Disinfection Time Research Articles

Potential for synergism of sequential UV-NaClO disinfection on ARGs removal in municipal sewage: Effectiveness, kinetics, and mechanisms

Conventional disinfection technologies have limitations in effectively addressing the challenges posed by the emerging pollutant of antibiotic resistance genes (ARGs). To reduce the risk of antibiotic resistance in wastewater treatment plant (WWTP) effluent, this study investigated the effectiveness of ultraviolet (UV) irradiation followed by Sodium hypochlorite (NaClO) (sequential UV-NaClO) disinfection in removing six classes and 18 subtypes of ARGs in the secondary effluent of a municipal WWTP. The study showed that UV disinfection could reduce tetracycline ARGs (TCs-ARGs) subtype tetQ by 0.98 log, while it was ineffective in removing sulfonamide ARGs (SAs-ARGs). NaClO disinfection was very effective in removing ARGs. Increasing the disinfectant dosage is more effective than extending the disinfection time. The highest removal was observed for the SAs-ARGs subtype sul1 with 4.15 log and the β-lactams-ARGs(β-LACs-ARGs) subtype blaCTX-M1 with 3.87 log. Sequential UV-NaClO disinfection has the potential for synergistic effects in disinfection. Sequential UV-NaClO disinfection with a UV dosage of 15 mJ/cm2 and a NaClO dosage of 10 mg/L can effectively remove 1.46 log of the total 18 subtypes of ARGs, which is 0.73 log higher than the removal achieved by standalone UV irradiation at a fluence of 100 mJ/cm2, and equivalent to the results obtained with NaClO disinfection alone at a dose of 30 mg/L. Additionally, sequential UV-NaClO disinfection can reduce the repair efficiency of ARGs. The proposed modified Hom model can be used to analyze the kinetics of sequential UV-NaClO disinfection synergy. Analysis of microbial community structure and co-occurrence of ARGs showed synchronized and consistent removal of ARGs and their potential bacterial hosts. Sequential UV-NaClO disinfection could achieve 99 % removal of more than half of the genera. Overall, our results indicate that sequential disinfection is a promising disinfection technology for disinfecting municipal wastewater and reducing the spread and transfer of ARGs.

Propagación in vitro de Anredera vesicaria

Anredera vesicariais a plant whit high anti-inflammatory activity. The work objective was to establish in vitropropagation of A. vesicaria. Nodal segments were used as explants and two disinfection times in 1% sodium hypochlorite (15 and 20 minutes) were evaluated during in vitroestablishment. Combinations of AG3 (2,5 and 5,0 mg/L) and IAA (0,05 and 0,1 mg/L) were evaluated in the multiplication phase and the effect of IBA (0,5 and 1,0 mg /L) and Pectimorf (1,0 and 5,0 mg/L) for in vitrorooting. Acclimatization was carried out in a mixture of soil-cow manure-zeolite. Disinfection was achieved with 1% sodium hypochlorite for 15 minutes and in vitroestablishment in the MS (1962) culture medium. High values of multiplication and rooting in vitrowere obtained, as well as acclimatization of plants in vitro.

Modified dorsal recumbent position versus lithotomy position for flexible ureteroscopic lithotomy: a multicenter prospective randomized controlled clinical trial.

The lithotomy position (LP) may pose limitations and discomfort for elderly patients and those with a history of lower limb surgery, potentially leading to an increased risk of complications. And the LP is the conventional position during flexible ureteroscopic lithotomy for the treatment of ureteral calculi. However, it has some disadvantages, such as peripheral nerve injury and deep venous thrombosis in the lower limbs, etc. Therefore, we performed a new approach, which is named as modified dorsal recumbent position (MDRP). Currently, there is a lack of systematic analysis and standardization regarding the surgical positioning for flexible ureteroscopic lithotripsy. The objective of the study was to assess whether there were any disparities in the overall duration of the procedure when comparing the MDRP with the LP. The investigation of the optimal position for flexible ureteroscopic lithotomy is essential for enhancing patient safety and comfort. This is a prospective, multicenter, randomized clinical trial. A total of 144 patients with renal or ureteral calculi from April 2021 to June 2022 were enrolled. Eligible patients were randomized to the MDRP group (n=72) or LP group (n=72). The patient's demographics, the placement of the surgical position (time of position placement, time of disinfection and towel laying, time of position return, degree of medical fatigue) and the operation safety (time of operation, time of ureteroscope from bladder neck to ureteral orifice, heart rate, blood pressure) of two groups were compared and analyzed. Between the two groups, the body positioning time (93.8±31.6 vs. 134.8±40.1 s, P=0.02), operation time (71.8±36.7 vs. 77.7±48.6 min, P=0.04), the time from the bladder neck to the ureteral orifice of the flexible ureteroscope spent by the doctors (3.4±4.7 vs. 10.3±14.7 s, P<0.001) and incidence rate of patient's lower limb soreness (19.4% vs. 49.7%, P=0.01) in the MDRP group were significantly shorter than those in the LP group. However, there was no significant difference in the stone removal rate (87.6% vs. 85.4%, P=0.09) or postoperative hospitalization days (4.3±1.4 vs. 4.1±1.6 d, P=0.08) between the two groups. This trial showed that the MDRP could not only effectively shorten the operation time, shorten the time from the bladder neck to the ureteral orifice of the ureteroscopic lithotripsy, but also place the patient's body in a functional position, stabilize the blood pressure during the operation, improve the comfort of the patient. Chinese Clinical Trial Registry (No. ChiCTR2100053416).

Spraying zinc oxide nanoparticles on pistachios (Pistacia vera L.) for preservation in cold storage

ABSTRACT The ability of zinc oxide nanoparticles to extend the shelf life of fresh pistachios in polyethylene packages in cold storage was evaluated. Independent variables were the type and concentration of the disinfectant (0.5%, 1%, 1.5%, and 2% nano-ZnO and 2% peracetic acid) and storage time (at harvest, 25, 50 and 75 days after harvest). Aflatoxin was not detected in the kernels of the disinfectant treatments after storage. A decrease occurred in firmness, chlorophylls and carotenoids in hulls and kernels over time. Phenolics and flavonoids of kernels decreased, parallel to a decrease in weight. Nano-ZnO (2%) prevented this reduction well. In hulls and kernels, nano-ZnO (2%) revealed the highest anthocyanin. Antioxidant activity in kernels remained stable or even increased in response to ZnO (1.5%) on day 75. All ZnO treatments prevented ion leakage while limiting hydrogen peroxide and malondialdehyde production in hulls. Peracetic acid reduced polyphenol oxidase activity on 75th day. ZnO (1% and 1.5%) and peracetic acid increased phenylalanine ammonia lyase activity. On 75th day, ZnO-treated samples had higher peroxidase activity. All ZnO treatments, especially 1.5% and 2%, prevented the loss of quality in hulls, shells, taste, and aroma. Nano-ZnO (2%) can be recommended for fresh pistachio preservation in cold storage.

Efficient In Vitro Propagation of Turpinia arguta and Quantitative Analysis of Its Ligustroflavone and Rhoifolin Content

Turpinia arguta is an excellent medicinal plant mainly used for the treatment of pharyngitis, tonsillitis, and tonsillar abscesses. However, an efficient regeneration protocol using tissue cultures for T. arguta does not exist. Its main medicinal constituents are flavonoids, particularly ligustroflavone and rhoifolin. Here, we aimed to establish a tissue culture system for T. arguta for the first time using annual stem segments with axillary buds harvested from the field of the Jiangxi Academy of Forestry as explants by dynamically determining the accumulation of effective functional components in the tissue culture plantlets. Orthogonal tests were conducted to compare the effects of different explant disinfection times, media, and exogenous hormone ratios on the induction of the axillary bud growth, successional proliferation, and rooting of T. arguta stem segments. The best explant disinfection effect was achieved by disinfecting the T. arguta explant with 75% ethanol for 50 s, followed by 0.1% mercuric chloride (HgCl2) for 6 min, and the optimal media for successional proliferation and rooting were Murashige and Skoog (MS) + 0.2 mg/L of 6-benzyladenine (6-BA), + 0.03 mg/L of naphthaleneacetic acid (NAA), and ½ MS + 2.5 mg/L of indole-3-butyric acid + 0.5 mg/L of NAA, respectively. The detection of ligustroflavone and rhoifolin in tissue culture plantlets 0, 3, and 5 months after transplanting showed a significant increasing trend and eventually exceeded the content requirements of the 2020 Edition ofChinese Pharmacopoeia for T. arguta. Our findings provide, for the first time, an effective tissue culture system for T. arguta, thereby providing important information to support the germplasm preservation, innovation, and application of T. arguta in the future.

Effective of different industrial disinfection in subzero cold-chain environment

Effective disinfection methods are crucial in the cold chain transportation process of food due to the specificity of temperature and the diversity of contaminated flora. The objective of this study was to investigate the sanitizing effect of different disinfectants on various fungi at – 20 °C to achieve accurate disinfection of diverse bacterial populations. Peracetic acid, hydrogen peroxide, and potassium bisulfate were selected as low-temperature disinfectants and were combined with antifreeze. The sanitizing effect of these cryogenic disinfectants on pathogens such as Bacillus subtilis black variant spores (ATCC9372), Staphylococcus aureus (ATCC 6538), Candida albicans (ATCC 10231), Escherichia coli (8099), and poliovirus (PV-1) was sequentially verified by bactericidal and virus inactivation experiments. After a specified time of disinfection, a neutralizing agent was used to halt the sanitizing process. The study demonstrates that different disinfectants exhibit selective effects during the low-temperature disinfection process. Peracetic acid, hydrogen peroxide, and potassium monopersulfate are suitable for the low-temperature environmental disinfection of bacterial propagules, viruses, and fungal contaminants. However, for microorganisms with strong resistance to spores, a low-temperature disinfectant based on peracetic acid should be chosen for effective disinfection treatment. Our results provide a valuable reference for selecting appropriate disinfectants to sanitize various potential pathogens in the future.

Regression model and pathways of halonitromethane formation from amino acids in the presence of bromide ion under UV/monochloramine disinfection

Halonitromethanes (HNMs) including chlorinated and brominated HNMs, a category of nitrogenous disinfection by-products with high toxicity, were formed from amino acids (AAs) in the presence of bromide ion (Br-) under UV/monochloramine (UV/NH2Cl) disinfection. This study developed a regression model using water characteristics (pH, HCO3– and Br-) and disinfection conditions (disinfection time and NH2Cl doses) to predict HNM formation from AAs (tyrosine (Tyr), tryptophan (Trp) and aspartic acid (Asp)) in the presence of Br- under UV/NH2Cl disinfection. Main contributors to the abatement of Tyr and Trp were UV (6.1%-18.7%), HO (18.5%-62.3%), Cl2− (0.3%-17.9%), Br (2.4%-41.3%, kBr•,AA=∼109-1010 M−1·s−1), Br2− (1.3%-11.0%, kBr2•-,AA=∼108-109 M−1·s−1), NO (2.6%-43.0%) and CO3− (0%-43.2%) based on the first-principle kinetic model of UV/NH2Cl/Br- process, while the removal ratio of Asp was low. It was responsible for higher HNM concentrations from Tyr and Trp than those from Asp. Due to the decline in HNM concentrations with prolongation of reaction time, HNM concentrations were considered as the quadratic function of disinfection time with coefficients related to water characteristics and NH2Cl doses. The regression model with backward stepwise regression described HNM formation well. After introducing specific UV absorbance at 254 nm (SUVA254) and interaction terms associated with SUVA254, HNM formation from three AAs was successfully predicted by one regression equation (R2 = 0.91, mean absolute error = 0.46, mean relative error = 37%, root-mean-square error = 0.81). Using the optimal regression model, increasing NH2Cl doses was found to advance the peak time for HNM formation. Besides, obtained heatmaps of HNM formation revealed that a high NH2Cl dose with a high UV dose or low NH2Cl dose helped to limit HNM formation. Lastly, the possible formation pathways of HNMs were presented.

Hydroquinine Enhances the Efficacy of Contact Lens Solutions for Inhibiting Pseudomonas aeruginosa Adhesion and Biofilm Formation.

P. aeruginosa is one of the most common bacteria causing contact lens-related microbial keratitis (CLMK). Previous studies report that disinfecting solutions were ineffective in preventing biofilm formation. Solutions containing novel natural agents may be an excellent alternative for reducing the risk of CLMK. Here, we investigate the disinfecting properties of hydroquinine in combination with multipurpose solutions (MPSs) to prevent P. aeruginosa adhesion and biofilm formation. We examined the antibacterial, anti-adhesion, and anti-biofilm properties of hydroquinine-formulated MPSs compared to MPSs alone. Using RT-qPCR, hydroquinine directly affected the expression levels of adhesion-related genes, namely, cgrC, cheY, cheZ, fimU, and pilV, resulting in reduced adhesion and anti-biofilm formation. Using ISO 14729 stand-alone testing, hydroquinine met the criteria (>99.9% killing at disinfection time) against both P. aeruginosa reference and clinical strains. Using the crystal violet retention assay and FE-SEM, MPSs combined with hydroquinine were effective in inhibiting P. aeruginosa adhesion and destroying preexisting biofilms. This report is the first to highlight the potential utility of hydroquinine-containing formulations as a disinfecting solution for contact lenses, specifically for inhibiting adhesion and destroying biofilm. These findings may aid in the development of novel disinfectants aimed at combating P. aeruginosa, thereby potentially reducing the incidence of CLMK.

Are protective measures against Covid-19 still active in orthodontic practices? A cross-sectional online survey of French orthodontists three years on from the pandemic.

The Covid-19 epidemic has imposed profound changes on the practice of orthodontics. It was in this anxiety-inducing context that drastic measures were imposed on orthodontists. The main aim of this online survey is to highlight the measures that are still in place in French orthodontic practices three years after the emergence of the pandemic. A cross-sectional online survey was distributed to French orthodontists from march to June 2023. The questionnaire, consisting of 32 questions, was divided into five sections covering habits before and after the pandemic, and the feelings of professionals. In this survey 230 complete answers were recorded. Three years later, the daily pace had returned to its pre-crisis level. Disinfection and aeration times were still present (p < 0.001). Orthodontists maintained and generalized the use of protective glasses (p = 0.17) and visors (p < 0.001). The same was true for the FFP2 mask and its frequency of change, as well as rigorous hand washing. Finally, the dedicated layout of the practices was maintained: protective screen, filtration system, supply of SHA, travel paths, removal of magazines (for all, p < 0.001). This study shows that the professional practices imposed by the Covid-19 crisis have been adopted by the majority of French orthodontists, and now appear to be anchored in their routine practice. opinion n°2023-004, dated 01.25.2023.

The Impact of Time and Temperature of Operation on the Characteristics of High-Power UVC LEDs and Their Disinfection Efficiency

Disinfection and sterilization based on the use of UVC radiation are the key technologies ensuring health and safety. Their reliability depends on assuring the effectiveness of the performed process. In recent years, the rapid development of LED sources emitting high-power radiation in the UVC range has been observed, and there is a growing interest in using them in a variety of smart applications, mostly because they are easy to control, do not contain hazardous substances, and there are prospects to increase their energy efficiency. However, the literature does not provide enough knowledge on the reliability of disinfection with high-power UVC LEDs. This research aims to present a methodology of linking the performance characteristics with assessing the forecasted changes in the disinfection efficiency of exemplary UVC high-power LEDs caused by thermal and temporal changes in their characteristics. Based on the performed degradation test, the impact of the temperature and time of operation of the high-power UVC LEDs on the effectiveness of disinfection was evaluated, and the required disinfection times for exemplary pathogens were calculated. The results reveal a strong influence of the time of operation of high-power UVC LEDs on the disinfection reliability caused by the degradation of their optical power but with a low significance of wavelength shift.

A New Protocol to Mitigate Damage to Germination Caused by Black Layers in Maize (Zea mays L.) Seeds

Maize seeds harvested in the field have higher vitality than those harvested in greenhouses but have higher contamination rates in terms of fungal or bacterial infection. It is important to disinfect maize seeds before sowing because seeds are a source of infection and damage crop production. In this study, we aimed to provide an efficient seed sterilization method to manage fungal or bacterial infections of field-harvested maize seeds. The optimized sterilization protocol was set up according to the disinfectant liquid immersion time, inverting RPM (rotations per minute), number of seeds, and black layer removal. We put 20 grains of maize seeds in 100% commercial bleach disinfectant containing 4–5% NaClO and performed 20 min of inversion at 45 RPM. After standing without inverting for the next 25 min in the sterile hood, inversion at 45 RPM for another 40 min was performed. By using this protocol, microorganisms occurred at a low rate with an average of 11.7%. Moreover, it was shown that microorganisms occurred at the lowest rate (average of 0.29% of seeds) when the black layer was removed. In addition, this sterilization method did not affect the growth and development of maize plants. These results revealed that black layer removal from maize seeds is a highly efficient, easy, and inexpensive sterilization method and can be used for seeds of various maize lines.

Halogenated aliphatic and phenolic disinfection byproducts in chlorinated and chloraminated dairy wastewater: Occurrence and ecological risk evaluation

The increasing demand for dairy products has led to the production of a large amount of wastewater in dairy plants, and disinfection is an essential treatment process before wastewater discharge. Disinfection byproducts (DBPs) in disinfected dairy wastewater may negatively influence the aquatic organisms in receiving water. During chlorine and chloramine disinfection of dairy wastewater, the concentrations of aliphatic DBPs increased from below the detection limits to 485.1 μg/L and 26.6 μg/L, respectively. Brominated and iodinated phenolic DBPs produced during chlor(am)ination could further react with chlorine/chloramine to be transformed. High level of bromide in dairy wastewater (12.9 mg/L) could be oxidized to active bromine species by chlorine/chloramine, promoting the formation of highly toxic brominated DBPs (Br-DBPs), and they accounted for 80.3% and 71.1% of the total content of DBPs in chlorinated and chloraminated dairy wastewater, respectively. Moreover, Br-DBPs contributed 49.9–75.9% and 34.2–96.4% to the cumulative risk quotient of DBPs in chlorinated and chloraminated wastewater, respectively. The cumulative risk quotient of DBPs on green algae, daphnid, and fish in chlorinated wastewater was 2.8–11.4 times higher than that in chloraminated wastewater. Shortening disinfection time or adopting chloramine disinfection can reduce the ecological risks of DBPs.

Effect of peeling, cutting, or shredding of lettuce, carrot, or potato on the efficacy of chlorine disinfection.

Minimally processed vegetables are washed and subsequently disinfected by immersion in water solutions with antimicrobials which reduce the initial pathogenic or spoilage microbial load. Chlorine remains one of the most widely used disinfectants for vegetables and hence the importance of studying its properties. The aim of this study was to evaluate the effect of peeling, cutting, and shredding on the effectiveness of chlorine (200 ppm) as a disinfectant in lettuce, carrot, and potato. Three independent repetitions of each experiment were completed, and data was statistically analyzed. Results showed that the maintenance of the chlorine concentration in the disinfectant solution, over time, depended on the vegetables' preliminary processing technique (whole, peeled, cut, or shredded) (p < 0.05). In general, the disinfection treatments studied reduced Escherichia coli by 1-8 logs. The addition of chlorine in the disinfectant solution allowed greater reduction in E. coli than using water immersions (p < 0.05) and disinfection times longer than 5 min did not improve these microbiological reductions (p>0.05). The vegetables' subdivision (whole, peeled, cut, or shredded) can affect both E coli's reduction and the vegetables' residual chlorine concentration. No trend was observed in terms of sensory differences and their relationship to the vegetables' processing and disinfection. These results suggest that each facility must validate its disinfection processes, according to the conditions established on site and reduction goals related to initial microbial counts, vegetables' quality, processing operations, and other important aspects.

Portable IoT-Based Disinfection Box

The COVID-19 pandemic is an ongoing global health event that began in 2019. It is caused by a novel strain of coronavirus known as SARS-CoV-2. Bacteria and viruses can cause illness in human. Therefore, a Portable IoT-based Disinfection Box is developed in this work to disinfect small electronic devices such as smartphone, smartwatch or even a 13-inch tablet, that may come into contact with bacteria and viruses. There are three special features of this Disinfection Box which are the timer itself, Web Interface Monitoring, portable and spacious with dimensions of 29 × 18 × 14 cm3. The ESP32 Wi-Fi module with NodeMCU-32S Base module as a microcontroller is used in this work and it controls the 2-channel Relay in order to turn ON and OFF the UV-C LED light strip. Besides that, it is also connected to the LCD display with I2C module to display the real-time of disinfection process. The Dashboard of Arduino IoT Cloud allows the user to control and monitor the operation of disinfection process. When a small electronic device is placed inside the Disinfection Box, UV-C LED light strip is turned on to begin the disinfection process. The effectiveness of the UV-C LED light strip is investigated by using the Petri dish with agar. It is shown from the experimental procedures that 10-minute disinfection time provided by the Disinfection Box is sufficient to disinfect small electronic devices such as smartphone and smartwatch. This is based on the great reduction of bacteria colonies on the agar in Petri dish after being kept in a dark place with room temperature for 4 days.

The Virucidal Effect of the Chlorination of Water at the Initial Phase of Disinfection May Be Underestimated If Contact Time Calculations Are Used.

For the microbiological safety of drinking water, disinfection methods are used to remove or inactivate microorganisms. Chlorine and chlorine dioxide are often used as disinfectants in drinking water treatment plants (DWTPs). We investigated the effectiveness of these chemicals in inactivate echovirus 30 (E30), simian 11 rotavirus (RV SA11), and human adenovirus type 2 (HAdV2) in purified water from a DWTP. Within two minutes of contact, chlorine dioxide inactivated E30 by 4-log10, RV SA11 by 3-log10, and HAdV2 could not be detected, while chlorine reduced E30 by 3-log10, RV SA11 by 2-3log10, and HAdV2 by 3-4log10. However, viral genomes could be detected for up to 2 h using qPCR. The CT method, based on a combination of disinfectant concentration and contact time, during such a short initial phase, is problematic. The high concentrations of disinfectant needed to neutralize organic matter may have a strong immediate effect on virus viability. This may lead to the underestimation of disinfection and overdosing of disinfectants in water with organic contamination. These results are useful for the selection of disinfection systems for reuse of treated wastewater and in the risk assessment of water treatment processes using chlorine and chlorine dioxide.

Safe reuse of wastewater: Effect of disinfection methods on microbial community

Performic acid (PFA), a new generation of disinfectant, has shown outstanding performance for wastewater treatment. However, the effect of PFA on wastewater microbial community changes as well as the differences in comparison to the commonly disinfectants used are poorly documented. We provide an overview of the PFA effect and that of chlorine and UV, two commonly used disinfectants, on microbial community diversity and structure. The study was performed using wastewaters from three municipal wastewater treatment plants (WWTPs) processed by activated sludge, lagoon and reed beds, and biofilter. We focused on disinfection of pathogen microorganisms, identifying sensitive and resistant bacteria to disinfectants that can serve as biomarkers for evaluating the disinfectant performances. As well, we investigated the modifications of microbial functions after treatment by functional predictive analysis. The more efficient E. coli inactivation was obtained with initial concentration of 4 mg/L of PFA with 15 min disinfectant contact time that achieved 95.71–99.99% inactivation efficiency. Although the origin of wastewater was the main factor determining the microbial community diversity and composition, the microbial communities were specific to the disinfectant used. Linear discriminant analysis Effect Size (LEfSe) identified 18 and 10 biomarkers, including pathogenic microorganisms affiliated to Chromobacterium, Flavobacterium, Aeromonas, Enterobacteriaceae, Escherichia_Shigella and Fusobacteriaceae, which were sensitive to PFA, while being resistant to chlorine and/or UV. Consistently, the predicted bacterial functional patterns diverged according to the wastewater origin and the disinfectant used. Pathogen microorganisms were more sensitive to PFA than the other treatments, demonstrating its potential for implementing a safe reuse of wastewater.

Glove disinfection and aseptic technique: Creating a schema for the cleanroom and laboratory

There are different elements that contribute to good aseptic technique within the cleanroom and the laboratory. One such element is the donning of gloves (1), handling items appropriately, and keeping gloves regularly disinfected (2). Glove disinfection is an essential step for bacteriological control, although how successful control is maintained is dependent upon the type of disinfectant (these are generally alcohols for gloved hands) (3), frequency of application, volume of disinfectant, application technique and the contact time. Other variables include purchasing gloves of a suitable material and design, and appropriate training. Aa an added control with more critical areas, the gloves are pre sterilised before donning (often purchased sterile by radiation or ethylene oxide). As with other types of disinfection, the aim is not ‘sterilisation’ but to bring any bacterial density present on the gloves down to a level that is as low as possible (what is sometimes referred to as the "irreducible minimum") (4). Assessment, when required, is commonly through the use of agar contact plates onto the fingertips of each gloved hand (four fingers and the thumb) to create the ‘finger plate’ or ‘finger dab’. To avoid false negatives, the agar needs to be formulated with an appropriate disinfectant neutraliser. For cleanroom and laboratory managers seeking to maximise the maintenance of asepsis, glove control is an important element. This should take the form of a good practice schema and for this to be transitioned into a training module, supported by regular prompts in practice. In terms of what such a schema should look like, this article appraises the research that underpins an appropriate glove ‘sanitisation’ schema. This includes the central concerns of when and how effective glove disinfection is to be achieved (5). The key findings are that a 30 second disinfection time is suitable for both cleanroom and laboratory operations, provided a suitable technique is deployed and an alcohol-based disinfectant used. However, controls need to be in place to avoid the over disinfection of gloves since repeated applications increase the likelihood of microperforations occurring and thereby effective glove disinfection needs to be supported by a regular glove change procedure.

Operating room disinfection: operator-driven ultraviolet ‘C’ vs. chemical treatment

In operating room (OR) surfaces, Nosocomial pathogens can persist on inanimate surfaces for long intervals and are highly resistant to traditional surface cleaning. This study compares traditional chemical operating room terminal disinfection to a unique operator-driven device that emits germicidal UV light at short distance onto vertical and horizontal surfaces. A randomized crossover analogous protocol assigned 40 end-of-day operating rooms into either group A (chemical then UVC treatments) or group B (UVC then chemical treatments). Initial Staphylococcal cultures were obtained prior to disinfection treatment, after the first treatment, and after the second treatment at 16 most commonly contaminated sites to represent overall room contamination. Success was defined as no growth and failure as 1 or more colony forming units. Thoroughness of chemical treatment vs UVC treatment was compared and used to determine if the second treatment was additive to the first treatment within each group. The operator driven UVC device outperformed chemical treatment in reducing the number of contaminated sites in the OR by more than half (P<0.001). Operator-driven UVC reduced contaminated sites after chemical treatment by nearly half (P<0.001). In contrast, chemical treatment after operator-driven UVC did not significantly reduce the number of contaminated sites. The mean employee time of disinfection for chemical treatment was 49 minutes and for the operator-driven UVC emitter 7.9 minutes (P<0.001). This study demonstrates that addition of an operator-driven UVC emitter to OR rooms between cases could be helpful in overall decreasing the number of contaminated sites.

Development of Far-UVC-Based Surface Disinfection Prototype for Public Buses

This paper presents a prototype of a disinfection system for public transport specifically aiming to disinfect surfaces contaminated with the SARS-CoV-2 virus on buses using 222 nm wavelength far-ultraviolet light (far-UVC). Our study involved testing the developed technical system installed in a 12 m long M3 category urban bus, an investigation of optimal far-UVC light angles, and the determination of disinfection parameters for bus seat disinfection. The study identified the ideal positioning of a light source for effective disinfection and analyzed three disinfection scenarios, considering zone coverage, disinfection time, and energy demand. A subsystem employing real-time occupancy monitoring enhances the disinfection process in crowded areas of buses. An energy efficiency assessment model is proposed for optimizing energy consumption. Furthermore, the energy consumption analyses in different disinfection scenarios provide valuable insights for optimizing energy usage in public transport disinfection.

Experimental study on the microwave radiation disinfection of E. coli on SiC composite filter

Filter is an important component in the air-conditioning system. The airborne microorganisms can be intercepted and further multiply on the filter, which might cause a secondary pollution. The present work proposed a SiC composite filter (SCF), namely combining the filter with the absorbing material SiC. The disinfection efficiency (η) and mechanism of the microwave radiation method (MRM) on E. coli and S. aureus attached to the SCF were experimentally explored. The impacts of the microwave power (P) and disinfection time (t) on η were investigated. The results show that the SCF can be heated well by the microwave, but the normal filter (NF) cannot. The MRM can effectively and rapidly disinfect bacteria on the SCF at a sufficiently high P and an appropriate t. Generally, η increases with P and t. Under a specific P, η can be only increased with t at a certain range and a peak η might be reached. When this peak is achieved, η will not be further increased with t. The disinfection by the MRM is attributed to the thermal and non-thermal effects. Specially, at P = 600 W and t = 10 min, the non-thermal effect contributes about 89.6% to the disinfection of the E. coli and about 43.1% to the S. aureus. A universal relationship between η and temperature is given for E. coli and S. aureus to predict η at various P and t. Finally, the effective temperatures required by the MRM to satisfactorily disinfect bacteria on the SCF are identified, i.e., about 41 °C for E. coli and 71 °C for S. aureus.