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Wu G, Wan Q, Lu J, Wen G. Impact of metal ions on PMS/Cl - disinfection efficacy: Enhancing or impeding microbial inactivation? THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 953:176087. [PMID: 39255943 DOI: 10.1016/j.scitotenv.2024.176087] [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: 07/17/2024] [Revised: 08/24/2024] [Accepted: 09/04/2024] [Indexed: 09/12/2024]
Abstract
Peroxymonosulfate (PMS) is an eco-friendly disinfectant gaining attention. This study examined the influence of metal ions (Co(II), Cu(II), Fe(II)) on PMS disinfection with chloride ions (Cl-) against waterborne microorganisms, encompassing both bacteria and fungal spores. The findings elucidated that metal ions augment the inactivation of bacteria in the PMS/Cl- system while concurrently impeding the inactivation of fungal spores. Specifically, the PMS/Co(II)/Cl- process increased E. coli inactivation rates by 2.25 and 2.75 times compared to PMS/Co(II) and PMS/Cl-, respectively. Conversely, PMS/Me(II)/Cl- generally exhibited a diminished inactivation capacity against the three fungal spores compared to PMS/Cl-, albeit surpassing the efficacy of PMS/Me(II). For instance, the inactivation levels of A. niger by PMS/Cl-, PMS/Cu(II)/Cl-, and PMS/Cu(II) are 4.47-log, 1.92-log, and 0.11-log, respectively. Notably, fungal spores demonstrated a substantially higher resistance to disinfectants compared to bacteria. Differences in microbial susceptibility were linked to cell wall structure, composition, antioxidant defenses, and reactive species generation, such as hydroxyl radicals (•OH), sulfate radicals (SO4•-), and reactive chlorine species (RCS). This study demonstrated the novel and unique phenomenon of metal ions' dual role in modulating the PMS/Cl- disinfection process, which has not been reported before and has important implications for the field of water treatment.
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Affiliation(s)
- Gehui Wu
- Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Provincial Field Scientific Observation and Research Station of Water Quality in Qinling Mountains, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Qiqi Wan
- Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Provincial Field Scientific Observation and Research Station of Water Quality in Qinling Mountains, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Jinsuo Lu
- Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Provincial Field Scientific Observation and Research Station of Water Quality in Qinling Mountains, Xi'an University of Architecture and Technology, Xi'an 710055, China; State Key Laboratory of Green Building, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Gang Wen
- Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Provincial Field Scientific Observation and Research Station of Water Quality in Qinling Mountains, Xi'an University of Architecture and Technology, Xi'an 710055, China; Collaborative Innovation Center of Water Pollution Control and Water Quality Security Assurance of Shaanxi Province, Xi'an University of Architecture and Technology, Xi'an 710055, China.
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Hu Z, Xu H, Cheng J, Zhang H, Zhao Y, Hu J, Sun Y, Huang L, Yao W, Yu Z, Xie Y. Catalyst-free regeneration of plasma-activated water via ultrasonic cavitation: Removing aggregation concealment of antibiotic-resistant bacteria with enhanced wastewater sustainability. JOURNAL OF HAZARDOUS MATERIALS 2024; 479:135705. [PMID: 39217933 DOI: 10.1016/j.jhazmat.2024.135705] [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: 07/04/2024] [Revised: 08/13/2024] [Accepted: 08/28/2024] [Indexed: 09/04/2024]
Abstract
Aggregation is a crucial factor in bacterial biofilm formation, and comprehending its properties is vital for managing waterborne antibiotic-resistant bacteria. In this study, we examined Methicillin-resistant Staphylococcus aureus (MRSA) cell aggregation under varying conditions and assessed the inactivation efficiency of a novel disinfection method, micro-nano bubbles plasma-activated water via ultrasonic stirring cavitation (MPAW-US), on aggregated MRSA cells. Aggregation efficiency increased over time and at low salt concentrations but diminished at higher concentrations. Elevated MRSA cell aggregation in actual water samples represented significant real-life biohazard risks. Unlike conventional disinfection, MPAW-US treatment exhibited minimal change in the inactivation rate constant despite protective outer layers. Enhanced inactivation efficiency results from the synergistic effects of increased intracellular oxidative stress damage and extracellular substance disruption, triggered by ultrasound-activated micro-nano bubbles that improve PAW reactivity and applicability. This approach neither induced MRSA cross-resistance to unfavorable conditions nor increased toxicity or regrowth potential of aggregative MRSA, utilizing ATP levels as potential regrowth capability indicators. Ultimately, this energy-efficient disinfection technology functions effectively across diverse temperature ranges, showcasing exceptional sterilization and nutritional bean sprout production after cyclic filtering, thereby promoting wastewater sustainability amidst carbon emission concerns.
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Affiliation(s)
- Zhenyang Hu
- State Key Laboratory of Food Science and Resources, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; School of Food Science and Technology, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, China
| | - Hongwen Xu
- State Key Laboratory of Food Science and Resources, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; School of Food Science and Technology, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, China
| | - Jun Cheng
- State Key Laboratory of Food Science and Resources, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; School of Food Science and Technology, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, China
| | - Huan Zhang
- State Key Laboratory of Food Science and Resources, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; School of Food Science and Technology, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, China
| | - Yali Zhao
- State Key Laboratory of Food Science and Resources, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; School of Food Science and Technology, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, China
| | - Jian Hu
- Key Laboratory of Chinese Cuisine Intangible Cultural Heritage Technology Inheritance, Ministry of Culture and Tourism, College of Tourism and Culinary Science, Yangzhou University, Yangzhou 225127, China
| | - Yingying Sun
- Research Institute, Centre Testing International Group Co., Ltd., Shenzhen 518000, China
| | - Lijun Huang
- Wuxi Food Safety Inspection and Test Center, 35-210 Changjiang South Road, Wuxi 214142, Jiangsu Province, China
| | - Weirong Yao
- State Key Laboratory of Food Science and Resources, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; School of Food Science and Technology, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, China
| | - Zhilong Yu
- State Key Laboratory of Food Science and Resources, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; School of Food Science and Technology, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, China
| | - Yunfei Xie
- State Key Laboratory of Food Science and Resources, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; School of Food Science and Technology, Jiangnan University, No.1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, China.
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Ghimire B, Pendyala B, Patras A, Baysal-Gurel F. Evaluating UV-C Sensitivity of Calonectria pseudonaviculata in Model Buffer Solution Using a UV-C Light-Emitting-Diode System. PLANT DISEASE 2024; 108:2663-2667. [PMID: 38720539 DOI: 10.1094/pdis-03-24-0618-sc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/29/2024]
Abstract
Calonectria pseudonaviculata, responsible for boxwood blight, produces sticky conidia that pose a contamination risk in boxwood production via cross-contamination from tools, equipment, and other resources. This study evaluated UV-C light-emitting-diode (LED) irradiation (263 to 287 nm) as a disinfection method by examining its effectiveness in inactivating conidia and determining the UV-C sensitivity. Conidial suspensions were exposed to quantifiable UV-C doses under a dynamic stirring condition. Average volumetric intensity was quantified by accounting for UV gradients and UV dose was calculated as a product of average fluence rate (mW⋅cm-2) and exposure time (s). UV-C irradiation effectively inactivated the tested pathogen following log-linear + shoulder kinetics as identified by parameters of goodness of model fit (i.e., high R2 and low root mean square error [RMSE] values). The model predicted the UV sensitivity of C. pseudonaviculata conidia as 46.6 mJ⋅cm-2 per log. A total of 2.04 log reductions of the population could be obtained by an exposure of 60 mJ⋅cm-2 of UV-C dose. The calculated decimal reduction dose (D10) was 13.53 ± 0.98 mJ⋅cm-2 (R2 = 0.97, RMSE = 0.14), inactivation rate constant (Kmax) = 0.17 ± 0.01, and shoulder length = 33.06 ± 1.81 mJ⋅cm-2. These findings indicate that UV-C irradiation could be a viable option for disinfecting tools, equipment, and possibly propagation cuttings in nurseries.
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Affiliation(s)
- Bhawana Ghimire
- Department of Agricultural Sciences and Engineering, College of Agriculture, Tennessee State University, Otis L. Floyd Nursery Research Center, McMinnville, TN 37110
| | - Brahmaiah Pendyala
- Department of Food and Animal Sciences, College of Agriculture, Tennessee State University, Nashville, TN 37209
| | - Ankit Patras
- Department of Food and Animal Sciences, College of Agriculture, Tennessee State University, Nashville, TN 37209
| | - Fulya Baysal-Gurel
- Department of Agricultural Sciences and Engineering, College of Agriculture, Tennessee State University, Otis L. Floyd Nursery Research Center, McMinnville, TN 37110
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Rito B, Matos L, Proença DN, Morais PV. Kinetics of inactivation of bacteria responsible for infections in hospitals using UV-LED. Heliyon 2024; 10:e30738. [PMID: 38765034 PMCID: PMC11096922 DOI: 10.1016/j.heliyon.2024.e30738] [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: 01/03/2024] [Revised: 04/30/2024] [Accepted: 05/03/2024] [Indexed: 05/21/2024] Open
Abstract
Controlling the microbial load in the environment is crucial to prevent the spread of organisms. The continuous spread of nosocomial infections in hospital facilities and the emergence of the coronavirus (COVID-19) highlighted the importance of disinfection processes in health safety. This work aimed to evaluate the effectiveness of LED-based disinfection lamps on bacteria from the ESKAPEE group and virus phage in vitro inactivation to be applied in hospital environments and health facilities disinfection. This study evaluated the effect of different UV wavelengths (275 nm, 280 nm (UVC), 310 nm (UVB) and 340 nm (UVA)) on the disinfection process of various microbial indicators including E. coli, S. aureus, P. aeruginosa, B. subtilis and Bacteriophage lambda DSM 4499. Exposure time (5 min-30 min), exposure distance (0.25 m and 0.5 m) and surface materials (glass, steel, and polished wood) were evaluated on the disinfection efficiency. Furthermore, the study determined the recovery capacity of each species after UV damage. UVC-LED lamps could inactivate 99.99 % of microbial indicators after 20 min exposures at a 0.5 m distance. The exposure time needed to completely inactivate E. coli, S. aureus, P. aeruginosa, B. subtilis and Bacteriophage lambda DSM 4499 can be decreased by reducing the exposure distance. UVB-LED and UVA-LED lamps were not able to promote a log reduction of 4 and were not effective on B. subtilis or bacteriophage lambda DSM 4499 inactivation. Thus, only UVC-LED lamps were tested on the decontamination of different surface materials, which was successful. P. aeruginosa showed the ability to recover from UV damage, but its inactivation rate remains 99.99 %, and spores from B. subtilis were not completely inactivated. Nevertheless, the inactivation rate of these indicators remained at 99.99 % with 24 h incubation after UVC irradiation. UVC-LED lamps emitting 280 nm were the most indicated to disinfect surfaces from microorganisms usually found in hospital environments.
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Affiliation(s)
- Beatriz Rito
- University of Coimbra, Centre for Mechanical Engineering, Materials and Processes, ARISE, Department of Life Sciences, Calcada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Leonor Matos
- University of Coimbra, Centre for Mechanical Engineering, Materials and Processes, ARISE, Department of Life Sciences, Calcada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Diogo N. Proença
- University of Coimbra, Centre for Mechanical Engineering, Materials and Processes, ARISE, Department of Life Sciences, Calcada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Paula V. Morais
- University of Coimbra, Centre for Mechanical Engineering, Materials and Processes, ARISE, Department of Life Sciences, Calcada Martim de Freitas, 3000-456, Coimbra, Portugal
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Memic S, Kaple CE, Cadnum JL, Donskey CJ. Evaluation of an Automated Wall-mounted Far Ultraviolet-C Light Technology for Continuous or Intermittent Decontamination of Candida auris on Surfaces. Pathog Immun 2024; 9:156-167. [PMID: 38779368 PMCID: PMC11110956 DOI: 10.20411/pai.v9i1.683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 05/08/2024] [Indexed: 05/25/2024] Open
Abstract
Background Technologies that provides safe and effective decontamination of surfaces and equipment between episodes of manual cleaning could be an important advance in efforts to prevent transmission of the emerging fungal pathogen Candida auris. Methods We tested the efficacy of a novel wall-mounted far ultraviolet-C (UV-C) light technology that delivers far UV-C, when people are not detected within the field of illumination, against C. auris isolates from clades I, II, III, and IV using a quantitative disk carrier test method. In an equipment room, we examined the efficacy of the technology in reducing an isolate of C. auris from clade IV inoculated on multiple sites on portable devices. Results The far UV-C technology reduced isolates from all 4 clades of C. auris by >3 log10 colony-forming units (CFU) aſter an 8-hour exposure on steel disks. For the clade IV isolate, similar reductions were achieved on glass and plastic carriers. In the equipment room, the technology reduced C. auris inoculated on multiple sites on portable equipment by >2 log10 CFU in 4 hours. Conclusions The far UV-C technology could be useful for decontamination of surfaces and equipment between episodes of manual cleaning. Additional studies are needed to evaluate the use of the technology in clinical settings.
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Affiliation(s)
- Samir Memic
- Department of Systems Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio
| | - Claire E. Kaple
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Jennifer L. Cadnum
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio
| | - Curtis J. Donskey
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio
- Geriatric Research, Education, and Clinical Center, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio
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Zhang Z, Zhang H, Wu G, Xu X, Cao R, Wan Q, Xu H, Wang J, Huang T, Wen G. The aggregation characteristics of Aspergillus spores under various conditions and the impact on LPUV inactivation: Comparisons with chlorine-based disinfection. WATER RESEARCH 2024; 253:121323. [PMID: 38377927 DOI: 10.1016/j.watres.2024.121323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 01/30/2024] [Accepted: 02/14/2024] [Indexed: 02/22/2024]
Abstract
Aggregation is the primary step prior to fungal biofilm development. Understanding the attributes of aggregation is of great significance to better control the emergence of waterborne fungi. In this study, the aggregation of Aspergills spores (A. flavus and A. fumigatus) under various salt, culture medium, and humic acid (HA) conditions was investigated for the first time, and the inactivation via low-pressure ultraviolet (LPUV) upon aggregated Aspergillus spores was also presented. The aggregation efficiency and size of aggregates increased over time and at low salt (NaCl and CaCl2) concentration (10 mM) while decreasing with the continuous increase of salt concentration (100 and 200 mM). Increasing the concentration of culture medium and HA promoted the aggregation of fungal spores. Spores became hydrated, swelled, and secreted more viscous substances during the growth period, which accelerated the aggregation process. Results also suggested that fungal spores aggregated more easily in actual water, posing a high risk of biohazard in real-life scenarios. Inactivation efficiency by LPUV decreased with higher aggregation degrees due to the protection from the damaged spores on the outer layer and the shielding of pigments in the cell wall. Compared to chlorine-based disinfection, the aggregation resulted in the extension of shoulder length yet neglectable change of inactivation rate constant under LPUV treatment. Further investigation of cell membrane integrity and intracellular reactive oxygen species was conducted to elucidate the difference in mechanisms between various techniques. This study provides insight into the understanding and controlling of the aggregation of fungal spores.
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Affiliation(s)
- Zhenghong Zhang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Huan Zhang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Gehui Wu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Xiangqian Xu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Ruihua Cao
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Qiqi Wan
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Huining Xu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Jingyi Wang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Tinglin Huang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Gang Wen
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China.
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Wang JJ, Zhou YY, Xiang JL, Du HS, Zhang J, Zheng TG, Liu M, Ye MQ, Chen Z, Du Y. Disinfection of wastewater by a complete equipment based on a novel ultraviolet light source of microwave discharge electrodeless lamp: Characteristics of bacteria inactivation, reactivation and full-scale studies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 917:170200. [PMID: 38296065 DOI: 10.1016/j.scitotenv.2024.170200] [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: 11/10/2023] [Revised: 01/14/2024] [Accepted: 01/14/2024] [Indexed: 02/06/2024]
Abstract
Ultraviolet (UV) light is widely used for wastewater disinfection. Traditional electrode-excited UV lamps, such as low-pressure mercy lamps (LPUV), encounter drawbacks like electrode aging and rapid light attenuation. A novel UV source of microwave discharge electrodeless lamp (MDEL) has aroused attention, yet its disinfection performance is unclear and still far from practical application. Here, we successfully developed a complete piece of equipment based on MDELs and achieved the application for disinfection in wastewater treatment plants (WWTPs). The light emitted by an MDEL (MWUV) shared a spectrum similar to that of LPUV, with the main emission wavelength at 254 nm. The inactivation rate of Gram-negative E. coli by MWUV reached 4.5 log at an intensity of 1.6 mW/cm2 and a dose of 20 mJ/cm2. For Gram-positive B. subtilis, an MWUV dose of 50 mJ/cm2 and a light intensity of 1.2 mW/cm2 reached an inactivation rate of 3.4 log. A higher MWUV intensity led to a better disinfection effect and a lower photoreactivation rate of E. coli. When inactivated by MWUV with an intensity of 1.2 mW/cm2 and a dose of 16 mJ/cm2, the maximum photoreactivation rate and reactivation rate constant Kmax of E. coli were 0.63 % and 0.11 % h-1 respectively. Compared with the photoreactivation, the dark repair of E. coli was insignificant. The full-scale application of the MDEL equipment was conducted in two WWTPs (10,000 m3/d and 15,000 m3/d). Generally 2-3 log inactivation rates of fecal coliforms in secondary effluent were achieved within 5-6 s contact time, and the disinfected effluent met the emission standard (1000 CFU/L). This study successfully applied MDEL for disinfection in WWTPs for the first time and demonstrated that MDEL has broad application prospects.
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Affiliation(s)
- Jun-Jie Wang
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Yun-Yi Zhou
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Jue-Lin Xiang
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Hai-Sheng Du
- Sichuan Macyouwei Environmental Protection Technology Co., Ltd, Chengdu 610000, China
| | - Jin Zhang
- Sichuan Science City Tianren Environmental Protection Co., Ltd, Mianyang 621022, China
| | - Ti-Gang Zheng
- Sichuan Science City Tianren Environmental Protection Co., Ltd, Mianyang 621022, China
| | - Min Liu
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Ming-Qi Ye
- Everbright Water (Shenzhen) Limited, Shenzhen 518000, China
| | - Zhuo Chen
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Ye Du
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China.
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Adam C, Colin M, Stock R, Weiss L, Gangloff SC. UVC Box: An Effective Way to Quickly Decontaminate Healthcare Facilities' Wheelchairs. Life (Basel) 2024; 14:256. [PMID: 38398765 PMCID: PMC10890712 DOI: 10.3390/life14020256] [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: 01/09/2024] [Revised: 02/10/2024] [Accepted: 02/12/2024] [Indexed: 02/25/2024] Open
Abstract
Disinfection in the hospital environment remains challenging, especially for wide and structurally complex objects such as beds or wheelchairs. Indeed, the regular disinfection of these objects with chemicals is manually carried out by healthcare workers and is fastidious and time-consuming. Alternative antibacterial techniques were thus proposed in the past decades, including the use of naturally antimicrobial UVC. Here, the antibacterial efficiency of a large UVC box built to accommodate wheelchairs was investigated through testing bacterial burden reductions on various parts of a wheelchair, with various support types and with several treatment durations. The results demonstrate a time-dependent antibacterial effect, with a strong burden reduction at only five minutes of treatment (>3-log median reduction in Escherichia coli and Staphylococcus epidermidis). The UVC flux and residual bacterial burden both significantly varied depending on the spatial location on the wheelchair. However, the nature of the support impacted the antibacterial efficiency even more, with residual bacterial burdens being the lowest on rigid materials (steel, plastics) and being the highest on tissue. On metallic samples, the nature of the alloy and surface treatment had various impacts on the antibacterial efficiency of the UVC. This study highlights the efficiency of the tested UVC box to efficiently and quickly decontaminate complex objects such as wheelchairs, but also gives rise to the warning to focus on rigid materials and avoid porous materials in the conception of objects, so as to ensure the efficiency of UVC decontamination.
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Affiliation(s)
- Cloé Adam
- Université de Reims Champagne-Ardenne, UR 4691 Biomatériaux et Inflammation en Site Osseux (BIOS), UFR de Pharmacie, SFR CAP-Santé, 51 rue Cognacq Jay, 51100 Reims, France (S.C.G.)
| | - Marius Colin
- Université de Reims Champagne-Ardenne, UR 4691 Biomatériaux et Inflammation en Site Osseux (BIOS), UFR de Pharmacie, SFR CAP-Santé, 51 rue Cognacq Jay, 51100 Reims, France (S.C.G.)
| | - Romuald Stock
- Université de Lorraine, LCOMS, EA7306 Lorraine, France;
| | - Laurent Weiss
- Université de Lorraine LEM 3, UMR CNRS 7239, 7 Rue Félix Savart, 57073 Metz, France;
| | - Sophie C. Gangloff
- Université de Reims Champagne-Ardenne, UR 4691 Biomatériaux et Inflammation en Site Osseux (BIOS), UFR de Pharmacie, SFR CAP-Santé, 51 rue Cognacq Jay, 51100 Reims, France (S.C.G.)
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9
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Bai Y, Zhou Y, Chang R, Zhou Y, Hu X, Hu J, Yang C, Chen J, Zhang Z, Yao J. Investigating synergism and mechanism during sequential inactivation of Staphylococcus aureus with ultrasound followed by UV/peracetic acid. JOURNAL OF HAZARDOUS MATERIALS 2024; 462:132609. [PMID: 37844493 DOI: 10.1016/j.jhazmat.2023.132609] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 10/18/2023]
Abstract
This study explored the inactivation of Staphylococcus aureus (S. aureus) by ultrasound (US) and peracetic acid (PAA) coupling with UV simultaneously (US/PAA/UV) or sequentially (US→PAA/UV) for the strengthened disinfection. The result showed that US→PAA/UV system had excellent inactivation performance with 5.05-log in a short time. Besides US, UV, PAA and free radicals, the contribution of the synergy of all components to the entire disinfection were obvious under US→PAA/UV system. The inactivation performance of S. aureus significantly decreased with the increase of humic acid (HA) concentration and pH; however, the rising temperature contributes to the enhancement of the inactivation efficiency under the US→PAA/UV system. The disinfection mechanism includes a decrease of cell agglomeration, a loss of intracellular substance, and changes of cell structure and membrane permeability, as evidenced through a nanoparticle size analyzer, scanning electron microscope (SEM), transmission electron microscope (TEM) and laser confocal microscopy (LSCM). Furthermore, the inactivation efficiency of the US→PAA/UV system for the total bacteria from actual sewage (the untreated inflow) was high, which reached 3.86-log. In general, the pretreatment of US combined with UV/PAA showed a promising application in the rapid disinfection of sewage.
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Affiliation(s)
- Yun Bai
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Yuanhang Zhou
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Ruiting Chang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Yingying Zhou
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Xueli Hu
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Jiawei Hu
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Chuanyao Yang
- Analysis and Testing Center, Chongqing University, Chongqing 400045, China
| | - Jiabo Chen
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Zhi Zhang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; College of Environment and Ecology, Chongqing University, Chongqing 400045, China.
| | - Juanjuan Yao
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; College of Environment and Ecology, Chongqing University, Chongqing 400045, China.
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10
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Shekhawat SS, Saini P, Upadhyay A, Pareek N, Arora S, Gupta AB, Vivekanand V. Treatment of clinical laboratory sewage using a decentralized treatment unit and risk reduction for its reuse in irrigation using hybrid disinfection. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 344:118684. [PMID: 37536236 DOI: 10.1016/j.jenvman.2023.118684] [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: 04/03/2023] [Revised: 06/08/2023] [Accepted: 07/25/2023] [Indexed: 08/05/2023]
Abstract
The disinfection efficacy of standalone chlorine, UV and their combined approach (hybrid) was investigated for the coliform removal in BioKube 1 and 2 treated effluents collected from different environmental settings of clinical and domestic wastes. Chlorine and UV disinfection were applied to BioKube treated wastewater with doses from 0 to 4 mg L-1 and 0-166 mJ cm-2 respectively. Combined disinfection strategies were designed to reduce the dose of chlorine and UV and to exploit the synergistic effect of them. The culturable coliforms were enumerated in treated wastewater sample (control), immediately after (reduction), and 24 h post disinfections (regrowth) using culture media plating and colilert-18 media. Both the BioKube systems (1 and 2) were effective in achieving the strict norms of physicochemical parameters, but not following the coliform counts of treated effluent for reuse in irrigation. A hybrid strategy of chlorine followed by UV was found to be the most effective among various standalone and combination approaches for the removal of coliforms (>4 log ER or <1000 CFU/100 mL) from both the treated effluents. However, coliform present in treated effluent of BioKube 1 were resisting (regrowth) against all kind of applied disinfectants except chlorine followed by UV dose at or more than 0.5 mg L-1 + 41 mJ cm-2. Limited reports are available on hybrid disinfection approaches with decentralized packaged sewage treatment units and this study would help to adopt as an effective tertiary treatment strategy for reuse of treated sewage for irrigation while ensuring public health safety.
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Affiliation(s)
- Sandeep Singh Shekhawat
- Centre for Energy and Environment, Malaviya National Institute of Technology Jaipur, JLN Marg, Jaipur, 302017, India; Department of Mechanical-Mechatronics Engineering, The LNM Institute of Information Technology, Jaipur, 302031, India
| | - Pankaj Saini
- Department of Civil Engineering, Malaviya National Institute of Technology Jaipur, JLN Marg, Jaipur, 302017, India
| | - Aparna Upadhyay
- Department of Civil Engineering, Malaviya National Institute of Technology Jaipur, JLN Marg, Jaipur, 302017, India
| | - Nidhi Pareek
- Department of Microbiology, School of Life Sciences, Central University of Rajasthan Bandarsindri, Ajmer, Kishangarh, Rajasthan, 305801, India
| | - Sudipti Arora
- B. Lal Institute of Biotechnology, Jaipur, Rajasthan 302017, India
| | - Akhilendra Bhushan Gupta
- Department of Civil Engineering, Malaviya National Institute of Technology Jaipur, JLN Marg, Jaipur, 302017, India
| | - Vivekanand Vivekanand
- Centre for Energy and Environment, Malaviya National Institute of Technology Jaipur, JLN Marg, Jaipur, 302017, India.
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11
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Shi YG, Chen WX, Zheng MZ, Zhao YX, Wang YR, Chu YH, Du ST, Shi ZY, Gu Q, Chen JS. Ultraefficient OG-Mediated Photodynamic Inactivation Mechanism for Ablation of Bacteria and Biofilms in Water Augmented by Potassium Iodide under Blue Light Irradiation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:13672-13687. [PMID: 37671932 DOI: 10.1021/acs.jafc.3c03182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
While photodynamic inactivation (PDI) has emerged as a novel sterilization strategy for drinking water treatment that recently attracted tremendous attention, its efficiency needs to be further improved. In this study, we aimed to clarify the ultraefficient mechanism by which potassium iodide (KI) potentiates octyl gallate (OG)-mediated PDI against bacteria and biofilms in water. When OG (0.15 mM) and bacteria were exposed to blue light (BL, 420 nm, 210 mW/cm2), complete sterilization (>7.5 Log cfu/mL of killing) was achieved by the addition of KI (250 mM) within only 5 min (63.9 J/cm2). In addition, at lower doses of OG (0.1 mM) with KI (100 mM), the biofilm was completely eradicated within 10 min (127.8 J/cm2). The KI-potentiated mechanism involves in situ rapid photogeneration of a multitude of reactive oxygen species, especially hydroxyl radicals (•OH), reactive iodine species, and new photocytocidal substances (quinone) by multiple photochemical pathways, which led to the destruction of cell membranes and membrane proteins, the cleavage of genomic DNA and extracellular DNA within biofilms, and the degradation of QS signaling molecules. This multitarget synergistic strategy provided new insights into the development of an environmentally friendly, safe, and ultraefficient photodynamic drinking water sterilization technology.
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Affiliation(s)
- Yu-Gang Shi
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035 Zhejiang, China
- Key Laboratory for Food Microbial Technology of Zhejiang Province, Zhejiang Gongshang University, Hangzhou 310035 Zhejiang, China
| | - Wen-Xuan Chen
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035 Zhejiang, China
| | - Mei-Zhi Zheng
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035 Zhejiang, China
| | - Yue-Xin Zhao
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035 Zhejiang, China
| | - Yi-Ran Wang
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035 Zhejiang, China
| | - Yen-Ho Chu
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chiayi 62102 Taiwan, China
| | - Shao-Ting Du
- Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou 310015, China
| | - Ze-Yu Shi
- Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou 310015, China
| | - Qing Gu
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035 Zhejiang, China
- Key Laboratory for Food Microbial Technology of Zhejiang Province, Zhejiang Gongshang University, Hangzhou 310035 Zhejiang, China
| | - Jian-She Chen
- School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035 Zhejiang, China
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12
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Abkar L, Zimmermann K, Dixit F, Kheyrandish A, Mohseni M. COVID-19 pandemic lesson learned- critical parameters and research needs for UVC inactivation of viral aerosols. JOURNAL OF HAZARDOUS MATERIALS ADVANCES 2022; 8:100183. [PMID: 36619826 PMCID: PMC9553962 DOI: 10.1016/j.hazadv.2022.100183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/28/2022] [Accepted: 10/10/2022] [Indexed: 11/28/2022]
Abstract
The COVID-19 pandemic highlighted public awareness of airborne disease transmission in indoor settings and emphasized the need for reliable air disinfection technologies. This increased awareness will carry in the post-pandemic era along with the ever-emerging SARS-CoV variants, necessitating effective and well-defined protocols, methods, and devices for air disinfection. Ultraviolet (UV)-based air disinfection demonstrated promising results in inactivating viral bioaerosols. However, the reported data diversity on the required UVC doses has hindered determining the best UVC practices and led to confusion among the public and regulators. This article reviews available information on critical parameters influencing the efficacy of a UVC air disinfection system and, consequently, the required dose including the system's components as well as operational and environmental factors. There is a consensus in the literature that the interrelation of humidity and air temperature has a significant impact on the UVC susceptibility, which translate to changing the UVC efficacy of commercialized devices in indoor settings under varying conditions. Sampling and aerosolization techniques reported to have major influence on the result interpretation and it is recommended to use several sampling methods simultaneously to generate comparable and conclusive data. We also considered the safety concerns and the potential safe alternative of UVC, far-UVC. Finally, the gaps in each critical parameter and the future research needs of the field are represented. This paper is the first step to consolidating literature towards developing a standard validation protocol for UVC air disinfection devices which is determined as the one of the research needs.
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Key Words
- Aerosolization of pathogens
- Air sampling methods
- Airborne transmission
- CDC, centre for disease control and prevention (USA)
- CMD, count median diameter
- DNA, deoxyribonucleic acid
- DSB, double strand break
- Far-UVC
- Far-UVC, ultraviolet irradiation in the ‘far’ range of 200–230 nm
- GTC, growth tube collectors
- LED, light emitting diode
- LPUV, low-pressure ultraviolet lamp
- NIOSH, national institute for occupational safety and health
- PBS, phosphate buffered saline
- PRRS, porcine reproductive and respiratory syndrome
- Particle size distribution
- REL, recommended exposure limit
- RH, relative humidity
- RNA, ribonucleic acid
- ROS, reactive oxygen species
- SARS-CoV-2, severe acute respiratory syndrome coronavirus-2
- SSB, single strand break
- Suspending media
- UV, ultraviolet irradiation
- UV-LED, light emitting diode in the ultraviolet range
- UVC, ultraviolet irradiation in the ‘C’, or germicidal, spectrum from 200 to 290 nm
- UVGI, ultraviolet germicidal irradiation
- Viral UVC susceptibility
- dsDNA, double-stranded deoxyribonucleic acid
- ssRNA, single-stranded ribonucleic acid
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13
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The biofilm life cycle: expanding the conceptual model of biofilm formation. Nat Rev Microbiol 2022; 20:608-620. [PMID: 35922483 PMCID: PMC9841534 DOI: 10.1038/s41579-022-00767-0] [Citation(s) in RCA: 345] [Impact Index Per Article: 172.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2022] [Indexed: 01/18/2023]
Abstract
Bacterial biofilms are often defined as communities of surface-attached bacteria and are typically depicted with a classic mushroom-shaped structure characteristic of Pseudomonas aeruginosa. However, it has become evident that this is not how all biofilms develop, especially in vivo, in clinical and industrial settings, and in the environment, where biofilms often are observed as non-surface-attached aggregates. In this Review, we describe the origin of the current five-step biofilm development model and why it fails to capture many aspects of bacterial biofilm physiology. We aim to present a simplistic developmental model for biofilm formation that is flexible enough to include all the diverse scenarios and microenvironments where biofilms are formed. With this new expanded, inclusive model, we hereby introduce a common platform for developing an understanding of biofilms and anti-biofilm strategies that can be tailored to the microenvironment under investigation.
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UV tolerance of Lactococcus lactis 936-type phages: Impact of wavelength, matrix, and pH. Int J Food Microbiol 2022; 378:109824. [DOI: 10.1016/j.ijfoodmicro.2022.109824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 06/17/2022] [Accepted: 06/26/2022] [Indexed: 11/22/2022]
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15
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Ichikawa S, Okazaki M, Okamura M, Nishimura N, Miyake H. Rare UV-resistant cells in clonal populations of Escherichia coli. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2022; 231:112448. [PMID: 35490545 DOI: 10.1016/j.jphotobiol.2022.112448] [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: 01/17/2022] [Revised: 04/11/2022] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
Water disinfection is one of the most important applications of ultraviolet light-emitting diodes (UV-LEDs), though bacterial regrowth remains a serious problem. In this study, we showed that UV-resistant cells, though rare, exist in an Escherichia coli clonal population. The UV-resistance of stationary phase cells was higher than that of exponential phase cells. Regrowth cell populations showed identical UV sensitivity before and after UV treatment, indicating that UV resistance is not acquired genetically, but is generated stochastically. The characteristics of these UV-resistant cells are similar to those of non-heritable antibiotic-resistant cells, termed persisters. The induction of persister formation increased the number of viable cells after UV treatment. The toxin-antitoxin system gene hipA (high persistence A) is a key factor in persister cell formation. We observed that hipA was strongly expressed in the stationary phase cells, while regrowth cells after UV treatment lost hipA expression, suggesting that the regrowth cells lost their persistence. Compared to UV batch radiation, we demonstrated that intermittent UV irradiation, which included the induction of regrowth between UV treatments, significantly reduced the number of viable E. coli cells.
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Affiliation(s)
- Shunsuke Ichikawa
- Faculty of Education, Mie University, 1577 Kurimamachiya-cho Tsu, Mie 514-8507, Japan.
| | - Mika Okazaki
- Strategic Planning Office for Regional Revitalization, Mie University, 1577 Kurimamachiya-cho Tsu, Mie 514-8507, Japan
| | - Mina Okamura
- Strategic Planning Office for Regional Revitalization, Mie University, 1577 Kurimamachiya-cho Tsu, Mie 514-8507, Japan
| | - Norihiro Nishimura
- Graduate School of Regional Innovation Studies, Mie University, 1577 Kurimamachiya-cho Tsu, Mie 514-8507, Japan
| | - Hideto Miyake
- Graduate School of Regional Innovation Studies, Mie University, 1577 Kurimamachiya-cho Tsu, Mie 514-8507, Japan
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16
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Nicolau T, Gomes Filho N, Padrão J, Zille A. A Comprehensive Analysis of the UVC LEDs' Applications and Decontamination Capability. MATERIALS (BASEL, SWITZERLAND) 2022; 15:2854. [PMID: 35454546 PMCID: PMC9028096 DOI: 10.3390/ma15082854] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/08/2022] [Accepted: 04/11/2022] [Indexed: 01/27/2023]
Abstract
The application of light-emitting diodes (LEDs) has been gaining popularity over the last decades. LEDs have advantages compared to traditional light sources in terms of lifecycle, robustness, compactness, flexibility, and the absence of non-hazardous material. Combining these advantages with the possibility of emitting Ultraviolet C (UVC) makes LEDs serious candidates for light sources in decontamination systems. Nevertheless, it is unclear if they present better decontamination effectiveness than traditional mercury vapor lamps. Hence, this research uses a systematic literature review (SLR) to enlighten three aspects: (1) UVC LEDs' application according to the field, (2) UVC LEDs' application in terms of different biological indicators, and (3) the decontamination effectiveness of UVC LEDs in comparison to conventional lamps. UVC LEDs have spread across multiple areas, ranging from health applications to wastewater or food decontamination. The UVC LEDs' decontamination effectiveness is as good as mercury vapor lamps. In some cases, LEDs even provide better results than conventional mercury vapor lamps. However, the increase in the targets' complexity (e.g., multilayers or thicker individual layers) may reduce the UVC decontamination efficacy. Therefore, UVC LEDs still require considerable optimization. These findings are stimulating for developing industrial or final users' applications.
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Affiliation(s)
- Talita Nicolau
- 2C2T-Centre for Textile Science and Technology, University of Minho, 4800-058 Guimaraes, Portugal
| | - Núbio Gomes Filho
- School of Economics and Management, University of Minho, 4710-057 Braga, Portugal
| | - Jorge Padrão
- 2C2T-Centre for Textile Science and Technology, University of Minho, 4800-058 Guimaraes, Portugal
| | - Andrea Zille
- 2C2T-Centre for Textile Science and Technology, University of Minho, 4800-058 Guimaraes, Portugal
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17
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Peng Y, Chen Z, Li Y, Wang Y, Ye C, Xu J, Zhang S. Bacteriostasis and cleaning effect of trace ozone replacing personal care products. ENVIRONMENTAL TECHNOLOGY 2022:1-14. [PMID: 35099355 DOI: 10.1080/09593330.2022.2036818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Ozone is widely used to inactivate bacteria, fungi, and viruses. In recent years, the treatment of itchy skin diseases (eczema and atopic dermatitis) using trace ozone has also received attention. However, the feasibility of using trace ozone to replace personal care products (PCPs) has rarely been analyzed. In this study, the applicability of trace ozone was evaluated in terms of its efficiency for microbial inactivation in three types of skin microbiomes, cleaning performance on simulated human hair and epidermis, safety for simulated human hair, and contribution to emission reduction. The results revealed that at a 10:1 ratio of ozonated water to bacterial suspension, the inactivation ratios of Malassezia, C. albicans, and S. epidermidis reached 99.63%, 83.47%, and 100%, respectively. In addition, the cleaning performance of an ozone solution (0.4 mg/L) for simulated human skin contaminated with carbon black and sebum could reach 95.89% and 95.63%, respectively, with 5 min of washing. The average scores were 0.40 and 0.37 after 5 min and 10 min of ozone treatments, respectively, indicating that trace ozone does not significantly damage simulated human hair. Results also revealed that the total emissions of COD, TP, and TN would be reduced by 1.29×106, 3.55×103, and 3.63×103 mg/ (household · year), respectively, if PCPs are replaced by trace ozone. In short, our findings indicate that trace ozone is a potential alternative to PCPs. By replacing PCPs with trace ozone, the use of synthetic chemical products can be reduced and carbon emissions from oil extraction can be countered.
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Affiliation(s)
- Yanyan Peng
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, PR People's Republic of China
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, PR People's Republic of China
| | - Zhou Chen
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, PR People's Republic of China
| | - Yanzeng Li
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, PR People's Republic of China
| | - Yuantao Wang
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, PR People's Republic of China
| | - Chengsong Ye
- Xiamen University, Xiamen, PR People's Republic of China
| | - Junming Xu
- Confosin Technology Co. Ltd., Dongguan, PR People's Republic of China
| | - Shenghua Zhang
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, PR People's Republic of China
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