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Xiong YQ, Li Y, Goncheva MI, Elsayed AM, Zhu F, Li L, Abdelhady W, Flannagan RS, Yeaman MR, Bayer AS, Heinrichs DE. The Purine Biosynthesis Repressor, PurR, Contributes to Vancomycin Susceptibility of Methicillin-resistant Staphylococcus aureus in Experimental Endocarditis. J Infect Dis 2024; 229:1648-1657. [PMID: 38297970 PMCID: PMC11175694 DOI: 10.1093/infdis/jiad577] [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: 07/27/2023] [Indexed: 02/02/2024] Open
Abstract
BACKGROUND Staphylococcus aureus is the most common cause of life-threatening endovascular infections, including infective endocarditis (IE). These infections, especially when caused by methicillin-resistant strains (MRSA), feature limited therapeutic options and high morbidity and mortality rates. METHODS Herein, we investigated the role of the purine biosynthesis repressor, PurR, in virulence factor expression and vancomycin (VAN) treatment outcomes in experimental IE due to MRSA. RESULTS The PurR-mediated repression of purine biosynthesis was confirmed by enhanced purF expression and production of an intermediate purine metabolite in purR mutant strain. In addition, enhanced expression of the transcriptional regulators, sigB and sarA, and their key downstream virulence genes (eg, fnbA, and hla) was demonstrated in the purR mutant in vitro and within infected cardiac vegetations. Furthermore, purR deficiency enhanced fnbA/fnbB transcription, translating to increased fibronectin adhesion versus the wild type and purR-complemented strains. Notably, the purR mutant was refractory to significant reduction in target tissues MRSA burden following VAN treatment in the IE model. CONCLUSIONS These findings suggest that the purine biosynthetic pathway intersects the coordination of virulence factor expression and in vivo persistence during VAN treatment, and may represent an avenue for novel antimicrobial development targeting MRSA.
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Affiliation(s)
- Yan Q Xiong
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
- Department of Medicine, Division of Infectious Diseases, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Yi Li
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
| | - Mariya I Goncheva
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Ahmed M Elsayed
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
| | - Fengli Zhu
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
| | - Liang Li
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
| | - Wessam Abdelhady
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
| | - Ronald S Flannagan
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Michael R Yeaman
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
- Department of Medicine, Division of Infectious Diseases, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
- Department of Medicine, Division of Molecular Medicine, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
| | - Arnold S Bayer
- The Lundquist Institute for Biomedical Innovation, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
- Department of Medicine, Division of Infectious Diseases, Harbor-University of California Los Angeles Medical Center, Torrance, California, USA
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - David E Heinrichs
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
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Kengmo Tchoupa A, Elsherbini AMA, Camus J, Fu X, Hu X, Ghaneme O, Seibert L, Lebtig M, Böcker MA, Horlbeck A, Lambidis SP, Schittek B, Kretschmer D, Lämmerhofer M, Peschel A. Lipase-mediated detoxification of host-derived antimicrobial fatty acids by Staphylococcus aureus. Commun Biol 2024; 7:572. [PMID: 38750133 PMCID: PMC11096360 DOI: 10.1038/s42003-024-06278-3] [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: 10/30/2023] [Accepted: 05/02/2024] [Indexed: 05/18/2024] Open
Abstract
Long-chain fatty acids with antimicrobial properties are abundant on the skin and mucosal surfaces, where they are essential to restrict the proliferation of opportunistic pathogens such as Staphylococcus aureus. These antimicrobial fatty acids (AFAs) elicit bacterial adaptation strategies, which have yet to be fully elucidated. Characterizing the pervasive mechanisms used by S. aureus to resist AFAs could open new avenues to prevent pathogen colonization. Here, we identify the S. aureus lipase Lip2 as a novel resistance factor against AFAs. Lip2 detoxifies AFAs via esterification with cholesterol. This is reminiscent of the activity of the fatty acid-modifying enzyme (FAME), whose identity has remained elusive for over three decades. In vitro, Lip2-dependent AFA-detoxification was apparent during planktonic growth and biofilm formation. Our genomic analysis revealed that prophage-mediated inactivation of Lip2 was rare in blood, nose, and skin strains, suggesting a particularly important role of Lip2 for host - microbe interactions. In a mouse model of S. aureus skin colonization, bacteria were protected from sapienic acid (a human-specific AFA) in a cholesterol- and lipase-dependent manner. These results suggest Lip2 is the long-sought FAME that exquisitely manipulates environmental lipids to promote bacterial growth in otherwise inhospitable niches.
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Affiliation(s)
- Arnaud Kengmo Tchoupa
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany.
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany.
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany.
| | - Ahmed M A Elsherbini
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Justine Camus
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Xiaoqing Fu
- Institute of Pharmaceutical Sciences, University of Tübingen, Tübingen, Germany
| | - Xuanheng Hu
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Oumayma Ghaneme
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Lea Seibert
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Marco Lebtig
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Marieke A Böcker
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Anima Horlbeck
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Stilianos P Lambidis
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Birgit Schittek
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- Dermatology Department, University Hospital Tübingen, Tübingen, Germany
| | - Dorothee Kretschmer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Michael Lämmerhofer
- Institute of Pharmaceutical Sciences, University of Tübingen, Tübingen, Germany
| | - Andreas Peschel
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology Section, University of Tübingen, Tübingen, Germany
- Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
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Habib G, Gul H, Ahmad P, Hayat A, Rehman MU, Mohamed Moussa I, Elansary HO. Teicoplanin associated gene tcaA inactivation increases persister cell formation in Staphylococcus aureus. Front Microbiol 2023; 14:1241995. [PMID: 37901830 PMCID: PMC10611510 DOI: 10.3389/fmicb.2023.1241995] [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: 06/18/2023] [Accepted: 09/25/2023] [Indexed: 10/31/2023] Open
Abstract
Staphylococcus aureus is part of normal human flora and is widely associated with hospital-acquired bacteremia. S. aureus has shown a diverse array of resistance to environmental stresses and antibiotics. Methicillin-resistant S. aureus (MRSA) is on the high priority list of new antibiotics discovery and glycopeptides are considered the last drug of choice against MRSA. S. aureus has developed resistance against glycopeptides and the emergence of vancomycin-intermediate-resistant, vancomycin-resistant, and teicoplanin-resistant strains is globally reported. Teicoplanin-associated genes tcaR-tcaA-tcaB (tcaRAB) is known as the S. aureus glycopeptide resistance operon that is associated with glycopeptide resistance. Here, for the first time, the role of tcaRAB in S. aureus persister cells formation, and ΔtcaA dependent persisters' ability to resuscitate the bacterial population was explored. We recovered a clinical strain of MRSA from a COVID-19 patient which showed a high level of resistance to teicoplanin, vancomycin, and methicillin. Whole genome RNA sequencing revealed that the tcaRAB operon expression was altered followed by high expression of glyS and sgtB. The RNA-seq data revealed a significant decrease in tcaA (p = 0.008) and tcaB (p = 0.04) expression while tcaR was not significantly altered. We knocked down tcaA, tcaB, and tcaR using CRISPR-dCas9 and the results showed that when tcaA was suppressed by dCas9, a significant increase was witnessed in persister cells while tcaB suppression did not induce persistence. The results were further evaluated by creating a tcaA mutant that showed ΔtcaA formed a significant increase in persisters in comparison to the wild type. Based on our findings, we concluded that tcaA is the gene that increases persister cells and glycopeptide resistance and could be a potential therapeutic target in S. aureus.
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Affiliation(s)
- Gul Habib
- Department of Microbiology, Abbottabad University of Science and Technology, Abbottabad, Pakistan
| | - Haji Gul
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, China
- Faculty of Veterinary and Animal Sciences, Gomal University, Dera Ismail Khan, Pakistan
| | - Prevez Ahmad
- Department of Physics, University of Azad Jammu and Kashmir, Muzaffarabad, Pakistan
| | - Azam Hayat
- Department of Microbiology, Abbottabad University of Science and Technology, Abbottabad, Pakistan
| | - Mujaddad Ur Rehman
- Department of Microbiology, Abbottabad University of Science and Technology, Abbottabad, Pakistan
| | - Ihab Mohamed Moussa
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Hosam O. Elansary
- Plant Production Department, College of Food & Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
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4
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Costa MDOCE, do Nascimento APB, Martins YC, dos Santos MT, Figueiredo AMDS, Perez-Rueda E, Nicolás MF. The gene regulatory network of Staphylococcus aureus ST239-SCC mecIII strain Bmb9393 and assessment of genes associated with the biofilm in diverse backgrounds. Front Microbiol 2023; 13:1049819. [PMID: 36704545 PMCID: PMC9871828 DOI: 10.3389/fmicb.2022.1049819] [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: 09/21/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023] Open
Abstract
Introduction Staphylococcus aureus is one of the most prevalent and relevant pathogens responsible for a wide spectrum of hospital-associated or community-acquired infections. In addition, methicillin-resistant Staphylococcus aureus may display multidrug resistance profiles that complicate treatment and increase the mortality rate. The ability to produce biofilm, particularly in device-associated infections, promotes chronic and potentially more severe infections originating from the primary site. Understanding the complex mechanisms involved in planktonic and biofilm growth is critical to identifying regulatory connections and ways to overcome the global health problem of multidrug-resistant bacteria. Methods In this work, we apply literature-based and comparative genomics approaches to reconstruct the gene regulatory network of the high biofilm-producing strain Bmb9393, belonging to one of the highly disseminating successful clones, the Brazilian epidemic clone. To the best of our knowledge, we describe for the first time the topological properties and network motifs for the Staphylococcus aureus pathogen. We performed this analysis using the ST239-SCCmecIII Bmb9393 strain. In addition, we analyzed transcriptomes available in the literature to construct a set of genes differentially expressed in the biofilm, covering different stages of the biofilms and genetic backgrounds of the strains. Results and discussion The Bmb9393 gene regulatory network comprises 1,803 regulatory interactions between 64 transcription factors and the non-redundant set of 1,151 target genes with the inclusion of 19 new regulons compared to the N315 transcriptional regulatory network published in 2011. In the Bmb9393 network, we found 54 feed-forward loop motifs, where the most prevalent were coherent type 2 and incoherent type 2. The non-redundant set of differentially expressed genes in the biofilm consisted of 1,794 genes with functional categories relevant for adaptation to the variable microenvironments established throughout the biofilm formation process. Finally, we mapped the set of genes with altered expression in the biofilm in the Bmb9393 gene regulatory network to depict how different growth modes can alter the regulatory systems. The data revealed 45 transcription factors and 876 shared target genes. Thus, the gene regulatory network model provided represents the most up-to-date model for Staphylococcus aureus, and the set of genes altered in the biofilm provides a global view of their influence on biofilm formation from distinct experimental perspectives and different strain backgrounds.
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Affiliation(s)
| | - Ana Paula Barbosa do Nascimento
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo, Brazil
| | | | | | - Agnes Marie de Sá Figueiredo
- Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, Unidad Académica Yucatán, Merida, Mexico
| | - Ernesto Perez-Rueda
- Laboratório de Biologia Molecular de Bactérias, Instituto de Microbiologia Paulo de Goés, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil,*Correspondence: Ernesto Perez-Rueda ✉
| | - Marisa Fabiana Nicolás
- Laboratório Nacional de Computação Científica (LNCC), Petrópolis, Brazil,Marisa Fabiana Nicolás ✉
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5
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Sun L, Zhang H, Zhang H, Lou X, Wang Z, Wu Y, Yang X, Chen D, Guo B, Zhang A, Qian F. Staphylococcal virulence factor HlgB targets the endoplasmic-reticulum-resident E3 ubiquitin ligase AMFR to promote pneumonia. Nat Microbiol 2023; 8:107-120. [PMID: 36593296 DOI: 10.1038/s41564-022-01278-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 10/21/2022] [Indexed: 01/03/2023]
Abstract
Staphylococcus aureus invades cells and persists intracellularly, causing persistent inflammation that is notoriously difficult to treat. Here we investigated host-pathogen interactions underlying intracellular S. aureus infection in macrophages and discovered that the endoplasmic reticulum (ER) is an important cellular compartment for intracellular S. aureus infection. Using CRISPR-Cas9 guide RNA library screening, we determined that the autocrine motility factor receptor (AMFR), an ER-resident E3 ubiquitin ligase, played an essential role in mediating intracellular S. aureus-induced inflammation. AMFR directly interacted with TAK1-binding protein 3 (TAB3) in the ER, inducing K27-linked polyubiquitination of TAB3 on lysine 649 and promoting TAK1 activation. Moreover, the virulence factor γ-haemolysin B (HIgB) of S. aureus bound to the AMFR and regulated TAB3. Our findings highlight an unknown role of AMFR in intracellular S. aureus infection-induced pneumonia and suggest that pharmacological interruption of AMFR-mediated TAB3 signalling cascades and HIgB targeting may prevent invasive staphylococci-mediated pneumonia.
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Affiliation(s)
- Lei Sun
- Engineering Research Center of Cell & Therapeutic Antibody, Ministry of Education, Pharm-X Center, Research Center for Small Molecule Immunological Drugs, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China.
| | - Haibo Zhang
- Engineering Research Center of Cell & Therapeutic Antibody, Ministry of Education, Pharm-X Center, Research Center for Small Molecule Immunological Drugs, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Huihui Zhang
- Engineering Research Center of Cell & Therapeutic Antibody, Ministry of Education, Pharm-X Center, Research Center for Small Molecule Immunological Drugs, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Xinyi Lou
- Engineering Research Center of Cell & Therapeutic Antibody, Ministry of Education, Pharm-X Center, Research Center for Small Molecule Immunological Drugs, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Zhiming Wang
- Engineering Research Center of Cell & Therapeutic Antibody, Ministry of Education, Pharm-X Center, Research Center for Small Molecule Immunological Drugs, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Yaxian Wu
- Department of Basic Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Xinyi Yang
- Engineering Research Center of Cell & Therapeutic Antibody, Ministry of Education, Pharm-X Center, Research Center for Small Molecule Immunological Drugs, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Daijie Chen
- Engineering Research Center of Cell & Therapeutic Antibody, Ministry of Education, Pharm-X Center, Research Center for Small Molecule Immunological Drugs, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Beining Guo
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Ao Zhang
- Engineering Research Center of Cell & Therapeutic Antibody, Ministry of Education, Pharm-X Center, Research Center for Small Molecule Immunological Drugs, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Feng Qian
- Engineering Research Center of Cell & Therapeutic Antibody, Ministry of Education, Pharm-X Center, Research Center for Small Molecule Immunological Drugs, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China.
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6
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Mangu JCK, Stylianou M, Olsson PE, Jass J. Per- and polyfluoroalkyl substances enhance Staphylococcus aureus pathogenicity and impair host immune response. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 314:120294. [PMID: 36181932 DOI: 10.1016/j.envpol.2022.120294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 09/18/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Per- and Poly-fluoroalkyl substances (PFAS) are major persistent environmental contaminants. Epidemiological studies have linked PFAS exposures to altered immunity and increased occurrence of infections in children. However, the mechanisms leading to immune susceptibility to bacterial infections remains unclear. To elucidate the mechanism, transcriptional alteration in the Caenorhabditis elegans model caused by a PFAS contaminated environmental water and two reconstituted PFAS solutions were evaluated using RNA-sequencing. PFAS affected the expression of several genes involved in C. elegans immune surveillance to Gram-positive bacteria (cpr-2, tag-38, spp-1, spp-5, clec-7, clec-172). The combined exposure to PFAS and Staphylococcus aureus significantly reduced C. elegans survival and increased intestinal membrane permeability. Furthermore, the growth of S. aureus in the presence of PFAS increased the expression of virulence genes, specifically, the virulence gene regulator saeR and α-hemolysin, hla, which resulted in increased hemolytic activity. The present study demonstrated that PFAS exposure not only increased C. elegans susceptibility to pathogens by reducing host immunity and increasing intestinal membrane permeability, but also increased bacteria virulence. This presents a broader implication for humans and other animals, where environmental contaminants simultaneously reduce host resilience, while, increasing microbial pathogenicity.
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Affiliation(s)
| | - Marios Stylianou
- The Life Science Centre-Biology, School of Science and Technology, Örebro University, Örebro, Sweden
| | - Per-Erik Olsson
- The Life Science Centre-Biology, School of Science and Technology, Örebro University, Örebro, Sweden
| | - Jana Jass
- The Life Science Centre-Biology, School of Science and Technology, Örebro University, Örebro, Sweden.
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7
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Sionov RV, Banerjee S, Bogomolov S, Smoum R, Mechoulam R, Steinberg D. Targeting the Achilles’ Heel of Multidrug-Resistant Staphylococcus aureus by the Endocannabinoid Anandamide. Int J Mol Sci 2022; 23:ijms23147798. [PMID: 35887146 PMCID: PMC9319909 DOI: 10.3390/ijms23147798] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/10/2022] [Accepted: 07/12/2022] [Indexed: 02/06/2023] Open
Abstract
Antibiotic-resistant Staphylococcus aureus is a major health issue that requires new therapeutic approaches. Accumulating data suggest that it is possible to sensitize these bacteria to antibiotics by combining them with inhibitors targeting efflux pumps, the low-affinity penicillin-binding protein PBP2a, cell wall teichoic acid, or the cell division protein FtsZ. We have previously shown that the endocannabinoid Anandamide (N-arachidonoylethanolamine; AEA) could sensitize drug-resistant S. aureus to a variety of antibiotics, among others, through growth arrest and inhibition of drug efflux. Here, we looked at biochemical alterations caused by AEA. We observed that AEA increased the intracellular drug concentration of a fluorescent penicillin and augmented its binding to membrane proteins with concomitant altered membrane distribution of these proteins. AEA also prevented the secretion of exopolysaccharides (EPS) and reduced the cell wall teichoic acid content, both processes known to require transporter proteins. Notably, AEA was found to inhibit membrane ATPase activity that is necessary for transmembrane transport. AEA did not affect the membrane GTPase activity, and the GTPase cell division protein FtsZ formed the Z-ring of the divisome normally in the presence of AEA. Rather, AEA caused a reduction in murein hydrolase activities involved in daughter cell separation. Altogether, this study shows that AEA affects several biochemical processes that culminate in the sensitization of the drug-resistant bacteria to antibiotics.
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Affiliation(s)
- Ronit Vogt Sionov
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
- Correspondence:
| | - Shreya Banerjee
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
| | - Sergei Bogomolov
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
| | - Reem Smoum
- Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (R.S.); (R.M.)
| | - Raphael Mechoulam
- Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (R.S.); (R.M.)
| | - Doron Steinberg
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
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8
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Abstract
The type VII protein secretion system (T7SS) of Staphylococcus aureus is encoded at the ess locus. T7 substrate recognition and protein transport are mediated by EssC, a membrane-bound multidomain ATPase. Four EssC sequence variants have been identified across S. aureus strains, each accompanied by a specific suite of substrate proteins. The ess genes are upregulated during persistent infection, and the secretion system contributes to virulence in disease models. It also plays a key role in intraspecies competition, secreting nuclease and membrane-depolarizing toxins that inhibit the growth of strains lacking neutralizing immunity proteins. A genomic survey indicates that the T7SS is widely conserved across staphylococci and is encoded in clusters that contain diverse arrays of toxin and immunity genes. The presence of genomic islands encoding multiple immunity proteins in species such as Staphylococcus warneri that lack the T7SS points to a major role for the secretion system in bacterial antagonism. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Lisa Bowman
- Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom; ,
| | - Tracy Palmer
- Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom; ,
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9
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Kengmo Tchoupa A, Eijkelkamp BA, Peschel A. Bacterial adaptation strategies to host-derived fatty acids. Trends Microbiol 2021; 30:241-253. [PMID: 34218980 DOI: 10.1016/j.tim.2021.06.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/06/2021] [Accepted: 06/07/2021] [Indexed: 01/08/2023]
Abstract
Fatty acids (FAs) are potent antimicrobials which hold great promise as viable alternatives or complements to conventional antibiotics. Intriguingly, bacteria are well equipped to use environmental FAs as energy sources and/or building blocks for their membrane lipids. Furthermore, these microbes display a wide array of mechanisms to prevent or mitigate FA toxicity. In this review we discuss strategies that bacteria use to thrive despite extensive exposure to host-derived antimicrobial FAs. We also highlight the altered response of these FA-adapted bacteria to antibiotics. Given the ubiquitous nature of FAs in various host environments, deciphering bacterial adaptation strategies to FAs is of prime importance. This knowledge may pave the way for a rational design of FA-based combination therapies with antibiotics.
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Affiliation(s)
- Arnaud Kengmo Tchoupa
- Department of Infection Biology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany; Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Tübingen, Germany.
| | - Bart A Eijkelkamp
- Molecular Sciences and Technology, College of Science and Engineering, Flinders University, Adelaide, Australia
| | - Andreas Peschel
- Department of Infection Biology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Tübingen, Germany; Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Tübingen, Germany
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10
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Chatterjee A, Willett JLE, Dunny GM, Duerkop BA. Phage infection and sub-lethal antibiotic exposure mediate Enterococcus faecalis type VII secretion system dependent inhibition of bystander bacteria. PLoS Genet 2021; 17:e1009204. [PMID: 33411815 PMCID: PMC7790226 DOI: 10.1371/journal.pgen.1009204] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 10/08/2020] [Indexed: 02/07/2023] Open
Abstract
Bacteriophages (phages) are being considered as alternative therapeutics for the treatment of multidrug resistant bacterial infections. Considering phages have narrow host-ranges, it is generally accepted that therapeutic phages will have a marginal impact on non-target bacteria. We have discovered that lytic phage infection induces transcription of type VIIb secretion system (T7SS) genes in the pathobiont Enterococcus faecalis. Membrane damage during phage infection induces T7SS gene expression resulting in cell contact dependent antagonism of different Gram positive bystander bacteria. Deletion of essB, a T7SS structural component, abrogates phage-mediated killing of bystanders. A predicted immunity gene confers protection against T7SS mediated inhibition, and disruption of its upstream LXG toxin gene rescues growth of E. faecalis and Staphylococcus aureus bystanders. Phage induction of T7SS gene expression and bystander inhibition requires IreK, a serine/threonine kinase, and OG1RF_11099, a predicted GntR-family transcription factor. Additionally, sub-lethal doses of membrane targeting and DNA damaging antibiotics activated T7SS expression independent of phage infection, triggering T7SS antibacterial activity against bystander bacteria. Our findings highlight how phage infection and antibiotic exposure of a target bacterium can affect non-target bystander bacteria and implies that therapies beyond antibiotics, such as phage therapy, could impose collateral damage to polymicrobial communities. Renewed interest in phages as alternative therapeutics to combat multi-drug resistant bacterial infections, highlights the importance of understanding the consequences of phage-bacteria interactions in the context of microbial communities. Although it is well established that phages are highly specific for their host bacterium, there is no clear consensus on whether or not phage infection (and thus phage therapy) would impose collateral damage to non-target bacteria in polymicrobial communities. Here we provide direct evidence of how phage infection of a clinically relevant pathogen triggers an intrinsic type VII secretion system (T7SS) antibacterial response that consequently restricts the growth of neighboring bacterial cells that are not susceptible to phage infection. Phage induction of T7SS activity is a stress response and in addition to phages, T7SS antagonism can be induced using sub-inhibitory concentrations of antibiotics that facilitate membrane or DNA damage. Together these data show that a bacterial pathogen responds to diverse stressors to induce T7SS activity which manifests through the antagonism of neighboring non-kin bystander bacterial cells.
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Affiliation(s)
- Anushila Chatterjee
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States of America
| | - Julia L. E. Willett
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, United States of America
| | - Gary M. Dunny
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, United States of America
| | - Breck A. Duerkop
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States of America
- * E-mail:
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11
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Alhajjar N, Chatterjee A, Spencer BL, Burcham LR, Willett JLE, Dunny GM, Duerkop BA, Doran KS. Genome-Wide Mutagenesis Identifies Factors Involved in Enterococcus faecalis Vaginal Adherence and Persistence. Infect Immun 2020; 88:e00270-20. [PMID: 32778611 PMCID: PMC7504943 DOI: 10.1128/iai.00270-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/26/2020] [Indexed: 02/08/2023] Open
Abstract
Enterococcus faecalis is a Gram-positive commensal bacterium native to the gastrointestinal tract and an opportunistic pathogen of increasing clinical concern. E. faecalis also colonizes the female reproductive tract, and reports suggest vaginal colonization increases following antibiotic treatment or in patients with aerobic vaginitis. Currently, little is known about specific factors that promote E. faecalis vaginal colonization and subsequent infection. We modified an established mouse vaginal colonization model to explore E. faecalis vaginal carriage and demonstrate that both vancomycin-resistant and -sensitive strains colonize the murine vaginal tract. Following vaginal colonization, we observed E. faecalis in vaginal, cervical, and uterine tissue. A mutant lacking endocarditis- and biofilm-associated pili (Ebp) exhibited a decreased ability to associate with human vaginal and cervical cells in vitro but did not contribute to colonization in vivo Thus, we screened a low-complexity transposon (Tn) mutant library to identify novel genes important for E. faecalis colonization and persistence in the vaginal tract. This screen revealed 383 mutants that were underrepresented during vaginal colonization at 1, 5, and 8 days postinoculation compared to growth in culture medium. We confirmed that mutants deficient in ethanolamine catabolism or in the type VII secretion system were attenuated in persisting during vaginal colonization. These results reveal the complex nature of vaginal colonization and suggest that multiple factors contribute to E. faecalis persistence in the reproductive tract.
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Affiliation(s)
- Norhan Alhajjar
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Anushila Chatterjee
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Brady L Spencer
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Lindsey R Burcham
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Julia L E Willett
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Gary M Dunny
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Breck A Duerkop
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
| | - Kelly S Doran
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado, USA
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12
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The type VII secretion system protects Staphylococcus aureus against antimicrobial host fatty acids. Sci Rep 2020; 10:14838. [PMID: 32908165 PMCID: PMC7481793 DOI: 10.1038/s41598-020-71653-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/17/2020] [Indexed: 02/06/2023] Open
Abstract
The Staphylococcus aureus type VII secretion system (T7SS) exports several proteins that are pivotal for bacterial virulence. The mechanisms underlying T7SS-mediated staphylococcal survival during infection nevertheless remain unclear. Here we report that S. aureus lacking T7SS components are more susceptible to host-derived antimicrobial fatty acids. Unsaturated fatty acids such as linoleic acid (LA) elicited an increased inhibition of S. aureus mutants lacking T7SS effectors EsxC, EsxA and EsxB, or the membrane-bound ATPase EssC, compared to the wild-type (WT). T7SS mutants generated in different S. aureus strain backgrounds also displayed an increased sensitivity to LA. Analysis of bacterial membrane lipid profiles revealed that the esxC mutant was less able to incorporate LA into its membrane phospholipids. Although the ability to bind labelled LA did not differ between the WT and mutant strains, LA induced more cell membrane damage in the T7SS mutants compared to the WT. Furthermore, proteomic analyses of WT and mutant cell fractions revealed that, in addition to compromising membranes, T7SS defects induce oxidative stress and hamper their response to LA challenge. Thus, our findings indicate that T7SS contribute to maintaining S. aureus membrane integrity and homeostasis when bacteria encounter antimicrobial fatty acids.
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13
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Allergy-A New Role for T Cell Superantigens of Staphylococcus aureus? Toxins (Basel) 2020; 12:toxins12030176. [PMID: 32178378 PMCID: PMC7150838 DOI: 10.3390/toxins12030176] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 03/06/2020] [Accepted: 03/10/2020] [Indexed: 12/16/2022] Open
Abstract
Staphylococcus aureus superantigens (SAgs) are among the most potent T cell mitogens known. They stimulate large fractions of T cells by cross-linking their T cell receptor with major histocompatibility complex class-II molecules on antigen presenting cells, resulting in T cell proliferation and massive cytokine release. To date, 26 different SAgs have been described in the species S. aureus; they comprise the toxic shock syndrome toxin (TSST-1), as well as 25 staphylococcal enterotoxins (SEs) or enterotoxin-like proteins (SEls). SAgs can cause staphylococcal food poisoning and toxic shock syndrome and contribute to the clinical symptoms of staphylococcal infection. In addition, there is growing evidence that SAgs are involved in allergic diseases. This review provides an overview on recent epidemiological data on the involvement of S. aureus SAgs and anti-SAg-IgE in allergy, demonstrating that being sensitized to SEs—in contrast to inhalant allergens—is associated with a severe disease course in patients with chronic airway inflammation. The mechanisms by which SAgs trigger or amplify allergic immune responses, however, are not yet fully understood. Here, we discuss known and hypothetical pathways by which SAgs can drive an atopic disease.
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14
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Abstract
Staphylococcus aureus is a Gram-positive opportunistic pathogen that has evolved a complex regulatory network to control virulence. One of the main functions of this interconnected network is to sense various environmental cues and respond by altering the production of virulence factors necessary for survival in the host, including cell surface adhesins and extracellular enzymes and toxins. Of these S. aureus regulatory systems, one of the best studied is the accessory gene regulator (agr), which is a quorum-sensing system that senses the local concentration of a cyclic peptide signaling molecule. This system allows S. aureus to sense its own population density and translate this information into a specific gene expression pattern. Besides agr, this pathogen uses other two-component systems to sense specific cues and coordinates responses with cytoplasmic regulators of the SarA protein family and alternative sigma factors. These divergent regulatory systems integrate the various environmental and host-derived signals into a network that ensures optimal pathogen response to the changing conditions. This article gives an overview of the most important and best-studied S. aureus regulatory systems and summarizes the functions of these regulators during host interactions. The regulatory systems discussed include the agr quorum-sensing system; the SaeRS, SrrAB, and ArlRS two-component systems, the cytoplasmic SarA-family regulators (SarA, Rot, and MgrA); and the alternative sigma factors (SigB and SigH).
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15
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Pulmonary Surfactant Promotes Virulence Gene Expression and Biofilm Formation in Klebsiella pneumoniae. Infect Immun 2018; 86:IAI.00135-18. [PMID: 29712730 DOI: 10.1128/iai.00135-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 04/24/2018] [Indexed: 12/18/2022] Open
Abstract
The interactions between Klebsiella pneumoniae and the host environment at the site of infection are largely unknown. Pulmonary surfactant serves as an initial point of contact for inhaled bacteria entering the lung and is thought to contain molecular cues that aid colonization and pathogenesis. To gain insight into this ecological transition, we characterized the transcriptional response of K. pneumoniae MGH 78578 to purified pulmonary surfactant. This work revealed changes within the K. pneumoniae transcriptome that likely contribute to host colonization, adaptation, and virulence in vivo Notable transcripts expressed under these conditions include genes involved in capsule synthesis, lipopolysaccharide modification, antibiotic resistance, biofilm formation, and metabolism. In addition, we tested the contributions of other surfactant-induced transcripts to K. pneumoniae survival using engineered isogenic KPPR1 deletion strains in a murine model of acute pneumonia. In these infection studies, we identified the MdtJI polyamine efflux pump and the ProU glycine betaine ABC transporter to be significant mediators of K. pneumoniae survival within the lung and confirmed previous evidence for the importance of de novo leucine synthesis to bacterial survival during infection. Finally, we determined that pulmonary surfactant promoted type 3 fimbria-mediated biofilm formation in K. pneumoniae and identified two surfactant constituents, phosphatidylcholine and cholesterol, that drive this response. This study provides novel insight into the interactions occurring between K. pneumoniae and the host at an important infection site and demonstrates the utility of purified lung surfactant preparations for dissecting host-lung pathogen interactions in vitro.
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16
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Rouha H, Weber S, Janesch P, Maierhofer B, Gross K, Dolezilkova I, Mirkina I, Visram ZC, Malafa S, Stulik L, Badarau A, Nagy E. Disarming Staphylococcus aureus from destroying human cells by simultaneously neutralizing six cytotoxins with two human monoclonal antibodies. Virulence 2017; 9:231-247. [PMID: 29099326 PMCID: PMC5955178 DOI: 10.1080/21505594.2017.1391447] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Pathogenesis of Staphylococcus aureus is increasingly recognized to be driven by powerful toxins. Staphylococcus aureus employs up to six pore-forming toxins to subvert the human host defense and to promote bacterial invasion: alpha-hemolysin that disrupts epithelial and endothelial barriers and five leukocidins that lyse phagocytes involved in bacterial clearance. Previously, we described two human monoclonal antibodies (mAbs), ASN-1 that neutralizes alpha-hemolysin and four leukocidins (LukSF-PV, LukED, HlgAB, HlgCB), and ASN-2 that inactivates the 5th leukocidin, LukGH. In this study we tested the individual and combined effects of ASN-1 and ASN-2 in multiple in vitro models employing relevant human target cells. We found that diverse S. aureus isolates with different genetic backgrounds (based on MLST- and spa-typing) and antibiotic sensitivity (both MRSA and MSSA) displayed greatly different cytotoxin expression patterns influenced by the type of growth medium used. Both mAbs were required to fully prevent the lysis of human neutrophils exposed to the mixture of recombinant cytotoxins or native toxins present in the culture supernatants of S. aureus isolates. Flow cytometry confirmed the protective effects of ASN-1 + ASN-2 (known as ASN100) on granulocytes, monocytes, NK-cells and T-lymphocytes. ASN-1 alone preserved the integrity of a 3D-primary culture of human tracheal/bronchial mucociliary epithelial tissue infected with S. aureus. We conclude that simultaneous inhibition of alpha-hemolysin and five leukocidins by ASN100 blocks cytolytic activity of S. aureus towards human target cells in vitro.
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Affiliation(s)
- Harald Rouha
- a Arsanis Biosciences, Helmut-Qualtinger-Gasse 2, Campus Vienna Biocenter , Vienna , Austria
| | - Susanne Weber
- a Arsanis Biosciences, Helmut-Qualtinger-Gasse 2, Campus Vienna Biocenter , Vienna , Austria
| | - Philipp Janesch
- a Arsanis Biosciences, Helmut-Qualtinger-Gasse 2, Campus Vienna Biocenter , Vienna , Austria
| | - Barbara Maierhofer
- a Arsanis Biosciences, Helmut-Qualtinger-Gasse 2, Campus Vienna Biocenter , Vienna , Austria
| | - Karin Gross
- a Arsanis Biosciences, Helmut-Qualtinger-Gasse 2, Campus Vienna Biocenter , Vienna , Austria
| | - Ivana Dolezilkova
- a Arsanis Biosciences, Helmut-Qualtinger-Gasse 2, Campus Vienna Biocenter , Vienna , Austria
| | - Irina Mirkina
- a Arsanis Biosciences, Helmut-Qualtinger-Gasse 2, Campus Vienna Biocenter , Vienna , Austria
| | - Zehra C Visram
- a Arsanis Biosciences, Helmut-Qualtinger-Gasse 2, Campus Vienna Biocenter , Vienna , Austria
| | - Stefan Malafa
- a Arsanis Biosciences, Helmut-Qualtinger-Gasse 2, Campus Vienna Biocenter , Vienna , Austria
| | - Lukas Stulik
- a Arsanis Biosciences, Helmut-Qualtinger-Gasse 2, Campus Vienna Biocenter , Vienna , Austria
| | - Adriana Badarau
- a Arsanis Biosciences, Helmut-Qualtinger-Gasse 2, Campus Vienna Biocenter , Vienna , Austria
| | - Eszter Nagy
- a Arsanis Biosciences, Helmut-Qualtinger-Gasse 2, Campus Vienna Biocenter , Vienna , Austria
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17
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Carrera M, Böhme K, Gallardo JM, Barros-Velázquez J, Cañas B, Calo-Mata P. Characterization of Foodborne Strains of Staphylococcus aureus by Shotgun Proteomics: Functional Networks, Virulence Factors and Species-Specific Peptide Biomarkers. Front Microbiol 2017; 8:2458. [PMID: 29312172 PMCID: PMC5732212 DOI: 10.3389/fmicb.2017.02458] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/27/2017] [Indexed: 11/13/2022] Open
Abstract
In the present work, we applied a shotgun proteomics approach for the fast and easy characterization of 20 different foodborne strains of Staphylococcus aureus (S. aureus), one of the most recognized foodborne pathogenic bacteria. A total of 644 non-redundant proteins were identified and analyzed via an easy and rapid protein sample preparation procedure. The results allowed the differentiation of several proteome datasets from the different strains (common, accessory, and unique datasets), which were used to determine relevant functional pathways and differentiate the strains into different Euclidean hierarchical clusters. Moreover, a predicted protein-protein interaction network of the foodborne S. aureus strains was created. The whole confidence network contains 77 nodes and 769 interactions. Most of the identified proteins were surface-associated proteins that were related to pathways and networks of energy, lipid metabolism and virulence. Twenty-seven virulence factors were identified, and most of them corresponded to autolysins, N-acetylmuramoyl-L-alanine amidases, phenol-soluble modulins, extracellular fibrinogen-binding proteins and virulence factor EsxA. Potential species-specific peptide biomarkers were screened. Twenty-one species-specific peptide biomarkers, belonging to eight different proteins (nickel-ABC transporter, N-acetylmuramoyl-L-alanine amidase, autolysin, clumping factor A, gram-positive signal peptide YSIRK, cysteine protease/staphopain, transcriptional regulator MarR, and transcriptional regulator Sar-A), were proposed to identify S. aureus. These results constitute the first major dataset of peptides and proteins of foodborne S. aureus strains. This repository may be useful for further studies, for the development of new therapeutic treatments for S. aureus food intoxications and for microbial source-tracking in foodstuffs.
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Affiliation(s)
- Mónica Carrera
- Department of Food Technology, Spanish National Research Council, Marine Research Institute, Vigo, Spain
| | - Karola Böhme
- Department of Analytical Chemistry, Nutrition and Food Science, School of Veterinary Sciences, University of Santiago de Compostela, Lugo, Spain
| | - José M. Gallardo
- Department of Food Technology, Spanish National Research Council, Marine Research Institute, Vigo, Spain
| | - Jorge Barros-Velázquez
- Department of Analytical Chemistry, Nutrition and Food Science, School of Veterinary Sciences, University of Santiago de Compostela, Lugo, Spain
| | - Benito Cañas
- Department of Analytical Chemistry, Complutense University of Madrid, Madrid, Spain
| | - Pilar Calo-Mata
- Department of Analytical Chemistry, Nutrition and Food Science, School of Veterinary Sciences, University of Santiago de Compostela, Lugo, Spain
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18
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Casabona MG, Kneuper H, Alferes de Lima D, Harkins CP, Zoltner M, Hjerde E, Holden MTG, Palmer T. Haem-iron plays a key role in the regulation of the Ess/type VII secretion system of Staphylococcus aureus RN6390. MICROBIOLOGY-SGM 2017; 163:1839-1850. [PMID: 29171824 PMCID: PMC5845736 DOI: 10.1099/mic.0.000579] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The Staphylococcus aureus type VII protein secretion system (T7SS) plays important roles in virulence and intra-species competition. Here we show that the T7SS in strain RN6390 is activated by supplementing the growth medium with haemoglobin, and its cofactor haemin (haem B). Transcript analysis and secretion assays suggest that activation by haemin occurs at a transcriptional and a post-translational level. Loss of T7 secretion activity by deletion of essC results in upregulation of genes required for iron acquisition. Taken together these findings suggest that the T7SS plays a role in iron homeostasis in at least some S. aureus strains.
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Affiliation(s)
- M Guillermina Casabona
- Division of Molecular Microbiology School of Life Sciences, University of Dundee, Dundee, UK
| | - Holger Kneuper
- Division of Molecular Microbiology School of Life Sciences, University of Dundee, Dundee, UK
| | - Daniela Alferes de Lima
- Division of Molecular Microbiology School of Life Sciences, University of Dundee, Dundee, UK
| | | | - Martin Zoltner
- Division of Molecular Microbiology School of Life Sciences, University of Dundee, Dundee, UK
| | - Erik Hjerde
- Department of Chemistry, Arctic University of Norway, Tromsø, Norway
| | | | - Tracy Palmer
- Division of Molecular Microbiology School of Life Sciences, University of Dundee, Dundee, UK
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19
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Host-derived fatty acids activate type VII secretion in Staphylococcus aureus. Proc Natl Acad Sci U S A 2017; 114:11223-11228. [PMID: 28973946 DOI: 10.1073/pnas.1700627114] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The type VII secretion system (T7SS) of Staphylococcus aureus is a multiprotein complex dedicated to the export of several virulence factors during host infection. This virulence pathway plays a key role in promoting bacterial survival and the long-term persistence of staphylococcal abscess communities. The expression of the T7SS is activated by bacterial interaction with host tissues including blood serum, nasal secretions, and pulmonary surfactant. In this work we identify the major stimulatory factors as host-specific cis-unsaturated fatty acids. Increased T7SS expression requires host fatty acid incorporation into bacterial biosynthetic pathways by the Saureus fatty acid kinase (FAK) complex, and FakA is required for virulence. The incorporated cis-unsaturated fatty acids decrease Saureus membrane fluidity, and these altered membrane dynamics are partially responsible for T7SS activation. These data define a molecular mechanism by which Saureus cells sense the host environment and implement appropriate virulence pathways.
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20
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Abstract
The staphylococci comprise a diverse genus of Gram-positive, nonmotile commensal organisms that inhabit the skin and mucous membranes of humans and other mammals. In general, staphylococci are benign members of the natural flora, but many species have the capacity to be opportunistic pathogens, mainly infecting individuals who have medical device implants or are otherwise immunocompromised. Staphylococcus aureus and Staphylococcus epidermidis are major sources of hospital-acquired infections and are the most common causes of surgical site infections and medical device-associated bloodstream infections. The ability of staphylococci to form biofilms in vivo makes them highly resistant to chemotherapeutics and leads to chronic diseases. These biofilm infections include osteomyelitis, endocarditis, medical device infections, and persistence in the cystic fibrosis lung. Here, we provide a comprehensive analysis of our current understanding of staphylococcal biofilm formation, with an emphasis on adhesins and regulation, while also addressing how staphylococcal biofilms interact with the immune system. On the whole, this review will provide a thorough picture of biofilm formation of the staphylococcus genus and how this mode of growth impacts the host.
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21
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Shao B, Liu Z, Zhong H, Zeng G, Liu G, Yu M, Liu Y, Yang X, Li Z, Fang Z, Zhang J, Zhao C. Effects of rhamnolipids on microorganism characteristics and applications in composting: A review. Microbiol Res 2017; 200:33-44. [PMID: 28527762 DOI: 10.1016/j.micres.2017.04.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 04/01/2017] [Accepted: 04/08/2017] [Indexed: 01/15/2023]
Abstract
Biosurfactant rhmnolipids have been applied in many fields, especially in environmental bioremediation. According to previous researches, many research groups have studied the influence of rhamnolipids on microorganism characteristics and/or its application in composting. In this review, the effects of rhamnolipids on the cell surface properties of microorganisms was discussed firstly, such as cell surface hydrophobicity (CSH), electrical, surface compounds, etc. Moreover, the deeper mechanisms were also discussed, such as the effects of rhamnolipids on the structural characteristics and functional characteristics of the cell membrane, and the effects of rhamnolipids on the related enzymes and genes. Additionally, the application of rhamnolipids in composting was discussed, which is an important way for pollutant biodegradation and resource reutilization. It is believed that rhamnolipids will play more and more important role in composting.
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Affiliation(s)
- Binbin Shao
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Zhifeng Liu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
| | - Hua Zhong
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China; State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, Hubei 430072, PR China.
| | - Guangming Zeng
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Guansheng Liu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Mingda Yu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Yang Liu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Xin Yang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Zhigang Li
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Zhendong Fang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Juntao Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Chenghao Zhao
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
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22
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Lima DF, Cohen RW, Rocha GA, Albano RM, Marques EA, Leão RS. Genomic information on multidrug-resistant livestock-associated methicillin-resistant Staphylococcus aureus ST398 isolated from a Brazilian patient with cystic fibrosis. Mem Inst Oswaldo Cruz 2017; 112:79-80. [PMID: 28076471 PMCID: PMC5225532 DOI: 10.1590/0074-02760160342] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/31/2016] [Indexed: 11/22/2022] Open
Abstract
Alarmingly, the isolation of methicillin-resistant Staphylococcus
aureus (MRSA) has been increasing among patients with cystic fibrosis
(CF). During a previous molecular characterisation of MRSA isolates obtained from
patients with CF from Rio de Janeiro, Brazil, one isolate was identified as the ST398
clone, a livestock-associated (LA) MRSA. In this study, we report the draft genome
sequence of an LA-MRSA ST398 clone isolated from a patient with CF.
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Affiliation(s)
- Danielle F Lima
- Universidade do Estado do Rio de Janeiro, Faculdade de Ciências Médicas, Departamento de Microbiologia, Imunologia e Parasitologia, Rio de Janeiro, RJ, Brasil
| | - Renata Wf Cohen
- Fundação Oswaldo Cruz-Fiocruz, Instituto Nacional de Saúde da Mulher, da Criança e do Adolescente Fernandes Figueira, Rio de Janeiro, RJ, Brasil
| | - Géssica A Rocha
- Universidade do Estado do Rio de Janeiro, Faculdade de Ciências Médicas, Departamento de Microbiologia, Imunologia e Parasitologia, Rio de Janeiro, RJ, Brasil
| | - Rodolpho M Albano
- Universidade do Estado do Rio de Janeiro, Departamento de Bioquímica, Instituto de Biologia Roberto Alcântara Gomes, Rio de Janeiro, RJ, Brasil
| | - Elizabeth A Marques
- Universidade do Estado do Rio de Janeiro, Faculdade de Ciências Médicas, Departamento de Microbiologia, Imunologia e Parasitologia, Rio de Janeiro, RJ, Brasil
| | - Robson S Leão
- Universidade do Estado do Rio de Janeiro, Faculdade de Ciências Médicas, Departamento de Microbiologia, Imunologia e Parasitologia, Rio de Janeiro, RJ, Brasil
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Quantitative Real-Time PCR (qPCR) Workflow for Analyzing Staphylococcus aureus Gene Expression. Methods Mol Biol 2016; 1373:143-54. [PMID: 25646613 DOI: 10.1007/7651_2014_193] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Quantitative real-time polymerase chain reaction (qPCR) is a sensitive tool that can be used to quantify and compare the amount of specific RNA transcripts between different biological samples. This chapter describes the use of a "two-step" qPCR method to calculate the relative fold change of expression of genes of interest in S. aureus. Using this work-flow, cDNA is synthesized from RNA templates (previously checked for the absence of significant genomic DNA contamination) using a cocktail of random primers and reverse-transcriptase enzyme. The cDNA pools generated can then be assessed for expression of specific genes of interest using SYBR Green-based qPCR and quantification of relative fold-change expression.
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Resilience in the Face of Uncertainty: Sigma Factor B Fine-Tunes Gene Expression To Support Homeostasis in Gram-Positive Bacteria. Appl Environ Microbiol 2016; 82:4456-4469. [PMID: 27208112 DOI: 10.1128/aem.00714-16] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Gram-positive bacteria are ubiquitous and diverse microorganisms that can survive and sometimes even thrive in continuously changing environments. The key to such resilience is the ability of members of a population to respond and adjust to dynamic conditions in the environment. In bacteria, such responses and adjustments are mediated, at least in part, through appropriate changes in the bacterial transcriptome in response to the conditions encountered. Resilience is important for bacterial survival in diverse, complex, and rapidly changing environments and requires coordinated networks that integrate individual, mechanistic responses to environmental cues to enable overall metabolic homeostasis. In many Gram-positive bacteria, a key transcriptional regulator of the response to changing environmental conditions is the alternative sigma factor σ(B) σ(B) has been characterized in a subset of Gram-positive bacteria, including the genera Bacillus, Listeria, and Staphylococcus Recent insight from next-generation-sequencing results indicates that σ(B)-dependent regulation of gene expression contributes to resilience, i.e., the coordination of complex networks responsive to environmental changes. This review explores contributions of σ(B) to resilience in Bacillus, Listeria, and Staphylococcus and illustrates recently described regulatory functions of σ(B).
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Omics Approaches for the Study of Adaptive Immunity to Staphylococcus aureus and the Selection of Vaccine Candidates. Proteomes 2016; 4:proteomes4010011. [PMID: 28248221 PMCID: PMC5217363 DOI: 10.3390/proteomes4010011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 02/05/2016] [Accepted: 03/01/2016] [Indexed: 01/20/2023] Open
Abstract
Staphylococcus aureus is a dangerous pathogen both in hospitals and in the community. Due to the crisis of antibiotic resistance, there is an urgent need for new strategies to combat S. aureus infections, such as vaccination. Increasing our knowledge about the mechanisms of protection will be key for the successful prevention or treatment of S. aureus invasion. Omics technologies generate a comprehensive picture of the physiological and pathophysiological processes within cells, tissues, organs, organisms and even populations. This review provides an overview of the contribution of genomics, transcriptomics, proteomics, metabolomics and immunoproteomics to the current understanding of S. aureus‑host interaction, with a focus on the adaptive immune response to the microorganism. While antibody responses during colonization and infection have been analyzed in detail using immunoproteomics, the full potential of omics technologies has not been tapped yet in terms of T-cells. Omics technologies promise to speed up vaccine development by enabling reverse vaccinology approaches. In consequence, omics technologies are powerful tools for deepening our understanding of the “superbug” S. aureus and for improving its control.
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Rouha H, Badarau A, Visram ZC, Battles MB, Prinz B, Magyarics Z, Nagy G, Mirkina I, Stulik L, Zerbs M, Jägerhofer M, Maierhofer B, Teubenbacher A, Dolezilkova I, Gross K, Banerjee S, Zauner G, Malafa S, Zmajkovic J, Maier S, Mabry R, Krauland E, Wittrup KD, Gerngross TU, Nagy E. Five birds, one stone: neutralization of α-hemolysin and 4 bi-component leukocidins of Staphylococcus aureus with a single human monoclonal antibody. MAbs 2015; 7:243-54. [PMID: 25523282 PMCID: PMC5045134 DOI: 10.4161/19420862.2014.985132] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen associated with high mortality. The emergence of antibiotic resistance and the inability of antibiotics to counteract bacterial cytotoxins involved in the pathogenesis of S. aureus call for novel therapeutic approaches, such as passive immunization with monoclonal antibodies (mAbs). The complexity of staphylococcal pathogenesis and past failures with single mAb products represent considerable barriers for antibody-based therapeutics. Over the past few years, efforts have focused on neutralizing α-hemolysin. Recent findings suggest that the concerted actions of several cytotoxins, including the bi-component leukocidins play important roles in staphylococcal pathogenesis. Therefore, we aimed to isolate mAbs that bind to multiple cytolysins by employing high diversity human IgG1 libraries presented on the surface of yeast cells. Here we describe cross-reactive antibodies with picomolar affinity for α-hemolysin and 4 different bi-component leukocidins that share only ∼26% overall amino acid sequence identity. The molecular basis of cross-reactivity is the recognition of a conformational epitope shared by α-hemolysin and F-components of gamma-hemolysin (HlgAB and HlgCB), LukED and LukSF (Panton-Valentine Leukocidin). The amino acids predicted to form the epitope are conserved and known to be important for cytotoxic activity. We found that a single cross-reactive antibody prevented lysis of human phagocytes, epithelial and red blood cells induced by α-hemolysin and leukocidins in vitro, and therefore had superior effectiveness compared to α-hemolysin specific antibodies to protect from the combined cytolytic effect of secreted S. aureus toxins. Such mAb afforded high levels of protection in murine models of pneumonia and sepsis.
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Key Words
- BLI, biolayer interferometry
- EC50, effective concentration
- Hla, α-hemolysin
- HlgAB and HlgCB, gamma-hemolysins
- IC50, inhibitory concentration
- LukED, leukocidin ED
- LukSF, leukocidin SF
- PMN, polymorphonuclear cells
- RBC, red blood cell
- Staphylococcus aureus
- engineered cross-reactivity
- exotoxins
- in vitro potency
- in vivo efficacy
- mAb, monoclonal antibody
- monoclonal antibody
- toxin neutralization
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Mutations upstream of fabI in triclosan resistant Staphylococcus aureus strains are associated with elevated fabI gene expression. BMC Genomics 2015; 16:345. [PMID: 25924916 PMCID: PMC4415318 DOI: 10.1186/s12864-015-1544-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 04/17/2015] [Indexed: 01/30/2023] Open
Abstract
Background The enoyl-acyl carrier protein (ACP) reductase enzyme (FabI) is the target for a series of antimicrobial agents including novel compounds in clinical trial and the biocide triclosan. Mutations in fabI and heterodiploidy for fabI have been shown to confer resistance in S. aureus strains in a previous study. Here we further determined the fabI upstream sequence of a selection of these strains and the gene expression levels in strains with promoter region mutations. Results Mutations in the fabI promoter were found in 18% of triclosan resistant clinical isolates, regardless the previously identified molecular mechanism conferring resistance. Although not significant, a higher rate of promoter mutations were found in strains without previously described mechanisms of resistance. Some of the mutations identified in the clinical isolates were also detected in a series of laboratory mutants. Microarray analysis of selected laboratory mutants with fabI promoter region mutations, grown in the absence of triclosan, revealed increased fabI expression in three out of four tested strains. In two of these strains, only few genes other than fabI were upregulated. Consistently with these data, whole genome sequencing of in vitro selected mutants identified only few mutations except the upstream and coding regions of fabI, with the promoter mutation as the most probable cause of fabI overexpression. Importantly the gene expression profiling of clinical isolates containing similar mutations in the fabI promoter also showed, when compared to unrelated non-mutated isolates, a significant up-regulation of fabI. Conclusions In conclusion, we have demonstrated the presence of C34T, T109G, and A101C mutations in the fabI promoter region of strains with fabI up-regulation, both in clinical isolates and/or laboratory mutants. These data provide further observations linking mutations upstream fabI with up-regulated expression of the fabI gene. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1544-y) contains supplementary material, which is available to authorized users.
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Kneuper H, Cao ZP, Twomey KB, Zoltner M, Jäger F, Cargill JS, Chalmers J, van der Kooi-Pol MM, van Dijl JM, Ryan RP, Hunter WN, Palmer T. Heterogeneity in ess transcriptional organization and variable contribution of the Ess/Type VII protein secretion system to virulence across closely related Staphylocccus aureus strains. Mol Microbiol 2014; 93:928-43. [PMID: 25040609 PMCID: PMC4285178 DOI: 10.1111/mmi.12707] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2014] [Indexed: 01/01/2023]
Abstract
The Type VII protein secretion system, found in Gram-positive bacteria, secretes small proteins, containing a conserved W-x-G amino acid sequence motif, to the growth medium. Staphylococcus aureus has a conserved Type VII secretion system, termed Ess, which is dispensable for laboratory growth but required for virulence. In this study we show that there are unexpected differences in the organization of the ess gene cluster between closely related strains of S. aureus. We further show that in laboratory growth medium different strains of S. aureus secrete the EsxA and EsxC substrate proteins at different growth points, and that the Ess system in strain Newman is inactive under these conditions. Systematic deletion analysis in S. aureus RN6390 is consistent with the EsaA, EsaB, EssA, EssB, EssC and EsxA proteins comprising core components of the secretion machinery in this strain. Finally we demonstrate that the Ess secretion machinery of two S. aureus strains, RN6390 and COL, is important for nasal colonization and virulence in the murine lung pneumonia model. Surprisingly, however, the secretion system plays no role in the virulence of strain SA113 under the same conditions.
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Affiliation(s)
- Holger Kneuper
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, UK
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