1
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Turner RJ. The good, the bad, and the ugly of metals as antimicrobials. Biometals 2024; 37:545-559. [PMID: 38112899 PMCID: PMC11101337 DOI: 10.1007/s10534-023-00565-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 11/18/2023] [Indexed: 12/21/2023]
Abstract
We are now moving into the antimicrobial resistance (AMR) era where more antibiotic resistant bacteria are now the majority, a problem brought on by both misuse and over use of antibiotics. Unfortunately, the antibiotic development pipeline dwindled away over the past decades as they are not very profitable compounds for companies to develop. Regardless researchers over the past decade have made strides to explore alternative options and out of this we see revisiting historical infection control agents such as toxic metals. From this we now see a field of research exploring the efficacy of metal ions and metal complexes as antimicrobials. Such antimicrobials are delivered in a variety of forms from metal salts, alloys, metal complexes, organometallic compounds, and metal based nanomaterials and gives us the broad term metalloantimicrobials. We now see many effective formulations applied for various applications using metals as antimicrobials that are effective against drug resistant strains. The purpose of the document here is to step aside and begin a conversation on the issues of use of such toxic metal compounds against microbes. This critical opinion mini-review in no way aims to be comprehensive. The goal here is to understand the benefits of metalloantimicrobials, but also to consider strongly the disadvantages of using metals, and what are the potential consequences of misuse and overuse. We need to be conscious of the issues, to see the entire system and affect through a OneHealth vision.
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Affiliation(s)
- Raymond J Turner
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, Canada.
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2
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Lorenzetti L, Brandolini M, Gatti G, Bernardi E, Chiavari C, Gualandi P, Galliani G, Sambri V, Martini C. Cu-based thin rolled foils: relationship among alloy composition, micromechanical and antiviral properties against SARS-CoV-2. Heliyon 2024; 10:e28238. [PMID: 38560697 PMCID: PMC10979200 DOI: 10.1016/j.heliyon.2024.e28238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 04/04/2024] Open
Abstract
The healthcare-associated infections (HAIs) and pandemics caused by multidrug-resistant (MDR) and new-generation pathogens threaten the whole world community. Cu and its alloys have been attracting widespread interest as anti-contamination materials due to the rapid inactivation of MDR-superbugs and viruses. Applying thin Cu-based foils on pre-existing surfaces in hygiene-sensitive areas represents a quick, simple, cost-effective self-sanitising practice. However, the influence of chemical composition and microstructure should be deeply investigated when evaluating the antimicrobial capability and durability of Cu-based materials. The effect of composition on micromechanical and antiviral properties was investigated by comparing Cu15Zn and Cu18Ni20Zn (foil thickness from 13 to 27 μm) with Phosphorous High-Conductivity (PHC) Cu. The influence of recrystallisation annealing of PHC Cu was also investigated. Microstructural characterisation was carried out by optical (OM) and scanning electron (FEG-SEM) microscopy, Energy-dispersive Spectroscopy (EDS) and Electron-Backscattered Diffraction (EBSD). The micromechanical behaviour was assessed by microhardness, microscale abrasion and scratch tests. Cu-based foils were exposed to SARS-CoV-2 for different time points in quasi-dry conditions (artificial sweat solution), evaluating their antiviral capability by quantitative Reverse-Transcriptase Polymerase Chain Reaction (qRT-PCR). Surface morphology, contact angle measurements and Cu release were measured. All Cu-based surfaces completely inactivated SARS-CoV-2 in 10 min: pure Cu was the best option regarding antiviral efficiency, while Cu15Zn showed the best trade-off between micromechanical and antiviral properties.
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Affiliation(s)
- L. Lorenzetti
- Dept. Industrial Engineering (DIN), University of Bologna, Viale Risorgimento 4, 40136 Bologna, Italy
| | - M. Brandolini
- Unit of Microbiology, The Great Romagna Hub Laboratory, Piazza della Liberazione 60, 47522 Pievesestina, Italy
- Dept. Medical and Surgical Sciences (DIMEC), University of Bologna, Via Irnerio 49, 40126 Bologna, Italy
| | - G. Gatti
- Unit of Microbiology, The Great Romagna Hub Laboratory, Piazza della Liberazione 60, 47522 Pievesestina, Italy
- Dept. Medical and Surgical Sciences (DIMEC), University of Bologna, Via Irnerio 49, 40126 Bologna, Italy
| | - E. Bernardi
- Dept. Industrial Chemistry "Toso Montanari", University of Bologna, Via Piero Gobetti 85, Bologna 40129, Italy
| | - C. Chiavari
- Dept. Cultural Heritage (DBC), University of Bologna, Via degli Ariani 1, 48121 Ravenna, Italy
| | - P. Gualandi
- Pietro Galliani SpA, Via Molino Malpasso 65, 40038 Vergato (BO), Italy
| | - G. Galliani
- Pietro Galliani SpA, Via Molino Malpasso 65, 40038 Vergato (BO), Italy
| | - V. Sambri
- Unit of Microbiology, The Great Romagna Hub Laboratory, Piazza della Liberazione 60, 47522 Pievesestina, Italy
- Dept. Medical and Surgical Sciences (DIMEC), University of Bologna, Via Irnerio 49, 40126 Bologna, Italy
| | - C. Martini
- Dept. Industrial Engineering (DIN), University of Bologna, Viale Risorgimento 4, 40136 Bologna, Italy
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Graziani G, Ghezzi D, Nudelman F, Sassoni E, Laidlaw F, Cappelletti M, Boi M, Borciani G, Milita S, Bianchi M, Baldini N, Falini G. A natural biogenic fluorapatite as a new biomaterial for orthopedics and dentistry: antibacterial activity of lingula seashell and its use for nanostructured biomimetic coatings. J Mater Chem B 2024; 12:2083-2098. [PMID: 38284627 DOI: 10.1039/d3tb02454g] [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: 01/30/2024]
Abstract
Calcium phosphates are widely studied in orthopedics and dentistry, to obtain biomimetic and antibacterial implants. However, the multi-substituted composition of mineralized tissues is not fully reproducible from synthetic procedures. Here, for the first time, we investigate the possible use of a natural, fluorapatite-based material, i.e., Lingula anatina seashell, resembling the composition of bone and enamel, as a biomaterial source for orthopedics and dentistry. Indeed, thanks to its unique mineralization process and conditions, L. anatina seashell is among the few natural apatite-based shells, and naturally contains ions having possible antibacterial efficacy, i.e., fluorine and zinc. After characterization, we explore its deposition by ionized jet deposition (IJD), to obtain nanostructured coatings for implantable devices. For the first time, we demonstrate that L. anatina seashells have strong antibacterial properties. Indeed, they significantly inhibit planktonic growth and cell adhesion of both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The two strains show different susceptibility to the mineral and organic parts of the seashells, the first being more susceptible to zinc and fluorine in the mineral part, and the second to the organic (chitin-based) component. Upon deposition by IJD, all films exhibit a nanostructured morphology and sub-micrometric thickness. The multi-doped, complex composition of the target is maintained in the coating, demonstrating the feasibility of deposition of coatings starting from biogenic precursors (seashells). In conclusion, Lingula seashell-based coatings are non-cytotoxic with strong antimicrobial capability, especially against Gram-positive strains, consistently with their higher susceptibility to fluorine and zinc. Importantly, these properties are improved compared to synthetic fluorapatite, showing that the films are promising for antimicrobial applications.
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Affiliation(s)
- Gabriela Graziani
- Biomedical Science, Technologies, and Nanobiotecnology Lab, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy. gabriela.graziani(at)polimi.it
| | - Daniele Ghezzi
- Biomedical Science, Technologies, and Nanobiotecnology Lab, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy. gabriela.graziani(at)polimi.it
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Fabio Nudelman
- EaStCHEM School of Chemistry, The University of Edinburgh, Edinburgh, UK
| | - Enrico Sassoni
- Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Bologna, Italy
| | - Fraser Laidlaw
- School of Physics and Astronomy, The University of Edinburgh, Edinburgh, UK
| | - Martina Cappelletti
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Marco Boi
- Biomedical Science, Technologies, and Nanobiotecnology Lab, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy. gabriela.graziani(at)polimi.it
| | - Giorgia Borciani
- Biomedical Science, Technologies, and Nanobiotecnology Lab, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy. gabriela.graziani(at)polimi.it
| | - Silvia Milita
- CNR-Institute for Microelectronic and Microsystems, Bologna, Italy
| | - Michele Bianchi
- Department of Life Sciences, Università di Modena e Reggio Emilia, Modena, Italy
| | - Nicola Baldini
- Biomedical Science, Technologies, and Nanobiotecnology Lab, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy. gabriela.graziani(at)polimi.it
- University of Bologna, Department of Biomedical and Neuromotor Sciences, Bologna, Italy
| | - Giuseppe Falini
- Department of Chemistry "Giacomo Ciamician", University of Bologna, Bologna, Italy. giuseppe.falini(at)unibo.it
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4
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Zhai S, Tian Y, Shi X, Liu Y, You J, Yang Z, Wu Y, Chu S. Overview of strategies to improve the antibacterial property of dental implants. Front Bioeng Biotechnol 2023; 11:1267128. [PMID: 37829564 PMCID: PMC10565119 DOI: 10.3389/fbioe.2023.1267128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/14/2023] [Indexed: 10/14/2023] Open
Abstract
The increasing number of peri-implant diseases and the unsatisfactory results of conventional treatment are causing great concern to patients and medical staff. The effective removal of plaque which is one of the key causes of peri-implant disease from the surface of implants has become one of the main problems to be solved urgently in the field of peri-implant disease prevention and treatment. In recent years, with the advancement of materials science and pharmacology, a lot of research has been conducted to enhance the implant antimicrobial properties, including the addition of antimicrobial coatings on the implant surface, the adjustment of implant surface topography, and the development of new implant materials, and significant progress has been made in various aspects. Antimicrobial materials have shown promising applications in the prevention of peri-implant diseases, but meanwhile, there are some shortcomings, which leads to the lack of clinical widespread use of antimicrobial materials. This paper summarizes the research on antimicrobial materials applied to implants in recent years and presents an outlook on the future development.
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Affiliation(s)
| | | | | | | | | | | | | | - Shunli Chu
- Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling, Hospital of Stomatology, Jilin University, Changchun, China
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5
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Exploring the Co-Crystallization of Kojic Acid with Silver(I), Copper(II), Zinc(II), and Gallium(III) for Potential Antibacterial Applications. Molecules 2023; 28:molecules28031244. [PMID: 36770910 PMCID: PMC9920434 DOI: 10.3390/molecules28031244] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/13/2023] [Accepted: 01/24/2023] [Indexed: 01/31/2023] Open
Abstract
Co-crystallization of kojic acid (HKA) with silver(I), copper(II), zinc(II), or gallium(III) salts yielded three 1D coordination polymers and one 0D complex in which kojic acid was present as a neutral or anionic terminal or bridging ligand. All reactions were conducted mechanochemically via ball milling and manual grinding, or via slurry. All solids were fully characterized via single-crystal and/or powder X-ray diffraction. As kojic acid is a mild antimicrobial compound that is widely used in cosmetics, and the metal cations possess antibacterial properties, their combinations were tested for potential antibacterial applications. The minimal inhibition concentrations (MICs) and minimal biocidal concentrations (MBCs) for all compounds were measured against standard strains of the bacteria P. aeruginosa, S. aureus, and E. coli. All compounds exerted appreciable antimicrobial activity in the order of silver, zinc, copper, and gallium complexes.
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6
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Antibacterial and Antibiofilm Activity of Nanostructured Copper Films Prepared by Ionized Jet Deposition. Antibiotics (Basel) 2022; 12:antibiotics12010055. [PMID: 36671256 PMCID: PMC9854604 DOI: 10.3390/antibiotics12010055] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 12/31/2022] Open
Abstract
Metal coatings represent good strategies to functionalize surfaces/devices and limit bacterial contamination/colonization thanks to their pleiotropic activity and their ability to prevent the biofilm formation. Here, we investigated the antibacterial and antibiofilm capacity of copper coatings deposited through the Ionized Jet Deposition (IJD) on the Calgary Biofilm Device (CBD) against the growth of two gram-negative and two gram-positive pathogenic strains. Three areas (i.e., (+)Cu, (++)Cu, and (+++)Cu based on the metal amount) on the CBD were obtained, presenting nanostructured coatings with high surface homogeneity and increasing dimensions of aggregates from the CBD periphery to the centre. The coatings in (++)Cu and (+++)Cu were efficient against the planktonic growth of the four pathogens. This antibacterial effect decreased in (+)Cu but was still significant for most of the pathogens. The antibiofilm efficacy was significant for all the strains and on both coated and uncoated surfaces in (+++)Cu, whereas in (++)Cu the only biofilms forming on the coated surfaces were inhibited, suggesting that the decrease of the metal on the coatings was associated to a reduced metal ion release. In conclusion, this work demonstrates that Cu coatings deposited by IJD have antibacterial and antibiofilm activity against a broad range of pathogens indicating their possible application to functionalize biomedical devices.
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7
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Antimicrobial activity of supramolecular salts of gallium(III) and proflavine and the intriguing case of a trioxalate complex. Sci Rep 2022; 12:3673. [PMID: 35256712 PMCID: PMC8901752 DOI: 10.1038/s41598-022-07813-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 02/25/2022] [Indexed: 12/24/2022] Open
Abstract
The use of the gallium oxalate complex [Ga(ox)3]3- as a building block in the formation of a drug-drug salt with the antimicrobial agent proflavine (PF) as its proflavinium cation (HPF+), namely [HPF]3[Ga(ox)3]·4H2O, is reported together with the preparation of the potassium salt K3[Ga(ox)3] and the novel dimeric gallium(III) salt K4[Ga2(ox)4(μ-OH)2]·2H2O. All compounds have been characterized by solid state methods, and their performance as antimicrobial agents has been evaluated by disk diffusion assay against the bacteria strains Pseudomonas aeruginosa ATCC27853, Staphylococcus aureus ATCC25923, and Escherichia coli ATCC25922. While the [HPF]3[Ga(ox)3]·4H2O drug-drug salt is effective against all three strains, the gallium oxalate salt K3[Ga(ox)3] showed impressive selectivity towards P. aeruginosa, with little to no antimicrobial activity against the other two organisms. This work presents novel breakthroughs towards Ga based antimicrobial agents.
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8
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Zheng TX, Li W, Gu YY, Zhao D, Qi MC. Classification and research progress of implant surface antimicrobial techniques. J Dent Sci 2022; 17:1-7. [PMID: 35028014 PMCID: PMC8739780 DOI: 10.1016/j.jds.2021.08.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/30/2021] [Indexed: 12/13/2022] Open
Abstract
Due to the good biocompatibility and ideal mechanical property, titanium implants have been widely used in dental clinic and orthopedic surgery. However, bacteria induced infection can cause per-implant inflammation and decrease the success rate of implant surgery. Therefore, developing antimicrobial techniques is essential to successful application of titanium implants. Many surface antimicrobial techniques, including antimicrobial coating and surface modifications, have been explored and they always exert antimicrobial effect by reducing bacterial adhesion, inhibiting their metabolism, or destructing cell structure. In this paper, different surface antimicrobial techniques and their recent research progress are reviewed to provide a brief insight on this area.
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Affiliation(s)
| | | | | | | | - Meng-Chun Qi
- Corresponding author. Department of Oral & Maxillofacial Surgery, College of stomatology, North China University of Science and Technology, No.21 Bohai Road, District of Caofeidian, Tangshan City, 063200, Hebei Province, PR China.
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9
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Multiple Ion Scaffold-Based Delivery Platform for Potential Application in Early Stages of Bone Regeneration. MATERIALS 2021; 14:ma14247676. [PMID: 34947272 PMCID: PMC8706177 DOI: 10.3390/ma14247676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/10/2021] [Accepted: 12/07/2021] [Indexed: 11/16/2022]
Abstract
Bone has the intrinsic capacity to regenerate itself, as long as the damage is small, through the sequential stimulation of specific phases, such as angiogenesis followed by osteogenesis. However, when the damage is extensive it is unable to regenerate and bone tissue engineering is used as an alternative. In this study, we developed a platform to allow the triple ion delivery with sequential delivery capacity to potentially stimulate antibacterial, angiogenic and osteogenic processes. The scaffold-based platform consisted of alginate/hydroxyapatite (HA) microparticles embedded in alginate fibers. Firstly, microparticles were developed using different ratios of alginate:HA using the spraying method, resulting in a high reproducibility of the technique. Microparticle size between 100–300 µm and ratio 1:40 resulted in a more spherical morphology and were selected for their incorporation into alginate fiber. Different amounts of copper and cobalt were added with the microparticles and alginate fiber, respectively, were used as model ions which could eventually modulate and mimic antimicrobial and angiogenic processes. Moreover, calcium ion was also incorporated in both, in order to provide the system with potential osteogenic properties together with HA. The multiple delivery of copper, cobalt and calcium released were in the therapeutic range as measured by induced coupled plasma (ICP), providing a promising delivery strategy for tissue engineering.
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10
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Gugala N, Salazar-Alemán DA, Chua G, Turner RJ. Using a chemical genetic screen to enhance our understanding of the antimicrobial properties of copper. Metallomics 2021; 14:6449381. [PMID: 34865058 DOI: 10.1093/mtomcs/mfab071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 11/30/2021] [Indexed: 11/12/2022]
Abstract
The competitive toxic and stress inducing nature of copper necessitates systems that sequester and export this metal from the cytoplasm of bacterial cells. Several predicted mechanisms of toxicity include the production of reactive oxygen species, thiol depletion, DNA and iron-sulfur cluster disruption. Accompanying these mechanisms include pathways of homeostasis such as chelation, oxidation, and transport. Still, the mechanisms of copper resistance and sensitivity are not fully understood. Furthermore, studies fail to recognize that the response to copper is likely a result of numerous mechanisms, as in the case for homeostasis, in which proteins and enzymes work as a collective to maintain appropriate copper concentrations. In this study we used the Keio collection, an array of 3985 Escherichia coli mutants, each with a deleted non-essential gene, to gain a better understanding of prolonged copper exposure. In short, we recovered two copper homeostatic gene and genes involved in transporting and assembling to be involved in mediating prolonged copper stress under the conditions assessed. The gene coding for the protein TolC was uncovered as a sensitive hit and we demonstrated that tolC, an outer membrane efflux channel, is key in mitigating copper sensitivity. Additionally, the activity of tRNA processing was enriched and the deletion of several proteins involved in import generated copper tolerance. Lastly, key genes belonging to central carbon metabolism and nicotinamide adenine dinucleotide biosynthesis were uncovered as tolerant hits. Overall, this study shows that copper sensitivity and tolerance are a result of numerous mechanisms acting in combination within the cell.
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Affiliation(s)
- Natalie Gugala
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | | | - Gordon Chua
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
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11
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Xiong S, Zhang P, Xia Y, Zou Q, Jiang M, Gai J. Unique antimicrobial/thermally conductive polymer composites for use in medical electronic devices. J Appl Polym Sci 2021. [DOI: 10.1002/app.50113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Si‐Wei Xiong
- State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan University Chengdu Sichuan China
| | - Pan Zhang
- State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan University Chengdu Sichuan China
| | - Yu Xia
- State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan University Chengdu Sichuan China
| | - Qian Zou
- State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan University Chengdu Sichuan China
| | - Meng‐ying Jiang
- State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan University Chengdu Sichuan China
| | - Jing‐Gang Gai
- State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan University Chengdu Sichuan China
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12
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Mass spectrometry based targeted metabolomics precisely characterized new functional metabolites that regulate biofilm formation in Escherichia coli. Anal Chim Acta 2021; 1145:26-36. [DOI: 10.1016/j.aca.2020.12.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 12/08/2020] [Accepted: 12/14/2020] [Indexed: 12/17/2022]
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13
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Pormohammad A, Monych NK, Turner RJ. Zinc and SARS‑CoV‑2: A molecular modeling study of Zn interactions with RNA‑dependent RNA‑polymerase and 3C‑like proteinase enzymes. Int J Mol Med 2021; 47:326-334. [PMID: 33236142 PMCID: PMC7723401 DOI: 10.3892/ijmm.2020.4790] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 10/13/2020] [Indexed: 11/09/2022] Open
Abstract
RNA‑dependent RNA‑polymerase (RdRp) and 3C‑like proteinase (3CLpro) are two main enzymes that play a key role in the replication of SARS‑CoV‑2. Zinc (Zn) has strong immunogenic properties and is known to bind to a number of proteins, modulating their activities. Zn also has a history of use in viral infection control. Thus, the present study models potential Zn binding to RdRp and the 3CLpro. Through molecular modeling, the Zn binding sites in the aforementioned two important enzymes of viral replication were found to be conserved between severe acute respiratory syndrome (SARS)‑coronavirus (CoV) and SARS‑CoV‑2. The location of these sites may influence the enzymatic activity of 3CLpro and RdRp in coronavirus disease 2019 (COVID‑19). Since Zn has established immune health benefits, is readily available, non‑expensive and a safe food supplement, with the comparisons presented here between SARS‑CoV and COVID‑19, the present study proposes that Zn could help ameliorate the disease process of COVID‑19 infection.
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Affiliation(s)
- Ali Pormohammad
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N4V8, Canada
| | - Nadia K. Monych
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N4V8, Canada
| | - Raymond J. Turner
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N4V8, Canada
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14
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Pormohammad A, Turner RJ. Silver Antibacterial Synergism Activities with Eight Other Metal(loid)-Based Antimicrobials against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Antibiotics (Basel) 2020; 9:antibiotics9120853. [PMID: 33260495 PMCID: PMC7760997 DOI: 10.3390/antibiotics9120853] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 11/26/2020] [Accepted: 11/27/2020] [Indexed: 11/16/2022] Open
Abstract
The present study surveys potential antibacterial synergism effects of silver nitrate with eight other metal or metalloid-based antimicrobials (MBAs), including silver nitrate, copper (II) sulfate, gallium (III) nitrate, nickel sulfate, hydrogen tetrachloroaurate (III) trihydrate (gold), aluminum sulfate, sodium selenite, potassium tellurite, and zinc sulfate. Bacteriostatic and bactericidal susceptibility testing explored antibacterial synergism potency of 5760 combinations of MBAs against three bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus) in three different media. Silver nitrate in combination with potassium tellurite, zinc sulfate, and tetrachloroaurate trihydrate had remarkable bactericidal and bacteriostatic synergism effects. Synergism properties of MBAs decreased effective antibacterial concentrations remarkably and bacterial cell count decreased by 8.72 log10 colony-forming units (CFU)/mL in E. coli, 9.8 log10 CFU/mL in S. aureus, and 12.3 log10 CFU/mL in P. aeruginosa, compared to each MBA alone. Furthermore, most of the MBA combinations inhibited the recovery of bacteria; for instance, the combination of silver nitrate–tetrachloroaurate against P. aeruginosa inhibited the recovery of bacteria, while three-fold higher concentration of silver nitrate and two-fold higher concentration of tetrachloroaurate were required for inhibition of recovery when used individually. Overall, higher synergism was typically obtained in simulated wound fluid (SWF) rather than laboratory media. Unexpectedly, the combination of A silver nitrate–potassium tellurite had antagonistic bacteriostatic effects in Luria broth (LB) media for all three strains, while the combination of silver nitrate–potassium tellurite had the highest bacteriostatic and bactericidal synergism in SWF. Here, we identify the most effective antibacterial MBAs formulated against each of the Gram-positive and Gram-negative pathogen indicator strains.
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15
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Neill CJ, Harris S, Goldstone RJ, Lau ECHT, Henry TB, Yiu HHP, Smith DGE. Antibacterial Activities of Ga(III) against E. coli Are Substantially Impacted by Fe(III) Uptake Systems and Multidrug Resistance in Combination with Oxygen Levels. ACS Infect Dis 2020; 6:2959-2969. [PMID: 32960047 DOI: 10.1021/acsinfecdis.0c00425] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The continued emergence and spread of antimicrobial resistance (AMR), particularly multidrug resistant (MDR) bacteria, are increasing threats driving the search for additional and alternative antimicrobial agents. The World Health Organization (WHO) has categorized bacterial risk levels and includes Escherichia coli among the highest priority, making this both a convenient model bacterium and a clinically highly relevant species on which to base investigations of antimicrobials. Among many compounds examined for use as antimicrobials, Ga(III) complexes have shown promise. Nonetheless, the spectrum of activities, susceptibility of bacterial species, mechanisms of antimicrobial action, and bacterial characteristics influencing antibacterial actions are far from being completely understood; these are important considerations for any implementation of an effective antibacterial agent. In this investigation, we show that an alteration in growth conditions to physiologically relevant lowered oxygen (anaerobic) conditions substantially increases the minimum inhibitory concentrations (MICs) of Ga(III) required to inhibit growth for 46 wild-type E. coli strains. Several studies have implicated a Trojan horse hypothesis wherein bacterial Fe uptake systems have been linked to the promotion of Ga(III) uptake and result in enhanced antibacterial activity. Our studies show that, conversely, the carriage of accessory Fe uptake systems (Fe_acc) significantly increased the concentrations of Ga(III) required for antibacterial action. Similarly, it is shown that MDR strains are more resistant to Ga(III). The increased tolerance of Fe_acc/MDR strains was apparent under anaerobic conditions. This phenomenon of heightened tolerance has not previously been shown although the mechanisms remain to be defined. Nonetheless, this further highlights the significant contributions of bacterial metabolism, fitness, and AMR characteristics and their implications in evaluating novel antimicrobials.
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Affiliation(s)
- Christopher J. Neill
- The Institute of Biological Chemistry, Biophysics and Bioengineering (IB3), School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Susan Harris
- The Institute of Biological Chemistry, Biophysics and Bioengineering (IB3), School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Robert J. Goldstone
- The Institute of Biological Chemistry, Biophysics and Bioengineering (IB3), School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Elizabeth C. H. T. Lau
- Chemical Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Theodore B. Henry
- The Institute of Life and Earth Sciences (ILES), School of Energy, Geoscience, Infrastructure and Society, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Humphrey H. P. Yiu
- Chemical Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - David G. E. Smith
- The Institute of Biological Chemistry, Biophysics and Bioengineering (IB3), School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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16
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Copper-Polyurethane Composite Materials: Particle Size Effect on the Physical-Chemical and Antibacterial Properties. Polymers (Basel) 2020; 12:polym12091934. [PMID: 32867134 PMCID: PMC7563828 DOI: 10.3390/polym12091934] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 07/24/2020] [Accepted: 07/28/2020] [Indexed: 12/20/2022] Open
Abstract
In this work, thermoplastic polyurethane (TPU) composites incorporated with 1.0 wt% Cu particles were synthesized by the melt blending method. The effect of the incorporated copper particle size on the antibacterial, thermal, rheological, and mechanical properties of TPU was investigated. The obtained results showed that (i) the addition of copper particles increased the thermal and mechanical properties because they acted as co-stabilizers of polyurethane (PU) (ii) copper nanoparticles decreased the viscosity of composite melts, and (iii) microparticles > 0.5 µm had a tendency to easily increase the maximum torque and formation of agglomerates. SEM micrographics showed that a good mixture between TPU and copper particles was obtained by the extrusion process. Additionally, copper-TPU composite materials effectively inhibited the growth of the Gram-negative Escherichia coli and the Gram-positive Staphylococcus aureus. Considering that the natural concentration of copper in the blood is in the range of 0.7-0.12 mg/L and that the total migration value of copper particles from TPU was 1000 times lower, the results suggested that TPU nanocomposites could be adequately employed for biomedical applications without a risk of contamination.
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17
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Rosenberg M, Visnapuu M, Vija H, Kisand V, Kasemets K, Kahru A, Ivask A. Selective antibiofilm properties and biocompatibility of nano-ZnO and nano-ZnO/Ag coated surfaces. Sci Rep 2020; 10:13478. [PMID: 32778787 PMCID: PMC7417576 DOI: 10.1038/s41598-020-70169-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/06/2020] [Indexed: 12/16/2022] Open
Abstract
Spread of pathogenic microbes and antibiotic-resistant bacteria in health-care settings and public spaces is a serious public health challenge. Materials that prevent solid surface colonization or impede touch-transfer of viable microbes could provide means to decrease pathogen transfer from high-touch surfaces in critical applications. ZnO and Ag nanoparticles have shown great potential in antimicrobial applications. Less is known about nano-enabled surfaces. Here we demonstrate that surfaces coated with nano-ZnO or nano-ZnO/Ag composites are not cytotoxic to human keratinocytes and possess species-selective medium-dependent antibiofilm activity against Escherichia coli, Staphylococcus aureus and Candida albicans. Colonization of nano-ZnO and nano-ZnO/Ag surfaces by E. coli and S. aureus was decreased in static oligotrophic conditions (no planktonic growth). Moderate to no effect was observed for bacterial biofilms in growth medium (supporting exponential growth). Inversely, nano-ZnO surfaces enhanced biofilm formation by C. albicans in oligotrophic conditions. However, enhanced C. albicans biofilm formation on nano-ZnO surfaces was effectively counteracted by the addition of Ag. Possible selective enhancement of biofilm formation by the yeast C. albicans on Zn-enabled surfaces should be taken into account in antimicrobial surface development. Our results also indicated the importance of the use of application-appropriate test conditions and exposure medium in antimicrobial surface testing.
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Affiliation(s)
- M Rosenberg
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia.
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia.
| | - M Visnapuu
- Institute of Physics, University of Tartu, Tartu, Estonia
| | - H Vija
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - V Kisand
- Institute of Physics, University of Tartu, Tartu, Estonia
| | - K Kasemets
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - A Kahru
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
- Estonian Academy of Sciences, Tallinn, Estonia
| | - A Ivask
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
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18
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Vargas-Straube MJ, Beard S, Norambuena R, Paradela A, Vera M, Jerez CA. High copper concentration reduces biofilm formation in Acidithiobacillus ferrooxidans by decreasing production of extracellular polymeric substances and its adherence to elemental sulfur. J Proteomics 2020; 225:103874. [PMID: 32569817 DOI: 10.1016/j.jprot.2020.103874] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/04/2020] [Accepted: 06/06/2020] [Indexed: 12/14/2022]
Abstract
Acidithiobacillus ferrooxidans is an acidophilic bacterium able to grow in environments with high concentrations of metals. It is a chemolithoautotroph able to form biofilms on the surface of solid minerals to obtain its energy. The response of both planktonic and sessile cells of A. ferrooxidans ATCC 23270 grown in elemental sulfur and adapted to high copper concentration was analyzed by quantitative proteomics. It was found that 137 proteins varied their abundance when comparing both lifestyles. Copper effllux proteins, some subunits of the ATP synthase complex, porins, and proteins involved in cell wall modification increased their abundance in copper-adapted sessile lifestyle cells. On the other hand, planktonic copper-adapted cells showed increased levels of proteins such as: cupreredoxins involved in copper cell sequestration, some proteins related to sulfur metabolism, those involved in biosynthesis and transport of lipopolysaccharides, and in assembly of type IV pili. During copper adaptation a decreased formation of biofilms was measured as determined by epifluorescence microscopy. This was apparently due not only to a diminished number of sessile cells but also to their exopolysaccharides production. This is the first study showing that copper, a prevalent metal in biomining environments causes dispersion of A. ferrooxidans biofilms. SIGNIFICANCE: Copper is a metal frequently found in high concentrations at mining environments inhabitated by acidophilic microorganisms. Copper resistance determinants of A. ferrooxidans have been previously studied in planktonic cells. Although biofilms are recurrent in these types of environments, the effect of copper on their formation has not been studied so far. The results obtained indicate that high concentrations of copper reduce the capacity of A. ferrooxidans ATCC 23270 to form biofilms on sulfur. These findings may be relevant to consider for a bacterium widely used in copper bioleaching processes.
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Affiliation(s)
- M J Vargas-Straube
- Laboratory of Molecular Microbiology and Biotechnology, Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile
| | - S Beard
- Fundación Ciencia y Vida, Santiago, Chile
| | - R Norambuena
- Laboratory of Molecular Microbiology and Biotechnology, Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile
| | - A Paradela
- Proteomics Laboratory, National Biotechnology Center, CSIC, Madrid, Spain
| | - M Vera
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.; Department of Hydraulic and Environmental Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - C A Jerez
- Laboratory of Molecular Microbiology and Biotechnology, Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile..
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19
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Ferreira M, Bessa LJ, Sousa CF, Eaton P, Bongiorno D, Stefani S, Campanile F, Gameiro P. Fluoroquinolone Metalloantibiotics: A Promising Approach against Methicillin-Resistant Staphylococcus aureus. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17093127. [PMID: 32365881 PMCID: PMC7246690 DOI: 10.3390/ijerph17093127] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 04/27/2020] [Accepted: 04/28/2020] [Indexed: 12/24/2022]
Abstract
Fluoroquinolones (FQs) are antibiotics commonly used in clinical practice, although nowadays they are becoming ineffective due to the emergence of several mechanisms of resistance in most bacteria. The complexation of FQs with divalent metal ions and phenanthroline (phen) is a possible approach to circumvent antimicrobial resistance, since it forms very stable complexes known as metalloantibiotics. This work is aimed at determining the antimicrobial activity of metalloantibiotics of Cu(II)FQphen against a panel of multidrug-resistant (MDR) clinical isolates and to clarify their mechanism of action. Minimum inhibitory concentrations (MICs) were determined against MDR isolates of Escherichia coli, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA). Metalloantibiotics showed improved antimicrobial activity against several clinical isolates, especially MRSA. Synergistic activity was evaluated in combination with ciprofloxacin and ampicillin by the disk diffusion and checkerboard methods. Synergistic and additive effects were shown against MRSA isolates. The mechanism of action was studied though enzymatic assays and atomic force microscopy (AFM) experiments. The results indicate a similar mechanism of action for FQs and metalloantibiotics. In summary, metalloantibiotics seem to be an effective alternative to pure FQs against MRSA. The results obtained in this work open the way to the screening of metalloantibiotics against other Gram-positive bacteria.
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Affiliation(s)
- Mariana Ferreira
- REQUIMTE-LAQV (Rede de Química e Tecnologia – Laboratório Associado para a Química Verde), Departamento de Química e Bioquímica da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal; (L.J.B.); (C.F.S.); (P.E.); (P.G.)
- Correspondence:
| | - Lucinda J. Bessa
- REQUIMTE-LAQV (Rede de Química e Tecnologia – Laboratório Associado para a Química Verde), Departamento de Química e Bioquímica da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal; (L.J.B.); (C.F.S.); (P.E.); (P.G.)
| | - Carla F. Sousa
- REQUIMTE-LAQV (Rede de Química e Tecnologia – Laboratório Associado para a Química Verde), Departamento de Química e Bioquímica da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal; (L.J.B.); (C.F.S.); (P.E.); (P.G.)
| | - Peter Eaton
- REQUIMTE-LAQV (Rede de Química e Tecnologia – Laboratório Associado para a Química Verde), Departamento de Química e Bioquímica da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal; (L.J.B.); (C.F.S.); (P.E.); (P.G.)
| | - Dafne Bongiorno
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy; (D.B.); (S.S.); (F.C.)
| | - Stefania Stefani
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy; (D.B.); (S.S.); (F.C.)
| | - Floriana Campanile
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy; (D.B.); (S.S.); (F.C.)
| | - Paula Gameiro
- REQUIMTE-LAQV (Rede de Química e Tecnologia – Laboratório Associado para a Química Verde), Departamento de Química e Bioquímica da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal; (L.J.B.); (C.F.S.); (P.E.); (P.G.)
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20
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Shemchuk O, Braga D, Grepioni F, Turner RJ. Co-crystallization of antibacterials with inorganic salts: paving the way to activity enhancement. RSC Adv 2020; 10:2146-2149. [PMID: 35494556 PMCID: PMC9048849 DOI: 10.1039/c9ra10353h] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 01/06/2020] [Indexed: 12/12/2022] Open
Abstract
Co-crystallization of the antibacterial agents proflavine and methyl viologen with the inorganic salts CuCl, CuCl2 and AgNO3 results in enhanced antimicrobial activity with respect to the separate components.
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Affiliation(s)
- Oleksii Shemchuk
- Molecular Crystal Engineering Laboratory
- Dipartimento di Chimica “G. Ciamician”
- Università di Bologna
- 40126 Bologna
- Italy
| | - Dario Braga
- Molecular Crystal Engineering Laboratory
- Dipartimento di Chimica “G. Ciamician”
- Università di Bologna
- 40126 Bologna
- Italy
| | - Fabrizia Grepioni
- Molecular Crystal Engineering Laboratory
- Dipartimento di Chimica “G. Ciamician”
- Università di Bologna
- 40126 Bologna
- Italy
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21
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Cao Y, Naseri M, He Y, Xu C, Walsh LJ, Ziora ZM. Non-antibiotic antimicrobial agents to combat biofilm-forming bacteria. J Glob Antimicrob Resist 2019; 21:445-451. [PMID: 31830536 DOI: 10.1016/j.jgar.2019.11.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 12/13/2022] Open
Abstract
Biofilms can be produced by multiple species or by a single strain of bacteria. The biofilm state enhances the resistance of the resident microorganisms to antimicrobial agents by producing extracellular polymeric substances. Typically, antibiotics are used to stop the growth of bacteria, but emerging resistance has limited their effectiveness. Bacteria in biofilms are less susceptible to antibiotics compared with their free-floating state, as biofilms impair antibiotic penetration. To obviate this challenge, non-antibiotic antimicrobial agents are needed. This review describes two classes of these agents, namely antimicrobial nanoparticles and antimicrobial peptides. Applications of these antimicrobials in the food industry and medical applications are discussed, and the directions for future research are highlighted.
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Affiliation(s)
- Yuxue Cao
- School of Chemistry and Molecular Biosciences, The University of Queensland, QLD 4072, Australia; School of Dentistry, The University of Queensland, QLD 4006, Australia
| | - Mahdi Naseri
- Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, VIC 3800, Australia
| | - Yan He
- School of Dentistry, The University of Queensland, QLD 4006, Australia; Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital and Harvard School of Dental Medicine, Boston, MA 02114, USA.
| | - Chun Xu
- School of Dentistry, The University of Queensland, QLD 4006, Australia
| | - Laurence J Walsh
- School of Dentistry, The University of Queensland, QLD 4006, Australia
| | - Zyta M Ziora
- Institute for Molecular Bioscience, The University of Queensland, QLD 4072, Australia.
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22
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Alviz-Gazitua P, Fuentes-Alburquenque S, Rojas LA, Turner RJ, Guiliani N, Seeger M. The Response of Cupriavidus metallidurans CH34 to Cadmium Involves Inhibition of the Initiation of Biofilm Formation, Decrease in Intracellular c-di-GMP Levels, and a Novel Metal Regulated Phosphodiesterase. Front Microbiol 2019; 10:1499. [PMID: 31338076 PMCID: PMC6629876 DOI: 10.3389/fmicb.2019.01499] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 06/14/2019] [Indexed: 11/21/2022] Open
Abstract
Cadmium is a highly toxic heavy metal for biological systems. Cupriavidus metallidurans CH34 is a model strain to study heavy metal resistance and bioremediation as it is able to deal with high heavy metal concentrations. Biofilm formation by bacteria is mediated by the second messenger bis-(3′–5′)-cyclic dimeric guanosine monophosphate (c-di-GMP). The aim of this study was to characterize the response of C. metallidurans CH34 planktonic and biofilm cells to cadmium including their c-di-GMP regulatory pathway. Inhibition of the initiation of biofilm formation and EPS production by C. metallidurans CH34 correlates with increased concentration of cadmium. Planktonic and biofilm cells showed similar tolerance to cadmium. During exposure to cadmium an acute decrease of c-di-GMP levels in planktonic and biofilm cells was observed. Transcription analysis by RT-qPCR showed that cadmium exposure to planktonic and biofilm cells induced the expression of the urf2 gene and the mercuric reductase encoding merA gene, which belong to the Tn501/Tn21 mer operon. After exposure to cadmium, the cadA gene involved in cadmium resistance was equally upregulated in both lifestyles. Bioinformatic analysis and complementation assays indicated that the protein encoded by the urf2 gene is a functional phosphodiesterase (PDE) involved in the c-di-GMP metabolism. We propose to rename the urf2 gene as mrp gene for metal regulated PDE. An increase of the second messenger c-di-GMP content by the heterologous expression of the constitutively active diguanylate cyclase PleD correlated with an increase in biofilm formation and cadmium susceptibility. These results indicate that the response to cadmium in C. metallidurans CH34 inhibits the initiation of biofilm lifestyle and involves a decrease in c-di-GMP levels and a novel metal regulated PDE.
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Affiliation(s)
- Pablo Alviz-Gazitua
- Laboratorio de Comunicación Bacteriana, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile.,Ph.D. Program of Microbiology, Faculty of Sciences, University of Chile, Santiago, Chile
| | - Sebastián Fuentes-Alburquenque
- Microbial Ecology of Extreme Systems Laboratory, Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago, Chile
| | - Luis A Rojas
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile.,Department of Chemistry, Universidad Catoìlica del Norte, Antofagasta, Chile
| | - Raymond J Turner
- Biofilm Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Nicolas Guiliani
- Laboratorio de Comunicación Bacteriana, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Michael Seeger
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile
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23
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Zinc Acetate Potentiates the Action of Tosufloxacin against Escherichia coli Biofilm Persisters. Antimicrob Agents Chemother 2019; 63:AAC.00069-19. [PMID: 30936108 DOI: 10.1128/aac.00069-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/28/2019] [Indexed: 01/31/2023] Open
Abstract
Formation of bacterial biofilms is a major health threat due to their high levels of tolerance to multiple antibiotics and the presence of persisters responsible for infection relapses. We previously showed that a combination of starvation and induction of SOS response in biofilm led to increased levels of persisters and biofilm tolerance to fluoroquinolones. In this study, we hypothesized that inhibition of the SOS response may be an effective strategy to target biofilms and fluoroquinolone persister cells. We tested the survival of Escherichia coli biofilms to different classes of antibiotics in starved and nonstarved conditions and in the presence of zinc acetate, a SOS response inhibitor. We showed that zinc acetate potentiates, albeit moderately, the activity of fluoroquinolones against E. coli persisters in starved biofilms. The efficacy of zinc acetate to increase fluoroquinolone activity, particularly that of tosufloxacin, suggests that such a combination may be a potential strategy for treating biofilm-related bacterial infections.
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24
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Gugala N, Vu D, Parkins MD, Turner RJ. Specificity in the Susceptibilities of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus Clinical Isolates to Six Metal Antimicrobials. Antibiotics (Basel) 2019; 8:antibiotics8020051. [PMID: 31052359 PMCID: PMC6627307 DOI: 10.3390/antibiotics8020051] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 04/18/2019] [Accepted: 04/30/2019] [Indexed: 02/06/2023] Open
Abstract
In response to the occurrence of antibiotic resistance, there has been rapid developments in the field of metal-based antimicrobials. Although it is largely assumed that metals provide broad-spectrum microbial efficacy, studies have shown that this is not always the case. Therefore, in this study, we compared the susceptibilities of 93 clinical isolates belonging to the species Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus against six metals, namely aluminum, copper, gallium, nickel, silver and zinc. To provide qualitative comparative information, the resulting zones of growth inhibition were compared to the minimal inhibitory concentrations of three indicator strains E. coli ATCC 25922, P. aeruginosa ATCC 27853 and S. aureus ATCC 25923. Here, we demonstrate that the metal efficacies were species- and isolate-specific. Only several isolates were either resistant or sensitive to all of the six metals, with great variability found between isolates. However, the greatest degree of similarity was found with the E. coli isolates. In contrast, the susceptibilities of the remaining two collections, S. aureus and P. aeruginosa, were more highly dispersed. Using this information, we have shown that metals are not equal in their efficacies. Hence, their use should be tailored against a particular microorganism and care should be taken to ensure the use of the correct concentration.
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Affiliation(s)
- Natalie Gugala
- Department of Biological Sciences, University of Calgary, Calgary T2N 1N4, Canada.
| | - Dennis Vu
- Department of Biological Sciences, University of Calgary, Calgary T2N 1N4, Canada.
| | - Michael D Parkins
- Cumming School of Medicine, University of Calgary, Calgary T2N 1N4, Canada.
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary, Calgary T2N 1N4, Canada.
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25
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Sicairos-Ruelas EE, Gerba CP, Bright KR. Efficacy of copper and silver as residual disinfectants in drinking water. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2019; 54:146-155. [PMID: 30686111 DOI: 10.1080/10934529.2018.1535160] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/02/2018] [Accepted: 10/05/2018] [Indexed: 06/09/2023]
Abstract
Contamination events and biofilms can decrease the amount of free chlorine available in drinking water systems. The efficacy of 100 μg/L silver and 400 μg/L copper, individually and combined, were evaluated as secondary, longer-lasting residual disinfectants against Salmonella enterica serovar Typhimurium, Escherichia coli, Listeria monocytogenes, and Mycobacterium fortuitum at 24 °C and 4 °C. A >5.0-log10 reduction was observed in E. coli and L. monocytogenes after three hours and S. Typhimurium following seven hours of exposure to silver. M. fortuitum was the most resistant species to silver (1.11-log10 after seven hours). Copper did not significantly reduce S. Typhimurium and E. coli at 24 °C; ≥2.80-log10 reductions were observed in the Gram-positive L. monocytogenes and M. fortuitum. Longer exposure times were required at 4 °C to achieve significant reductions in all species. A synergistic effect was observed when silver and copper were combined at 24 °C. In addition, silver was not affected by the presence of organic matter at concentrations that completely inhibited 0.2 mg/L chlorine. The results of this study suggest that combinations of silver and copper show promise as secondary residual disinfectants. They may also be used in conjunction with low chlorine levels or other disinfectants to provide additional, long-lasting residuals in distribution systems.
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Affiliation(s)
- Enue E Sicairos-Ruelas
- a Water and Energy Sustainable Technology Center , The University of Arizona , Tucson , Arizona , USA
| | - Charles P Gerba
- a Water and Energy Sustainable Technology Center , The University of Arizona , Tucson , Arizona , USA
| | - Kelly R Bright
- a Water and Energy Sustainable Technology Center , The University of Arizona , Tucson , Arizona , USA
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26
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Using a Chemical Genetic Screen to Enhance Our Understanding of the Antimicrobial Properties of Gallium against Escherichia coli. Genes (Basel) 2019; 10:genes10010034. [PMID: 30634525 PMCID: PMC6356860 DOI: 10.3390/genes10010034] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 12/17/2018] [Accepted: 01/04/2019] [Indexed: 12/13/2022] Open
Abstract
The diagnostic and therapeutic agent gallium offers multiple clinical and commercial uses including the treatment of cancer and the localization of tumors, among others. Further, this metal has been proven to be an effective antimicrobial agent against a number of microbes. Despite the latter, the fundamental mechanisms of gallium action have yet to be fully identified and understood. To further the development of this antimicrobial, it is imperative that we understand the mechanisms by which gallium interacts with cells. As a result, we screened the Escherichia coli Keio mutant collection as a means of identifying the genes that are implicated in prolonged gallium toxicity or resistance and mapped their biological processes to their respective cellular system. We discovered that the deletion of genes functioning in response to oxidative stress, DNA or iron–sulfur cluster repair, and nucleotide biosynthesis were sensitive to gallium, while Ga resistance comprised of genes involved in iron/siderophore import, amino acid biosynthesis and cell envelope maintenance. Altogether, our explanations of these findings offer further insight into the mechanisms of gallium toxicity and resistance in E. coli.
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27
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Jing H, Sahle-Demessie E, Sorial GA. Inhibition of biofilm growth on polymer-MWCNTs composites and metal surfaces. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 633:167-178. [PMID: 29573683 DOI: 10.1016/j.scitotenv.2018.03.065] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/06/2018] [Accepted: 03/06/2018] [Indexed: 06/08/2023]
Abstract
There is an increased interest in incorporating multi-wall carbon nanotubes (MWCNTs) into polymer matrices to control the adhesion of bacteria to surfaces and the subsequent formation of biofilm growth on the surface of water pipes, food packages, and medical devices. Microbial interactions with carbon nanotube-polymer composites in the environment are not well understood. The growth of Pseudomonas fluorescens (gram-negative) and Mycobacterium smegmatis (gram-positive) biofilms on copper, polyethylene (PE), polyvinyl chloride, and stainless steel was compared with growth on MWCNT-PE composites in order to gain insight into the effect of the surface properties of nanomaterials on the attachment and proliferation of microorganism which could result in the engineering of better, non-fouling materials. A statistical analysis of the biofilm growth showed a significant impact of materials for both P. fluorescens (p < 0.0001) and M. smegmatis (p = 0.00426). Biofilm growth after 56 days on PE compared to biofilm growth on copper surfaces decreased by 46.4% and 34.9% for P. fluorescens and M. smegmatis, respectively. Biofilm growth on PE-multiwall-carbon-nanotubes (MWCNTs)-composites surface compared to PE decreased by 89.3% and 29% for P. fluorescens and M. smegmatis, respectively. Bacterial species (p < 0.0006) and surface roughness (p < 0.0001) were important factors in determining the attachment and initial biofilm growth rate. The interactions between cells and material surface could be attributed to the complicated and collective effect of electrostatic forces, hydrophobic interactions, and hydrogen/covalent bonding. Further study is needed to determine whether or not there is a difference between the cell attachment in the exponential growth phase and the stationary, or decay, phase cells.
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Affiliation(s)
- Hengye Jing
- Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221, USA
| | | | - George A Sorial
- Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221, USA
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Cieplik F, Kara E, Muehler D, Enax J, Hiller KA, Maisch T, Buchalla W. Antimicrobial efficacy of alternative compounds for use in oral care toward biofilms from caries-associated bacteria in vitro. Microbiologyopen 2018; 8:e00695. [PMID: 30051653 PMCID: PMC6460264 DOI: 10.1002/mbo3.695] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/01/2018] [Accepted: 06/25/2018] [Indexed: 12/18/2022] Open
Abstract
For caries‐active patients, antimicrobial measures may be useful in addition to mechanical biofilm removal. The aim of this study was to investigate the antimicrobial efficacy of alternative compounds for use in oral care from two main categories (i.e., preservatives and natural compounds) toward biofilms from caries‐associated bacteria as compared to oral care gold‐standards chlorhexidine digluconate (CHX), cetylpyridinium chloride (CPC), and zinc. Compounds were screened in initial Streptococcus mutans biofilms. Then, the most effective compounds were further investigated in mature S. mutans and polymicrobial biofilms comprising Actinomyces naeslundii, Actinomyces odontolyticus, and S. mutans. Here, distinct treatment periods and concentrations were evaluated. Biofilms were visualized by scanning electron microscopy and bacterial membrane damage was evaluated by means of flow cytometry and staining with SYBR Green and propidium iodide. Citrus extract was the only compound exhibiting similar antimicrobial efficacy in initial S. mutans biofilms (>5 log10) as compared to CHX and CPC, but its effect was clearly inferior in mature S. mutans and polymicrobial biofilms. Flow cytometric data suggested that the mechanism of antimicrobial action of citrus extract may be based on damage of bacterial membranes similar to CHX and CPC. From all alternative compounds investigated in this study, citrus extract exhibited the highest antimicrobial efficacy toward in vitro biofilms from caries‐associated bacteria, but still was less effective than oral care gold‐standard antiseptics CHX and CPC. Nevertheless, citrus extract may be a valuable antimicrobial compound for use in oral care for caries‐active patients.
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Affiliation(s)
- Fabian Cieplik
- Department of Conservative Dentistry and Periodontology, University Medical Center Regensburg, Regensburg, Germany
| | - Esra Kara
- Department of Conservative Dentistry and Periodontology, University Medical Center Regensburg, Regensburg, Germany
| | - Denise Muehler
- Department of Conservative Dentistry and Periodontology, University Medical Center Regensburg, Regensburg, Germany
| | - Joachim Enax
- Oral Care Research Department, Dr. Kurt Wolff GmbH & Co. KG, Bielefeld, Germany
| | - Karl-Anton Hiller
- Department of Conservative Dentistry and Periodontology, University Medical Center Regensburg, Regensburg, Germany
| | - Tim Maisch
- Department of Dermatology, University Medical Center Regensburg, Regensburg, Germany
| | - Wolfgang Buchalla
- Department of Conservative Dentistry and Periodontology, University Medical Center Regensburg, Regensburg, Germany
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Gugala N, Lemire J, Chatfield-Reed K, Yan Y, Chua G, Turner RJ. Using a Chemical Genetic Screen to Enhance Our Understanding of the Antibacterial Properties of Silver. Genes (Basel) 2018; 9:E344. [PMID: 29986482 PMCID: PMC6071238 DOI: 10.3390/genes9070344] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 06/30/2018] [Accepted: 07/03/2018] [Indexed: 12/26/2022] Open
Abstract
It is essential to understand the mechanisms by which a toxicant is capable of poisoning the bacterial cell. The mechanism of action of many biocides and toxins, including numerous ubiquitous compounds, is not fully understood. For example, despite the widespread clinical and commercial use of silver (Ag), the mechanisms describing how this metal poisons bacterial cells remains incomplete. To advance our understanding surrounding the antimicrobial action of Ag, we performed a chemical genetic screen of a mutant library of Escherichia coli—the Keio collection, in order to identify Ag sensitive or resistant deletion strains. Indeed, our findings corroborate many previously established mechanisms that describe the antibacterial effects of Ag, such as the disruption of iron-sulfur clusters containing proteins and certain cellular redox enzymes. However, the data presented here demonstrates that the activity of Ag within the bacterial cell is more extensive, encompassing genes involved in cell wall maintenance, quinone metabolism and sulfur assimilation. Altogether, this study provides further insight into the antimicrobial mechanism of Ag and the physiological adaption of E. coli to this metal.
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Affiliation(s)
- Natalie Gugala
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
| | - Joe Lemire
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
| | - Kate Chatfield-Reed
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
| | - Ying Yan
- Department of Mathematics and Statistics, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
| | - Gordon Chua
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
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Silver bullets: A new lustre on an old antimicrobial agent. Biotechnol Adv 2018; 36:1391-1411. [PMID: 29847770 DOI: 10.1016/j.biotechadv.2018.05.004] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 04/26/2018] [Accepted: 05/21/2018] [Indexed: 01/19/2023]
Abstract
Silver was widely used in medicine to treat bacterial infections in the 19th and early 20th century, up until the discovery and development of the first modern antibiotics in the 1940s, which were markedly more effective. Since then, every new antibiotic introduced to the clinic has led to an associated development of drug resistance. Today, the threat of extensive bacterial resistance to antibiotics has reignited interest in alternative strategies to treat infectious diseases, with silver regaining well-deserved renewed attention. Silver ions are highly disruptive to bacterial integrity and biochemical function, with comparatively minimal toxicity to mammalian cells. This review focuses on the antimicrobial properties of silver and their use in synergistic combination therapy with traditional antibiotic drugs.
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What Healthcare Workers Should Know about Environmental Bacterial Contamination in the Intensive Care Unit. BIOMED RESEARCH INTERNATIONAL 2017; 2017:6905450. [PMID: 29214175 PMCID: PMC5682046 DOI: 10.1155/2017/6905450] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 09/07/2017] [Accepted: 09/28/2017] [Indexed: 12/21/2022]
Abstract
Intensive care unit- (ICU-) acquired infections are a major health problem worldwide. Inanimate surfaces and equipment contamination may play a role in cross-transmission of pathogens and subsequent patient colonization or infection. Bacteria contaminate inanimate surfaces and equipment of the patient zone and healthcare area, generating a reservoir of potential pathogens, including multidrug resistant species. Traditional terminal cleaning methods have limitations. Indeed patients who receive a bed from prior patient carrying bacteria are exposed to an increased risk (odds ratio 2.13, 95% confidence intervals 1.62-2.81) of being colonized and potentially infected by the same bacterial species of the previous patient. Biofilm formation, even on dry surfaces, may play a role in reducing the efficacy of terminal cleaning procedures since it enables bacteria to survive in the environment for a long period and provides increased resistance to commonly used disinfectants. No-touch methods (e.g., UV-light, hydrogen peroxide vapour) are under investigation and further studies with patient-centred outcomes are needed, before considering them the standard of terminal cleaning in ICUs. Healthcare workers should be aware of the role of environmental contamination in the ICU and consider it in the broader perspective of infection control measures and stewardship initiatives.
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Lemire JA, Kalan L, Gugala N, Bradu A, Turner RJ. Silver oxynitrate - an efficacious compound for the prevention and eradication of dual-species biofilms. BIOFOULING 2017; 33:460-469. [PMID: 28521545 DOI: 10.1080/08927014.2017.1322586] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/17/2017] [Indexed: 06/07/2023]
Abstract
Preventing and eradicating biofilms remains a challenge in clinical and industrial settings. Recently, the present authors demonstrated that silver oxynitrate (Ag7NO11) prevented and eradicated single-species planktonic and biofilm populations of numerous microbes at lower concentrations than other silver (Ag) compounds. Here, the antimicrobial and anti-biofilm efficacy of Ag7NO11 is elaborated by testing its in vitro activity against combinations of dual-species, planktonic and biofilm populations of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. As further evidence emerges that multispecies bacterial communities are more common in the environment than their single-species counterparts, this study reinforces the diverse applicability of the minimal biofilm eradication concentration (MBEC™) assay for testing antimicrobial compounds against biofilms. Furthermore, this study demonstrated that Ag7NO11 had enhanced antimicrobial and anti-biofilm activity compared to copper sulfate (CuSO4) and silver nitrate (AgNO3) against the tested bacterial species.
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Affiliation(s)
- Joe A Lemire
- a The Biofilm Research Group, Department of Biological Sciences , University of Calgary , Calgary , Canada
| | | | - Natalie Gugala
- a The Biofilm Research Group, Department of Biological Sciences , University of Calgary , Calgary , Canada
| | - Alexandru Bradu
- a The Biofilm Research Group, Department of Biological Sciences , University of Calgary , Calgary , Canada
| | - Raymond J Turner
- a The Biofilm Research Group, Department of Biological Sciences , University of Calgary , Calgary , Canada
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