Evaluation of acute corneal damage induced by 222-nm and 254-nm ultraviolet light in Sprague–Dawley rats

Kaidzu, Sachiko; Sugihara, Kazunobu; Sasaki, Masahiro; Nishiaki, Aiko; Igarashi, Tatsushi; Tanito, Masaki

doi:10.1080/10715762.2019.1603378

Cited by 79 publications

(67 citation statements)

References 21 publications

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“…Given the concerns about UV 254 noted above, there is increasing interest in using 222-nm UV radiation (UV 222 ) for decontamination (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). Importantly, while UV 222 is absorbed well by nucleic acids, it is also well absorbed by proteins, which are much more abundant in cells than nucleic acids, and kills bacteria and spores, reportedly more rapidly than UV 254 (12,13).…”

mentioning

confidence: 99%

DNA Damage Kills Bacterial Spores and Cells Exposed to 222-Nanometer UV Radiation

Taylor

Camilleri

Craft

et al. 2020

Appl Environ Microbiol

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This study examined the microbicidal activity of 222-nm UV radiation (UV222), which is potentially a safer alternative to the 254-nm UV radiation (UV254) that is often used for surface decontamination. Spores and/or growing and stationary-phase cells of Bacillus cereus, Bacillus subtilis, Bacillus thuringiensis, Staphylococcus aureus, and Clostridioides difficile and a herpesvirus were all killed or inactivated by UV222 and at lower fluences than with UV254. B. subtilis spores and cells lacking the major DNA repair protein RecA were more sensitive to UV222, as were spores lacking their DNA-protective proteins, the α/β-type small, acid-soluble spore proteins. The spore cores’ large amount of Ca2+-dipicolinic acid (∼25% of the core dry weight) also protected B. subtilis and C. difficile spores against UV222, while spores’ proteinaceous coat may have given some slight protection against UV222. Survivors among B. subtilis spores treated with UV222 acquired a large number of mutations, and this radiation generated known mutagenic photoproducts in spore and cell DNA, primarily cyclobutane-type pyrimidine dimers in growing cells and an α-thyminyl-thymine adduct termed the spore photoproduct (SP) in spores. Notably, the loss of a key SP repair protein markedly decreased spore UV222 resistance. UV222-treated B. subtilis spores germinated relatively normally, and the generation of colonies from these germinated spores was not salt sensitive. The latter two findings suggest that UV222 does not kill spores by general protein damage, and thus, the new results are consistent with the notion that DNA damage is responsible for the killing of spores and cells by UV222. IMPORTANCE Spores of a variety of bacteria are resistant to common decontamination agents, and many of them are major causes of food spoilage and some serious human diseases, including anthrax caused by spores of Bacillus anthracis. Consequently, there is an ongoing need for efficient methods for spore eradication, in particular methods that have minimal deleterious effects on people or the environment. UV radiation at 254 nm (UV254) is sporicidal and commonly used for surface decontamination but can cause deleterious effects in humans. Recent work, however, suggests that 222-nm UV (UV222) may be less harmful to people than UV254 yet may still kill bacteria and at lower fluences than UV254. The present work has identified the damage by UV222 that leads to the killing of growing cells and spores of some bacteria, many of which are human pathogens, and UV222 also inactivates a herpesvirus.

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confidence: 99%

DNA Damage Kills Bacterial Spores and Cells Exposed to 222-Nanometer UV Radiation

Taylor

Camilleri

Craft

et al. 2020

Appl Environ Microbiol

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“…In contrast, recent studies have shown that 222-nm UVC light, which is part of the far-UVC light (207-222 nm) spectrum, shares similar germicidal properties, but is less harmful to the skin and eyes than 254-nm UVC light. [6][7][8][9][10][11][12] The studies together suggested that a 222-nm UVC disinfection device may be easier to use for routine device cleaning than a 254-nm UVC disinfection device in environments where patients and medical staff exist, such as nurse stations and patient rooms. However, further studies investigating the safety of 222-nm UVC disinfection in occupied spaces would be required in future.…”

Section: Discussionmentioning

confidence: 99%

“…Previous reports had shown that 222-nm UVC light, which is part of the far-UVC light (207-222 nm) spectrum, also has highly effective germicidal properties, and is less harmful to the skin and eyes than 254-nm UVC. [6][7][8][9][10][11] However, only few reports exist regarding the efficacy of 222-nm UVC disinfection in clinical settings. 12 In this study, we investigated the extent of MRSA contamination in hospital-use-only mobile phones used by doctors, and the efficacy of 222-nm UVC disinfection on these devices.…”

mentioning

confidence: 99%

Methicillin-resistant Staphylococcus aureus contamination of hospital-use-only mobile phones and efficacy of 222-nm ultraviolet disinfection

Kaiki

Kitagawa

Hara

et al. 2021

American Journal of Infection Control

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Background: Mobile phones may be contaminated with nosocomial pathogens such as methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study was to investigate the MRSA contamination rate on doctors' hospital-use-only mobile phones and the efficacy of 222-nm ultraviolet light (UV) disinfection. Methods: We investigated the MRSA contamination rate of doctors' hospital-use-only mobile phones, as well as the reduction in MRSA counts on plastic plates and aerobic bacteria (AB) on mobile phones before and after exposure to 222-nm UV irradiation. Results: Five (10%) of the 50 mobile phones investigated were contaminated with MRSA. Exposure to 0.1 mJ/ cm 2 222-nm UVC irradiation for 1.5 and 2.5 min (9 and 15 mJ/cm 2) achieved mean log 10 MRSA colony-forming units reductions of 2.91 and 3.95, respectively. Exposure to 9 mJ/cm 2 222-nm UVC irradiation (0.1 mW/ cm 2 for 1.5 minutes) significantly reduced AB contamination on mobile phones (P < .001). Conclusions: The use of 222-nm UV disinfection resulted in effective in vitro reduction of MRSA and significantly reduced AB contamination of mobile phone surfaces.

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“…However, exposure to these lamps has been associated with health risks, which mainly involve damage to the eyes and skin [ 81 , 82 ]. Nevertheless, recent evidences suggested that UV-C at 222 nm exhibited germicidal activity [ 83 , 84 , 85 ], but inflicted no damage on the eyes and skin of mice [ 86 , 87 , 88 ]. These data are still preliminary and further research is needed to ascertain the safety of UV light at 222 nm, especially its potential long-term effects on human health.…”

Section: Viral Properties Of Ultraviolet Lightmentioning

confidence: 99%

Control Measures for SARS-CoV-2: A Review on Light-Based Inactivation of Single-Stranded RNA Viruses

et al. 2020

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SARS-CoV-2 is a single-stranded RNA virus classified in the family Coronaviridae. In this review, we summarize the literature on light-based (UV, blue, and red lights) sanitization methods for the inactivation of ssRNA viruses in different matrixes (air, liquid, and solid). The rate of inactivation of ssRNA viruses in liquid was higher than in air, whereas inactivation on solid surfaces varied with the type of surface. The efficacy of light-based inactivation was reduced by the presence of absorptive materials. Several technologies can be used to deliver light, including mercury lamp (conventional UV), excimer lamp (UV), pulsed-light, and light-emitting diode (LED). Pulsed-light technologies could inactivate viruses more quickly than conventional UV-C lamps. Large-scale use of germicidal LED is dependent on future improvements in their energy efficiency. Blue light possesses virucidal potential in the presence of exogenous photosensitizers, although femtosecond laser (ultrashort pulses) can be used to circumvent the need for photosensitizers. Red light can be combined with methylene blue for application in medical settings, especially for sanitization of blood products. Future modelling studies are required to establish clearer parameters for assessing susceptibility of viruses to light-based inactivation. There is considerable scope for improvement in the current germicidal light-based technologies and practices.

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Evaluation of acute corneal damage induced by 222-nm and 254-nm ultraviolet light in Sprague–Dawley rats

Cited by 79 publications

References 21 publications

DNA Damage Kills Bacterial Spores and Cells Exposed to 222-Nanometer UV Radiation

DNA Damage Kills Bacterial Spores and Cells Exposed to 222-Nanometer UV Radiation

Methicillin-resistant Staphylococcus aureus contamination of hospital-use-only mobile phones and efficacy of 222-nm ultraviolet disinfection

Control Measures for SARS-CoV-2: A Review on Light-Based Inactivation of Single-Stranded RNA Viruses

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