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Stewart CF, McGoldrick P, Anderson JG, MacGregor SJ, Atreya CD, Maclean M. Microbial reduction of prebagged human plasma using 405 nm light and its effects on coagulation factors. AMB Express 2024; 14:66. [PMID: 38842656 PMCID: PMC11156813 DOI: 10.1186/s13568-024-01725-0] [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: 02/12/2024] [Accepted: 05/27/2024] [Indexed: 06/07/2024] Open
Abstract
Bacterial contamination is the most prevalent infectious complication of blood transfusion in the developed world. To mitigate this, several ultraviolet light-based pathogen reduction technologies (PRTs), some of which require photo-chemicals, have been developed to minimize infection transmission. Relative to UV light, visible 405-nm light is safer and has shown potential to be developed as a PRT for the in situ treatment of ex vivo human plasma and platelet concentrates, without the need for photo-chemicals. This study investigates the effect of 405-nm light on human plasma, with focus on the compatibility of antimicrobial light doses with essential plasma clotting factors. To determine an effective antimicrobial dose that is compatible with plasma, prebagged human plasma (up to 300 mL) was seeded with common microbial contaminants and treated with increasing doses of 405-nm light (16 mW cm-2; ≤ 403 J cm-2). Post-exposure plasma protein integrity was investigated using an AOPP assay, in vitro coagulation tests, and ELISA-based measurement of fibrinogen and Protein S. Microbial contamination in 300 mL prebagged human plasma was significantly reduced (P ≤ 0.05) after exposure to ≤ 288 J cm-2, with microbial loads reduced by > 96.2%. This dose did not significantly affect the plasma protein quality parameters tested (P > 0.05). Increased doses (≥ 345 J cm-2) resulted in a 4.3% increase in clot times with no statistically significant change in protein activity or levels. Overall, this study has demonstrated that the effective microbicidal 405 light dose shows little to no negative effect on plasma quality.
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Affiliation(s)
- Caitlin F Stewart
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow, UK
| | - Preston McGoldrick
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK
| | - John G Anderson
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow, UK
| | - Scott J MacGregor
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow, UK
| | - Chintamani D Atreya
- Office of Blood Research and Review, Center for Biologics Evaluation and Research (CBER), Food and Drug Administration, Silver Spring, MD, USA
| | - Michelle Maclean
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow, UK.
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK.
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Kaldhone PR, Azodi N, Markle HL, Dahiya N, Stewart C, Anderson J, MacGregor S, Maclean M, Nakhasi HL, Gannavaram S, Atreya C. The Preclinical Validation of 405 nm Light Parasiticidal Efficacy on Leishmania donovani in Ex Vivo Platelets in a Rag2 -/- Mouse Model. Microorganisms 2024; 12:280. [PMID: 38399684 PMCID: PMC10893240 DOI: 10.3390/microorganisms12020280] [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: 12/27/2023] [Revised: 01/18/2024] [Accepted: 01/19/2024] [Indexed: 02/25/2024] Open
Abstract
Violet-blue light of 405 nm in the visible spectrum at a dose of 270 J/cm2 alone has been shown to be an effective microbicidal tool for inactivating several bacteria, HIV-1, and Trypanosoma cruzi in ex vivo plasma and platelets. Unlike chemical- and ultraviolet (UV)-based pathogen inactivation methods for plasma and platelet safety, 405 nm light is shown to be less toxic to host cells at light doses that are microbicidal. In this report, we evaluated the parasiticidal activity of a 405 nm light treatment on platelets spiked with the Leishmania donovani parasite. Following the light treatment, parasite viability was observed to be near zero in both low- and high-titer-spiked platelets relative to controls. Furthermore, to test the residual infectivity after inactivation in vivo, the light-treated low-titer L. donovani-spiked platelets were evaluated in an immunodeficient Rag2-/- mouse model and monitored for 9 weeks. The parasiticidal efficacy of 405 nm light was evident from the lack of a presence of parasites in the mice spleens. Parasiticidal activity was confirmed to be mediated through 405 nm light-induced reactive oxygen species (ROS), as quantitatively measured by a 2',7'-Dichlorodihydrofluorescein diacetate (H2DCFDA)-based assay. Overall, these results confirm the complete inactivation of L. donovani spiked in ex vivo platelets by 405 nm light treatment and exemplify the utility of the Rag2-/- mouse infection model for the preclinical validation of the parasiticidal efficacy of 405 nm light and this light-based technology as a potential PRT for ex vivo platelets.
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Affiliation(s)
- Pravin R. Kaldhone
- Division of Blood Components and Devices, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA; (P.R.K.); (N.D.)
| | - Nazli Azodi
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA; (N.A.); (H.L.M.); (H.L.N.)
| | - Hannah L. Markle
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA; (N.A.); (H.L.M.); (H.L.N.)
| | - Neetu Dahiya
- Division of Blood Components and Devices, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA; (P.R.K.); (N.D.)
| | - Caitlin Stewart
- Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow G1 1XW, UK; (C.S.); (J.A.); (S.M.); (M.M.)
| | - John Anderson
- Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow G1 1XW, UK; (C.S.); (J.A.); (S.M.); (M.M.)
| | - Scott MacGregor
- Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow G1 1XW, UK; (C.S.); (J.A.); (S.M.); (M.M.)
| | - Michelle Maclean
- Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow G1 1XW, UK; (C.S.); (J.A.); (S.M.); (M.M.)
- The Robertson Trust Laboratory for Electronic Sterilization Technologies, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow G1 1XW, UK
| | - Hira L. Nakhasi
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA; (N.A.); (H.L.M.); (H.L.N.)
| | - Sreenivas Gannavaram
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA; (N.A.); (H.L.M.); (H.L.N.)
| | - Chintamani Atreya
- Division of Blood Components and Devices, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA; (P.R.K.); (N.D.)
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3
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Gardner A, Soni A, Cookson A, Brightwell G. Light tolerance of extended spectrum β-lactamase producing Escherichia coli strains after repetitive exposure to far-UVC and blue LED light. J Appl Microbiol 2023; 134:lxad124. [PMID: 37463831 DOI: 10.1093/jambio/lxad124] [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: 04/21/2023] [Revised: 06/01/2023] [Accepted: 06/13/2023] [Indexed: 07/20/2023]
Abstract
AIMS The aim of this study was to investigate dual far-UVC (Ultraviolet-C) (222 nm) and blue LED (Light Emitting Diode) (405 nm) light on the inactivation of extended spectrum β-lactamase-producing Escherichia coli (ESBL-Ec) and to determine if repetitive exposure to long pulses of light resulted in changes to light tolerance, and antibiotic susceptibility. METHODS AND RESULTS Antimicrobial efficiency of dual and individual light wavelengths and development of light tolerance in E. coli was evaluated through a spread plate method after exposure to light at 25 cm. Dual light exposure for 30 min resulted in a 5-6 log10 CFU mL-1 reduction in two ESBL-Ec and two antibiotic-sensitive control E. coli strains. The overall inhibition achieved by dual light treatment was always greater than the combined reductions (log10 CFU) observed from exposure to individual light wavelengths (combined 222-405 nm), indicating a synergistic relationship between blue LED and far-UVC light when used together. Repetitive long pulses of dual and individual far-UVC light exposure resulted in light tolerance in two ESBL-Ec strains but not the antibiotic-sensitive E. coli strains. Subsequent passages of repetitive light-treated ESBL-Ec strains continued to exhibit light tolerance. Antibiotic susceptibility was determined through a standard disk diffusion method. No changes were observed in the antibiotic susceptibility profiles for any of the four strains after exposure to either dual or individual wavelengths. CONCLUSIONS Dual light exposure was effective in the disinfection of ESBL-Ec in solution; however, antibiotic-resistant E. coli were able to develop light tolerance after repetitive exposure to light.
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Affiliation(s)
- Amanda Gardner
- Food Systems Integrity Team, AgResearch Ltd., Hopkirk Research Institute, Cnr University Ave and Library Road, Massey University, Palmerston North 4442, New Zealand
| | - Aswathi Soni
- Food Systems Integrity Team, AgResearch Ltd., Hopkirk Research Institute, Cnr University Ave and Library Road, Massey University, Palmerston North 4442, New Zealand
| | - Adrian Cookson
- Food Systems Integrity Team, AgResearch Ltd., Hopkirk Research Institute, Cnr University Ave and Library Road, Massey University, Palmerston North 4442, New Zealand
- School of Veterinary Medicine, Massey University Manawatu (Turitea), Tennent Drive, Palmerston North 4474, New Zealand
| | - Gale Brightwell
- Food Systems Integrity Team, AgResearch Ltd., Hopkirk Research Institute, Cnr University Ave and Library Road, Massey University, Palmerston North 4442, New Zealand
- New Zealand Food Safety Science and Research Centre, Massey University Manawatu (Turitea), Tennent Drive, Palmerston North 4474, New Zealand
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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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Thery T, Beney L, Grangeteau C, Dupont S. Sporicidal efficiency of an ultra-high irradiance (UHI) near UV/visible light treatment: An example of application to infected mandarins. Food Control 2023. [DOI: 10.1016/j.foodcont.2022.109568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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6
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Zhu X, Yan H, Cui Z, Li H, Zhou W, Liu Z, Zhang H, Manoli T, Mo H, Hu L. Ultrasound-assisted blue light killing Vibrio parahaemolyticus to improve salmon preservation. ULTRASONICS SONOCHEMISTRY 2023; 95:106389. [PMID: 37003214 PMCID: PMC10457575 DOI: 10.1016/j.ultsonch.2023.106389] [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: 01/09/2023] [Revised: 02/27/2023] [Accepted: 03/26/2023] [Indexed: 06/19/2023]
Abstract
Vibrio parahaemolyticus is a typical marine bacterium, which often contaminates seafood and poses a health risk to consumers. Some non-thermal sterilization technologies, such as ultrasonic field (UF) and blue light (BL) irradiation, have been widely used in clinical practice due to their efficiency, safety, and avoidance of drug resistance, but their application in food preservation has not been extensively studied. This study aims to investigate the effect of BL on V. parahaemolyticus in culture media and in ready-to-eat fresh salmon, and to evaluate the killing effectiveness of the UF combined with BL treatment on V. parahaemolyticus. The results showed that BL irradiation at 216 J/cm2 was effective in causing cell death (close to 100%), cell shrinkage and reactive oxygen species (ROS) burst in V. parahaemolyticus. Application of imidazole (IMZ), an inhibitor of ROS generation, attenuated the cell death induced by BL, indicating that ROS were involved in the bactericidal effects of BL on V. parahaemolyticus. Furthermore, UF for 15 min enhanced the bactericidal effect of BL at 216 J/cm2 on V. parahaemolyticus, with the bactericidal rate of 98.81%. In addition, BL sterilization did not affect the color and quality of salmon, and the additive UF treatment for 15 min did not significant impact on the color of salmon. These results suggest that BL or UF combined with BL treatment has potential for salmon preservation, however, it is crucial to strictly control the intensity of BL and the duration of UF treatment to prevent reducing the freshness and brightness of salmon.
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Affiliation(s)
- Xiaolin Zhu
- School of Food Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Han Yan
- School of Food Science, Henan Institute of Science and Technology, Xinxiang, Henan 453003, China; College of Applied Technology, Hezhou University, Hezhou, Guangxi 542899, China
| | - Zhenkun Cui
- School of Food Science, Henan Institute of Science and Technology, Xinxiang, Henan 453003, China.
| | - Hongbo Li
- School of Food Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Wei Zhou
- School of Food Science, Henan Institute of Science and Technology, Xinxiang, Henan 453003, China
| | - Zhenbin Liu
- School of Food Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Hao Zhang
- School of Food Science, Henan Institute of Science and Technology, Xinxiang, Henan 453003, China
| | - Tatiana Manoli
- Department of Meat, Fish and Seafood Technology, Odessa National Academy of Food Technologies, Odessa 65039, Ukraine
| | - Haizhen Mo
- School of Food Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China.
| | - Liangbin Hu
- School of Food Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
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Effectiveness of purple led for inactivation of Bacillus subtilis and Escherichia coli bacteria in in vitro sterilizers. BIOMEDICAL PHOTONICS 2023. [DOI: 10.24931/2413-9432-2022-11-4-4-10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Bacteria are inactivated using a technique called photodynamic inactivation, which combines light with a photosensitizer with the right spectrum. The objective of this study is to ascertain the eciency of purple LEDs for photoinactivating Bacillus subtilis and Escherichia coli bacteria as well as the ideal purple LED exposure energy density. This study technique involves exposing bacteria to purple LED radiation. Two elements of variation are used during irradiation. The first variation is the illumination variation at distances of 3 cm, 6 cm, 9 cm, and 12 cm. The second variation involves changing the amount of radiation for 30, 60, 90, and 120 minutes. The Total Plate Count (TPC) method was used to count the number of colonies. Statistical tests were utilized in data analysis, namely the One Way Anova test (analysis of variance). The results of this study indicated that 395 nm purple LED irradiation caused a decrease in Log CFU/mL of Bacillus subtilis and Escherichia coli bacteria. Inactivation of Bacillus subtilis bacteria showed a higher mortality percentage than Escherichia coli bacteria. Changes in other irradiation distances also showed a higher percentage of death for Bacillus subtilis bacteria than Escherichia coli bacteria. The highest percentage of death was 98.5% for Bacillus subtilis bacteria and 94.3% for Escherichia coli bacteria at position C with an irradiation distance of 3 cm and an energy density of 524 J/cm2 with an LED exposure time of 120 minutes. This shows that the percentage of death of bacteria Bacillus subtilis and Escherichia coli increased with increasing doses of LED energy with the greatest percentage of death in Gram-positive bacteria Bacillus subtilis.
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Messina G, Bosco R, Amodeo D, Nante N, De Palma I, Petri C, Cevenini G. Safer school with near-UV technology: novel applications for environmental hygiene. JOURNAL OF ENVIRONMENTAL HEALTH SCIENCE & ENGINEERING 2023; 21:157-165. [PMID: 36718267 PMCID: PMC9877489 DOI: 10.1007/s40201-023-00850-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 01/16/2023] [Indexed: 05/07/2023]
Abstract
Systems capable of disinfecting air and surfaces could reduce the risk of infectious diseases transmission. Aim: to evaluate the effectiveness of near-UV LED ceiling lamps, with a wavelength of 405 nm, in improving environmental hygiene. Between November and December 2020, we conducted an experimental study having a pre-post design in a kindergarten room in Siena where 4 ceiling lamps with 405 nm LED technology were installed. Twice per day, sampling was performed before (T0) and after treatment with near-UV (T1). We used between 8 and 12 pairs of contact plates to sample at various random spots each day. Air samplings were also performed. The plates were incubated at 22 and 36 °C. Significance was set at 95% (p < 0.05). The mean level of Colony Forming Unit (CFU) at T(0) was 249 (95% CI 193.1 - 305.0) at 36 °C and 535.2 (374.3 - 696.1) at 22 °C. The reduction was significant at T(1): by 65% at 36 °C and, 72% at 22 °C. Also, for air contamination: 95.3% (98.4-92.3). A dose threshold of about 5 J/cm2 was identified to have an 80% CFU abatement and remains nearly constant. The advantage of being able to use this technology in the presence of people is very important in the context of controlling environmental contamination. Graphical abstract
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Affiliation(s)
- G. Messina
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
- Post Graduate School of Public Health, Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - R. Bosco
- Post Graduate School of Public Health, Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - D. Amodeo
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - N. Nante
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
- Post Graduate School of Public Health, Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - I. De Palma
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - C. Petri
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - G. Cevenini
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
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B. Soro A, Shokri S, Nicolau-Lapeña I, Ekhlas D, Burgess CM, Whyte P, Bolton DJ, Bourke P, Tiwari BK. Current challenges in the application of the UV-LED technology for food decontamination. Trends Food Sci Technol 2022. [DOI: 10.1016/j.tifs.2022.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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10
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Amodeo D, Lucarelli V, De Palma I, Puccio A, Nante N, Cevenini G, Messina G. Efficacy of violet-blue light to inactive microbial growth. Sci Rep 2022; 12:20179. [PMID: 36424450 PMCID: PMC9691702 DOI: 10.1038/s41598-022-24563-1] [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: 08/01/2022] [Accepted: 11/17/2022] [Indexed: 11/26/2022] Open
Abstract
The increase in health care-associated infections and antibiotic resistance has led to a growing interest in the search for innovative technologies to solve these problems. In recent years, the interest of the scientific community has focused on violet-blue light at 405 nm (VBL405). This study aimed to assess the VBL405 efficiency in reducing microbial growth on surfaces and air. This descriptive study run between July and October 2020. Petri dishes were contaminated with P. aeruginosa, E. coli, S. aureus, S. typhimurium, K. pneumoniae and were placed at 2 and 3 m from a LED light source having a wavelength peak at 405 nm and an irradiance respectively of 967 and 497 µW/cm2. Simultaneously, the air in the room was sampled for 5 days with two air samplers (SAS) before and after the exposition to the VBL405 source. The highest microbial reduction was reached 2 m directly under the light source: S. typhimurium (2.93 log10), K. pneumoniae (2.30 log10), S. aureus (3.98 log10), E. coli (3.83 log10), P. aeruginosa (3.86 log10). At a distance of 3 m from the light source, the greatest reduction was observed for S. aureus (3.49 log10), and P. aeruginosa (3.80 log10). An average percent microbial reduction of about 70% was found in the sampled air after 12 h of exposure to VBL405. VBL405 has proven to contrast microbial growth on the plates. Implementing this technology in the environment to provide continuous disinfection and to control microbial presence, even in the presence of people, may be an innovative solution.
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Affiliation(s)
- Davide Amodeo
- grid.9024.f0000 0004 1757 4641Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Valentina Lucarelli
- grid.9024.f0000 0004 1757 4641Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Isa De Palma
- grid.9024.f0000 0004 1757 4641Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Alessandro Puccio
- grid.9024.f0000 0004 1757 4641Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Nicola Nante
- grid.9024.f0000 0004 1757 4641Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Gabriele Cevenini
- grid.9024.f0000 0004 1757 4641Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Gabriele Messina
- grid.9024.f0000 0004 1757 4641Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
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Yu X, Zheng P, Zou Y, Ye Z, Wei T, Lin J, Guo L, Yuk HG, Zheng Q. A review on recent advances in LED-based non-thermal technique for food safety: current applications and future trends. Crit Rev Food Sci Nutr 2022; 63:7692-7707. [PMID: 35369810 DOI: 10.1080/10408398.2022.2049201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Light-emitting diodes (LEDs) is an eco-friendly light source with broad-spectrum antimicrobial activity. Recent studies have extensively been conducted to evaluate its efficacy in microbiological safety and the potential as a preservation method to extend the shelf-life of foods. This review aims to present the latest update of recent studies on the basics (physical, biochemical and mechanical basics) and antimicrobial activity of LEDs, as well as its application in the food industry. The highlight will be focused on the effects of LEDs on different types (bacteria, yeast/molds, viruses) and forms (planktonic cells, biofilms, endospores, fungal toxin) of microorganisms. The antimicrobial activity of LEDs on various food matrices was also evaluated, together with further analysis on the food-related factors that lead to the differences in LEDs efficiency. Besides, the applications of LEDs on the food-related conditions, packaged food, and equipment that could enhance LEDs efficiency were discussed to explore the future trends of LEDs technology in the food industry. Overall, the present review provides important insights for future research and the application of LEDs in the food industry.
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Affiliation(s)
- Xinpeng Yu
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Peng Zheng
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Yuan Zou
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Zhiwei Ye
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Tao Wei
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Junfang Lin
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Liqiong Guo
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Hyun-Gyun Yuk
- Department of Food Science and Technology, Korea National University of Transportation, Chungbuk, Republic of Korea
| | - Qianwang Zheng
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
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12
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de Oliveira Assunção FF, Nascimento É, Chaves L, da Silva AMH, Martinez R, de Jesus Guirro RR. Inhibition of bacterial growth through LED (light-emitting diode) 465 and 630 nm: in vitro. Lasers Med Sci 2022; 37:2439-2447. [PMID: 35075597 DOI: 10.1007/s10103-022-03505-3] [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: 10/18/2021] [Accepted: 01/06/2022] [Indexed: 11/29/2022]
Abstract
Photobiomodulation has been used to inactivate bacterial growth, in different laser or LED protocols. Thus, the aim of this study was to verify the inhibition of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, in ATCC strains and bacteria collected from patients with skin burns, after irradiation with LED; 300 μl of saline solution with bacterial suspension was irradiated at a concentration of 0.5-0.63, by the McFarland scale, after five serial dilutions, with evaluation of pre- and post-irradiation pH and temperature control. The cultures were placed in a bacteriological incubator at 37 °C for 24 h for later counting of colony-forming units (CFU). Data were analyzed by Shapiro-Wilk tests and single-factor ANOVA, with Tukey post hoc (p < 0.05). Both wavelengths and energy densities tested showed inhibition of bacterial growth. The comparison of the irradiated groups (ATCC) with the control group showed the following: S. aureus and P. aeruginosa 465 nm (40 J/cm2) and 630 nm (50 J/cm2) and E. coli 465 nm (40 J/cm2) and 630 nm (30 J/cm2). Among the ATCC S. aureus groups, there was a difference for 630 nm (30 J/cm2) and 465 nm (30, 40, 50 J/cm2). The bacteria from the burned patients were S. aureus (30 and 50 J/cm2) and P. aeruginosa (50 J/cm2). We conclude that different bacterial strains were reduced into colony-forming units after LED irradiation.
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Affiliation(s)
- Flávia Fernanda de Oliveira Assunção
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900 - Ribeirão Preto, SP, CEP, 14049-900, Brazil
| | - Érika Nascimento
- Department of Internal Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Lucas Chaves
- Graduate Program in Public Health, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Alessandro Márcio Hakme da Silva
- Center for Engineering Applied To Heath School of Engineering of São Carlos, Postdoctoral Researcher, University of São Paulo, São Carlos, SP, Brazil
| | - Roberto Martinez
- Department of Internal Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Rinaldo Roberto de Jesus Guirro
- Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900 - Ribeirão Preto, SP, CEP, 14049-900, Brazil.
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13
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Greer A. Violet-blue Light Induces "Natural" Photodynamic Plasma Disinfection with Endogenous Sensitizers. Photochem Photobiol 2022; 98:513-515. [PMID: 35020199 DOI: 10.1111/php.13591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 01/09/2022] [Indexed: 11/29/2022]
Abstract
Naturally, endogenous porphyrins can provide sensitized disinfection power, and to photobiologists' delight, violet-blue light has potential virtues. But progress is needed before violet-blue light treatment can used for microbe treatment of blood samples, and yet safeguard against plasma protein photooxidation. A report by Maclean et al. in this issue of Photochemistry & Photobiology on microbe reduction of blood samples showing negligible competing protein photooxidation may bring that goal a step closer.
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Affiliation(s)
- Alexander Greer
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, New York, 11210, United States.,Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York, 10016, United States
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14
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Stewart CF, Tomb RM, Ralston HJ, Armstrong J, Anderson JG, MacGregor SJ, Atreya CD, Maclean M. Violet-blue 405-nm Light-based Photoinactivation for Pathogen Reduction of Human Plasma Provides Broad Antibacterial Efficacy Without Visible Degradation of Plasma Proteins. Photochem Photobiol 2021; 98:504-512. [PMID: 34935147 DOI: 10.1111/php.13584] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/15/2021] [Indexed: 11/28/2022]
Abstract
In transfusion medicine, bacterial contamination can occur in ex vivo stored blood plasma, and there are continued efforts to improve blood safety and reduce the risk of transfusion-transmitted infections. Visible 405-nm violet-blue light has demonstrated potential for in situ pathogen reduction in ex vivo stored plasma and platelet concentrates. This study investigates the broad-spectrum antibacterial efficacy and compatibility potential of 405-nm light for treatment of blood plasma. Human plasma seeded with bacteria at a range of densities (101 -103 , 104 -106 , 107 -108 CFU mL-1 ) was exposed to 360 J cm-2 405-nm light (1 h at 0.1 W cm-2 ), with this fixed dose selected based on the initial analysis of inactivation kinetics. One-dimensional protein mobility analysis and measurement of advanced oxidation protein products (AOPP) was conducted to evaluate compatibility of the antimicrobial dose with plasma proteins and, identify upper levels at which protein degradation can be detected. Broad-spectrum antibacterial efficacy was observed with a fixed treatment of 360 J cm-2 , with 98.9-100% inactivation achieved across all seeding densities for all organisms, except E. coli, which achieved 95.1-100% inactivation. At this dose (360 J cm-2 ), no signs of protein degradation occurred. Overall, 405-nm light shows promise for broad-spectrum bacterial inactivation in blood plasma, while preserving plasma protein integrity.
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Affiliation(s)
- Caitlin F Stewart
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - Rachael M Tomb
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - Heather J Ralston
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK
| | - Jack Armstrong
- Department of Biomedical Engineering, University of Strathclyde, 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
| | - Chintamani D Atreya
- Office of Blood Research and Review, Center for Biologics Evaluation and Research (CBER), Food and Drug Administration, Silver Spring, MD
| | - 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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15
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Rathnasinghe R, Jangra S, Miorin L, Schotsaert M, Yahnke C, Garcίa-Sastre A. The virucidal effects of 405 nm visible light on SARS-CoV-2 and influenza A virus. Sci Rep 2021; 11:19470. [PMID: 34593848 PMCID: PMC8484654 DOI: 10.1038/s41598-021-97797-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/26/2021] [Indexed: 12/23/2022] Open
Abstract
The germicidal potential of specific wavelengths within the electromagnetic spectrum is an area of growing interest. While ultra-violet (UV) based technologies have shown satisfactory virucidal potential, the photo-toxicity in humans coupled with UV associated polymer degradation limit their use in occupied spaces. Alternatively, longer wavelengths with less irradiation energy such as visible light (405 nm) have largely been explored in the context of bactericidal and fungicidal applications. Such studies indicated that 405 nm mediated inactivation is caused by the absorbance of porphyrins within the organism creating reactive oxygen species which result in free radical damage to its DNA and disruption of cellular functions. The virucidal potential of visible-light based technologies has been largely unexplored and speculated to be ineffective given the lack of porphyrins in viruses. The current study demonstrated increased susceptibility of lipid-enveloped respiratory pathogens of importance such as SARS-CoV-2 (causative agent of COVID-19) and influenza A virus to 405 nm, visible light in the absence of exogenous photosensitizers thereby indicating a potential alternative porphyrin-independent mechanism of visible light mediated viral inactivation. These results were obtained using less than expected irradiance levels which are considered safe for humans and commercially achievable. Our results support further exploration of the use of visible light technology for the application of continuous decontamination in occupied areas within hospitals and/or infectious disease laboratories, specifically for the inactivation of respiratory pathogens such as SARS-CoV-2 and Influenza A.
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Affiliation(s)
- Raveen Rathnasinghe
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Sonia Jangra
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Lisa Miorin
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Michael Schotsaert
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | | | - Adolfo Garcίa-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
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16
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Patil VV, Lim J, Lee JY. Strategic Synchronization of 7,7-Dimethyl-5,7-dihydroindeno[2,1- b]carbazole for Narrow-Band, Pure Violet Organic Light-Emitting Diodes with an Efficiency of > 5% and a CIE y Coordinate of < 0.03. ACS APPLIED MATERIALS & INTERFACES 2021; 13:14440-14446. [PMID: 33749250 DOI: 10.1021/acsami.1c02635] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A novel violet emitter, 1,3-bis[10,10-dimethyl-10H-indeno[2,1-b]]indolo[3,2,1-jk]indolo[1',2',3':1,7]indolo[3,2-b]carbazole (m-FLDID), was designed and synthesized by meta-oriented bis-fusion of two 7,7-dimethyl-5,7-dihydroindeno[2,1-b]carbazole (DMID) subunits for use in a pure violet organic light-emitting diode (OLED). Incorporation of the DMID subunits effectively reduced the nonradiative recombination rate, improving the photoluminescence quantum yield of the m-FLDID emitter. The meta-oriented bis-fusion of the two DMID subunits not only triggered an alternative distribution of the frontier orbitals but also effectively locked the π-conjugation chain, which ultimately resulted in a narrow-band, pure violet emission of the m-FLDID emitter. Doped m-FLDID devices possessed an external quantum efficiency (EQE) of > 5%, pure violet emission with a maximum at 407 nm, a narrow full width at half-maximum of 17 nm, and a Commission Internationale de l'éclairage y coordinate of less than 0.03. This is the first work reporting an EQE of > 5% and an extremely narrow emission spectrum for a pure violet emitter.
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Affiliation(s)
- Vilas Venunath Patil
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 440-746, Korea
| | - Junseop Lim
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 440-746, Korea
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 440-746, Korea
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17
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The viability of human cells irradiated with 470-nm light at various radiant energies in vitro. Lasers Med Sci 2021; 36:1661-1670. [PMID: 33486613 DOI: 10.1007/s10103-021-03250-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 01/10/2021] [Indexed: 10/22/2022]
Abstract
Blue light is known to be antimicrobial, but its effect on normal cutaneous and subcutaneous cells remains unclear. Therefore, we studied the effect of 470-nm light on the viability of adult and neonatal human dermal fibroblasts, Jurkat T-cells, and THP-1 monocytes in vitro. Each culture was irradiated with 0, 3, 55, or 110 J/cm2 of 470-nm light and subjected to trypan blue assay to ascertain viability. Further, MTT, neutral red, and fluorescence assays of fibroblasts were performed, and cell morphology visualized using bright field and fluorescence microscopy. At each dose and in each of the four cell lines, there was no significant difference in cell concentration between irradiated and non-irradiated cultures, even though irradiation with 55 J/cm2 or 110 J/cm2 slightly decreased cell count. Light microscopy showed progressive morphological changes in the fibroblasts as energy fluence increased from 55 to 110 J/cm2. Irradiation at 3 J/cm2 produced a slight but non-significant increase in the viability of Jurkat T-cells and THP-1 monocytes. In contrast, at 110 J/cm2 radiant exposure, irradiation slightly decreased the viability of all four cells. While 3 J/cm2 appears stimulatory, our finding that 110 J/cm2 produces a slight decrease in viability and engenders morphological changes in fibroblasts, suggesting that such high doses should be avoided in blue light treatments.
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18
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Low-power lasers on bacteria: stimulation, inhibition, or effectless? Lasers Med Sci 2021; 36:1791-1805. [PMID: 33486614 DOI: 10.1007/s10103-021-03258-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/19/2021] [Indexed: 10/22/2022]
Abstract
Clinical protocols based on low-power lasers have been widely used for inflammation process resolution improvement, pain relief, wound healing, and nerve regeneration. However, there are concerns if exposure to such lasers could have negative effects on infected organs and tissues. There are experimental data suggesting exposure to radiations emitted by low-power lasers either induces stimulation, inhibition, or it is effectless on bacterial cultures. Thus, this review aimed to carry out a review of studies and to propose a hypothesis to explain why exposure to low-power lasers could stimulate, inhibit, or have no effect on bacteria. A literature search was carried out for assessment of published reports on effect of low-power lasers on bacteria. The experimental data suggest that keys for determining laser-induced effects on bacteria are specific physical laser and biological parameters. Final consequence on bacterial cells could depend on exposure to low-power laser which could either cause more stimulation of endogenous photoacceptors, more excitation of endogenous photosensitizers, or a balance between such effects.
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19
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Hadi J, Wu S, Brightwell G. Antimicrobial Blue Light versus Pathogenic Bacteria: Mechanism, Application in the Food Industry, Hurdle Technologies and Potential Resistance. Foods 2020; 9:E1895. [PMID: 33353056 PMCID: PMC7767196 DOI: 10.3390/foods9121895] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/12/2020] [Accepted: 12/16/2020] [Indexed: 12/12/2022] Open
Abstract
Blue light primarily exhibits antimicrobial activity through the activation of endogenous photosensitizers, which leads to the formation of reactive oxygen species that attack components of bacterial cells. Current data show that blue light is innocuous on the skin, but may inflict photo-damage to the eyes. Laboratory measurements indicate that antimicrobial blue light has minimal effects on the sensorial and nutritional properties of foods, although future research using human panels is required to ascertain these findings. Food properties also affect the efficacy of antimicrobial blue light, with attenuation or enhancement of the bactericidal activity observed in the presence of absorptive materials (for example, proteins on meats) or photosensitizers (for example, riboflavin in milk), respectively. Blue light can also be coupled with other treatments, such as polyphenols, essential oils and organic acids. While complete resistance to blue light has not been reported, isolated evidence suggests that bacterial tolerance to blue light may occur over time, especially through gene mutations, although at a slower rate than antibiotic resistance. Future studies can aim at characterizing the amount and type of intracellular photosensitizers across bacterial species and at assessing the oxygen-independent mechanism of blue light-for example, the inactivation of spoilage bacteria in vacuum-packed meats.
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Affiliation(s)
- Joshua Hadi
- AgResearch Ltd., Hopkirk Research Institute, Cnr University and Library Road, Massey University, Palmerston North 4442, New Zealand; (J.H.); (S.W.)
| | - Shuyan Wu
- AgResearch Ltd., Hopkirk Research Institute, Cnr University and Library Road, Massey University, Palmerston North 4442, New Zealand; (J.H.); (S.W.)
| | - Gale Brightwell
- AgResearch Ltd., Hopkirk Research Institute, Cnr University and Library Road, Massey University, Palmerston North 4442, New Zealand; (J.H.); (S.W.)
- New Zealand Food Safety Science and Research Centre, Tennent Drive, Massey University, Palmerston North 4474, New Zealand
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20
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Jankowska KI, Nagarkatti R, Acharyya N, Dahiya N, Stewart CF, Macpherson RW, Wilson MP, Anderson JG, MacGregor SJ, Maclean M, Dey N, Debrabant A, Atreya CD. Complete Inactivation of Blood Borne Pathogen Trypanosoma cruzi in Stored Human Platelet Concentrates and Plasma Treated With 405 nm Violet-Blue Light. Front Med (Lausanne) 2020; 7:617373. [PMID: 33330577 PMCID: PMC7732587 DOI: 10.3389/fmed.2020.617373] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 11/02/2020] [Indexed: 12/05/2022] Open
Abstract
The introduction of pathogen reduction technologies (PRTs) to inactivate bacteria, viruses and parasites in donated blood components stored for transfusion adds to the existing arsenal toward reducing the risk of transfusion-transmitted infectious diseases (TTIDs). We have previously demonstrated that 405 nm violet-blue light effectively reduces blood-borne bacteria in stored human plasma and platelet concentrates. In this report, we investigated the microbicidal effect of 405 nm light on one important bloodborne parasite Trypanosoma cruzi that causes Chagas disease in humans. Our results demonstrated that a light irradiance at 15 mWcm−2 for 5 h, equivalent to 270 Jcm−2, effectively inactivated T. cruzi by over 9.0 Log10, in plasma and platelets that were evaluated by a MK2 cell infectivity assay. Giemsa stained T. cruzi infected MK2 cells showed that the light-treated parasites in plasma and platelets were deficient in infecting MK2 cells and did not differentiate further into intracellular amastigotes unlike the untreated parasites. The light-treated and untreated parasite samples were then evaluated for any residual infectivity by injecting the treated parasites into Swiss Webster mice, which did not develop infection even after the animals were immunosuppressed, further demonstrating that the light treatment was completely effective for inactivation of the parasite; the light-treated platelets had similar in vitro metabolic and biochemical indices to that of untreated platelets. Overall, these results provide a proof of concept toward developing 405 nm light treatment as a pathogen reduction technology (PRT) to enhance the safety of stored human plasma and platelet concentrates from bloodborne T. cruzi, which causes Chagas disease.
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Affiliation(s)
- Katarzyna I Jankowska
- Laboratory of Cellular Hematology, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, United States
| | - Rana Nagarkatti
- Laboratory of Emerging Pathogens, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, United States
| | - Nirmallya Acharyya
- Laboratory of Emerging Pathogens, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, United States
| | - Neetu Dahiya
- Laboratory of Cellular Hematology, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, United States
| | - Caitlin F Stewart
- The Robertson Trust Laboratory for Electronic Sterilization Technologies, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Ruairidh W Macpherson
- The Robertson Trust Laboratory for Electronic Sterilization Technologies, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Mark P Wilson
- The Robertson Trust Laboratory for Electronic Sterilization Technologies, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - John G Anderson
- The Robertson Trust Laboratory for Electronic Sterilization Technologies, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Scott J MacGregor
- The Robertson Trust Laboratory for Electronic Sterilization Technologies, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Michelle Maclean
- The Robertson Trust Laboratory for Electronic Sterilization Technologies, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, United Kingdom.,Department of Biomedical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Neil Dey
- Canary, Inc., Acton, MA, United States
| | - Alain Debrabant
- Laboratory of Emerging Pathogens, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, United States
| | - Chintamani D Atreya
- Laboratory of Cellular Hematology, 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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21
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Hyun JE, Lee SY. Blue light-emitting diodes as eco-friendly non-thermal technology in food preservation. Trends Food Sci Technol 2020. [DOI: 10.1016/j.tifs.2020.09.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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22
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Hadi J, Dunowska M, Wu S, Brightwell G. Control Measures for SARS-CoV-2: A Review on Light-Based Inactivation of Single-Stranded RNA Viruses. Pathogens 2020; 9:E737. [PMID: 32911671 PMCID: PMC7558314 DOI: 10.3390/pathogens9090737] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/04/2020] [Accepted: 09/05/2020] [Indexed: 12/20/2022] Open
Abstract
SARS-CoV-2 is a single-stranded RNA virus classified in the family Coronaviridae. In this review, we summarize the literature on light-based (UV, blue, and red lights) sanitization methods for the inactivation of ssRNA viruses in different matrixes (air, liquid, and solid). The rate of inactivation of ssRNA viruses in liquid was higher than in air, whereas inactivation on solid surfaces varied with the type of surface. The efficacy of light-based inactivation was reduced by the presence of absorptive materials. Several technologies can be used to deliver light, including mercury lamp (conventional UV), excimer lamp (UV), pulsed-light, and light-emitting diode (LED). Pulsed-light technologies could inactivate viruses more quickly than conventional UV-C lamps. Large-scale use of germicidal LED is dependent on future improvements in their energy efficiency. Blue light possesses virucidal potential in the presence of exogenous photosensitizers, although femtosecond laser (ultrashort pulses) can be used to circumvent the need for photosensitizers. Red light can be combined with methylene blue for application in medical settings, especially for sanitization of blood products. Future modelling studies are required to establish clearer parameters for assessing susceptibility of viruses to light-based inactivation. There is considerable scope for improvement in the current germicidal light-based technologies and practices.
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Affiliation(s)
- Joshua Hadi
- AgResearch Ltd., Hopkirk Research Institute, Cnr University Ave and Library Road, Massey University, Palmerston North 4442, New Zealand; (J.H.); (S.W.)
| | - Magdalena Dunowska
- School of Veterinary Science, Massey University Manawatu (Turitea) Tennent Drive, Palmerston North 4474, New Zealand;
| | - Shuyan Wu
- AgResearch Ltd., Hopkirk Research Institute, Cnr University Ave and Library Road, Massey University, Palmerston North 4442, New Zealand; (J.H.); (S.W.)
| | - Gale Brightwell
- AgResearch Ltd., Hopkirk Research Institute, Cnr University Ave and Library Road, Massey University, Palmerston North 4442, New Zealand; (J.H.); (S.W.)
- New Zealand Food Safety Science and Research Centre, Massey University Manawatu (Turitea) Tennent Drive, Palmerston North 4474, New Zealand
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23
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Kwon C, Lee JM, Suh JY, Seo SJ, Lee Y, Kim YG. Effects of an electric toothbrush combined with 3-color light-emitting diodes on antiplaque and bleeding control: a randomized controlled study. J Periodontal Implant Sci 2020; 50:251-259. [PMID: 32643327 PMCID: PMC7443386 DOI: 10.5051/jpis.2001800090] [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: 03/10/2020] [Revised: 04/28/2020] [Accepted: 05/08/2020] [Indexed: 11/08/2022] Open
Abstract
Purpose This randomized controlled study aimed to evaluate the effects of an electric toothbrush with 3 colors of light-emitting diodes (LEDs) on antiplaque and bleeding control. Methods This randomized, placebo-controlled, double-blinded, parallel-group clinical trial included 50 healthy adults with gingivitis, who were randomly assigned to 2 groups. The experimental group used electric toothbrushes with 3 colors of LEDs and the control group used the same electric toothbrush as the experimental group, but with LED sources with one-hundredth of the strength. The subjects used the electric toothbrush 3 times a day for 4 minutes each time. As clinical indices, bleeding on marginal probing (BOMP), the Löe-Silness gingival index (GI), and the Turesky-Quigley-Hein plaque index (QHI) were assessed at baseline, at 3 weeks, and at 6 weeks. Results There were significant decreases in all clinical indices (BOMP, GI, QHI) in both the experimental and control groups compared to baseline at 3 weeks and at 6 weeks. In a comparison between the experimental and control groups, no statistically significant differences were observed for any clinical indices at 3 weeks (P>0.05). However, at 6 weeks, statistically significant differences were observed between the experimental and control groups in BOMP and GI, which are indicators of gingival inflammation (P<0.05). Conclusions This study demonstrated that an electric toothbrush combined with 3-color LEDs reduced gingival bleeding and inflammation after 6 weeks.
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Affiliation(s)
- Chakyoung Kwon
- Department of Periodontology, Kyungpook National University School of Dentistry, Daegu, Korea
| | - Jae Mok Lee
- Department of Periodontology, Kyungpook National University School of Dentistry, Daegu, Korea
| | - Jo Young Suh
- Department of Periodontology, Kyungpook National University School of Dentistry, Daegu, Korea
| | - Seung Jun Seo
- Department of Periodontology, Kyungpook National University School of Dentistry, Daegu, Korea
| | - Youngkyun Lee
- Department of Biochemistry, Kyungpook National University School of Dentistry, Daegu, Korea
| | - Yong Gun Kim
- Department of Periodontology, Kyungpook National University School of Dentistry, Daegu, Korea.
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24
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El Najjar N, van Teeseling MCF, Mayer B, Hermann S, Thanbichler M, Graumann PL. Bacterial cell growth is arrested by violet and blue, but not yellow light excitation during fluorescence microscopy. BMC Mol Cell Biol 2020; 21:35. [PMID: 32357828 PMCID: PMC7193368 DOI: 10.1186/s12860-020-00277-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/08/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Fluorescence microscopy is a powerful tool in cell biology, especially for the study of dynamic processes. Intensive irradiation of bacteria with UV, blue and violet light has been shown to be able to kill cells, but very little information is available on the effect of blue or violet light during live-cell imaging. RESULTS We show here that in the model bacterium Bacillus subtilis chromosome segregation and cell growth are rapidly halted by standard violet (405 nm) and blue light (CFP) (445-457 nm) excitation, whereas they are largely unaffected by green light (YFP). The stress sigma factor σB and the blue-light receptor YtvA are not involved in growth arrest. Using synchronized B. subtilis cells, we show that the use of blue light for fluorescence microscopy likely induces non-specific toxic effects, rather than a specific cell cycle arrest. Escherichia coli and Caulobacter crescentus cells also stop to grow after 15 one-second exposures to blue light (CFP), but continue growth when imaged under similar conditions in the YFP channel. In the case of E. coli, YFP excitation slows growth relative to white light excitation, whereas CFP excitation leads to cell death in a majority of cells. Thus, even mild violet/blue light excitation interferes with bacterial growth. Analyzing the dose-dependent effects of violet light in B. subtilis, we show that short exposures to low-intensity violet light allow for continued cell growth, while longer exposures do not. CONCLUSIONS Our experiments show that care must be taken in the design of live-cell imaging experiments in that violet or blue excitation effects must be closely controlled during and after imaging. Violet excitation during sptPALM or other imaging studies involving photoactivation has a threshold, below which little effects can be seen, but above which a sharp transition into cell death occurs. YFP imaging proves to be better suited for time-lapse studies, especially when cell cycle or cell growth parameters are to be examined.
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Affiliation(s)
- Nina El Najjar
- Center for Synthetic Microbiology (SYNMIKRO), Hans-Meerwein-Straße, 35043, Marburg, Germany.,Department of Chemistry, University of Marburg, Hans-Meerwein-Straße 4, 35032, Marburg, Germany
| | | | - Benjamin Mayer
- Center for Synthetic Microbiology (SYNMIKRO), Hans-Meerwein-Straße, 35043, Marburg, Germany.,Department of Chemistry, University of Marburg, Hans-Meerwein-Straße 4, 35032, Marburg, Germany
| | - Silke Hermann
- Center for Synthetic Microbiology (SYNMIKRO), Hans-Meerwein-Straße, 35043, Marburg, Germany.,Department of Chemistry, University of Marburg, Hans-Meerwein-Straße 4, 35032, Marburg, Germany
| | - Martin Thanbichler
- Center for Synthetic Microbiology (SYNMIKRO), Hans-Meerwein-Straße, 35043, Marburg, Germany.,Department of Biology, University of Marburg, Karl-von-Frisch-Straße 8, 35032, Marburg, Germany.,Max Planck Fellow Group "Bacterial Cell Biology", Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Straße 10, 35043, Marburg, Germany
| | - Peter L Graumann
- Center for Synthetic Microbiology (SYNMIKRO), Hans-Meerwein-Straße, 35043, Marburg, Germany. .,Department of Chemistry, University of Marburg, Hans-Meerwein-Straße 4, 35032, Marburg, Germany.
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25
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Blee JA, Roberts IS, Waigh TA. Membrane potentials, oxidative stress and the dispersal response of bacterial biofilms to 405 nm light. Phys Biol 2020; 17:036001. [PMID: 32050190 DOI: 10.1088/1478-3975/ab759a] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The majority of chronic infections are caused by biofilms, which have higher levels of antibiotic resistance than planktonic growth. Violet-blue 405 nm light has recently emerged as a novel bactericide, but limited studies have been conducted on its effectiveness against biofilms. We found that in response to 405 nm light both Pseudomonas aeruginosa and Bacillus subtilis biofilms exhibited cell dispersal and membrane potential hyperpolarisations. The response to 405 nm light depended on the stage of biofilm growth. The use of reactive oxygen species scavengers reduced membrane hyperpolarisation and biofilm dispersal in response to 405 nm light. This is the first time that membrane potential hyperpolarisations have been linked with photooxidative stress in bacteria and with biofilm dispersal. These results provide a new insight into the role of membrane potentials in the bacterial stress response and could be used in the development of 405 nm light based biofilm treatments.
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Affiliation(s)
- J A Blee
- Division of Infection, Lydia Becker Institute of Immunology and Inflammation Immunity & Respiratory Medicine, Immunity & Respiratory Medicine, School of Biological Sciences, University of Manchester, Oxford Road, M13 9PT, United Kingdom. Biological Physics, Department of Physics and Astronomy, School of Natural Sciences, University of Manchester, Oxford Road, M13 9PL, United Kingdom. Photon Science Institute, Alan Turing Building, University of Manchester, Oxford Road, M13 9PL, United Kingdom
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26
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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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27
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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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Violet-Blue Light Arrays at 405 Nanometers Exert Enhanced Antimicrobial Activity for Photodisinfection of Monomicrobial Nosocomial Biofilms. Appl Environ Microbiol 2019; 85:AEM.01346-19. [PMID: 31444205 PMCID: PMC6803304 DOI: 10.1128/aem.01346-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 08/16/2019] [Indexed: 12/13/2022] Open
Abstract
This study reports the efficacy of VBL and blue light (BL) and their antimicrobial activity against mature biofilms of a range of important nosocomial pathogens. While this study investigated the antibacterial activity of a range of wavelengths of between 375 and 450 nm and identified a specific wavelength region (∼405 nm) with increased antibacterial activity, decontamination was dependent on the bacterial species, strain, irradiation parameters, and experimental conditions. Further research with controlled experiments that ameliorate the heating effects and improve the optical properties are required to optimize the dosing parameters to advance the successful clinical translation of this technology. Light-emitting diodes (LEDs) demonstrate therapeutic effects for a range of biomedical applications, including photodisinfection. Bands of specific wavelengths (centered at 405 nm) are reported to be the most antimicrobial; however, there remains no consensus on the most effective irradiation parameters for optimal photodisinfection. The aim of this study was to assess decontamination efficiency by direct photodisinfection of monomicrobial biofilms using a violet-blue light (VBL) single-wavelength array (SWA) and multiwavelength array (MWA). Mature biofilms of nosocomial bacteria (Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus) were grown on 96-well polypropylene PCR plates. The biofilms were then exposed to VBL for 2,700 s (SWA) and 1,170 s (MWA) to deliver 0 to 670 J/cm2, and the antibacterial activity of VBL was assessed by comparing the seeding of the irradiated and the nonirradiated biofilms. Nonirradiated groups were used as controls. The VBL arrays were characterized optically (spectral irradiance and beam profile) and thermally. The SWA delivered 401-nm VBL and the MWA delivered between 379-nm and 452-nm VBL, albeit at different irradiances and with different beam profiles. In both arrays, the irradiated groups were exposed to increased temperatures compared to the nonirradiated controls. All bacterial isolates were susceptible to VBL and demonstrated reductions in the seeding of exposed biofilms compared with the nonirradiated controls. VBL at 405 nm exerted the most antimicrobial activity, exhibiting reductions in seeding of up to 94%. Decontamination efficiency is dependent on the irradiation parameters, bacterial species and strain, and experimental conditions. Controlled experiments that ameliorate the heating effects and improve the optical properties are required to optimize the dosing parameters to advance the successful clinical translation of this technology. IMPORTANCE This study reports the efficacy of VBL and blue light (BL) and their antimicrobial activity against mature biofilms of a range of important nosocomial pathogens. While this study investigated the antibacterial activity of a range of wavelengths of between 375 and 450 nm and identified a specific wavelength region (∼405 nm) with increased antibacterial activity, decontamination was dependent on the bacterial species, strain, irradiation parameters, and experimental conditions. Further research with controlled experiments that ameliorate the heating effects and improve the optical properties are required to optimize the dosing parameters to advance the successful clinical translation of this technology.
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29
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Cetinkaya Y, Yurt MNZ, Avni Oktem H, Yilmaz MD. A Monostyryl Boradiazaindacene (BODIPY)-based lanthanide-free colorimetric and fluorogenic probe for sequential sensing of copper (II) ions and dipicolinic acid as a biomarker of bacterial endospores. JOURNAL OF HAZARDOUS MATERIALS 2019; 377:299-304. [PMID: 31173979 DOI: 10.1016/j.jhazmat.2019.05.108] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/18/2019] [Accepted: 05/30/2019] [Indexed: 06/09/2023]
Abstract
A new catechol-substituted monostyryl boradiazaindacene (BODIPY)-based lanthanide-free colorimetric and fluorogenic probe was developed for the sequential detection of Cu2+ ions and dipicolinic acid (DPA), a distinctive biomarker of bacterial endospores, with high sensitivity and selectivity. In the presence of Cu2+ ions, the blue solution of the probe changes to cyan and the fluorescence is quenched, however, the cyan color changes to blue immediately and the fluorescence is restored on contact with DPA, resulting from competitive binding of DPA that interact with Cu2+ ions. A practical application by using Geobacillus stearothermophilus spores was further studied and as low as 1.0 x 105 spores were detected.
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Affiliation(s)
- Yagmur Cetinkaya
- Department of Bioengineering, Faculty of Engineering and Architecture, Konya Food and Agriculture University, 42080 Konya, Turkey
| | - Mediha Nur Zafer Yurt
- Research and Development Center for Diagnostic Kits (KIT-ARGEM), Konya Food and Agriculture University, 42080 Konya, Turkey; Institute of Science, Biotechnology Graduate Program, Konya Food and Agriculture University, Konya, 42080, Turkey
| | - Huseyin Avni Oktem
- Department of Biological Sciences, Middle East Technical University, 06800 Ankara, Turkey; Nanobiz R&D Ltd., Gallium Bld. No.18, METU Science Park, Ankara, Turkey
| | - M Deniz Yilmaz
- Department of Bioengineering, Faculty of Engineering and Architecture, Konya Food and Agriculture University, 42080 Konya, Turkey; Research and Development Center for Diagnostic Kits (KIT-ARGEM), Konya Food and Agriculture University, 42080 Konya, Turkey; Institute of Science, Biotechnology Graduate Program, Konya Food and Agriculture University, Konya, 42080, Turkey.
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30
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Weber DJ, Rutala WA, Sickbert-Bennett EE, Kanamori H, Anderson D. Continuous room decontamination technologies. Am J Infect Control 2019; 47S:A72-A78. [PMID: 31146855 DOI: 10.1016/j.ajic.2019.03.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The contaminated surface environment in the rooms of hospitalized patients is an important risk factor for the colonization and infection of patients with multidrug-resistant pathogens. Improved terminal cleaning and disinfection have been demonstrated to reduce the incidence of health care-associated infections. In the United States, hospitals generally perform daily cleaning and disinfection of patient rooms. However, cleaning and disinfection are limited by the presence of the patient in room (eg, current ultraviolet devices and hydrogen peroxide systems cannot be used) and the fact that after disinfection pathogenic bacteria rapidly recolonize surfaces and medical devices/equipment. For this reason, there has been great interest in developing methods of continuous room disinfection and/or "self-disinfecting" surfaces. This study will review the research on self-disinfecting surfaces (eg, copper-coated surfaces and persistent chemical disinfectants) and potential new room disinfection methods (eg, "blue light" and diluted hydrogen peroxide systems).
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31
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Stratford JP, Edwards CLA, Ghanshyam MJ, Malyshev D, Delise MA, Hayashi Y, Asally M. Electrically induced bacterial membrane-potential dynamics correspond to cellular proliferation capacity. Proc Natl Acad Sci U S A 2019; 116:9552-9557. [PMID: 31000597 PMCID: PMC6511025 DOI: 10.1073/pnas.1901788116] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Membrane-potential dynamics mediate bacterial electrical signaling at both intra- and intercellular levels. Membrane potential is also central to cellular proliferation. It is unclear whether the cellular response to external electrical stimuli is influenced by the cellular proliferative capacity. A new strategy enabling electrical stimulation of bacteria with simultaneous monitoring of single-cell membrane-potential dynamics would allow bridging this knowledge gap and further extend electrophysiological studies into the field of microbiology. Here we report that an identical electrical stimulus can cause opposite polarization dynamics depending on cellular proliferation capacity. This was demonstrated using two model organisms, namely Bacillus subtilis and Escherichia coli, and by developing an apparatus enabling exogenous electrical stimulation and single-cell time-lapse microscopy. Using this bespoke apparatus, we show that a 2.5-second electrical stimulation causes hyperpolarization in unperturbed cells. Measurements of intracellular K+ and the deletion of the K+ channel suggested that the hyperpolarization response is caused by the K+ efflux through the channel. When cells are preexposed to 400 ± 8 nm wavelength light, the same electrical stimulation depolarizes cells instead of causing hyperpolarization. A mathematical model extended from the FitzHugh-Nagumo neuron model suggested that the opposite response dynamics are due to the shift in resting membrane potential. As predicted by the model, electrical stimulation only induced depolarization when cells are treated with antibiotics, protonophore, or alcohol. Therefore, electrically induced membrane-potential dynamics offer a reliable approach for rapid detection of proliferative bacteria and determination of their sensitivity to antimicrobial agents at the single-cell level.
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Affiliation(s)
- James P Stratford
- School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom
- Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry, West Midlands, CV4 7AL,United Kingdom
| | - Conor L A Edwards
- School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom
| | - Manjari J Ghanshyam
- School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom
| | - Dmitry Malyshev
- School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom
| | - Marco A Delise
- School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom
| | - Yoshikatsu Hayashi
- Department of Biomedical Engineering, School of Biological Sciences, University of Reading, Reading, Berkshire, RG6 6AH, United Kingdom
| | - Munehiro Asally
- School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom;
- Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry, West Midlands, CV4 7AL,United Kingdom
- Bio-Electrical Engineering Innovation Hub, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom
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32
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Dos Anjos C, Sellera FP, Gargano RG, Lincopan N, Pogliani FC, Ribeiro MG, Jagielski T, Sabino CP. Algicidal effect of blue light on pathogenic Prototheca species. Photodiagnosis Photodyn Ther 2019; 26:210-213. [PMID: 30965146 DOI: 10.1016/j.pdpdt.2019.04.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/25/2019] [Accepted: 04/05/2019] [Indexed: 11/24/2022]
Abstract
Prototheca spp. are pathogenic algae with important zoonotic potential. Most importantly, these algae often infect dairy cattle. Since there is no effective therapy against the algae, the standard recommendation is the disposal or culling of infected cows to avoid outbreaks. This study investigated the ability of blue light to inactivate pathogenic Prototheca species. Blue LED light (λ = 410 nm) was used to inactivate in vitro suspensions of P. zopfii genotypes 1 and 2, and P. blaschkeae. Our results showed that blue light irradiation induced a strain-specific dose-dependent algicidal effect against all tested strains. P. zopfii genotype 1, was more sensitive than genotype 2 and P. blaschkeae was the most tolerant. Even though we observed different inactivation kinetics, all strains presented significant photoinactivation levels within feasible procedure periods. Therefore, we conclude that blue light irradiation offers promising potential for the development of novel technologies that control contaminations and infections caused by Prototheca spp.
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Affiliation(s)
- Carolina Dos Anjos
- Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Fábio Parra Sellera
- Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Ronaldo Gomes Gargano
- Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Nilton Lincopan
- Department of Microbiology, Institute for Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil; Department of Clinical and Toxicological Analysis, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Fabio Celidonio Pogliani
- Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Marcio Garcia Ribeiro
- Department of Veterinary Hygiene and Public Health, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Tomasz Jagielski
- Department of Applied Microbiology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Poland
| | - Caetano Padial Sabino
- Department of Clinical and Toxicological Analysis, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil; BioLambda, Scientific and Commercial LTD, Sao Paulo, SP, Brazil.
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Madronich S, Björn LO, McKenzie RL. Solar UV radiation and microbial life in the atmosphere. Photochem Photobiol Sci 2018; 17:1918-1931. [PMID: 29978175 DOI: 10.1039/c7pp00407a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Many microorganisms are alive while suspended in the atmosphere, and some seem to be metabolically active during their time there. One of the most important factors threatening their life and activity is solar ultraviolet (UV) radiation. Quantitative understanding of the spatial and temporal survival patterns in the atmosphere, and of the ultimate deposition of microbes to the surface, is limited by a number factors some of which are discussed here. These include consideration of appropriate spectral sensitivity functions for biological damage (e.g. inactivation), and the estimation of UV radiation impingent on a microorganism suspended in the atmosphere. We show that for several bacteria (E. coli, S. typhimurium, and P. acnes) the inactivation rates correlate well with irradiances weighted by the DNA damage spectrum in the UV-B spectral range, but when these organisms show significant UV-A (or visible) sensitivities, the correlations become clearly non-linear. The existence of these correlations enables the use of a single spectrum (here DNA damage) as a proxy for sensitivity spectra of other biological effects, but with some caution when the correlations are strongly non-linear. The radiative quantity relevant to the UV exposure of a suspended particle is the fluence rate at an altitude above ground, while down-welling irradiance at ground-level is the quantity most commonly measured or estimated in satellite-derived climatologies. Using a radiative transfer model that computes both quantities, we developed a simple parameterization to exploit the much larger irradiance data bases to estimate fluence rates, and present the first fluence-rate based climatology of DNA-damaging UV radiation in the atmosphere. The estimation of fluence rates in the presence of clouds remains a particularly challenging problem. Here we note that both reductions and enhancements in the UV radiation field are possible, depending mainly on cloud optical geometry and prevailing solar zenith angles. These complex effects need to be included in model simulations of the atmospheric life cycle of the organisms.
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Role of DNA Repair and Protective Components in Bacillus subtilis Spore Resistance to Inactivation by 400-nm-Wavelength Blue Light. Appl Environ Microbiol 2018; 84:AEM.01604-18. [PMID: 30054368 DOI: 10.1128/aem.01604-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 07/24/2018] [Indexed: 11/20/2022] Open
Abstract
The high intrinsic decontamination resistance of Firmicutes spores is important medically (disease) and commercially (food spoilage). Effective methods of spore eradication would be of considerable interest in the health care and medical product industries, particularly if the decontamination method effectively killed spores while remaining benign to both humans and sensitive equipment. Intense blue light at a ∼400 nm wavelength is one such treatment that has drawn significant interest. This work has determined the resistance of spores to blue light in an extensive panel of Bacillus subtilis strains, including wild-type strains and mutants that (i) lack protective components such as the spore coat and its pigment(s) or the DNA protective α/β-type small, acid-soluble spore proteins (SASP); (ii) have an elevated spore core water content; or (iii) lack enzymes involved in DNA repair, including those for homologous recombination and nonhomologous end joining (HR and NHEJ), apurinic/apyrimidinic endonucleases, nucleotide and base excision repair (NER and BER), translesion synthesis (TLS) by Y-family DNA polymerases, and spore photoproduct (SP) removal by SP lyase (SPL). The most important factors in spore blue light resistance were determined to be spore coats/pigmentation, α/β-type SASP, NER, BER, TLS, and SP repair. A major conclusion from this work is that blue light kills spores by DNA damage, and the results in this work indicate at least some of the specific DNA damage. It appears that high-intensity blue light could be a significant addition to the agents used to kill bacterial spores in applied settings.IMPORTANCE Effective methods of spore inactivation would be of considerable interest in the health care and medical products industries, particularly if the decontamination method effectively killed spores while remaining benign to both humans and sensitive equipment. Intense blue light radiation is one such treatment that has drawn significant interest. In this work, all known spore-protective features, as well as universal and spore-specific DNA repair mechanisms, were tested in a systematic fashion for their contribution to the resistance of spores to blue light radiation.
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Plavskii VY, Mikulich AV, Tretyakova AI, Leusenka IA, Plavskaya LG, Kazyuchits OA, Dobysh II, Krasnenkova TP. Porphyrins and flavins as endogenous acceptors of optical radiation of blue spectral region determining photoinactivation of microbial cells. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2018; 183:172-183. [PMID: 29715591 DOI: 10.1016/j.jphotobiol.2018.04.021] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/19/2018] [Accepted: 04/14/2018] [Indexed: 12/23/2022]
Abstract
It is shown that exposure of suspensions of gram-positive Staphylococcus aureus, gram-negative Escherichia coli and yeast-like fungi Candida albicans to laser radiation of blue spectral region with 405 and 445 nm causes their growth inhibition without prior addition of exogenous photosensitizers. It is experimentally confirmed that compounds of flavin type capable of sensitizing the formation of reactive oxygen species can act as acceptors of optical radiation of blue spectral region determining its antimicrobial effect along with endogenous metal-free porphyrins (the role of endogenous porphyrins has been confirmed earlier by a number of researchers). The participation of these compounds in the antimicrobial effect of laser radiation is supported by the registration of porphyrin and flavin fluorescence in extracts of microbial cells upon excitation by radiation used to inactivate the pathogens. In addition, the intensity of the porphyrin fluorescence in extracts of microbial cells in the transition from radiation with λ = 405 nm to radiation with λ = 445 nm decreases by 15-30 times, whereas the photosensitivity of the cells under study in this transition decreases only 3.7-6.2 times. The contribution of porphyrin photosensitizers is most pronounced upon exposure to radiation with λ = 405 nm (absorption maximum of the Soret band of porphyrins), and flavins - upon exposure to radiation with λ = 445 nm (maximum in the flavin absorption spectrum and minimum in the absorption spectrum of porphyrins). The ratio between the intensity of the porphyrin and flavin components in the fluorescence spectrum of extracts depends on the type of microbial cells.
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Affiliation(s)
- V Yu Plavskii
- State Scientific Institution B.I. Stepanov Institute of Physics of the National Academy of Sciences of Belarus, 220072 Minsk, 68-2 Nezavisimosti ave., Belarus.
| | - A V Mikulich
- State Scientific Institution B.I. Stepanov Institute of Physics of the National Academy of Sciences of Belarus, 220072 Minsk, 68-2 Nezavisimosti ave., Belarus
| | - A I Tretyakova
- State Scientific Institution B.I. Stepanov Institute of Physics of the National Academy of Sciences of Belarus, 220072 Minsk, 68-2 Nezavisimosti ave., Belarus
| | - I A Leusenka
- State Scientific Institution B.I. Stepanov Institute of Physics of the National Academy of Sciences of Belarus, 220072 Minsk, 68-2 Nezavisimosti ave., Belarus
| | - L G Plavskaya
- State Scientific Institution B.I. Stepanov Institute of Physics of the National Academy of Sciences of Belarus, 220072 Minsk, 68-2 Nezavisimosti ave., Belarus
| | - O A Kazyuchits
- Republican Manufacturing Unitary Enterprise Academpharm, 220141 Minsk, Kuprevich st. 5/3, Belarus
| | - I I Dobysh
- Republican Manufacturing Unitary Enterprise Academpharm, 220141 Minsk, Kuprevich st. 5/3, Belarus
| | - T P Krasnenkova
- Republican Manufacturing Unitary Enterprise Academpharm, 220141 Minsk, Kuprevich st. 5/3, Belarus
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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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Gold nanoparticle-based colorimetric sensing of dipicolinic acid from complex samples. Anal Bioanal Chem 2018; 410:1805-1815. [DOI: 10.1007/s00216-017-0836-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 11/24/2017] [Accepted: 12/15/2017] [Indexed: 12/29/2022]
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Alpha-ketoglutarate protects Streptomyces coelicolor from visible light-induced phototoxicity. Biochem Biophys Rep 2017; 9:22-28. [PMID: 29114580 PMCID: PMC5632709 DOI: 10.1016/j.bbrep.2016.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 10/28/2016] [Accepted: 11/03/2016] [Indexed: 01/12/2023] Open
Abstract
It has been known that some Streptomyces species, including the model strain Streptomyces coelicolor, are vulnerable to visible light. Much evidence demonstrated that the phototoxicity induced by visible light is a consequence of the formation of intracellular reactive oxygen species (ROS), which are potentially harmful to cells. In this study, we found that α-ketoglutarate (α-KG) has a protective role against the phototoxicity in S. coelicolor. It could be because that α-KG can detoxify the ROS with the concomitant formation of succinate, which mediates the cells getting into anaerobiosis to produce more NADH and maintain intracellular redox homeostasis, a situation that was demonstrated by overexpressing gdhA in S. coelicolor. This finding, therefore, connects the central metabolites with the bacterial resistance against phototoxicity effect induced by visible light. Streptomyces coelicolor is sensitive to visible light induced phototoxicity. α-ketoglutarate (α-KG) has a protective role against phototoxicity in S. coelicolor. α-KG maintains intracellular NAD/NADH redox homeostasis to resist phototoxicity.
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Wang Y, Wang Y, Wang Y, Murray CK, Hamblin MR, Hooper DC, Dai T. Antimicrobial blue light inactivation of pathogenic microbes: State of the art. Drug Resist Updat 2017; 33-35:1-22. [PMID: 29145971 DOI: 10.1016/j.drup.2017.10.002] [Citation(s) in RCA: 167] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 06/28/2017] [Accepted: 10/02/2017] [Indexed: 12/20/2022]
Abstract
As an innovative non-antibiotic approach, antimicrobial blue light in the spectrum of 400-470nm has demonstrated its intrinsic antimicrobial properties resulting from the presence of endogenous photosensitizing chromophores in pathogenic microbes and, subsequently, its promise as a counteracter of antibiotic resistance. Since we published our last review of antimicrobial blue light in 2012, there have been a substantial number of new studies reported in this area. Here we provide an updated overview of the findings from the new studies over the past 5 years, including the efficacy of antimicrobial blue light inactivation of different microbes, its mechanism of action, synergism of antimicrobial blue light with other angents, its effect on host cells and tissues, the potential development of resistance to antimicrobial blue light by microbes, and a novel interstitial delivery approach of antimicrobial blue light. The potential new applications of antimicrobial blue light are also discussed.
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Affiliation(s)
- Yucheng Wang
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Cancer Center, Aviation General Hospital, Beijing, China; Department of Medical Oncology, Beijing Institute of Translational Medicine, Chinese Academy of Sciences, Beijing, China
| | - Ying Wang
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Department of Laser Medicine, Chinese PLA General Hospital, Beijing, China
| | - Yuguang Wang
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Center of Digital Dentistry, School and Hospital of Stomatology, Peking University, Beijing, China
| | - Clinton K Murray
- Infectious Disease Service, San Antonio Military Medical Center, JBSA-Fort Sam Houston, TX, USA
| | - Michael R Hamblin
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - David C Hooper
- Division of Infectious Diseases, 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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Tomb RM, Maclean M, Coia JE, MacGregor SJ, Anderson JG. Assessment of the potential for resistance to antimicrobial violet-blue light in Staphylococcus aureus. Antimicrob Resist Infect Control 2017; 6:100. [PMID: 29046782 PMCID: PMC5639585 DOI: 10.1186/s13756-017-0261-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 09/18/2017] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Antimicrobial violet-blue light in the region of 405 nm is emerging as an alternative technology for hospital decontamination and clinical treatment. The mechanism of action is the excitation of endogenous porphyrins within exposed microorganisms, resulting in ROS generation, oxidative damage and cell death. Although resistance to 405 nm light is not thought likely, little evidence has been published to support this. This study was designed to establish if there is potential for tolerance development, using the nosocomial pathogen Staphylococcus aureus as the model organism. METHODS The first stage of this study investigated the potential for S. aureus to develop tolerance to high-intensity 405 nm light if pre-cultured in low-level stress violet-blue light (≤1 mW/cm2) conditions. Secondly, the potential for tolerance development in bacteria subjected to repeated sub-lethal exposure was compared by carrying out 15 cycles of exposure to high-intensity 405 nm light, using a sub-lethal dose of 108 J/cm2. Inactivation kinetics and antibiotic susceptibility were also compared. RESULTS When cultured in low-level violet-blue light conditions, S. aureus required a greater dose of high-intensity 405 nm light for complete inactivation, however this did not increase with multiple (3) low-stress cultivations. Repeated sub-lethal exposures indicated no evidence of bacterial tolerance to 405 nm light. After 15 sub-lethal exposures 1.2 and 1.4 log10 reductions were achieved for MSSA and MRSA respectively, which were not significantly different to the initial 1.3 log10 reductions achieved (P = 0.242 & 0.116, respectively). Antibiotic susceptibility was unaffected, with the maximum change in zone of inhibition being ± 2 mm. CONCLUSIONS Repeated sub-lethal exposure of non-proliferating S. aureus populations did not affect the susceptibility of the organism to 405 nm light, nor to antibiotics. Culture in low-level violet-blue light prior to 405 nm light exposure may increase oxidative stress responses in S. aureus, however, inactivation still occurs and results demonstrate that this is unlikely to be a selective process. These results demonstrate that tolerance from repeated exposure is unlikely to occur, and further supports the potential development of 405 nm light for clinical decontamination and treatment applications.
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Affiliation(s)
- Rachael M Tomb
- 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
| | - John E Coia
- Department of Clinical Microbiology, Glasgow Royal Infirmary, Glasgow, UK
| | - Scott J MacGregor
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - John G Anderson
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
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Tomb RM, Maclean M, Coia JE, Graham E, McDonald M, Atreya CD, MacGregor SJ, Anderson JG. New Proof-of-Concept in Viral Inactivation: Virucidal Efficacy of 405 nm Light Against Feline Calicivirus as a Model for Norovirus Decontamination. FOOD AND ENVIRONMENTAL VIROLOGY 2017; 9:159-167. [PMID: 28040848 PMCID: PMC5429381 DOI: 10.1007/s12560-016-9275-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 12/10/2016] [Indexed: 06/01/2023]
Abstract
The requirement for novel decontamination technologies for use in hospitals is ever present. One such system uses 405 nm visible light to inactivate microorganisms via ROS-generated oxidative damage. Although effective for bacterial and fungal inactivation, little is known about the virucidal effects of 405 nm light. Norovirus (NoV) gastroenteritis outbreaks often occur in the clinical setting, and this study was designed to investigate potential inactivation effects of 405 nm light on the NoV surrogate, feline calicivirus (FCV). FCV was exposed to 405 nm light whilst suspended in minimal and organically-rich media to establish the virucidal efficacy and the effect biologically-relevant material may play in viral susceptibility. Antiviral activity was successfully demonstrated with a 4 Log10 (99.99%) reduction in infectivity when suspended in minimal media evident after a dose of 2.8 kJ cm-2. FCV exposed in artificial faeces, artificial saliva, blood plasma and other organically rich media exhibited an equivalent level of inactivation using between 50-85% less dose of the light, indicating enhanced inactivation when the virus is present in organically-rich biologically-relevant media. Further research in this area could aid in the development of 405 nm light technology for effective NoV decontamination within the hospital environment.
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Affiliation(s)
- Rachael M Tomb
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow, G1 1XW, Scotland, UK.
| | - Michelle Maclean
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow, G1 1XW, Scotland, UK
- Department of Biomedical Engineering, University of Strathclyde, Wolfson Centre, 106 Rottenrow, Glasgow, Scotland, UK
| | - John E Coia
- Department of Clinical Microbiology, Glasgow Royal Infirmary, Glasgow, Scotland, UK
| | - Elizabeth Graham
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Michael McDonald
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Chintamani D Atreya
- Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD, USA
| | - Scott J MacGregor
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow, G1 1XW, Scotland, UK
| | - John G Anderson
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow, G1 1XW, Scotland, UK
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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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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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Nerandzic MM, Donskey CJ. A Quaternary Ammonium Disinfectant Containing Germinants Reduces Clostridium difficile Spores on Surfaces by Inducing Susceptibility to Environmental Stressors. Open Forum Infect Dis 2016; 3:ofw196. [PMID: 28066792 PMCID: PMC5198585 DOI: 10.1093/ofid/ofw196] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/14/2016] [Indexed: 01/05/2023] Open
Abstract
Exposing Clostridium difficile spores to germinants in a quaternary ammonium matrix was an effective method to reduce environmental contamination by sensitizing the spores, leaving them susceptible to ambient conditions and enhancing killing by acid, high-intensity visible light, and radiation.
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Affiliation(s)
| | - Curtis J Donskey
- Case Western Reserve University School of Medicine, Cleveland, Ohio;; Geriatric Research, Education and Clinical Center, Cleveland Veterans Affairs Medical Center, Ohio
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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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McKenzie K, Maclean M, Grant MH, Ramakrishnan P, MacGregor SJ, Anderson JG. The effects of 405 nm light on bacterial membrane integrity determined by salt and bile tolerance assays, leakage of UV-absorbing material and SYTOX green labelling. MICROBIOLOGY (READING, ENGLAND) 2016; 162:1680-1688. [PMID: 27499074 PMCID: PMC5068139 DOI: 10.1099/mic.0.000350] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 08/05/2016] [Indexed: 12/22/2022]
Abstract
Bacterial inactivation by 405 nm light is accredited to the photoexcitation of intracellular porphyrin molecules resulting in energy transfer and the generation of reactive oxygen species that impart cellular oxidative damage. The specific mechanism of cellular damage, however, is not fully understood. Previous work has suggested that destruction of nucleic acids may be responsible for inactivation; however, microscopic imaging has suggested membrane damage as a major constituent of cellular inactivation. This study investigates the membrane integrity of Escherichia coli and Staphylococcus aureus exposed to 405 nm light. Results indicated membrane damage to both species, with loss of salt and bile tolerance by S. aureus and E. coli, respectively, consistent with reduced membrane integrity. Increased nucleic acid release was also demonstrated in 405 nm light-exposed cells, with up to 50 % increase in DNA concentration into the extracellular media in the case of both organisms. SYTOX green fluorometric analysis, however, demonstrated contradictory results between the two test species. With E. coli, increasing permeation of SYTOX green was observed following increased exposure, with >500 % increase in fluorescence, whereas no increase was observed with S. aureus. Overall, this study has provided good evidence that 405 nm light exposure causes loss of bacterial membrane integrity in E. coli, but the results with S. aureus are more difficult to explain. Further work is required to gain greater understanding of the inactivation mechanism in different bacterial species, as there are likely to be other targets within the cell that are also impaired by the oxidative damage from photo-generated reactive oxygen species.
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Affiliation(s)
- Karen McKenzie
- Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), University of Strathclyde, 204 George Street, Glasgow, Scotland G1 1XW, UK
| | - Michelle Maclean
- Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), University of Strathclyde, 204 George Street, Glasgow, Scotland G1 1XW, UK
- Department of Biomedical Engineering, University of Strathclyde, Wolfson Centre, 106 Rottenrow, Glasgow, Scotland G4 0NW, UK
| | - M. Helen Grant
- Department of Biomedical Engineering, University of Strathclyde, Wolfson Centre, 106 Rottenrow, Glasgow, Scotland G4 0NW, UK
| | - Praveen Ramakrishnan
- Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), University of Strathclyde, 204 George Street, Glasgow, Scotland G1 1XW, UK
- Department of Biomedical Engineering, University of Strathclyde, Wolfson Centre, 106 Rottenrow, Glasgow, Scotland G4 0NW, UK
| | - Scott J. MacGregor
- Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), University of Strathclyde, 204 George Street, Glasgow, Scotland G1 1XW, UK
| | - John G. Anderson
- Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), University of Strathclyde, 204 George Street, Glasgow, Scotland G1 1XW, UK
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O'Donoghue B, NicAogáin K, Bennett C, Conneely A, Tiensuu T, Johansson J, O'Byrne C. Blue-Light Inhibition of Listeria monocytogenes Growth Is Mediated by Reactive Oxygen Species and Is Influenced by σB and the Blue-Light Sensor Lmo0799. Appl Environ Microbiol 2016; 82:4017-4027. [PMID: 27129969 PMCID: PMC4907204 DOI: 10.1128/aem.00685-16] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/19/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Listeria monocytogenes senses blue light via the flavin mononucleotide-containing sensory protein Lmo0799, leading to activation of the general stress response sigma factor SigB (σ(B)). In this study, we investigated the physiological response of this foodborne pathogen to blue light. We show that blue light (460 to 470 nm) doses of 1.5 to 2 mW cm(-2) cause inhibition of growth on agar-based and liquid culture media. The inhibitory effects are dependent on cell density, with reduced effects evident when high cell numbers are present. The addition of 20 mM dimethylthiourea, a scavenger of reactive oxygen species, or catalase to the medium reverses the inhibitory effects of blue light, suggesting that growth inhibition is mediated by the formation of reactive oxygen species. A mutant strain lacking σ(B) (ΔsigB) was found to be less inhibited by blue light than the wild type, likely indicating the energetic cost of deploying the general stress response. When a lethal dose of light (8 mW cm(-2)) was applied to cells, the ΔsigB mutant displayed a marked increase in sensitivity to light compared to the wild type. To investigate the role of the blue-light sensor Lmo0799, mutants were constructed that either had a deletion of the gene (Δlmo0799) or alteration in a conserved cysteine residue at position 56, which is predicted to play a pivotal role in the photocycle of the protein (lmo0799 C56A). Both mutants displayed phenotypes similar to the ΔsigB mutant in the presence of blue light, providing genetic evidence that residue 56 is critical for light sensing in L. monocytogenes Taken together, these results demonstrate that L. monocytogenes is inhibited by blue light in a manner that depends on reactive oxygen species, and they demonstrate clear light-dependent phenotypes associated with σ(B) and the blue-light sensor Lmo0799. IMPORTANCE Listeria monocytogenes is a bacterial foodborne pathogen that can cause life-threatening infections in humans. It is known to be able to sense and respond to visible light. In this study, we examine the effects of blue light on the growth and survival of this pathogen. We show that growth can be inhibited at comparatively low doses of blue light, and that at higher doses, L. monocytogenes cells are killed. We present evidence suggesting that blue light inhibits this organism by causing the production of reactive oxygen species, such as hydrogen peroxide. We help clarify the mechanism of light sensing by constructing a "blind" version of the blue-light sensor protein. Finally, we show that activation of the general stress response by light has a negative effect on growth, probably because cellular resources are diverted into protective mechanisms rather than growth.
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Affiliation(s)
- Beth O'Donoghue
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland, Galway, Galway, Ireland
| | - Kerrie NicAogáin
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland, Galway, Galway, Ireland
| | - Claire Bennett
- National Centre for Laser Applications, School of Physics, National University of Ireland, Galway, Galway, Ireland
| | - Alan Conneely
- National Centre for Laser Applications, School of Physics, National University of Ireland, Galway, Galway, Ireland
| | - Teresa Tiensuu
- Department of Molecular Biology, Molecular Infection Medicine, Sweden, and Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Jörgen Johansson
- Department of Molecular Biology, Molecular Infection Medicine, Sweden, and Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Conor O'Byrne
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland, Galway, Galway, Ireland
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Antibacterial Activity of Blue Light against Nosocomial Wound Pathogens Growing Planktonically and as Mature Biofilms. Appl Environ Microbiol 2016; 82:4006-4016. [PMID: 27129967 PMCID: PMC4907187 DOI: 10.1128/aem.00756-16] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/17/2016] [Indexed: 12/25/2022] Open
Abstract
The blue wavelengths within the visible light spectrum are intrinisically antimicrobial and can photodynamically inactivate the cells of a wide spectrum of bacteria (Gram positive and negative) and fungi. Furthermore, blue light is equally effective against both drug-sensitive and -resistant members of target species and is less detrimental to mammalian cells than is UV radiation. Blue light is currently used for treating acnes vulgaris and Helicobacter pylori infections; the utility for decontamination and treatment of wound infections is in its infancy. Furthermore, limited studies have been performed on bacterial biofilms, the key growth mode of bacteria involved in clinical infections. Here we report the findings of a multicenter in vitro study performed to assess the antimicrobial activity of 400-nm blue light against bacteria in both planktonic and biofilm growth modes. Blue light was tested against a panel of 34 bacterial isolates (clinical and type strains) comprising Acinetobacter baumannii, Enterobacter cloacae, Stenotrophomonas maltophilia, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Enterococcus faecium, Klebsiella pneumoniae, and Elizabethkingia meningoseptica. All planktonic-phase bacteria were susceptible to blue light treatment, with the majority (71%) demonstrating a ≥5-log10 decrease in viability after 15 to 30 min of exposure (54 J/cm2 to 108 J/cm2). Bacterial biofilms were also highly susceptible to blue light, with significant reduction in seeding observed for all isolates at all levels of exposure. These results warrant further investigation of blue light as a novel decontamination strategy for the nosocomial environment, as well as additional wider decontamination applications. IMPORTANCE Blue light shows great promise as a novel decontamination strategy for the nosocomial environment, as well as additional wider decontamination applications (e.g., wound closure during surgery). This warrants further investigation.
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Gunther NW, Phillips JG, Sommers C. The Effects of 405-nm Visible Light on the Survival of Campylobacter on Chicken Skin and Stainless Steel. Foodborne Pathog Dis 2016; 13:245-50. [DOI: 10.1089/fpd.2015.2084] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Nereus W. Gunther
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, U.S. Department of Agriculture, Agricultural Research Service, Wyndmoor, Pennsylvania
| | - John G. Phillips
- Agricultural Research Service–Retired, Eastern Regional Research Center, U.S. Department of Agriculture, Agricultural Research Service, Wyndmoor, Pennsylvania
| | - Christopher Sommers
- Food Safety and Intervention Technologies Research Unit, Eastern Regional Research Center, U.S. Department of Agriculture, Agricultural Research Service, Wyndmoor, Pennsylvania
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50
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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: 86] [Impact Index Per Article: 10.8] [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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