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Fang L, Cosgriff C, Alonzo F. Determinants of maturation of the Staphylococcus aureus autoinducing peptide. J Bacteriol 2024; 206:e0019524. [PMID: 39177535 PMCID: PMC11412329 DOI: 10.1128/jb.00195-24] [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: 05/03/2024] [Accepted: 07/23/2024] [Indexed: 08/24/2024] Open
Abstract
The accessory gene regulatory (Agr) system is required for virulence factor gene expression and pathogenesis of Staphylococcus aureus. The Agr system is activated in response to the accumulation of a cyclic autoinducing peptide (AIP), which is matured and secreted by the bacterium. The precursor of AIP, AgrD, consists of the AIP flanked by an N-terminal [Formula: see text]-helical Leader and a charged C-terminal tail. AgrD is matured to AIP by the action of two proteases, AgrB and MroQ. AgrB cleaves the C-terminal tail and promotes the formation of a thiolactone ring, whereas MroQ cleaves the N-terminal Leader in a manner that depends on the four-amino acid linker immediately following a conserved IG helix breaker motif. However, the attributes of AgrD that dictate the sequence of events in peptide maturation are not fully defined. Here, we used engineered AgrD peptide intermediates to ascertain the sufficiency of MroQ for N-terminal peptide cleavage, peptide export, and generation of mature AIP. We found that MroQ promotes the removal of the N-terminal Leader peptide from both linear and cyclic peptide intermediates, while peptide cyclization remained essential for signaling. The expression of the Leader peptide in isolation was sufficient for MroQ-dependent cleavage proximal to the four-amino-acid linker. In addition, active site mutations within AgrB destabilized full-length AgrD and thiolactone-containing intermediates and prevented the release of the Leader peptide. Altogether, our data support a tandem peptide maturation event involving both MroQ and AgrB that appears to couple protease activity and export of bioactive AIP.IMPORTANCEThe accessory gene regulatory (Agr) system is important for S. aureus pathogenesis. Activation of the Agr system requires recognition of a cyclic peptide pheromone, which must be fully matured to exert its biological activity. The complete events in cyclic peptide maturation and export from the bacterial cell remain to be fully defined. We and others recently discovered that the membrane peptidase MroQ is required for pheromone maturation. This study builds off the identification of MroQ and considers the attributes of the pheromone pro-peptide that are required for MroQ-mediated processing as well as uncovers features important for peptide stability and export. Overall, the findings in this study have implications for understanding bacterial pheromone maturation and virulence.
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Affiliation(s)
- Liwei Fang
- Department of Microbiology and Immunology, University of Illinois, Chicago, Illinois, USA
| | - Chance Cosgriff
- Department of Microbiology and Immunology, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois, USA
| | - Francis Alonzo
- Department of Microbiology and Immunology, University of Illinois, Chicago, Illinois, USA
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2
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Crepin DM, Chavignon M, Verhoeven PO, Laurent F, Josse J, Butin M. Staphylococcus capitis: insights into epidemiology, virulence, and antimicrobial resistance of a clinically relevant bacterial species. Clin Microbiol Rev 2024; 37:e0011823. [PMID: 38899876 PMCID: PMC11391707 DOI: 10.1128/cmr.00118-23] [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] [Indexed: 06/21/2024] Open
Abstract
SUMMARYStaphylococcus capitis is divided into two subspecies, S. capitis subsp. ureolyticus (renamed urealyticus in 1992; ATCC 49326) and S. capitis subsp. capitis (ATCC 27840), and fits with the archetype of clinically relevant coagulase-negative staphylococci (CoNS). S. capitis is a commensal bacterium of the skin in humans, which must be considered an opportunistic pathogen of interest particularly as soon as it is identified in a clinically relevant specimen from an immunocompromised patient. Several studies have highlighted the potential determinants underlying S. capitis pathogenicity, resistance profiles, and virulence factors. In addition, mobile genetic element acquisitions and mutations contribute to S. capitis genome adaptation to its environment. Over the past decades, antibiotic resistance has been identified for S. capitis in almost all the families of the currently available antibiotics and is related to the emergence of multidrug-resistant clones of high clinical significance. The present review summarizes the current knowledge concerning the taxonomic position of S. capitis among staphylococci, the involvement of this species in human colonization and diseases, the virulence factors supporting its pathogenicity, and the phenotypic and genomic antimicrobial resistance profiles of this species.
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Affiliation(s)
- Deborah M Crepin
- CIRI, Centre International de Recherche en Infectiologie, Staphylococcal pathogenesis team, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR 5308, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Marie Chavignon
- CIRI, Centre International de Recherche en Infectiologie, Staphylococcal pathogenesis team, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR 5308, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Paul O Verhoeven
- CIRI, Centre International de Recherche en Infectiologie, GIMAP Team, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR 5308, Ecole Normale Supérieure de Lyon, Lyon, France
- Faculté de Médecine, Université Jean Monnet, St-Etienne, France
- Service des agents infectieux et d'hygiène, Centre Hospitalier Universitaire de St-Etienne, St-Etienne, France
| | - Frédéric Laurent
- CIRI, Centre International de Recherche en Infectiologie, Staphylococcal pathogenesis team, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR 5308, Ecole Normale Supérieure de Lyon, Lyon, France
- Institut des Agents Infectieux, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
- Centre National de Référence des Staphylocoques, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
| | - Jérôme Josse
- CIRI, Centre International de Recherche en Infectiologie, Staphylococcal pathogenesis team, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR 5308, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Marine Butin
- CIRI, Centre International de Recherche en Infectiologie, Staphylococcal pathogenesis team, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR 5308, Ecole Normale Supérieure de Lyon, Lyon, France
- Service de Néonatologie et Réanimation Néonatale, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France
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3
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Benjamin KN, Goyal A, Nair RV, Endy D. Genome-wide transcription response of Staphylococcus epidermidis to heat shock and medically relevant glucose levels. Front Microbiol 2024; 15:1408796. [PMID: 39104585 PMCID: PMC11298487 DOI: 10.3389/fmicb.2024.1408796] [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: 03/28/2024] [Accepted: 06/24/2024] [Indexed: 08/07/2024] Open
Abstract
Skin serves as both barrier and interface between body and environment. Skin microbes are intermediaries evolved to respond, transduce, or act in response to changing environmental or physiological conditions. We quantified genome-wide changes in gene expression levels for one abundant skin commensal, Staphylococcus epidermidis, in response to an internal physiological signal, glucose levels, and an external environmental signal, temperature. We found 85 of 2,354 genes change up to ~34-fold in response to medically relevant changes in glucose concentration (0-17 mM; adj p ≤0.05). We observed carbon catabolite repression in response to a range of glucose spikes, as well as upregulation of genes involved in glucose utilization in response to persistent glucose. We observed 366 differentially expressed genes in response to a physiologically relevant change in temperature (37-45°C; adj p ≤ 0.05) and an S. epidermidis heat-shock response that mostly resembles the heat-shock response of related staphylococcal species. DNA motif analysis revealed CtsR and CIRCE operator sequences arranged in tandem upstream of dnaK and groESL operons. We identified and curated 38 glucose-responsive genes as candidate ON or OFF switches for use in controlling synthetic genetic systems. Such systems might be used to instrument the in-situ skin microbiome or help control microbes bioengineered to serve as embedded diagnostics, monitoring, or treatment platforms.
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Affiliation(s)
| | - Aditi Goyal
- Biomedical Data Science, Stanford University School of Medicine, Stanford, CA, United States
| | - Ramesh V. Nair
- Stanford Center for Genomics and Personalized Medicine, Stanford University School of Medicine, Stanford, CA, United States
| | - Drew Endy
- Bioengineering, Stanford University, Stanford, CA, United States
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4
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Volk CF, Proctor RA, Rose WE. The Complex Intracellular Lifecycle of Staphylococcus aureus Contributes to Reduced Antibiotic Efficacy and Persistent Bacteremia. Int J Mol Sci 2024; 25:6486. [PMID: 38928191 PMCID: PMC11203666 DOI: 10.3390/ijms25126486] [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: 05/20/2024] [Revised: 06/03/2024] [Accepted: 06/07/2024] [Indexed: 06/28/2024] Open
Abstract
Staphylococcus aureus bacteremia continues to be associated with significant morbidity and mortality, despite improvements in diagnostics and management. Persistent infections pose a major challenge to clinicians and have been consistently shown to increase the risk of mortality and other infectious complications. S. aureus, while typically not considered an intracellular pathogen, has been proven to utilize an intracellular niche, through several phenotypes including small colony variants, as a means for survival that has been linked to chronic, persistent, and recurrent infections. This intracellular persistence allows for protection from the host immune system and leads to reduced antibiotic efficacy through a variety of mechanisms. These include antimicrobial resistance, tolerance, and/or persistence in S. aureus that contribute to persistent bacteremia. This review will discuss the challenges associated with treating these complicated infections and the various methods that S. aureus uses to persist within the intracellular space.
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Affiliation(s)
- Cecilia F. Volk
- Pharmacy Practice and Translational Research Division, School of Pharmacy, Pharmacy University of Wisconsin-Madison, Madison, WI 53705, USA;
| | - Richard A. Proctor
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Warren E. Rose
- Pharmacy Practice and Translational Research Division, School of Pharmacy, Pharmacy University of Wisconsin-Madison, Madison, WI 53705, USA;
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
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5
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Mirza Agha M, Tavili E, Dabirmanesh B. Functional amyloids. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2024; 206:389-434. [PMID: 38811086 DOI: 10.1016/bs.pmbts.2024.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
While amyloid has traditionally been viewed as a harmful formation, emerging evidence suggests that amyloids may also play a functional role in cell biology, contributing to normal physiological processes that have been conserved throughout evolution. Functional amyloids have been discovered in several creatures, spanning from bacteria to mammals. These amyloids serve a multitude of purposes, including but not limited to, forming biofilms, melanin synthesis, storage, information transfer, and memory. The functional role of amyloids has been consistently validated by the discovery of more functional amyloids, indicating a conceptual convergence. The biology of amyloids is well-represented by non-pathogenic amyloids, given the numerous ones already identified and the ongoing rate of new discoveries. In this chapter, functional amyloids in microorganisms, animals, and plants are described.
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Affiliation(s)
- Mansoureh Mirza Agha
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Elaheh Tavili
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Bahareh Dabirmanesh
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
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Garrett SR, Palmer T. The role of proteinaceous toxins secreted by Staphylococcus aureus in interbacterial competition. FEMS MICROBES 2024; 5:xtae006. [PMID: 38495077 PMCID: PMC10941976 DOI: 10.1093/femsmc/xtae006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 02/17/2024] [Accepted: 02/27/2024] [Indexed: 03/19/2024] Open
Abstract
Staphylococcus aureus is highly adapted to colonization of the mammalian host. In humans the primary site of colonization is the epithelium of the nasal cavity. A major barrier to colonization is the resident microbiota, which have mechanisms to exclude S. aureus. As such, S. aureus has evolved mechanisms to compete with other bacteria, one of which is through secretion of proteinaceous toxins. S. aureus strains collectively produce a number of well-characterized Class I, II, and IV bacteriocins as well as several bacteriocin-like substances, about which less is known. These bacteriocins have potent antibacterial activity against several Gram-positive organisms, with some also active against Gram-negative species. S. aureus bacteriocins characterized to date are sporadically produced, and often encoded on plasmids. More recently the type VII secretion system (T7SS) of S. aureus has also been shown to play a role in interbacterial competition. The T7SS is encoded by all S. aureus isolates and so may represent a more widespread mechanism of competition used by this species. T7SS antagonism is mediated by the secretion of large protein toxins, three of which have been characterized to date: a nuclease toxin, EsaD; a membrane depolarizing toxin, TspA; and a phospholipase toxin, TslA. Further study is required to decipher the role that these different types of secreted toxins play in interbacterial competition and colonization of the host.
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Affiliation(s)
- Stephen R Garrett
- Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Tracy Palmer
- Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
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Yarrington KD, Shendruk TN, Limoli DH. The type IV pilus chemoreceptor PilJ controls chemotaxis of one bacterial species towards another. PLoS Biol 2024; 22:e3002488. [PMID: 38349934 PMCID: PMC10896506 DOI: 10.1371/journal.pbio.3002488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/26/2024] [Accepted: 01/05/2024] [Indexed: 02/15/2024] Open
Abstract
Bacteria live in social communities, where the ability to sense and respond to interspecies and environmental signals is critical for survival. We previously showed the pathogen Pseudomonas aeruginosa detects secreted peptides from bacterial competitors and navigates through interspecies signal gradients using pilus-based motility. Yet, it was unknown whether P. aeruginosa utilizes a designated chemosensory system for this behavior. Here, we performed a systematic genetic analysis of a putative pilus chemosensory system, followed by high-speed live-imaging and single-cell tracking, to reveal behaviors of mutants that retain motility but are blind to interspecies signals. The enzymes predicted to methylate (PilK) and demethylate (ChpB) the putative pilus chemoreceptor, PilJ, are necessary for cells to control the direction of migration. While these findings implicate PilJ as a bona fide chemoreceptor, such function had yet to be experimentally defined, as full-length PilJ is essential for motility. Thus, we constructed systematic genetic modifications of PilJ and found that without the predicted ligand binding domains or predicted methylation sites, cells lose the ability to detect competitor gradients, despite retaining pilus-mediated motility. Chemotaxis trajectory analysis revealed that increased probability and size of P. aeruginosa pilus-mediated steps towards S. aureus peptides, versus steps away, determines motility bias in wild type cells. However, PilJ mutants blind to interspecies signals take less frequent steps towards S. aureus or steps of equal size towards and away. Collectively, this work uncovers the chemosensory nature of PilJ, provides insight into how cell movements are biased during pilus-based chemotaxis, and identifies chemotactic interactions necessary for bacterial survival in polymicrobial communities, revealing putative pathways where therapeutic intervention might disrupt bacterial communication.
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Affiliation(s)
- Kaitlin D. Yarrington
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Tyler N. Shendruk
- School of Physics and Astronomy, The University of Edinburgh, Edinburgh, United Kingdom
| | - Dominique H. Limoli
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
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8
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Jiang JH, Cameron DR, Nethercott C, Aires-de-Sousa M, Peleg AY. Virulence attributes of successful methicillin-resistant Staphylococcus aureus lineages. Clin Microbiol Rev 2023; 36:e0014822. [PMID: 37982596 PMCID: PMC10732075 DOI: 10.1128/cmr.00148-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of severe and often fatal infections. MRSA epidemics have occurred in waves, whereby a previously successful lineage has been replaced by a more fit and better adapted lineage. Selection pressures in both hospital and community settings are not uniform across the globe, which has resulted in geographically distinct epidemiology. This review focuses on the mechanisms that trigger the establishment and maintenance of current, dominant MRSA lineages across the globe. While the important role of antibiotic resistance will be mentioned throughout, factors which influence the capacity of S. aureus to colonize and cause disease within a host will be the primary focus of this review. We show that while MRSA possesses a diverse arsenal of toxins including alpha-toxin, the success of a lineage involves more than just producing toxins that damage the host. Success is often attributed to the acquisition or loss of genetic elements involved in colonization and niche adaptation such as the arginine catabolic mobile element, as well as the activity of regulatory systems, and shift metabolism accordingly (e.g., the accessory genome regulator, agr). Understanding exactly how specific MRSA clones cause prolonged epidemics may reveal targets for therapies, whereby both core (e.g., the alpha toxin) and acquired virulence factors (e.g., the Panton-Valentine leukocidin) may be nullified using anti-virulence strategies.
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Affiliation(s)
- Jhih-Hang Jiang
- Department of Microbiology, Infection Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - David R. Cameron
- Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Cara Nethercott
- Department of Microbiology, Infection Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Marta Aires-de-Sousa
- Laboratory of Molecular Genetics, Institutode Tecnologia Químicae Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, Oeiras, Portugal
- Escola Superior de Saúde da Cruz Vermelha Portuguesa-Lisboa (ESSCVP-Lisboa), Lisbon, Portugal
| | - Anton Y. Peleg
- Department of Microbiology, Infection Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Centre to Impact Antimicrobial Resistance, Monash University, Clayton, Melbourne, Victoria, Australia
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9
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Marichal L, Bagnard L, Sire O, Vendrely C, Bruckert F, Weidenhaupt M. Phenol-soluble modulins form amyloids in contact with multiple surface chemistries. Biochim Biophys Acta Gen Subj 2023; 1867:130450. [PMID: 37640168 DOI: 10.1016/j.bbagen.2023.130450] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 08/24/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023]
Abstract
Functional amyloids are commonly produced by many microorganisms and their biological functions are numerous. Staphylococcus aureus can secrete a group of peptides named phenol-soluble modulins (PSMs) in their biofilm extracellular matrix. PSMs have been found inside biofilms both in their soluble form and assembled into amyloid structures. Yet, the actual biological function of these amyloids has been highly debated. Here, we assessed the ability of PSMs to form amyloids in contact with different abiotic surfaces to unravel a potential unknown bioadhesive and/or biofilm stabilization function. We combined surface plasmon resonance imaging, fluorescence aggregation kinetics, and FTIR spectroscopy in order to evaluate the PSM adsorption as well as amyloid formation properties in the presence of various surface chemistries. Overall, PSMs adsorb even on low-binding surfaces, making them highly adaptable adsorbants in the context of bioadhesion. Moreover, the PSM aggregation potential to form amyloid aggregates is not impacted by the presence of the surface chemistries tested. This versatility regarding adsorption and amyloid formation may imply a possible role of PSMs in biofilm adhesion and/or structure integrity.
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Affiliation(s)
- Laurent Marichal
- Université Grenoble Alpes, CNRS, Grenoble-INP LMGP, Grenoble F-38000, France
| | - Lucie Bagnard
- Université Grenoble Alpes, CNRS, Grenoble-INP LMGP, Grenoble F-38000, France
| | - Olivier Sire
- IRDL, UMR CNRS 6027, Université Bretagne Sud, Vannes, France
| | - Charlotte Vendrely
- Université Grenoble Alpes, CNRS, Grenoble-INP LMGP, Grenoble F-38000, France
| | - Franz Bruckert
- Université Grenoble Alpes, CNRS, Grenoble-INP LMGP, Grenoble F-38000, France
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10
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Wang X, Uppu DSSM, Dickey SW, Burgin DJ, Otto M, Lee JC. Staphylococcus aureus delta toxin modulates both extracellular membrane vesicle biogenesis and amyloid formation. mBio 2023; 14:e0174823. [PMID: 37795985 PMCID: PMC10653798 DOI: 10.1128/mbio.01748-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 08/15/2023] [Indexed: 10/06/2023] Open
Abstract
IMPORTANCE Extracellular membrane vesicles (MVs) produced by Staphylococcus aureus in planktonic cultures encapsulate a diverse cargo of bacterial proteins, nucleic acids, and glycopolymers that are protected from destruction by external factors. δ-toxin, a member of the phenol soluble modulin family, was shown to be critical for MV biogenesis. Amyloid fibrils co-purified with MVs generated by virulent, community-acquired S. aureus strains, and fibril formation was dependent on expression of the S. aureus δ-toxin gene (hld). Mass spectrometry data confirmed that the amyloid fibrils were comprised of δ-toxin. Although S. aureus MVs were produced in vivo in a localized murine infection model, amyloid fibrils were not observed in the in vivo setting. Our findings provide critical insights into staphylococcal factors involved in MV biogenesis and amyloid formation.
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Affiliation(s)
- Xiaogang Wang
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Divakara SSM Uppu
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Seth W. Dickey
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
- Department of Veterinary Medicine, Virginia-Maryland Regional College of Veterinary Medicine,University of Maryland, Bethesda, Maryland, USA
| | - Dylan J. Burgin
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Jean C. Lee
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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11
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Qi Y, Li Y, Li K, Xie T, Hua S, Guo Q, Zheng Y, Zhou M. Biocompatible Gallium Nanodots against Drug-Resistant Bacterial Pneumonia and Liver Abscess. ACS APPLIED MATERIALS & INTERFACES 2023; 15:39143-39156. [PMID: 37579188 DOI: 10.1021/acsami.3c07256] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
Resistant bacterial infection remains a severe public health threat, and conventional antibiotic drugs work poorly in effectively treating infectious diseases. Here, we developed gallium-based nanodots (Ga NDs), consisting of specific disruption of bacterial iron ability, to treat multidrug-resistant (MDR) Gram-negative bacteria-infected diseases. The Ga NDs significantly suppress the proliferation of two typical MDR bacteria strains (P. aeruginosa and ESBL E. coli) compared with clinically used antibacterial drugs, including penicillin and levofloxacin. Ga NDs could also disrupt the biofilms of these two bacterial strains. In P. aeruginosa infected pneumonia and ESBL E. coli infected acute liver abscess models, the Ga NDs enable substantial inhibition of bacterial growth and reduce the organs' inflammation that resulted in significant improvement of survival. Further, the Ga NDs demonstrated excellent biocompatibility and biosafety characteristics. Together, we believe that our gallium containing nanotherapeutics are expected to be developed into promising alternative therapies to combat drug-resistant bacterial infection.
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Affiliation(s)
- Yuchen Qi
- Eye Center, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 223300, P. R. China
- Zhejiang University-University of Edinburgh Institute (ZJU-UoE Institute), Zhejiang University School of Medicine, Zhejiang University, Haining 314400, P. R. China
| | - Yangyang Li
- Eye Center, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 223300, P. R. China
| | - Kun Li
- Department of Musculoskeletal Oncology, Fudan University Shanghai Cancer Center, Shanghai 210000, P. R. China
| | - Tingting Xie
- Zhejiang University-University of Edinburgh Institute (ZJU-UoE Institute), Zhejiang University School of Medicine, Zhejiang University, Haining 314400, P. R. China
| | - Shiyuan Hua
- Eye Center, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 223300, P. R. China
| | - Qunfeng Guo
- Department of Orthopedics, Shanghai Changzheng Hospital, Naval Medical University, Shanghai 200003, P. R. China
| | - Yichun Zheng
- Department of Urology, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 223300, P. R. China
| | - Min Zhou
- Eye Center, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 223300, P. R. China
- Zhejiang University-University of Edinburgh Institute (ZJU-UoE Institute), Zhejiang University School of Medicine, Zhejiang University, Haining 314400, P. R. China
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12
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Hsieh RC, Liu R, Burgin DJ, Otto M. Understanding mechanisms of virulence in MRSA: implications for antivirulence treatment strategies. Expert Rev Anti Infect Ther 2023; 21:911-928. [PMID: 37501364 DOI: 10.1080/14787210.2023.2242585] [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: 05/15/2023] [Accepted: 07/26/2023] [Indexed: 07/29/2023]
Abstract
INTRODUCTION Methicillin-resistant Staphylococcus aureus (MRSA) is a widespread pathogen, often causing recurrent and deadly infections in the hospital and community. Many S. aureus virulence factors have been suggested as potential targets for antivirulence therapy to decrease the threat of diminishing antibiotic availability. Antivirulence methods hold promise due to their adjunctive and prophylactic potential and decreased risk for selective pressure. AREAS COVERED This review describes the dominant virulence mechanisms exerted by MRSA and antivirulence therapeutics that are currently undergoing testing in clinical or preclinical stages. We also discuss the advantages and downsides of several investigational antivirulence approaches, including the targeting of bacterial transporters, host-directed therapy, and quorum-sensing inhibitors. For this review, a systematic search of literature on PubMed, Google Scholar, and Web of Science for relevant search terms was performed in April and May 2023. EXPERT OPINION Vaccine and antibody strategies have failed in clinical trials and could benefit from more basic science-informed approaches. Antivirulence-targeting approaches need to be set up better to meet the requirements of drug development, rather than only providing limited results to provide 'proof-of-principle' translational value of pathogenesis research. Nevertheless, there is great potential of such strategies and potential particular promise for novel probiotic approaches.
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Affiliation(s)
- Roger C Hsieh
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), U.S. National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Ryan Liu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), U.S. National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Dylan J Burgin
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), U.S. National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), U.S. National Institutes of Health (NIH), Bethesda, Maryland, USA
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Ganesan N, Mishra B, Felix L, Mylonakis E. Antimicrobial Peptides and Small Molecules Targeting the Cell Membrane of Staphylococcus aureus. Microbiol Mol Biol Rev 2023; 87:e0003722. [PMID: 37129495 PMCID: PMC10304793 DOI: 10.1128/mmbr.00037-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023] Open
Abstract
Clinical management of Staphylococcus aureus infections presents a challenge due to the high incidence, considerable virulence, and emergence of drug resistance mechanisms. The treatment of drug-resistant strains, such as methicillin-resistant S. aureus (MRSA), is further complicated by the development of tolerance and persistence to antimicrobial agents in clinical use. To address these challenges, membrane disruptors, that are not generally considered during drug discovery for agents against S. aureus, should be explored. The cell membrane protects S. aureus from external stresses and antimicrobial agents, but membrane-targeting antimicrobial agents are probably less likely to promote bacterial resistance. Nontypical linear cationic antimicrobial peptides (AMPs), highly modified AMPs such as daptomycin (lipopeptide), bacitracin (cyclic peptide), and gramicidin S (cyclic peptide), are currently in clinical use. Recent studies have demonstrated that AMPs and small molecules can penetrate the cell membrane of S. aureus, inhibit phospholipid biosynthesis, or block the passage of solutes between the periplasm and the exterior of the cell. In addition to their primary mechanism of action (MOA) that targets the bacterial membrane, AMPs and small molecules may also impact bacteria through secondary mechanisms such as targeting the biofilm, and downregulating virulence genes of S. aureus. In this review, we discuss the current state of research into cell membrane-targeting AMPs and small molecules and their potential mechanisms of action against drug-resistant physiological forms of S. aureus, including persister cells and biofilms.
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Affiliation(s)
- Narchonai Ganesan
- Infectious Diseases Division, Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Biswajit Mishra
- Infectious Diseases Division, Alpert Medical School, Brown University, Providence, Rhode Island, USA
- Department of Medicine, The Miriam Hospital, Providence, Rhode Island, USA
| | - LewisOscar Felix
- Infectious Diseases Division, Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Eleftherios Mylonakis
- Infectious Diseases Division, Alpert Medical School, Brown University, Providence, Rhode Island, USA
- Department of Medicine, Houston Methodist Hospital, Houston, Texas, USA
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Polaske TJ, West KHJ, Zhao K, Widner DL, York JT, Blackwell HE. Chemical and biomolecular insights into the Staphylococcus aureus agr quorum sensing system: Current progress and ongoing challenges. Isr J Chem 2023; 63:e202200096. [PMID: 38765792 PMCID: PMC11101167 DOI: 10.1002/ijch.202200096] [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: 10/31/2022] [Indexed: 03/19/2023]
Abstract
Staphylococcus aureus is a ubiquitous bacterium that has become a major threat to human health due to its extensive toxin production and tremendous capacity for antibiotic resistance (e.g., MRSA "superbug" infections). Amid a worsening antibiotic resistance crisis, new strategies to combat this deadly microbe that remove the selective pressure of traditional approaches are in high demand. S. aureus utilizes an accessory gene regulator (agr) quorum sensing network to monitor its local cellular population and trigger a devastating communal attack, like an invading horde, once a threshold cell density has been reached. The role of the agr system in a range of disease types is still being unraveled. Herein, we discuss the present-day biochemical understanding of agr along with unresolved details, describe its connection to the progression of infection, and review how chemical strategies have been implemented to study and intercept this signaling pathway. This research is illuminating the potential of agr as an anti-virulence target in S. aureus and should inform the study of similar, yet less studied, agr systems in related bacterial pathogens.
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Affiliation(s)
- Thomas J. Polaske
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706 USA
| | - Korbin H. J. West
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706 USA
| | - Ke Zhao
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706 USA
| | - Danielle L. Widner
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706 USA
| | - Jordan T. York
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706 USA
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706 USA
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15
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Wang X, Uppu DS, Dickey SW, Burgin DJ, Otto M, Lee JC. Staphylococcus aureus Delta Toxin Modulates both Extracellular Membrane Vesicle Biogenesis and Amyloid Formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.23.533957. [PMID: 36993475 PMCID: PMC10055364 DOI: 10.1101/2023.03.23.533957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Staphylococcus aureus secretes phenol-soluble modulins (PSMs), a family of small, amphipathic, secreted peptides with multiple biologic activities. Community-acquired S. aureus strains produce high levels of PSMs in planktonic cultures, and PSM alpha peptides have been shown to augment the release of extracellular membrane vesicles (MVs). We observed that amyloids, aggregates of proteins characterized by a fibrillar morphology and stained with specific dyes, co-purified with MVs harvested from cell-free culture supernatants of community-acquired S. aureus strains. δ-toxin was a major component of amyloid fibrils that co-purified with strain LAC MVs, and δ-toxin promoted the production of MVs and amyloid fibrils in a dose-dependent manner. To determine whether MVs and amyloid fibrils were generated under in vivo conditions, we inoculated mice with S. aureus harvested from planktonic cultures. Bacterial MVs could be isolated and purified from lavage fluids recovered from infected animals. Although δ-toxin was the most abundant PSM in lavage fluids, amyloid fibrils could not be detected in these samples. Our findings expand our understanding of amyloid fibril formation in S. aureus cultures, reveal important roles of δ-toxin in amyloid fibril formation and MV biogenesis, and demonstrate that MVs are generated in vivo in a staphylococcal infection model. Importance Extracellular membrane vesicles (MVs) produced by Staphylococcus aureus in planktonic cultures encapsulate a diverse cargo of bacterial proteins, nucleic acids, and glycopolymers that are protected from destruction by external factors. δ-toxin, a member of the phenol soluble modulin family, was shown to be critical for MV biogenesis. Amyloid fibrils co-purified with MVs generated by virulent, community-acquired S. aureus strains, and fibril formation was dependent on expression of the S. aureus δ-toxin gene ( hld ). Mass spectrometry data confirmed that the amyloid fibrils were comprised of δ-toxin. Although S. aureus MVs were produced in vivo in a localized murine infection model, amyloid fibrils were not observed in the in vivo setting. Our findings provide critical insights into staphylococcal factors involved in MV biogenesis and amyloid formation.
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Dickey SW, Burgin DJ, Huang S, Maguire D, Otto M. Two transporters cooperate to secrete amphipathic peptides from the cytoplasmic and membranous milieus. Proc Natl Acad Sci U S A 2023; 120:e2211689120. [PMID: 36787359 PMCID: PMC9974410 DOI: 10.1073/pnas.2211689120] [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: 07/07/2022] [Accepted: 01/18/2023] [Indexed: 02/15/2023] Open
Abstract
Diverse organisms secrete amphipathic biomolecules for competitive gains. However, how cells cope with producing these membrane-permeabilizing molecules is unclear. We focused on the PSM family of secreted amphipathic peptides in the pathogen Staphylococcus aureus that uses two ABC transporters, PmtCD and AbcA, to export peptides across the bacterial cell membrane. We found that increased peptide hydrophobicity favors PSM secretion through PmtCD over AbcA and that only PmtCD protected cells against amphipathic peptides. We propose a two-system model in which PmtCD and AbcA independently export PSMs from either membrane or cytosolic environments, respectively. Our model provides a rationale for the encoding of multiple transport systems on diverse biosynthetic gene clusters used to produce distinct amphipathic molecules. In addition, our data serve as a guide for selectively blocking PSM secretion to achieve antimicrobial or antivirulence approaches and to disrupt established roles of PSM-mediated virulence.
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Affiliation(s)
- Seth W. Dickey
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
- National Institute of General Medical Sciences, NIH, Bethesda, MD20892
- Department of Veterinary Medicine, University of Maryland, College Park, MD20740
- Virginia-Maryland College of Veterinary Medicine, College Park, MD20740
| | - Dylan J. Burgin
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
| | - Steven Huang
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
| | - David Maguire
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
| | - Michael Otto
- National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD20892
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Satishkumar N, Lai LY, Mukkayyan N, Vogel BE, Chatterjee SS. A Nonclassical Mechanism of β-Lactam Resistance in Methicillin-Resistant Staphylococcus aureus and Its Effect on Virulence. Microbiol Spectr 2022; 10:e0228422. [PMID: 36314912 PMCID: PMC9769611 DOI: 10.1128/spectrum.02284-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 10/07/2022] [Indexed: 11/07/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a group of pathogenic bacteria that are infamously resistant to β-lactam antibiotics, a property attributed to the mecA gene. Recent studies have reported that mutations associated with the promoter region of pbp4 demonstrated high levels of β-lactam resistance, suggesting the role of PBP4 as an important non-mecA mediator of β-lactam resistance. The pbp4-promoter-associated mutations have been detected in strains with or without mecA. Our previous studies that were carried out in strains devoid of mecA described that pbp4-promoter-associated mutations lead to PBP4 overexpression and β-lactam resistance. In this study, by introducing various pbp4-promoter-associated mutations in the genome of a MRSA strain, we demonstrate that PBP4 overexpression can supplement mecA-associated resistance in S. aureus and can lead to increased β-lactam resistance. The promoter and regulatory region of pbp4 is shared with a divergently transcribed gene, abcA, which encodes a multidrug exporter. We demonstrate that the promoter mutations caused an upregulation of pbp4 and downregulation of abcA, confirming that the resistant phenotype is associated with PBP4 overexpression. PBP4 has also been associated with staphylococcal pathogenesis, however, its exact role remains unclear. Using a Caenorhabditis elegans model, we demonstrate that strains having increased PBP4 expression are less virulent than wild-type strains, suggesting that β-lactam resistance mediated via PBP4 likely comes at the cost of virulence. IMPORTANCE Our study demonstrates the ability of PBP4 to be an important mediator of β-lactam resistance in not only methicillin-susceptible Staphylococcus aureus (MSSA) background strains as previously demonstrated but also in MRSA strains. When present together, PBP2a and PBP4 overexpression can produce increased levels of β-lactam resistance, causing complications in treatment. Thus, this study suggests the importance of monitoring PBP4-associated resistance in clinical settings, as well as understanding the mechanistic basis of associated resistance, so that treatments targeting PBP4 may be developed. This study also demonstrates that S. aureus strains with increased PBP4 expression are less pathogenic, providing important hints about the role of PBP4 in S. aureus resistance and pathogenesis.
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Affiliation(s)
- Nidhi Satishkumar
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Li-Yin Lai
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Nagaraja Mukkayyan
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
| | - Bruce E. Vogel
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Som S. Chatterjee
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, USA
- Institute of Marine and Environmental Technology (IMET), Baltimore, Maryland, USA
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18
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Reshamwala K, Cheung GYC, Hsieh RC, Liu R, Joo HS, Zheng Y, Bae JS, Nguyen TH, Villaruz AE, Gozalo AS, Elkins WR, Otto M. Identification and characterization of the pathogenic potential of phenol-soluble modulin toxins in the mouse commensal Staphylococcus xylosus. Front Immunol 2022; 13:999201. [PMID: 36189200 PMCID: PMC9520458 DOI: 10.3389/fimmu.2022.999201] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 08/25/2022] [Indexed: 11/16/2022] Open
Abstract
In contrast to the virulent human skin commensal Staphylococcus aureus, which secretes a plethora of toxins, other staphylococci have much reduced virulence. In these species, commonly the only toxins are those of the phenol-soluble modulin (PSM) family. PSMs are species-specific and have only been characterized in a limited number of species. S. xylosus is a usually innocuous commensal on the skin of mice and other mammals. Prompted by reports on the involvement of PSMs in atopic dermatitis (AD) and the isolation of S. xylosus from mice with AD-like symptoms, we here identified and characterized PSMs of S. xylosus with a focus on a potential involvement in AD phenotypes. We found that most clinical S. xylosus strains produce two PSMs, one of the shorter α- and one of the longer β-type, which were responsible for almost the entire lytic and pro-inflammatory capacities of S. xylosus. Importantly, PSMα of S. xylosus caused lysis and degranulation of mast cells at degrees higher than that of S. aureus δ-toxin, the main PSM previously associated with AD. However, S. xylosus did not produce significant AD symptoms in wild-type mice as opposed to S. aureus, indicating that promotion of AD by S. xylosus likely requires a predisposed host. Our study indicates that non-specific cytolytic potency rather than specific interaction underlies PSM-mediated mast cell degranulation and suggest that the previously reported exceptional potency of δ-toxin of S. aureus is due to its high-level production. Furthermore, they suggest that species that produce cytolytic PSMs, such as S. xylosus, all have the capacity to promote AD, but a high combined level of PSM cytolytic potency is required to cause AD in a non-predisposed host.
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Affiliation(s)
- Kunal Reshamwala
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Gordon Y. C. Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
- *Correspondence: Michael Otto, ; Gordon Y. C. Cheung,
| | - Roger C. Hsieh
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Ryan Liu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Yue Zheng
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Justin S. Bae
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Thuan H. Nguyen
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Amer E. Villaruz
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
| | - Alfonso S. Gozalo
- Comparative Medicine Branch (CMB), NIAID, NIH, Bethesda, MD, United States
| | - William R. Elkins
- Comparative Medicine Branch (CMB), NIAID, NIH, Bethesda, MD, United States
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), United States (US) National Institutes of Health (NIH), Bethesda, MD, United States
- *Correspondence: Michael Otto, ; Gordon Y. C. Cheung,
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Ribeiro M, Sousa M, Borges V, Gomes JP, Duarte S, Isidro J, Vieira L, Torres C, Santos H, Capelo JL, Poeta P, Igrejas G. Bioinformatics study of expression from genomes of epidemiologically related MRSA CC398 isolates from human and wild animal samples. J Proteomics 2022; 268:104714. [PMID: 36058542 DOI: 10.1016/j.jprot.2022.104714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 08/28/2022] [Indexed: 10/14/2022]
Abstract
One of the most important livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) genetic lineages is the clonal complex (CC) 398, which can cause typical S. aureus-associated infections in people. In this work, whole-genome sequencing, RNA-sequencing, and gel-based comparative proteomics were applied to study the genetic characteristics of three MRSA CC398 isolates recovered from humans (strains C5621 and C9017), and from an animal (strain OR418). Of the three strains, C9017 presented the broadest resistance genotype, including resistance to fluroquinolone, clindamycin, tiamulin, macrolide and aminoglycoside antimicrobial classes. The scn, sak, and chp genes of the immune evasion cluster system were solely detected in OR418. Pangenome analysis showed a total of 288 strain-specific genes, most of which are hypothetical or phage-related proteins. OR418 had the most pronounced genetic differences. RNAIII (δ-hemolysin) gene was clearly the most expressed gene in OR418 and C5621, but it was not detected in C9017. Significant differences in the proteome profiles were found between strains. For example, the immunoglobulin-binding protein Sbi was more abundant in OR418. Considering that Sbi is a multifunctional immune evasion factor in S. aureus, the results point to OR418 strain having high zoonotic potential. Overall, multiomics biomarker signatures can assume an important role to advance precision medicine in the years to come. SIGNIFICANCE: MRSA is one of the most representative drug-resistant pathogens and its dissemination is increasing due to MRSA capability of establishing new reservoirs. LA-MRSA is considered an emerging problem worldwide and CC398 is one of the most important genetic lineages. In this study, three MRSA CC398 isolates recovered from humans and from a wild animal were analyzed through whole-genome sequencing, RNA-sequencing, and gel-based comparative proteomics in order to gather systems-wide omics data and better understand the genetic characteristics of this lineage to identify distinctive markers and genomic features of relevance to public health. The scn, sak, and chp genes of the immune evasion cluster system were solely detected in OR418. Pangenome analysis showed a total of 288 strain-specific genes, most of which are hypothetical or phage-related proteins. OR418 had the most pronounced genetic differences. RNAIII (δ-hemolysin) gene was clearly the most expressed gene in OR418 and C5621, but it was not detected in C9017. Significant differences in the proteome profiles were found between strains.
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Affiliation(s)
- Miguel Ribeiro
- Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal; Functional Genomics and Proteomics Unity, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal; Associated Laboratory for Green Chemistry (LAQV-REQUIMTE), Faculty of Science and Technology, University Nova of Lisbon, 2829-546 Caparica, Portugal
| | - Margarida Sousa
- Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal; Functional Genomics and Proteomics Unity, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal; Associated Laboratory for Green Chemistry (LAQV-REQUIMTE), Faculty of Science and Technology, University Nova of Lisbon, 2829-546 Caparica, Portugal
| | - Vítor Borges
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, 1600-609 Lisbon, Portugal
| | - João Paulo Gomes
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, 1600-609 Lisbon, Portugal
| | - Sílvia Duarte
- Technology and Innovation Unit, Department of Human Genetics, National Institute of Health, Lisbon, Portugal
| | - Joana Isidro
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, 1600-609 Lisbon, Portugal; Technology and Innovation Unit, Department of Human Genetics, National Institute of Health, Lisbon, Portugal
| | - Luís Vieira
- Technology and Innovation Unit, Department of Human Genetics, National Institute of Health, Lisbon, Portugal
| | - Carmen Torres
- Biochemistry and Molecular Biology Unit, Faculty of Science and Technology, University of La Rioja, 26006 Logroño, Spain
| | - Hugo Santos
- BIOSCOPE Research Group, LAQV-REQUIMTE, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal; PROTEOMASS Scientific Society, Madan Parque, Rua dos Inventores, 2825-182 Caparica, Portugal; Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - José Luís Capelo
- BIOSCOPE Research Group, LAQV-REQUIMTE, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal; PROTEOMASS Scientific Society, Madan Parque, Rua dos Inventores, 2825-182 Caparica, Portugal
| | - Patrícia Poeta
- Associated Laboratory for Green Chemistry (LAQV-REQUIMTE), Faculty of Science and Technology, University Nova of Lisbon, 2829-546 Caparica, Portugal; Microbiology and Antibiotic Resistance Team (MicroART), Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro (UTAD), Vila Real 5000-801, Portugal; CECAV-Veterinary and Animal Research Centre, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal; Associate Laboratory for Animal and Veterinary Science (AL4AnimalS), University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
| | - Gilberto Igrejas
- Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal; Functional Genomics and Proteomics Unity, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal; Associated Laboratory for Green Chemistry (LAQV-REQUIMTE), Faculty of Science and Technology, University Nova of Lisbon, 2829-546 Caparica, Portugal.
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Wall Teichoic Acids Facilitate the Release of Toxins from the Surface of Staphylococcus aureus. Microbiol Spectr 2022; 10:e0101122. [PMID: 35863033 PMCID: PMC9430763 DOI: 10.1128/spectrum.01011-22] [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] [Indexed: 11/20/2022] Open
Abstract
A major feature of the pathogenicity of Staphylococcus aureus is its ability to secrete cytolytic toxins. This process involves the translocation of the toxins from the cytoplasm through the bacterial membrane and the cell wall to the external environment. The process of their movement through the membrane is relatively well defined, involving both general and toxin-specific secretory systems. Movement of the toxins through the cell wall was considered to involve the passive diffusion of the proteins through the porous cell wall structures; however, recent work suggests that this is more complex, and here we demonstrate a role for the wall teichoic acids (WTA) in this process. Utilizing a genome-wide association approach, we identified a polymorphism in the locus encoding the WTA biosynthetic machinery as associated with the cytolytic activity of the bacteria. We verified this association using an isogenic mutant set and found that WTA are required for the release of several cytolytic toxins from the bacterial cells. We show that this effect is mediated by a change in the electrostatic charge across the cell envelope that results from the loss of WTA. As a major target for the development of novel therapeutics, it is important that we fully understand the entire process of cytolytic toxin production and release. These findings open up a new aspect to the process of toxin release by a major human pathogen while also demonstrating that clinical isolates can utilize WTA production to vary their cytotoxicity, thereby altering their pathogenic capabilities. IMPORTANCE The production and release of cytolytic toxins is a critical aspect for the pathogenicity of many bacterial pathogens. In this study, we demonstrate a role for wall teichoic acids, molecules that are anchored to the peptidoglycan of the bacterial cell wall, in the release of toxins from S. aureus cells into the extracellular environment. Our findings suggest that this effect is mediated by a gradient of electrostatic charge which the presence of the negatively charged WTA molecules create across the cell envelope. This work brings an entirely new aspect to our understanding of the cytotoxicity of S. aureus and demonstrates a further means by which this major human pathogen can adapt its pathogenic capabilities.
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21
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Genotypes of Staphylococcus aureus Clinical Isolates Are Associated with Phenol-Soluble Modulin (PSM) Production. Toxins (Basel) 2022; 14:toxins14080556. [PMID: 36006218 PMCID: PMC9412541 DOI: 10.3390/toxins14080556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/06/2022] [Accepted: 08/12/2022] [Indexed: 12/01/2022] Open
Abstract
Phenol-soluble modulins (PSMs) are important S. aureus virulence factors that cause cytolysis, mast cell degranulation, and stimulate inflammatory responses. In this study, PSM production by S. aureus clinical isolates was measured by liquid chromatography/mass spectrometry (LC-MS) and correlated with staphylococcal protein A (spa) type and staphylococcal cassette chromosome mec (SCCmec) type. Of 106 S. aureus clinical isolates, 50 (47.2%) corresponded to methicillin-susceptible S. aureus (MSSA) and 56 (52.8%) to methicillin-resistant S. aureus (MRSA). LC-MS analysis revealed no significant difference in average PSMα3, PSMα4, PSMβ2, and δ-toxin production between MSSA and MRSA isolates, but PSMα1, PSMα2, and PSMβ1 production were higher in MSSA than MRSA. This study demonstrated that average PSMα1–α4, PSMβ1–β2, and δ-toxin production by SCCmec type II strains was significantly lower than the IV, IVA, and V strains. Most of the SCCmec type II strains (n = 17/25; 68.0%) did not produce δ-toxin, suggesting a dysfunctional Agr system. The spa type t111 (except one strain) and t2460 (except one strain producing PSM α1–α4) did not produce PSMα1–α4 and δ-toxin, while average PSM production was higher among the t126 and t1784 strains. This study showed that the genotype of S. aureus, specifically the spa and SCCmec types, is important in characterizing the production of PSMs.
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22
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Blair JMA, Zeth K, Bavro VN, Sancho-Vaello E. The role of bacterial transport systems in the removal of host antimicrobial peptides in Gram-negative bacteria. FEMS Microbiol Rev 2022; 46:6617596. [PMID: 35749576 PMCID: PMC9629497 DOI: 10.1093/femsre/fuac032] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 05/23/2022] [Accepted: 06/22/2022] [Indexed: 01/09/2023] Open
Abstract
Antibiotic resistance is a global issue that threatens our progress in healthcare and life expectancy. In recent years, antimicrobial peptides (AMPs) have been considered as promising alternatives to the classic antibiotics. AMPs are potentially superior due to their lower rate of resistance development, since they primarily target the bacterial membrane ('Achilles' heel' of the bacteria). However, bacteria have developed mechanisms of AMP resistance, including the removal of AMPs to the extracellular space by efflux pumps such as the MtrCDE or AcrAB-TolC systems, and the internalization of AMPs to the cytoplasm by the Sap transporter, followed by proteolytic digestion. In this review, we focus on AMP transport as a resistance mechanism compiling all the experimental evidence for the involvement of efflux in AMP resistance in Gram-negative bacteria and combine this information with the analysis of the structures of the efflux systems involved. Finally, we expose some open questions with the aim of arousing the interest of the scientific community towards the AMPs-efflux pumps interactions. All the collected information broadens our understanding of AMP removal by efflux pumps and gives some clues to assist the rational design of AMP-derivatives as inhibitors of the efflux pumps.
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Affiliation(s)
- Jessica M A Blair
- College of Medical and Dental Sciences, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Kornelius Zeth
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000 Roskilde, Denmark
| | - Vassiliy N Bavro
- School of Life Sciences, University of Essex, Colchester, CO4 3SQ, United Kingdom
| | - Enea Sancho-Vaello
- Corresponding author. College of Medical and Dental Sciences, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom. E-mail:
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Sionov RV, Steinberg D. Targeting the Holy Triangle of Quorum Sensing, Biofilm Formation, and Antibiotic Resistance in Pathogenic Bacteria. Microorganisms 2022; 10:1239. [PMID: 35744757 PMCID: PMC9228545 DOI: 10.3390/microorganisms10061239] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 12/12/2022] Open
Abstract
Chronic and recurrent bacterial infections are frequently associated with the formation of biofilms on biotic or abiotic materials that are composed of mono- or multi-species cultures of bacteria/fungi embedded in an extracellular matrix produced by the microorganisms. Biofilm formation is, among others, regulated by quorum sensing (QS) which is an interbacterial communication system usually composed of two-component systems (TCSs) of secreted autoinducer compounds that activate signal transduction pathways through interaction with their respective receptors. Embedded in the biofilms, the bacteria are protected from environmental stress stimuli, and they often show reduced responses to antibiotics, making it difficult to eradicate the bacterial infection. Besides reduced penetration of antibiotics through the intricate structure of the biofilms, the sessile biofilm-embedded bacteria show reduced metabolic activity making them intrinsically less sensitive to antibiotics. Moreover, they frequently express elevated levels of efflux pumps that extrude antibiotics, thereby reducing their intracellular levels. Some efflux pumps are involved in the secretion of QS compounds and biofilm-related materials, besides being important for removing toxic substances from the bacteria. Some efflux pump inhibitors (EPIs) have been shown to both prevent biofilm formation and sensitize the bacteria to antibiotics, suggesting a relationship between these processes. Additionally, QS inhibitors or quenchers may affect antibiotic susceptibility. Thus, targeting elements that regulate QS and biofilm formation might be a promising approach to combat antibiotic-resistant biofilm-related bacterial infections.
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Affiliation(s)
- Ronit Vogt Sionov
- The Biofilm Research Laboratory, The Institute of Biomedical and Oral Research, The Faculty of Dental Medicine, Hadassah Medical School, The Hebrew University, Jerusalem 9112102, Israel;
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Thymol Reduces agr-Mediated Virulence Factor Phenol-Soluble Modulin Production in Staphylococcus aureus. BIOMED RESEARCH INTERNATIONAL 2022; 2022:8221622. [PMID: 35586806 PMCID: PMC9110180 DOI: 10.1155/2022/8221622] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 04/08/2022] [Accepted: 04/23/2022] [Indexed: 12/12/2022]
Abstract
Staphylococcus aureus is a major human bacterial pathogen that carries a large number of virulence factors. Many virulence factors of S. aureus are regulated by the accessory gene regulator (agr) quorum-sensing system. Phenol-soluble modulins (PSMs) are one of the agr-mediated virulence determinants known to play a significant role in S. aureus pathogenesis. In the present study, the efficacy of thymol to inhibit PSM production including δ-toxin in S. aureus was explored. We employed liquid chromatography-mass spectrometry (LC-MS) to quantify the PSMsα1-PSMα4, PSMβ1 and PSMβ2, and δ-toxin production from culture supernatants. We found that thymol at 0.5 MIC (128 μg/mL) significantly reduced the PSMα and δ-toxin production in S. aureus WKZ-1, WKZ-2, LAC USA300, and ATCC29213. Downregulation in transcription by quantitative real-time (qRT) PCR analysis of response regulator agrA and receptor histidine kinase agrC upon 0.5 MIC thymol treatment affirmed the results of LC-MS quantification of PSMs. In silico molecular docking analysis demonstrated the binding affinity of thymol with receptors AgrA and AgrC. Transmission electron microscopy images revealed no ultrastructural alterations (cell wall and membrane) in thymol-treated WKZ-1 and WKZ-2 S. aureus strains. Here, we demonstrated that thymol reduces various PSM production in S. aureus clinical isolates and reference strains with mass spectrometry.
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Effects of Growth Stage on the Characterization of Enterotoxin A-Producing Staphylococcus aureus‐Derived Membrane vesicles. Microorganisms 2022; 10:microorganisms10030574. [PMID: 35336149 PMCID: PMC8948643 DOI: 10.3390/microorganisms10030574] [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: 01/20/2022] [Revised: 03/02/2022] [Accepted: 03/04/2022] [Indexed: 11/17/2022] Open
Abstract
Virulence factors, such as staphylococcal enterotoxin A (SEA), are contained within membrane vesicles (MVs) in the cell membrane of Staphylococcus aureus. In this study, the effects of the growth stage on quantitative and qualitative changes in the components contained in the MVs of S. aureus SEA-producing strains were examined. Changes in the expression levels of S. aureus genes were examined at each growth stage; phenol-soluble modulin (PSM) gene reached a maximum after 8 h, and the expression of cell membrane-related genes was decreased after 6 h. Based on these gene expression patterns, MVs were prepared at 6, 17, and 24 h. The particle size of MVs did not change depending on the growth stage. MVs prepared after culture for 17 h maintained their particle size when stored at 23 °C. The amount of SEA in the culture supernatant and MVs were not correlated. Bifunctional autolysin, a protein involved in cell wall biosynthesis/degradation, was increased in MVs at 17 h. The expression pattern of inflammation-related genes in human adult low calcium high temperature (HaCaT) cells induced by MVs was different for each growth stage. The inclusion components of S. aureus-derived MVs are selective, depend on the stage of growth, and may play an important role in toxicity.
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Kember M, Grandy S, Raudonis R, Cheng Z. Non-Canonical Host Intracellular Niche Links to New Antimicrobial Resistance Mechanism. Pathogens 2022; 11:pathogens11020220. [PMID: 35215166 PMCID: PMC8876822 DOI: 10.3390/pathogens11020220] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 02/03/2022] [Accepted: 02/05/2022] [Indexed: 12/04/2022] Open
Abstract
Globally, infectious diseases are one of the leading causes of death among people of all ages. The development of antimicrobials to treat infectious diseases has been one of the most significant advances in medical history. Alarmingly, antimicrobial resistance is a widespread phenomenon that will, without intervention, make currently treatable infections once again deadly. In an era of widespread antimicrobial resistance, there is a constant and pressing need to develop new antibacterial drugs. Unraveling the underlying resistance mechanisms is critical to fight this crisis. In this review, we summarize some emerging evidence of the non-canonical intracellular life cycle of two priority antimicrobial-resistant bacterial pathogens: Pseudomonas aeruginosa and Staphylococcus aureus. The bacterial factors that modulate this unique intracellular niche and its implications in contributing to resistance are discussed. We then briefly discuss some recent research that focused on the promises of boosting host immunity as a combination therapy with antimicrobials to eradicate these two particular pathogens. Finally, we summarize the importance of various strategies, including surveillance and vaccines, in mitigating the impacts of antimicrobial resistance in general.
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Sub-Inhibitory Concentrations of Oxacillin, but Not Clindamycin, Linezolid, or Tigecycline, Decrease Staphylococcal Phenol-Soluble Modulin Expression in Community-Acquired Methicillin-Resistant Staphylococcus aureus. Microbiol Spectr 2022; 10:e0080821. [PMID: 35044221 PMCID: PMC8768629 DOI: 10.1128/spectrum.00808-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Staphylococcus aureus (SA) is a major human pathogen producing virulence factors, such as Panton-Valentine-leucocidin (PVL), alpha-hemolysin (Hla), and phenol-soluble-modulins alpha (PSMα), including delta-hemolysin (Hld). Unlike oxacillin, clindamycin and linezolid subinhibitory concentrations (sub-MIC) display an anti-toxin effect on PVL and Hla expression. Few studies have investigated PSMα and Hld expression modulation by antibiotics. Herein, we assessed the effect of antibiotic sub-MIC on PSMα1 and Hld expression for 4 community-acquired methicillin-resistant SA (CA-MRSA), 2 strains belonging to USASA300 and 2 strains belonging to ST80 European clone. SA were grown under oxacillin, clindamycin, linezolid, or tigecycline. After incubation, culture pellets were used for the determination of psmα1, pmtB, pmtR mRNA, and RNAIII levels by relative quantitative RT-PCR. PSMα1 and Hld expressions were measured in supernatant using high-performance-liquid-chromatography coupled to mass-spectrometry (HPLC-MS). Oxacillin sub-MIC reduced PSMα1 and Hld production, partially related to mRNA variations. For other antibiotics, effects on toxin expression were strain or clone dependent. Antibiotic effect on mRNA did not always reflect protein expression modulation. Variations of pmtB, pmtR mRNA, and RNAIII levels were insufficient to explain toxin expression modulation. Altogether, these data indicate that PSMα and Hld expressions are modulated by antibiotics (potential anti-toxin effect of oxacillin) differently compared to PVL and Hla. IMPORTANCE Staphylococcal toxins play an important role in the physiopathology of staphylococcal infections. Subinhibitory concentrations (sub-MIC) of antibiotics modulate in vitro toxins expression in S. aureus: clindamycin (CLI) and linezolid (LIN) display an anti-toxin effect on Panton-Valentine leucocidin and alpha-hemolysin production, while oxacillin (OXA) has an inducing effect. Few studies have focused on the modulation of phenol-soluble modulins alpha (PSMα) including delta-hemolysin expression by sub-MIC antibiotics. The aim of the present study was to investigate the effects of sub-MIC antibiotics on the expression of PSMα toxins for 4 community-acquired methicillin-resistant S. aureus (CA-MRSA) clinical isolates. The data presented herein confirm that OXA sub-MICs constantly inhibit PSMα production for CA-MRSA. Certain strains of S. aureus are highly sensitive to sub-MICs of protein synthesis inhibitory agents, resulting in an important increase of mRNA levels to overcome the intrinsic ribosome blockage ability of these antibiotics, eventually translating in increased expression of toxins.
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28
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Nguyen TH, Cheung GYC, Rigby KM, Kamenyeva O, Kabat J, Sturdevant DE, Villaruz AE, Liu R, Piewngam P, Porter AR, Firdous S, Chiou J, Park MD, Hunt RL, Almufarriji FMF, Tan VY, Asiamah TK, McCausland JW, Fisher EL, Yeh AJ, Bae JS, Kobayashi SD, Wang JM, Barber DL, DeLeo FR, Otto M. Rapid pathogen-specific recruitment of immune effector cells in the skin by secreted toxins. Nat Microbiol 2022; 7:62-72. [PMID: 34873293 PMCID: PMC8732318 DOI: 10.1038/s41564-021-01012-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 10/29/2021] [Indexed: 12/31/2022]
Abstract
Swift recruitment of phagocytic leucocytes is critical in preventing infection when bacteria breach through the protective layers of the skin. According to canonical models, this occurs via an indirect process that is initiated by contact of bacteria with resident skin cells and which is independent of the pathogenic potential of the invader. Here we describe a more rapid mechanism of leucocyte recruitment to the site of intrusion of the important skin pathogen Staphylococcus aureus that is based on direct recognition of specific bacterial toxins, the phenol-soluble modulins (PSMs), by circulating leucocytes. We used a combination of intravital imaging, ear infection and skin abscess models, and in vitro gene expression studies to demonstrate that this early recruitment was dependent on the transcription factor EGR1 and contributed to the prevention of infection. Our findings refine the classical notion of the non-specific and resident cell-dependent character of the innate immune response to bacterial infection by demonstrating a pathogen-specific high-alert mechanism involving direct recruitment of immune effector cells by secreted bacterial products.
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Affiliation(s)
- Thuan H Nguyen
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kevin M Rigby
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Pathogen-Host Cell Biology Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
- miRagen Therapeutics, Inc., Boulder, CO, USA
| | - Olena Kamenyeva
- Biological Imaging Section, Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Juraj Kabat
- Biological Imaging Section, Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Daniel E Sturdevant
- Genomics Unit, Research Technology Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Amer E Villaruz
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ryan Liu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Pipat Piewngam
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Adeline R Porter
- Pathogen-Host Cell Biology Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Saba Firdous
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Chlamydia Pathogenesis Section, NIAID, Bethesda, MD, USA
| | - Janice Chiou
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Graduate School in Biomedical Science, Cedars Sinai Medical Center, Los Angeles, CA, USA
| | - Matthew D Park
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Rachelle L Hunt
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Microbial Pathogenesis Department, Yale University, New Haven, CT, USA
| | - Fawaz M F Almufarriji
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- School of Molecular and Cell Biology, University of Leeds, Leeds, UK
| | - Vee Y Tan
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Tuberculosis Research Section, NIAID, Bethesda, MD, USA
| | - Titus K Asiamah
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Joshua W McCausland
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Johns Hopkins University, Baltimore, MD, USA
| | - Emilie L Fisher
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Vanderbilt University, Nashville, TN, USA
| | - Anthony J Yeh
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- William Carey University College of Osteopathic Medicine, Hattiesburg, MS, USA
| | - Justin S Bae
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Harvard University, Cambridge, MA, USA
| | - Scott D Kobayashi
- Pathogen-Host Cell Biology Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Ji Ming Wang
- Laboratory of Cancer and Immunometabolism, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, USA
| | - Daniel L Barber
- T-Lymphocyte Biology Unit, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Frank R DeLeo
- Pathogen-Host Cell Biology Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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Yang Z, Qiu B, Cheng D, Zhao N, Liu Y, Li M, Liu Q. Virulent Staphylococcus aureus Colonizes Pediatric Nares by Resisting Killing of Human Antimicrobial Peptides. Int J Med Microbiol 2022; 312:151550. [DOI: 10.1016/j.ijmm.2022.151550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 01/16/2022] [Accepted: 01/23/2022] [Indexed: 11/29/2022] Open
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Cheung GYC, Bae JS, Otto M. Pathogenicity and virulence of Staphylococcus aureus. Virulence 2021; 12:547-569. [PMID: 33522395 PMCID: PMC7872022 DOI: 10.1080/21505594.2021.1878688] [Citation(s) in RCA: 485] [Impact Index Per Article: 161.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 01/13/2021] [Accepted: 01/15/2021] [Indexed: 12/15/2022] Open
Abstract
Staphylococcus aureus is one of the most frequent worldwide causes of morbidity and mortality due to an infectious agent. This pathogen can cause a wide variety of diseases, ranging from moderately severe skin infections to fatal pneumonia and sepsis. Treatment of S. aureus infections is complicated by antibiotic resistance and a working vaccine is not available. There has been ongoing and increasing interest in the extraordinarily high number of toxins and other virulence determinants that S. aureus produces and how they impact disease. In this review, we will give an overview of how S. aureus initiates and maintains infection and discuss the main determinants involved. A more in-depth understanding of the function and contribution of S. aureus virulence determinants to S. aureus infection will enable us to develop anti-virulence strategies to counteract the lack of an anti-S. aureus vaccine and the ever-increasing shortage of working antibiotics against this important pathogen.
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Affiliation(s)
- Gordon Y. C. Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, Bethesda, Maryland, USA
| | - Justin S. Bae
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, Bethesda, Maryland, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, Bethesda, Maryland, USA
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Zhou X, Zheng Y, Lv Q, Kong D, Ji B, Han X, Zhou D, Sun Z, Zhu L, Liu P, Jiang H, Jiang Y. Staphylococcus aureus N-terminus formylated δ-toxin tends to form amyloid fibrils, while the deformylated δ-toxin tends to form functional oligomer complexes. Virulence 2021; 12:1418-1437. [PMID: 34028320 PMCID: PMC8158037 DOI: 10.1080/21505594.2021.1928395] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 05/04/2021] [Accepted: 05/07/2021] [Indexed: 11/29/2022] Open
Abstract
The community-associated Methicillin-resistant Staphylococcus aureus strain (CA-MRSA) is highly virulent and has become a major focus of public health professionals. Phenol-soluble modulins (PSM) are key factors in its increased virulence. δ-Toxin belongs to PSM family and has copious secretion in many S. aureus strains. In addition, δ-toxin exists in the S. aureus culture supernatant as both N-terminus formylated δ-toxin (fδ-toxin) and deformylated δ-toxin (dfδ-toxin) groups. Although δ-toxin has been studied for more than 70 years, its functions remain unclear. We isolated and purified PSMs from the supernatant of S. aureus MW2, and found fibrils and oligomers aggregates by Size Exclusion Chromatography. After analyzing PSM aggregates and using peptide simulations, we found that the difference in the monomer structure of fδ-toxin and dfδ-toxin might ultimately lead to differences in the aggregation ability: fδ-toxin and dfδ-toxin tend to form fibrils and oligomers respectively. Of note, we found that fδ-toxin fibrils enhanced the stability of biofilms, while dfδ-toxin oligomers promoted their dispersal. Additionally, oligomeric dfδ-toxin combined with PSMα to form a complex with enhanced functionality. Due to the different aggregation capabilities and functions of fδ-toxin and dfδ-toxin, we speculate that they may be involved in the regulation of physiological activities of S. aureus. Moreover, the dfδ-toxin oligomer not only provides a new form of complex in the study of PSMα, but also has significance as a reference in oligomer research pertaining to some human amyloid diseases.
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Affiliation(s)
- Xinyu Zhou
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Yuling Zheng
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Qingyu Lv
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Decong Kong
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Bin Ji
- Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Xuelian Han
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Zeyu Sun
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Li Zhu
- Beijing Institute of Biotechnology, Beijing, China
| | - Peng Liu
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Hua Jiang
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Yongqiang Jiang
- State Key Laboratory of Pathogens and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
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Damour A, Robin B, Deroche L, Broutin L, Bellin N, Verdon J, Lina G, Leclère FM, Garcia M, Cremniter J, Lévêque N, Bodet C. Phenol-soluble modulins α are major virulence factors of Staphylococcus aureus secretome promoting inflammatory response in human epidermis. Virulence 2021; 12:2474-2492. [PMID: 34516337 PMCID: PMC8451463 DOI: 10.1080/21505594.2021.1975909] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 08/03/2021] [Accepted: 08/25/2021] [Indexed: 11/10/2022] Open
Abstract
Staphylococcus aureus is a skin commensal microorganism commonly colonizing healthy humans. Nevertheless, S. aureus can also be responsible for cutaneous infections and contribute to flare-up of inflammatory skin diseases such as atopic dermatitis (AD), which is characterized by dysbiosis of the skin microbiota with S. aureus as the predominant species. However, the role of major virulence factors of this pathogen such as phenol-soluble modulin (PSM) toxins in epidermal inflammation remains poorly understood. Stimulation of primary human keratinocytes with sublytic concentrations of synthetic and purified PSM α3 resulted in upregulation of a large panel of pro-inflammatory chemokine and cytokine gene expression, including CXCL1, CXCL2, CXCL3, CXCL5, CXCL8, CCL20, IL-1α, IL-1β, IL-6, IL-36γ and TNF-α, while inducing the release of CXCL8, CCL20, TNF-α and IL-6. In addition, using S. aureus culture supernatant from mutants deleted from genes encoding either α-type PSMs or all PSM production, PSMs were shown to be the main factors of S. aureus secretome responsible for pro-inflammatory mediator induction in human keratinocytes. On the other hand, α-type PSM-containing supernatant triggered an intense induction of pro-inflammatory mediator expression and secretion during both topical and basal layer stimulation of an ex vivo model of human skin explants, a physiologically relevant model of pluristratified epidermis. Taken together, the results of this study show that PSMs and more specifically α-type PSMs are major virulence factors of S. aureus inducing a potent inflammatory response during infection of the human epidermis and could thereby contribute to AD flare-up through exacerbation of skin inflammation.
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Affiliation(s)
- Alexia Damour
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
| | - Brandon Robin
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
| | - Luc Deroche
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
| | - Lauranne Broutin
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
- Laboratoire De Bactériologie, CHU de Poitiers, Poitiers, France
| | - Nicolas Bellin
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
| | - Julien Verdon
- Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université De Poitiers, Poitiers, France
| | - Gérard Lina
- CIRI Centre International de Recherche en Infectiologie, Inserm U1111, Université Lyon 1, Ecole Normale Supérieure de Lyon, Lyon, France
- Centre National de Référence des Staphylocoques, Institut des Agent Infectieux, Hôpital de La Croix Rousse, Hospices Civils de Lyon, Lyon, France
| | - Franck Marie Leclère
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
- Département de Chirurgie Plastique, Reconstructive et Esthétique, CHU de Poitiers, Poitiers, France
| | - Magali Garcia
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
- Laboratoire de Virologie et Mycobactériologie, CHU de Poitiers, Poitiers, France
| | - Julie Cremniter
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
- Laboratoire De Bactériologie, CHU de Poitiers, Poitiers, France
| | - Nicolas Lévêque
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
- Laboratoire de Virologie et Mycobactériologie, CHU de Poitiers, Poitiers, France
| | - Charles Bodet
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines EA 4331, Université De Poitiers, Poitiers, France
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Desgranges E, Barrientos L, Herrgott L, Marzi S, Toledo-Arana A, Moreau K, Vandenesch F, Romby P, Caldelari I. The 3'UTR-derived sRNA RsaG coordinates redox homeostasis and metabolism adaptation in response to glucose-6-phosphate uptake in Staphylococcus aureus. Mol Microbiol 2021; 117:193-214. [PMID: 34783400 DOI: 10.1111/mmi.14845] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 11/08/2021] [Accepted: 11/11/2021] [Indexed: 01/28/2023]
Abstract
Staphylococcus aureus RsaG is a 3'-untranslated region (3'UTR) derived sRNA from the conserved uhpT gene encoding a glucose-6-phosphate (G6P) transporter expressed in response to extracellular G6P. The transcript uhpT-RsaG undergoes degradation from 5'- to 3'-end by the action of the exoribonucleases J1/J2, which are blocked by a stable hairpin structure at the 5'-end of RsaG, leading to its accumulation. RsaG together with uhpT is induced when bacteria are internalized into host cells or in the presence of mucus-secreting cells. Using MS2-affinity purification coupled with RNA sequencing, several RNAs were identified as targets including mRNAs encoding the transcriptional factors Rex, CcpA, SarA, and the sRNA RsaI. Our data suggested that RsaG contributes to the control of redox homeostasis and adjusts metabolism to changing environmental conditions. RsaG uses different molecular mechanisms to stabilize, degrade, or repress the translation of its mRNA targets. Although RsaG is conserved only in closely related species, the uhpT 3'UTR of the ape pathogen S. simiae harbors an sRNA, whose sequence is highly different, and which does not respond to G6P levels. Our results hypothesized that the 3'UTRs from UhpT transporter encoding mRNAs could have rapidly evolved to enable adaptation to host niches.
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Affiliation(s)
- Emma Desgranges
- Architecture et Réactivité de l'ARN, UPR9002, CNRS, Université de Strasbourg, Strasbourg, France
| | - Laura Barrientos
- Architecture et Réactivité de l'ARN, UPR9002, CNRS, Université de Strasbourg, Strasbourg, France
| | - Lucas Herrgott
- Architecture et Réactivité de l'ARN, UPR9002, CNRS, Université de Strasbourg, Strasbourg, France
| | - Stefano Marzi
- Architecture et Réactivité de l'ARN, UPR9002, CNRS, Université de Strasbourg, Strasbourg, France
| | | | - Karen Moreau
- CIRI, Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, École Normale Supérieure de Lyon, Hospices Civils de Lyon, Université de Lyon, Lyon, France
| | - François Vandenesch
- CIRI, Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, École Normale Supérieure de Lyon, Hospices Civils de Lyon, Université de Lyon, Lyon, France
| | - Pascale Romby
- Architecture et Réactivité de l'ARN, UPR9002, CNRS, Université de Strasbourg, Strasbourg, France
| | - Isabelle Caldelari
- Architecture et Réactivité de l'ARN, UPR9002, CNRS, Université de Strasbourg, Strasbourg, France
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Kawada-Matsuo M, Le MNT, Komatsuzawa H. Antibacterial Peptides Resistance in Staphylococcus aureus: Various Mechanisms and the Association with Pathogenicity. Genes (Basel) 2021; 12:genes12101527. [PMID: 34680923 PMCID: PMC8535901 DOI: 10.3390/genes12101527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 01/15/2023] Open
Abstract
Staphylococcus aureus is a bacterium that mainly colonizes the nasal cavity and skin. To colonize the host, it is necessary for S. aureus to resist many antibacterial factors derived from human and commensal bacteria. Among them are the bacteria-derived antimicrobial peptides (AMPs) called bacteriocins. It was reported that some two-component systems (TCSs), which are signal transduction systems specific to bacteria, are involved in the resistance to several bacteriocins in S. aureus. However, the TCS-mediated resistance is limited to relatively low concentrations of bacteriocins, while high concentrations of bacteriocins still exhibit antibacterial activity against S. aureus. To determine whether we could obtain highly bacteriocin-resistant mutants, we tried to isolate highly nisin A-resistant mutants by exposing the cells to sub-minimum inhibitory concentrations (MICs) of nisin A. Nisin A is one of the bacteriocins produced by Lactococcus lactis and is utilized as a food preservative worldwide. Finally, we obtained highly nisin A-resistant mutants with mutations in one TCS, BraRS, and in PmtR, which is involved in the expression of pmtABCD. Notably, some highly resistant strains also showed increased pathogenicity. Based on our findings, this review provides up-to-date information on the role of TCSs in the susceptibility to antibacterial peptides. Additionally, the mechanism for high antimicrobial peptides resistance and its association with pathogenicity in S. aureus is elucidated.
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Warrier A, Satyamoorthy K, Murali TS. Quorum-sensing regulation of virulence factors in bacterial biofilm. Future Microbiol 2021; 16:1003-1021. [PMID: 34414776 DOI: 10.2217/fmb-2020-0301] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Chronic polymicrobial wound infections are often characterized by the presence of bacterial biofilms. They show considerable structural and functional heterogeneity, which influences the choice of antimicrobial therapy and wound healing dynamics. The hallmarks of biofilm-associated bacterial infections include elevated antibiotic resistance and extreme pathogenicity. Biofilm helps bacteria to evade the host defense mechanisms and persist longer in the host. Quorum-sensing (QS)-mediated cell signaling primarily regulates biofilm formation in chronic infections and plays a major role in eliciting virulence. This review focuses on the QS mechanisms of two major bacterial pathogens, Staphylococcus aureus and Pseudomonas aeruginosa and explains how they interact in the wound microenvironment to regulate biofilm development and virulence. The review also provides an insight into the treatment modalities aimed at eradicating polymicrobial biofilms. This information will help us develop better diagnostic modalities and devise effective treatment regimens to successfully manage and overcome severe life-threatening bacterial infections.
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Affiliation(s)
- Anjali Warrier
- Department of Biotechnology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Kapaettu Satyamoorthy
- Department of Cell & Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Thokur Sreepathy Murali
- Department of Biotechnology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India.,Manipal Center for Infectious Diseases (MAC ID), Prasanna School of Public Health, Manipal Academy of Higher Education, Manipal, Karnataka, India
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36
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Hommes JW, Kratofil RM, Wahlen S, de Haas CJC, Hildebrand RB, Hovingh GK, Otto M, van Eck M, Hoekstra M, Korporaal SJA, Surewaard BGJ. High density lipoproteins mediate in vivo protection against staphylococcal phenol-soluble modulins. Sci Rep 2021; 11:15357. [PMID: 34321507 PMCID: PMC8319287 DOI: 10.1038/s41598-021-94651-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 06/28/2021] [Indexed: 12/30/2022] Open
Abstract
Staphylococcus aureus virulence has been associated with the production of phenol-soluble modulins (PSMs). These PSMs have distinct virulence functions and are known to activate, attract and lyse neutrophils. These PSM-associated biological functions are inhibited by lipoproteins in vitro. We set out to address whether lipoproteins neutralize staphylococcal PSM-associated virulence in experimental animal models. Serum from both LCAT an ABCA1 knockout mice strains which are characterised by near absence of high-density lipoprotein (HDL) levels, was shown to fail to protect against PSM-induced neutrophil activation and lysis in vitro. Importantly, PSM-induced peritonitis in LCAT-/- mice resulted in increased lysis of resident peritoneal macrophages and enhanced neutrophil recruitment into the peritoneal cavity. Notably, LCAT-/- mice were more likely to succumb to staphylococcal bloodstream infections in a PSM-dependent manner. Plasma from homozygous carriers of ABCA1 variants characterized by very low HDL-cholesterol levels, was found to be less protective against PSM-mediated biological functions compared to healthy humans. Therefore, we conclude that lipoproteins present in blood can protect against staphylococcal PSMs, the key virulence factor of community-associated methicillin resistant S. aureus.
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Affiliation(s)
- Josefien W Hommes
- Department of Microbiology, Immunology, and Infectious Disease. Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Rachel M Kratofil
- Department of Microbiology, Immunology, and Infectious Disease. Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Sigrid Wahlen
- Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands.,Department of Diagnostic Sciences, Laboratory of Experimental Immunology, Ghent University, Ghent, Belgium
| | - Carla J C de Haas
- Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Reeni B Hildebrand
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Gorlaeus Laboratories, Leiden, The Netherlands
| | - G Kees Hovingh
- Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Micheal Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Miranda van Eck
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Gorlaeus Laboratories, Leiden, The Netherlands
| | - Menno Hoekstra
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Gorlaeus Laboratories, Leiden, The Netherlands
| | - Suzanne J A Korporaal
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Gorlaeus Laboratories, Leiden, The Netherlands.,Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bas G J Surewaard
- Department of Microbiology, Immunology, and Infectious Disease. Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada. .,Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands.
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Matilla-Cuenca L, Toledo-Arana A, Valle J. Anti-Biofilm Molecules Targeting Functional Amyloids. Antibiotics (Basel) 2021; 10:antibiotics10070795. [PMID: 34210036 PMCID: PMC8300730 DOI: 10.3390/antibiotics10070795] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 12/18/2022] Open
Abstract
The choice of an effective therapeutic strategy in the treatment of biofilm-related infections is a significant issue. Amyloids, which have been historically related to human diseases, are now considered to be prevailing structural components of the biofilm matrix in a wide range of bacteria. This assumption creates the potential for an exciting research area, in which functional amyloids are considered to be attractive targets for drug development to dissemble biofilm structures. The present review describes the best-characterized bacterial functional amyloids and focuses on anti-biofilm agents that target intrinsic and facultative amyloids. This study provides a better understanding of the different modes of actions of the anti-amyloid molecules to inhibit biofilm formation. This information can be further exploited to improve the therapeutic strategies to combat biofilm-related infections.
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Wang X, Koffi PF, English OF, Lee JC. Staphylococcus aureus Extracellular Vesicles: A Story of Toxicity and the Stress of 2020. Toxins (Basel) 2021; 13:toxins13020075. [PMID: 33498438 PMCID: PMC7909408 DOI: 10.3390/toxins13020075] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 12/22/2022] Open
Abstract
Staphylococcus aureus generates and releases extracellular vesicles (EVs) that package cytosolic, cell-wall associated, and membrane proteins, as well as glycopolymers and exoproteins, including alpha hemolysin, leukocidins, phenol-soluble modulins, superantigens, and enzymes. S. aureus EVs, but not EVs from pore-forming toxin-deficient strains, were cytolytic for a variety of mammalian cell types, but EV internalization was not essential for cytotoxicity. Because S. aureus is subject to various environmental stresses during its encounters with the host during infection, we assessed how these exposures affected EV production in vitro. Staphylococci grown at 37 °C or 40 °C did not differ in EV production, but cultures incubated at 30 °C yielded more EVs when grown to the same optical density. S. aureus cultivated in the presence of oxidative stress, in iron-limited media, or with subinhibitory concentrations of ethanol, showed greater EV production as determined by protein yield and quantitative immunoblots. In contrast, hyperosmotic stress or subinhibitory concentrations of erythromycin reduced S. aureus EV yield. EVs represent a novel S. aureus secretory system that is affected by a variety of stress responses and allows the delivery of biologically active pore-forming toxins and other virulence determinants to host cells.
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39
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Zaman M, Andreasen M. Modulating Kinetics of the Amyloid-Like Aggregation of S. aureus Phenol-Soluble Modulins by Changes in pH. Microorganisms 2021; 9:microorganisms9010117. [PMID: 33430169 PMCID: PMC7825627 DOI: 10.3390/microorganisms9010117] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 12/30/2020] [Accepted: 01/04/2021] [Indexed: 11/26/2022] Open
Abstract
The pathogen Staphylococcus aureus is recognized as one of the most frequent causes of biofilm-associated infections. The recently identified phenol-soluble modulin (PSM) peptides act as the key molecular effectors of staphylococcal biofilm maturation and promote the formation of an aggregated fibril structure. The aim of this study was to evaluate the effect of various pH values on the formation of functional amyloids of individual PSM peptides. Here, we combined a range of biophysical, chemical kinetics and microscopic techniques to address the structure and aggregation mechanism of individual PSMs under different conditions. We established that there is a pH-induced switch in PSM aggregation kinetics. Different lag times and growth of fibrils were observed, which indicates that there was no clear correlation between the rates of fibril elongation among different PSMs. This finding confirms that pH can modulate the aggregation properties of these peptides and suggest a deeper understanding of the formation of aggregates, which represents an important basis for strategies to interfere and might help in reducing the risk of biofilm-related infections.
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40
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Secretion of and Self-Resistance to the Novel Fibupeptide Antimicrobial Lugdunin by Distinct ABC Transporters in Staphylococcus lugdunensis. Antimicrob Agents Chemother 2020; 65:AAC.01734-20. [PMID: 33106269 PMCID: PMC7927808 DOI: 10.1128/aac.01734-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/15/2020] [Indexed: 02/01/2023] Open
Abstract
Lugdunin is the first reported nonribosomally synthesized antibiotic from human microbiomes. Its production by the commensal Staphylococcus lugdunensis eliminates the pathogen Staphylococcus aureus from human nasal microbiomes. The cycloheptapeptide lugdunin is the founding member of the new class of fibupeptide antibiotics, which have a novel mode of action and represent promising new antimicrobial agents. How S. lugdunensis releases and achieves producer self-resistance to lugdunin has remained unknown. We report that two ABC transporters encoded upstream of the lugdunin-biosynthetic operon have distinct yet overlapping roles in lugdunin secretion and self-resistance. While deletion of the lugEF transporter genes abrogated most of the lugdunin secretion, the lugGH transporter genes had a dominant role in resistance. Yet all four genes were required for full-level lugdunin resistance. The small accessory putative membrane protein LugI further contributed to lugdunin release and resistance levels conferred by the ABC transporters. Whereas LugIEFGH also conferred resistance to lugdunin congeners with inverse structures or with amino acid exchange at position 6, they neither affected the susceptibility to a lugdunin variant with an exchange at position 2 nor to other cyclic peptide antimicrobials such as daptomycin or gramicidin S. The obvious selectivity of the resistance mechanism raises hopes that it will not confer cross-resistance to other antimicrobials or to optimized lugdunin derivatives to be used for the prevention and treatment of S. aureus infections.
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Emerging Roles of Functional Bacterial Amyloids in Gene Regulation, Toxicity, and Immunomodulation. Microbiol Mol Biol Rev 2020; 85:85/1/e00062-20. [PMID: 33239434 DOI: 10.1128/mmbr.00062-20] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacteria often reside in multicellular communities, called biofilms, held together by an extracellular matrix. In many bacteria, the major proteinaceous component of the biofilm are amyloid fibers. Amyloids are highly stable and structured protein aggregates which were known mostly to be associated with neurodegenerative diseases, such as Alzheimer's, Parkinson's, and Huntington's diseases. In recent years, microbial amyloids were identified also in other species and shown to play major roles in microbial physiology and virulence. For example, amyloid fibers assemble on the bacterial cell surface as a part of the extracellular matrix and are extremely important to the scaffolding and structural integrity of biofilms, which contribute to microbial resilience and resistance. Furthermore, microbial amyloids play fundamental nonscaffold roles that contribute to the development of biofilms underlying numerous persistent infections. Here, we review several nonscaffold roles of bacterial amyloid proteins, including bridging cells during collective migration, acting as regulators of cell fate, as toxins against other bacteria or against host immune cells, and as modulators of the hosts' immune system. These overall points on the complexity of the amyloid fold in encoding numerous activities, which offer approaches for the development of a novel repertoire of antivirulence therapeutics.
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Vlaeminck J, Raafat D, Surmann K, Timbermont L, Normann N, Sellman B, van Wamel WJB, Malhotra-Kumar S. Exploring Virulence Factors and Alternative Therapies against Staphylococcus aureus Pneumonia. Toxins (Basel) 2020; 12:toxins12110721. [PMID: 33218049 PMCID: PMC7698915 DOI: 10.3390/toxins12110721] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/12/2020] [Accepted: 11/15/2020] [Indexed: 12/13/2022] Open
Abstract
Pneumonia is an acute pulmonary infection associated with high mortality and an immense financial burden on healthcare systems. Staphylococcus aureus is an opportunistic pathogen capable of inducing S. aureus pneumonia (SAP), with some lineages also showing multidrug resistance. Given the high level of antibiotic resistance, much research has been focused on targeting S. aureus virulence factors, including toxins and biofilm-associated proteins, in an attempt to develop effective SAP therapeutics. Despite several promising leads, many hurdles still remain for S. aureus vaccine research. Here, we review the state-of-the-art SAP therapeutics, highlight their pitfalls, and discuss alternative approaches of potential significance and future perspectives.
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Affiliation(s)
- Jelle Vlaeminck
- Laboratory of Medical Microbiology, Vaccine and Infectious Diseases Institute, University of Antwerp, 2610 Antwerp, Belgium; (J.V.); (L.T.)
| | - Dina Raafat
- Department of Immunology, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, 17475 Greifswald, Germany; (D.R.); (N.N.)
- Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, Alexandria 21521, Egypt
| | - Kristin Surmann
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, 17475 Greifswald, Germany;
| | - Leen Timbermont
- Laboratory of Medical Microbiology, Vaccine and Infectious Diseases Institute, University of Antwerp, 2610 Antwerp, Belgium; (J.V.); (L.T.)
| | - Nicole Normann
- Department of Immunology, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, 17475 Greifswald, Germany; (D.R.); (N.N.)
| | - Bret Sellman
- Microbiome Discovery, Microbial Sciences, BioPharmaceuticals R & D, AstraZeneca, Gaithersburg, MD 20878, USA;
| | - Willem J. B. van Wamel
- Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center Rotterdam, 3015 Rotterdam, The Netherlands;
| | - Surbhi Malhotra-Kumar
- Laboratory of Medical Microbiology, Vaccine and Infectious Diseases Institute, University of Antwerp, 2610 Antwerp, Belgium; (J.V.); (L.T.)
- Correspondence: ; Tel.: +32-3-265-27-52
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Zeytuni N, Dickey SW, Hu J, Chou HT, Worrall LJ, Alexander JAN, Carlson ML, Nosella M, Duong F, Yu Z, Otto M, Strynadka NCJ. Structural insight into the Staphylococcus aureus ATP-driven exporter of virulent peptide toxins. SCIENCE ADVANCES 2020; 6:eabb8219. [PMID: 32998902 PMCID: PMC7527219 DOI: 10.1126/sciadv.abb8219] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 08/14/2020] [Indexed: 06/06/2023]
Abstract
Staphylococcus aureus is a major human pathogen that has acquired alarming broad-spectrum antibiotic resistance. One group of secreted toxins with key roles during infection is the phenol-soluble modulins (PSMs). PSMs are amphipathic, membrane-destructive cytolytic peptides that are exported to the host-cell environment by a designated adenosine 5'-triphosphate (ATP)-binding cassette (ABC) transporter, the PSM transporter (PmtABCD). Here, we demonstrate that the minimal Pmt unit necessary for PSM export is PmtCD and provide its first atomic characterization by single-particle cryo-EM and x-ray crystallography. We have captured the transporter in the ATP-bound state at near atomic resolution, revealing a type II ABC exporter fold, with an additional cytosolic domain. Comparison to a lower-resolution nucleotide-free map displaying an "open" conformation and putative hydrophobic inner chamber of a size able to accommodate the binding of two PSM peptides provides mechanistic insight and sets the foundation for therapeutic design.
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Affiliation(s)
- N. Zeytuni
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - S. W. Dickey
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - J. Hu
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - H. T. Chou
- CryoEM Shared Resources, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - L. J. Worrall
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
- High Resolution Macromolecular Cryo-Electron Microscopy facility, University of British Columbia, Vancouver, V6T 1Z3, BC, Canada
| | - J. A. N. Alexander
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - M. L. Carlson
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - M. Nosella
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - F. Duong
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
| | - Z. Yu
- CryoEM Shared Resources, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - M. Otto
- CryoEM Shared Resources, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - N. C. J. Strynadka
- Department of Biochemistry and Molecular Biology and the Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
- High Resolution Macromolecular Cryo-Electron Microscopy facility, University of British Columbia, Vancouver, V6T 1Z3, BC, Canada
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44
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Butrico CE, Cassat JE. Quorum Sensing and Toxin Production in Staphylococcus aureus Osteomyelitis: Pathogenesis and Paradox. Toxins (Basel) 2020; 12:toxins12080516. [PMID: 32806558 PMCID: PMC7471978 DOI: 10.3390/toxins12080516] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 08/04/2020] [Accepted: 08/10/2020] [Indexed: 01/18/2023] Open
Abstract
Staphylococcus aureus is a Gram-positive pathogen capable of infecting nearly every vertebrate organ. Among these tissues, invasive infection of bone (osteomyelitis) is particularly common and induces high morbidity. Treatment of osteomyelitis is notoriously difficult and often requires debridement of diseased bone in conjunction with prolonged antibiotic treatment to resolve infection. During osteomyelitis, S. aureus forms characteristic multicellular microcolonies in distinct niches within bone. Virulence and metabolic responses within these multicellular microcolonies are coordinated, in part, by quorum sensing via the accessory gene regulator (agr) locus, which allows staphylococcal populations to produce toxins and adapt in response to bacterial density. During osteomyelitis, the Agr system significantly contributes to dysregulation of skeletal homeostasis and disease severity but may also paradoxically inhibit persistence in the host. Moreover, the Agr system is subject to complex crosstalk with other S. aureus regulatory systems, including SaeRS and SrrAB, which can significantly impact the progression of osteomyelitis. The objective of this review is to highlight Agr regulation, its implications on toxin production, factors that affect Agr activation, and the potential paradoxical influences of Agr regulation on disease progression during osteomyelitis.
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Affiliation(s)
- Casey E. Butrico
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
| | - James E. Cassat
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation (VI4), Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Correspondence: ; Tel.: +1-615-936-6494
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45
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Song HS, Choi TR, Han YH, Park YL, Park JY, Yang SY, Bhatia SK, Gurav R, Kim YG, Kim JS, Joo HS, Yang YH. Increased resistance of a methicillin-resistant Staphylococcus aureus Δagr mutant with modified control in fatty acid metabolism. AMB Express 2020; 10:64. [PMID: 32266584 PMCID: PMC7138893 DOI: 10.1186/s13568-020-01000-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 03/28/2020] [Indexed: 02/08/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) strains are distinct from general Staphylococcus strains with respect to the composition of the membrane, ability to form a thicker biofilm, and, importantly, ability to modify the target of antibiotics to evade their activity. The agr gene is an accessory global regulator of gram-positive bacteria that governs virulence or resistant mechanisms and therefore an important target for the control of resistant strains. However, the mechanism by which agr impacts resistance to β-lactam antibiotics remains unclear. In the present study, we found the Δagr mutant strain having higher resistance to high concentrations of β-lactam antibiotics such as oxacillin and ampicillin. To determine the influence of variation in the microenvironment of cells between the parental and mutant strains, fatty acid analysis of the supernatant, total lipids, and phospholipid fatty acids were compared. The Δagr mutant strain tended to produce fewer fatty acids and retained lower amounts of C16, C18 fatty acids in the supernatant. Phospholipid analysis showed a dramatic increase in the hydrophobic longer-chain fatty acids in the membrane. To target membrane, we applied several surfactants and found that sorbitan monolaurate (Span20) had a synergistic effect with oxacillin by decreasing biofilm formation and growth. These findings indicate that agr deletion allows for MRSA to resist antibiotics via several changes including constant expression of mecA, fatty acid metabolism, and biofilm thickening.
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Staphylococcus aureus Virulence Affected by an Alternative Nisin A Resistance Mechanism. Appl Environ Microbiol 2020; 86:AEM.02923-19. [PMID: 32086306 DOI: 10.1128/aem.02923-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 02/04/2020] [Indexed: 01/25/2023] Open
Abstract
Nisin A is a bacteriocin produced by Lactococcus lactis and is widely used as a food preservative. Staphylococcus aureus has the BraRS-VraDE system that provides resistance against low concentrations of nisin A. BraRS is a two-component system that induces the expression of the ABC transporter VraDE. Previously, we isolated a highly nisin A-resistant strain with increased VraDE expression due to a mutation in braRS In this study, we isolated S. aureus MW2 mutants with BraRS-VraDE-independent nisin A resistance. These mutants, designated SAN2 ( S. aureus nisin resistant) and SAN469, had a mutation in pmtR, which encodes a transcriptional regulator responsible for the expression of the pmtABCD operon. As a result, these mutants exhibited increased expression of PmtABCD, a transporter responsible for the export of phenol-soluble modulin (PSM). Characterization of the mutants revealed that they have decreased susceptibility to human β-defensin-3 (hBD3) and LL37, which are innate immune factors. Additionally, these mutants showed higher hemolytic activity than the original MW2 strain. Furthermore, in a mouse bacteremia model, the SAN2 strain exhibited a lower survival rate than the original MW2 strain. These results indicate that the increased expression of pmtABCD due to a pmtR mutation is an alternative nisin A resistance mechanism that also affects virulence in S. aureus IMPORTANCE Recently, the emergence of antibiotic-resistant bacteria has resulted in serious problems for chemotherapy. In addition, many antibacterial agents, such as disinfectants and food additives, are widely used. Therefore, there is a possibility that bacteria are becoming resistant to some antibacterial agents. In this study, we investigated whether Staphylococcus aureus can become resistant to nisin A, one of the bacteriocins applied as a food additive. We isolated a highly nisin A-resistant strain designated SAN2 that displayed increased expression of Pmt proteins, which are involved in the secretion of virulence factors called phenol-soluble modulins (PSMs). This strain also showed decreased susceptibility to human antimicrobial peptides and increased hemolytic activity. In addition, SAN2 showed increased lethal activity in a mouse bacteremia model. Our study provides new insights into the possibility that the acquisition of resistance against food preservatives may modulate virulence in S. aureus, suggesting that we need to pay more attention to the use of food preservatives together with antibiotics.
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Lin A, Liu Y, Zhu X, Chen X, Liu J, Zhou Y, Qin X, Liu J. Bacteria-Responsive Biomimetic Selenium Nanosystem for Multidrug-Resistant Bacterial Infection Detection and Inhibition. ACS NANO 2019; 13:13965-13984. [PMID: 31730327 DOI: 10.1021/acsnano.9b05766] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Multidrug-resistant (MDR) bacterial infections are a severe threat to public health owing to their high risk of fatality. Noticeably, the premature degradation and undeveloped imaging ability of antibiotics still remain challenging. Herein, a selenium nanosystem in response to a bacteria-infected microenvironment is proposed as an antibiotic substitute to detect and inhibit methicillin-resistant Staphylococcus aureus (MRSA) with a combined strategy. Using natural red blood cell membrane (RBCM) and bacteria-responsive gelatin nanoparticles (GNPs), the Ru-Se@GNP-RBCM nanosystem was constructed for effective delivery of Ru-complex-modified selenium nanoparticles (Ru-Se NPs). Taking advantage of natural RBCM, the immune system clearance was reduced and exotoxins were neutralized efficiently. GNPs could be degraded by gelatinase in pathogen-infected areas in situ; therefore, Ru-Se NPs were released to destroy the bacteria cells. Ru-Se NPs with intense fluorescence imaging capability could accurately monitor the infection treatment process. Moreover, excellent in vivo bacteria elimination and a facilitated wound healing process were confirmed by two kinds of MRSA-infected mice models. Overall, the above advantages proved that the prepared nanosystem is a promising antibiotic alternative to combat the ever-threatening multidrug-resistant bacteria.
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Affiliation(s)
- Ange Lin
- Department of Chemistry , Jinan University , Guangzhou 510632 , China
| | - Yanan Liu
- Department of Chemistry , Jinan University , Guangzhou 510632 , China
- College of Life Sciences , Shenzhen University , Shenzhen , Guangdong 518060 , China
| | - Xufeng Zhu
- Department of Chemistry , Jinan University , Guangzhou 510632 , China
| | - Xu Chen
- Department of Chemistry , Jinan University , Guangzhou 510632 , China
| | - Jiawei Liu
- Department of Chemistry , Jinan University , Guangzhou 510632 , China
| | - Yanhui Zhou
- Department of Chemistry , Jinan University , Guangzhou 510632 , China
| | - Xiuying Qin
- Department of Chemistry , Jinan University , Guangzhou 510632 , China
| | - Jie Liu
- Department of Chemistry , Jinan University , Guangzhou 510632 , China
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Subramanian D, Bhasuran B, Natarajan J. Genomic analysis of RNA-Seq and sRNA-Seq data identifies potential regulatory sRNAs and their functional roles in Staphylococcus aureus. Genomics 2019; 111:1431-1446. [DOI: 10.1016/j.ygeno.2018.09.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 09/21/2018] [Accepted: 09/26/2018] [Indexed: 12/17/2022]
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George SE, Hrubesch J, Breuing I, Vetter N, Korn N, Hennemann K, Bleul L, Willmann M, Ebner P, Götz F, Wolz C. Oxidative stress drives the selection of quorum sensing mutants in the Staphylococcus aureus population. Proc Natl Acad Sci U S A 2019; 116:19145-19154. [PMID: 31488708 PMCID: PMC6754547 DOI: 10.1073/pnas.1902752116] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Quorum sensing (QS) is the central mechanism by which social interactions within the bacterial community control bacterial behavior. QS-negative cells benefit by exploiting public goods produced by the QS-proficient population. Mechanisms to keep the balance between producers and nonproducers within the population are expected but have not been elucidated for peptide-based QS systems in gram-positive pathogens. The Agr system of Staphylococcus aureus comprises the secretion and sensing of an autoinducing peptide to activate its own expression via the response regulator AgrA as well as the expression of a regulatory RNAIII and psmα/psmß coding for phenol-soluble modulins (PSMs). Agr mutants can be monitored on blood agar due to their nonhemolytic phenotype. In vitro evolution and competition experiments show that they readily accumulate in a process that is accelerated by ciprofloxacin, while the wild type (WT) is retained in the population at low numbers. However, agr mutants possess a fitness advantage only under aerobic conditions. Under hypoxia, Agr activity is increased but without the expected fitness cost. The Agr-imposed oxygen-dependent fitness cost is not due to a metabolic burden but due to the reactive oxygen species (ROS)-inducing capacity of the PSMs and RNAIII-regulated factors. Thus, selection of mutants is dictated by the QS system itself. Under aerobic conditions, emergence of agr-negative mutants may provide the population with a fitness advantage while hypoxia favors QS maintenance and even affords increased toxin production. The oxygen-driven tuning of the Agr system might be of importance to provide the pathogen with capabilities crucial for disease progression.
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Affiliation(s)
- Shilpa Elizabeth George
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Jennifer Hrubesch
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Inga Breuing
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Naisa Vetter
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Natalya Korn
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Katja Hennemann
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Lisa Bleul
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Matthias Willmann
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Patrick Ebner
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Friedrich Götz
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
| | - Christiane Wolz
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen 72076, Germany
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Broad and Effective Protection against Staphylococcus aureus Is Elicited by a Multivalent Vaccine Formulated with Novel Antigens. mSphere 2019; 4:4/5/e00362-19. [PMID: 31484738 PMCID: PMC6731528 DOI: 10.1128/msphere.00362-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The demand for a prophylactic vaccine against methicillin-resistant Staphylococcus aureus (MRSA) has motivated numerous dedicated research groups to design and develop such a vaccine. In this study, we have developed a multivalent vaccine, Sta-V5, composed of five conserved antigens involved in three important virulence mechanisms. This prototype vaccine conferred up to 100% protection against multiple epidemiologically relevant S. aureus isolates in five different murine disease models. The vaccine not only elicits functional antibodies that mediate opsonophagocytic killing of S. aureus but also mounts robust antigen-specific T-cell responses. In addition, our data implied that γδ T cells contribute to the protection induced by Sta-V5 in a murine skin infection model.IMPORTANCE Staphylococcus aureus infections, especially MRSA infections, are becoming a major global health issue and are resulting in mortality rates that are increasing every year. However, an effective vaccine is lacking due to the complexity of the infection process of S. aureus In this study, we found that the addition of two novel protein components to three well-studied vaccine candidates significantly improved the efficacy of the combined vaccine. Furthermore, the five-component vaccine not only elicits a robust antibody response but also induces cytokine secretion by T cells, making it a promising vaccine candidate to fill the void.
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