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Vinodhini V, Kavitha M. Deciphering agr quorum sensing in Staphylococcus aureus: insights and therapeutic prospects. Mol Biol Rep 2024; 51:155. [PMID: 38252331 DOI: 10.1007/s11033-023-08930-3] [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: 08/01/2023] [Accepted: 10/10/2023] [Indexed: 01/23/2024]
Abstract
The emergence of superbugs like methicillin-resistant Staphylococcus aureus exposed the limitations of treating microbial infections using antibiotics. At present, the discovery of novel and convincing therapeutic methods are being executed increasingly as possible substitutes to conventional antibiotic therapies. The quorum sensing helps Staphylococcus aureus become more viable through their signaling mechanisms. In recent years, targeting the prominent factors of quorum sensing has obtained remarkable attention as a futuristic approach to dealing with bacterial pathogenicity. The standard antibiotic therapy intends to inhibit the organism by targeting specific molecules and afford a chance for the evolution of antibiotic resistance. This prompts the development of novel therapeutic strategies like inhibiting quorum sensing that can limit bacterial virulence by decreasing the selective pressure, thereby restricting antibiotic resistance evolution. This review furnishes new insights into the accessory gene regulator quorum sensing in Staphylococcus aureus and its inhibition by targeting the genes that regulate the operon. Further, this review comprehensively explores the inhibitors reported up to date and their specific targets and discusses their potentially ineffective alternative therapy against methicillin-resistant Staphylococcus aureus.
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Affiliation(s)
- V Vinodhini
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - M Kavitha
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India.
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2
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Tölken LA, Wassilew GI, Grolimund D, Weitkamp T, Hesse B, Rakow A, Siemens N, Schoon J. Cobalt and Chromium Ions Impair Macrophage Response to Staphylococcus aureus Infection. ACS Biomater Sci Eng 2024; 10:563-574. [PMID: 38108141 DOI: 10.1021/acsbiomaterials.3c01031] [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] [Indexed: 12/19/2023]
Abstract
Cobalt-chromium-molybdenum (CoCrMo) alloys are routinely used in arthroplasty. CoCrMo wear particles and ions derived from arthroplasty implants lead to macrophage-driven adverse local tissue reactions, which have been linked to an increased risk of periprosthetic joint infection after revision arthroplasty. While metal-induced cytotoxicity is well characterized in human macrophages, direct effects on their functionality have remained elusive. Synchrotron radiation X-ray microtomography and X-ray fluorescence mapping indicated that peri-implant tissues harvested during aseptic revision of different arthroplasty implants are exposed to Co and Cr in situ. Confocal laser scanning microscopy revealed that macrophage influx is predominant in patient tissue. While in vitro exposure to Cr3+ had only minor effects on monocytes/macrophage phenotype, pathologic concentrations of Co2+ significantly impaired both, monocyte/macrophage phenotype and functionality. High concentrations of Co2+ led to a shift in macrophage subsets and loss of surface markers, including CD14 and CD16. Both Co2+ and Cr3+ impaired macrophage responses to Staphylococcus aureus infection, and particularly, Co2+-exposed macrophages showed decreased phagocytic activity. These findings demonstrate the immunosuppressive effects of locally elevated metal ions on the innate immune response and support further investigations, including studies exploring whether Co2+ and Cr3+ or CoCrMo alloys per se expose the patients to a higher risk of infections post-revision arthroplasty.
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Affiliation(s)
- Lea A Tölken
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald 17489,Germany
| | - Georgi I Wassilew
- Center for Orthopaedics, Trauma Surgery and Rehabilitation Medicine, University Medicine Greifswald, Greifswald 17475, Germany
| | - Daniel Grolimund
- Swiss Light Source, Paul Scherrer Institute, Villigen-PSI 5232, Switzerland
| | | | - Bernhard Hesse
- Xploraytion GmbH, Berlin 10625, Germany
- ESRF-The European Synchrotron, Grenoble 38000, France
| | - Anastasia Rakow
- Center for Orthopaedics, Trauma Surgery and Rehabilitation Medicine, University Medicine Greifswald, Greifswald 17475, Germany
| | - Nikolai Siemens
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald 17489,Germany
| | - Janosch Schoon
- Center for Orthopaedics, Trauma Surgery and Rehabilitation Medicine, University Medicine Greifswald, Greifswald 17475, Germany
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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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Williams P, Hill P, Bonev B, Chan WC. Quorum-sensing, intra- and inter-species competition in the staphylococci. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001381. [PMID: 37578829 PMCID: PMC10482373 DOI: 10.1099/mic.0.001381] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/31/2023] [Indexed: 08/15/2023]
Abstract
In Gram-positive bacteria such as Staphylococcus aureus and the coagulase-negative staphylococci (CoNS), the accessory gene regulator (agr) is a highly conserved but polymorphic quorum-sensing system involved in colonization, virulence and biofilm development. Signalling via agr depends on the interaction of an autoinducing peptide (AIP) with AgrC, a transmembrane sensor kinase that, once phosphorylated activates the response regulator AgrA. This in turn autoinduces AIP biosynthesis and drives target gene expression directly via AgrA or via the post-transcriptional regulator, RNAIII. In this review we describe the molecular mechanisms underlying the agr-mediated generation of, and response to, AIPs and the molecular basis of AIP-dependent activation and inhibition of AgrC. How the environment impacts on agr functionality is considered and the consequences of agr dysfunction for infection explored. We also discuss the concept of AIP-driven competitive interference between S. aureus and the CoNS and its anti-infective potential.
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Affiliation(s)
- Paul Williams
- Biodiscovery Institute and School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Phil Hill
- School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough, LE12 5RD, UK
| | - Boyan Bonev
- Biodiscovery Institute and School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Weng C. Chan
- School of Pharmacy, Biodiscovery Institute, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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Shumba P, Sura T, Moll K, Chakrakodi B, Tölken LA, Hoßmann J, Hoff KJ, Hyldegaard O, Nekludov M, Svensson M, Arnell P, Skrede S, Norrby-Teglund A, Siemens N. Neutrophil-derived reactive agents induce a transient SpeB negative phenotype in Streptococcus pyogenes. J Biomed Sci 2023; 30:52. [PMID: 37430325 DOI: 10.1186/s12929-023-00947-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 07/03/2023] [Indexed: 07/12/2023] Open
Abstract
BACKGROUND Streptococcus pyogenes (group A streptococci; GAS) is the main causative pathogen of monomicrobial necrotizing soft tissue infections (NSTIs). To resist immuno-clearance, GAS adapt their genetic information and/or phenotype to the surrounding environment. Hyper-virulent streptococcal pyrogenic exotoxin B (SpeB) negative variants caused by covRS mutations are enriched during infection. A key driving force for this process is the bacterial Sda1 DNase. METHODS Bacterial infiltration, immune cell influx, tissue necrosis and inflammation in patient´s biopsies were determined using immunohistochemistry. SpeB secretion and activity by GAS post infections or challenges with reactive agents were determined via Western blot or casein agar and proteolytic activity assays, respectively. Proteome of GAS single colonies and neutrophil secretome were profiled, using mass spectrometry. RESULTS Here, we identify another strategy resulting in SpeB-negative variants, namely reversible abrogation of SpeB secretion triggered by neutrophil effector molecules. Analysis of NSTI patient tissue biopsies revealed that tissue inflammation, neutrophil influx, and degranulation positively correlate with increasing frequency of SpeB-negative GAS clones. Using single colony proteomics, we show that GAS isolated directly from tissue express but do not secrete SpeB. Once the tissue pressure is lifted, GAS regain SpeB secreting function. Neutrophils were identified as the main immune cells responsible for the observed phenotype. Subsequent analyses identified hydrogen peroxide and hypochlorous acid as reactive agents driving this phenotypic GAS adaptation to the tissue environment. SpeB-negative GAS show improved survival within neutrophils and induce increased degranulation. CONCLUSIONS Our findings provide new information about GAS fitness and heterogeneity in the soft tissue milieu and provide new potential targets for therapeutic intervention in NSTIs.
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Affiliation(s)
- Patience Shumba
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany
| | - Thomas Sura
- Department of Microbial Proteomics, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Kirsten Moll
- Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | - Bhavya Chakrakodi
- Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | - Lea A Tölken
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany
| | - Jörn Hoßmann
- Helmholtz Center for Infection Research, Brunswick, Germany
| | - Katharina J Hoff
- Institute of Mathematics and Computer Science, University of Greifswald, Greifswald, Germany
| | - Ole Hyldegaard
- Department of Anaesthesia, Head and Orthopedic Center, University Hospital Copenhagen, Rigshospitalet, Copenhagen, Denmark
- Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Michael Nekludov
- Department of Anaesthesia, Surgical Services and Intensive Care, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden
| | - Mattias Svensson
- Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | - Per Arnell
- Department of Anaesthesiology and Intensive Care Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Steinar Skrede
- Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Anna Norrby-Teglund
- Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | - Nikolai Siemens
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany.
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Hachani A, Giulieri SG, Guérillot R, Walsh CJ, Herisse M, Soe YM, Baines SL, Thomas DR, Cheung SD, Hayes AS, Cho E, Newton HJ, Pidot S, Massey RC, Howden BP, Stinear TP. A high-throughput cytotoxicity screening platform reveals agr-independent mutations in bacteraemia-associated Staphylococcus aureus that promote intracellular persistence. eLife 2023; 12:84778. [PMID: 37289634 DOI: 10.7554/elife.84778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 05/23/2023] [Indexed: 06/10/2023] Open
Abstract
Staphylococcus aureus infections are associated with high mortality rates. Often considered an extracellular pathogen, S. aureus can persist and replicate within host cells, evading immune responses, and causing host cell death. Classical methods for assessing S. aureus cytotoxicity are limited by testing culture supernatants and endpoint measurements that do not capture the phenotypic diversity of intracellular bacteria. Using a well-established epithelial cell line model, we have developed a platform called InToxSa (intracellular toxicity of S. aureus) to quantify intracellular cytotoxic S. aureus phenotypes. Studying a panel of 387 S. aureus bacteraemia isolates, and combined with comparative, statistical, and functional genomics, our platform identified mutations in S. aureus clinical isolates that reduced bacterial cytotoxicity and promoted intracellular persistence. In addition to numerous convergent mutations in the Agr quorum sensing system, our approach detected mutations in other loci that also impacted cytotoxicity and intracellular persistence. We discovered that clinical mutations in ausA, encoding the aureusimine non-ribosomal peptide synthetase, reduced S. aureus cytotoxicity, and increased intracellular persistence. InToxSa is a versatile, high-throughput cell-based phenomics platform and we showcase its utility by identifying clinically relevant S. aureus pathoadaptive mutations that promote intracellular residency.
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Affiliation(s)
- Abderrahman Hachani
- Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Stefano G Giulieri
- Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Romain Guérillot
- Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Calum J Walsh
- Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Marion Herisse
- Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Ye Mon Soe
- Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Sarah L Baines
- Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
| | - David R Thomas
- Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
- Infection and Immunity Program, Department of Microbiology and Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Shane Doris Cheung
- Biological Optical Microscopy Platform, University of Melbourne, Melbourne, Australia
| | - Ashleigh S Hayes
- Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Ellie Cho
- Biological Optical Microscopy Platform, University of Melbourne, Melbourne, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
- Infection and Immunity Program, Department of Microbiology and Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Sacha Pidot
- Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Ruth C Massey
- School of Microbiology, University College Cork, Cork, Ireland
- School of Medicine, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Benjamin P Howden
- Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
- Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, Doherty Institute, University of Melbourne, Melbourne, Australia
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7
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Youssef CRB, Kadry AA, Mohammed El-Ganiny A. The alarming coincidence of toxin genes with staphylococcal cassette Chromosome mec (SCCmec) in clinical MRSA isolates. Saudi J Biol Sci 2022. [DOI: 10.1016/j.sjbs.2022.02.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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8
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Cuypers F, Schäfer A, Skorka SB, Surabhi S, Tölken LA, Paulikat AD, Kohler TP, Otto SA, Mettenleiter TC, Hammerschmidt S, Blohm U, Siemens N. Innate immune responses at the asymptomatic stage of influenza A viral infections of Streptococcus pneumoniae colonized and non-colonized mice. Sci Rep 2021; 11:20609. [PMID: 34663857 PMCID: PMC8523748 DOI: 10.1038/s41598-021-00211-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/07/2021] [Indexed: 11/09/2022] Open
Abstract
Seasonal Influenza A virus (IAV) infections can promote dissemination of upper respiratory tract commensals such as Streptococcus pneumoniae to the lower respiratory tract resulting in severe life-threatening pneumonia. Here, we aimed to compare innate immune responses in the lungs of healthy colonized and non-colonized mice after IAV challenge at the initial asymptomatic stage of infection. Responses during a severe bacterial pneumonia were profiled for comparison. Cytokine and innate immune cell imprints of the lungs were analyzed. Irrespective of the colonization status, mild H1N1 IAV infection was characterized by a bi-phasic disease progression resulting in full recovery of the animals. Already at the asymptomatic stage of viral infection, the pro-inflammatory cytokine response was as high as in pneumococcal pneumonia. Flow cytometry analyses revealed an early influx of inflammatory monocytes into the lungs. Neutrophil influx was mostly limited to bacterial infections. The majority of cells, except monocytes, displayed an activated phenotype characterized by elevated CCR2 and MHCII expression. In conclusion, we show that IAV challenge of colonized healthy mice does not automatically result in severe co-infection. However, a general local inflammatory response was noted at the asymptomatic stage of infection irrespective of the infection type.
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Affiliation(s)
- Fabian Cuypers
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany
| | - Alexander Schäfer
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald - Island of Riems, Germany
| | - Sebastian B Skorka
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany
| | - Surabhi Surabhi
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany
| | - Lea A Tölken
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany
| | - Antje D Paulikat
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany
| | - Thomas P Kohler
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany
| | - Saskia A Otto
- Institute for Marine Ecosystem and Fisheries Science (IMF), Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, Germany
| | - Thomas C Mettenleiter
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald - Island of Riems, Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany.
| | - Ulrike Blohm
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald - Island of Riems, Germany
| | - Nikolai Siemens
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany.
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Streptococcus pyogenes ("Group A Streptococcus"), a Highly Adapted Human Pathogen-Potential Implications of Its Virulence Regulation for Epidemiology and Disease Management. Pathogens 2021; 10:pathogens10060776. [PMID: 34205500 PMCID: PMC8234341 DOI: 10.3390/pathogens10060776] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/02/2021] [Accepted: 06/17/2021] [Indexed: 11/16/2022] Open
Abstract
Streptococcus pyogenes (group A streptococci; GAS) is an exclusively human pathogen. It causes a variety of suppurative and non-suppurative diseases in people of all ages worldwide. Not all can be successfully treated with antibiotics. A licensed vaccine, in spite of its global importance, is not yet available. GAS express an arsenal of virulence factors responsible for pathological immune reactions. The transcription of all these virulence factors is under the control of three types of virulence-related regulators: (i) two-component systems (TCS), (ii) stand-alone regulators, and (iii) non-coding RNAs. This review summarizes major TCS and stand-alone transcriptional regulatory systems, which are directly associated with virulence control. It is suggested that this treasure of knowledge on the genetics of virulence regulation should be better harnessed for new therapies and prevention methods for GAS infections, thereby changing its global epidemiology for the better.
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10
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Ridyard KE, Overhage J. The Potential of Human Peptide LL-37 as an Antimicrobial and Anti-Biofilm Agent. Antibiotics (Basel) 2021; 10:antibiotics10060650. [PMID: 34072318 PMCID: PMC8227053 DOI: 10.3390/antibiotics10060650] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 02/06/2023] Open
Abstract
The rise in antimicrobial resistant bacteria threatens the current methods utilized to treat bacterial infections. The development of novel therapeutic agents is crucial in avoiding a post-antibiotic era and the associated deaths from antibiotic resistant pathogens. The human antimicrobial peptide LL-37 has been considered as a potential alternative to conventional antibiotics as it displays broad spectrum antibacterial and anti-biofilm activities as well as immunomodulatory functions. While LL-37 has shown promising results, it has yet to receive regulatory approval as a peptide antibiotic. Despite the strong antimicrobial properties, LL-37 has several limitations including high cost, lower activity in physiological environments, susceptibility to proteolytic degradation, and high toxicity to human cells. This review will discuss the challenges associated with making LL-37 into a viable antibiotic treatment option, with a focus on antimicrobial resistance and cross-resistance as well as adaptive responses to sub-inhibitory concentrations of the peptide. The possible methods to overcome these challenges, including immobilization techniques, LL-37 delivery systems, the development of LL-37 derivatives, and synergistic combinations will also be considered. Herein, we describe how combination therapy and structural modifications to the sequence, helicity, hydrophobicity, charge, and configuration of LL-37 could optimize the antimicrobial and anti-biofilm activities of LL-37 for future clinical use.
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11
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Yi L, Dong X, Grenier D, Wang K, Wang Y. Research progress of bacterial quorum sensing receptors: Classification, structure, function and characteristics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 763:143031. [PMID: 33129525 DOI: 10.1016/j.scitotenv.2020.143031] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 09/16/2020] [Accepted: 10/10/2020] [Indexed: 06/11/2023]
Abstract
The microbial community is an important part of the natural ecosystem, and the quorum sensing system is a momentous communication tool for the microbial community to connect to the surrounding environment. Quorum sensing is a process of cell-cell communication that relies on the production, release, and detection of extracellular signaling molecules, which are called autoinducers. Quorum sensing systems in bacteria consist of two main components: a receptor protein and an autoinducer. The binding of autoinducer to its receptor activates the target gene, which then performs the corresponding function in bacteria. In a natural environment, different bacterial species possess quorum sensing receptors that are structurally and functionally different. So far, many bacterial quorum sensing receptors have been identified and the structure and function of some receptors have been characterized. There are many reviews about quorum sensing and quorum sensing receptors, but there are few reviews that describe various types of quorum sensing in different environments with receptors as the core. Therefore, we summarize the well-defined quorum sensing receptors involved in intra-species and inter-species cell-cell communication, and describe the structure, function, and characteristics of typical receptors for different types of quorum sensing. A systematic understanding of quorum sensing receptors will help researchers to further explore the signaling mechanism and regulation mechanism of quorum sensing system, provide help to clarify the role and function of quorum sensing in natural ecosystems, then provide theoretical basis for the discovery or synthesis of new targeted drugs that block quorum sensing.
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Affiliation(s)
- Li Yi
- College of Life Science, Luoyang Normal University, Luoyang, China; Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Xiao Dong
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Daniel Grenier
- Groupe de Recherche en Écologie Buccale (GREB), Faculté de Médecine Dentaire, Université Laval, Quebec City, QC, Canada
| | - Kaicheng Wang
- China Animal Health and Epidemiology Center, Qingdao, China
| | - Yang Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China.
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12
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The INFECT-Project: An International and Multidisciplinary Project on Necrotizing Soft Tissue Infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021. [PMID: 33079359 DOI: 10.1007/978-3-030-57616-5_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
This book describes clinical and microbiologic aspects, pathogenesis, and diagnostics, related to the severe and rapidly spreading necrotizing soft tissue infections. The work has its foundation in a recently completed European Union funded FP7-project called INFECT, which during the period 2013-2018 focused on utilizing a systems medicine approach to increase our understanding of these heterogenous and complex life-threatening infections. In this chapter, the aim and scope as well as key achievements of the INFECT-project are described.
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13
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Siemens N, Snäll J, Svensson M, Norrby-Teglund A. Pathogenic Mechanisms of Streptococcal Necrotizing Soft Tissue Infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1294:127-150. [PMID: 33079367 DOI: 10.1007/978-3-030-57616-5_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Necrotizing skin and soft tissue infections (NSTIs) are severe life-threatening and rapidly progressing infections. Beta-hemolytic streptococci, particularly S. pyogenes (group A streptococci (GAS)) but also S. dysgalactiae subsp. equisimilis (SDSE, most group G and C streptococcus), are the main causative agents of monomicrobial NSTIs and certain types, such as emm1 and emm3, are over-represented in NSTI cases. An arsenal of bacterial virulence factors contribute to disease pathogenesis, which is a complex and multifactorial process. In this chapter, we summarize data that have provided mechanistic and immuno-pathologic insight into host-pathogens interactions that contribute to tissue pathology in streptococcal NSTIs. The role of streptococcal surface associated and secreted factors contributing to the hyper-inflammatory state and immune evasion, bacterial load in the tissue and persistence strategies, including intracellular survival and biofilm formation, as well as strategies to mimic NSTIs in vitro are discussed.
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Affiliation(s)
- Nikolai Siemens
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany.
| | - Johanna Snäll
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Mattias Svensson
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Anna Norrby-Teglund
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Huddinge, Sweden
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Huang Q, Xie Y, Yang Z, Cheng D, He L, Wang H, Liu Q, Li M. The cytoplasmic loops of AgrC contribute to the quorum-sensing activity of Staphylococcus aureus. J Microbiol 2020; 59:92-100. [PMID: 33201435 DOI: 10.1007/s12275-021-0274-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 09/22/2020] [Accepted: 09/25/2020] [Indexed: 11/29/2022]
Abstract
In Staphylococcus aureus, the accessory gene regulator (agr) quorum-sensing system is thought to play an important role in biofilm formation. The histidine kinase AgrC is one of the agr system components and activated by the self-generated auto-inducing peptide (AIP), which is released continuously into the extracellular environment during bacterial growth. The extracellular loops (Extra-loops) of AgrC are crucial for AIP binding. Here, we reported that the cytoplasmic loops (Cyto-loops) of AgrC are also involved in Agr activity. We identified S. aureus ST398 clinical isolates containing a naturally occurring single amino acid substitution (lysine to isoleucine) at position 73 of an AgrC Cyto-loop that exhibited significantly stronger biofilm formation and decreased Agr activity compared to the wild-type strain. A constructed strain containing the K73I point mutation in AgrC Cyto-loop continued to show a growth dependent induction of the agr system, although the growth dependent induction was delayed by about 6 h compared to the wild-type. In addition, a series of strains containing deletion mutants of the AgrC Cyto- and Extra-loops were constructed and revealed that the removal of the two Cyto-loops and Extra-loops 2 and 3 totally abolished the Agr activity and the growth-dependence on the agr system induction. Remarkably, the Extra-loop 1 deletion did not affect the Agr activity. In conclusion, the AgrC Cyto-loops play a crucial role in the S. aureus quorum-sensing activity.
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Affiliation(s)
- Qian Huang
- Department of Laboratory Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, P. R. China
| | - Yihui Xie
- Department of Laboratory Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, P. R. China
| | - Ziyu Yang
- Department of Laboratory Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, P. R. China
| | - Danhong Cheng
- Department of Laboratory Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, P. R. China
| | - Lei He
- Department of Laboratory Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, P. R. China
| | - Hua Wang
- Department of Laboratory Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, P. R. China
| | - Qian Liu
- Department of Laboratory Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, P. R. China.
| | - Min Li
- Department of Laboratory Medicine, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, P. R. China.
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16HBE Cell Lipid Mediator Responses to Mono and Co-Infections with Respiratory Pathogens. Metabolites 2020; 10:metabo10030113. [PMID: 32197522 PMCID: PMC7142531 DOI: 10.3390/metabo10030113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 03/12/2020] [Accepted: 03/13/2020] [Indexed: 12/15/2022] Open
Abstract
Respiratory tract infections are a global health problem. The main causative agents of these infections are influenza A virus (IAV), Staphylococcus aureus (S. aureus), and Streptococcus pneumoniae (S. pneumoniae). Major research focuses on genetics and immune responses in these infections. Eicosanoids and other oxylipins are host-derived lipid mediators that play an important role in the activation and resolution of inflammation. In this study, we assess, for the first time, the different intracellular profiles of these bioactive lipid mediators during S. aureus LUG2012, S. pneumoniae TIGR4, IAV, and corresponding viral and bacterial co-infections of 16HBE cells. We observed a multitude of altered lipid mediators. Changes in the amount of 5-hydroxyeicosatetraenoic acid (5-HETE) were prominent for all bacterial infections. The infection with S. pneumoniae showed the strongest impact on bioactive lipid production and led to alterations in the amount of PPARγ ligands and precursors of pro-resolving lipid mediators.
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16
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Siemens N, Oehmcke-Hecht S, Hoßmann J, Skorka SB, Nijhuis RHT, Ruppen C, Skrede S, Rohde M, Schultz D, Lalk M, Itzek A, Pieper DH, van den Bout CJ, Claas ECJ, Kuijper EJ, Mauritz R, Sendi P, Wunderink HF, Norrby-Teglund A. Prothrombotic and Proinflammatory Activities of the β-Hemolytic Group B Streptococcal Pigment. J Innate Immun 2019; 12:291-303. [PMID: 31743913 DOI: 10.1159/000504002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 10/06/2019] [Indexed: 12/29/2022] Open
Abstract
A prominent feature of severe streptococcal infections is the profound inflammatory response that contributes to systemic toxicity. In sepsis the dysregulated host response involves both immunological and nonimmunological pathways. Here, we report a fatal case of an immunocompetent healthy female presenting with toxic shock and purpura fulminans caused by group B streptococcus (GBS; serotype III, CC19). The strain (LUMC16) was pigmented and hyperhemolytic. Stimulation of human primary cells with hyperhemolytic LUMC16 and STSS/NF-HH strains and pigment toxin resulted in a release of proinflammatory mediators, including tumor necrosis factor, interleukin (IL)-1β, and IL-6. In addition, LUMC16 induced blood clotting and showed factor XII activity on its surface, which was linked to the presence of the pigment. The expression of pigment was not linked to a mutation within the CovR/S region. In conclusion, our study shows that the hemolytic lipid toxin contributes to the ability of GBS to cause systemic hyperinflammation and interferes with the coagulation system.
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Affiliation(s)
- Nikolai Siemens
- Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden, .,Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany,
| | - Sonja Oehmcke-Hecht
- Institute of Medical Microbiology, Virology, and Hygiene, University Medicine Rostock, Rostock, Germany
| | - Jörn Hoßmann
- Microbial Interactions and Processes, Helmholtz Centre for Infection Research - HZI, Braunschweig, Germany
| | - Sebastian B Skorka
- Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany
| | - Roel H T Nijhuis
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Medical Microbiology and Medical Immunology, Meander Medical Center, Amersfoort, The Netherlands
| | - Corinne Ruppen
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Steinar Skrede
- Department of Medicine, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research - HZI, Braunschweig, Germany
| | - Daniel Schultz
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Michael Lalk
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Andreas Itzek
- Microbial Interactions and Processes, Helmholtz Centre for Infection Research - HZI, Braunschweig, Germany
| | - Dietmar H Pieper
- Microbial Interactions and Processes, Helmholtz Centre for Infection Research - HZI, Braunschweig, Germany
| | | | - Eric C J Claas
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Ed J Kuijper
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Robert Mauritz
- Department of Intensive Care Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Parham Sendi
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Herman F Wunderink
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Anna Norrby-Teglund
- Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
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Abstract
Staphylococci, and in particular Staphylococcus aureus, cause an extensive variety of infections in a range of hosts. The comprehensive analysis of staphylococcal genomes reveals mechanisms controlling the organism's biology, pathobiology, and dissemination. Whole-genome sequencing technologies led to a quantum leap in our understanding of bacterial genomes. The recent cost reduction of sequencing has resulted in unprecedented volumes of genomic information about S. aureus, one of the most sequenced bacterial species. Collecting, comparing, and interpreting big data is challenging, but fascinating insights have emerged. For example, it is becoming clearer which selective pressures staphylococci face in their habitats and which mechanisms allow this pathogen to adapt, survive, and spread. A key theme is the constant evolution of staphylococci as they alter their genome, exchange DNA, and adapt to new environments, leading to the emergence of increasingly successful, antibiotic-resistant, immune-evading, and host-adapted colonizers and pathogens. This article introduces the structure of staphylococcal genomes, details how genomes vary between strains, outlines the mechanisms of genetic variation, and describes the features of successful clones.
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Affiliation(s)
- Jodi A Lindsay
- St. George's, University of London, Institute of Infection and Immunity, London, United Kingdom
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18
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Timing Is Everything: Impact of Naturally Occurring Staphylococcus aureus AgrC Cytoplasmic Domain Adaptive Mutations on Autoinduction. J Bacteriol 2019; 201:JB.00409-19. [PMID: 31358609 PMCID: PMC6755735 DOI: 10.1128/jb.00409-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 07/22/2019] [Indexed: 01/19/2023] Open
Abstract
Virulence factor expression in Staphylococcus aureus is regulated via autoinducing peptide (AIP)-dependent activation of the sensor kinase AgrC, which forms an integral part of the agr quorum sensing system. In response to bound AIP, the cytoplasmic domain of AgrC (AgrC-cyt) undergoes conformational changes resulting in dimerization, autophosphorylation, and phosphotransfer to the response regulator AgrA. Naturally occurring mutations in AgrC-cyt are consistent with repositioning of key functional domains, impairing dimerization and restricting access to the ATP-binding pocket. Strains harboring specific AgrC-cyt mutations exhibit reduced AIP autoinduction efficiency and a timing-dependent attenuation of cytotoxicity which may confer a survival advantage during established infection by promoting colonization while restricting unnecessary overproduction of exotoxins. Mutations in the polymorphic Staphylococcus aureusagr locus responsible for quorum sensing (QS)-dependent virulence gene regulation occur frequently during host adaptation. In two genomically closely related S. aureus clinical isolates exhibiting marked differences in Panton-Valentine leukocidin production, a mutation conferring an N267I substitution was identified in the cytoplasmic domain of the QS sensor kinase, AgrC. This natural mutation delayed the onset and accumulation of autoinducing peptide (AIP) and showed reduced responsiveness to exogenous AIPs. Other S. aureus strains harboring naturally occurring AgrC cytoplasmic domain mutations were identified, including T247I, I311T, A343T, L245S, and F264C. These mutations were associated with reduced cytotoxicity, delayed/reduced AIP production, and impaired sensitivity to exogenous AIP. Molecular dynamics simulations were used to model the AgrC cytoplasmic domain conformational changes arising. Although mutations were localized in different parts of the C-terminal domain, their impact on molecular structure was manifested by twisting of the leading helical hairpin α1-α2, accompanied by repositioning of the H-box and G-box, along with closure of the flexible loop connecting the two and occlusion of the ATP-binding site. Such conformational rearrangements of key functional subdomains in these mutants highlight the cooperative response of molecular structure involving dimerization and ATP binding and phosphorylation, as well as the binding site for the downstream response element AgrA. These appear to increase the threshold for agr activation via AIP-dependent autoinduction, thus reducing virulence and maintaining S. aureus in an agr-downregulated “colonization” mode. IMPORTANCE Virulence factor expression in Staphylococcus aureus is regulated via autoinducing peptide (AIP)-dependent activation of the sensor kinase AgrC, which forms an integral part of the agr quorum sensing system. In response to bound AIP, the cytoplasmic domain of AgrC (AgrC-cyt) undergoes conformational changes resulting in dimerization, autophosphorylation, and phosphotransfer to the response regulator AgrA. Naturally occurring mutations in AgrC-cyt are consistent with repositioning of key functional domains, impairing dimerization and restricting access to the ATP-binding pocket. Strains harboring specific AgrC-cyt mutations exhibit reduced AIP autoinduction efficiency and a timing-dependent attenuation of cytotoxicity which may confer a survival advantage during established infection by promoting colonization while restricting unnecessary overproduction of exotoxins.
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19
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The Role of Streptococcal and Staphylococcal Exotoxins and Proteases in Human Necrotizing Soft Tissue Infections. Toxins (Basel) 2019; 11:toxins11060332. [PMID: 31212697 PMCID: PMC6628391 DOI: 10.3390/toxins11060332] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 06/04/2019] [Accepted: 06/10/2019] [Indexed: 12/31/2022] Open
Abstract
Necrotizing soft tissue infections (NSTIs) are critical clinical conditions characterized by extensive necrosis of any layer of the soft tissue and systemic toxicity. Group A streptococci (GAS) and Staphylococcus aureus are two major pathogens associated with monomicrobial NSTIs. In the tissue environment, both Gram-positive bacteria secrete a variety of molecules, including pore-forming exotoxins, superantigens, and proteases with cytolytic and immunomodulatory functions. The present review summarizes the current knowledge about streptococcal and staphylococcal toxins in NSTIs with a special focus on their contribution to disease progression, tissue pathology, and immune evasion strategies.
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20
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Xie Q, Zhao A, Jeffrey PD, Kim MK, Bassler BL, Stone HA, Novick RP, Muir TW. Identification of a Molecular Latch that Regulates Staphylococcal Virulence. Cell Chem Biol 2019; 26:548-558.e4. [PMID: 30773482 DOI: 10.1016/j.chembiol.2019.01.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 11/27/2018] [Accepted: 01/10/2019] [Indexed: 01/04/2023]
Abstract
Virulence induction in the Staphylococcus aureus is under the control of a quorum sensing (QS) circuit encoded by the accessory gene regulator (agr) locus. Allelic variation within agr produces four QS specificity groups, each producing a unique secreted autoinducer peptide (AIP) and receptor histidine kinase (RHK), AgrC. Cognate AIP-AgrC interactions activate virulence through a two-component signaling cascade, whereas non-cognate pairs are generally inhibitory. Here we pinpoint a key hydrogen-bonding interaction within AgrC that acts as a switch to convert helical motions propagating from the receptor sensor domain into changes in inter-domain association within the kinase module. AgrC mutants lacking this interaction are constitutively active in vitro and in vivo, the latter leading to a pronounced attenuation of S. aureus biofilm formation. Thus, our work sheds light on the regulation of this biomedically important RHK.
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Affiliation(s)
- Qian Xie
- Department of Chemistry, Princeton University, Frick Chemistry Laboratory, Washington Road, Princeton, NJ 08544-0015, USA
| | - Aishan Zhao
- Department of Chemistry, Princeton University, Frick Chemistry Laboratory, Washington Road, Princeton, NJ 08544-0015, USA
| | - Philip D Jeffrey
- Department of Molecular Biology, Princeton University, Schultz Laboratory, Washington Road, Princeton, NJ 08544, USA
| | - Minyoung Kevin Kim
- Department of Chemistry, Princeton University, Frick Chemistry Laboratory, Washington Road, Princeton, NJ 08544-0015, USA
| | - Bonnie L Bassler
- Department of Molecular Biology, Princeton University, Schultz Laboratory, Washington Road, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Engineering Quadrangle, Olden Street, Princeton, NJ 08544, USA
| | - Richard P Novick
- Skirball Institute, Department of Microbiology, NYU Medical Center, 540-562 First Avenue, New York, NY 10016, USA
| | - Tom W Muir
- Department of Chemistry, Princeton University, Frick Chemistry Laboratory, Washington Road, Princeton, NJ 08544-0015, USA.
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21
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Nygaard TK, Borgogna TR, Sward EW, Guerra FE, Dankoff JG, Collins MM, Pallister KB, Chen L, Kreiswirth BN, Voyich JM. Aspartic Acid Residue 51 of SaeR Is Essential for Staphylococcus aureus Virulence. Front Microbiol 2018; 9:3085. [PMID: 30619166 PMCID: PMC6302044 DOI: 10.3389/fmicb.2018.03085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 11/29/2018] [Indexed: 11/13/2022] Open
Abstract
Staphylococcus aureus is a common Gram-positive bacteria that is a major cause of human morbidity and mortality. The SaeR/S two-component sensory system of S. aureus is important for virulence gene transcription and pathogenesis. However, the influence of SaeR phosphorylation on virulence gene transcription is not clear. To determine the importance of potential SaeR phosphorylation sites for S. aureus virulence, we generated genomic alanine substitutions at conserved aspartic acid residues in the receiver domain of the SaeR response regulator in clinically significant S. aureus pulsed-field gel electrophoresis (PFGE) type USA300. Transcriptional analysis demonstrated a dramatic reduction in the transcript abundance of various toxins, adhesins, and immunomodulatory proteins for SaeR with an aspartic acid to alanine substitution at residue 51. These findings corresponded to a significant decrease in cytotoxicity against human erythrocytes and polymorphonuclear leukocytes, the ability to block human myeloperoxidase activity, and pathogenesis during murine soft-tissue infection. Analysis of SaeR sequences from over 8,000 draft S. aureus genomes revealed that aspartic acid residue 51 is 100% conserved. Collectively, these results demonstrate that aspartic acid residue 51 of SaeR is essential for S. aureus virulence and underscore a conserved target for novel antimicrobial strategies that treat infection caused by this pathogen.
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Affiliation(s)
- Tyler K Nygaard
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
| | - Timothy R Borgogna
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
| | - Eli W Sward
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
| | - Fermin E Guerra
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
| | - Jennifer G Dankoff
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
| | - Madison M Collins
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
| | - Kyler B Pallister
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
| | - Liang Chen
- Public Health Research Institute Tuberculosis Center, New Jersey Medical School, Rutgers University, Newark, NJ, United States
| | - Barry N Kreiswirth
- Public Health Research Institute Tuberculosis Center, New Jersey Medical School, Rutgers University, Newark, NJ, United States
| | - Jovanka M Voyich
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
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22
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Group A Streptococcal DNase Sda1 Impairs Plasmacytoid Dendritic Cells' Type 1 Interferon Response. J Invest Dermatol 2018; 139:1284-1293. [PMID: 30543898 DOI: 10.1016/j.jid.2018.11.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 01/19/2023]
Abstract
Group A Streptococcus causes severe invasive infections, including necrotizing fasciitis. The expression of an array of virulence factors targeting specific host immune functions impedes successful bacterial clearance. The virulence factor streptococcal DNase Sda1 was previously shown to interfere with the entrapment of bacteria through neutrophil extracellular traps and TLR9 signaling. In this study, we showed that plasmacytoid dendritic cells are recruited to the infected tissue during group A streptococcal necrotizing fasciitis. We found that the streptococcal DNase Sda1 impairs plasmacytoid dendritic cell recruitment by reducing IFN-1 levels at the site of infection. We found that streptococcal DNase Sda1 interferes with stabilization of the DNA by the host molecule HMGB1 protein, which may account for decreased IFN-1 levels at the site of infection.
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23
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Schleimer N, Kaspar U, Drescher M, Seggewiß J, von Eiff C, Proctor RA, Peters G, Kriegeskorte A, Becker K. The Energy-Coupling Factor Transporter Module EcfAA'T, a Novel Candidate for the Genetic Basis of Fatty Acid-Auxotrophic Small-Colony Variants of Staphylococcus aureus. Front Microbiol 2018; 9:1863. [PMID: 30154773 PMCID: PMC6102330 DOI: 10.3389/fmicb.2018.01863] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/25/2018] [Indexed: 11/29/2022] Open
Abstract
Staphylococcal small-colony variants (SCVs) are invasive and persistent due to their ability to thrive intracellularly and to evade the host immune response. Thus, the course of infections due to this phenotype is often chronic, relapsing, and therapy-refractory. In order to improve treatment of patients suffering from SCV-associated infections, it is of major interest to understand triggers for the development of this phenotype, in particular for strains naturally occurring in clinical settings. Within this study, we comprehensively characterized two different Staphylococcus aureus triplets each consisting of isogenic strains comprising (i) clinically derived SCV phenotypes with auxotrophy for unsaturated fatty acids, (ii) the corresponding wild-types (WTs), and (iii) spontaneous in vitro revertants displaying the normal phenotype (REVs). Comparison of whole genomes revealed that clinical SCV isolates were closely related to their corresponding WTs and REVs showing only seven to eight alterations per genome triplet. However, both SCVs carried a mutation within the energy-coupling factor (ECF) transporter-encoding ecf module (EcfAA’T) resulting in truncated genes. In both cases, these mutations were shown to be naturally restored in the respective REVs. Since ECF transporters are supposed to be essential for optimal bacterial growth, their dysfunction might constitute another mechanism for the formation of naturally occurring SCVs. Another three triplets analyzed revealed neither mutations in the EcfAA’T nor in other FASII-related genes underlining the high diversity of mechanisms leading to the fatty acid-dependent phenotype. This is the first report on the ECF transporter as genetic basis of fatty acid–auxotrophic staphylococcal SCVs.
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Affiliation(s)
- Nina Schleimer
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Ursula Kaspar
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Mike Drescher
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Jochen Seggewiß
- Institute of Human Genetics, University Hospital Münster, Münster, Germany
| | - Christof von Eiff
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Richard A Proctor
- Departments of Medical Microbiology/Immunology and Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Georg Peters
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - André Kriegeskorte
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Karsten Becker
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
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24
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Tan L, Li SR, Jiang B, Hu XM, Li S. Therapeutic Targeting of the Staphylococcus aureus Accessory Gene Regulator ( agr) System. Front Microbiol 2018; 9:55. [PMID: 29422887 PMCID: PMC5789755 DOI: 10.3389/fmicb.2018.00055] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/10/2018] [Indexed: 11/19/2022] Open
Abstract
Staphylococcus aureus can cause numerous different diseases, which has been attributed to its large repertoire of virulence factors, many of which are under the control of the accessory gene regulator (agr) quorum sensing system. Under conditions of high cell density, agr increases the production of many virulence factors, decreases expression of several colonization factors, and is intimately associated with the pathogenesis and biofilm formation of S. aureus. This review summarizes our current understanding of the molecular mechanisms underlying agr quorum sensing and the regulation of agr expression. The discussion also examines subgroups of agr and their association with different diseases, and concludes with an analysis of strategies for designing drugs and vaccines that target agr to combat S. aureus infections.
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Affiliation(s)
- Li Tan
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Si Rui Li
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Bei Jiang
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Xiao Mei Hu
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Shu Li
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
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25
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Siemens N, Oehmcke-Hecht S, Mettenleiter TC, Kreikemeyer B, Valentin-Weigand P, Hammerschmidt S. Port d'Entrée for Respiratory Infections - Does the Influenza A Virus Pave the Way for Bacteria? Front Microbiol 2017; 8:2602. [PMID: 29312268 PMCID: PMC5742597 DOI: 10.3389/fmicb.2017.02602] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/13/2017] [Indexed: 12/12/2022] Open
Abstract
Bacterial and viral co-infections of the respiratory tract are life-threatening and present a global burden to the global community. Staphylococcus aureus, Streptococcus pneumoniae, and Streptococcus pyogenes are frequent colonizers of the upper respiratory tract. Imbalances through acquisition of seasonal viruses, e.g., Influenza A virus, can lead to bacterial dissemination to the lower respiratory tract, which in turn can result in severe pneumonia. In this review, we summarize the current knowledge about bacterial and viral co-infections of the respiratory tract and focus on potential experimental models suitable for mimicking this disease. Transmission of IAV and pneumonia is mainly modeled by mouse infection. Few studies utilizing ferrets, rats, guinea pigs, rabbits, and non-human primates are also available. The knowledge gained from these studies led to important discoveries and advances in understanding these infectious diseases. Nevertheless, mouse and other infection models have limitations, especially in translation of the discoveries to humans. Here, we suggest the use of human engineered lung tissue, human ex vivo lung tissue, and porcine models to study respiratory co-infections, which might contribute to a greater translation of the results to humans and improve both, animal and human health.
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Affiliation(s)
- Nikolai Siemens
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
- Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Sonja Oehmcke-Hecht
- Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - Thomas C. Mettenleiter
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institute, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Bernd Kreikemeyer
- Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - Peter Valentin-Weigand
- Center for Infection Medicine, Institute for Microbiology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
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26
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Grinberg A, Biggs PJ, Zhang J, Ritchie S, Oneroa Z, O'Neill C, Karkaba A, Velathanthiri NS, Coombs GW. Genomic epidemiology of methicillin-susceptible Staphylococcus aureus across colonisation and skin and soft tissue infection. J Infect 2017; 75:326-335. [PMID: 28782565 DOI: 10.1016/j.jinf.2017.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 07/29/2017] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Staphylococcus aureus skin and soft tissue infection (Sa-SSTI) places a significant burden on healthcare systems. New Zealand has a high incidence of Sa-SSTI, and here most morbidity is caused by a polyclonal methicillin-susceptible (MSSA) bacterial population. However, MSSA also colonise asymptomatically the cornified epithelia of approximately 20% of the population, and their divide between commensalism and pathogenicity is poorly understood. We aimed to see whether MSSA are genetically differentiated across colonisation and SSTI; and given the close interactions between people and pets, whether strains isolated from pets differ from human strains. METHODS We compared the genomes of contemporaneous colonisation and clinical MSSA isolates obtained in New Zealand from humans and pets. RESULTS Core and accessory genome comparisons revealed a homogeneous bacterial population across colonisation, disease, humans, and pets. The rate of MSSA colonisation in dogs was comparatively low (5.4%). CONCLUSIONS In New Zealand, most Sa-SSTI morbidity is caused by a random sample of the colonising MSSA population, consistent with the opportunistic infection model rather than the paradigm distinguishing strains according to their pathogenicity. Thus, studies of the factors determining colonisation and immune-escape may be more beneficial than comparative virulence studies. Contact with house-hold pets may pose low zoonotic risk.
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Affiliation(s)
- Alex Grinberg
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand.
| | - Patrick J Biggs
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand
| | - Ji Zhang
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand
| | - Stephen Ritchie
- University of Auckland, Faculty of Medical and Health Sciences, Molecular Medicine and Pathology, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Zachary Oneroa
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand
| | - Charlotte O'Neill
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand
| | - Ali Karkaba
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand
| | - Niluka S Velathanthiri
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand
| | - Geoffrey W Coombs
- School of Veterinary and Life Sciences, Murdoch University, 90 South Street, Murdoch, WA, Australia
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