12/IL-23 ratio in dendritic cells. This may influence the clearance of S. aureus.
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Affiliation(s)
- Helene M S Eld
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emilie M Nielsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Peter R Johnsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mauro Marengo
- Department of Food, Environmental and Nutritional Science, Università degli Studi di Milano, Milan, Italy
| | - Ida W Kamper
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lise Frederiksen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Francesco Bonomi
- Department of Food, Environmental and Nutritional Science, Università degli Studi di Milano, Milan, Italy
| | - Dorte Frees
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stefania Iametti
- Department of Food, Environmental and Nutritional Science, Università degli Studi di Milano, Milan, Italy
| | - Hanne Frøkiær
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark.
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17
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Delvaux C, Dauvin M, Boulanger M, Quinton L, Mengin-Lecreulx D, Joris B, Pauw ED, Far J. Use of Capillary Zone Electrophoresis Coupled to Electrospray Mass Spectrometry for the Detection and Absolute Quantitation of Peptidoglycan-Derived Peptides in Bacterial Cytoplasmic Extracts. Anal Chem 2021; 93:2342-2350. [PMID: 33470796 DOI: 10.1021/acs.analchem.0c04218] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peptidoglycan (PGN) is an essential structure found in the bacterial cell wall. During the bacterial life cycle, PGN continuously undergoes biosynthesis and degradation to ensure bacterial growth and division. The resulting PGN fragments (muropeptides and peptides), which are generated by the bacterial autolytic system, are usually transported into the cytoplasm to be recycled. On the other hand, PGN fragments can act as messenger molecules involved in the bacterial cell wall stress response as in the case of β-lactamase induction in the presence of β-lactam antibiotic or in triggering mammalian innate immune response. During their cellular life, bacteria modulate their PGN degradation by their autolytic system or their recognition by the mammalian innate immune system by chemically modifying their PGN. Among these modifications, the amidation of the ε-carboxyl group of meso-diaminopimelic acid present in the PGN peptide chain is frequently observed. Currently, the detection and quantitation of PGN-derived peptides is still challenging because of the difficulty in separating these highly hydrophilic molecules by RP-HPLC as these compounds are eluted closely after the column void volume or coeluted in many cases. Here, we report the use of capillary zone electrophoresis coupled via an electrospray-based CE-MS interface to high-resolution mass spectrometry for the quantitation of three PGN peptides of interest and their amidated derivatives in bacterial cytoplasmic extracts. The absolute quantitation of the tripeptide based on the [13C,15N] isotopically labeled standard was also performed in crude cytoplasmic extracts of bacteria grown in the presence or absence of a β-lactam antibiotic (cephalosporin C). Despite the high complexity of the samples, the repeatability of the CZE-MS quantitation results was excellent, with relative standard deviations close to 1%. The global reproducibility of the method including biological handling was better than 20%.
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Affiliation(s)
- Cédric Delvaux
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier Agora, University of Liège, Allée du Six Août 11, B-4000 Liège, Belgium
| | - Marjorie Dauvin
- Centre for Protein Engineering, InBioS Research Unit, Quartier Agora, University of Liège, Allée du Six Août 13, B-4000 Liège, Belgium
| | - Madeleine Boulanger
- Centre for Protein Engineering, InBioS Research Unit, Quartier Agora, University of Liège, Allée du Six Août 13, B-4000 Liège, Belgium
| | - Loïc Quinton
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier Agora, University of Liège, Allée du Six Août 11, B-4000 Liège, Belgium
| | - Dominique Mengin-Lecreulx
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Bernard Joris
- Centre for Protein Engineering, InBioS Research Unit, Quartier Agora, University of Liège, Allée du Six Août 13, B-4000 Liège, Belgium
| | - Edwin De Pauw
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier Agora, University of Liège, Allée du Six Août 11, B-4000 Liège, Belgium
| | - Johann Far
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier Agora, University of Liège, Allée du Six Août 11, B-4000 Liège, Belgium
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18
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EslB Is Required for Cell Wall Biosynthesis and Modification in Listeria monocytogenes. J Bacteriol 2021; 203:JB.00553-20. [PMID: 33229460 PMCID: PMC7847544 DOI: 10.1128/jb.00553-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 11/16/2020] [Indexed: 12/13/2022] Open
Abstract
The ABC transporter EslABC is associated with the intrinsic lysozyme resistance of Listeria monocytogenes. However, the exact role of the transporter in this process and in the physiology of L. monocytogenes is unknown. Lysozyme is an important component of the innate immune system. It functions by hydrolyzing the peptidoglycan (PG) layer of bacteria. The human pathogen Listeria monocytogenes is intrinsically lysozyme resistant. The peptidoglycan N-deacetylase PgdA and O-acetyltransferase OatA are two known factors contributing to its lysozyme resistance. Furthermore, it was shown that the absence of components of an ABC transporter, referred to here as EslABC, leads to reduced lysozyme resistance. How its activity is linked to lysozyme resistance is still unknown. To investigate this further, a strain with a deletion in eslB, coding for a membrane component of the ABC transporter, was constructed in L. monocytogenes strain 10403S. The eslB mutant showed a 40-fold reduction in the MIC to lysozyme. Analysis of the PG structure revealed that the eslB mutant produced PG with reduced levels of O-acetylation. Using growth and autolysis assays, we showed that the absence of EslB manifests in a growth defect in media containing high concentrations of sugars and increased endogenous cell lysis. A thinner PG layer produced by the eslB mutant under these growth conditions might explain these phenotypes. Furthermore, the eslB mutant had a noticeable cell division defect and formed elongated cells. Microscopy analysis revealed that an early cell division protein still localized in the eslB mutant, indicating that a downstream process is perturbed. Based on our results, we hypothesize that EslB affects the biosynthesis and modification of the cell wall in L. monocytogenes and is thus important for the maintenance of cell wall integrity. IMPORTANCE The ABC transporter EslABC is associated with the intrinsic lysozyme resistance of Listeria monocytogenes. However, the exact role of the transporter in this process and in the physiology of L. monocytogenes is unknown. Using different assays to characterize an eslB deletion strain, we found that the absence of EslB affects not only lysozyme resistance but also endogenous cell lysis, cell wall biosynthesis, cell division, and the ability of the bacterium to grow in media containing high concentrations of sugars. Our results indicate that EslB is, by means of a yet-unknown mechanism, an important determinant for cell wall integrity in L. monocytogenes.
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19
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Mikkelsen K, Sirisarn W, Alharbi O, Alharbi M, Liu H, Nøhr-Meldgaard K, Mayer K, Vestergaard M, Gallagher LA, Derrick JP, McBain AJ, Biboy J, Vollmer W, O'Gara JP, Grunert T, Ingmer H, Xia G. The Novel Membrane-Associated Auxiliary Factors AuxA and AuxB Modulate β-lactam Resistance in MRSA by stabilizing Lipoteichoic Acids. Int J Antimicrob Agents 2021; 57:106283. [PMID: 33503451 DOI: 10.1016/j.ijantimicag.2021.106283] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/08/2020] [Accepted: 12/19/2020] [Indexed: 01/20/2023]
Abstract
A major determinant of β-lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) is the drug insensitive transpeptidase, PBP2a, encoded by mecA. Full expression of the resistance phenotype requires auxiliary factors. Two such factors, auxiliary factor A (auxA, SAUSA300_0980) and B (auxB, SAUSA300_1003), were identified in a screen against mutants with increased susceptibility to β-lactams in the MRSA strain, JE2. auxA and auxB encode transmembrane proteins, with AuxA predicted to be a transporter. Inactivation of auxA or auxB enhanced β-lactam susceptibility in community-, hospital- and livestock-associated MRSA strains without affecting PBP2a expression, peptidoglycan cross-linking or wall teichoic acid synthesis. Both mutants displayed increased susceptibility to inhibitors of lipoteichoic acid (LTA) synthesis and alanylation pathways and released LTA even in the absence of β-lactams. The β-lactam susceptibility of the aux mutants was suppressed by mutations inactivating gdpP, which was previously found to allow growth of mutants lacking the lipoteichoic synthase enzyme, LtaS. Using the Galleria mellonella infection model, enhanced survival of larvae inoculated with either auxA or auxB mutants was observed compared with the wild-type strain following treatment with amoxicillin. These results indicate that AuxA and AuxB are central for LTA stability and potential inhibitors can be tools to re-sensitize MRSA strains to β-lactams and combat MRSA infections.
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Affiliation(s)
- Kasper Mikkelsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Denmark
| | - Wanchat Sirisarn
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Ohood Alharbi
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Mohanned Alharbi
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Huayong Liu
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | | | - Katharina Mayer
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Martin Vestergaard
- Department of Veterinary and Animal Sciences, University of Copenhagen, Denmark
| | - Laura A Gallagher
- Department of Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Jeremy P Derrick
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Andrew J McBain
- Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, United Kingdom
| | - Jacob Biboy
- Centre for Bacterial Cell Biology, NU Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, United Kingdom
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, NU Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, United Kingdom
| | - James P O'Gara
- Department of Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Tom Grunert
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, University of Copenhagen, Denmark.
| | - Guoqing Xia
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom.
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20
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Ubiquitous selection for mecA in community-associated MRSA across diverse chemical environments. Nat Commun 2020; 11:6038. [PMID: 33247131 PMCID: PMC7695840 DOI: 10.1038/s41467-020-19825-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 10/27/2020] [Indexed: 12/14/2022] Open
Abstract
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is threatening public health as it spreads worldwide across diverse environments. Its genetic hallmark, the mecA gene, confers resistance to many β-lactam antibiotics. Here, we show that, in addition, mecA provides a broad selective advantage across diverse chemical environments. Competing fluorescently labelled wild-type and mecA-deleted CA-MRSA USA400 strains across ~57,000 compounds supplemented with subinhibitory levels of the β-lactam drug cefoxitin, we find that mecA provides a widespread advantage across β-lactam and non β-lactam antibiotics, non-antibiotic drugs and even diverse natural and synthetic compounds. This advantage depends on the presence of cefoxitin and is strongly associated with the compounds’ physicochemical properties, suggesting that it may be mediated by differential compounds permeability into the cell. Indeed, mecA protects the bacteria against increased cell-envelope permeability under subinhibitory cefoxitin treatment. Our findings suggest that CA-MRSA success might be driven by a cell-envelope mediated selective advantage across diverse chemical compounds. The mecA gene confers resistance to many β-lactam antibiotics in community-associated MRSA bacteria. Here, Snitser et al. show that mecA also provides broad selective advantage across diverse chemical environments in the presence of subinhibitory β-lactam concentrations, by protecting the bacteria against increased cell-envelope permeability.
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21
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Gallagher LA, Shears RK, Fingleton C, Alvarez L, Waters EM, Clarke J, Bricio-Moreno L, Campbell C, Yadav AK, Razvi F, O'Neill E, O'Neill AJ, Cava F, Fey PD, Kadioglu A, O'Gara JP. Impaired Alanine Transport or Exposure to d-Cycloserine Increases the Susceptibility of MRSA to β-lactam Antibiotics. J Infect Dis 2020; 221:1000-1016. [PMID: 31628459 DOI: 10.1093/infdis/jiz542] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/14/2019] [Indexed: 12/29/2022] Open
Abstract
Prolonging the clinical effectiveness of β-lactams, which remain first-line antibiotics for many infections, is an important part of efforts to address antimicrobial resistance. We report here that inactivation of the predicted d-cycloserine (DCS) transporter gene cycA resensitized methicillin-resistant Staphylococcus aureus (MRSA) to β-lactam antibiotics. The cycA mutation also resulted in hypersusceptibility to DCS, an alanine analogue antibiotic that inhibits alanine racemase and d-alanine ligase required for d-alanine incorporation into cell wall peptidoglycan. Alanine transport was impaired in the cycA mutant, and this correlated with increased susceptibility to oxacillin and DCS. The cycA mutation or exposure to DCS were both associated with the accumulation of muropeptides with tripeptide stems lacking the terminal d-ala-d-ala and reduced peptidoglycan cross-linking, prompting us to investigate synergism between β-lactams and DCS. DCS resensitized MRSA to β-lactams in vitro and significantly enhanced MRSA eradication by oxacillin in a mouse bacteremia model. These findings reveal alanine transport as a new therapeutic target to enhance the susceptibility of MRSA to β-lactam antibiotics.
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Affiliation(s)
- Laura A Gallagher
- School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Rebecca K Shears
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, United Kingdom
| | - Claire Fingleton
- School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Laura Alvarez
- Molecular Infection Medicine, Sweden, Molecular Biology Department, Umeå University, Umeå, Sweden
| | - Elaine M Waters
- School of Natural Sciences, National University of Ireland, Galway, Ireland.,Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, United Kingdom
| | - Jenny Clarke
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, United Kingdom
| | - Laura Bricio-Moreno
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, United Kingdom
| | | | - Akhilesh K Yadav
- Molecular Infection Medicine, Sweden, Molecular Biology Department, Umeå University, Umeå, Sweden
| | - Fareha Razvi
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Eoghan O'Neill
- Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Connolly Hospital, Dublin, Ireland
| | - Alex J O'Neill
- Antimicrobial Research Centre, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Felipe Cava
- Molecular Infection Medicine, Sweden, Molecular Biology Department, Umeå University, Umeå, Sweden
| | - Paul D Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Aras Kadioglu
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, United Kingdom
| | - James P O'Gara
- School of Natural Sciences, National University of Ireland, Galway, Ireland
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22
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Lactobacillus casei extracellular vesicles stimulate EGFR pathway likely due to the presence of proteins P40 and P75 bound to their surface. Sci Rep 2020; 10:19237. [PMID: 33159116 PMCID: PMC7648624 DOI: 10.1038/s41598-020-75930-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 10/16/2020] [Indexed: 12/20/2022] Open
Abstract
In the complex interplay of beneficial bacteria with the host, there are few examples of bacterial metabolites and effector molecules that have been consistently identified. Protective effects on the intestinal epithelium have been ascribed to P40 and P75, two well characterized cell wall muramidases, present in the culture supernatant of strains belonging to the taxon Lactobacillus casei/paracasei/rhamnosus. This work reports that Lactobacillus casei BL23 extracellular vesicles (BL23 EVs) have a small size (17–20 nm or 24–32 nm, depending on the method used) and contain lipoteichoic acid (LTA). Interestingly, all detected P40 and most of P75 were associated to EVs and possibly located at their external surface, as shown by proteinase K digestion. Biosensor assays showed that both proteins bind LTA and vesicles, suggesting that they could bind to ligands like LTA present on BL23 EVs. Native BL23 EVs have a moderate proinflammatory effect and they were able to induce phosphorylation of the epidermal growth factor receptor (EGFR), showing an effect similar to purified P40 and P75 and leading to the conclusion that the activity described in the supernatant (postbiotic) of these bacteria would be mainly due to P40 and P75 bound to EVs.
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23
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Pereira F, Figueiredo T, de Almeida RFM, Antunes CAC, Garcia C, Reis CP, Ascensão L, Sobral RG, Rijo P. Unveiling the Mechanism of Action of 7α-acetoxy-6β-hydroxyroyleanone on an MRSA/VISA Strain: Membrane and Cell Wall Interactions. Biomolecules 2020; 10:biom10070983. [PMID: 32630112 PMCID: PMC7408375 DOI: 10.3390/biom10070983] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/19/2020] [Accepted: 06/25/2020] [Indexed: 12/27/2022] Open
Abstract
The number of cases of failure in the treatment of infections associated with resistant bacteria is on the rise, due to the decreasing efficacy of current antibiotics. Notably, 7α-Acetoxy-6β-hydroxyroyleanone (AHR), a diterpene isolated from different Plectranthus species, showed antibacterial activity, namely against Methicillin-resistant Staphylococcus aureus (MRSA) strains. The high antibacterial activity and low cytotoxicity render this natural compound an interesting alternative against resistant bacteria. The aim of this study is to understand the mechanism of action of AHR on MRSA, using the MRSA/Vancomycin-intermediate S. aureus (VISA) strain CIP 106760, and to study the AHR effect on lipid bilayers and on the cell wall. Although AHR interacted with lipid bilayers, it did not have a significant effect on membrane passive permeability. Alternatively, bacteria treated with this royleanone displayed cell wall disruption, without revealing cell lysis. In conclusion, the results gathered so far point to a yet undescribed mode of action that needs further investigation.
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Affiliation(s)
- Filipe Pereira
- Research Center for Biosciences and Health Technologies (CBIOS), Universidade Lusófona de Humanidades e Tecnologias, Campo Grande, 376, 1749-024 Lisboa, Portugal; (F.P.); (C.G.); (C.P.R.)
- Department of Biomedical Sciences, Faculty of Pharmacy, University of Alcalá, Campus Universitario, 28871 Alcalá de Henares, Spain
| | - Teresa Figueiredo
- Departamento de Ciências da Vida, UCIBIO@REQUIMTE, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2825-149 Caparica, Portugal;
| | - Rodrigo F. M. de Almeida
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal; (R.F.M.d.A.); (C.A.C.A.)
| | - Catarina A. C. Antunes
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal; (R.F.M.d.A.); (C.A.C.A.)
| | - Catarina Garcia
- Research Center for Biosciences and Health Technologies (CBIOS), Universidade Lusófona de Humanidades e Tecnologias, Campo Grande, 376, 1749-024 Lisboa, Portugal; (F.P.); (C.G.); (C.P.R.)
- Department of Biomedical Sciences, Faculty of Pharmacy, University of Alcalá, Campus Universitario, 28871 Alcalá de Henares, Spain
| | - Catarina P. Reis
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, 1649-003 Lisboa, Portugal;
- Institute of Biophysics and Biomedical Bioengeneering (IBEB), Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Lia Ascensão
- Centro de Estudos do Ambiente e do Mar (CESAM), Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal;
| | - Rita G. Sobral
- Departamento de Ciências da Vida, UCIBIO@REQUIMTE, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2825-149 Caparica, Portugal;
- Correspondence: (R.G.S.); (P.R.); Tel.: +351-212-948-530 (R.G.S.); +351-217515500 (P.R.); Fax: +351-212-954-461 (R.G.S.); +351-217577006 (P.R.)
| | - Patricia Rijo
- Research Center for Biosciences and Health Technologies (CBIOS), Universidade Lusófona de Humanidades e Tecnologias, Campo Grande, 376, 1749-024 Lisboa, Portugal; (F.P.); (C.G.); (C.P.R.)
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, 1649-003 Lisboa, Portugal;
- Correspondence: (R.G.S.); (P.R.); Tel.: +351-212-948-530 (R.G.S.); +351-217515500 (P.R.); Fax: +351-212-954-461 (R.G.S.); +351-217577006 (P.R.)
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24
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Gajdiss M, Monk IR, Bertsche U, Kienemund J, Funk T, Dietrich A, Hort M, Sib E, Stinear TP, Bierbaum G. YycH and YycI Regulate Expression of Staphylococcus aureus Autolysins by Activation of WalRK Phosphorylation. Microorganisms 2020; 8:microorganisms8060870. [PMID: 32526915 PMCID: PMC7355866 DOI: 10.3390/microorganisms8060870] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/05/2020] [Accepted: 06/07/2020] [Indexed: 11/16/2022] Open
Abstract
Staphylococcus aureus is a facultative pathogen that can encode numerous antibiotic resistance and immune evasion genes and can cause severe infections. Reduced susceptibility to last resort antibiotics such as vancomycin and daptomycin is often associated with mutations in walRK, an essential two-component regulatory system (TCS). This study focuses on the WalK accessory membrane proteins YycH and YycI and their influence on WalRK phosphorylation. Depletion of YycH and YycI by antisense RNA caused an impaired autolysis, indicating a positive regulatory function on WalK as has been previously described. Phosphorylation assays with full-length recombinant proteins in phospholipid liposomes showed that YycH and YycI stimulate WalK activity and that both regulatory proteins are needed for full activation of the WalK kinase. This was validated in vivo through examining the phosphorylation status of WalR using Phos-tag SDS-PAGE with a yycHI deletion mutant exhibiting reduced levels of phosphorylated WalR. In the yycHI knockdown strain, muropeptide composition of the cell wall was not affected, however, the wall teichoic acid content was increased. In conclusion, a direct modulation of WalRK phosphorylation activity by the accessory proteins YycH and YycI is reported both in vitro and in vivo. Taken together, our results show that YycH and YycI are important in the direct regulation of WalRK-dependent cell wall metabolism.
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Affiliation(s)
- Mike Gajdiss
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
| | - Ian R. Monk
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC 3010, Australia; (I.R.M.); (T.P.S.)
| | - Ute Bertsche
- Department of Infection Biology, University of Tuebingen, 72076 Tuebingen, Germany;
| | - Janina Kienemund
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
| | - Tanja Funk
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
| | - Alina Dietrich
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
| | - Michael Hort
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
| | - Esther Sib
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
| | - Timothy P. Stinear
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC 3010, Australia; (I.R.M.); (T.P.S.)
| | - Gabriele Bierbaum
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, 53125 Bonn, Germany; (M.G.); (J.K.); (T.F.); (A.D.); (M.H.); (E.S.)
- Correspondence:
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25
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Scornec H, Palud A, Pédron T, Wheeler R, Petitgonnet C, Boneca IG, Cavin JF, Sansonetti PJ, Licandro H. Study of the cwaRS-ldcA Operon Coding a Two-Component System and a Putative L,D-Carboxypeptidase in Lactobacillus paracasei. Front Microbiol 2020; 11:156. [PMID: 32194510 PMCID: PMC7062640 DOI: 10.3389/fmicb.2020.00156] [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: 09/27/2019] [Accepted: 01/22/2020] [Indexed: 11/22/2022] Open
Abstract
The cell surface is the primary recognition site between the bacterium and the host. An operon of three genes, LSEI_0219 (cwaR), LSEI_0220 (cwaS), and LSEI_0221 (ldcA), has been previously identified as required for the establishment of Lactobacillus paracasei in the gut. The genes cwaR and cwaS encode a predicted two-component system (TCS) and ldcA a predicted D-alanyl-D-alanine carboxypeptidase which is a peptidoglycan (PG) biosynthesis enzyme. We explored the functionality and the physiological role of these three genes, particularly their impact on the bacterial cell wall architecture and on the bacterial adaptation to environmental perturbations in the gut. The functionality of CwaS/R proteins as a TCS has been demonstrated by biochemical analysis. It is involved in the transcriptional regulation of several genes of the PG biosynthesis. Analysis of the muropeptides of PG in mutants allowed us to re-annotate LSEI_0221 as a putative L,D-carboxypeptidase (LdcA). The absence of this protein coincided with a decrease of two surface antigens: LSEI_0020, corresponding to p40 or msp2 whose implication in the host epithelial homeostasis has been recently studied, and LSEI_2029 which has never been functionally characterized. The inactivation of each of these three genes induces susceptibility to antimicrobial peptides (hBD1, hBD2, and CCL20), which could be the main cause of the gut establishment deficiency. Thus, this operon is necessary for the presence of two surface antigens and for a suitable cell wall architecture.
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Affiliation(s)
- Hélène Scornec
- PAM UMR, AgroSup Dijon, Université de Bourgogne Franche-Comté, Dijon, France
| | - Aurore Palud
- PAM UMR, AgroSup Dijon, Université de Bourgogne Franche-Comté, Dijon, France
| | - Thierry Pédron
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- Unité INSERM, Institut Pasteur, Paris, France
| | - Richard Wheeler
- Unité de Biologie et Génétique de la Paroi Bactérienne, Institut Pasteur, Paris, France
- Avenir Group, INSERM, Paris, France
| | - Clément Petitgonnet
- PAM UMR, AgroSup Dijon, Université de Bourgogne Franche-Comté, Dijon, France
| | - Ivo Gomperts Boneca
- Unité de Biologie et Génétique de la Paroi Bactérienne, Institut Pasteur, Paris, France
- Avenir Group, INSERM, Paris, France
| | - Jean-François Cavin
- PAM UMR, AgroSup Dijon, Université de Bourgogne Franche-Comté, Dijon, France
| | - Philippe J. Sansonetti
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- Unité INSERM, Institut Pasteur, Paris, France
- Chaire de Microbiologie et Maladies Infectieuses, Collège de France, Paris, France
| | - Hélène Licandro
- PAM UMR, AgroSup Dijon, Université de Bourgogne Franche-Comté, Dijon, France
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26
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Alreshidi MM, Dunstan RH, Macdonald MM, Gottfries J, Roberts TK. The Uptake and Release of Amino Acids by Staphylococcus aureus at Mid-Exponential and Stationary Phases and Their Corresponding Responses to Changes in Temperature, pH and Osmolality. Front Microbiol 2020; 10:3059. [PMID: 32038532 PMCID: PMC6990410 DOI: 10.3389/fmicb.2019.03059] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 12/18/2019] [Indexed: 01/21/2023] Open
Abstract
Staphylococcus aureus is an important pathogen that is associated with nosocomial infections, as well as food poisoning. This bacterium is resistant to antimicrobial agents and can survive in a wide range of environmental conditions. The aim of this study was to measure the uptake and release of amino acids by S. aureus at mid-exponential and stationary phases of growth following exposure to a combination of conditions including variations in temperature, pH and NaCl. Bacterial cells were grown up to mid-exponential and stationary phases in tryptic soy broth (TSB), where the supernatants were collected for analyses of amino acids to determine the uptake and release characteristics. The uptake/release of amino acids was estimated by subtracting the initial levels of the free amino acids in the media from those measured at mid-exponential and stationary phases of growth. When cells were grown at ideal conditions, the analyses revealed that significant uptake of amino acids had occurred by stationary phase compared with the mid-exponential phase. A substantial release of valine and tyrosine into the external media was observed by cells at stationary phase. At both phases, the uptake and release patterns were significantly different between cells grown under ideal control conditions, when compared with those grown under various combinations of sub-optimal environmental conditions. The analyses of the supernatants harvested from controls and treatment groups at exponential phase indicated that the total uptake of amino acids was reduced approximately five times by cells grown with addition of 2.5% NaCl or with pH6 at 35°C, and 2-fold by cells grown at pH8 at 35°C. However, the final quantities of amino acids taken up by cells grown to stationary phase did not significantly alter between control and treated samples. Valine was found to be the most abundant amino acid that was significantly released into the media at stationary phase by both control and treated samples. It was evident that diverse environmental conditions resulted in differential patterns of amino acid uptake and release during adaptation to designated conditions.
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Affiliation(s)
- Mousa M Alreshidi
- Department of Biology, College of Sciences, University of Ha'il, Ha'il, Saudi Arabia
| | - R Hugh Dunstan
- Metabolic Research Group, Faculty of Science, School of Environmental and Life Sciences, University Drive, Callaghan, NSW, Australia
| | - Margaret M Macdonald
- Metabolic Research Group, Faculty of Science, School of Environmental and Life Sciences, University Drive, Callaghan, NSW, Australia
| | - Johan Gottfries
- Department of Chemistry, University of Gothenburg, Gothenburg, Sweden
| | - Tim K Roberts
- Metabolic Research Group, Faculty of Science, School of Environmental and Life Sciences, University Drive, Callaghan, NSW, Australia
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27
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Schuster CF, Wiedemann DM, Kirsebom FCM, Santiago M, Walker S, Gründling A. High-throughput transposon sequencing highlights the cell wall as an important barrier for osmotic stress in methicillin resistant Staphylococcus aureus and underlines a tailored response to different osmotic stressors. Mol Microbiol 2019; 113:699-717. [PMID: 31770461 PMCID: PMC7176532 DOI: 10.1111/mmi.14433] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 11/24/2019] [Indexed: 12/28/2022]
Abstract
Staphylococcus aureus is an opportunistic pathogen that can cause soft tissue infections but is also a frequent cause of foodborne illnesses. One contributing factor for this food association is its high salt tolerance allowing this organism to survive commonly used food preservation methods. How this resistance is mediated is poorly understood, particularly during long-term exposure. In this study, we used transposon sequencing (TN-seq) to understand how the responses to osmotic stressors differ. Our results revealed distinctly different long-term responses to NaCl, KCl and sucrose stresses. In addition, we identified the DUF2538 domain containing gene SAUSA300_0957 (gene 957) as essential under salt stress. Interestingly, a 957 mutant was less susceptible to oxacillin and showed increased peptidoglycan crosslinking. The salt sensitivity phenotype could be suppressed by amino acid substitutions in the transglycosylase domain of the penicillin-binding protein Pbp2, and these changes restored the peptidoglycan crosslinking to WT levels. These results indicate that increased crosslinking of the peptidoglycan polymer can be detrimental and highlight a critical role of the bacterial cell wall for osmotic stress resistance. This study will serve as a starting point for future research on osmotic stress response and help develop better strategies to tackle foodborne staphylococcal infections.
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Affiliation(s)
- Christopher F Schuster
- Section of Molecular Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - David M Wiedemann
- Section of Molecular Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Freja C M Kirsebom
- Section of Molecular Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Marina Santiago
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - Suzanne Walker
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - Angelika Gründling
- Section of Molecular Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
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28
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G C B, Sahukhal GS, Elasri MO. Role of the msaABCR Operon in Cell Wall Biosynthesis, Autolysis, Integrity, and Antibiotic Resistance in Staphylococcus aureus. Antimicrob Agents Chemother 2019; 63:e00680-19. [PMID: 31307991 PMCID: PMC6761503 DOI: 10.1128/aac.00680-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/10/2019] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus aureus is an important human pathogen in both community and health care settings. One of the challenges with S. aureus as a pathogen is its acquisition of antibiotic resistance. Previously, we showed that deletion of the msaABCR operon reduces cell wall thickness, resulting in decreased resistance to vancomycin in vancomycin-intermediate S. aureus (VISA). In this study, we investigated the nature of the cell wall defect in the msaABCR operon mutant in the Mu50 (VISA) and USA300 LAC methicillin-resistant Staphylococcus aureus (MRSA) strains. Results showed that msaABCR mutant cells had decreased cross-linking in both strains. This defect is typically due to increased murein hydrolase activity and/or nonspecific processing of murein hydrolases mediated by increased protease activity in mutant cells. The defect was enhanced by a decrease in teichoic acid content in the msaABCR mutant. Therefore, we propose that deletion of the msaABCR operon results in decreased peptidoglycan cross-linking, leading to increased susceptibility toward cell wall-targeting antibiotics, such as β-lactams and vancomycin. Moreover, we also observed significantly downregulated transcription of early cell wall-synthesizing genes, supporting the finding that msaABCR mutant cells have decreased peptidoglycan synthesis. More specifically, the msaABCR mutant in the USA300 LAC strain (MRSA) showed significantly reduced expression of the murA gene, whereas the msaABCR mutant in the Mu50 strain (VISA) showed significantly reduced expression of glmU, murA, and murD Thus, we conclude that the msaABCR operon controls the balance between cell wall synthesis and cell wall hydrolysis, which is required for maintaining a robust cell wall and acquiring resistance to cell wall-targeting antibiotics, such as vancomycin and the β-lactams.
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Affiliation(s)
- Bibek G C
- Cell and Molecular Biology, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Gyan S Sahukhal
- Cell and Molecular Biology, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Mohamed O Elasri
- Cell and Molecular Biology, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
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29
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Jensen C, Bæk KT, Gallay C, Thalsø-Madsen I, Xu L, Jousselin A, Ruiz Torrubia F, Paulander W, Pereira AR, Veening JW, Pinho MG, Frees D. The ClpX chaperone controls autolytic splitting of Staphylococcus aureus daughter cells, but is bypassed by β-lactam antibiotics or inhibitors of WTA biosynthesis. PLoS Pathog 2019; 15:e1008044. [PMID: 31518377 PMCID: PMC6760813 DOI: 10.1371/journal.ppat.1008044] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/25/2019] [Accepted: 08/26/2019] [Indexed: 12/02/2022] Open
Abstract
β-lactam antibiotics interfere with cross-linking of the bacterial cell wall, but the killing mechanism of this important class of antibiotics is not fully understood. Serendipitously we found that sub-lethal doses of β-lactams rescue growth and prevent spontaneous lysis of Staphylococcus aureus mutants lacking the widely conserved chaperone ClpX, and we reasoned that a better understanding of the clpX phenotypes could provide novel insights into the downstream effects of β-lactam binding to the PBP targets. Super-resolution imaging revealed that clpX cells display aberrant septum synthesis, and initiate daughter cell separation prior to septum completion at 30°C, but not at 37°C, demonstrating that ClpX becomes critical for coordinating the S. aureus cell cycle as the temperature decreases. FtsZ localization and dynamics were not affected in the absence of ClpX, suggesting that ClpX affects septum formation and autolytic activation downstream of Z-ring formation. Interestingly, oxacillin antagonized the septum progression defects of clpX cells and prevented lysis of prematurely splitting clpX cells. Strikingly, inhibitors of wall teichoic acid (WTA) biosynthesis that work synergistically with β-lactams to kill MRSA synthesis also rescued growth of the clpX mutant, as did genetic inactivation of the gene encoding the septal autolysin, Sle1. Taken together, our data support a model in which Sle1 causes premature splitting and lysis of clpX daughter cells unless Sle1-dependent lysis is antagonized by β-lactams or by inhibiting an early step in WTA biosynthesis. The finding that β-lactams and inhibitors of WTA biosynthesis specifically prevent lysis of a mutant with dysregulated autolytic activity lends support to the idea that PBPs and WTA biosynthesis play an important role in coordinating cell division with autolytic splitting of daughter cells, and that β-lactams do not kill S. aureus simply by weakening the cell wall. The bacterium Staphylococcus aureus is a major cause of human disease, and the rapid spread of S. aureus strains that are resistant to almost all β-lactam antibiotics has made treatment increasingly difficult. β-lactams interfere with cross-linking of the bacterial cell wall but the killing mechanism of this important class of antibiotics is not fully understood. Here we provide novel insight into this topic by examining a defined S. aureus mutant that has the unusual property of growing markedly better in the presence of β-lactams. Without β-lactams this mutant dies spontaneously at a high frequency due to premature separation of daughter cells during cell division. Cell death of the mutant can, however, be prevented either by exposure to β-lactam antibiotics or by inhibiting synthesis of wall teichoic acid, a major component of the cell wall in Gram-positive bacteria with a conserved role in activation of autolytic splitting of daughter cells. The finding that β-lactam antibiotics can prevent lysis of a mutant with deregulated activity of autolytic enzymes involved in daughter cell splitting, emphasizes the idea that β-lactams interfere with the coordination between cell division and daughter cell splitting, and do not kill S. aureus simply by weakening the cell wall.
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Affiliation(s)
- Camilla Jensen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kristoffer T. Bæk
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Clement Gallay
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Ida Thalsø-Madsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lijuan Xu
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ambre Jousselin
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Fernando Ruiz Torrubia
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Wilhelm Paulander
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ana R. Pereira
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Mariana G. Pinho
- Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Dorte Frees
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
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Rismondo J, Halbedel S, Gründling A. Cell Shape and Antibiotic Resistance Are Maintained by the Activity of Multiple FtsW and RodA Enzymes in Listeria monocytogenes. mBio 2019; 10:e01448-19. [PMID: 31387909 PMCID: PMC6686043 DOI: 10.1128/mbio.01448-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 07/08/2019] [Indexed: 12/17/2022] Open
Abstract
Rod-shaped bacteria have two modes of peptidoglycan synthesis: lateral synthesis and synthesis at the cell division site. These two processes are controlled by two macromolecular protein complexes, the elongasome and divisome. Recently, it has been shown that the Bacillus subtilis RodA protein, which forms part of the elongasome, has peptidoglycan glycosyltransferase activity. The cell division-specific RodA homolog FtsW fulfils a similar role at the divisome. The human pathogen Listeria monocytogenes carries genes that encode up to six FtsW/RodA homologs; however, their functions have not yet been investigated. Analysis of deletion and depletion strains led to the identification of the essential cell division-specific FtsW protein, FtsW1. Interestingly, L. monocytogenes carries a gene that encodes a second FtsW protein, FtsW2, which can compensate for the lack of FtsW1, when expressed from an inducible promoter. L. monocytogenes also possesses three RodA homologs, RodA1, RodA2, and RodA3, and their combined absence is lethal. Cells of a rodA1 rodA3 double mutant are shorter and have increased antibiotic and lysozyme sensitivity, probably due to a weakened cell wall. Results from promoter activity assays revealed that expression of rodA3 and ftsW2 is induced in the presence of antibiotics targeting penicillin binding proteins. Consistent with this, a rodA3 mutant was more susceptible to the β-lactam antibiotic cefuroxime. Interestingly, overexpression of RodA3 also led to increased cefuroxime sensitivity. Our study highlights that L. monocytogenes genes encode a multitude of functional FtsW and RodA enzymes to produce its rigid cell wall and that their expression needs to be tightly regulated to maintain growth, cell division, and antibiotic resistance.IMPORTANCE The human pathogen Listeria monocytogenes is usually treated with high doses of β-lactam antibiotics, often combined with gentamicin. However, these antibiotics only act bacteriostatically on L. monocytogenes, and the immune system is needed to clear the infection. Therefore, individuals with a compromised immune system are at risk to develop a severe form of Listeria infection, which can be fatal in up to 30% of cases. The development of new strategies to treat Listeria infections is necessary. Here we show that the expression of some of the FtsW and RodA enzymes of L. monocytogenes is induced by the presence of β-lactam antibiotics, and the combined absence of these enzymes makes bacteria more susceptible to this class of antibiotics. The development of antimicrobial agents that inhibit the activity or production of FtsW and RodA enzymes might therefore help to improve the treatment of Listeria infections and thereby lead to a reduction in mortality.
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Affiliation(s)
- Jeanine Rismondo
- Section of Microbiology, Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Sven Halbedel
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany
| | - Angelika Gründling
- Section of Microbiology, Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
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31
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Abstract
Chlamydiales species are obligate intracellular bacteria and important human pathogens that have a minimal division machinery lacking the proteins that are essential for bacterial division in other species, such as FtsZ. Chlamydial division requires synthesis of peptidoglycan, which forms a ring at the division septum and is rapidly turned over. However, little is known of peptidoglycan degradation, because many peptidoglycan-degrading enzymes are not encoded by chlamydial genomes. Here we show that an homologue of SpoIID, a peptidoglycan-degrading enzyme involved in sporulation of bacteria such as Bacillus subtilis, is expressed in Chlamydiales, localizes at the division septum, and degrades peptidoglycan in vitro, indicating that SpoIID is not only involved in sporulation but also likely implicated in division of some bacteria. Chlamydiales species are obligate intracellular bacteria lacking a classical peptidoglycan sacculus but relying on peptidoglycan synthesis for cytokinesis. While septal peptidoglycan biosynthesis seems to be regulated by MreB actin and its membrane anchor RodZ rather than FtsZ tubulin in Chlamydiales, the mechanism of peptidoglycan remodeling is poorly understood. An amidase conserved in Chlamydiales is able to cleave peptide stems in peptidoglycan, but it is not clear how peptidoglycan glycan strands are cleaved since no classical lytic transglycosylase is encoded in chlamydial genomes. However, a protein containing a SpoIID domain, known to possess transglycosylase activity in Bacillus subtilis, is conserved in Chlamydiales. We show here that the SpoIID homologue of the Chlamydia-related pathogen Waddlia chondrophila is a septal peptidoglycan-binding protein. Moreover, we demonstrate that SpoIID acts as a lytic transglycosylase on peptidoglycan and as a muramidase on denuded glycan strands in vitro. As SpoIID-like proteins are widespread in nonsporulating bacteria, SpoIID might commonly be a septal peptidoglycan remodeling protein in bacteria, including obligate intracellular pathogens, and thus might represent a promising drug target.
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Schneewind O, Missiakas DM. Staphylococcal Protein Secretion and Envelope Assembly. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0070-2019. [PMID: 31267890 PMCID: PMC7028390 DOI: 10.1128/microbiolspec.gpp3-0070-2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Indexed: 12/13/2022] Open
Abstract
The highly cross-linked peptidoglycan represents the rigid layer of the bacterial envelope and protects bacteria from osmotic lysis. In Gram-positive bacteria, peptidoglycan also functions as a scaffold for the immobilization of capsular polysaccharide, wall teichoic acid (WTA), and surface proteins. This chapter captures recent development on the assembly of the envelope of Staphylococcus aureus including mechanisms accounting for immobilization of molecules to peptidoglycan as well as hydrolysis of peptidoglycan for the specific release of bound molecules, facilitation of protein secretion across the envelope and cell division. Peptidoglycan, WTA and capsular polysaccharide are directly synthesized onto undecaprenol. Surface proteins are anchored by Sortase A, a membrane-embedded transpeptidase that scans secreted polypeptides for the C-terminal LPXTG motif of sorting signals. The resulting acyl enzyme intermediate is resolved by lipid II, the undecaprenol-bound peptidoglycan precursor. While these pathways share membrane diffusible undecaprenol, assembly of these molecules occurs either at the cross-walls or the cell poles. In S. aureus, the cross-wall represents the site of de novo peptidoglycan synthesis which is eventually split to complete the cell cycle yielding newly divided daughter cells. Peptidoglycan synthesized at the cross-wall is initially devoid of WTA. Conversely, lipoteichoic acid (LTA) synthesis which does not require bactoprenol is seemingly restricted to septal membranes. Similarly, S. aureus distinguishes two types of surface protein precursors. Polypeptides with canonical signal peptides are deposited at the cell poles, whereas precursors with conserved YSIRK-GXXS motif signal peptides traffic to the cross-wall. A model for protein trafficking in the envelope and uneven distribution of teichoic acids is discussed.
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Affiliation(s)
- Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, IL 60637
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33
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Abstract
Dating back to the 1960s, initial studies on the staphylococcal cell wall were driven by the need to clarify the mode of action of the first antibiotics and the resistance mechanisms developed by the bacteria. During the following decades, the elucidation of the biosynthetic path and primary composition of staphylococcal cell walls was propelled by advances in microbial cell biology, specifically, the introduction of high-resolution analytical techniques and molecular genetic approaches. The field of staphylococcal cell wall gradually gained its own significance as the complexity of its chemical structure and involvement in numerous cellular processes became evident, namely its versatile role in host interactions, coordination of cell division and environmental stress signaling.This chapter includes an updated description of the anatomy of staphylococcal cell walls, paying particular attention to information from the last decade, under four headings: high-resolution analysis of the Staphylococcus aureus peptidoglycan; variations in peptidoglycan composition; genetic determinants and enzymes in cell wall synthesis; and complex functions of cell walls. The latest contributions to a more precise picture of the staphylococcal cell envelope were possible due to recently developed state-of-the-art microscopy and spectroscopy techniques and to a wide combination of -omics approaches, that are allowing to obtain a more integrative view of this highly dynamic structure.
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Affiliation(s)
- Rita Sobral
- UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
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34
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Alreshidi MM, Dunstan RH, Macdonald MM, Smith ND, Gottfries J, Roberts TK. Amino acids and proteomic acclimation of Staphylococcus aureus when incubated in a defined minimal medium supplemented with 5% sodium chloride. Microbiologyopen 2019; 8:e00772. [PMID: 30739392 PMCID: PMC6562129 DOI: 10.1002/mbo3.772] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 10/31/2018] [Accepted: 10/31/2018] [Indexed: 11/06/2022] Open
Abstract
Staphylococcus aureus is a versatile bacterium that can adapt to survive and grow in a wide range of salt concentrations. This study investigated whether the cells could mount a response to survive a challenge of 5% NaCl in a minimal incubation medium that would not support cell replication. Cells were grown in liquid culture, washed and then incubated for 90 min at 37°C in a medium that contained only glycine and glucose as substrates in PBS plus trace elements. The control cells were compared with a treatment group which was incubated with an additional 5% NaCl. Significantly more glycine was taken up by the cells exposed to 5% NaCl compared with control cells, and both groups consumed 99% of the glucose supplied. The NaCl treated cells had significantly higher cytoplasmic levels of proline and glutamic acid as well as lower levels of alanine and methionine compared with the controls (p < 0.05). The levels of the two major cytoplasmic amino acids, aspartic acid and glycine, remained constant in control and treated cells. Proteomic analyses revealed that 10 proteins showed differential responses between the control and treatment groups. The reductions in proteins were primarily associated with processes of protein biosynthesis, pathogenicity, and cell adhesion. Since cell numbers remained constant during the incubation period in minimal medium, it was concluded that there was no cell division to support population growth. The results provided evidence that the cells in the minimal medium exposed to the NaCl treatment underwent in situ homeostatic changes to adjust to the new environmental conditions. It was proposed that this represented a phenotypic shift to form cells akin to small colony variants, with lower metabolic rates and lower levels of key proteins associated with pathogenicity.
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Affiliation(s)
- Mousa M. Alreshidi
- Department of Biology, College of ScienceUniversity of HailHailSaudi Arabia
| | - R. Hugh Dunstan
- Metabolic Research Group, Faculty of ScienceSchool of Environmental and Life SciencesCallaghanNew South WalesAustralia
| | - Margaret M. Macdonald
- Metabolic Research Group, Faculty of ScienceSchool of Environmental and Life SciencesCallaghanNew South WalesAustralia
| | - Nathan D. Smith
- Analytical and Biomolecular Research Facility (ABRF)University of NewcastleCallaghanNew South WalesAustralia
| | - Johan Gottfries
- Department of ChemistryGothenburg UniversityGothenburgSweden
| | - Tim K. Roberts
- Metabolic Research Group, Faculty of ScienceSchool of Environmental and Life SciencesCallaghanNew South WalesAustralia
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35
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Monteiro JM, Covas G, Rausch D, Filipe SR, Schneider T, Sahl HG, Pinho MG. The pentaglycine bridges of Staphylococcus aureus peptidoglycan are essential for cell integrity. Sci Rep 2019; 9:5010. [PMID: 30899062 PMCID: PMC6428869 DOI: 10.1038/s41598-019-41461-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 03/07/2019] [Indexed: 02/04/2023] Open
Abstract
Bacterial cells are surrounded by cell wall, whose main component is peptidoglycan (PG), a macromolecule that withstands the internal turgor of the cell. PG composition can vary considerably between species. The Gram-positive pathogen Staphylococcus aureus possesses highly crosslinked PG due to the presence of cross bridges containing five glycines, which are synthesised by the FemXAB protein family. FemX adds the first glycine of the cross bridge, while FemA and FemB add the second and the third, and the fourth and the fifth glycines, respectively. Of these, FemX was reported to be essential. To investigate the essentiality of FemAB, we constructed a conditional S. aureus mutant of the femAB operon. Depletion of femAB was lethal, with cells appearing as pseudomulticellular forms that eventually lyse due to extensive membrane rupture. This deleterious effect was mitigated by drastically increasing the osmolarity of the medium, indicating that pentaglycine crosslinks are required for S. aureus cells to withstand internal turgor. Despite the absence of canonical membrane targeting domains, FemA has been shown to localise at the membrane. To study its mechanism of localisation, we constructed mutants in key residues present in the putative transferase pocket and the α6 helix of FemA, possibly involved in tRNA binding. Mutations in the α6 helix led to a sharp decrease in protein activity in vivo and in vitro but did not impair correct membrane localisation, indicating that FemA activity is not required for localisation. Our data indicates that, contrarily to what was previously thought, S. aureus cells do not survive in the absence of a pentaglycine cross bridge.
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Affiliation(s)
- João M Monteiro
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Gonçalo Covas
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.,UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Daniela Rausch
- Institute of Pharmaceutical Microbiology, University of Bonn, 53115, Bonn, Germany
| | - Sérgio R Filipe
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.,UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Tanja Schneider
- Institute of Pharmaceutical Microbiology, University of Bonn, 53115, Bonn, Germany
| | - Hans-Georg Sahl
- Institute of Pharmaceutical Microbiology, University of Bonn, 53115, Bonn, Germany
| | - Mariana G Pinho
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
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Chateau A, Schneewind O, Missiakas D. Extraction and Purification of Wall-Bound Polymers of Gram-Positive Bacteria. Methods Mol Biol 2019; 1954:47-57. [PMID: 30864123 DOI: 10.1007/978-1-4939-9154-9_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The envelope of gram-positive bacteria encompasses the cell wall, a rigid exoskeleton comprised of peptidoglycan that provides protection against lysis and governs bacterial cell shapes. Peptidoglycan also serves as the site of attachment for proteins and nonproteinaceous polymers that interact with the bacterial environment. Nonproteinaceous molecules include teichoic acids, capsular polysaccharides, and secondary cell wall polysaccharides (SCWP). Treatment of gram-positive bacterial cells with proteases, nucleases, and detergents results in the isolation of "murein sacculi" (i.e., peptidoglycan with bound carbohydrate polymers). Incubation of sacculi with acid or base releases carbohydrate polymers that can be purified for further biochemical characterization. This protocol describes the hydrofluoric acid extraction and purification of the secondary cell wall polymer of Bacillus anthracis that is also found in the envelope of the other members of the Bacillus cereus sensu lato group of bacteria.
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Affiliation(s)
- Alice Chateau
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, IL, USA.,Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Olaf Schneewind
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, IL, USA.,Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Dominique Missiakas
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, IL, USA. .,Department of Microbiology, University of Chicago, Chicago, IL, USA.
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37
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Wandiyanto JV, Cheeseman S, Truong VK, Kobaisi MA, Bizet C, Juodkazis S, Thissen H, Crawford RJ, Ivanova EP. Outsmarting superbugs: bactericidal activity of nanostructured titanium surfaces against methicillin- and gentamicin-resistantStaphylococcus aureusATCC 33592. J Mater Chem B 2019. [DOI: 10.1039/c9tb00102f] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The colonisation of biomaterial surfaces by pathogenic bacteria is a significant issue of concern, particularly in light of the rapid rise of antibiotic resistance.
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Affiliation(s)
- Jason V. Wandiyanto
- School of Science
- Faculty of Science
- Engineering and Technology
- Swinburne University of Technology
- Hawthorn 3122 VIC
| | - Samuel Cheeseman
- School of Science
- College of Science
- Engineering and Health
- RMIT University
- Melbourne 3000 VIC
| | - Vi Khanh Truong
- School of Science
- College of Science
- Engineering and Health
- RMIT University
- Melbourne 3000 VIC
| | - Mohammad Al Kobaisi
- School of Science
- Faculty of Science
- Engineering and Technology
- Swinburne University of Technology
- Hawthorn 3122 VIC
| | | | - Saulius Juodkazis
- Centre for Micro-Photonics
- Faculty of Science
- Engineering and Technology
- Swinburne University of Technology
- Hawthorn 3122 VIC
| | | | - Russell J. Crawford
- School of Science
- College of Science
- Engineering and Health
- RMIT University
- Melbourne 3000 VIC
| | - Elena P. Ivanova
- School of Science
- College of Science
- Engineering and Health
- RMIT University
- Melbourne 3000 VIC
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38
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Inactivation of the Monofunctional Peptidoglycan Glycosyltransferase SgtB Allows Staphylococcus aureus To Survive in the Absence of Lipoteichoic Acid. J Bacteriol 2018; 201:JB.00574-18. [PMID: 30322854 PMCID: PMC6287468 DOI: 10.1128/jb.00574-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 10/08/2018] [Indexed: 12/29/2022] Open
Abstract
The bacterial cell wall acts as a primary defense against environmental insults such as changes in osmolarity. It is also a vulnerable structure, as defects in its synthesis can lead to growth arrest or cell death. The important human pathogen Staphylococcus aureus has a typical Gram-positive cell wall, which consists of peptidoglycan and the anionic polymers LTA and wall teichoic acid. Several clinically relevant antibiotics inhibit the synthesis of peptidoglycan; therefore, it and teichoic acids are considered attractive targets for the development of new antimicrobials. We show that LTA is required for efficient peptidoglycan cross-linking in S. aureus and inactivation of a peptidoglycan glycosyltransferase can partially rescue this defect, together revealing an intimate link between peptidoglycan and LTA synthesis. The cell wall of Staphylococcus aureus is composed of peptidoglycan and the anionic polymers lipoteichoic acid (LTA) and wall teichoic acid. LTA is required for growth and normal cell morphology in S. aureus. Strains lacking LTA are usually viable only when grown under osmotically stabilizing conditions or after the acquisition of compensatory mutations. LTA-negative suppressor strains with inactivating mutations in gdpP, which resulted in increased intracellular c-di-AMP levels, were described previously. Here, we sought to identify factors other than c-di-AMP that allow S. aureus to survive without LTA. LTA-negative strains able to grow in unsupplemented medium were obtained and found to contain mutations in sgtB, mazE, clpX, or vraT. The growth improvement through mutations in mazE and sgtB was confirmed by complementation analysis. We also showed that an S. aureussgtB transposon mutant, with the monofunctional peptidoglycan glycosyltransferase SgtB inactivated, displayed a 4-fold increase in the MIC of oxacillin, suggesting that alterations in the peptidoglycan structure could help bacteria compensate for the lack of LTA. Muropeptide analysis of peptidoglycans isolated from a wild-type strain and sgtB mutant strain did not reveal any sizable alterations in the peptidoglycan structure. In contrast, the peptidoglycan isolated from an LTA-negative ltaS mutant strain showed a significant reduction in the fraction of highly cross-linked peptidoglycan, which was partially rescued in the sgtB ltaS double mutant suppressor strain. Taken together, these data point toward an important function of LTA in cell wall integrity through its necessity for proper peptidoglycan assembly. IMPORTANCE The bacterial cell wall acts as a primary defense against environmental insults such as changes in osmolarity. It is also a vulnerable structure, as defects in its synthesis can lead to growth arrest or cell death. The important human pathogen Staphylococcus aureus has a typical Gram-positive cell wall, which consists of peptidoglycan and the anionic polymers LTA and wall teichoic acid. Several clinically relevant antibiotics inhibit the synthesis of peptidoglycan; therefore, it and teichoic acids are considered attractive targets for the development of new antimicrobials. We show that LTA is required for efficient peptidoglycan cross-linking in S. aureus and inactivation of a peptidoglycan glycosyltransferase can partially rescue this defect, together revealing an intimate link between peptidoglycan and LTA synthesis.
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39
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EssH Peptidoglycan Hydrolase Enables Staphylococcus aureus Type VII Secretion across the Bacterial Cell Wall Envelope. J Bacteriol 2018; 200:JB.00268-18. [PMID: 30082459 DOI: 10.1128/jb.00268-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/31/2018] [Indexed: 11/20/2022] Open
Abstract
The ESAT-6-like secretion system (ESS) of Staphylococcus aureus is assembled in the bacterial membrane from core components that promote the secretion of WXG-like proteins (EsxA, EsxB, EsxC, and EsxD) and the EssD effector. Genes encoding the ESS secretion machinery components, effector, and WXG-like proteins are located in the ess locus. Here, we identify essH, a heretofore uncharacterized gene of the ess locus, whose product is secreted via an N-terminal signal peptide into the extracellular medium of staphylococcal cultures. EssH exhibits two peptidoglycan hydrolase activities, cleaving the pentaglycine cross bridge and the amide bond of N-acetylmuramyl-l-alanine, thereby separating glycan chains and wall peptides with cleaved cross bridges. Unlike other peptidoglycan hydrolases, EssH does not promote the lysis of staphylococci. EssH residues Cys199 and His254, which are conserved in other CHAP domain enzymes, are required for peptidoglycan hydrolase activity and for S. aureus ESS secretion. These data suggest that EssH and its murein hydrolase activity are required for protein secretion by the ESS pathway.IMPORTANCE Gene clusters encoding WXG-like proteins and FtsK/SpoIIIE-like P loop ATPases in Firmicutes encode type 7b secretion systems (T7bSS) for the transport of select protein substrates. The Staphylococcus aureus T7bSS assembles in the bacterial membrane and promotes the secretion of WXG-like proteins and effectors. The mechanisms whereby staphylococci extend the T7SS across the bacterial cell wall envelope are not known. Here, we show that staphylococci secrete EssH to cleave their peptidoglycan, thereby enabling T7bSS transport of proteins across the bacterial cell wall envelope.
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40
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Adaptive Metabolism in Staphylococci: Survival and Persistence in Environmental and Clinical Settings. J Pathog 2018; 2018:1092632. [PMID: 30327733 PMCID: PMC6171259 DOI: 10.1155/2018/1092632] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/28/2018] [Accepted: 08/12/2018] [Indexed: 01/04/2023] Open
Abstract
Staphylococci are highly successful at colonizing a variety of dynamic environments, both nonpathogenic and those of clinical importance, and comprise the list of pathogens of global public health significance. Their remarkable survival and persistence can be attributed to a host of strategies, one of which is metabolic versatility—their ability to rapidly alter their metabolism in the presence of transient or long-term bacteriostatic and bactericidal conditions and facilitate cellular homeostasis. These attributes contribute to their widespread dissemination and challenging eradication particularly from clinical settings. The study of microbial behaviour at the metabolite level provides insight into mechanisms of survival and persistence under defined environmental and clinical conditions. This paper reviews the range of metabolic modulations that facilitate staphylococcal acclimatization and persistence in varying terrestrial and host conditions, and their public health ramifications in these settings.
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Azam AH, Hoshiga F, Takeuchi I, Miyanaga K, Tanji Y. Analysis of phage resistance in Staphylococcus aureus SA003 reveals different binding mechanisms for the closely related Twort-like phages ɸSA012 and ɸSA039. Appl Microbiol Biotechnol 2018; 102:8963-8977. [DOI: 10.1007/s00253-018-9269-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/15/2018] [Accepted: 07/22/2018] [Indexed: 02/01/2023]
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Tran N, Rybak MJ. β-Lactam Combinations with Vancomycin Show Synergistic Activity against Vancomycin-Susceptible Staphylococcus aureus, Vancomycin-Intermediate S. aureus (VISA), and Heterogeneous VISA. Antimicrob Agents Chemother 2018; 62:e00157-18. [PMID: 29555635 PMCID: PMC5971571 DOI: 10.1128/aac.00157-18] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/09/2018] [Indexed: 12/21/2022] Open
Abstract
Increasing utilization of vancomycin due to the high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infections has led to the emergence of vancomycin-intermediate S. aureus (VISA) and heterogeneous VISA (hVISA) strains. In vitro data suggest the potential for potent synergy between several beta-lactams and vancomycin. The objective of this study is to evaluate the synergy between beta-lactams and vancomycin against MRSA that is vancomycin susceptible, vancomycin-susceptible Staphylococcus aureus (VSSA), hVISA, and VISA. Fifty randomly selected clinical MRSA strains with various susceptibility levels to vancomycin were evaluated for vancomycin alone and vancomycin in combination with various concentrations of cefazolin (CFZ), cefepime (FEP), ceftaroline (CPT), and nafcillin (NAF). The potential for synergy was assessed by 24-h time-kill studies. Beta-lactams reduced vancomycin MIC values against all strains (4- to 16-fold reduction). In time-kill studies against MRSA, CFZ, FEP, CPT, and NAF all demonstrated similar degrees of killing at 24 h, and all showed synergistic activity with vancomycin against VSSA, hVISA, and VISA. Each of these combinations was also superior to any single agent against isolates of all three phenotypes, and each was bactericidal (P < 0.001 for all comparisons). All single-agent exposures demonstrated no activity at 24 h. The combination of vancomycin and beta-lactams significantly improved antibacterial activity against VSSA, hVISA, and VISA strains compared to the activity of any agent alone, supporting the potential use of vancomycin-beta-lactam combination therapy in infections caused by MRSA. Further clinical research is warranted to investigate the synergy of vancomycin against these Staphylococcus strains.
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Affiliation(s)
- Nikki Tran
- Anti-Infective Research Laboratory, Department of Pharmacy Practice, Eugene Applebaum College of Pharmacy and Health Sciences, Detroit, Michigan, USA
| | - Michael J Rybak
- Anti-Infective Research Laboratory, Department of Pharmacy Practice, Eugene Applebaum College of Pharmacy and Health Sciences, Detroit, Michigan, USA
- Wayne State University School of Medicine, Detroit, Michigan, USA
- Detroit Receiving Hospital, Detroit, Michigan, USA
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Abstract
In the last decade, more and more plant receptors for complex carbohydrate structures have been described. However, studies on receptor binding to glycan ligands are often hampered due to the technical challenge to obtain pure preparations of homogeneous carbohydrate ligands such as bacterial peptidoglycan (PGN) in amounts suitable for studying protein-glycan interactions. Also, most approaches rely on the availability of defined soluble ligands, which in the case of glycans can rarely be synthesized but have to be purified from the respective microorganism. In this chapter, we describe the purification of complex PGN from sources such as gram-positive bacteria, from which PGN isolation is facilitated due to its larger content in their cell wall. Insoluble PGN can subsequently be used in simple carbohydrate pull-down assays to test for interaction with plant proteins. In this respect, lysin motif (LysM)-domain containing proteins are of particular interest. All plant receptors described to date to be involved in the perception of N-Acetylglucosamine-containing ligands (such as PGN or chitin) have been shown to belong to this protein class. Thus, this chapter will also include the production of recombinant LysM proteins to analyze their PGN interaction.
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Hu Y, Zheng Q, Wanek W. Flux Analysis of Free Amino Sugars and Amino Acids in Soils by Isotope Tracing with a Novel Liquid Chromatography/High Resolution Mass Spectrometry Platform. Anal Chem 2017; 89:9192-9200. [PMID: 28776982 PMCID: PMC5605124 DOI: 10.1021/acs.analchem.7b01938] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
Soil fluxomics analysis can provide
pivotal information for understanding
soil biochemical pathways and their regulation, but direct measurement
methods are rare. Here, we describe an approach to measure soil extracellular
metabolite (amino sugar and amino acid) concentrations and fluxes
based on a 15N isotope pool dilution technique via liquid
chromatography and high-resolution mass spectrometry. We produced
commercially unavailable 15N and 13C labeled
amino sugars and amino acids by hydrolyzing peptidoglycan isolated
from isotopically labeled bacterial biomass and used them as tracers
(15N) and internal standards (13C). High-resolution
(Orbitrap Exactive) MS with a resolution of 50 000 allowed
us to separate different stable isotope labeled analogues across a
large range of metabolites. The utilization of 13C internal
standards greatly improved the accuracy and reliability of absolute
quantification. We successfully applied this method to two types of
soils and quantified the extracellular gross fluxes of 2 amino sugars,
18 amino acids, and 4 amino acid enantiomers. Compared to the influx
and efflux rates of most amino acids, similar ones were found for
glucosamine, indicating that this amino sugar is released through
peptidoglycan and chitin decomposition and serves as an important
nitrogen source for soil microorganisms. d-Alanine and d-glutamic acid derived from peptidoglycan decomposition exhibited
similar turnover rates as their l-enantiomers. This novel
approach offers new strategies to advance our understanding of the
production and transformation pathways of soil organic N metabolites,
including the unknown contributions of peptidoglycan and chitin decomposition
to soil organic N cycling.
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Affiliation(s)
- Yuntao Hu
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, Research Network "Chemistry meets Microbiology", University of Vienna , Althanstraße 14, 1090 Vienna, Austria
| | - Qing Zheng
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, Research Network "Chemistry meets Microbiology", University of Vienna , Althanstraße 14, 1090 Vienna, Austria
| | - Wolfgang Wanek
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, Research Network "Chemistry meets Microbiology", University of Vienna , Althanstraße 14, 1090 Vienna, Austria
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Whitney JC, Peterson SB, Kim J, Pazos M, Verster AJ, Radey MC, Kulasekara HD, Ching MQ, Bullen NP, Bryant D, Goo YA, Surette MG, Borenstein E, Vollmer W, Mougous JD. A broadly distributed toxin family mediates contact-dependent antagonism between gram-positive bacteria. eLife 2017; 6. [PMID: 28696203 PMCID: PMC5555719 DOI: 10.7554/elife.26938] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/10/2017] [Indexed: 12/24/2022] Open
Abstract
The Firmicutes are a phylum of bacteria that dominate numerous polymicrobial habitats of importance to human health and industry. Although these communities are often densely colonized, a broadly distributed contact-dependent mechanism of interbacterial antagonism utilized by Firmicutes has not been elucidated. Here we show that proteins belonging to the LXG polymorphic toxin family present in Streptococcus intermedius mediate cell contact- and Esx secretion pathway-dependent growth inhibition of diverse Firmicute species. The structure of one such toxin revealed a previously unobserved protein fold that we demonstrate directs the degradation of a uniquely bacterial molecule required for cell wall biosynthesis, lipid II. Consistent with our functional data linking LXG toxins to interbacterial interactions in S. intermedius, we show that LXG genes are prevalent in the human gut microbiome, a polymicrobial community dominated by Firmicutes. We speculate that interbacterial antagonism mediated by LXG toxins plays a critical role in shaping Firmicute-rich bacterial communities. DOI:http://dx.doi.org/10.7554/eLife.26938.001 Most bacteria live in densely colonized environments, such as the human gut, in which they must constantly compete with other microbes for space and nutrients. As a result, bacteria have evolved a wide array of strategies to directly fight their neighbors. For example, some bacteria release antimicrobial compounds into their surroundings, while others ‘inject’ protein toxins directly into adjacent cells. Bacteria can be classified into two groups known as Gram-positive and Gram-negative. Previous studies found that Gram-negative bacteria inject toxins into neighboring cells, but no comparable toxins in Gram-positive bacteria had been identified. Before a bacterium can inject molecules into an adjacent cell, it needs to move the toxins from its interior to the cell surface. It had been suggested that a transport system in Gram-positive bacteria called the Esx pathway may export toxins known as LXG proteins. However, it was not clear whether these proteins help Gram-positive bacteria to compete against other bacteria. Whitney et al. studied the LXG proteins in Gram-positive bacteria known as Firmicutes. The experiments reveal that Firmicutes found in the human gut possess LXG genes. A Firmicute known as Streptococcus intermedius produces three LXG proteins that are all toxic to bacteria. To avoid being harmed by its own LXG proteins, S. intermedius also produces matching antidote proteins. Further experiments show that LXG proteins are exported out of S. intermedius cells and into adjacent competitor bacteria by the Esx pathway. Examining one of these LXG proteins in more detail showed that it can degrade a molecule that bacteria need to make their cell wall. Together, these findings suggest that LXG proteins may influence the species living in many important microbial communities, including the human gut. Changes in the communities of gut microbes have been linked with many diseases. Therefore, understanding more about how the LXG proteins work may help us to develop ways to manipulate these communities to improve human health. DOI:http://dx.doi.org/10.7554/eLife.26938.002
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Affiliation(s)
- John C Whitney
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - S Brook Peterson
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - Jungyun Kim
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - Manuel Pazos
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle, United Kingdom
| | - Adrian J Verster
- Department of Genome Sciences, University of Washington, Seattle, United States
| | - Matthew C Radey
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - Hemantha D Kulasekara
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - Mary Q Ching
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States
| | - Nathan P Bullen
- Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Diane Bryant
- Experimental Systems Group, Advanced Light Source, Berkeley, United States
| | - Young Ah Goo
- Northwestern Proteomics Core Facility, Northwestern University, Chicago, United States
| | - Michael G Surette
- Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada.,Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Canada
| | - Elhanan Borenstein
- Department of Genome Sciences, University of Washington, Seattle, United States.,Department of Computer Science and Engineering, University of Washington, Seattle, United States.,Santa Fe Institute, Santa Fe, United States
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle, United Kingdom
| | - Joseph D Mougous
- Department of Microbiology, University of Washington School of Medicine, Seattle, United States.,Howard Hughes Medical Institute, University of Washington School of Medicine, Seattle, United States
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46
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High-Level Resistance of Staphylococcus aureus to β-Lactam Antibiotics Mediated by Penicillin-Binding Protein 4 (PBP4). Antimicrob Agents Chemother 2017; 61:AAC.02727-16. [PMID: 28373193 DOI: 10.1128/aac.02727-16] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 03/26/2017] [Indexed: 02/05/2023] Open
Abstract
Penicillin-binding protein 4 (PBP4), a nonessential, low-molecular-weight penicillin-binding protein of Staphylococcus aureus, has been implicated in low-level resistance to β-lactam antibiotics, although the mechanism is unknown. Mutations in PBP4 and its promoter were identified in a laboratory-generated mutant strain, CRB, which expresses high-level resistance to β-lactams, including resistance to the new-generation cephalosporins active against methicillin-resistant strains of S. aureus These mutations did not appreciably alter the β-lactam antibiotic binding affinity of purified recombinant mutant PBP4 compared to that of wild-type PBP4. Compared to the susceptible parent strain, COLnex, the CRB strain produces a highly cross-linked cell wall peptidoglycan, indicative of increased transpeptidase activity. The pbp4 promoter mutation of CRB was associated with greatly increased amounts of PBP4 in membranes compared to those in the COLnex parent. Replacement of the native promoter of COLnex with the mutant promoter of CRB resulted in increased amounts of PBP4 in membranes and a highly cross-linked cell wall. PBP4 can be repurposed to provide essential transpeptidase activity in vivo and confer high-level resistance to β-lactam antibiotics, such as ceftobiprole and ceftaroline.
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47
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Cserti E, Rosskopf S, Chang YW, Eisheuer S, Selter L, Shi J, Regh C, Koert U, Jensen GJ, Thanbichler M. Dynamics of the peptidoglycan biosynthetic machinery in the stalked budding bacteriumHyphomonas neptunium. Mol Microbiol 2017; 103:875-895. [DOI: 10.1111/mmi.13593] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Emöke Cserti
- Faculty of Biology; Philipps-Universität; Marburg 35043 Germany
- Max Planck Institute for Terrestrial Microbiology; Marburg 35043 Germany
| | - Sabine Rosskopf
- Faculty of Biology; Philipps-Universität; Marburg 35043 Germany
| | - Yi-Wei Chang
- Division of Biology and Bioengineering; California Institute of Technology; Pasadena CA 91125 USA
| | - Sabrina Eisheuer
- Faculty of Biology; Philipps-Universität; Marburg 35043 Germany
- Max Planck Institute for Terrestrial Microbiology; Marburg 35043 Germany
| | - Lars Selter
- Faculty of Chemistry; Philipps-Universität; Marburg Germany
| | - Jian Shi
- Division of Biology and Bioengineering; California Institute of Technology; Pasadena CA 91125 USA
| | - Christina Regh
- Faculty of Biology; Philipps-Universität; Marburg 35043 Germany
| | - Ulrich Koert
- Faculty of Chemistry; Philipps-Universität; Marburg Germany
| | - Grant J. Jensen
- Division of Biology and Bioengineering; California Institute of Technology; Pasadena CA 91125 USA
- Howard Hughes Medical Institute, California Institute of Technology; Pasadena CA 91125 USA
| | - Martin Thanbichler
- Faculty of Biology; Philipps-Universität; Marburg 35043 Germany
- Max Planck Institute for Terrestrial Microbiology; Marburg 35043 Germany
- LOEWE Center for Synthetic Microbiology; Marburg 35043 Germany
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48
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Guignard B, Majcherczyk PA, Monachon C, Vouillamoz J, Moreillon P. Muropeptide signature of inhibitors of protein synthesis correlates with β-lactam synergism against methicillin-resistant Staphylococcus aureus. Int J Antimicrob Agents 2017; 49:53-61. [DOI: 10.1016/j.ijantimicag.2016.09.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 09/17/2016] [Indexed: 11/26/2022]
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49
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Molecular Bases Determining Daptomycin Resistance-Mediated Resensitization to β-Lactams (Seesaw Effect) in Methicillin-Resistant Staphylococcus aureus. Antimicrob Agents Chemother 2016; 61:AAC.01634-16. [PMID: 27795377 DOI: 10.1128/aac.01634-16] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/12/2016] [Indexed: 12/18/2022] Open
Abstract
Antimicrobial resistance is recognized as one of the principal threats to public health worldwide, yet the problem is increasing. Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) strains are among the most difficult to treat in clinical settings due to the resistance of MRSA to nearly all available antibiotics. The cyclic anionic lipopeptide antibiotic daptomycin (DAP) is the clinical mainstay of anti-MRSA therapy. The decreased susceptibility to DAP (DAP resistance [DAPr]) reported in MRSA is frequently accompanied by a paradoxical decrease in β-lactam resistance, a process known as the "seesaw effect." Despite the observed discordance in resistance phenotypes, the combination of DAP and β-lactams has been proven to be clinically effective for the prevention and treatment of infections due to DAPr MRSA strains. However, the mechanisms underlying the interactions between DAP and β-lactams are largely unknown. In the study described here, we studied the role of mprF with DAP-induced mutations in β-lactam sensitization and its involvement in the effective killing by the DAP-oxacillin (OXA) combination. DAP-OXA-mediated effects resulted in cell wall perturbations, including changes in peptidoglycan insertion, penicillin-binding protein 2 (PBP 2) delocalization, and reduced membrane amounts of PBP 2a, despite the increased transcription of mecA through mec regulatory elements. We have found that the VraSR sensor-regulator is a key component of DAP resistance, triggering mutated mprF-mediated cell membrane (CM) modifications that result in impairment of PrsA location and chaperone functions, both of which are essential for PBP 2a maturation, the key determinant of β-lactam resistance. These observations provide for the first time evidence that synergistic effects between DAP and β-lactams involve PrsA posttranscriptional regulation of CM-associated PBP 2a.
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50
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Di Gregorio S, Fernandez S, Cuirolo A, Verlaine O, Amoroso A, Mengin-Lecreulx D, Famiglietti A, Joris B, Mollerach M. Different Vancomycin-Intermediate Staphylococcus aureus Phenotypes Selected from the Same ST100-hVISA Parental Strain. Microb Drug Resist 2016; 23:44-50. [PMID: 27991847 PMCID: PMC5206683 DOI: 10.1089/mdr.2016.0160] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The aim of this study is to characterize the factors related to peptidoglycan metabolism in isogenic hVISA/VISA ST100 strains. Recently, we reported the increase in IS256 transposition in invasive hVISA ST100 clinical strains isolated from the same patient (D1 and D2) before and after vancomycin treatment and two laboratory VISA mutants (D23C9 and D2P11) selected from D2 in independent experiments. High performance liquid chromatography-mass spectrometry (HPLC-MS) analysis of peptidoglycan muropeptides showed increased proportion of monomeric muropeptides and a concomitant decrease in the proportion of tetrameric muropeptide in D2 and derived mutants when compared to the original strain D1. In addition, strain D2 and its derived mutants showed an increase in cell wall thickness with increased pbp2 gene expression. The VISA phenotype was not stable in D2P11 and showed a reduced autolysis profile. On the other hand, the mutant D23C9 differentiates from D2 and D2P11 in the autolysis profile, and pbp4 transcription profile. D2-derived mutants exhibited differences in the susceptibility to other antimicrobials. Our results highlight the possibility of selection of different VISA phenotypes from a single hVISA-ST100 genetic background.
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Affiliation(s)
- Sabrina Di Gregorio
- 1 Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología y Biotecnología, Cátedra de Microbiología, Buenos Aires, Argentina
| | - Silvina Fernandez
- 1 Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología y Biotecnología, Cátedra de Microbiología, Buenos Aires, Argentina
| | - Arabela Cuirolo
- 2 Unité de Physiologie et génétique bactériennes, Département de Sciences de la vie, Centre d'Ingénierie des Protéines, Université de Liège , Liège, Belgique
| | - Olivier Verlaine
- 2 Unité de Physiologie et génétique bactériennes, Département de Sciences de la vie, Centre d'Ingénierie des Protéines, Université de Liège , Liège, Belgique
| | - Ana Amoroso
- 2 Unité de Physiologie et génétique bactériennes, Département de Sciences de la vie, Centre d'Ingénierie des Protéines, Université de Liège , Liège, Belgique
| | - Dominique Mengin-Lecreulx
- 3 Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, University Paris-Saclay, Gif-sur-Yvette, France
| | - Angela Famiglietti
- 4 Universidad de Buenos Aires, Hospital de Clínicas José de San Martín, Laboratorio de Bacteriología Clínica, Buenos Aires, Argentina
| | - Bernard Joris
- 2 Unité de Physiologie et génétique bactériennes, Département de Sciences de la vie, Centre d'Ingénierie des Protéines, Université de Liège , Liège, Belgique
| | - Marta Mollerach
- 1 Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología y Biotecnología, Cátedra de Microbiología, Buenos Aires, Argentina
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