Portable pulsed xenon ultraviolet light disinfection in a teaching hospital animal laboratory in China

Pulsed ultraviolet (PUV) disinfection of artificially contaminated seawater seeded with high levels of pathogen disease indicators as an alternative for the shellfish industry depuration systems

The increase in pathogen levels in seawater threatens the safety of entire aquatic ecosystems. Foodborne pathogens can potentially accumulate in shellfish, especially in filter feeders such as bivalves, requiring an efficient depuration process before consumption. Alternative approaches to promote a cost-efficient purge at depuration plants are urgently needed. A small prototype pulsed ultraviolet (PUV) light recirculation system was designed, and its depuration potential was tested in a seawater matrix artificially contaminated with high levels of microbial pathogens Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Bacillus cereus and Candida albicans. The analysis of treatment parameters including voltage, number of pulses and duration of treatment was performed to ensure the highest reduction in contaminant levels. Optimal PUV disinfection was attained at 60 pulses/min at 1 kV for 10 min (a UV output of 12.9 J/cm²). All reductions were statistically significant, and the greatest was observed for S. aureus (5.63 log₁₀), followed by C. albicans (5.15 log₁₀), S. typhimurium (5 log₁₀), B. cereus (4.59 log₁₀) and E. coli (4.55 log₁₀). PUV treatment disrupted the pathogen DNA with the result that S. aureus, C. albicans and S. typhimurium were not detectable by PCR. Regulations were reviewed to address the applicability of PUV treatment as a promising alternative to assist in the reduction of microbial pathogens at depuration plants due to its high efficiency, short treatment period, high UV dose and recirculation system as currently employed in shellfish depuration plants.

Hospital surface disinfection using ultraviolet germicidal irradiation technology: A review

Ultraviolet germicidal irradiation (UVGI) technologies have emerged as a promising alternative to biocides as a means of surface disinfection in hospitals and other healthcare settings. This paper reviews the methods used by researchers and clinicians in deploying and evaluating the efficacy of UVGI technology. The type of UVGI technology used, the clinical setting where the device was deployed, and the methods of environmental testing that the researchers followed are investigated. The findings suggest that clinical UVGI deployments have been growing steadily since 2010 and have increased dramatically since the start of the COVID-19 pandemic. Hardware platforms and operating procedures vary considerably between studies. Most studies measure efficacy of the technology based on the objective measurement of bacterial bioburden reduction; however, studies conducted over longer durations have examined the impact of UVGI on the reduction of healthcare associated infections (HCAIs). Future trends include increased automation and the use of UVGI technologies that are safer for use around people. Although existing evidence seems to support the efficacy of UVGI as a tool capable of reducing HCAIs, more research is needed to measure the magnitude of these effects and to establish recommended best practices.

A Practical Assessment of the Disinfectant Efficacy of UV Light with and without Ozone Using a Novel Transfer Hatch in a Research Animal Facility

Most in vivo animal research and breeding using mice and rats in China takes place in facilities under barrier conditions. Items being moved across the barrier are typically disinfected using UV radiation in a transfer hatch. However, the time periods necessary for this disinfection technique are inefficient, and disinfection is frequently incomplete, especially if concealed surfaces are present. The current study used a newly developed transfer hatch incorporating both UV and ozone disinfection to examine disinfection efficacy against 4 bacteria species (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii). Disinfection trials used UV and ozone, applied separately and in combination, for up to 30 min. Separate and combined treatments were also tested with a UV barrier. We found that if UV radiation has direct contact with surfaces, it is an efficient disinfection method. However, where surfaces are concealed by a UV barrier, UV radiation performs relatively poorly. The results of this study indicate that a combination of UV and ozone produces the most effective disinfection and is markedly quicker than current disinfection times for UV applied on its own. This novel transfer hatch design therefore allows more complete and efficient disinfection, improves workflow, and reduces barrier breaches by pathogens that may affect animal health and welfare and compromise research outcomes.

Comparison of the Antimicrobial Effect of Zataria Multiflora Essence and Deconex Surface on Microbial Load of Emergency Ambulances

This study aimed to compare the antimicrobial effect of Deconex Surface, a common disinfectant, and Zataria multiflora essence on microbial load of Emergency ambulance equipment in Iran. The samples were selected from all the ambulances through convenience sampling. Before the intervention, the cultures were obtained from the contact surfaces and the surfaces were then disinfected with Deconex and Zataria multiflora. Then, repeated cultures were obtained from the same surfaces. Next, the samples were immediately sent to a microbiology lab. The obtained data were entered into SPSS 2016 and analyzed using statistical tests. Results showed that disinfecting effect of Zataria multiflora is better than Deconex in eliminating certain bacterial species such as Staphylococcus and Bacillus. So Zataria multiflora essence can be used as a surface and hospital equipment disinfectant along with other disinfectant compounds.

Ultraviolet C as a method of disinfecting medical silicone used in facial prostheses: An in vitro study

STATEMENT OF PROBLEM

Hygiene and disinfection are important factors for preserving facial prostheses and supporting tissue health. However, a method that does not accelerate degradation or color change is necessary.

PURPOSE

The purpose of this in vitro study was to evaluate the effectiveness of irradiation with ultraviolet C light-emitting diode (UV-C LED) light in the disinfection and initial color stability of the silicone (A-588-1; Factor II) used in facial prostheses.

MATERIAL AND METHODS

One hundred and twenty specimens were made, contaminated by multispecies biofilm, and divided into 5 groups (n = 24) with different treatments: control, distilled water, 0.12% chlorhexidine, UV-C LED light, and dimethyl sulfoxide (DMSO) as the negative control. Cell viability was measured by the methyl tetrazolium salt method. Statistical analysis was performed by generalized linear models. Additional descriptive analysis was performed for color analysis by using 16 silicone specimens made with light and dark intrinsic coloring in 4 groups (controls and treatments n=4) submitted to UV-C LED light. The ΔE of the specimens was obtained by CIEDE200.

RESULTS

The results of cell viability demonstrated a statistically significant difference among the groups (P<.001), with a microbial reduction after UVC-LED exposure compared with the control group. Regarding the color, the groups presented an average ΔE (light 0.205 and dark 0.308) compatible with visually imperceptible changes (light < 0.7 and dark < 1.2).

CONCLUSIONS

Irradiation with UV-C LED light decreased the in vitro microbial cell viability of the medical silicone used in facial prostheses, demonstrating initial color stability.

Potential of pulsed light technology for control of SARS-CoV-2 in hospital environments

The emergence of the SARS-CoV-2 infection and its potential transmission through touching surfaces in clinical environments have impelled the use of conventional and novel methods of disinfection to prevent its spreading. Among the latter, pulsed light may be an effective, non-chemical decontamination alternative. Pulsed light technology inactivates microorganisms and viruses by using high intensity polychromatic light pulses, which degrades nucleic acids and proteins. This review describes this technology, compiles and critically analyzes the evidence about the virucidal efficacy of pulsed light technology with view on its potential use against SARS-CoV-2 in touching surfaces in health-care facilities. The efficacy of pulsed light proved against many different kind of viruses allows to conclude that is a suitable candidate to inactivate SARS-CoV-2 as long as the required fluence is applied and the appropriated exposure to contaminated surfaces is guaranteed.

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Pulsed light can inactivate many different types of viruses.

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Its antimicrobial efficacy has been proved in different health care facilities.

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Pulsed light produces fast inactivation and it is ecologically friendly.

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Evidence shows that it should be effective for SARS-CoV-2 inactivation.

Environmental Disinfection of a Dental Clinic during the Covid-19 Pandemic: A Narrative Insight

BACKGROUND

The control of biological hazard risk in health care and dental clinic environments represents a critical point in relation to the Covid-19 infection outbreak and international public health emergency. The purpose of the present review was to evaluate the scientific literature on the no-touch disinfection procedures in dental clinics aiming to limit transmission via airborne particles or fomites using no-touch procedures for environmental decontamination of dental clinics.

METHODS

An electronic database literature search was performed to retrieve research papers about Covid-19 and no-touch disinfection topics including full-length articles, editorials, commentaries, and outbreak studies. A total of 86 papers were retrieved by the electronic research.

RESULTS

No clinical article about the decontamination of a dental clinic during the Covid-19 pandemic was detected. About the topic of hospital decontamination, we found different no-touch disinfection procedures used in hospital against highly resistant organisms, but no data were found in the search for such procedures with respect to SARS-CoV-2: (1) aerosolized hydrogen peroxide, (2) H2O2 vapor, (3) ultraviolet C light, (4) pulsed xenon, and (5) gaseous ozone. One paper was retrieved concerning SARS-CoV-2; 32 documents focused on SARS and MERS. The cleaning and disinfection protocol of health care and dental clinic environment surfaces are essential elements of infection prevention programs, especially during the SARS-CoV-2 pandemic.

CONCLUSION

The decontamination technique that best suits the needs of the dental clinic is peroxide and hypochlorous which can be sprayed via a device at high turbine speed with the ability of producing small aerosol particles, recommendable also for their low cost.

Comprehensive review of guidelines to practice prosthodontic and implant procedures during COVID-19 pandemic

OBJECTIVES

To present a comprehensive review of current literature available on Corona virus disease and dentistry, modifications required in dental and laboratory settings; and recommended disinfection protocols in current scenario. Special emphasis has been given to discuss guidelines for handling different prosthodontic procedures and implications of this pandemic on prosthodontic practice, education and research.

MATERIALS AND METHODS

Relevant literature pertaining to COVID-19 and dentistry was scrutinized on electronic search engines including PubMed, EMBASE and Cochrane. Guidelines given by various organizations, institutions, national and international regulatory bodies and Indian Prosthodontic Society were also consulted to gather information pertaining to the objectives of our review.

RESULTS

and observations: A total of 160 articles including cross-sectional studies, in vitro study, narrative reviews, letters to the editor and opinions were found to be relevant in accordance with our search strategy. Documented literature revealed that Covid-19 pandemic has culminated in serious clinical, financial and psychological implications in the field of dentistry. Certain steps such as adoption of teledentistry, judicious use of protective equipment, use of rubber dams, pre-procedural rinses have been suggested unanimously. However, there is a dearth of evidence-based recommendations in literature. Data regarding consequences of delaying prosthodontic procedures and patients' perspectives is also sparse.

CONCLUSION

The COVID-19 necessitates the need to adopt a balanced approach while treating patients and safeguarding the dental professionals at the same time. Risk-benefit ratio has to be assessed along with stringent following of guidelines and disinfection protocols to combat this unprecedented situation.