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Photocatalysis offers a direct, yet robust, approach to eradicate pathogenic bacteria. However, the practical implementation of photocatalytic disinfection faces a significant challenge due to low-efficiency photogenerated carrier separation and transfer. Here, we present an effective approach to improve photocatalytic disinfection performance by exploiting the pyro-phototronic effect through a synergistic combination of pyroelectric properties and photocatalytic processes. A set of comprehensive studies reveals that the temperature fluctuation-induced pyroelectric field promotes photoexcited carrier separation and transfer and thus facilitates the generation of reactive oxygen species and ultimately enhances photocatalytic disinfection performance. It is worth highlighting that the constructed film demonstrated an exceptional antibacterial efficiency exceeding 95% against pathogenic bacteria under temperature fluctuations and light irradiation. Moreover, the versatile modulation role of the pyro-phototronic effect in boosting photocatalytic disinfection was corroborated. This work paves the way for improving photocatalytic disinfection efficiency by harnessing the synergistic potential of various inherent material properties.
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The risk of harmful microorganisms to ecosystems and human health has stimulated exploration of singlet oxygen (1O2)-based disinfection. It can be potentially generated via an electrocatalytic process, but is limited by the low production yield and unclear intermediate-mediated mechanism. Herein, we designed a two-site catalyst (Fe/Mo-N/C) for the selective 1O2 generation. The Mo sites enhance the generation of 1O2 precursors (H2O2), accompanied by the generation of intermediate â¢HO2/â¢O2-. The Fe site facilitates activation of H2O2 into â¢OH, which accelerates the â¢HO2/â¢O2- into 1O2. A possible mechanism for promoting 1O2 production through the ROS-mediated chain reaction is reported. The as-developed electrochemical disinfection system can kill 1 × 107 CFU mL-1 of E. coli within 8 min, leading to cell membrane damage and DNA degradation. It can be effectively applied for the disinfection of medical wastewater. This work provides a general strategy for promoting the production of 1O2 through electrocatalysis and for efficient electrochemical disinfection.
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Desinfecção , Escherichia coli , Peróxido de Hidrogênio , Oxirredução , Oxigênio Singlete , Oxigênio Singlete/química , Oxigênio Singlete/metabolismo , Desinfecção/métodos , Catálise , Escherichia coli/metabolismo , Peróxido de Hidrogênio/química , Espécies Reativas de Oxigênio/metabolismo , Espécies Reativas de Oxigênio/química , Técnicas Eletroquímicas , Molibdênio/química , Ferro/química , Águas Residuárias/química , Águas Residuárias/microbiologiaRESUMO
BACKGROUND: Environmental disinfection is essential for reducing spread of healthcare associated infections (HAIs). Previous studies report conflicting results regarding the effects of ultraviolet light (UV) in reducing infections. This trial evaluated the impact of adding pulsed xenon UV (PX-UV) to standard terminal cleaning in reducing environmentally-implicated HAIs (eiHAIs). METHODS: The LAMP trial was conducted in 2 hospitals (15 inpatient wards) utilizing a cluster randomized controlled, double-blinded, interventional crossover trial comparing standard terminal cleaning followed by either pulsed xenon ultraviolet (PX-UV) disinfection (intervention arm) or sham disinfection (control arm). The primary outcome was incidence of eiHAIs from clinical microbiology tests on the 4th day of stay or later or within 3 days after discharge from the study unit. EiHAIs included clinical cultures positive for vancomycin-resistant enterococci (VRE), extended spectrum beta-lactamase-producing Escherichia coli or Klebsiella pneumonia, methicillin-resistant Staphylococcus aureus (MRSA), and Acinetobacter baumannii, and stool PCR positive for Clostridiodes difficile. FINDINGS: Between May 18, 2017 to Jan 7, 2020, 25,732 patients were included, with an incidence of 601 eiHAI and 180,954 patient days. There was no difference in the rate of eiHAIs in the intervention and sham arms (3.49 vs 3.17 infections/1000 patient days respectively, RR 1.10 CI (0.94, 1.29, p= 0.23)). Study results were similar when stratified by eiHAI type, hospital, and unit type. CONCLUSION: The LAMP study failed to demonstrate an effect of the addition of UV light disinfection following terminal cleaning on reductions in rates of eiHAIs. Further investigations targeting hospital environmental surfaces and the role of no touch technology to reduce HAIs are needed.
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OBJECTIVES: To compare the effect of biopsy needle disinfection with 10% formalin solution alone and with povidone-iodine rectal cleaning on preventing infectious complications requiring hospitalization. METHODS: The data of 902 patients who underwent prostate biopsy by transrectal route were retrospectively analyzed. Inclusion criteria were prophylactic antibiotic use and negative urine culture before the biopsy. Three groups occurred according to the methods used during the biopsy procedure. In Group 1, 501 patients, biopsy needle disinfection was made using 10% formalin solution during the biopsy procedure. Group 2, 164 patients, applied only prophylactic antibiotics. Group 3, 237 patients, applied both 10% formalin disinfection of the biopsy needle and prebiopsy povidone-iodine rectal cleansing. Hospitalized patients because of infectious complications a month after the biopsy were our outcome measures. RESULTS: Hospitalization rates because of biopsy-related infectious complications, according to Groups 1, 2, and 3, were 2.7%, 8.5%, and 0%, respectively. The best results were observed in Group 3 and the worst in Group 2. CONCLUSIONS: The two nonantibiotic strategies, biopsy needle disinfection with formalin solution and rectal cleaning with povidone-iodine, look more effective when applied together. However, further prospective studies are required to confirm our analysis.
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Povidona-Iodo , Próstata , Masculino , Humanos , Próstata/patologia , Estudos Retrospectivos , Biópsia/efeitos adversos , Hospitalização , FormaldeídoRESUMO
A new generation of an FFP2 (Filtering Face Piece of type 2) smart face mask is achieved by integrating broadband hybrid nanomaterials and a self-assembled optical metasurface. The multifunctional FFP2 face mask shows simultaneously white light-assisted on-demand disinfection properties and versatile biosensing capabilities. These properties are achieved by a powerful combination of white light thermoplasmonic responsive hybrid nanomaterials, which provide excellent photo-thermal disinfection properties, and optical metasurface-based colorimetric biosensors, with a very low limit of pathogens detection. The realized system is studied in optical, morphological, spectroscopic, and cell viability assay experiments and environmental monitoring of harmful pathogens, thus highlighting the extraordinary properties in reusability and pathogens detection of the innovative face mask.
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Semiconductor photocatalysts, such as TiO2 and ZnO, have garnered significant attention for their ability to generate hydroxyl radicals, offering various practical applications. However, the reliance on UV light to facilitate electron-hole separation for hydroxyl radical production poses limitations. In this study, a novel approach is presented utilizing Zn@Fe core/shell particles capable of generating hydroxyl radicals without external energy input. The generation process involves electron donation from Zn to O2, resulting in the formation of radical species .O2 -/H2O2, followed by Fe-catalyzed conversion of H2O2 into hydroxyl radicals through the Fenton reaction. The release of .OH imparts good antimicrobial and antiviral properties to the Zn@Fe particles. Furthermore, the inclusion of Fe confers magnetic properties to the material. This dual functionality holds promise for diverse potential applications for the Zn@Fe particles.
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The coronavirus disease 2019 pandemic illustrates the importance of understanding the behavior and control of human pathogenic viruses in the environment. Exposure via water (drinking, bathing, and recreation) is a known route of transmission of viruses to humans, but the literature is relatively void of studies on the persistence of many viruses, especially coronaviruses, in water and their susceptibility to chlorine disinfection. To fill that knowledge gap, we evaluated the persistence and free chlorine disinfection of human coronavirus OC43 (HCoV-OC43) and its surrogates, murine hepatitis virus (MHV) and porcine transmissible gastroenteritis virus (TGEV), in drinking water and laboratory buffer using cell culture methods. The decay rate constants of human coronavirus and its surrogates in water varied, depending on virus and water matrix. In drinking water without disinfectant addition, MHV showed the largest decay rate constant (estimate ± standard error, 2.25 ± 0.09 day-1) followed by HCoV-OC43 (0.99 ± 0.12 day-1) and TGEV (0.65 ± 0.06 day-1), while in phosphate buffer without disinfectant addition, HCoV-OC43 (0.51 ± 0.10 day-1) had a larger decay rate constant than MHV (0.28 ± 0.03 day-1) and TGEV (0.24 ± 0.02 day-1). Upon free chlorine disinfection, the inactivation rates of coronaviruses were independent of free chlorine concentration and were not affected by water matrix, though they still varied between viruses. TGEV showed the highest susceptibility to free chlorine disinfection with the inactivation rate constant of 113.50 ± 7.50 mg-1 min-1 L, followed by MHV (81.33 ± 4.90 mg-1 min-1 L) and HCoV-OC43 (59.42 ± 4.41 mg-1 min-1 L). IMPORTANCE: This study addresses an important knowledge gap on enveloped virus persistence and disinfection in water. Results have immediate practical applications for shaping evidence-based water policies, particularly in the development of disinfection strategies for pathogenic virus control.
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Desinfetantes , Água Potável , Vírus da Hepatite Murina , Vírus , Animais , Camundongos , Suínos , Humanos , Desinfecção/métodos , Cloro/farmacologia , Desinfetantes/farmacologiaRESUMO
BACKGROUND: Broiler chickens are frequently colonized with Extended-Spectrum Beta-Lactamase- (ESBL-) and plasmid mediated AmpC Beta-Lactamase- (pAmpC-) producing Enterobacterales, and we are confronted with the potential spread of these resistant bacteria in the food chain, in the environment, and to humans. Research focused on identifying of transmission routes and investigating potential intervention measures against ESBL- and pAmpC- producing bacteria in the broiler production chain. However, few data are available on the effects of cleaning and disinfection (C&D) procedures in broiler stables on ESBL- and pAmpC- producing bacteria. RESULTS: We systematically investigated five broiler stables before and after C&D and identified potential ESBL- and pAmpC- colonization sites after C&D in the broiler stables, including the anteroom and the nearby surrounding environment of the broiler stables. Phenotypically resistant E. coli isolates grown on MacConkey agar with cefotaxime were further analyzed for their beta-lactam resistance genes and phylogenetic groups, as well as the relation of isolates from the investigated stables before and after C&D by whole genome sequencing. Survival of ESBL- and pAmpC- producing E. coli is highly likely at sites where C&D was not performed or where insufficient cleaning was performed prior to disinfection. For the first time, we showed highly related ESBL-/pAmpC- producing E. coli isolates detected before and after C&D in four of five broiler stables examined with cgMLST. Survival of resistant isolates in investigated broiler stables as well as transmission of resistant isolates from broiler stables to the anteroom and surrounding environment and between broiler farms was shown. In addition, enterococci (frequently utilized to detect fecal contamination and for C&D control) can be used as an indicator bacterium for the detection of ESBL-/pAmpC- E. coli after C&D. CONCLUSION: We conclude that C&D can reduce ESBL-/pAmpC- producing E. coli in conventional broiler stables, but complete ESBL- and pAmpC- elimination does not seem to be possible in practice as several factors influence the C&D outcome (e.g. broiler stable condition, ESBL-/pAmpC- status prior to C&D, C&D procedures used, and biosecurity measures on the farm). A multifactorial approach, combining various hygiene- and management measures, is needed to reduce ESBL-/pAmpC- E. coli in broiler farms.
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Proteínas de Bactérias , Galinhas , Desinfecção , Escherichia coli , Fazendas , beta-Lactamases , Animais , beta-Lactamases/genética , beta-Lactamases/metabolismo , Galinhas/microbiologia , Escherichia coli/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Desinfecção/métodos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Infecções por Escherichia coli/veterinária , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/transmissão , Doenças das Aves Domésticas/microbiologia , Doenças das Aves Domésticas/prevenção & controle , Antibacterianos/farmacologia , Filogenia , Plasmídeos/genética , Tipagem de Sequências Multilocus , Sequenciamento Completo do GenomaRESUMO
BACKGROUND AND AIMS: Periodic duodenoscope cultures are essential to timely detect contamination, but their sensitivity remains unknown. This study aims to determine the sensitivity of duodenoscope cultures and to estimate the prevalence of contaminated duodenoscope use. METHODS: We combined duodenoscope microbiological surveillance data from March 2015 to June 2022 with usage data to evaluate patient exposure to duodenoscopes contaminated with microorganisms of gut or oral origin (MGO). We identified duodenoscopes with repeated species-level contamination within a year and used molecular typing to confirm genetic relatedness. Genetically related microorganisms over multiple duodenoscope cultures of a single duodenoscope indicated a period of sustained contamination and a cluster was defined as overlapping periods of sustained contamination between different duodenoscopes. If microorganisms were not available for molecular analysis, we marked the period as unconfirmed. A sample was defined as false-negative if it did not show the target microorganism(s) in a period of sustained contamination. We used three scenarios to hypothesize about contaminated use and culture sensitivity. RESULTS: We included 556 duodenoscope cultures with 185 (33.3%) contaminated with MGO. The total usage of duodenoscopes was 5226. We identified one period of sustained contamination, six unconfirmed periods, and two clusters. Depending on our scenario assumptions, the percentage of contaminated use varied from 12.3% to 23.7%, and culture sensitivity ranged from 82.2% to 98.9%. CONCLUSIONS: Limited sensitivity of duodenoscope cultures leads to improper clearance of duodenoscopes for clinical use, increasing risks of outbreaks. The applicability of a single culture to end a duodenoscope's quarantine should be reevaluated.
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A new method for repackaging optical metamaterials formed from quartz spheres (fibers) of various diameters is proposed for ultraviolet C disinfection of infected liquids by pathogens (viruses and bacteria). The main idea of the new equipment is connected with the rotation of a contaminated fluid by screw channels within a metamaterial matrix prepared from UVC fibers/spherical optics, to improve the decontamination efficiency. In demonstration of the viability of this approach, dynamic and static inactivation of Baker's yeast via Ultraviolet C radiation regimes are used in this paper to show the efficacy of decontamination within the screw channels.
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Descontaminação , Desinfecção , Descontaminação/métodos , Desinfecção/métodos , Bactérias , Raios UltravioletaRESUMO
In this study, photostability and photodynamic antimicrobial performance of dye extracts from Hibiscus sabdariffa (HS) calyces, Sorghum bicolor (SB) leaf sheaths, Lawsonia inermis (LI) leaves and Curcuma longa (CL) roots were investigated in Acetate-HCl (AH) Buffer (pH 4.6), Tris Base-HCl (TBH) Buffer (pH 8.6), distilled water (dH2O), and Phosphate Buffer Saline (PBS, pH 7.2) using Bacillus subtilis as model for gram positive bacteria, Escherichia coli as model for gram negative bacteria, phage MS2 as model for non-envelope viruses and phage phi6 as model for envelope viruses including SARS CoV-2 which is the causative agent of COVID-19. Our results showed that the photostability of the dye extracts is in the decreasing order of LI > CL > SB > HS. The dye extract-HS is photostable in dH2O but bleaches in buffers-AH, TBH and PBS. The rate of bleaching is higher in AH compared to in TBH and PBS. The bleaching and buffers affected the photodynamic and non-photodynamic antimicrobial activity of the dye extracts. The photodynamic antibacterial activity of the dye extracts is in the decreasing order of CL > HS > LI > SB while the non-photodynamic antibacterial activity is in the decreasing order of LI > CL > HS > SB. The non-photodynamic antiviral activity pattern observed is the same as that of non-photodynamic antibacterial activity observed. However, the photodynamic antiviral activity of the dye extracts is in the decreasing order of CL > LI > HS > SB. Given their performance, the dye extracts maybe mostly suitable for environmental applications including fresh produce and food disinfection, sanitation of hands and contact surfaces where water can serve as diluent for the extracts and the microenvironment is free of salts.
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Extratos Vegetais , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Sorghum/química , Hibiscus/química , Curcuma/química , Escherichia coli/efeitos dos fármacos , Levivirus/efeitos dos fármacos , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/química , Bacillus subtilis/efeitos dos fármacos , Desinfecção , Antibacterianos/farmacologia , Antibacterianos/química , SARS-CoV-2/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Corantes/química , Corantes/farmacologia , COVID-19 , Folhas de Planta/química , Anti-Infecciosos/farmacologia , Anti-Infecciosos/química , LuzRESUMO
Ultraviolet radiation's germicidal efficacy depends on several parameters, including wavelength, radiant exposure, microbial physiology, biological matrices, and surfaces. In this work, several ultraviolet radiation sources (a low-pressure mercury lamp, a KrCl excimer, and four UV LEDs) emitting continuous or pulsed irradiation were compared. The greatest log reductions in E. coli cells and B. subtilis endospores were 4.1 ± 0.2 (18 mJ cm-2) and 4.5 ± 0.1 (42 mJ cm-2) with continuous 222 nm, respectively. The highest MS2 log reduction observed was 2.7 ± 0.1 (277 nm at 3809 mJ cm-2). Log reductions of SARS-CoV-2 with continuous 222 nm and 277 nm were ≥ 3.4 ± 0.7, with 13.3 mJ cm-2 and 60 mJ cm-2, respectively. There was no statistical difference between continuous and pulsed irradiation (0.83-16.7% [222 nm and 277 nm] or 0.83-20% [280 nm] duty rates) on E. coli inactivation. Pulsed 260 nm radiation (0.5% duty rate) at 260 nm yielded significantly greater log reduction for both bacteria than continuous 260 nm radiation. There was no statistical difference in SARS-CoV-2 inactivation between continuous and pulsed 222 nm UV-C radiation and pulsed 277 nm radiation demonstrated greater germicidal efficacy than continuous 277 nm radiation. Greater radiant exposure for all radiation sources was required to inactivate MS2 bacteriophage. Findings demonstrate that pulsed irradiation could be more useful than continuous UV radiation in human-occupied spaces, but threshold limit values should be respected. Pathogen-specific sensitivities, experimental setup, and quantification methods for determining germicidal efficacy remain important factors when optimizing ultraviolet radiation for surface decontamination or other applications.
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COVID-19 , Raios Ultravioleta , Humanos , SARS-CoV-2 , Escherichia coli/efeitos da radiação , Desinfecção/métodosRESUMO
In addition to the rising number of patients affected by viruses and bacteria, the number of fungal infections has also been rising over the years. Due to the increase in resistance to various antimycotics, investigations into further disinfection options are important. In this study, two yeasts (Candida auris and Saccharomyces cerevisiae) and a mold (Cladosporium cladosporioides) were irradiated at 365, 400, and 450 nm individually. The resulting log 1 reduction doses were determined and compared with other studies. Furthermore, fluorescence measurements of C. auris were performed to detect possible involved photosensitizers. A roughly exponential photoinactivation was observed for all three fungi and all irradiation wavelengths with higher D90 doses for longer wavelengths. The determined log 1 reduction doses of C. auris and S. cerevisiae converged with increasing wavelength. However, S. cerevisiae was more photosensitive than C. auris for all irradiation wavelengths and is therefore not a suitable C. auris surrogate for photoinactivation experiments. For the mold C. cladosporioides, much higher D90 doses were determined than for both yeasts. Concerning potential photosensitizers, flavins and various porphyrins were detected by fluorescence measurements. By excitation at 365 nm, another, so far unreported fluorophore and potential photosensitizer was also observed. Based on its fluorescence spectrum, we assume it to be thiamine.Graphic abstract.
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Candida auris , Saccharomyces cerevisiae , Humanos , Fármacos Fotossensibilizantes/farmacologia , Luz , Raios Ultravioleta , Antifúngicos , Testes de Sensibilidade MicrobianaRESUMO
Water cleaning can be provided in batch mode or in continuous flow. For the latter, some kind of framework must withhold the cleaning agents from washout. Porous structures provide an ideal ratio of surface to volume for optimal access of the water to active sites and are able to facilitate rapid and efficient fluid transport to maintain a constant flow. When functionalized with suitable photoactive agents, they could be used in solar photocatalytic disinfection. In this study, we have used the sugar cube method to fabricate PDMS-based materials that contain three different classes of photosensitizers that differ in absorption wavelength and intensity, charge as well as in ability to generate singlet oxygen. The obtained sponges are characterized by scanning electron microscopy and digital microscopy. Archimede's method was used to measure porosity and density. We show that the materials can absorb visible light and generate Reactive Oxygen Species (ROS) that are required to kill bacteria. The disinfection ability was tested by examining how irradiation time and operation mode (batch vs. flow) contribute to the performance of the material. The current strategy is highly adaptable to other (medium) pressure-driven flow systems and holds promising potential for various applications, including continuous flow photoreactions.
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BACKGROUND: The aim of this study was to analyze the cleaning and disinfection of operating rooms (ORs) status quo focusing on hygiene plans in German hospitals. METHODS: In 2016, a structured online survey was sent to infection prevention and control (IPC) specialists at the cost calculation hospitals of the Institute for the Hospital Remuneration System (InEK) and all university hospitals in Germany (n = 365). RESULTS: With a response rate of 27.4%, 78% stated that written hygiene plans were available. After cleaning and disinfecting an OR with a "septic" patient, 55% waited until surfaces were dry before reusing in accordance with national recommendations, 27% waited > 30 min. Additionally, 28% of hospitals had ORs only for "septic" patients. In 56% "septic" patients were only operated on at the end of the program. Postoperative monitoring of patients with bacteria with special IPC requirements took place in the post anesthesia care unit (PACU) (29%), operating room (OR) (52%), intensive care unit (ICU) (53%), and in the intermediate care unit (IMC) (19%). DISCUSSION AND CONCLUSIONS: Despite written hygiene plans in place the partly long duration of OR nonuse time following IPC measures, the consistent continued use of stratification for "septic" patients and the postoperative follow-up care of patients with colonizing/infecting bacteria with special IPC requirements in the OR and high care areas represent relevant potential for improvement.
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Infecção Hospitalar , Desinfecção , Controle de Infecções , Salas Cirúrgicas , Alemanha , Humanos , Salas Cirúrgicas/normas , Salas Cirúrgicas/estatística & dados numéricos , Controle de Infecções/métodos , Desinfecção/métodos , Desinfecção/normas , Infecção Hospitalar/prevenção & controle , Hospitais/estatística & dados numéricos , Inquéritos e QuestionáriosRESUMO
Ultraviolet germicidal irradiation (UVGI) and ozone disinfection are crucial methods for mitigating the airborne transmission of pathogenic microorganisms in high-risk settings, particularly with the emergence of respiratory viral pathogens such as SARS-CoV-2 and avian influenza viruses. This study quantitatively investigates the influence of UVGI and ozone on the viability ofE. coliin bioaerosols, with a particular focus on howE. coliviability depends on the size of the bioaerosols, a critical factor that determines deposition patterns within the human respiratory system and the evolution of bioaerosols in indoor environments. This study used a controlled small-scale laboratory chamber whereE. colisuspensions were aerosolized and subjected to varying levels of UVGI and ozone levels throughout the exposure time (2-6 s). The normalized viability ofE. coliwas found to be significantly reduced by UVGI (60-240µW s cm-2) as the exposure time increased from 2 to 6 s, and the most substantial reduction ofE. colinormalized viability was observed when UVGI and ozone (65-131 ppb) were used in combination. We also found that UVGI reduced the normalized viability ofE. coliin bioaerosols more significantly with smaller sizes (0.25-0.5µm) than with larger sizes (0.5-2.5µm). However, when combining UVGI and ozone, the normalized viability was higher for smaller particle sizes than for the larger ones. The findings provide insights into the development of effective UVGI disinfection engineering methods to control the spread of pathogenic microorganisms in high-risk environments. By understanding the influence of the viability of microorganisms in various bioaerosol sizes, we can optimize UVGI and ozone techniques to reduce the potential risk of airborne transmission of pathogens.
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Desinfecção , Ozônio , Animais , Humanos , Desinfecção/métodos , Ozônio/farmacologia , Microbiologia do Ar , Raios UltravioletaRESUMO
Widely used antioxidants can enter the environment via urban stormwater systems and form disinfection byproducts (DBPs) during chlorination in downstream drinking water processes. Herein, we comprehensively investigated the occurrence of 39 antioxidants from stormwater runoff to surface water. After a storm event, the concentrations of the antioxidants in surface water increased by 1.4-fold from 102-110 ng/L to 128-139 ng/L. Widespread antioxidants during the stormwater event could transform into toxic DBPs during disinfection. Moreover, the yields of trihalomethanes, haloacetaldehydes, haloacetonitriles (HANs), and halonitromethanes during the chlorination of widely used antioxidants considerably increased with an increasing chlorine dose and contact time. Specifically, the yields of dichloroacetonitrile during the chlorination of diphenylamine (DPA) and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) were higher than those of most reported amino acid precursors, indicating that DPA and 6PPD might be important precursors of HANs. Exploring the intermediates using GC × GC-time-of-flight high-resolution mass spectrometry helped reveal potential pathways from DPA to HANs, whose formation could be attributed to the intermediate carbazole and indole moieties detected in this study. This study provides insights into the transport and transformation of commonly used antioxidants in a water environment and during water treatment processes, highlighting the potential risks of anthropogenic pollutants from a DBP perspective.
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Antioxidantes , Desinfecção , Poluentes Químicos da Água/química , Purificação da Água , HalogenaçãoRESUMO
Despite the critical importance of virus disinfection by chlorine, our fundamental understanding of the relative susceptibility of different viruses to chlorine and robust quantitative relationships between virus disinfection rate constants and environmental parameters remains limited. We conducted a systematic review of virus inactivation by free chlorine and used the resulting data set to develop a linear mixed model that estimates chlorine inactivation rate constants for viruses based on experimental conditions. 570 data points were collected in our systematic review, representing 82 viruses over a broad range of environmental conditions. The harmonized inactivation rate constants under reference conditions (pH = 7.53, T = 20 °C, [Cl-] < 50 mM) spanned 5 orders of magnitude, ranging from 0.0196 to 1150 L mg-1 min-1, and uncovered important trends between viruses. Whereas common surrogate bacteriophage MS2 does not serve as a conservative chlorine disinfection surrogate for many human viruses, CVB5 was one of the most resistant viruses in the data set. The model quantifies the role of pH, temperature, and chloride levels across viruses, and an online tool allows users to estimate rate constants for viruses and conditions of interest. Results from the model identified potential shortcomings in current U.S. EPA drinking water disinfection requirements.
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Cloro , Desinfecção , Cloro/farmacologia , Inativação de Vírus/efeitos dos fármacos , Vírus/efeitos dos fármacos , Desinfetantes/farmacologiaRESUMO
The sensitivity of enteroviruses to disinfectants varies among genetically similar variants and coincides with amino acid changes in capsid proteins, although the effect of individual substitutions remains unknown. Here, we employed reverse genetics to investigate how amino acid substitutions in coxsackievirus B5 (CVB5) capsid proteins affect the virus' sensitivity to free chlorine and heat treatment. Of ten amino acid changes observed in CVB5 variants with free chlorine resistance, none significantly reduced the chlorine sensitivity, indicating a minor role of the capsid composition in chlorine sensitivity of CVB5. Conversely, a subset of these amino acid changes located at the C-terminal region of viral protein 1 led to reduced heat sensitivity. Cryo-electron microscopy revealed that these changes affect the assembly of intermediate viral states (altered and empty particles), suggesting that the mechanism for reduced heat sensitivity could be related to improved molecular packing of CVB5, resulting in greater stability or altered dynamics of virus uncoating during infection.
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Proteínas do Capsídeo , Cloro , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/química , Cloro/farmacologia , Microscopia Crioeletrônica , Substituição de Aminoácidos , Enterovirus Humano B/genética , AminoácidosRESUMO
Increasing radical yields to reduce UV fluence requirement for achieving targeted removal of micropollutants in water would make UV-based advanced oxidation processes (AOPs) less energy demanding in the context of United Nations' Sustainable Development Goals and carbon neutrality. We herein demonstrate that, by switching the UV radiation source from conventional low-pressure UV at 254 nm (UV254) to emerging Far-UVC at 222 nm (UV222), the fluence-based concentration of HO⢠in the UV/peroxydisulfate (UV/PDS) AOP increases by 6.40, 2.89, and 6.00 times in deionized water, tap water, and surface water, respectively, with increases in the fluence-based concentration of SO4â¢- also by 5.06, 5.81, and 55.47 times, respectively. The enhancement to radical generation is confirmed using a kinetic model. The pseudo-first-order degradation rate constants of 16 micropollutants by the UV222/PDS AOP in surface water are predicted to be 1.94-13.71 times higher than those by the UV254/PDS AOP. Among the tested water matrix components, chloride and nitrate decrease SO4â¢- but increase HO⢠concentration in the UV222/PDS AOP. Compared to the UV254/PDS AOP, the UV222/PDS AOP decreases the formation potentials of carbonaceous disinfection byproducts (DBPs) but increases the formation potentials of nitrogenous DBPs.