Ameliorative and Disinfection Effects of Ultraviolet-C Radiation on Experimentally Induced and Infected Skin Wounds: A Mice Model Study

Only ultraviolet-C (UV-C) from UV lights, which are emitted by the sun and absorbed by the atmosphere's ozone layer, does not reach the Earth's surface. UV-C is a powerful disinfection method that is commonly used to sterilize fluids, air, and surfaces. There is a little knowledge of the effects of UV-C radiation on living bodies. The purpose of this study is to examine the ameliorative effect of UV-C on skin lesions in mice that have been experimentally created and infected with Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus sp. In total, 32 mice were used, and 4 mm skin defects were created and lesions infected with bacteria. Half of the mice in each group were treated with 254 nm UV-C twice a day for 4 days before being euthanatized. Blood samples were collected for hematological analysis, while skin samples were collected for microbiological, pathological, and immunohistochemical examinations. In addition, pathological examinations were performed on visceral organ samples. UV-C treatment caused rapid healing and complete or significant disinfection of skin lesions. Moreover, UV-C treatment reduced caspase-3 expressions in lesioned areas, according to immunochemistry. There were no pathological findings in visceral organs as a result of UV-C treatment. This study found that UV-C can be used to treat and disinfect infected skin lesions in short period and repeated doses.

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Photochemical treatment of organic constituents and bacterial pathogens from synthetic slaughterhouse wastewater by combining vacuum-UV and UV-C

10.32920/ryerson.14643972.v1 ◽

2021 ◽

Author(s):

Mauricio Barrera

Keyword(s):

Vacuum Ultraviolet ◽

Irradiation Time ◽

Removal Rates ◽

Slaughterhouse Wastewater ◽

Toc Removal ◽

Short Period ◽

Bacteria Inactivation ◽

Ultraviolet C ◽

Inactivation Efficiency ◽

Uv C

The reduction and degradation of total organic carbon (TOC) and bacteria inactivation efficiency using Vacuum-Ultraviolet (VUV) oxidation process Ultraviolet-C (UV-C) photolytic process, and their combination (UV-C/VUV and VUV/UV-C) from synthetic slaughterhouse wastewater was investigated. TOC removal rates achieved during continuous mode operation were 6.2%, 5.5%, 5.8%, and 6.1%, respectively. In a second stage, H₂O₂ was added to both processes, UV-C/H₂O₂ and VUV/H₂O₂, and it was found that TOC removal rates were increased twice as much during continious flow operation to 10.8% and 12.2%, respectively. The optimum molar ration of H₂O₂/TOC was found to be 2.5 and 1.5 for each process respectively. Finally, it was observed that all photochemical processes achieved over 99.999% (five logs) of bacteria inactivation in a short period of irradiation time, 27.6 sec.

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Photochemical treatment of organic constituents and bacterial pathogens from synthetic slaughterhouse wastewater by combining vacuum-UV and UV-C

10.32920/ryerson.14643972 ◽

2021 ◽

Author(s):

Mauricio Barrera

Keyword(s):

Vacuum Ultraviolet ◽

Irradiation Time ◽

Removal Rates ◽

Slaughterhouse Wastewater ◽

Toc Removal ◽

Short Period ◽

Bacteria Inactivation ◽

Ultraviolet C ◽

Inactivation Efficiency ◽

Uv C

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Effectiveness of Ultraviolet-C Room Disinfection on Preventing Healthcare-Associated Clostridioides difficile Infection

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.512 ◽

2020 ◽

Vol 41 (S1) ◽

pp. s33-s33

Author(s):

Michihiko Goto ◽

Erin Balkenende ◽

Gosia Clore ◽

Rajeshwari Nair ◽

Loretta Simbartl ◽

...

Keyword(s):

Acute Care ◽

Acute Care Hospitals ◽

Incidence Rates ◽

Positive Test ◽

Negative Binomial Regression Model ◽

Test Results ◽

Clostridioides Difficile ◽

Ultraviolet C ◽

Healthcare Associated ◽

Uv C

Background: Enhanced terminal room cleaning with ultraviolet C (UVC) disinfection has become more commonly used as a strategy to reduce the transmission of important nosocomial pathogens, including Clostridioides difficile, but the real-world effectiveness remains unclear. Objectives: We aimed to assess the association of UVC disinfection during terminal cleaning with the incidence of healthcare-associated C. difficile infection and positive test results for C. difficile within the nationwide Veterans Health Administration (VHA) System. Methods: Using a nationwide survey of VHA system acute-care hospitals, information on UV-C system utilization and date of implementation was obtained. Hospital-level incidence rates of clinically confirmed hospital-onset C. difficile infection (HO-CDI) and positive test results with recent healthcare exposures (both hospital-onset [HO-LabID] and community-onset healthcare-associated [CO-HA-LabID]) at acute-care units between January 2010 and December 2018 were obtained through routine surveillance with bed days of care (BDOC) as the denominator. We analyzed the association of UVC disinfection with incidence rates of HO-CDI, HO-Lab-ID, and CO-HA-LabID using a nonrandomized, stepped-wedge design, using negative binomial regression model with hospital-specific random intercept, the presence or absence of UVC disinfection use for each month, with baseline trend and seasonality as explanatory variables. Results: Among 143 VHA acute-care hospitals, 129 hospitals (90.2%) responded to the survey and were included in the analysis. UVC use was reported from 42 hospitals with various implementation start dates (range, June 2010 through June 2017). We identified 23,021 positive C. difficile test results (HO-Lab ID: 5,014) with 16,213 HO-CDI and 24,083,252 BDOC from the 129 hospitals during the study period. There were declining baseline trends nationwide (mean, −0.6% per month) for HO-CDI. The use of UV-C had no statistically significant association with incidence rates of HO-CDI (incidence rate ratio [IRR], 1.032; 95% CI, 0.963–1.106; P = .65) or incidence rates of healthcare-associated positive C. difficile test results (HO-Lab). Conclusions: In this large quasi-experimental analysis within the VHA System, the enhanced terminal room cleaning with UVC disinfection was not associated with the change in incidence rates of clinically confirmed hospital-onset CDI or positive test results with recent healthcare exposure. Further research is needed to understand reasons for lack of effectiveness, such as understanding barriers to utilization.Funding: NoneDisclosures: None

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Ultraviolet-C as a Viable Reprocessing Method for Disposable Masks and Filtering Facepiece Respirators

Polymers ◽

10.3390/polym13050801 ◽

2021 ◽

Vol 13 (5) ◽

pp. 801

Author(s):

Talita Nicolau ◽

Núbio Gomes Filho ◽

Andrea Zille

Keyword(s):

Literature Review ◽

Systematic Literature Review ◽

Personal Protective Equipment ◽

State Of The Art ◽

Protective Equipment ◽

Multiple Methods ◽

Ultraviolet C ◽

Single Use ◽

Uv C ◽

New Strategies

In normal conditions, discarding single-use personal protective equipment after use is the rule for its users due to the possibility of being infected, particularly for masks and filtering facepiece respirators. When the demand for these protective tools is not satisfied by the companies supplying them, a scenario of shortages occurs, and new strategies must arise. One possible approach regards the disinfection of these pieces of equipment, but there are multiple methods. Analyzing these methods, Ultraviolet-C (UV-C) becomes an exciting option, given its germicidal capability. This paper aims to describe the state-of-the-art for UV-C sterilization in masks and filtering facepiece respirators. To achieve this goal, we adopted a systematic literature review in multiple databases added to a snowball method to make our sample as robust as possible and encompass a more significant number of studies. We found that UV-C’s germicidal capability is just as good as other sterilization methods. Combining this characteristic with other advantages makes UV-C sterilization desirable compared to other methods, despite its possible disadvantages.

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Inactivation of Candida auris and Candida albicans by Ultraviolet-C

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.868 ◽

2020 ◽

Vol 41 (S1) ◽

pp. s292-s292

Author(s):

William Rutala ◽

Hajime Kanamori ◽

Maria Gergen ◽

Emily Sickbert-Bennett ◽

David Jay Weber

Keyword(s):

Infection Prevention ◽

Antifungal Drugs ◽

Candida Auris ◽

Healthcare Facilities ◽

Environmental Surfaces ◽

Route Of Transmission ◽

Indirect Exposure ◽

Ultraviolet C ◽

Severe Infections ◽

Uv C

Background:Candida auris is an emerging fungal pathogen that is often resistant to major classes of antifungal drugs. It is considered a serious global health threat because it has caused severe infections with frequent mortality in over a dozen countries. C. auris can survive on healthcare environmental surfaces for at least 7 days, and it causes outbreaks in healthcare facilities. C. auris has an environmental route of transmission. Thus, infection prevention strategies, such as surface disinfection and room decontamination technologies (eg, ultraviolet [UV-C] light), will be essential to controlling transmission. Unfortunately, data are limited regarding the activity of UV-C to inactivate this pathogen. In this study, a UV-C device was evaluated for its antimicrobial activity against C. auris and C. albicans. Methods: We tested the antifungal activity of a single UV-C device using the vegetative bacteria cycle, which delivers a reflected dose of 12,000 µW/cm2. This testing was performed using Formica sheets (7.6 × 7.6 cm; 3 × 3 inches). The carriers were inoculated with C. auris or C. albicans and placed horizontal on the surface or vertical (ie, perpendicular) to the vertical UV-C lamp and at a distance from 1. 2 m (~4 ft) to 2.4 m (~8 ft). Results: Direct UV-C, with or without FCS (log10 reduction 4.57 and 4.45, respectively), exhibited a higher log10 reduction than indirect UV-C for C. auris (log10 reduction 2.41 and 1.96, respectively), which was statistically significant (Fig. 1 and Table 1). For C. albicans, although direct UV-C had a higher log10 reduction (log10 reduction with and without FCS, 5.26 and 5.07, respectively) compared to indirect exposure (log10 reduction with and without FCS, 3.96 and 3.56, respectively), this difference was not statistically significant. The vertical UV had statistically higher log10 reductions than horizontal UV against C. auris and C. albicans with FCS and without FCS. For example, for C. auris with FCS the log10 reduction for vertical surfaces was 4.92 (95% CI 3.79, 6.04) and for horizontal surfaces the log10 reduction was 2.87 (95% CI, 2.36–3.38). Conclusions:C. auris can be inactivated on environmental surfaces by UV-C as long as factors that affect inactivation are optimized (eg, exposure time). These data and other published UV-C data should be used in developing cycle parameters that prevent contaminated surfaces from being a source of acquisition by staff or patients of this globally emerging pathogen.Funding: NoneDisclosures: None

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Minimal, superficial DNA damage in human skin from filtered far‐ultraviolet‐C (UV‐C)

British Journal of Dermatology ◽

10.1111/bjd.19816 ◽

2021 ◽

Cited By ~ 1

Author(s):

R.P. Hickerson ◽

M.J. Conneely ◽

S.K. Hirata Tsutsumi ◽

K. Wood ◽

D.N. Jackson ◽

...

Keyword(s):

Dna Damage ◽

Human Skin ◽

Ultraviolet C ◽

Far Ultraviolet ◽

Uv C

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The Occurrence and Comparative Phenotypic Characteristics of Staphylococcus spp. from Healthy and Diseased, Household and Shelter Dogs, Based on Routine Biochemical Diagnostic Methods

Polish Journal of Microbiology ◽

10.33073/pjm-2011-003 ◽

2011 ◽

Vol 60 (1) ◽

pp. 19-26 ◽

Cited By ~ 4

Author(s):

ANDRZEJ KASPROWICZ ◽

ANNA BIAŁECKA ◽

JOANNA BIAŁECKA ◽

IZABELA GODZISZ ◽

WIESŁAW BARABASZ ◽

...

Keyword(s):

Skin Lesions ◽

Common Species ◽

Carrier State ◽

Diagnostic Methods ◽

Animal Shelter ◽

Staphylococcal Species ◽

Staphylococcus Intermedius ◽

Shelter Dogs ◽

Staphylococcus Spp ◽

Infected Skin

To determine the staphylococcal colonization pattern in healthy and diseased dogs, living in two particular environments, a number of microbiological samples were taken. Overall, twenty dogs, either healthy or with infected skin lesions, were examined. In each case bacterial swabs were collected from the nasal mucosa, ear, perineum, lumbo-sacralis triangle, and from the infection sites if such were present. A total number of 104 isolates representing different staphylococcal species were isolated and identified using routine biochemical methods applied in diagnostic laboratories. Among 17 isolated staphylococcal species, Staphylococcus intermedius was the most common species isolated from both healthy or diseased dogs living either in animal shelter or household environments. The pattern of Staphylococcus sp. colonization differs considerably for animals living in the two tested habitats. In particular, S. aureus MRSA and MSSA isolates were detected only in infected skin lesion samples from animals that dwelled in the animal shelter. As could be expected, S. intermedius was found to be a predominant causative agent in canine skin infections. In our study, we demonstrated that S. intermedius in its carrier-state, inhabits mainly the mucosal membrane of the nasal vestibule. It was also found in the samples taken from the skin, the lumbo-sacralis triangle and perineum, but was rarely isolated from the ears.

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Mapping of UV-C dose and SARS-CoV-2 viral inactivation across N95 respirators during decontamination

Scientific Reports ◽

10.1038/s41598-021-98121-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alisha Geldert ◽

Alison Su ◽

Allison W. Roberts ◽

Guillaume Golovkine ◽

Samantha M. Grist ◽

...

Keyword(s):

Optical Simulation ◽

Pathogen Inactivation ◽

Viral Inactivation ◽

Flexible Form ◽

Measurement Tools ◽

Ultraviolet C ◽

N95 Respirators ◽

Uv C ◽

Dose Difference

AbstractDuring public health crises like the COVID-19 pandemic, ultraviolet-C (UV-C) decontamination of N95 respirators for emergency reuse has been implemented to mitigate shortages. Pathogen photoinactivation efficacy depends critically on UV-C dose, which is distance- and angle-dependent and thus varies substantially across N95 surfaces within a decontamination system. Due to nonuniform and system-dependent UV-C dose distributions, characterizing UV-C dose and resulting pathogen inactivation with sufficient spatial resolution on-N95 is key to designing and validating UV-C decontamination protocols. However, robust quantification of UV-C dose across N95 facepieces presents challenges, as few UV-C measurement tools have sufficient (1) small, flexible form factor, and (2) angular response. To address this gap, we combine optical modeling and quantitative photochromic indicator (PCI) dosimetry with viral inactivation assays to generate high-resolution maps of “on-N95” UV-C dose and concomitant SARS-CoV-2 viral inactivation across N95 facepieces within a commercial decontamination chamber. Using modeling to rapidly identify on-N95 locations of interest, in-situ measurements report a 17.4 ± 5.0-fold dose difference across N95 facepieces in the chamber, yielding 2.9 ± 0.2-log variation in SARS-CoV-2 inactivation. UV-C dose at several on-N95 locations was lower than the lowest-dose locations on the chamber floor, highlighting the importance of on-N95 dose validation. Overall, we integrate optical simulation with in-situ PCI dosimetry to relate UV-C dose and viral inactivation at specific on-N95 locations, establishing a versatile approach to characterize UV-C photoinactivation of pathogens contaminating complex substrates such as N95s.

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