101
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Pant N, Eisen DP. Non-Antimicrobial Adjuvant Strategies to Tackle Biofilm-Related Staphylococcus aureus Prosthetic Joint Infections. Antibiotics (Basel) 2021; 10:antibiotics10091060. [PMID: 34572641 PMCID: PMC8465242 DOI: 10.3390/antibiotics10091060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 08/27/2021] [Accepted: 08/28/2021] [Indexed: 12/15/2022] Open
Abstract
Staphylococcus aureus frequently causes community- and hospital-acquired infections. S. aureus attachment followed by biofilm formation on tissues and medical devices plays a significant role in the establishment of chronic infections. Staphylococcal biofilms encase bacteria in a matrix and protect the cells from antimicrobials and the immune system, resulting in infections that are highly resistant to treatment. The biology of biofilms is complex and varies between organisms. In this review, we focus our discussion on S. aureus biofilms and describe the stages of their formation. We particularly emphasize genetic and biochemical processes that may be vulnerable to novel treatment approaches. Against this background, we discuss treatment strategies that have been successful in animal models of S. aureus biofilm-related infection and consider their possible use for the prevention and eradication of biofilm-related S. aureus prosthetic joint infection.
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102
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Nasser A, Dallal MMS, Jahanbakhshi S, Azimi T, Nikouei L. Staphylococcus aureus: biofilm formation and strategies against it. Curr Pharm Biotechnol 2021; 23:664-678. [PMID: 34238148 DOI: 10.2174/1389201022666210708171123] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 05/09/2021] [Accepted: 05/31/2021] [Indexed: 11/22/2022]
Abstract
The formation of Staphylococcus aureus biofilm causes significant infections in the human body. Biofilm forms through the aggregation of bacterial species and brings about many complications. It mediates drug resistance and persistence and facilitates the recurrence of infection at the end of antimicrobial therapy. Biofilm formation goes through a series of steps to complete, and any interference in these steps can disrupt its formation. Such interference may occur at any stage of biofilm production, including attachment, monolayer formation, and accumulation. Interfering agents can act as quorum sensing inhibitors and interfere in the functionality of quorum sensing receptors, attachment inhibitors and affect the cell hydrophobicity. Among these inhibiting strategies, attachment inhibitors could serve as the best agents against biofilm formation. If pathogens abort the attachment, the following stages of biofilm formation, e.g., accumulation and dispersion, will fail to materialize. Inhibition at this stage leads to suppression of virulence factors and invasion. One of the best-known inhibitors is a chelator that collects metal, Fe+, Zn+, and magnesium critical for biofilm formation. These influential factors in the binding and formation of biofilm are investigated, and the coping strategy is discussed. This review examines the stages of biofilm formation and determines what factors interfere in the continuity of these steps. Finally, the inhibition strategies are investigated, reviewed, and discussed. Keywords: Biofilm, Staphylococcus, Biofilm inhibitor, Dispersion, Antibiofilm agent, EPS, PIA.
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Affiliation(s)
- Ahmad Nasser
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Shiva Jahanbakhshi
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Taher Azimi
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Leila Nikouei
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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103
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Interference in Staphylococcus Aureus Biofilm and Virulence Factors Production by Human Probiotic Bacteria with Antimutagenic Activity. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2021. [DOI: 10.1007/s13369-021-05934-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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104
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Mahdally NH, George RF, Kashef MT, Al-Ghobashy M, Murad FE, Attia AS. Staquorsin: A Novel Staphylococcus aureus Agr-Mediated Quorum Sensing Inhibitor Impairing Virulence in vivo Without Notable Resistance Development. Front Microbiol 2021; 12:700494. [PMID: 34290689 PMCID: PMC8287904 DOI: 10.3389/fmicb.2021.700494] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 06/11/2021] [Indexed: 12/11/2022] Open
Abstract
The emergence of microbial resistance to the available antibiotics is a major public health concern, especially with the limited rate of developing new antibiotics. The utilization of anti-virulence agents is a non-conventional approach that can be used to combat microbial infection. In Staphylococcus aureus, many virulence factors are regulated by the Agr-mediated quorum sensing (QS). We developed a chemical compound that acts a potential Agr-inhibitor without reducing bacterial viability. The compound was designated staquorsin for Staphylococcus aureus QS inhibitor. In silico analyses confirmed the binding of staquorsin to the AgrA active site with an absolute binding score comparable to savirin, a previously described AgrA inhibitor. However, staquorsin turned out to be superior over savarin in not affecting the S. aureus viability in concentrations up to 600 μM. On the other hand, savirin inhibited S. aureus growth in concentrations as low as 25 μM. Moreover, staquorsin proved to be a potent inhibitor of the Agr system by inhibiting hemolysins, lipase production, and affecting biofilms formation and detachment. On the molecular level it significantly inhibited the effector transcript RNA III. In vivo testing, using the murine skin abscess model, confirmed the ability of staquorsin to modulate S. aureus virulence by effectively controlling the infection. Twenty passages of S. aureus in the presence of 40 μM staquorsin have not resulted in loss of activity as evidenced by maintaining its ability to reduce hemolysin production and RNA III transcript levels. In conclusion, we hereby describe a novel anti-virulence compound inhibiting the S. aureus Agr-system and its associated virulence factors. It is active both in vitro and in vivo, and its frequent use does not lead to the development of resistance. These findings model staquorsin as a promising drug candidate to join the fierce battle against the formidable pathogen S. aureus.
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Affiliation(s)
- Norhan H Mahdally
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Riham F George
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Mona T Kashef
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Medhat Al-Ghobashy
- Department of Analytical Chemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt.,School of Pharmacy, Newgiza University, Giza, Egypt
| | - Fathia E Murad
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Ahmed S Attia
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
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105
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Salam AM, Porras G, Cho YSK, Brown MM, Risener CJ, Marquez L, Lyles JT, Bacsa J, Horswill AR, Quave CL. Castaneroxy A From the Leaves of Castanea sativa Inhibits Virulence in Staphylococcus aureus. Front Pharmacol 2021; 12:640179. [PMID: 34262448 PMCID: PMC8274328 DOI: 10.3389/fphar.2021.640179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 06/01/2021] [Indexed: 01/05/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) represents one of the most serious infectious disease concerns worldwide, with the CDC labeling it a "serious threat" in 2019. The current arsenal of antibiotics works by targeting bacterial growth and survival, which exerts great selective pressure for the development of resistance. The development of novel anti-infectives that inhibit quorum sensing and thus virulence in MRSA has been recurrently proposed as a promising therapeutic approach. In a follow-up of a study examining the MRSA quorum sensing inhibitory activity of extracts of Italian plants used in local traditional medicine, 224C-F2 was reported as a bioactive fraction of a Castanea sativa (European chestnut) leaf extract. The fraction demonstrated high activity in vitro and effective attenuation of MRSA pathogenicity in a mouse model of skin infection. Through further bioassay-guided fractionation using reverse-phase high performance liquid chromatography, a novel hydroperoxy cycloartane triterpenoid, castaneroxy A (1), was isolated. Its structure was established by nuclear magnetic resonance, mass spectrometry and X-ray diffraction analyses. Isomers of 1 were also detected in an adjacent fraction. In a series of assays assessing inhibition of markers of MRSA virulence, 1 exerted activities in the low micromolar range. It inhibited agr::P3 activation (IC50 = 31.72 µM), δ-toxin production (IC50 = 31.72 µM in NRS385), supernatant cytotoxicity to HaCaT human keratinocytes (IC50 = 7.93 µM in NRS385), and rabbit erythrocyte hemolytic activity (IC50 = 7.93 µM in LAC). Compound 1 did not inhibit biofilm production, and at high concentrations it exerted cytotoxicity against human keratinocytes greater than that of 224C-F2. Finally, 1 reduced dermonecrosis in a murine model of MRSA infection. The results establish 1 as a promising antivirulence candidate for development against MRSA.
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Affiliation(s)
- Akram M Salam
- Program in Molecular and Systems Pharmacology, Laney Graduate School, Emory University, Atlanta, GA, United States
| | - Gina Porras
- Center for the Study of Human Health, Emory University, Atlanta, GA, United States
| | - Young-Saeng K Cho
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Morgan M Brown
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Caitlin J Risener
- Program in Molecular and Systems Pharmacology, Laney Graduate School, Emory University, Atlanta, GA, United States
| | - Lewis Marquez
- Program in Molecular and Systems Pharmacology, Laney Graduate School, Emory University, Atlanta, GA, United States
| | - James T Lyles
- Center for the Study of Human Health, Emory University, Atlanta, GA, United States
| | - John Bacsa
- Department of Chemistry, Emory University, Atlanta, GA, United States
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Cassandra L Quave
- Center for the Study of Human Health, Emory University, Atlanta, GA, United States.,Department of Dermatology, Emory University School of Medicine, Atlanta, GA, United States.,Antibiotic Resistance Center, Emory University, Atlanta, GA, United States
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106
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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: 1.8] [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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107
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West KHJ, Shen W, Eisenbraun EL, Yang T, Vasquez JK, Horswill AR, Blackwell HE. Non-Native Peptides Capable of Pan-Activating the agr Quorum Sensing System across Multiple Specificity Groups of Staphylococcus epidermidis. ACS Chem Biol 2021; 16:1070-1078. [PMID: 33988969 DOI: 10.1021/acschembio.1c00240] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Staphylococcus epidermidis is a leading cause of hospital-acquired infections. Traditional antibiotics have significantly reduced efficacy against this pathogen due to its ability to form biofilms on abiotic surfaces and drug resistance. The accessory gene regulator (agr) quorum sensing system is directly involved in S. epidermidis pathogenesis. Activation of agr is achieved via binding of the autoinducing peptide (AIP) signal to the extracellular sensor domain of its cognate receptor, AgrC. Divergent evolution has given rise to four agr specificity groups in S. epidermidis defined by the unique AIP sequence used by each group (AIPs-I-IV) with observed cross-group activities. As agr agonism has been shown to reduce biofilm growth in S. epidermidis, the development of pan-group activators of the agr system is of interest as a potential antivirulence strategy. To date, no synthetic compounds have been identified that are capable of appreciably activating the agr system of more than one specificity group of S. epidermidis or, to our knowledge, of any of the other Staphylococci. Here, we report the characterization of the structure-activity relationships for agr agonism by S. epidermidis AIP-II and AIP-III and the application of these new SAR data and those previously reported for AIP-I for the design and synthesis of the first multigroup agr agonists. These non-native peptides were capable of inducing the expression of critical biofilm dispersal agents (i.e., phenol-soluble modulins) in cell culture and represent new tools to study the role of quorum sensing in S. epidermidis infections.
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Affiliation(s)
- Korbin H. J. West
- Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Wenqi Shen
- Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Emma L. Eisenbraun
- Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Tian Yang
- Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Joseph K. Vasquez
- Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Alexander R. Horswill
- Department of Immunology and Microbiology, Anschutz Medical Campus, University of Colorado, Aurora, Colorado 80045, United States
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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108
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Boyd NK, Teng C, Frei CR. Brief Overview of Approaches and Challenges in New Antibiotic Development: A Focus On Drug Repurposing. Front Cell Infect Microbiol 2021; 11:684515. [PMID: 34079770 PMCID: PMC8165386 DOI: 10.3389/fcimb.2021.684515] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 05/04/2021] [Indexed: 12/19/2022] Open
Abstract
Drug repurposing, or identifying new uses for existing drugs, has emerged as an alternative to traditional drug discovery processes involving de novo synthesis. Drugs that are currently approved or under development for non-antibiotic indications may possess antibiotic properties, and therefore may have repurposing potential, either alone or in combination with an antibiotic. They might also serve as "antibiotic adjuvants" to enhance the activity of certain antibiotics.
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Affiliation(s)
- Natalie K Boyd
- College of Pharmacy, The University of Texas at Austin, San Antonio, TX, United States.,Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Chengwen Teng
- Department of Clinical Pharmacy and Outcomes Sciences, College of Pharmacy, The University of South Carolina, Columbia, SC, United States
| | - Christopher R Frei
- College of Pharmacy, The University of Texas at Austin, San Antonio, TX, United States.,Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, United States.,Research Department, South Texas Veterans Health Care System, San Antonio, TX, United States.,Pharmacy Department, University Health System, San Antonio, TX, United States
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109
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Lade H, Kim JS. Bacterial Targets of Antibiotics in Methicillin-Resistant Staphylococcus aureus. Antibiotics (Basel) 2021; 10:398. [PMID: 33917043 PMCID: PMC8067735 DOI: 10.3390/antibiotics10040398] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 12/17/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most prevalent bacterial pathogens and continues to be a leading cause of morbidity and mortality worldwide. MRSA is a commensal bacterium in humans and is transmitted in both community and healthcare settings. Successful treatment remains a challenge, and a search for new targets of antibiotics is required to ensure that MRSA infections can be effectively treated in the future. Most antibiotics in clinical use selectively target one or more biochemical processes essential for S. aureus viability, e.g., cell wall synthesis, protein synthesis (translation), DNA replication, RNA synthesis (transcription), or metabolic processes, such as folic acid synthesis. In this review, we briefly describe the mechanism of action of antibiotics from different classes and discuss insights into the well-established primary targets in S. aureus. Further, several components of bacterial cellular processes, such as teichoic acid, aminoacyl-tRNA synthetases, the lipid II cycle, auxiliary factors of β-lactam resistance, two-component systems, and the accessory gene regulator quorum sensing system, are discussed as promising targets for novel antibiotics. A greater molecular understanding of the bacterial targets of antibiotics has the potential to reveal novel therapeutic strategies or identify agents against antibiotic-resistant pathogens.
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Affiliation(s)
| | - Jae-Seok Kim
- Department of Laboratory Medicine, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul 05355, Korea;
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110
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Williams MR, Cau L, Wang Y, Kaul D, Sanford JA, Zaramela LS, Khalil S, Butcher AM, Zengler K, Horswill AR, Dupont CL, Hovnanian A, Gallo RL. Interplay of Staphylococcal and Host Proteases Promotes Skin Barrier Disruption in Netherton Syndrome. Cell Rep 2021; 30:2923-2933.e7. [PMID: 32130897 PMCID: PMC7183042 DOI: 10.1016/j.celrep.2020.02.021] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/04/2019] [Accepted: 02/05/2020] [Indexed: 01/09/2023] Open
Abstract
Netherton syndrome (NS) is a monogenic skin disease resulting from loss of function of lymphoepithelial Kazal-type-related protease inhibitor (LEKTI-1). In this study we examine if bacteria residing on the skin are influenced by the loss of LEKTI-1 and if interaction between this human gene and resident bacteria contributes to skin disease. Shotgun sequencing of the skin microbiome demonstrates that lesional skin of NS subjects is dominated by Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis). Isolates of either species from NS subjects are able to induce skin inflammation and barrier damage on mice. These microbes promote skin inflammation in the setting of LEKTI-1 deficiency due to excess proteolytic activity promoted by S. aureus phenol-soluble modulin α as well as increased bacterial proteases staphopain A and B from S. aureus or EcpA from S. epidermidis. These findings demonstrate the critical need for maintaining homeostasis of host and microbial proteases to prevent a human skin disease.
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Affiliation(s)
- Michael R Williams
- Department of Dermatology, University of California, San Diego, San Diego, CA 92093, USA.
| | - Laura Cau
- Department of Dermatology, University of California, San Diego, San Diego, CA 92093, USA; SILAB, R&D Department, Brive, France.
| | - Yichen Wang
- INSERM, UMR 1163, Laboratory of Genetic Skin Diseases, Imagine Institute and Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Drishti Kaul
- J. Craig Venter Institute, La Jolla, CA 92093, USA
| | - James A Sanford
- Department of Dermatology, University of California, San Diego, San Diego, CA 92093, USA
| | - Livia S Zaramela
- Department of Pediatrics, University of California, San Diego, San Diego, CA 92093, USA
| | - Shadi Khalil
- Department of Dermatology, University of California, San Diego, San Diego, CA 92093, USA; University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Anna M Butcher
- Department of Dermatology, University of California, San Diego, San Diego, CA 92093, USA
| | - Karsten Zengler
- Department of Pediatrics, University of California, San Diego, San Diego, CA 92093, USA; Center for Microbiome Innovation, University of California, San Diego, San Diego, CA 92093, USA; Department of Bioengineering, University of California, San Diego, CA 92093, USA
| | - Alexander R Horswill
- Department of Veterans Affairs Denver Health Care System, Denver, CO, USA; Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora 80045, CO, USA
| | | | - Alain Hovnanian
- INSERM, UMR 1163, Laboratory of Genetic Skin Diseases, Imagine Institute and Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Richard L Gallo
- Department of Dermatology, University of California, San Diego, San Diego, CA 92093, USA; Center for Microbiome Innovation, University of California, San Diego, San Diego, CA 92093, USA.
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111
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Palaniappan B, Solomon AP, C DR. Targeting AgrA quorum sensing regulator by bumetanide attenuates virulence in Staphylococcus aureus - A drug repurposing approach. Life Sci 2021; 273:119306. [PMID: 33662434 DOI: 10.1016/j.lfs.2021.119306] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/23/2021] [Accepted: 02/24/2021] [Indexed: 11/29/2022]
Abstract
AIMS The present study aims to target the quorum sensing (QS) accessory gene regulator A (AgrA) of Staphylococcus aureus to curtail bacterial virulence through drug repurposing approach. MAIN METHODS In silico screening of chemical ligands that bind specifically to the S. aureus C-LytTR domain of AgrA (AgrAC) was carried out. AgrA inhibition and downregulation of virulence genes linked to QS system of S. aureus were determined. Efficacy, dermal toxicity and drug tolerance induction were tested in Balb/C mice dermonecrosis model. KEY FINDINGS Bumetanide bound to the conserved amino acid Tyr-229 of AgrA and showed 70% AgrA inhibition at 0.1 μM. Highly significant reduction in the expression of representative virulence genes such as alpha-hemolysin (~5 log2-fold), phenol-soluble modulins (~4 log2-fold) and panton-valentine leukocidin (~3 log2-fold) was noted in vitro. In vivo studies signified bumetanide to be highly effective in controlling the ulcer development and promoted wound healing. Also, the tested substance did not have dermal toxicity and no tolerance induction as well. SIGNIFICANCE Targeting the QS regulators could be a possible alternative approach to curtail virulence in S. aureus. In addition, if the QS inhibitors are repurposed it could accelerate the drug development process and reduce the cost. The identified drug bumetanide inhibited AgrA and the results were in comparable to that of a known virulence inhibitor, diflunisal. The newly reported results of bumetanide in this study are expected to mark the drug's visibility for antibiotic adjunctive therapy and topical drug formulations for skin infections research.
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Affiliation(s)
- Balamurugan Palaniappan
- Quorum Sensing Laboratory, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India.
| | - Adline Princy Solomon
- Quorum Sensing Laboratory, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India.
| | - David Raj C
- Central Animal Facility, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
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112
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Cheung GYC, Bae JS, Liu R, Hunt RL, Zheng Y, Otto M. Bacterial virulence plays a crucial role in MRSA sepsis. PLoS Pathog 2021; 17:e1009369. [PMID: 33630954 PMCID: PMC7942999 DOI: 10.1371/journal.ppat.1009369] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 03/09/2021] [Accepted: 02/10/2021] [Indexed: 12/29/2022] Open
Abstract
Bacterial sepsis is a major global cause of death. However, the pathophysiology of sepsis has remained poorly understood. In industrialized nations, Staphylococcus aureus represents the pathogen most commonly associated with mortality due to sepsis. Because of the alarming spread of antibiotic resistance, anti-virulence strategies are often proposed to treat staphylococcal sepsis. However, we do not yet completely understand if and how bacterial virulence contributes to sepsis, which is vital for a thorough assessment of such strategies. We here examined the role of virulence and quorum-sensing regulation in mouse and rabbit models of sepsis caused by methicillin-resistant S. aureus (MRSA). We determined that leukopenia was a predictor of disease outcome during an early critical stage of sepsis. Furthermore, in device-associated infection as the most frequent type of staphylococcal blood infection, quorum-sensing deficiency resulted in significantly higher mortality. Our findings give important guidance regarding anti-virulence drug development strategies for the treatment of staphylococcal sepsis. Moreover, they considerably add to our understanding of how bacterial sepsis develops by revealing a critical early stage of infection during which the battle between bacteria and leukocytes determines sepsis outcome. While sepsis has traditionally been attributed mainly to host factors, our study highlights a key role of the invading pathogen and its virulence mechanisms.
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Affiliation(s)
- Gordon Y. C. Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Justin S. Bae
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ryan Liu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Rachelle L. Hunt
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yue Zheng
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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113
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Rungelrath V, DeLeo FR. Staphylococcus aureus, Antibiotic Resistance, and the Interaction with Human Neutrophils. Antioxid Redox Signal 2021; 34:452-470. [PMID: 32460514 PMCID: PMC8020508 DOI: 10.1089/ars.2020.8127] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Significance:Staphylococcus aureus is among the leading causes of bacterial infections worldwide. The high burden of S. aureus among human and animal hosts, which includes asymptomatic carriage and infection, is coupled with a notorious ability of the microbe to become resistant to antibiotics. Notably, S. aureus has the ability to produce molecules that promote evasion of host defense, including the ability to avoid killing by neutrophils. Recent Advances: Significant progress has been made to better understand S. aureus-host interactions. These discoveries include elucidation of the role played by numerous S. aureus virulence molecules during infection. Based on putative functions, a number of these virulence molecules, including S. aureus alpha-hemolysin and protein A, have been identified as therapeutic targets. Although it has not been possible to develop a vaccine that can prevent S. aureus infections, monoclonal antibodies specific for S. aureus virulence molecules have the potential to moderate the severity of disease. Critical Issues: Therapeutic options for treatment of methicillin-resistant S. aureus (MRSA) are limited, and the microbe typically develops resistance to new antibiotics. New prophylactics and/or therapeutics are needed. Future Directions: Research that promotes an enhanced understanding of S. aureus-host interaction is an important step toward developing new therapeutic approaches directed to moderate disease severity and facilitate treatment of infection. This research effort includes studies that enhance our view of the interaction of S. aureus with human neutrophils. Antioxid. Redox Signal. 34, 452-470.
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Affiliation(s)
- Viktoria Rungelrath
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Frank R DeLeo
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
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114
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Stoica C, Cox G. Old problems and new solutions: antibiotic alternatives in food animal production. Can J Microbiol 2021; 67:427-444. [PMID: 33606564 DOI: 10.1139/cjm-2020-0601] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The antimicrobial resistance crisis is a Global Health challenge that impacts humans, animals, and the environment alike. In response to increased demands for animal protein and by-products, there has been a substantial increase in the use of antimicrobial agents in the animal industry. Indeed, they are extensively used to prevent, control, and (or) treat disease in animals. In addition to infection control, in-feed supplementation with antimicrobials became common practice for growth promotion of livestock. Unfortunately, the global overuse of antimicrobials has contributed to the emergence and spread of resistance. As such, many countries have implemented policies and approaches to eliminate the use of antimicrobials as growth promoters in food animals, which necessitates the need for alternate and One Health strategies to maintain animal health and welfare. This review summarizes the antimicrobial resistance crisis from Global Health and One Health perspectives. In addition, we outline examples of potential alternate strategies to circumvent antimicrobial use in animal husbandry practices, including antivirulence agents, bacteriophages, and nutritional measures to control bacterial pathogens. Overall, these alternate strategies require further research and development efforts, including assessment of efficacy and the associated development, manufacturing, and labor costs.
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Affiliation(s)
- Celine Stoica
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada.,Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Georgina Cox
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada.,Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
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115
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Potential role of probiotics in reducing Clostridioides difficile virulence: Interference with quorum sensing systems. Microb Pathog 2021; 153:104798. [PMID: 33609647 DOI: 10.1016/j.micpath.2021.104798] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 12/23/2022]
Abstract
Opportunistic pathogenic bacteria may cause disease after the normally protective microbiome is disrupted (typically by antibiotic exposure). Clostridioides difficile is one such pathogen having a severe impact on healthcare facilities and increasing costs of medical care. The search for new therapeutic strategies that are not reliant on additional antibiotic exposures are currently being explored. One such strategy is to disrupt the production of C. difficile virulence factors by interfering with quorum sensing (QS) systems. QS has been well studied in other bacteria, but our understanding in C. difficile is not so well understood. Some probiotic strains or combinations of strains have been shown to be effective in the treatment or primary prevention of C. difficile infections and may possess multiple mechanisms of action. One mechanism of probiotics might be the inhibition of QS, but their role has not been clearly defined yet. A literature search was conducted using standard databases (PubMed, Google Scholar) from database inception to August 2020. The objective of this paper is to update our understanding of how QS leads to toxin production by C. difficile, which is important in pathogenesis, and how QS inhibitors or probiotics may disrupt this pathway. We found two main QS systems for C. difficile (Agr and Lux systems) that are involved in C. difficile pathogenesis by regulating toxin production, motility and adherence. Probiotics and other QS inhibitors targeting QS systems may represent important new directions of therapy and prevention of CDI.
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116
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Bernabè G, Dal Pra M, Ronca V, Pauletto A, Marzaro G, Saluzzo F, Stefani A, Artusi I, De Filippis V, Ferlin MG, Brun P, Castagliuolo I. A Novel Aza-Derivative Inhibits agr Quorum Sensing Signaling and Synergizes Methicillin-Resistant Staphylococcus aureus to Clindamycin. Front Microbiol 2021; 12:610859. [PMID: 33633702 PMCID: PMC7899991 DOI: 10.3389/fmicb.2021.610859] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 01/15/2021] [Indexed: 01/21/2023] Open
Abstract
Increasing antibiotic resistance and diminishing pharmaceutical industry investments have increased the need for molecules that can treat infections caused by dangerous pathogens such as methicillin-resistant Staphylococcus aureus (MRSA). Quorum Sensing (QS) is a signaling mechanism that regulates bacterial virulence in pathogens. A report demonstrating that the anti-inflammatory drug Diflunisal reduces MRSA virulence factors' expression prompted us to design, synthesize and test 16 aza-analogs as inhibitors of S. aureus virulence factors controlled by the accessory gene regulator (agr) QS system. At first, we evaluated by qRT-PCR the activity of compounds on rnaIII expression, a QS related gene. Azan-7 was the most active molecule tested and it did not show cytotoxic activity in human cell lines. Moreover, we demonstrated that it did not affect bacterial proliferation. Regulation of MRSA virulence genes by Azan-7 was investigated using qRT-PCR and RNAseq. Azan-7 significantly reduced hla, psmα, hysA, agrA, cap1A, and cap1C gene expression. In silico docking demonstrated that Azan-7 binds the response regulator AgrA. This data was confirmed by electrophoretic mobility shift assay (EMSA) reporting that Azan-7 binding to AgrA protein strongly reduced the AgrA-DNA complex formation at the P3 promoter region involved in the regulation of rnaIII transcription. Azan-7 inhibited MRSA-mediated haemolysis, reduced survival of the pathogen at low pH levels, and increased macrophage killing. In addition, Azan-7 enhanced MRSA susceptibility to clindamycin both in planktonic growth and biofilm. Azan-7 did not induce resistance over 10 days in culture. It was equally active against all the AgrA MRSA subtypes encountered among clinical isolates, but it was not active against Staphylococcus epidermidis, although the AgrA proteins show an approximate 80% homology. These results demonstrate that Azan-7 inhibits the expression of MRSA virulence factors by interfering in the QS and synergizes MRSA biofilm with clindamycin, indicating the compound as a promising candidate for the treatment of MRSA infections.
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Affiliation(s)
- Giulia Bernabè
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Matteo Dal Pra
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Vittoria Ronca
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Anthony Pauletto
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Giovanni Marzaro
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | | | - Annalisa Stefani
- Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| | - Ilaria Artusi
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Vincenzo De Filippis
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Maria Grazia Ferlin
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Paola Brun
- Department of Molecular Medicine, University of Padua, Padua, Italy
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117
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França A, Gaio V, Lopes N, Melo LDR. Virulence Factors in Coagulase-Negative Staphylococci. Pathogens 2021; 10:170. [PMID: 33557202 PMCID: PMC7913919 DOI: 10.3390/pathogens10020170] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/29/2021] [Accepted: 01/29/2021] [Indexed: 12/13/2022] Open
Abstract
Coagulase-negative staphylococci (CoNS) have emerged as major pathogens in healthcare-associated facilities, being S. epidermidis, S. haemolyticus and, more recently, S. lugdunensis, the most clinically relevant species. Despite being less virulent than the well-studied pathogen S. aureus, the number of CoNS strains sequenced is constantly increasing and, with that, the number of virulence factors identified in those strains. In this regard, biofilm formation is considered the most important. Besides virulence factors, the presence of several antibiotic-resistance genes identified in CoNS is worrisome and makes treatment very challenging. In this review, we analyzed the different aspects involved in CoNS virulence and their impact on health and food.
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Affiliation(s)
- Angela França
- Laboratory of Research in Biofilms Rosário Oliveira, Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal; (V.G.); (N.L.)
| | | | | | - Luís D. R. Melo
- Laboratory of Research in Biofilms Rosário Oliveira, Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal; (V.G.); (N.L.)
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118
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Ford CA, Hurford IM, Cassat JE. Antivirulence Strategies for the Treatment of Staphylococcus aureus Infections: A Mini Review. Front Microbiol 2021; 11:632706. [PMID: 33519793 PMCID: PMC7840885 DOI: 10.3389/fmicb.2020.632706] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 12/22/2020] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus is a Gram-positive bacterium capable of infecting nearly all host tissues, causing severe morbidity and mortality. Widespread antimicrobial resistance has emerged among S. aureus clinical isolates, which are now the most frequent causes of nosocomial infection among drug-resistant pathogens. S. aureus produces an array of virulence factors that enhance in vivo fitness by liberating nutrients from the host or evading host immune responses. Staphylococcal virulence factors have been identified as viable therapeutic targets for treatment, as they contribute to disease pathogenesis, tissue injury, and treatment failure. Antivirulence strategies, or treatments targeting virulence without direct toxicity to the inciting pathogen, show promise as an adjunctive therapy to traditional antimicrobials. This Mini Review examines recent research on S. aureus antivirulence strategies, with an emphasis on translational studies. While many different virulence factors have been investigated as therapeutic targets, this review focuses on strategies targeting three virulence categories: pore-forming toxins, immune evasion mechanisms, and the S. aureus quorum sensing system. These major areas of S. aureus antivirulence research demonstrate broad principles that may apply to other human pathogens. Finally, challenges of antivirulence research are outlined including the potential for resistance, the need to investigate multiple infection models, and the importance of studying antivirulence in conjunction with traditional antimicrobial treatments.
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Affiliation(s)
- Caleb A. Ford
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States
| | - Ian M. Hurford
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN, United States
| | - James E. Cassat
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN, United States
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States
- Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN, United States
- Vanderbilt Institute for Infection, Immunology, and Inflammation (VI4), Vanderbilt University Medical Center, Nashville, TN, United States
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119
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2-(2-Methyl-2-nitrovinyl)furan but Not Furvina Interfere with Staphylococcus aureus Agr Quorum-Sensing System and Potentiate the Action of Fusidic Acid against Biofilms. Int J Mol Sci 2021; 22:ijms22020613. [PMID: 33435417 PMCID: PMC7827229 DOI: 10.3390/ijms22020613] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/31/2020] [Accepted: 01/06/2021] [Indexed: 11/16/2022] Open
Abstract
Quorum sensing (QS) plays an essential role in the production of virulence factors, in biofilm formation and antimicrobial resistance. Consequently, inhibiting QS is being considered a promising target for antipathogenic/anti-virulence therapies. This study aims to screen 2-nitrovinylfuran derivatives structurally related to Furvina (a broad-spectrum antibiotic already used for therapeutic purposes) for their effects on QS and in biofilm prevention/control. Furvina and four 2-nitrovinylfuran derivatives (compounds 1–4) were tested to assess the ability to interfere with QS of Staphylococcus aureus using bioreporter strains (S. aureus ALC1742 and ALC1743). The activity of Furvina and the most promising quorum-sensing inhibitor (QSI) was evaluated in biofilm prevention and in biofilm control (combined with fusidic acid). The biofilms were further characterized in terms of biofilm mass, viability and membrane integrity. Compound 2 caused the most significant QS inhibition with reductions between 60% and 80%. Molecular docking simulations indicate that this compound interacts preferentially with the protein hydrophobic cleft in the LytTR domain of AgrA pocket. Metabolic inactivations of 40% for S. aureus ALC1742 and 20% for S. aureus ALC1743 were reached. A 24 h-old biofilm formed in the presence of the QSI increased the metabolic inactivation by fusidic acid to 80%, for both strains. The overall results highlight the effects of compound 2 as well as the potential of combining QSI with in-use antibiotics for the management of skin and soft tissues infections.
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120
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Li P, Gao Z, Tan Z, Xiao J, Wei L, Chen Y. New developments in anti-biofilm intervention towards effective management of orthopedic device related infections (ODRI's). BIOFOULING 2021; 37:1-35. [PMID: 33618584 DOI: 10.1080/08927014.2020.1869725] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 12/15/2020] [Accepted: 12/20/2020] [Indexed: 06/12/2023]
Abstract
Orthopedic device related infections (ODRI's) represent a difficult to treat situation owing to their biofilm based nature. Biofilm infections once established are difficult to eradicate even with an aggressive treatment regimen due to their recalcitrance towards antibiotics and immune attack. The involvement of antibiotic resistant pathogens as the etiological agent further worsens the overall clinical picture, pressing on the need to look into alternative treatment strategies. The present review highlightes the microbiological challenges associated with treatment of ODRI's due to biofilm formation on the implant surface. Further, it details the newer anti-infective modalities that work either by preventing biofilm formation and/or through effective disruption of the mature biofilms formed on the medical implant. The study, therefore aims to provide a comprehensive insight into the newer anti-biofilm interventions (non-antibiotic approaches) and a better understanding of their mechanism of action essential for improved management of orthopedic implant infections.
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Affiliation(s)
- Ping Li
- Department of Orthopedics, Ya'an People's Hospital, Yaan City, China
| | - Zhenwu Gao
- Department of Orthopedics, Shanxi Bethune Hospital, Taiyuan City, China
| | - Zhenwei Tan
- Department of Orthopedics, Western Theater Air Force Hospital of PLA, Chengdu, China
| | - Jun Xiao
- Department of Orthopedics, Ya'an People's Hospital, Yaan City, China
| | - Li Wei
- Nursing Department, Three Gorges Hospital Affiliated to Chongqing University, Chongqing, China
| | - Yirui Chen
- Department of Orthopedics, Three Gorges Hospital Affiliated to Chongqing University, Chongqing, China
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121
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Van Belleghem JD, Manasherob R, Miȩdzybrodzki R, Rogóż P, Górski A, Suh GA, Bollyky PL, Amanatullah DF. The Rationale for Using Bacteriophage to Treat and Prevent Periprosthetic Joint Infections. Front Microbiol 2020; 11:591021. [PMID: 33408703 PMCID: PMC7779626 DOI: 10.3389/fmicb.2020.591021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 11/24/2020] [Indexed: 12/19/2022] Open
Abstract
Prosthetic joint infection (PJI) is a devastating complication after a joint replacement. PJI and its treatment have a high monetary cost, morbidity, and mortality. The lack of success treating PJI with conventional antibiotics alone is related to the presence of bacterial biofilm on medical implants. Consequently, surgical removal of the implant and prolonged intravenous antibiotics to eradicate the infection are necessary prior to re-implanting a new prosthetic joint. Growing clinical data shows that bacterial predators, called bacteriophages (phages), could be an alternative treatment strategy or prophylactic approach for PJI. Phages could further be exploited to degrade biofilms, making bacteria more susceptible to antibiotics and enabling potential combinatorial therapies. Emerging research suggests that phages may also directly interact with the innate immune response. Phage therapy may play an important, and currently understudied, role in the clearance of PJI, and has the potential to treat thousands of patients who would either have to undergo revision surgery to attempt to clear an infections, take antibiotics for a prolonged period to try and suppress the re-emerging infection, or potentially risk losing a limb.
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Affiliation(s)
- Jonas D. Van Belleghem
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
| | - Robert Manasherob
- Department of Orthopaedic Surgery, Stanford University, Stanford, CA, United States
| | - Ryszard Miȩdzybrodzki
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Paweł Rogóż
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Andrzej Górski
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | | | - Paul L. Bollyky
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
| | - Derek F. Amanatullah
- Department of Orthopaedic Surgery, Stanford University, Stanford, CA, United States
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122
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Thurlow LR, Stephens AC, Hurley KE, Richardson AR. Lack of nutritional immunity in diabetic skin infections promotes Staphylococcus aureus virulence. SCIENCE ADVANCES 2020; 6:6/46/eabc5569. [PMID: 33188027 PMCID: PMC7673755 DOI: 10.1126/sciadv.abc5569] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 09/29/2020] [Indexed: 05/22/2023]
Abstract
Elevated blood/tissue glucose is a hallmark feature of advanced diabetes, and people with diabetes are prone to more frequent and invasive infections with Staphylococcus aureus. Phagocytes must markedly increase glucose consumption during infection to generate and oxidative burst and kill invading bacteria. Similarly, glucose is essential for S. aureus survival in an infection and competition with the host, for this limited resource is reminiscent of nutritional immunity. Here, we show that infiltrating phagocytes do not express their high-efficiency glucose transporters in modeled diabetic infections, resulting in a diminished respiratory burst and increased glucose availability for S. aureus We show that excess glucose in these hyperglycemic abscesses significantly enhances S. aureus virulence potential, resulting in worse infection outcomes. Last, we show that two glucose transporters recently acquired by S. aureus are essential for excess virulence factor production and the concomitant increase in disease severity in hyperglycemic infections.
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Affiliation(s)
- Lance R Thurlow
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Amelia C Stephens
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Kelly E Hurley
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Anthony R Richardson
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA.
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123
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Kongkham B, Prabakaran D, Puttaswamy H. Opportunities and challenges in managing antibiotic resistance in bacteria using plant secondary metabolites. Fitoterapia 2020; 147:104762. [PMID: 33069839 DOI: 10.1016/j.fitote.2020.104762] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 10/08/2020] [Accepted: 10/12/2020] [Indexed: 12/11/2022]
Abstract
Development of antibiotic resistance (ABR) in bacteria and its multidimensional spread is an emerging global threat that needs immediate attention. Extensive antibiotics (AB) usage results in development of ABR in bacteria by target modification, production of AB degrading enzymes, porin modifications, efflux pumps overexpression, etc. To counter this, apart from strict regulation of AB use and behavioural changes, research and development (R&D) of newer antimicrobials are in place. One such emerging approach to combat ABR is the use of structurally and functionally diverse plant secondary metabolites (PSMs) in combination with the conventional AB. Either the PSMs are themselves antimicrobial or they potentiate the activity of the AB through a range of mechanisms. However, their use is lagging due to poor knowledge of mode of action, structure-activity relationships, pharmacokinetics, etc. This review paper discussed the opportunities and challenges in managing ABR using PSMs. Mechanisms of ABR development in bacteria and current strategies to counter them were studied and the areas where PSMs can play an important role were highlighted. The use of PSMs, both as an anti-resistance and anti-virulence agent in combination therapy to counter multi-drug resistance along with their mechanisms of action, has been discussed in detail. The difficulties in the commercialisation of PSMs and strategies to overcome them along with future priority areas of research have also been given. Following the given R&D path will definitely help in better understanding and utilising the full potential of PSMs in solving the problem of antimicrobial resistance (AMR).
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Affiliation(s)
- Bhani Kongkham
- Environmental Biotechnology Laboratory, Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Delhi 110016, India
| | - Duraivadivel Prabakaran
- Environmental Biotechnology Laboratory, Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Delhi 110016, India
| | - Hariprasad Puttaswamy
- Environmental Biotechnology Laboratory, Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Delhi 110016, India.
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124
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Zhou L, Zhang Y, Ge Y, Zhu X, Pan J. Regulatory Mechanisms and Promising Applications of Quorum Sensing-Inhibiting Agents in Control of Bacterial Biofilm Formation. Front Microbiol 2020; 11:589640. [PMID: 33178172 PMCID: PMC7593269 DOI: 10.3389/fmicb.2020.589640] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/23/2020] [Indexed: 01/09/2023] Open
Abstract
A biofilm is an assemblage of microbial cells attached to a surface and encapsulated in an extracellular polymeric substance (EPS) matrix. The formation of a biofilm is one of the important mechanisms of bacterial resistance, which not only leads to hard-to-control bacterial infections in humans and animals but also enables bacteria to be a major problem in various fields, such as food processing, wastewater treatment and metalworking. Quorum sensing (QS) is a bacterial cell-to-cell communication process that depends on the bacterial population density and is mediated by small diffusible signaling molecules called autoinducers (AIs). Bacteria use QS to regulate diverse arrays of functions, including virulence and biofilm formation. Therefore, the interference with QS by using QS inhibiting agents, including QS inhibitors (QSIs) and quorum quenching (QQ) enzymes, to reduce or even completely repress the biofilm formation of pathogenic bacteria appears to be a promising approach to control bacterial infections. In this review, we summarize the mechanisms of QS-regulating biofilm formation and QS-inhibiting agents that control bacterial biofilm formation, strategies for the discovery of new QS inhibiting agents, and the current applications of QS-inhibiting agents in several fields to provide insight into the development of effective drugs to control pathogenic bacteria.
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Affiliation(s)
| | | | | | | | - Jianyi Pan
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
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125
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Biofilms in Diabetic Foot Ulcers: Significance and Clinical Relevance. Microorganisms 2020; 8:microorganisms8101580. [PMID: 33066595 PMCID: PMC7602394 DOI: 10.3390/microorganisms8101580] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 10/07/2020] [Accepted: 10/11/2020] [Indexed: 12/14/2022] Open
Abstract
Foot infections are the main disabling complication in patients with diabetes mellitus. These infections can lead to lower-limb amputation, increasing mortality and decreasing the quality of life. Biofilm formation is an important pathophysiology step in diabetic foot ulcers (DFU)-it plays a main role in the disease progression and chronicity of the lesion, the development of antibiotic resistance, and makes wound healing difficult to treat. The main problem is the difficulty in distinguishing between infection and colonization in DFU. The bacteria present in DFU are organized into functionally equivalent pathogroups that allow for close interactions between the bacteria within the biofilm. Consequently, some bacterial species that alone would be considered non-pathogenic, or incapable of maintaining a chronic infection, could co-aggregate symbiotically in a pathogenic biofilm and act synergistically to cause a chronic infection. In this review, we discuss current knowledge on biofilm formation, its presence in DFU, how the diabetic environment affects biofilm formation and its regulation, and the clinical implications.
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126
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Cobb LH, McCabe EM, Priddy LB. Therapeutics and delivery vehicles for local treatment of osteomyelitis. J Orthop Res 2020; 38:2091-2103. [PMID: 32285973 PMCID: PMC8117475 DOI: 10.1002/jor.24689] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 04/07/2020] [Accepted: 04/11/2020] [Indexed: 02/04/2023]
Abstract
Osteomyelitis, or the infection of the bone, presents a major complication in orthopedics and may lead to prolonged hospital visits, implant failure, and in more extreme cases, amputation of affected limbs. Typical treatment for this disease involves surgical debridement followed by long-term, systemic antibiotic administration, which contributes to the development of antibiotic-resistant bacteria and has limited ability to eradicate challenging biofilm-forming pathogens including Staphylococcus aureus-the most common cause of osteomyelitis. Local delivery of high doses of antibiotics via traditional bone cement can reduce systemic side effects of an antibiotic. Nonetheless, growing concerns over burst release (then subtherapeutic dose) of antibiotics, along with microbial colonization of the nondegradable cement biomaterial, further exacerbate antibiotic resistance and highlight the need to engineer alternative antimicrobial therapeutics and local delivery vehicles with increased efficacy against, in particular, biofilm-forming, antibiotic-resistant bacteria. Furthermore, limited guidance exists regarding both standardized formulation protocols and validated assays to predict efficacy of a therapeutic against multiple strains of bacteria. Ideally, antimicrobial strategies would be highly specific while exhibiting a broad spectrum of bactericidal activity. With a focus on S. aureus infection, this review addresses the efficacy of novel therapeutics and local delivery vehicles, as alternatives to the traditional antibiotic regimens. The aim of this review is to discuss these components with regards to long bone osteomyelitis and to encourage positive directions for future research efforts.
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Affiliation(s)
- Leah H. Cobb
- Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS, USA
| | - Emily M. McCabe
- Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS, USA,Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS, USA
| | - Lauren B. Priddy
- Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS, USA,corresponding author: Contact: , (662) 325-5988, Department of Agricultural and Biological Engineering, Mississippi State University, 130 Creelman Street, Mississippi State, MS, USA 39762
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Amin Yavari S, Castenmiller SM, van Strijp JAG, Croes M. Combating Implant Infections: Shifting Focus from Bacteria to Host. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2002962. [PMID: 32914481 DOI: 10.1002/adma.202002962] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/28/2020] [Indexed: 05/06/2023]
Abstract
The widespread use of biomaterials to support or replace body parts is increasingly threatened by the risk of implant-associated infections. In the quest for finding novel anti-infective biomaterials, there generally has been a one-sided focus on biomaterials with direct antibacterial properties, which leads to excessive use of antibacterial agents, compromised host responses, and unpredictable effectiveness in vivo. This review sheds light on how host immunomodulation, rather than only targeting bacteria, can endow biomaterials with improved anti-infective properties. How antibacterial surface treatments are at risk to be undermined by biomaterial features that dysregulate the protection normally provided by critical immune cell subsets, namely, neutrophils and macrophages, is discussed. Accordingly, how the precise modification of biomaterial surface biophysical cues, or the incorporation of immunomodulatory drug delivery systems, can render biomaterials with the necessary immune-compatible and immune-protective properties to potentiate the host defense mechanisms is reviewed. Within this context, the protective role of host defense peptides, metallic particles, quorum sensing inhibitors, and therapeutic adjuvants is discussed. The highlighted immunomodulatory strategies may lay a foundation to develop anti-infective biomaterials, while mitigating the increasing threat of antibacterial drug resistance.
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Affiliation(s)
- Saber Amin Yavari
- Department of Orthopedics, University Medical Center Utrecht, Utrecht, 3508GA, The Netherlands
| | - Suzanne M Castenmiller
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, 3508GA, The Netherlands
| | - Jos A G van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, 3508GA, The Netherlands
| | - Michiel Croes
- Department of Orthopedics, University Medical Center Utrecht, Utrecht, 3508GA, The Netherlands
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128
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Sun H, Pulakat L, Anderson DW. Challenges and New Therapeutic Approaches in the Management of Chronic Wounds. Curr Drug Targets 2020; 21:1264-1275. [PMID: 32576127 DOI: 10.2174/1389450121666200623131200] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 05/10/2020] [Accepted: 05/20/2020] [Indexed: 02/07/2023]
Abstract
Chronic non-healing wounds are estimated to cost the US healthcare $28-$31 billion per year. Diabetic ulcers, arterial and venous ulcers, and pressure ulcers are some of the most common types of chronic wounds. The burden of chronic wounds continues to rise due to the current epidemic of obesity and diabetes and the increase in elderly adults in the population who are more vulnerable to chronic wounds than younger individuals. This patient population is also highly vulnerable to debilitating infections caused by opportunistic and multi-drug resistant pathogens. Reduced microcirculation, decreased availability of cytokines and growth factors that promote wound closure and healing, and infections by multi-drug resistant and biofilm forming microbes are some of the critical factors that contribute to the development of chronic non-healing wounds. This review discusses novel approaches to understand chronic wound pathology and methods to improve chronic wound care, particularly when chronic wounds are infected by multi-drug resistant, biofilm forming microbes.
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Affiliation(s)
- Hongmin Sun
- Division of Cardiovascular Medicine, Department of Medicine, University of Missouri, Columbia, Missouri 65212, United States
| | - Lakshmi Pulakat
- Division of Cardiovascular Medicine, Department of Medicine, University of Missouri, Columbia, Missouri 65212, United States
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129
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Ellermann M, Sperandio V. Bacterial signaling as an antimicrobial target. Curr Opin Microbiol 2020; 57:78-86. [PMID: 32916624 DOI: 10.1016/j.mib.2020.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/29/2020] [Accepted: 08/03/2020] [Indexed: 12/12/2022]
Abstract
Antibiotics profoundly reduced worldwide mortality. However, the emergence of resistance to the growth inhibiting effects of these drugs occurred. New approaches to treat infectious disease that reduce the likelihood for resistance are needed. In bacterial pathogens, complex signaling networks regulate virulence. Anti-virulence therapies aim to disrupt these networks to attenuate virulence without affecting growth. Quorum-sensing, a cell-to-cell communication system, represents an attractive anti-virulence target because it often activates virulence. The challenge is to identify druggable targets that inhibit virulence, while also minimizing the likelihood of mutations promoting resistance. Moreover, given the ubiquity of quorum-sensing systems in commensals, any potential effects of anti-virulence therapies on microbiome function should also be considered. Here we highlight the efficacy and drawbacks of anti-virulence approaches.
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Affiliation(s)
- Melissa Ellermann
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Vanessa Sperandio
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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130
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Lei W, Demir K, Overhage J, Grunze M, Schwartz T, Levkin PA. Droplet-Microarray: Miniaturized Platform for High-Throughput Screening of Antimicrobial Compounds. ACTA ACUST UNITED AC 2020; 4:e2000073. [PMID: 32875737 DOI: 10.1002/adbi.202000073] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 07/20/2020] [Indexed: 01/12/2023]
Abstract
Currently, there are no time-saving and cost-effective high-throughput screening methods for the evaluation of bacterial drug-resistance. In this study, a droplet microarray (DMA) system is established as a miniaturized platform for high-throughput screening of antibacterial compounds using the emerging, opportunistic human pathogen Pseudomonas aeruginosa (P. aeruginosa) as a target. Based on the differences in wettability of DMA slides, a rapid method for generating microarrays of nanoliter-sized droplets containing bacteria is developed. The bacterial growth in droplets is evaluated using fluorescence. The new method enables immediate screening with libraries of antibiotics. A novel simple colorimetric readout method compatible with the nanoliter size of the droplets is established. Furthermore, the drug-resistance of P. aeruginosa 49, a multi-resistant strain from an environmental isolate, is investigated. This study demonstrates the potential of the DMA platform for the rapid formation of microarrays of bacteria for high-throughput drug screening.
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Affiliation(s)
- Wenxi Lei
- Institute of Biological and Chemical Systems-Functional Molecular Systems, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Platz 1, Eggenstein-Leopoldshafen, 76344, Germany
| | - Konstantin Demir
- Institute of Biological and Chemical Systems-Functional Molecular Systems, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Platz 1, Eggenstein-Leopoldshafen, 76344, Germany
| | - Joerg Overhage
- Department of Health Sciences, Carleton University, Ottawa, ON, K1S 5B6, Canada
| | - Michael Grunze
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, Heidelberg, 69120, Germany
| | - Thomas Schwartz
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Platz 1, Eggenstein-Leopoldshafen, 76344, Germany
| | - Pavel A Levkin
- Institute of Biological and Chemical Systems-Functional Molecular Systems, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Platz 1, Eggenstein-Leopoldshafen, 76344, Germany.,Institute of Organic Chemistry, Karlsruhe Institute of Technology, Karlsruhe, 76131, Germany
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131
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Quorum Sensing-Linked agrA Expression by Ethno-Synthesized Gold Nanoparticles in Tilapia Streptococcus agalactiae Biofilm Formation. BIONANOSCIENCE 2020. [DOI: 10.1007/s12668-020-00758-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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132
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Schilcher K, Horswill AR. Staphylococcal Biofilm Development: Structure, Regulation, and Treatment Strategies. Microbiol Mol Biol Rev 2020; 84:e00026-19. [PMID: 32792334 PMCID: PMC7430342 DOI: 10.1128/mmbr.00026-19] [Citation(s) in RCA: 352] [Impact Index Per Article: 70.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In many natural and clinical settings, bacteria are associated with some type of biotic or abiotic surface that enables them to form biofilms, a multicellular lifestyle with bacteria embedded in an extracellular matrix. Staphylococcus aureus and Staphylococcus epidermidis, the most frequent causes of biofilm-associated infections on indwelling medical devices, can switch between an existence as single free-floating cells and multicellular biofilms. During biofilm formation, cells first attach to a surface and then multiply to form microcolonies. They subsequently produce the extracellular matrix, a hallmark of biofilm formation, which consists of polysaccharides, proteins, and extracellular DNA. After biofilm maturation into three-dimensional structures, the biofilm community undergoes a disassembly process that leads to the dissemination of staphylococcal cells. As biofilms are dynamic and complex biological systems, staphylococci have evolved a vast network of regulatory mechanisms to modify and fine-tune biofilm development upon changes in environmental conditions. Thus, biofilm formation is used as a strategy for survival and persistence in the human host and can serve as a reservoir for spreading to new infection sites. Moreover, staphylococcal biofilms provide enhanced resilience toward antibiotics and the immune response and impose remarkable therapeutic challenges in clinics worldwide. This review provides an overview and an updated perspective on staphylococcal biofilms, describing the characteristic features of biofilm formation, the structural and functional properties of the biofilm matrix, and the most important mechanisms involved in the regulation of staphylococcal biofilm formation. Finally, we highlight promising strategies and technologies, including multitargeted or combinational therapies, to eradicate staphylococcal biofilms.
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Affiliation(s)
- Katrin Schilcher
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado, USA
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133
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Schilcher K, Horswill AR. Staphylococcal Biofilm Development: Structure, Regulation, and Treatment Strategies. Microbiol Mol Biol Rev 2020. [PMID: 32792334 DOI: 10.1128/mmbr.00026-19/asset/e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023] Open
Abstract
In many natural and clinical settings, bacteria are associated with some type of biotic or abiotic surface that enables them to form biofilms, a multicellular lifestyle with bacteria embedded in an extracellular matrix. Staphylococcus aureus and Staphylococcus epidermidis, the most frequent causes of biofilm-associated infections on indwelling medical devices, can switch between an existence as single free-floating cells and multicellular biofilms. During biofilm formation, cells first attach to a surface and then multiply to form microcolonies. They subsequently produce the extracellular matrix, a hallmark of biofilm formation, which consists of polysaccharides, proteins, and extracellular DNA. After biofilm maturation into three-dimensional structures, the biofilm community undergoes a disassembly process that leads to the dissemination of staphylococcal cells. As biofilms are dynamic and complex biological systems, staphylococci have evolved a vast network of regulatory mechanisms to modify and fine-tune biofilm development upon changes in environmental conditions. Thus, biofilm formation is used as a strategy for survival and persistence in the human host and can serve as a reservoir for spreading to new infection sites. Moreover, staphylococcal biofilms provide enhanced resilience toward antibiotics and the immune response and impose remarkable therapeutic challenges in clinics worldwide. This review provides an overview and an updated perspective on staphylococcal biofilms, describing the characteristic features of biofilm formation, the structural and functional properties of the biofilm matrix, and the most important mechanisms involved in the regulation of staphylococcal biofilm formation. Finally, we highlight promising strategies and technologies, including multitargeted or combinational therapies, to eradicate staphylococcal biofilms.
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Affiliation(s)
- Katrin Schilcher
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Veterans Affairs Eastern Colorado Health Care System, Denver, Colorado, USA
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134
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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: 33] [Impact Index Per Article: 6.6] [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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135
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Hu D, Zou L, Gao Y, Jin Q, Ji J. Emerging nanobiomaterials against bacterial infections in postantibiotic era. VIEW 2020. [DOI: 10.1002/viw.20200014] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Dengfeng Hu
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization of Ministry of Education Department of Polymer Science and Engineering Zhejiang University Hangzhou China
| | - Lingyun Zou
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization of Ministry of Education Department of Polymer Science and Engineering Zhejiang University Hangzhou China
| | - Yifan Gao
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization of Ministry of Education Department of Polymer Science and Engineering Zhejiang University Hangzhou China
| | - Qiao Jin
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization of Ministry of Education Department of Polymer Science and Engineering Zhejiang University Hangzhou China
| | - Jian Ji
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization of Ministry of Education Department of Polymer Science and Engineering Zhejiang University Hangzhou China
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136
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Gaussia Luciferase as a Reporter for Quorum Sensing in Staphylococcus aureus. SENSORS 2020; 20:s20154305. [PMID: 32752273 PMCID: PMC7435925 DOI: 10.3390/s20154305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/23/2020] [Accepted: 07/30/2020] [Indexed: 11/16/2022]
Abstract
Gaussia luciferase (GLuc) is a secreted protein with significant potential for use as a reporter of gene expression in bacterial pathogenicity studies. To date there are relatively few examples of its use in bacteriology. In this study we show that GLuc can be functionally expressed in the human pathogen Staphylococcus aureus and furthermore show that it can be used as a biosensor for the agr quorum sensing (QS) system which employs autoinducing peptides to control virulence. GLuc was linked to the P3 promoter of the S. aureusagr operon. Biosensor strains were validated by evaluation of chemical agent-mediated activation and inhibition of agr. Use of GLuc enabled quantitative assessment of agr activity. This demonstrates the utility of Gaussia luciferase for in vitro monitoring of agr activation and inhibition.
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137
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Vasudevan S, Durai RD, Chellappan DR, Narayanan VHB, Prabu PC, Solomon AP. A polymer-based anti-quorum catheter coating to challenge MDR Staphylococcus aureus: in vivo and in vitro approaches. J Antimicrob Chemother 2020; 74:1618-1626. [PMID: 30863862 DOI: 10.1093/jac/dkz094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 02/05/2019] [Accepted: 02/14/2019] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND MDR Staphylococcus aureus is a major aetiological agent of catheter-associated infections. A quorum sensing targeted drug development approach proves to be an effective alternative strategy to combat such infections. METHODS Intravenous catheters were coated with polymethacrylate copolymers loaded with the antivirulent compound 2-[(methylamino)methyl]phenol (2MAMP). The in vitro drug release profile and kinetics were established. The anti-biofilm effect of the coated catheters was tested against clinical isolates of MDR S. aureus. The in vivo studies were carried out using adult male Wistar rats by implanting coated catheters in subcutaneous pockets. Histopathological analysis was done to understand the immunological reactions induced by 2MAMP. RESULTS A uniform catheter coating of thickness 0.1 mm was achieved with linear sustained release of 2MAMP for 6 h. The coating formulation was cytocompatible. The in vitro and in vivo anti-adherence studies showed reduced bacterial accumulation in coated catheters after 48 h. The histopathological results confirmed that the coated catheter did not bring about any adverse inflammatory response. CONCLUSIONS The developed anti-quorum-coated catheter that is non-toxic and biocompatible has the potential to be used in other medical devices, thereby preventing catheter-associated infections.
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Affiliation(s)
- Sahana Vasudevan
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, India
| | - Ramya Devi Durai
- Department of Pharmacy, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, India
| | | | - Vedha Hari B Narayanan
- Department of Pharmacy, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, India
| | - P C Prabu
- Department of Veterinary Pathology, Madras Veterinary College, Chennai, India
| | - Adline Princy Solomon
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, India
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138
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Possible drugs for the treatment of bacterial infections in the future: anti-virulence drugs. J Antibiot (Tokyo) 2020; 74:24-41. [PMID: 32647212 DOI: 10.1038/s41429-020-0344-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/26/2020] [Accepted: 05/29/2020] [Indexed: 12/19/2022]
Abstract
Antibiotic resistance is a global threat that should be urgently resolved. Finding a new antibiotic is one way, whereas the repression of the dissemination of virulent pathogenic bacteria is another. From this point of view, this paper summarizes first the mechanisms of conjugation and transformation, two important processes of horizontal gene transfer, and then discusses the approaches for disarming virulent pathogenic bacteria, that is, virulence factor inhibitors. In contrast to antibiotics, anti-virulence drugs do not impose a high selective pressure on a bacterial population, and repress the dissemination of antibiotic resistance and virulence genes. Disarmed virulence factors make virulent pathogens avirulent bacteria or pathobionts, so that we human will be able to coexist with these disarmed bacteria peacefully.
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139
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El-Mowafy M, Elgaml A, Shaaban M. New Approaches for Competing Microbial Resistance and Virulence. Microorganisms 2020. [DOI: 10.5772/intechopen.90388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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140
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Williams MR, Costa SK, Zaramela LS, Khalil S, Todd DA, Winter HL, Sanford JA, O'Neill AM, Liggins MC, Nakatsuji T, Cech NB, Cheung AL, Zengler K, Horswill AR, Gallo RL. Quorum sensing between bacterial species on the skin protects against epidermal injury in atopic dermatitis. Sci Transl Med 2020; 11:11/490/eaat8329. [PMID: 31043573 DOI: 10.1126/scitranslmed.aat8329] [Citation(s) in RCA: 177] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 11/12/2018] [Accepted: 04/11/2019] [Indexed: 12/15/2022]
Abstract
Colonization of the skin by Staphylococcus aureus is associated with exacerbation of atopic dermatitis (AD), but any direct mechanism through which dysbiosis of the skin microbiome may influence the development of AD is unknown. Here, we show that proteases and phenol-soluble modulin α (PSMα) secreted by S. aureus lead to endogenous epidermal proteolysis and skin barrier damage that promoted inflammation in mice. We further show that clinical isolates of different coagulase-negative staphylococci (CoNS) species residing on normal skin produced autoinducing peptides that inhibited the S. aureus agr system, in turn decreasing PSMα expression. These autoinducing peptides from skin microbiome CoNS species potently suppressed PSMα expression in S. aureus isolates from subjects with AD without inhibiting S. aureus growth. Metagenomic analysis of the AD skin microbiome revealed that the increase in the relative abundance of S. aureus in patients with active AD correlated with a lower CoNS autoinducing peptides to S. aureus ratio, thus overcoming the peptides' capacity to inhibit the S. aureus agr system. Characterization of a S. hominis clinical isolate identified an autoinducing peptide (SYNVCGGYF) as a highly potent inhibitor of S. aureus agr activity, capable of preventing S. aureus-mediated epithelial damage and inflammation on murine skin. Together, these findings show how members of the normal human skin microbiome can contribute to epithelial barrier homeostasis by using quorum sensing to inhibit S. aureus toxin production.
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Affiliation(s)
- Michael R Williams
- Department of Dermatology, University of California, San Diego, San Diego, CA 92093, USA
| | - Stephen K Costa
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Livia S Zaramela
- Department of Pediatrics, University of California, San Diego, San Diego, CA 92093, USA
| | - Shadi Khalil
- Department of Dermatology, University of California, San Diego, San Diego, CA 92093, USA
| | - Daniel A Todd
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402-6170, USA
| | - Heather L Winter
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402-6170, USA
| | - James A Sanford
- Department of Dermatology, University of California, San Diego, San Diego, CA 92093, USA
| | - Alan M O'Neill
- Department of Dermatology, University of California, San Diego, San Diego, CA 92093, USA
| | - Marc C Liggins
- Department of Dermatology, University of California, San Diego, San Diego, CA 92093, USA
| | - Teruaki Nakatsuji
- Department of Dermatology, University of California, San Diego, San Diego, CA 92093, USA
| | - Nadja B Cech
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402-6170, USA
| | - Ambrose L Cheung
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Karsten Zengler
- Department of Pediatrics, University of California, San Diego, San Diego, CA 92093, USA.,Center for Microbiome Innovation, University of California, San Diego, San Diego, CA 92093, USA.,Department of Bioengineering, University of California, San Diego, San Diego, CA 92093, USA
| | - Alexander R Horswill
- Department of Veterans Affairs Denver Health Care System, Denver, CO 80045, USA.,Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Richard L Gallo
- Department of Dermatology, University of California, San Diego, San Diego, CA 92093, USA. .,Center for Microbiome Innovation, University of California, San Diego, San Diego, CA 92093, USA
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141
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Piewngam P, Chiou J, Chatterjee P, Otto M. Alternative approaches to treat bacterial infections: targeting quorum-sensing. Expert Rev Anti Infect Ther 2020; 18:499-510. [PMID: 32243194 PMCID: PMC11032741 DOI: 10.1080/14787210.2020.1750951] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 03/31/2020] [Indexed: 12/22/2022]
Abstract
Introduction: The emergence of multi- and pan-drug-resistant bacteria represents a global crisis that calls for the development of alternative anti-infective strategies. These comprise anti-virulence approaches, which target pathogenicity without exerting a bacteriostatic or bactericidal effect and are claimed to reduce the development of resistance. Because in many pathogens, quorum-sensing (QS) systems control the expression of virulence factors, interference with QS, or quorum-quenching, is often proposed as a strategy with a broad anti-virulence effect.Areas covered: We discuss the role and regulatory targets of QS control in selected Gram-positive and Gram-negative bacteria, focusing on those with clinical importance and QS control of virulence. We present the components of QS systems that form possible targets for the development of anti-virulence drugs and discuss recent research on quorum-quenching approaches to control bacterial infection.Expert opinion: While there has been extensive research on QS systems and quorum-quenching approaches, there is a paucity of in-vivo research using adequate animal models to substantiate applicability. In-vivo research on QS blockers needs to be intensified and optimized to use clinically relevant setups, in order to underscore that such drugs can be used effectively to overcome problems associated with the treatment of severe infections by antibiotic-resistant pathogens.
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Affiliation(s)
- Pipat Piewngam
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, Maryland 20814, USA
| | - Janice Chiou
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, Maryland 20814, USA
| | - Priyanka Chatterjee
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, Maryland 20814, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, Maryland 20814, USA
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142
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Novel Peptide from Commensal Staphylococcus simulans Blocks Methicillin-Resistant Staphylococcus aureus Quorum Sensing and Protects Host Skin from Damage. Antimicrob Agents Chemother 2020; 64:AAC.00172-20. [PMID: 32253213 DOI: 10.1128/aac.00172-20] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 03/29/2020] [Indexed: 12/21/2022] Open
Abstract
Recent studies highlight the abundance of commensal coagulase-negative staphylococci (CoNS) on healthy skin. Evidence suggests that CoNS actively shape the skin immunological and microbial milieu to resist colonization or infection by opportunistic pathogens, including methicillin-resistant Staphylococcus aureus (MRSA), in a variety of mechanisms collectively termed colonization resistance. One potential colonization resistance mechanism is the application of quorum sensing, also called the accessory gene regulator (agr) system, which is ubiquitous among staphylococci. Common and rare CoNS make autoinducing peptides (AIPs) that function as MRSA agr inhibitors, protecting the host from invasive infection. In a screen of CoNS spent media, we found that Staphylococcus simulans, a rare human skin colonizer and frequent livestock colonizer, released potent inhibitors of all classes of MRSA agr signaling. We identified three S. simulans agr classes and have shown intraspecies cross talk between noncognate S. simulans agr types for the first time. The S. simulans AIP-I structure was confirmed, and the novel AIP-II and AIP-III structures were solved via mass spectrometry. Synthetic S. simulans AIPs inhibited MRSA agr signaling with nanomolar potency. S. simulans in competition with MRSA reduced dermonecrotic and epicutaneous skin injury in murine models. The addition of synthetic AIP-I also effectively reduced MRSA dermonecrosis and epicutaneous skin injury in murine models. These results demonstrate potent anti-MRSA quorum sensing inhibition by a rare human skin commensal and suggest that cross talk between CoNS and MRSA may be important in maintaining healthy skin homeostasis and preventing MRSA skin damage during colonization or acute infection.
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143
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Tsai CN, MacNair CR, Cao MPT, Perry JN, Magolan J, Brown ED, Coombes BK. Targeting Two-Component Systems Uncovers a Small-Molecule Inhibitor of Salmonella Virulence. Cell Chem Biol 2020; 27:793-805.e7. [PMID: 32413287 DOI: 10.1016/j.chembiol.2020.04.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/27/2020] [Accepted: 04/06/2020] [Indexed: 12/27/2022]
Abstract
Salmonella serovars are leading causes of gastrointestinal disease and have become increasingly resistant to fluoroquinolone and cephalosporin antibiotics. Overcoming this healthcare crisis requires new approaches in antibiotic discovery and the identification of unique bacterial targets. In this work, we describe a chemical genomics approach to identify inhibitors of Salmonella virulence. From a cell-based, promoter reporter screen of ∼50,000 small molecules, we identified dephostatin as a non-antibiotic compound that inhibits intracellular virulence factors and polymyxin resistance genes. Dephostatin disrupts signaling through both the SsrA-SsrB and PmrB-PmrA two-component regulatory systems and restores sensitivity to the last-resort antibiotic, colistin. Cell-based experiments and mouse models of infection demonstrate that dephostatin attenuates Salmonella virulence in vitro and in vivo, suggesting that perturbing regulatory networks is a promising strategy for the development of anti-infectives.
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Affiliation(s)
- Caressa N Tsai
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada; Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Craig R MacNair
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada; Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - My P T Cao
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8S 4L8, Canada; Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Jordyn N Perry
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada; Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Jakob Magolan
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada; Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8S 4L8, Canada; Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Eric D Brown
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada; Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Brian K Coombes
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada; Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8S 4L8, Canada.
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144
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Gordon CP. Synthetic strategies to access staphylococcus auto-inducing peptides as quorum sensing modulators. Org Biomol Chem 2020; 18:379-390. [PMID: 31844862 DOI: 10.1039/c9ob02038a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The accessory gene regulator (agr) quorum-sensing system is arguably the most important regulator of staphylococcus virulence and has been the focus of tremendous interest in the development of effective therapies for pathogenic bacterial infections. With regards to chemotherapeutic based strategies, the significant proportion of currently reported agr-system modulating molecules are mimics of the native ArgC substrate, which is a thioester-based macrocyclic peptide know as the auto-inducing peptide. Over the past two decades, more than two-hundred synthetic analogues have been reported. This review traces the development of the synthetic strategies employed to synthesise these analogues with a particular focus on macrocyclisation. At present these synthetic approaches can be clustered into five broad categories (1) solution-phase cyclisation, (2) immobilised carbodiimide assisted cyclisation, (3) concomitant on-resin cleavage and macrocyclisation, (4) Boc-compatible chemoselective thioesterification, and (5) Fmoc-compatible chemoselective thioesterification. The advantages and limitation provided by each of the approaches are compared and contrasted with a view towards potential reaction scale-up.
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Affiliation(s)
- Christopher P Gordon
- School of Science and Health, Western Sydney University, Locked Bag 1797, Penrith South DC, NSW 2751, Australia.
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145
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Manson DE, O’Reilly MC, Nyffeler KE, Blackwell HE. Design, Synthesis, and Biochemical Characterization of Non-Native Antagonists of the Pseudomonas aeruginosa Quorum Sensing Receptor LasR with Nanomolar IC 50 Values. ACS Infect Dis 2020; 6:649-661. [PMID: 32037806 DOI: 10.1021/acsinfecdis.9b00518] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Quorum sensing (QS), a bacterial cell-to-cell communication system mediated by small molecules and peptides, has received significant interest as a potential target to block infection. The common pathogen Pseudomonas aeruginosa uses QS to regulate many of its virulence phenotypes at high cell densities, and the LasR QS receptor plays a critical role in this process. Small molecule tools that inhibit LasR activity would serve to illuminate its role in P. aeruginosa virulence, but we currently lack highly potent and selective LasR antagonists, despite considerable research in this area. V-06-018, an abiotic small molecule discovered in a high-throughput screen, represents one of the most potent known LasR antagonists but has seen little study since its initial report. Herein, we report a systematic study of the structure-activity relationships (SARs) that govern LasR antagonism by V-06-018. We synthesized a focused library of V-06-018 derivatives and evaluated the library for bioactivity using a variety of cell-based LasR reporter systems. The SAR trends revealed by these experiments allowed us to design probes with 10-fold greater potency than that of V-06-018 and 100-fold greater potency than other commonly used N-acyl-l-homoserine lactone (AHL)-based LasR antagonists, along with high selectivities for LasR. Biochemical experiments to probe the mechanism of antagonism by V-06-018 and its analogues support these compounds interacting with the native ligand-binding site in LasR and, at least in part, stabilizing an inactive form of the protein. The compounds described herein are the most potent and efficacious antagonists of LasR known and represent robust probes both for characterizing the mechanisms of LuxR-type QS and for chemical biology research in general in the growing QS field.
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Affiliation(s)
- Daniel E. Manson
- Department of Chemistry, University of Wisconsin−Madison, 110 University Ave., Madison, Wisconsin 53706 United States
| | - Matthew C. O’Reilly
- Department of Chemistry, University of Wisconsin−Madison, 110 University Ave., Madison, Wisconsin 53706 United States
| | - Kayleigh E. Nyffeler
- Department of Chemistry, University of Wisconsin−Madison, 110 University Ave., Madison, Wisconsin 53706 United States
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin−Madison, 110 University Ave., Madison, Wisconsin 53706 United States
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146
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Tham EH, Koh E, Common JEA, Hwang IY. Biotherapeutic Approaches in Atopic Dermatitis. Biotechnol J 2020; 15:e1900322. [PMID: 32176834 DOI: 10.1002/biot.201900322] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 02/24/2020] [Indexed: 12/15/2022]
Abstract
The skin microbiome plays a central role in inflammatory skin disorders such as atopic dermatitis (AD). In AD patients, an imbalance between pathogenic Staphylococcus aureus (S. aureus) and resident skin symbionts creates a state of dysbiosis which induces immune dysregulation and impairs skin barrier function. There are now exciting new prospects for microbiome-based interventions for AD prevention. In the hopes of achieving sustained control and management of disease in AD patients, current emerging biotherapeutic strategies aim to harness the skin microbiome associated with health by restoring a more diverse symbiotic skin microbiome, while selectively removing pathogenic S. aureus. Examples of such strategies are demonstrated in skin microbiome transplants, phage-derived anti-S. aureus endolysins, monoclonal antibodies, and quorum sensing (QS) inhibitors. However, further understanding of the skin microbiome and its role in AD pathogenesis is still needed to understand how these biotherapeutics alter the dynamics of the microbiome community; to optimize patient selection, drug delivery, and treatment duration; overcome rapid recolonization upon treatment cessation; and improve efficacy to allow these therapeutic options to eventually reach routine clinical practice.
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Affiliation(s)
- Elizabeth Huiwen Tham
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Singapore.,Khoo Teck Puat-National University Children's Medical Institute, National University Hospital, National University Health System, Singapore, 119074, Singapore
| | - Elvin Koh
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Singapore.,NUS Synthetic Biology for Clinical and Technological Innovation, National University of Singapore, Singapore, 119228, Singapore
| | - John E A Common
- Skin Research Institute of Singapore, A*STAR, Singapore, 308232, Singapore
| | - In Young Hwang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Singapore.,NUS Synthetic Biology for Clinical and Technological Innovation, National University of Singapore, Singapore, 119228, Singapore
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147
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Marchetti M, De Bei O, Bettati S, Campanini B, Kovachka S, Gianquinto E, Spyrakis F, Ronda L. Iron Metabolism at the Interface between Host and Pathogen: From Nutritional Immunity to Antibacterial Development. Int J Mol Sci 2020; 21:E2145. [PMID: 32245010 PMCID: PMC7139808 DOI: 10.3390/ijms21062145] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 02/08/2023] Open
Abstract
Nutritional immunity is a form of innate immunity widespread in both vertebrates and invertebrates. The term refers to a rich repertoire of mechanisms set up by the host to inhibit bacterial proliferation by sequestering trace minerals (mainly iron, but also zinc and manganese). This strategy, selected by evolution, represents an effective front-line defense against pathogens and has thus inspired the exploitation of iron restriction in the development of innovative antimicrobials or enhancers of antimicrobial therapy. This review focuses on the mechanisms of nutritional immunity, the strategies adopted by opportunistic human pathogen Staphylococcus aureus to circumvent it, and the impact of deletion mutants on the fitness, infectivity, and persistence inside the host. This information finally converges in an overview of the current development of inhibitors targeting the different stages of iron uptake, an as-yet unexploited target in the field of antistaphylococcal drug discovery.
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Affiliation(s)
- Marialaura Marchetti
- Interdepartmental Center Biopharmanet-TEC, University of Parma, 43124 Parma, Italy; (M.M.); (S.B.)
| | - Omar De Bei
- Department of Food and Drug, University of Parma, 43124 Parma, Italy; (O.D.B.); (B.C.)
| | - Stefano Bettati
- Interdepartmental Center Biopharmanet-TEC, University of Parma, 43124 Parma, Italy; (M.M.); (S.B.)
- Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy
- Institute of Biophysics, National Research Council, 56124 Pisa, Italy
- National Institute of Biostructures and Biosystems, 00136 Rome, Italy
| | - Barbara Campanini
- Department of Food and Drug, University of Parma, 43124 Parma, Italy; (O.D.B.); (B.C.)
| | - Sandra Kovachka
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (S.K.); (E.G.); (F.S.)
| | - Eleonora Gianquinto
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (S.K.); (E.G.); (F.S.)
| | - Francesca Spyrakis
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (S.K.); (E.G.); (F.S.)
| | - Luca Ronda
- Interdepartmental Center Biopharmanet-TEC, University of Parma, 43124 Parma, Italy; (M.M.); (S.B.)
- Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy
- Institute of Biophysics, National Research Council, 56124 Pisa, Italy
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148
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Small Molecules Produced by Commensal Staphylococcus epidermidis Disrupt Formation of Biofilms by Staphylococcus aureus. Appl Environ Microbiol 2020; 86:AEM.02539-19. [PMID: 31862721 DOI: 10.1128/aem.02539-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 12/16/2019] [Indexed: 11/20/2022] Open
Abstract
The microbiota influences host health through several mechanisms, including protecting it from pathogen colonization. Staphylococcus epidermidis is one of the most frequently found species in the skin microbiota, and its presence can limit the development of pathogens such as Staphylococcus aureus S. aureus causes diverse types of infections ranging from skin abscesses to bloodstream infections. Given the increasing prevalence of S. aureus drug-resistant strains, it is imperative to search for new strategies for treatment and prevention. Thus, we investigated the activity of molecules produced by a commensal S. epidermidis isolate against S. aureus biofilms. We showed that molecules present in S. epidermidis cell-free conditioned media (CFCM) caused a significant reduction in biofilm formation in most S. aureus clinical isolates, including all 4 agr types and agr-defective strains, without any impact on growth. S. epidermidis molecules also disrupted established S. aureus biofilms and reduced the antibiotic concentration required to eliminate them. Preliminary characterization of the active compound showed that its activity is resistant to heat, protease inhibitors, trypsin, proteinase K, and sodium periodate treatments, suggesting that it is not proteinaceous. RNA sequencing revealed that S. epidermidis-secreted molecules modulate the expression of hundreds of S. aureus genes, some of which are associated with biofilm production. Biofilm formation is one of the main virulence factors of S. aureus and has been associated with chronic infections and antimicrobial resistance. Therefore, molecules that can counteract this virulence factor may be promising alternatives as novel therapeutic agents to control S. aureus infections.IMPORTANCE S. aureus is a leading agent of infections worldwide, and its main virulence characteristic is the ability to produce biofilms on surfaces such as medical devices. Biofilms are known to confer increased resistance to antimicrobials and to the host immune responses, requiring aggressive antibiotic treatment and removal of the infected surface. Here, we investigated a new source of antibiofilm compounds, the skin microbiome. Specifically, we found that a commensal strain of S. epidermidis produces molecules with antibiofilm activity, leading to a significant decrease of S. aureus biofilm formation and to a reduction of previously established biofilms. The molecules potentiated the activity of antibiotics and affected the expression of hundreds of S. aureus genes, including those associated with biofilm formation. Our research highlights the search for compounds that can aid us in the fight against S. aureus infections.
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149
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Paluch E, Rewak-Soroczyńska J, Jędrusik I, Mazurkiewicz E, Jermakow K. Prevention of biofilm formation by quorum quenching. Appl Microbiol Biotechnol 2020; 104:1871-1881. [PMID: 31927762 PMCID: PMC7007913 DOI: 10.1007/s00253-020-10349-w] [Citation(s) in RCA: 188] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 12/26/2019] [Accepted: 01/03/2020] [Indexed: 02/08/2023]
Abstract
Quorum sensing (QS) is a mechanism that enables microbial communication. It is based on the constant secretion of signaling molecules to the environment. The main role of QS is the regulation of vital processes in the cell such as virulence factor production or biofilm formation. Due to still growing bacterial resistance to antibiotics that have been overused, it is necessary to search for alternative antimicrobial therapies. One of them is quorum quenching (QQ) that disrupts microbial communication. QQ-driving molecules can decrease or even completely inhibit the production of virulence factors (including biofilm formation). There are few QQ strategies that comprise the use of the structural analogues of QS receptor autoinductors (AI). They may be found in nature or be designed and synthesized via chemical engineering. Many of the characterized QQ molecules are enzymes with the ability to degrade signaling molecules. They can also impede cellular signaling cascades. There are different techniques used for testing QS/QQ, including chromatography-mass spectroscopy, bioluminescence, chemiluminescence, fluorescence, electrochemistry, and colorimetry. They all enable qualitative and quantitative measurements of QS/QQ molecules. This article gathers the information about the mechanisms of QS and QQ, and their effect on microbial biofilm formation. Basic methods used to study QS/QQ, as well as the medical and biotechnological applications of QQ, are also described. Basis research methods are also described as well as medical and biotechnological application.
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Affiliation(s)
- E Paluch
- Department of Microbiology, Faculty of Medicine, Wroclaw Medical University, Tytusa Chałubińskiego 4, 50-376, Wrocław, Poland.
| | - J Rewak-Soroczyńska
- Institute of Low Temperature and Structure Research, Polish Academy of Science, Okólna 2, 50-422, Wroclaw, Poland
| | - I Jędrusik
- Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63/77, 51-148, Wrocław, Poland
| | - E Mazurkiewicz
- Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63/77, 51-148, Wrocław, Poland
| | - K Jermakow
- Department of Microbiology, Faculty of Medicine, Wroclaw Medical University, Tytusa Chałubińskiego 4, 50-376, Wrocław, Poland
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150
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Vasquez JK, West KHJ, Yang T, Polaske TJ, Cornilescu G, Tonelli M, Blackwell HE. Conformational Switch to a β-Turn in a Staphylococcal Quorum Sensing Signal Peptide Causes a Dramatic Increase in Potency. J Am Chem Soc 2020; 142:750-761. [PMID: 31859506 DOI: 10.1021/jacs.9b05513] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report the solution-phase structures of native signal peptides and related analogs capable of either strongly agonizing or antagonizing the AgrC quorum sensing (QS) receptor in the emerging pathogen Staphylococcus epidermidis. Chronic S. epidermidis infections are often recalcitrant to traditional therapies due to antibiotic resistance and formation of robust biofilms. The accessory gene regulator (agr) QS system plays an important role in biofilm formation in this opportunistic pathogen, and the binding of an autoinducing peptide (AIP) signal to its cognate transmembrane receptor (AgrC) is responsible for controlling agr. Small molecules or peptides capable of modulating this binding event are of significant interest as probes to investigate both the agr system and QS as a potential antivirulence target. We used NMR spectroscopy to characterize the structures of the three native S. epidermidis AIP signals and five non-native analogs with distinct activity profiles in the AgrC-I receptor from S. epidermidis. These studies revealed a suite of structural motifs critical for ligand activity. Interestingly, a unique β-turn was present in the macrocycles of the two most potent AgrC-I modulators, in both an agonist and an antagonist, which was distinct from the macrocycle conformation in the less-potent AgrC-I modulators and in the native AIP-I itself. This previously unknown β-turn provides a structural rationale for these ligands' respective biological activity profiles. Development of analogs to reinforce the β-turn resulted in our first antagonist with subnanomolar potency in AgrC-I, while analogs designed to contain a disrupted β-turn were dramatically less potent relative to their parent compounds. Collectively, these studies provide new insights into the AIP:AgrC interactions crucial for QS activation in S. epidermidis and advance the understanding of QS at the molecular level.
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Affiliation(s)
- Joseph K Vasquez
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Korbin H J West
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Tian Yang
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Thomas J Polaske
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Gabriel Cornilescu
- National Magnetic Resonance Facility at Madison , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Marco Tonelli
- National Magnetic Resonance Facility at Madison , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Helen E Blackwell
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
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