1
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Bernardy C, Malley J. Impacts of Surface Characteristics and Dew Point on the Blue-Light (BL 405) Inactivation of Viruses. Microorganisms 2023; 11:2638. [PMID: 38004651 PMCID: PMC10673487 DOI: 10.3390/microorganisms11112638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/26/2023] Open
Abstract
The increased prevalence of multidrug-resistant organisms (MDROs), healthcare associated infections (HAIs), and the recent COVID-19 pandemic has caused the photoinactivation industry to explore alternative wavelengths. Blue light (BL405) has gained significant interest as it is much less harmful to the skin and eyes than traditional germicidal wavelengths; therefore, in theory, it can be used continuously with human exposure. At present, the viricidal effects of BL405 are largely unknown as the literature predominately addresses bacterial disinfection performed with this wavelength. This work provides novel findings to the industry, reporting on the virucidal effects of BL405 on surfaces. This research utilizes three surfaces: ceramic, PTFE, and stainless steel. The efficacy of BL405 inactivation varied by surface type, which was due to surface characteristics, such as the contact angle, porosity, zeta potential, and reflectivity. Additionally, the effect of the dew point on BL405 inactivation efficacy was determined. This research is the first to study the effects of the dew point on the virucidal effectiveness of BL405 surface inactivation. The effects of the dew point were significant for all surfaces and the control experiments. The high-dew-point conditions (18 °C) yielded higher levels of BL405 inactivation and viral degradation for the experiments and controls, respectively.
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Affiliation(s)
| | - James Malley
- Department of Civil and Environmental Engineering, College of Engineering & Physical Sciences, University of New Hampshire, Durham, NH 03824, USA;
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2
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Sinclair LG, Dougall LR, Ilieva Z, McKenzie K, Anderson JG, MacGregor SJ, Maclean M. Laboratory evaluation of the broad-spectrum antibacterial efficacy of a low-irradiance visible 405-nm light system for surface-simulated decontamination. HEALTH AND TECHNOLOGY 2023; 13:1-15. [PMID: 37363345 PMCID: PMC10264887 DOI: 10.1007/s12553-023-00761-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 05/30/2023] [Indexed: 06/28/2023]
Abstract
Purpose Lighting systems which use visible light blended with antimicrobial 405-nm violet-blue light have recently been developed for safe continuous decontamination of occupied healthcare environments. This paper characterises the optical output and antibacterial efficacy of a low irradiance 405-nm light system designed for environmental decontamination applications, under controlled laboratory conditions. Methods In the current study, the irradiance output of a ceiling-mounted 405-nm light source was profiled within a 3×3×2 m (18 m3) test area; with values ranging from 0.001-2.016 mWcm-2. To evaluate antibacterial efficacy of the light source for environmental surface decontamination, irradiance levels within this range (0.021-1 mWcm-2) at various angular (Δ ϴ=0-51.3) and linear (∆s=1.6-2.56 m) displacements from the source were used to generate inactivation kinetics, using the model organism, Staphylococcus aureus. Additionally, twelve bacterial species were surface-seeded and light-exposed at a fixed displacement below the source (1.5 m; 0.5 mWcm-2) to demonstrate broad-spectrum efficacy at heights typical of high touch surfaces within occupied settings. Results Results demonstrate that significant (P≤0.05) inactivation was successfully achieved at all irradiance values investigated, with spatial positioning from the source affecting inactivation, with greater times required for inactivation as irradiance decreased. Complete/near-complete (≥93.28%) inactivation of all bacteria was achieved following exposure to 0.5 mWcm-2 within exposure times realistic of those utilised practically for whole-room decontamination (2-16 h). Conclusion This study provides fundamental evidence of the efficacy, and energy efficiency, of low irradiance 405-nm light for bacterial inactivation within a controlled laboratory setting, further justifying its benefits for practical infection control applications.
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Affiliation(s)
- Lucy G Sinclair
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - Laura R Dougall
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - Zornitsa Ilieva
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK
| | - Karen McKenzie
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - John G Anderson
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - Scott J MacGregor
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - Michelle Maclean
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK
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3
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Cheng CW, Lee SY, Chen TY, Yang MJ, Yuann JMP, Chiu CM, Huang ST, Liang JY. A study of the effect of reactive oxygen species induced by violet and blue light from oxytetracycline on the deactivation of Escherichia coli. Photodiagnosis Photodyn Ther 2022; 39:102917. [PMID: 35597444 DOI: 10.1016/j.pdpdt.2022.102917] [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: 04/02/2022] [Revised: 05/07/2022] [Accepted: 05/17/2022] [Indexed: 10/18/2022]
Abstract
Oxytetracycline (OTC), a tetracycline antibiotic, is a broad-spectrum antibacterial agent. In this investigation, liquid chromatography-mass spectrometry (LC-MS) is utilized to determine the effects of blue light (λ = 448 nm) illumination (BLIA) and violet light (λ = 403 nm) illumination (VLIA) on conformational changes in OTC at pH 7.8. The photochemical effect of OTC that is exposed to BLIA and VLIA on the deactivation of Escherichia coli (E. coli) is studied. The deactivation of E. coli has an insignificant effect on treatment with OTC alone. OTC is relatively unstable under BLIA and VLIA illumination in an alkaline solution, and OTC has been shown to inactivate E. coli by generating reactive oxygen species (ROS). Less anionic superoxide radicals (O2•-) are generated from OTC that is treated with BLIA than that from VLIA treatment, so OTC is more efficient in inactivating E. coli under VLIA. Inactivation of reduction rates of 0.51 and 3.65 logs in E. coli are achieved using 0.1 mM OTC under BLIA for 120 min and VLIA for 30 min, respectively, under the same illumination intensity (20 W/m2). Two photolytic products of OTC (PPOs) are produced when OTC is exposed to BLIA and VLIA, with molecular ions at m/z 447 and 431, molecular formulae C21H22N2O9 and C21H22N2O8, and masses of 446.44 and 430.44 g/mol, respectively. The results show that when exposed to VLIA, OTC exhibits enhanced inactivation of E. coli, suggesting that the photochemical treatment of OTC is a potential supplement in a hygienic process.
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Affiliation(s)
- Chien-Wei Cheng
- Department of Biotechnology, Ming Chuan University, Gui-Shan 33343, Taiwan.
| | - Shwu-Yuan Lee
- Department of Tourism and Leisure, Hsing Wu University, New Taipei City 24452, Taiwan.
| | - Tang-Yu Chen
- Department of Biotechnology, Ming Chuan University, Gui-Shan 33343, Taiwan.
| | - Meei-Ju Yang
- Tea Research and Extension Station, Yangmei 326011, Taiwan.
| | - Jeu-Ming P Yuann
- Department of Biotechnology, Ming Chuan University, Gui-Shan 33343, Taiwan
| | - Chi-Ming Chiu
- Department of Biotechnology, Ming Chuan University, Gui-Shan 33343, Taiwan.
| | - Shiuh-Tsuen Huang
- Department of Science Education and Application, National Taichung University of Education, Taichung 40306, Taiwan; Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung 40200, Taiwan.
| | - Ji-Yuan Liang
- Department of Biotechnology, Ming Chuan University, Gui-Shan 33343, Taiwan.
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4
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Wang S, Wong KI, Li Y, Ishii M, Li X, Wei L, Lu M, Wu MX. Blue light potentiates safety and bactericidal activity of p-Toluquinone. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2022; 230:112427. [PMID: 35338920 DOI: 10.1016/j.jphotobiol.2022.112427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 02/04/2022] [Accepted: 03/15/2022] [Indexed: 06/14/2023]
Abstract
Fewer antibiotics are available for effective management of bacterial infections to date owing to increasing multiple-drug resistance (MDR). Here, we expand our early success in combination of 405 nm blue light irradiation with phenolic compounds to sufficiently kill blue light-refractory MDR Escherichia coli (E. coli). p-Toluquinone (p-TQ) alongside blue light inactivated 7.3 log10E. coli within 6 min, whereas either alone was totally ineffective. A similar killing efficacy was attained with four other pathogens commonly seen in hospital-acquired infections and Enterococcus faecalis (Ef) that don't produce porphyrins-like molecules. The combinatory therapy prevented recurrence of E. coli infection in skin scratch wounds of murine. The bactericidal activity was ascribed to reactive oxygen species (ROS) generation triggered by blue light-mediated excitation of p-TQ, which is less likely to induce resistance because of multi-targeted and non-specific nature of ROS. Remarkably, toxic p-TQ became harmless to mammalian cells after brief exposure to blue light while retaining its bactericidal activity. The opposite effect of blue light on p-TQ activity unravels a novel, simple strategy to detoxify p-TQ and its combination with blue light as a safe and efficacious bactericidal modality for managing MDR bacterial infections.
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Affiliation(s)
- Shen Wang
- Wellman Center for Photomedicine, Massachusetts General Hospital, Department of Dermatology, Harvard Medical School, 50 Blossom Street, Boston, MA 02114, USA; Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ka Ioi Wong
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yongli Li
- Wellman Center for Photomedicine, Massachusetts General Hospital, Department of Dermatology, Harvard Medical School, 50 Blossom Street, Boston, MA 02114, USA
| | - Momoko Ishii
- Wellman Center for Photomedicine, Massachusetts General Hospital, Department of Dermatology, Harvard Medical School, 50 Blossom Street, Boston, MA 02114, USA
| | - Xin Li
- Instrumental Analysis Center, Shanghai Jiao Tong University, Shanghai, China
| | - Li Wei
- Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Min Lu
- Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
| | - Mei X Wu
- Wellman Center for Photomedicine, Massachusetts General Hospital, Department of Dermatology, Harvard Medical School, 50 Blossom Street, Boston, MA 02114, USA.
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5
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Abstract
The COVID-19 pandemic is driving the search for new antiviral techniques. Bacteria and fungi are known to be inactivated not only by ultraviolet radiation but also by visible light. Several studies have recently appeared on this subject, in which viruses were mainly irradiated in media. However, it is an open question to what extent the applied media, and especially their riboflavin concentration, can influence the results. A literature search identified appropriate virus photoinactivation publications and, where possible, viral light susceptibility was quantitatively determined in terms of average log-reduction doses. Sensitivities of enveloped viruses were plotted against assumed riboflavin concentrations. Viruses appear to be sensitive to visible (violet/blue) light. The median log-reduction doses of all virus experiments performed in liquids is 58 J/cm2. For the non-enveloped, enveloped and coronaviruses only, they were 222, 29 and 19 J/cm2, respectively. Data are scarce, but it appears that (among other things) the riboflavin concentration in the medium has an influence on the log-reduction doses. Experiments with DMEM, with its 0.4 mg/L riboflavin, have so far produced results with the greatest viral susceptibilities. It should be critically evaluated whether the currently published virus sensitivities are really only intrinsic properties of the virus, or whether the medium played a significant role. In future experiments, irradiation should be carried out in solutions with the lowest possible riboflavin concentration.
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6
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SHIRAI AKIHIRO, YASUTOMO YUKO, KANNO YUKA. Effects of Violet-Blue Light-Emitting Diode on Controlling Bacterial Contamination in Boiled Young Sardine. Biocontrol Sci 2022; 27:9-19. [DOI: 10.4265/bio.27.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- AKIHIRO SHIRAI
- Department of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University
| | - YU-KO YASUTOMO
- Department of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University
| | - YUKA KANNO
- Department of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University
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7
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Bauer R, Hoenes K, Meurle T, Hessling M, Spellerberg B. The effects of violet and blue light irradiation on ESKAPE pathogens and human cells in presence of cell culture media. Sci Rep 2021; 11:24473. [PMID: 34963696 PMCID: PMC8714816 DOI: 10.1038/s41598-021-04202-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 12/16/2021] [Indexed: 12/18/2022] Open
Abstract
Bacteria belonging to the group of ESKAPE pathogens are responsible for the majority of nosocomial infections. Due to the increase of antibiotic resistance, alternative treatment strategies are of high clinical relevance. In this context visible light as disinfection technique represents an interesting option as microbial pathogens can be inactivated without adjuvants. However cytotoxic effects of visible light on host cells have also been reported. We compared the cytotoxicity of violet and blue light irradiation on monocytic THP-1 and alveolar epithelium A549 cells with the inactivation effect on ESKAPE pathogens. THP-1 cells displayed a higher susceptibility to irradiation than A549 cells with first cytotoxic effects occurring at 300 J cm−2 (405 nm) and 400 J cm−2 (450 nm) in comparison to 300 J cm−2 and 1000 J cm−2, respectively. We could define conditions in which a significant reduction of colony forming units for all ESKAPE pathogens, except Enterococcus faecium, was achieved at 405 nm while avoiding cytotoxicity. Irradiation at 450 nm demonstrated a more variable effect which was species and medium dependent. In summary a significant reduction of viable bacteria could be achieved at subtoxic irradiation doses, supporting a potential use of visible light as an antimicrobial agent in clinical settings.
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Affiliation(s)
- Richard Bauer
- Institute of Medical Microbiology and Hygiene, University Hospital Ulm, 89081, Ulm, Germany
| | - Katharina Hoenes
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, 89081, Ulm, Germany
| | - Tobias Meurle
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, 89081, Ulm, Germany
| | - Martin Hessling
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, 89081, Ulm, Germany
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, University Hospital Ulm, 89081, Ulm, Germany.
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8
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Vatter P, Hoenes K, Hessling M. Blue light inactivation of the enveloped RNA virus Phi6. BMC Res Notes 2021; 14:187. [PMID: 34001258 PMCID: PMC8128082 DOI: 10.1186/s13104-021-05602-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 05/06/2021] [Indexed: 11/10/2022] Open
Abstract
Objective Ultraviolet radiation is known for its antimicrobial properties but unfortunately, it could also harm humans. Currently, disinfection techniques against SARS-CoV-2 are being sought that can be applied on air and surfaces and which do not pose a relevant thread to humans. In this study, the bacteriophage phi6, which like SARS-CoV-2 is an enveloped RNA virus, is irradiated with visible blue light at a wavelength of 455 nm. Results For the first time worldwide, the antiviral properties of blue light around 455 nm can be demonstrated. With a dose of 7200 J/cm2, the concentration of this enveloped RNA virus can be successfully reduced by more than three orders of magnitude. The inactivation mechanism is still unknown, but the sensitivity ratio of phi6 towards blue and violet light hints towards an involvement of photosensitizers of the host cells. Own studies on coronaviruses cannot be executed, but the results support speculations about blue-susceptibility of coronaviruses, which might allow to employ blue light for infection prevention or even therapeutic applications.
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Affiliation(s)
- Petra Vatter
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany
| | - Katharina Hoenes
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany
| | - Martin Hessling
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany.
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9
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Hessling M, Wenzel U, Meurle T, Spellerberg B, Hönes K. Photoinactivation results of Enterococcus moraviensis with blue and violet light suggest the involvement of an unconsidered photosensitizer. Biochem Biophys Res Commun 2020; 533:813-817. [PMID: 32993958 DOI: 10.1016/j.bbrc.2020.09.091] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 09/21/2020] [Indexed: 12/23/2022]
Abstract
Microorganisms can be photoinactivated with 405 and 450 nm irradiation, due to endogenous photosensitizers, which absorb light of these wavelengths and generate reactive oxygen species that destroy the cells from within. The photosensitizers assumed to be responsible are porphyrins in the spectral region around 405 nm and flavins at about 450 nm. The aim of this study was to investigate this hypothesis on enterococci, considering that they do not contain porphyrins. In photoinactivation experiments with Enterococcus moraviensis, 405 nm and 450 nm irradiation both led to a reduction of the bacterial concentration by several orders of magnitude with 405 nm irradiation being much more efficient. The measurement and analysis of the fluorescence spectra revealed no signs of porphyrins whereas flavins seemed to be rapidly converted to lumichrome by 405 nm radiation. Therefore, probably none of the usual suspects, porphyrins and flavins, was responsible for the photoinactivation of Enterococcus moraviensis during 405 nm irradiation. Fluorescence experiments revealed the spectra of lumichrome and NADH, which are both known photosensitizers. Presumably, one of them or both were actually involved here. As NADH and flavins (and therefore their photodegradation product lumichrome) are abundant in all microorganisms, they are probably also involved in 405 nm photoinactivation processes of other species.
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Affiliation(s)
- Martin Hessling
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, 89081, Germany.
| | - Ulla Wenzel
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, 89081, Germany
| | - Tobias Meurle
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, 89081, Germany
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, University Hospital Ulm, Ulm, 89081, Germany
| | - Katharina Hönes
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, 89081, Germany
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10
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Sicks B, Hönes K, Spellerberg B, Hessling M. Blue LEDs in Endotracheal Tubes May Prevent Ventilator-Associated Pneumonia. PHOTOBIOMODULATION PHOTOMEDICINE AND LASER SURGERY 2020. [DOI: 10.1089/photob.2020.4842] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Ben Sicks
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany
| | - Katharina Hönes
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, University Hospital Ulm, Ulm, Germany
| | - Martin Hessling
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany
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11
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Maclean M, Gelderman MP, Kulkarni S, Tomb RM, Stewart CF, Anderson JG, MacGregor SJ, Atreya CD. Non-ionizing 405 nm Light as a Potential Bactericidal Technology for Platelet Safety: Evaluation of in vitro Bacterial Inactivation and in vivo Platelet Recovery in Severe Combined Immunodeficient Mice. Front Med (Lausanne) 2020; 6:331. [PMID: 32010702 PMCID: PMC6974518 DOI: 10.3389/fmed.2019.00331] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/20/2019] [Indexed: 01/18/2023] Open
Abstract
Bacterial contamination of ex vivo stored platelets is a cause of transfusion-transmitted infection. Violet-blue 405 nm light has recently demonstrated efficacy in reducing the bacterial burden in blood plasma, and its operational benefits such as non-ionizing nature, penetrability, and non-requirement for photosensitizing agents, provide a unique opportunity to develop this treatment for in situ treatment of ex vivo stored platelets as a tool for bacterial reduction. Sealed bags of platelet concentrates, seeded with low-level Staphylococcus aureus contamination, were 405 nm light-treated (3–10 mWcm−2) up to 8 h. Antimicrobial efficacy and dose efficiency was evaluated by quantification of the post-treatment surviving bacterial contamination levels. Platelets treated with 10 mWcm−2 for 8 h were further evaluated for survival and recovery in severe combined immunodeficient (SCID) mice. Significant inactivation of bacteria in platelet concentrates was achieved using all irradiance levels, with 99.6–100% inactivation achieved by 8 h (P < 0.05). Analysis of applied dose demonstrated that lower irradiance levels generally resulted in significant decontamination at lower doses: 180 Jcm−2/10 mWcm−2 (P = 0.008) compared to 43.2 Jcm−2/3 mWcm−2 (P = 0.002). Additionally, the recovery of light-treated platelets, compared to non-treated platelets, in the murine model showed no significant differences (P = >0.05). This report paves the way for further comprehensive studies to test 405 nm light treatment as a bactericidal technology for stored platelets.
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Affiliation(s)
- Michelle Maclean
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, United Kingdom.,Department of Biomedical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Monique P Gelderman
- Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, United States
| | - Sandhya Kulkarni
- Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, United States
| | - Rachael M Tomb
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Caitlin F Stewart
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - John G Anderson
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Scott J MacGregor
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Chintamani D Atreya
- Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, United States
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12
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Dos Anjos C, Sellera FP, de Freitas LM, Gargano RG, Telles EO, Freitas RO, Baptista MS, Ribeiro MS, Lincopan N, Pogliani FC, Sabino CP. Inactivation of milk-borne pathogens by blue light exposure. J Dairy Sci 2019; 103:1261-1268. [PMID: 31759598 DOI: 10.3168/jds.2019-16758] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 08/05/2019] [Indexed: 11/19/2022]
Abstract
Food safety and quality management play a pivotal role in the dairy industry. Milk is a highly nutritious food that also provides an excellent medium for growth of pathogenic microorganisms. Thus, dairy industry focuses most of their processes and costs on keeping contamination levels as low as possible. Thermal processes for microbial decontamination may be effective; however, they cannot provide excellent organoleptic, nutritional, and decontamination properties simultaneously. In this scenario, microbial inactivation by exposure to blue light is a promising alternative method in the food industry due to its intrinsic antimicrobial properties free of any thermal effect. Therefore, this study aimed to determine the inactivation kinetics induced by blue light (λ = 413 nm) against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhimurium, and Mycobacterium fortuitum cells suspended in whole milk or saline solution. We also performed a series of optic spectroscopies to investigate possible degradation of milk components. All species were sensitive to photoinactivation suspended either in saline solution or milk. Inactivation kinetics differs significantly depending on the suspension medium and each species is differently affected. All bacterial species tested presented more than 5 log10 of inactivation within less than 2 h of irradiation (720 J/cm2). Infrared spectroscopy did not reveal any significant alteration in any of the milk constituents (e.g., sugars, proteins, and lipids). Riboflavin (vitamin B2) was the only significantly degraded constituent found. Therefore, we conclude that microbial inactivation performed by blue light presents extraordinary potential for processes in the dairy industry.
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Affiliation(s)
- C Dos Anjos
- Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil, 05508-270
| | - F P Sellera
- Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil, 05508-270
| | - L M de Freitas
- Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo, SP, Brazil, 05513-970
| | - R G Gargano
- Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil, 05508-270
| | - E O Telles
- Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil, 05508-270
| | - R O Freitas
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, 13083-970, Campinas, SP, Brazil
| | - M S Baptista
- Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo, SP, Brazil, 05513-970
| | - M S Ribeiro
- Center for Lasers and Applications, Nuclear and Energy Research Institute, Sao Paulo, SP, Brazil, 05508-000
| | - N Lincopan
- Department of Clinical and Toxicological Analysis, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil, 05508-000; Department of Microbiology, Institute for Biomedical Sciences, University of Sao Paulo, São Paulo, SP, Brazil, 05508-000
| | - F C Pogliani
- Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil, 05508-270
| | - C P Sabino
- Department of Clinical and Toxicological Analysis, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil, 05508-000; BioLambda, Scientific and Commercial Ltd., Sao Paulo, SP, Brazil, 05360-030.
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13
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Hoenes K, Wenzel U, Spellerberg B, Hessling M. Photoinactivation Sensitivity of
Staphylococcus carnosus
to Visible‐light Irradiation as a Function of Wavelength. Photochem Photobiol 2019; 96:156-169. [DOI: 10.1111/php.13168] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/16/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Katharina Hoenes
- Institute of Medical Engineering and Mechatronics Ulm University of Applied Sciences Ulm Germany
| | - Ulla Wenzel
- Institute of Medical Engineering and Mechatronics Ulm University of Applied Sciences Ulm Germany
| | | | - Martin Hessling
- Institute of Medical Engineering and Mechatronics Ulm University of Applied Sciences Ulm Germany
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Antimicrobial Effect of Visible Light-Photoinactivation of Legionella rubrilucens by Irradiation at 450, 470, and 620 nm. Antibiotics (Basel) 2019; 8:antibiotics8040187. [PMID: 31618994 PMCID: PMC6963517 DOI: 10.3390/antibiotics8040187] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/11/2019] [Accepted: 10/13/2019] [Indexed: 01/12/2023] Open
Abstract
Despite the high number of legionella infections, there are currently no convincing preventive measures. Photoinactivation with visible light is a promising new approach and the photoinactivation sensitivity properties of planktonic Legionella rubrilucens to 450, 470, and 620 nm irradiation were thus investigated and compared to existing 405 nm inactivation data for obtaining information on responsible endogenous photosensitizers. Legionella were streaked on agar plates and irradiated with different doses by light emitting diodes (LEDs) of different visible wavelengths. When irradiating bacterial samples with blue light of 450 nm, a 5-log reduction could be achieved by applying a dose of 300 J cm−2, whereas at 470 nm, a comparable reduction required about 500 J cm−2. For red irradiation at 620 nm, no inactivation could be observed, even at 500 J cm−2. The declining photoinactivation sensitivity with an increasing wavelength is consistent with the assumption of porphyrins and flavins being among the relevant photosensitizers. These results were obtained for L. rubrilucens, but there is reason to believe that its inactivation behavior is similar to that of pathogenic legionella species. Therefore, this photoinactivation might lead to new future concepts for legionella reduction and prevention in technical applications or even on or inside the human body.
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Santhakumar K, Viswanath V. Novel Methods for Efficacy Testing of Disinfectants – Part I. TENSIDE SURFACT DET 2019. [DOI: 10.3139/113.110597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Abstract
The pathogens which are the effective transmitters of various infections pose a serious problem in restraining their interference in maintaining a sterile environment. The practical applicability of traditional methods of disinfection is restricted due to their cumbersomeness, toxic product generation, and cost-effectiveness. Therefore, the objective of the current review is to elaborate the efficacies and limitations of various novel disinfectants that can show their activity in a few minutes of treatment. The expected outcome would be feasibility for selection of a favorable disinfectant through various technologies that can generate uniform results and form a basis for the true estimation required parameters. Hence, the current paper ends with the consideration of unique new techniques that distinguishes their simplicity, safety, and efficacy in generating a sterile environment.
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Affiliation(s)
| | - Valikala Viswanath
- Carbon dioxide Research and Green Technologies Center , VIT University, Tamil Nadu , India
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Tomb RM, White TA, Coia JE, Anderson JG, MacGregor SJ, Maclean M. Review of the Comparative Susceptibility of Microbial Species to Photoinactivation Using 380-480 nm Violet-Blue Light. Photochem Photobiol 2018; 94:445-458. [DOI: 10.1111/php.12883] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 12/08/2017] [Indexed: 12/24/2022]
Affiliation(s)
- Rachael M. Tomb
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST); Department of Electronic & Electrical Engineering; University of Strathclyde; Glasgow UK
| | - Tracy A. White
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST); Department of Electronic & Electrical Engineering; University of Strathclyde; Glasgow UK
| | - John E. Coia
- Department of Clinical Microbiology; Glasgow Royal Infirmary; Glasgow UK
| | - John G. Anderson
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST); Department of Electronic & Electrical Engineering; University of Strathclyde; Glasgow UK
| | - Scott J. MacGregor
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST); Department of Electronic & Electrical Engineering; University of Strathclyde; Glasgow UK
| | - Michelle Maclean
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST); Department of Electronic & Electrical Engineering; University of Strathclyde; Glasgow UK
- Department of Biomedical Engineering; University of Strathclyde; Glasgow UK
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17
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Ahmed I, Fang Y, Lu M, Yan Q, Kamel AEHM, Hamblin MR, Dai T. Recent Patents on Light-Based Anti-Infective Approaches. RECENT PATENTS ON ANTI-INFECTIVE DRUG DISCOVERY 2018; 13:70-88. [PMID: 29119936 PMCID: PMC5938159 DOI: 10.2174/1872213x11666171108104104] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 10/17/2017] [Accepted: 10/29/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND Antibiotic resistance is one of the most serious health threats to modern medicine. The lack of potent antibiotics puts us at a disadvantage in the fight against infectious diseases, especially those caused by antibiotic-resistant microbial strains. To this end, an urgent need to search for alternative antimicrobial approaches has arisen. In the last decade, light-based anti-infective therapy has made significant strides in this fight to combat antibiotic resistance among various microbial strains. This method includes utilizing antimicrobial blue light, antimicrobial photodynamic therapy, and germicidal ultraviolet irradiation, among others. Light-based therapy is advantageous over traditional antibiotics in that it eradicates microbial cells rapidly and the likelihood of light-resistance development by microbes is low. METHODS This review highlights the patents on light-based therapy that were filed approximately within the last decade and are dedicated to eradicating pathogenic microorganisms. The primary database that was used for the search was Google Patents. The searches were performed using the keywords including blue light, antimicrobial photodynamic therapy, ultraviolet irradiation, antibiotic resistance, disinfection, bacterium, fungus, and virus. RESULTS Forty-five patents were obtained in our search: 9 patents for the antimicrobial blue light approach, 21 for antimicrobial photodynamic therapy, 11 for UV irradiation, and lastly 4 for other light-based anti-infective approaches. The treatments and devices discussed in this review are interestingly enough able to be used in various different functions and settings, such as dental applications, certain eye diseases, skin and hard surface cleansing, decontamination of internal organs (e.g., the stomach), decontamination of apparel and equipment, eradication of pathogenic microorganisms from buildings and rooms, etc. Most of the devices and inventions introduce methods of destroying pathogenic bacteria and fungi without harming human cells and tissues. CONCLUSIONS Light-based antimicrobial approaches hold great promise for the future in regards to treating antibiotic-resistant infections and related diseases.
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Affiliation(s)
- Imran Ahmed
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Yanyan Fang
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Min Lu
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Quan Yan
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Ophthalmology, Shanghai First People’s Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Ahmed El-Hussein Mohamed Kamel
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Biotechnology, National Institute of Laser Enhanced Science, Cairo University, Cairo, Egypt
| | - Michael R. Hamblin
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Tianhong Dai
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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18
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Zhao Y, Zhang X, Li Z, Huo S, Zhang K, Gao J, Wang H, Liang XJ. Spatiotemporally Controllable Peptide-Based Nanoassembly in Single Living Cells for a Biological Self-Portrait. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017. [PMID: 28639395 DOI: 10.1002/adma.201601128] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Simultaneous precise localization and activity evaluation of a biomolecule in a single living cell is through an enzyme-specific signal-amplification process, which involves the localized, site-specific self-assembly, and activation of a presignaling molecule. The inactive presignaling tetraphenylethylene (TPE)-peptide derivative, TPE-YpYY, is nondetectable and highly biocompatible and these small molecules rapidly diffuse into living cells. Upon safely arriving at an active site, and accessing the catalytic pocket of an enzyme, TPE-YpYY immediately and quantitatively accumulates in situ in response to enzymatic activity, forms an enzyme anchor TPE-YYY nanoassembly, displays aggregation-induced emission behavior, and finally lights up the active enzyme, indicating its activity, and allowing its status in living cells to be tracked. This simple and direct self-portrait method can be used to monitor dynamic self-assembly processes in individual living cells and may provide new insights that reveal undiscovered biological processes and that aid in developing biomedical hybrid devices. In the future, this strategy of molecular design can be further expanded to the noninvasive investigation of other bioactive molecules, thus facilitating quantitative imaging.
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Affiliation(s)
- Yuanyuan Zhao
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology (NCNST), Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Xu Zhang
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology (NCNST), Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
- Bioinformatics Division and Center for Synthetic and Systems Biology, TNLIST, Department of Automation, Tsinghua University, Beijing, 100084, P. R. China
| | - Zhipeng Li
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology (NCNST), Beijing, 100190, P. R. China
| | - Shuaidong Huo
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology (NCNST), Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Ke Zhang
- College of Chemistry and Molecular Engineering, Zhengzhou University, 100 Kexue Road, Zhengzhou, 450001, P. R. China
| | - Juntao Gao
- Bioinformatics Division and Center for Synthetic and Systems Biology, TNLIST, Department of Automation, Tsinghua University, Beijing, 100084, P. R. China
| | - Hao Wang
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology (NCNST), Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Xing-Jie Liang
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology (NCNST), Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
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19
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Wong TW, Cheng CW, Hsieh ZJ, Liang JY. Effects of blue or violet light on the inactivation of Staphylococcus aureus by riboflavin-5'-phosphate photolysis. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2017; 173:672-680. [PMID: 28715781 DOI: 10.1016/j.jphotobiol.2017.07.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 06/11/2017] [Accepted: 07/10/2017] [Indexed: 10/19/2022]
Abstract
The light sensitive compound riboflavin-5'-phosphate (or flavin mononucleotide, FMN) generates reactive oxygen species (ROS) upon photo-irradiation. FMN is required by all flavoproteins because it is a cofactor of biological blue-light receptors. The photochemical effects of FMN after irradiation by blue or violet light on the inactivation of Staphylococcus aureus strains, including a methicillin-resistant strain (MRSA), were investigated in this study. Upon blue- or violet-light photo-treatment, FMN was shown to inactivate S. aureus due to the generated ROS. Effective bacterial inactivation can be achieved by FMN photolysis without an exogenous electron provider. Inactivation rates of 94.9 and 95.2% in S. aureus and MRSA, respectively, can be reached by blue light irradiation (2.0mW/cm2) with 120μM FMN for 120min. A lower FMN concentration and a shorter time are required to reach similar effects by violet light irradiation. Inactivation rates of 96.3 and 97.0% in S. aureus and MRSA, respectively, can be reached by violet light irradiation (1.0mW/cm2) with 30μM FMN for 30min. The sensitivity of the inherent photosensitizers is lower under blue-light irradiation. A long exposure photolytic treatment of FMN by blue light is required to inactivate S. aureus. Violet light was found to be more efficient in S. aureus inactivation at the same radiant intensity. FMN photolysis with blue or violet light irradiation enhanced the inactivation rates of S. aureus and MRSA. FMN photochemical treatment could be a supplemental technique in hygienic decontamination processes.
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Affiliation(s)
- Tak-Wah Wong
- Department of Dermatology, Department of Biochemistry and Molecular Biology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan
| | - Chien-Wei Cheng
- Department of Biotechnology, Ming-Chuan University, Taoyüan 33343, Taiwan
| | - Zong-Jhe Hsieh
- Department of Biotechnology, Ming-Chuan University, Taoyüan 33343, Taiwan
| | - Ji-Yuan Liang
- Department of Biotechnology, Ming-Chuan University, Taoyüan 33343, Taiwan.
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20
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Hessling M, Spellerberg B, Hoenes K. Photoinactivation of bacteria by endogenous photosensitizers and exposure to visible light of different wavelengths - a review on existing data. FEMS Microbiol Lett 2016; 364:fnw270. [PMID: 27915252 DOI: 10.1093/femsle/fnw270] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 10/29/2016] [Accepted: 11/25/2016] [Indexed: 12/31/2022] Open
Abstract
Visible light has strong disinfectant properties, a fact that is not well known in comparison to the antibacterial properties of UV light. This review compiles the published data on bacterial inactivation caused by visible light and endogenous photosensitizers. It evaluates more than 50 published studies containing information on about 40 different bacterial species irradiated within the spectral range from 380 to 780 nm. In the available data a high variability of photoinactivation sensitivity is observed, which may be caused by undefined illumination conditions. Under aerobic conditions almost all bacteria except spores should be reduced by at least three log-levels with a dose of about 500 J cm-2 of 405 nm irradiation, including both Gram-positive as well as Gram-negative microorganisms. Irradiation of 470 nm is also appropriate for photoinactivating all bacteria species investigated so far but compared to 405 nm illumination it is less effective by a factor between 2 and 5. The spectral dependence of the observed photoinactivation sensitivities gives reason to the assumption that a so far unknown photosensitizer may be involved at 470 nm photoinactivation.
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Affiliation(s)
- M Hessling
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany
| | - B Spellerberg
- Institute of Medical Microbiology and Hygiene, University of Ulm, Ulm, Germany
| | - K Hoenes
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany
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21
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Gillespie JB, Maclean M, Given MJ, Wilson MP, Judd MD, Timoshkin IV, MacGregor SJ. Efficacy of Pulsed 405-nm Light-Emitting Diodes for Antimicrobial Photodynamic Inactivation: Effects of Intensity, Frequency, and Duty Cycle. Photomed Laser Surg 2016; 35:150-156. [PMID: 27759498 PMCID: PMC5346950 DOI: 10.1089/pho.2016.4179] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Objective: This study investigates possible advantages in pulsed over continuous 405-nm light-emitting diode (LED) light for bacterial inactivation and energy efficiency. Background: Alternative nonantibiotic methods of disinfection and infection control have become of significant interest. Recent studies have demonstrated the application of systems using 405-nm LEDs for continuous disinfection of the clinical environment, and also for potential treatment of contaminated wounds. Methods: Liquid suspensions of 103 colony-forming units/mL populations of Staphylococcus aureus were subject to pulsed 405-nm light of different frequencies, duty cycles, and intensities and for different lengths of time. Results: Pulsed exposures with the same average irradiance of 16 mW/cm2 and varying duty cycle (25%, 50%, 75%) showed very similar performance compared with continuous exposures, with 95–98% reduction of S. aureus achieved for all duty cycles. The pulsing frequency was varied in intervals from 100 Hz to 10 kHz and appeared to have little effect on antimicrobial efficacy. However, when comparing pulsed with continuous exposure, an improvement in inactivation per unit optical energy was achieved, with results showing an increase of approximately 83% in optical efficiency. Conclusions: These results suggest that under pulsed conditions, a lower energy consumption and lower perceived brightness could be achieved, thus potentially providing improved operating conditions for medical/infection control applications without compromising antimicrobial efficacy.
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Affiliation(s)
- Jonathan B Gillespie
- 1 Department of Electronic & Electrical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Michelle Maclean
- 1 Department of Electronic & Electrical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom .,2 Department of Biomedical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Martin J Given
- 3 Department of Electronic & Electrical Engineering, High Voltage Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Mark P Wilson
- 3 Department of Electronic & Electrical Engineering, High Voltage Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Martin D Judd
- 3 Department of Electronic & Electrical Engineering, High Voltage Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Igor V Timoshkin
- 1 Department of Electronic & Electrical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom .,3 Department of Electronic & Electrical Engineering, High Voltage Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Scott J MacGregor
- 1 Department of Electronic & Electrical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom .,3 Department of Electronic & Electrical Engineering, High Voltage Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
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A New Proof of Concept in Bacterial Reduction: Antimicrobial Action of Violet-Blue Light (405 nm) in Ex Vivo Stored Plasma. JOURNAL OF BLOOD TRANSFUSION 2016; 2016:2920514. [PMID: 27774337 PMCID: PMC5059568 DOI: 10.1155/2016/2920514] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 08/28/2016] [Indexed: 11/17/2022]
Abstract
Bacterial contamination of injectable stored biological fluids such as blood plasma and platelet concentrates preserved in plasma at room temperature is a major health risk. Current pathogen reduction technologies (PRT) rely on the use of chemicals and/or ultraviolet light, which affects product quality and can be associated with adverse events in recipients. 405 nm violet-blue light is antibacterial without the use of photosensitizers and can be applied at levels safe for human exposure, making it of potential interest for decontamination of biological fluids such as plasma. As a pilot study to test whether 405 nm light is capable of inactivating bacteria in biological fluids, rabbit plasma and human plasma were seeded with bacteria and treated with a 405 nm light emitting diode (LED) exposure system (patent pending). Inactivation was achieved in all tested samples, ranging from low volumes to prebagged plasma. 99.9% reduction of low density bacterial populations (≤103 CFU mL−1), selected to represent typical “natural” contamination levels, was achieved using doses of 144 Jcm−2. The penetrability of 405 nm light, permitting decontamination of prebagged plasma, and the nonrequirement for photosensitizing agents provide a new proof of concept in bacterial reduction in biological fluids, especially injectable fluids relevant to transfusion medicine.
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23
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Ramakrishnan P, Maclean M, MacGregor SJ, Anderson JG, Grant MH. Cytotoxic responses to 405nm light exposure in mammalian and bacterial cells: Involvement of reactive oxygen species. Toxicol In Vitro 2016; 33:54-62. [PMID: 26916085 DOI: 10.1016/j.tiv.2016.02.011] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 02/12/2016] [Accepted: 02/17/2016] [Indexed: 02/07/2023]
Abstract
Light at wavelength 405 nm is an effective bactericide. Previous studies showed that exposing mammalian cells to 405 nm light at 36 J/cm(2) (a bactericidal dose) had no significant effect on normal cell function, although at higher doses (54 J/cm(2)), mammalian cell death became evident. This research demonstrates that mammalian and bacterial cell toxicity induced by 405 nm light exposure is accompanied by reactive oxygen species production, as detected by generation of fluorescence from 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate. As indicators of the resulting oxidative stress in mammalian cells, a decrease in intracellular reduced glutathione content and a corresponding increase in the efflux of oxidised glutathione were observed from 405 nm light treated cells. The mammalian cells were significantly protected from dying at 54 J/cm(2) in the presence of catalase, which detoxifies H2O2. Bacterial cells were significantly protected by sodium pyruvate (H2O2 scavenger) and by a combination of free radical scavengers (sodium pyruvate, dimethyl thiourea (OH scavenger) and catalase) at 162 and 324 J/cm(2). Results therefore suggested that the cytotoxic mechanism of 405 nm light in mammalian cells and bacteria could be oxidative stress involving predominantly H2O2 generation, with other ROS contributing to the damage.
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Affiliation(s)
- Praveen Ramakrishnan
- University of Strathclyde, Department of Biomedical Engineering, Wolfson Centre, 106 Rottenrow, Glasgow, Scotland G4 0NW, United Kingdom
| | - Michelle Maclean
- University of Strathclyde, Department of Biomedical Engineering, Wolfson Centre, 106 Rottenrow, Glasgow, Scotland G4 0NW, United Kingdom; University of Strathclyde, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, 204 George street, Glasgow, Scotland G1 1XW, United Kingdom
| | - Scott J MacGregor
- University of Strathclyde, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, 204 George street, Glasgow, Scotland G1 1XW, United Kingdom
| | - John G Anderson
- University of Strathclyde, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, 204 George street, Glasgow, Scotland G1 1XW, United Kingdom
| | - M Helen Grant
- University of Strathclyde, Department of Biomedical Engineering, Wolfson Centre, 106 Rottenrow, Glasgow, Scotland G4 0NW, United Kingdom.
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Synergistic efficacy of 405 nm light and chlorinated disinfectants for the enhanced decontamination of Clostridium difficile spores. Anaerobe 2015; 37:72-7. [PMID: 26708703 DOI: 10.1016/j.anaerobe.2015.12.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 12/13/2015] [Indexed: 01/05/2023]
Abstract
The ability of Clostridium difficile to form highly resilient spores which can survive in the environment for prolonged periods causes major contamination problems. Antimicrobial 405 nm light is being developed for environmental decontamination within hospitals, however further information relating to its sporicidal efficacy is required. This study aims to establish the efficacy of 405 nm light for inactivation of C. difficile vegetative cells and spores, and to establish whether spore susceptibility can be enhanced by the combined use of 405 nm light with low concentration chlorinated disinfectants. Vegetative cells and spore suspensions were exposed to increasing doses of 405 nm light (at 70-225 mW/cm(2)) to establish sensitivity. A 99.9% reduction in vegetative cell population was demonstrated with a dose of 252 J/cm(2), however spores demonstrated higher resilience, with a 10-fold increase in required dose. Exposures were repeated with spores suspended in the hospital disinfectants sodium hypochlorite, Actichlor and Tristel at non-lethal concentrations (0.1%, 0.001% and 0.0001%, respectively). Enhanced sporicidal activity was achieved when spores were exposed to 405 nm light in the presence of the disinfectants, with a 99.9% reduction achieved following exposure to 33% less light dose than required when exposed to 405 nm light alone. In conclusion, C. difficile vegetative cells and spores can be successfully inactivated using 405 nm light, the sporicidal efficacy can be significantly enhanced when exposed in the presence of low concentration chlorinated disinfectants. Further research may lead to the potential use of 405 nm light decontamination in combination with selected hospital disinfectants to enhance C. difficile cleaning and infection control procedures.
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25
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Moorhead S, Maclean M, MacGregor SJ, Anderson JG. Comparative Sensitivity of Trichophyton and Aspergillus Conidia to Inactivation by Violet-Blue Light Exposure. Photomed Laser Surg 2015; 34:36-41. [PMID: 26595713 DOI: 10.1089/pho.2015.3922] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE To investigate the use of 405 nm light for inhibiting the growth of selected species of dermatophytic and saprophytic fungi. BACKGROUND DATA The increasing incidence and resilience of dermatophytic fungal infections is a major issue, and alternative treatment methods are being sought. METHODS The sensitivity of the dermatophytic fungi Trichophyton rubrum and Trichophyton mentagrophytes to 405 nm violet-blue light exposure was investigated, and the results compared with those obtained with the saprophytic fungus Aspergillus niger. Microconidia of T. rubrum and T. mentagrophytes and conidia of A. niger were seeded onto Sabauroud dextrose agar plates and irradiated with 405 nm light from an indium-gallium-nitride 99-DIE light-emitting diode (LED) array and the extent of inhibition was measured. RESULTS Germination of the microconidia of the Trichophyton species was completely inhibited using an irradiance of 35 mW/cm(2) for 4 h (dose of 504 J/cm(2)). A. niger conidia showed greater resistance, and colonial growth developed after light exposure. In liquid suspension tests, 405 nm light dose levels of 360, 720, and 1440 J/cm(2) resulted in complete inactivation of T. rubrum microconidia, whereas A. niger showed greater resistance, and at the highest dose level applied (1440 J/cm(2)) although A niger hyphae were completely inactivated, only a 3-log10 reduction of a 5-log10 conidial suspension was achieved. CONCLUSIONS The study results demonstrate the relatively high sensitivity of Trichophyton microconidia to 405 nm violet-blue light, and this is may be of potential interest regarding the control and treatment of dermatophyte infections.
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Affiliation(s)
- Sian Moorhead
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Michelle Maclean
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Scott J MacGregor
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - John G Anderson
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
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Risović D, Maver-Bišćanin M, Mravak-Stipetić M, Bukovski S, Bišćanin A. Quantitative investigation of efficiency of ultraviolet and visible light in eradication of Candida albicans in vitro. Photomed Laser Surg 2015; 32:232-9. [PMID: 24697585 DOI: 10.1089/pho.2013.3691] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
OBJECTIVE The aim of this study was to quantitatively investigate the efficiency of the ultraviolet (UV) and visible light in eradication of Candida albicans in vitro; in particular, to determine, for selected wavelengths, the specific eradication coefficients and thresholds in terms of energy density levels required to effect 3.0log10 and 4.0log10 reduction. BACKGROUND DATA Oral candidosis is the most common infection of the oral cavity and is caused by Candida species. The widespread use of topical and systemic antifungal agents as conventional treatment for oral candidosis has resulted in the development of resistance in C. albicans. Therefore, it has become necessary to develop alternative therapies for the treatment of oral candidosis. METHODS C. albicans ATCC(®) 90028(™) was irradiated with 254 nm, 365 nm, 406 nm, 420 nm, and broadband Xe spectrum. For each wavelength, a fit of experimental data (survival fraction vs. applied energy density) with an exponential decay function enabled estimation of the specific eradication coefficients and thresholds. RESULTS Based on estimated specific efficiencies (Δ) and eradication thresholds (ET) of the investigated wavelengths, the ranking in eradication efficiency of C. albicans (most to least effective) is: 254 nm (Δ=6.1 mJ/cm(-2), ET99.99=56 mJ/cm(-2)), broadband Xe spectrum (Δ=27.7 mJ/cm(-2), ET99.99=255 mJ/cm(-2)), 365 nm (Δ=4.3 J/cm(-2), ET99.99=39 J/cm(-2)), 420 nm (Δ=0.65 J/cm(-2), ET99.99=6 J/cm(-2)), and 406 nm (Δ=11.4 J/cm(-2), ET99.99=104 J/cm(-2)). CONCLUSIONS The results provide insight into the wavelength-dependent dynamics of eradication of C. albicans. For each investigated wavelength, the eradication coefficient and corresponding eradication threshold were estimated. The observed different eradication efficiencies are consequence of different spectrally dependent inactivation mechanisms. The established methodology enables unambiguous quantitative comparison of eradication efficiencies of optical radiation and selection of most effective wavelengths for clinical and therapeutic use.
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Affiliation(s)
- Dubravko Risović
- 1 Molecular Physics Laboratory, Ruđer Bošković Institute , Bijenicka, Zagreb, Croatia
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Liang JY, Cheng CW, Yu CH, Chen LY. Investigations of blue light-induced reactive oxygen species from flavin mononucleotide on inactivation of E. coli. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 143:82-8. [PMID: 25617617 DOI: 10.1016/j.jphotobiol.2015.01.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 12/24/2014] [Accepted: 01/05/2015] [Indexed: 01/11/2023]
Abstract
The micronutrients in many cellular processes, riboflavin, flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD) are photo-sensitive to UV and visible light for generating reactive oxygen species (ROS). Produced from phosphorylation of riboflavin, FMN is more water-soluble and rapidly transformed into free riboflavin after ingestion. This study investigated the application of visible blue light with FMN to development of an effective antimicrobial treatment. The photosensitization of bacterial viability with FMN was investigated by light quality, intensity, time, and irradiation dosage. The blue light-induced photochemical reaction with FMN could inactivate Escherichiacoli by the generated ROS in damaging nucleic acids, which was validated. This novel photodynamic technique could be a safe practice for photo-induced inactivation of environmental microorganism to achieve hygienic requirements in food processing.
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Affiliation(s)
- Ji-Yuan Liang
- Department of Biotechnology, Ming-Chuan University, Taoyüan 33343, Taiwan
| | - Chien-Wei Cheng
- Department of Biotechnology, Ming-Chuan University, Taoyüan 33343, Taiwan; Department of Restaurant and Institutional Management, Shih-Chien University, Taipei 10462, Taiwan
| | - Chin-Hao Yu
- Department of Biotechnology, Ming-Chuan University, Taoyüan 33343, Taiwan
| | - Liang-Yü Chen
- Department of Biotechnology, Ming-Chuan University, Taoyüan 33343, Taiwan.
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Maclean M, McKenzie K, Anderson J, Gettinby G, MacGregor S. 405 nm light technology for the inactivation of pathogens and its potential role for environmental disinfection and infection control. J Hosp Infect 2014; 88:1-11. [DOI: 10.1016/j.jhin.2014.06.004] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 06/17/2014] [Indexed: 01/22/2023]
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207-nm UV light - a promising tool for safe low-cost reduction of surgical site infections. I: in vitro studies. PLoS One 2013; 8:e76968. [PMID: 24146947 PMCID: PMC3797730 DOI: 10.1371/journal.pone.0076968] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 09/05/2013] [Indexed: 11/19/2022] Open
Abstract
Background 0.5% to 10% of clean surgeries result in surgical-site infections, and attempts to reduce this rate have had limited success. Germicidal UV lamps, with a broad wavelength spectrum from 200 to 400 nm are an effective bactericidal option against drug-resistant and drug-sensitive bacteria, but represent a health hazard to patient and staff. By contrast, because of its limited penetration, ∼200 nm far-UVC light is predicted to be effective in killing bacteria, but without the human health hazards to skin and eyes associated with conventional germicidal UV exposure. Aims The aim of this work was to test the biophysically-based hypothesis that ∼200 nm UV light is significantly cytotoxic to bacteria, but minimally cytotoxic or mutagenic to human cells either isolated or within tissues. Methods A Kr-Br excimer lamp was used, which produces 207-nm UV light, with a filter to remove higher-wavelength components. Comparisons were made with results from a conventional broad spectrum 254-nm UV germicidal lamp. First, cell inactivation vs. UV fluence data were generated for methicillin-resistant S. aureus (MRSA) bacteria and also for normal human fibroblasts. Second, yields of the main UV-associated pre-mutagenic DNA lesions (cyclobutane pyrimidine dimers and 6-4 photoproducts) were measured, for both UV radiations incident on 3-D human skin tissue. Results We found that 207-nm UV light kills MRSA efficiently but, unlike conventional germicidal UV lamps, produces little cell killing in human cells. In a 3-D human skin model, 207-nm UV light produced almost no pre-mutagenic UV-associated DNA lesions, in contrast to significant yields induced by a conventional germicidal UV lamp. Conclusions As predicted based on biophysical considerations, 207-nm light kills bacteria efficiently but does not appear to be significantly cytotoxic or mutagenic to human cells. Used appropriately, 207-nm light may have the potential for safely and inexpensively reducing surgical-site infection rates, including those of drug-resistant origin.
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