1
|
Thakkar N, Gajera G, Mehta D, Kothari V. Silversol ® (a Colloidal Nanosilver Formulation) Inhibits Growth of Antibiotic-Resistant Staphylococcus aureus by Disrupting Its Physiology in Multiple Ways. Pharmaceutics 2024; 16:726. [PMID: 38931848 PMCID: PMC11206351 DOI: 10.3390/pharmaceutics16060726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/28/2024] Open
Abstract
Antibiotic-resistant strains of Staphylococcus aureus are being viewed as a serious threat by various public health agencies. Identifying novel targets in this important pathogen is crucial to the development of new effective antibacterial formulations. We investigated the antibacterial effect of a colloidal nanosilver formulation, Silversol®, against an antibiotic-resistant strain of S. aureus using appropriate in vitro assays. Moreover, we deciphered the molecular mechanisms underlying this formulation's anti-S. aureus activity using whole transcriptome analysis. Lower concentrations of the test formulation exerted a bacteriostatic effect against this pathogen, and higher concentrations exerted a bactericidal effect. Silversol® at sub-lethal concentration was found to disturb multiple physiological traits of S. aureus such as growth, antibiotic susceptibility, membrane permeability, efflux, protein synthesis and export, biofilm and exopolysaccharide production, etc. Transcriptome data revealed that the genes coding for transcriptional regulators, efflux machinery, transferases, β-lactam resistance, oxidoreductases, metal homeostasis, virulence factors, and arginine biosynthesis are expressed differently under the influence of the test formulation. Genes (argG and argH) involved in arginine biosynthesis emerged among the major targets of Silversol®'s antibacterial activity against S. aureus.
Collapse
Affiliation(s)
- Nidhi Thakkar
- Institute of Science, Nirma University, Ahmedabad 382481, India; (N.T.); (G.G.)
| | - Gemini Gajera
- Institute of Science, Nirma University, Ahmedabad 382481, India; (N.T.); (G.G.)
| | - Dilip Mehta
- Viridis BioPharma Pvt. Ltd., Mumbai 400043, India;
| | - Vijay Kothari
- Institute of Science, Nirma University, Ahmedabad 382481, India; (N.T.); (G.G.)
| |
Collapse
|
2
|
Franco AR, Sadones O, Romerio A, Artusa V, Shaik MM, Pasco ST, Italia A, D'Amato S, Anguita J, Huebner J, Romero-Saavedra F, Peri F. Novel TLR4-Activating Vaccine Adjuvant Enhances the Production of Enterococcus faecium-binding Antibodies. J Med Chem 2024; 67:5603-5616. [PMID: 38513080 DOI: 10.1021/acs.jmedchem.3c02215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
Vaccines are one of the greatest achievements of modern medicine. Due to their safer profile, the latest investigations usually focus on subunit vaccines. However, the active component often needs to be coupled with an adjuvant to be effective and properly trigger an immune response. We are developing a new synthetic monosaccharide-based TLR4 agonist, such as glucosamine-derived compounds FP18 and FP20, as a potential vaccine adjuvant. In this study, we present a new FP20 derivative, FP20Hmp, with a hydroxylated ester linked to the glucosamine core. We show that the modification introduced improves the activity of the adjuvant and its solubility. This study presents the synthesis of FP20Hmp, its in vitro characterization, and in vivo activity while coupled with the ovalbumin antigen or in formulation with an enterococcal antigen. We show that FP20Hmp enables increased production of antigen-specific antibodies that bind to the whole bacterium.
Collapse
Affiliation(s)
- Ana Rita Franco
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, Milano 20126, Italy
| | - Océane Sadones
- Division of Pediatric Infectious disease, Hauner Children's Hospital, LMU, Munich 80337, Germany
| | - Alessio Romerio
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, Milano 20126, Italy
| | - Valentina Artusa
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, Milano 20126, Italy
| | - Mohammed Monsoor Shaik
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, Milano 20126, Italy
| | - Samuel T Pasco
- Inflammation and Macrophage Plasticity Laboratory, CIC bioGUNE-Basque Research and Technology Alliance (BRTA), Parque Tecnológico de Bizkaia, Derio 48160, Spain
| | - Alice Italia
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, Milano 20126, Italy
| | - Simona D'Amato
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, Milano 20126, Italy
| | - Juan Anguita
- Inflammation and Macrophage Plasticity Laboratory, CIC bioGUNE-Basque Research and Technology Alliance (BRTA), Parque Tecnológico de Bizkaia, Derio 48160, Spain
- Ikerbasque, Basque Foundation for Science, Plaza Euskadi 5, Bilbao 48009, Spain
| | - Johannes Huebner
- Division of Pediatric Infectious disease, Hauner Children's Hospital, LMU, Munich 80337, Germany
| | - Felipe Romero-Saavedra
- Division of Pediatric Infectious disease, Hauner Children's Hospital, LMU, Munich 80337, Germany
| | - Francesco Peri
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, Milano 20126, Italy
| |
Collapse
|
3
|
Kohler V, Goessweiner-Mohr N, Aufschnaiter A, Fercher C, Probst I, Pavkov-Keller T, Hunger K, Wolinski H, Büttner S, Grohmann E, Keller W. TraN: A novel repressor of an Enterococcus conjugative type IV secretion system. Nucleic Acids Res 2019; 46:9201-9219. [PMID: 30060171 PMCID: PMC6158623 DOI: 10.1093/nar/gky671] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/18/2018] [Indexed: 11/19/2022] Open
Abstract
The dissemination of multi-resistant bacteria represents an enormous burden on modern healthcare. Plasmid-borne conjugative transfer is the most prevalent mechanism, requiring a type IV secretion system that enables bacteria to spread beneficial traits, such as resistance to last-line antibiotics, among different genera. Inc18 plasmids, like the Gram-positive broad host-range plasmid pIP501, are substantially involved in propagation of vancomycin resistance from Enterococci to methicillin-resistant strains of Staphylococcus aureus. Here, we identified the small cytosolic protein TraN as a repressor of the pIP501-encoded conjugative transfer system, since deletion of traN resulted in upregulation of transfer factors, leading to highly enhanced conjugative transfer. Furthermore, we report the complex structure of TraN with DNA and define the exact sequence of its binding motif. Targeting this protein–DNA interaction might represent a novel therapeutic approach against the spreading of antibiotic resistances.
Collapse
Affiliation(s)
- Verena Kohler
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Nikolaus Goessweiner-Mohr
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria.,Institute of Biophysics, Johannes Kepler University, Linz 4020, Austria
| | | | - Christian Fercher
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Ines Probst
- Division of Infectious Diseases, University Medical Center Freiburg, Freiburg 79106, Germany
| | - Tea Pavkov-Keller
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Kristin Hunger
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Sabrina Büttner
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria.,Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm 10691, Sweden
| | - Elisabeth Grohmann
- Division of Infectious Diseases, University Medical Center Freiburg, Freiburg 79106, Germany.,Life Sciences and Technology, Beuth University of Applied Sciences, Berlin 13353, Germany
| | - Walter Keller
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria.,BioTechMed-Graz, Austria
| |
Collapse
|
4
|
Boudaher E, Shaffer CL. Inhibiting bacterial secretion systems in the fight against antibiotic resistance. MEDCHEMCOMM 2019; 10:682-692. [PMID: 31741728 DOI: 10.1039/c9md00076c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 04/22/2019] [Indexed: 12/11/2022]
Abstract
Antimicrobial resistance is a mounting global health crisis that threatens a resurgence of life-threatening bacterial infections. Despite intensive drug discovery efforts, the rate of antimicrobial resistance outpaces the discovery of new antibiotic agents. One of the major mechanisms driving the rapid propagation of antibiotic resistance is bacterial conjugation mediated by the versatile type IV secretion system (T4SS). The search for therapeutic compounds that prevent the spread of antibiotic resistance via T4SS-dependent mechanisms has identified several promising molecular scaffolds that disrupt resistance determinant dissemination. In this brief review, we highlight the progress and potential of conjugation inhibitors and anti-virulence compounds that target diverse T4SS machineries. These studies provide a solid foundation for the future development of potent, dual-purpose molecular scaffolds that can be used as biochemical tools to probe type IV secretion mechanisms and target bacterial conjugation in clinical settings to prevent the dissemination of antibiotic resistance throughout microbial populations.
Collapse
Affiliation(s)
- Elizabeth Boudaher
- University of Kentucky , Department of Veterinary Science , Gluck Equine Research Center , 1400 Nicholasville Road , Lexington , KY , USA . ; Tel: +1 (859) 218 1168
| | - Carrie L Shaffer
- University of Kentucky , Department of Veterinary Science , Gluck Equine Research Center , 1400 Nicholasville Road , Lexington , KY , USA . ; Tel: +1 (859) 218 1168.,University of Kentucky , Department of Microbiology, Immunology, and Molecular Genetics , 800 Rose Street , Lexington , KY , USA.,University of Kentucky , Department of Pharmaceutical Sciences , 789 South Limestone Street , Lexington , KY , USA
| |
Collapse
|
5
|
Sobisch LY, Rogowski KM, Fuchs J, Schmieder W, Vaishampayan A, Oles P, Novikova N, Grohmann E. Biofilm Forming Antibiotic Resistant Gram-Positive Pathogens Isolated From Surfaces on the International Space Station. Front Microbiol 2019; 10:543. [PMID: 30941112 PMCID: PMC6433718 DOI: 10.3389/fmicb.2019.00543] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 03/01/2019] [Indexed: 12/18/2022] Open
Abstract
The International Space Station (ISS) is a closed habitat in a uniquely extreme and hostile environment. Due to these special conditions, the human microflora can undergo unusual changes and may represent health risks for the crew. To address this problem, we investigated the antimicrobial activity of AGXX®, a novel surface coating consisting of micro-galvanic elements of silver and ruthenium along with examining the activity of a conventional silver coating. The antimicrobial materials were exposed on the ISS for 6, 12, and 19 months each at a place frequently visited by the crew. Bacteria that survived on the antimicrobial coatings [AGXX® and silver (Ag)] or the uncoated stainless steel carrier (V2A, control material) were recovered, phylogenetically affiliated and characterized in terms of antibiotic resistance (phenotype and genotype), plasmid content, biofilm formation capacity and antibiotic resistance transferability. On all three materials, surviving bacteria were dominated by Gram-positive bacteria and among those by Staphylococcus, Bacillus and Enterococcus spp. The novel antimicrobial surface coating proved to be highly effective. The conventional Ag coating showed only little antimicrobial activity. Microbial diversity increased with increasing exposure time on all three materials. The number of recovered bacteria decreased significantly from V2A to V2A-Ag to AGXX®. After 6 months exposure on the ISS no bacteria were recovered from AGXX®, after 12 months nine and after 19 months three isolates were obtained. Most Gram-positive pathogenic isolates were multidrug resistant (resistant to more than three antibiotics). Sulfamethoxazole, erythromycin and ampicillin resistance were most prevalent. An Enterococcus faecalis strain recovered from V2A steel after 12 months exposure exhibited the highest number of resistances (n = 9). The most prevalent resistance genes were ermC (erythromycin resistance) and tetK (tetracycline resistance). Average transfer frequency of erythromycin, tetracycline and gentamicin resistance from selected ISS isolates was 10−5 transconjugants/recipient. Most importantly, no serious human pathogens such as methicillin resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococci (VRE) were found on any surface. Thus, the infection risk for the crew is low, especially when antimicrobial surfaces such as AGXX® are applied to surfaces prone to microbial contamination.
Collapse
Affiliation(s)
- Lydia-Yasmin Sobisch
- Life Sciences and Technology, Microbiology, Beuth University of Applied Sciences, Berlin, Germany
| | - Katja Marie Rogowski
- Life Sciences and Technology, Microbiology, Beuth University of Applied Sciences, Berlin, Germany
| | - Jonathan Fuchs
- Institute of Biology, University Freiburg, Freiburg, Germany
| | | | - Ankita Vaishampayan
- Life Sciences and Technology, Microbiology, Beuth University of Applied Sciences, Berlin, Germany
| | - Patricia Oles
- Life Sciences and Technology, Microbiology, Beuth University of Applied Sciences, Berlin, Germany
| | | | - Elisabeth Grohmann
- Life Sciences and Technology, Microbiology, Beuth University of Applied Sciences, Berlin, Germany.,Institute of Biology, University Freiburg, Freiburg, Germany
| |
Collapse
|
6
|
Kohler V, Vaishampayan A, Grohmann E. Broad-host-range Inc18 plasmids: Occurrence, spread and transfer mechanisms. Plasmid 2018; 99:11-21. [PMID: 29932966 DOI: 10.1016/j.plasmid.2018.06.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/17/2018] [Accepted: 06/18/2018] [Indexed: 11/18/2022]
Abstract
Conjugative plasmid transfer is one of the major mechanisms responsible for the spread of antibiotic resistance and virulence genes. The incompatibility (Inc) 18 group of plasmids is a family of plasmids replicating by the theta-mechanism, whose members have been detected frequently in enterococci and streptococci. Inc18 plasmids encode a variety of antibiotic resistances, including resistance to vancomycin, chloramphenicol and the macrolide-lincosamide-streptogramine (MLS) group of antibiotics. These plasmids comprising insertions of Tn1546 were demonstrated to be responsible for the transfer of vancomycin resistance encoded by the vanA gene from vancomycin resistant enterococci (VRE) to methicillin resistant Staphylococcus aureus (MRSA). Thereby vancomycin resistant S. aureus (VRSA) were generated, which are serious multi-resistant pathogens challenging the health care system. Inc18 plasmids are widespread in the clinic and frequently have been detected in the environment, especially in domestic animals and wastewater. pIP501 is one of the best-characterized conjugative Inc18 plasmids. It was originally isolated from a clinical Streptococcus agalactiae strain and is, due to its small size and simplicity, a model to study conjugative plasmid transfer in Gram-positive bacteria. Here, we report on the occurrence and spread of Inc18-type plasmids in the clinic and in different environments as well as on the exchange of the plasmids among them. In addition, we discuss molecular details on the transfer mechanism of Inc18 plasmids and its regulation, as exemplified by the model plasmid pIP501. We finish with an outlook on promising approaches on how to reduce the emerging spread of antibiotic resistances.
Collapse
Affiliation(s)
- Verena Kohler
- Institute of Molecular Biosciences, University of Graz, A-8010 Graz, Austria
| | - Ankita Vaishampayan
- Life Sciences and Technology, Beuth University of Applied Sciences Berlin, D-13347 Berlin, Germany
| | - Elisabeth Grohmann
- Life Sciences and Technology, Beuth University of Applied Sciences Berlin, D-13347 Berlin, Germany.
| |
Collapse
|
7
|
Grohmann E, Christie PJ, Waksman G, Backert S. Type IV secretion in Gram-negative and Gram-positive bacteria. Mol Microbiol 2018; 107:455-471. [PMID: 29235173 PMCID: PMC5796862 DOI: 10.1111/mmi.13896] [Citation(s) in RCA: 222] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/07/2017] [Accepted: 12/09/2017] [Indexed: 02/06/2023]
Abstract
Type IV secretion systems (T4SSs) are versatile multiprotein nanomachines spanning the entire cell envelope in Gram-negative and Gram-positive bacteria. They play important roles through the contact-dependent secretion of effector molecules into eukaryotic hosts and conjugative transfer of mobile DNA elements as well as contact-independent exchange of DNA with the extracellular milieu. In the last few years, many details on the molecular mechanisms of T4SSs have been elucidated. Exciting structures of T4SS complexes from Escherichia coli plasmids R388 and pKM101, Helicobacter pylori and Legionella pneumophila have been solved. The structure of the F-pilus was also reported and surprisingly revealed a filament composed of pilin subunits in 1:1 stoichiometry with phospholipid molecules. Many new T4SSs have been identified and characterized, underscoring the structural and functional diversity of this secretion superfamily. Complex regulatory circuits also have been shown to control T4SS machine production in response to host cell physiological status or a quorum of bacterial recipient cells in the vicinity. Here, we summarize recent advances in our knowledge of 'paradigmatic' and emerging systems, and further explore how new basic insights are aiding in the design of strategies aimed at suppressing T4SS functions in bacterial infections and spread of antimicrobial resistances.
Collapse
Affiliation(s)
- Elisabeth Grohmann
- Beuth University of Applied Sciences Berlin, Life Sciences and Technology, D-13347 Berlin, Germany
| | - Peter J. Christie
- Department of Microbiology and Molecular Genetics, The University of Texas Medical School at Houston, 6431 Fannin St, Houston, Texas 77030, USA
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, London WC1E 7HX, United Kingdom
| | - Steffen Backert
- Friedrich Alexander University Erlangen-Nuremberg, Department of Biology, Division of Microbiology, Staudtstrasse 5, D-91058 Erlangen, Germany
| |
Collapse
|
8
|
Grohmann E, Keller W, Muth G. Mechanisms of Conjugative Transfer and Type IV Secretion-Mediated Effector Transport in Gram-Positive Bacteria. Curr Top Microbiol Immunol 2017. [PMID: 29536357 DOI: 10.1007/978-3-319-75241-9_5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Conjugative DNA transfer is the most important means to transfer antibiotic resistance genes and virulence determinants encoded by plasmids, integrative conjugative elements (ICE), and pathogenicity islands among bacteria. In gram-positive bacteria, there exist two types of conjugative systems, (i) type IV secretion system (T4SS)-dependent ones, like those encoded by the Enterococcus, Streptococcus, Staphylococcus, Bacillus, and Clostridia mobile genetic elements and (ii) T4SS-independent ones, as those found on Streptomyces plasmids. Interestingly, very recently, on the Streptococcus suis genome, the first gram-positive T4SS not only involved in conjugative DNA transfer but also in effector translocation to the host was detected. Although no T4SS core complex structure from gram-positive bacteria is available, several structures from T4SS protein key factors from Enterococcus and Clostridia plasmids have been solved. In this chapter, we summarize the current knowledge on the molecular mechanisms and structure-function relationships of the diverse conjugation machineries and emerging research needs focused on combatting infections and spread of multiple resistant gram-positive pathogens.
Collapse
Affiliation(s)
- Elisabeth Grohmann
- Beuth University of Applied Sciences Berlin, Life Sciences and Technology, 13347, Berlin, Germany.
| | - Walter Keller
- Institute of Molecular Biosciences, BioTechMed, University of Graz, 8010, Graz, Austria
| | - Günther Muth
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University Tübingen, 72076, Tübingen, Germany
| |
Collapse
|