Surface Disinfection Research Articles

Investigations of the UVC 222 NM air cleaning system in an air-conditioned room

Far-Ultraviolet-C (far-UVC) 222 nm was introduced during the Covid-19 pandemic to disinfect the airborne pathogens, particularly SARS-CoV-2. Although far-UVC 222 nm has shown promising results in surface disinfection, its efficacy in air disinfection remains uncertain due to additional variables in air. This study investigated the efficacy of far-UVC 222 nm UVGI in air disinfection experimentally, using total plate count, and input the measured far-UVC intensity into the computational fluid dynamic model to predict infection risk using the Wells-Riley model. Experimental results indicated that after 1 h of far-UVC irradiation, an equivalent far-UVC dosage of 21.31 J/m2, airborne bacteria concentration was reduced by 44.4 %–74.1 %, while airborne fungal concentration showed a marginal reduction. In a recirculating air-conditioned room, a 20 W far-UVC fixture installation, referred to as Case 1, demonstrated the highest available dosage of 7.66 % difference compared to Case 2. The use of far-UVC in Case 1 can reduce the risk of infection for the influenza H1N1, SARS-CoV-2, and Mycobacterium tuberculosis by 54.48 %, 60.06 %, and 83.73 %, respectively. The study suggests installing far-UVC near the recirculating air-conditioner supply air jet and away from surrounding walls for optimum effectiveness. These results provide recommendations for alternatives to upper-room UVGI, offering a viable option for continuous room air and surface disinfection.

Genetic determinants of increased sodium hypochlorite and ciprofloxacin susceptibility in Pseudomonas aeruginosa PA14 biofilms

Reactive chlorine species (RCS) like sodium hypochlorite (NaOCl) are potent oxidizing agents and widely used biocides in surface disinfection, water treatment, and biofilm elimination. Moreover, RCS are also produced by the human immune system to kill invading pathogens. However, bacteria have developed mechanisms to survive the damage caused by RCS. Using the comprehensive Pseudomonas aeruginosa PA14 transposon mutant library in a genetic screen, we identified a total of 28 P. aeruginosa PA14 mutants whose biofilms showed increased susceptibility to NaOCl in comparison to PA14 WT biofilms. Of these, ten PA14 mutants with a disrupted apaH, PA0793, acsA, PA1506, PA1547, PA3728, yajC, queA, PA3869, or PA14_32840 gene presented a 4-fold increase in NaOCl susceptibility compared to wild-type biofilms. While none of these mutants showed a defect in biofilm formation or attenuated susceptibility of biofilms toward the oxidant hydrogen peroxide (H2O2), all but PA14_32840 also exhibited a 2–4-fold increase in susceptibility toward the antibiotic ciprofloxacin. Further analyses revealed attenuated levels of intracellular ROS and catalase activity only for the apaH and PA1547 mutant, providing insights into the oxidative stress response in P. aeruginosa biofilms. The findings of this paper highlight the complexity of biofilm resistance and the intricate interplay between different mechanisms to survive oxidative stress. Understanding resistance strategies adopted by biofilms is crucial for developing more effective ways to fight resistant bacteria, ultimately contributing to better management of bacterial growth and resistance in clinical and environmental settings.

Plumbagin enhances antimicrobial and anti-biofilm capacities of chlorhexidine against clinical Klebsiella pneumoniae while reducing resistance mutations.

With the widespread misuse of disinfectants, the clinical susceptibility of Klebsiella pneumoniae (K. pneumoniae) to chlorhexidine (CHX) has gradually diminished, posing significant challenges to clinical disinfection and infection control. K. pneumoniae employs overexpression of efflux pumps and the formation of thick biofilms to evade the lethal effects of CHX. Plumbagin (PLU) is a natural plant extract that enhances membrane permeability and reduces proton motive force. In this study, we elucidated the synergistic antimicrobial activity of PLU in combination with CHX, effectively reducing the MIC of CHX against K. pneumoniae to 1 µg/mL and below. Crucially, through crystal violet staining and confocal laser scanning microscopy live/dead staining, we discovered that PLU significantly enhances the anti-biofilm capability of CHX. Mechanistically, experiments involving membrane permeability, alkaline phosphatase leakage, reactive oxygen species, and RT-qPCR suggest that the combination of PLU and CHX improves the permeability of bacterial inner and outer membranes, promotes bacterial oxidative stress, and inhibits oqxA/B efflux pump expression. Furthermore, we conducted surface disinfection experiments on medical instruments to simulate clinical environments, demonstrating that the combination effectively reduces bacterial loads by more than 3 log10 CFU/mL. Additionally, results from resistance mutation frequency experiments indicate that combined treatment reduces the generation of resistant mutants within the bacterial population. In summary, PLU can serve as an adjuvant, enhancing the anti-biofilm capability of CHX and reducing the occurrence of resistance mutations, thereby extending the lifespan of CHX.IMPORTANCEAs disinfectants are extensively and excessively utilized worldwide, clinical pathogens are progressively acquiring resistance against these substances. However, high concentrations of disinfectants can lead to cross-resistance to antibiotics, and concurrent use of different disinfectants can promote bacterial resistance mutations and facilitate the horizontal transfer of resistance genes, which poses significant challenges for clinical treatment. Compared with the lengthy process of developing new disinfectants, enhancing the effectiveness of existing disinfectants with natural plant extracts is important and meaningful. CHX is particularly common and widely used compared with other disinfectants. Meanwhile, Klebsiella pneumoniae, as a clinically significant pathogen, exhibits high rates of resistance and pathogenicity. Previous studies and our data indicate a significant decrease in the sensitivity of clinical K. pneumoniae to CHX, highlighting the urgent need for novel strategies to address this issue. In light of this, our research is meaningful.

Parental knowledge, attitudes and practices regarding safe handling and disposal of alcoholbased hand sanitizers and surface disinfectants in urban Sri Lanka

Parental knowledge, attitudes and practices regarding safe handling and disposal of alcoholbased hand sanitizers and surface disinfectants in urban Sri Lanka

Bushy-Tailed QACs: The Development of Multicationic Quaternary Ammonium Compounds with a High Degree of Alkyl Chain Substitution.

Quaternary ammonium compounds have served as a first line of protection for human health as surface disinfectants and sanitizers for nearly a century. However, increasing levels of bacterial resistance have spurred the development of novel QAC architectures. In light of the observed reduction in eukaryotic cell toxicity when the alkyl chains on QACs are shorter in nature (≤10 C), we prepared 47 QAC architectures that bear multiple short alkyl chains appended to up to three cationic groups, thus rendering them "bushy-tailed" multiQACs. Antibacterial activity was strong (often ~1-4 μM) in a varied set of bushy-tailed architectures, though observed therapeutic indices were not significantly improved over QAC structures bearing fewer and longer alkyl chains.

Surface Cleaning with a Microfiber Cloth and Water followed by Ultraviolet-C Light Exposure Achieves Non-Inferior Disinfection of a Pathogenic Staphylococcus aureus Strain versus Use of Germicidal Wipes.

We hypothesized that ultraviolet-C (UV-C) irradiation (Surfacide, Waukesha, WI) following use of microfiber cloths (Sanny Shop LLC, Longmont, CO) soaked in waterwould be noninferior to surface disinfection wipes containing a quaternary ammonium compound and alcohol (PDI Healthcare, Woodcliff Lake, NJ)for the pathogenic Staphylococcus aureus (S. aureus) sequence type 5 (ST5). This was a randomized laboratory study of disinfection approaches for S. aureusST5. A total of 270 polycarbonate slides loaded with ST5 were prepared for the standard surface disinfection group (N=18) and water-soaked microfiber cloths and UV-C treatment group (N=144), along with positive and negative microbiological controls. All 18 samples of S. aureus ST5 bacteria treated with standard chemical wipes showed complete disinfection (colony forming units (CFU) = 0). All 144 treatments with water-soaked microfiber wipes followed by UV-C exposure showed complete disinfection (CFU =0) regardless of soiling, height from the floor, or orientation to the emitters. The upper 95% exact one-sided confidence limit for any CFU >0 was 2.1%. These data affirm our hypothesis that surface wiping with a damp cloth followed by triangular UV-C irradiation delivery is noninferior to surface disinfection for S. aureusST5 using germicidal wipes, even when UV-C is compromised by height from the floor and orientation to the emitters and surface disinfection is targeted. Removing bioburden with chemical-free microfiber cloths followed by triangular UV-C delivery is a noninferior strategy to targeted surface disinfection with chemical disinfecting wipes for the pathogenicS. aureusST5 strain in the laboratory setting.

Investigation of the disinfection efficiency of commercial hydrogen peroxide, chlorine dioxide, and chlorine disinfectant on different surfaces.

The disinfection efficiency of disinfectants differs in specific conditions. This study aimed to investigate the disinfection efficiency of commercial hydrogen peroxide, chlorine dioxide, and chlorine disinfectant on real field surfaces and provide data for precise disinfection. Simulated field disinfection and field disinfection methods were conducted to quantitatively evaluate the disinfection efficiency of hydrogen peroxide, chlorine dioxide, and sodium dichloroisocyanurate. The log10 reduction of biological indicators, Escherichia coli (ATCC 8099) and Staphylococcus aureus (ATCC 6538), was calculated. Next, the reduction in natural bacteria on the surfaces of a food production and processing workshop and a biosafety laboratory was determined. The 3 commercial disinfectants evaluated were effective against E coli and S aureus, with a reduction of more than 3.00 log10 colony-forming units/mL tested for an exposure time of 15 minutes with 3.5% hydrogen peroxide, 100 mg/L chlorine dioxide, and 250 mg/L sodium dichloroisocyanurate. The natural load in the food production and processing workshop decreased by more than 90% using 10.5% hydrogen peroxide with an exposure time of 30 minutes. The same disinfection level in the biosafety level 2 laboratory was achieved by 500 mg/L chlorine dioxide at an exposure time of 60 minutes and 450 mg/L sodium dichloroisocyanurate at 60 minutes. This study provides a reference for precise disinfection of surfaces in the food industry and biosafety laboratories.

Investigations on the surface disinfection efficacy of far-UVC 222nm germicidal irradiance device in a controlled environment and field test.

The Covid 19 pandemic has significantly affected the health, economy, and social impact of humanity. The continuous mutations of the virus variants have accelerated the demand for scientific research on disinfection techniques for a safer indoor environment. Among all the available surface disinfection techniques, ultraviolet germicidal irradiance at 254nm wavelength has been proven for its disinfection efficacy; however, its usage is limited to unoccupied conditions due to the risk of ultraviolet exposure. This study investigated the efficacy of far-UVC-222nm experimentally in both controlled environment and field setting. Staphylococcus epidermidis and Mycobacterium smegmatis were employed for surface disinfection in both the laboratory and a meeting room. Total plate count was used to determine the disinfection efficacy by a 20W unfiltered far-UVC lamp. At 1.1 µW/cm2 far-UVC irradiation, a 1-log10 reduction of Staphylococcus epidermidis and Mycobacterium smegmatis contamination on tabletop can be achieved by 31.3min and 101.8min of far-UVC irradiation, respectively. Other pathogens of interest such as Staphylococcus aureus, Mycobacterium tuberculosis, Legionella pneumophila, SARS-CoV-2, and the Measles virus were also referred and compared in this study. This study carefully examined how far-UVC irradiation performs effectively for surface disinfection in a real meeting room setting. The results offer useful recommendations for alternatives to upper-room ultraviolet germicidal irradiance for continuous disinfection within the ultraviolet threshold limit value, with the goal of preventing the spread of any diseases in the future.

Coconut Water (Cocos nucifera L.) and Yeast (Saccharomy cescerevisiae) Infused With Papaya (Carica papaya Linn.) Seeds and Leaves as an Alternative Surface Disinfectant

This investigation presents an eco-friendly disinfectant formulation, integrating coconut water, yeast, and extracts from papaya seeds and leaves as alternative components. Under the Republic Act No. 6969 or the Toxic Substances and Hazardous and Nuclear Wastes Control Act of 1990, which underscores the imperative to manage toxic substances for environmental protection. This study aims to address ecological concerns associated with traditional disinfectants. Framed within a true experimental design, the research evaluated the efficacy of the disinfectant. The product, composed of a 7:3 ratio of fermented coconut water with yeast, and papaya extracts respectively; underwent rigorous laboratory assessments, including pH levels, solubility, and disinfecting capacity evaluations. The focus of the study pertains to the experimentation of disinfectant concentrations of 70%, 90%, and 100% to determine the optimal concentration for maximum efficacy. Results indicated water solubility, a pH level adequate for microorganism elimination on surfaces, and significant disinfecting capacity, aligned with the Centers for Disease Control and Prevention (CDC) standards. The study implicates the use of 100% pure concentration of the disinfectant, recommends it as a promising alternative for household applications. This research contributes to the discourse on sustainable disinfection practices guided by the United Nation’s Sustainable Development Goals no. 13 – Climate action.

Antifungal Mechanism of Ruta graveolens Essential Oil: A Colombian Traditional Alternative against Anthracnose Caused by Colletotrichum gloeosporioides.

Here, we report for the first time on the mechanisms of action of the essential oil of Ruta graveolens (REO) against the plant pathogen Colletotrichum gloeosporioides. In particular, the presence of REO drastically affected the morphology of hyphae by inducing changes in the cytoplasmic membrane, such as depolarization and changes in the fatty acid profile where straight-chain fatty acids (SCFAs) increased by up to 92.1%. In addition, REO induced changes in fungal metabolism and triggered apoptosis-like responses to cell death, such as DNA fragmentation and the accumulation of reactive oxygen species (ROS). The production of essential enzymes involved in fungal metabolism, such as acid phosphatase, β-galactosidase, β-glucosidase, and N-acetyl-β-glucosaminidase, was significantly reduced in the presence of REO. In addition, C. gloeosporioides activated naphthol-As-BI phosphohydrolase as a mechanism of response to REO stress. The data obtained here have shown that the essential oil of Ruta graveolens has a strong antifungal effect on C. gloeosporioides. Therefore, it has the potential to be used as a surface disinfectant and as a viable replacement for fungicides commonly used to treat anthracnose in the postharvest testing phase.

Exploring the defense strategies of benzalkonium chloride exposures on the antioxidant system, photosynthesis and ROS accumulation in Lemna minor

With the advent of technological advancements post the industrial revolution, thousands of chemicals are introduced into the market annually to enhance different facets of human life. Among these, pharmaceutical and personal care products (PPCPs), including antibiotics and disinfectants, such as benzalkonium chlorides (BACs), are prominent. BACs, often used for surface and hand disinfection in high concentrations or as preservatives in health products such as nasal sprays and eye drops, may present environmental risks if they seep into irrigation water through prolonged exposure or improper application. The primary objective of this study is to elucidate the tolerance mechanisms that may arise in Lemna minor plants, known for their remarkable capability to accumulate substances efficiently, in response to exogenously applied BACs at varying concentrations. The study applied six different concentrations of BACs, ranging from 0.25 to 10 mg L−1. The experimental period spanned seven days, during which the treatments were conducted in triplicate to ensure reliability and reproducibility of the results. It was observed that low concentrations of BACs (0.25, 0.5 and 1 mg L−1) did not elicit any statistically significant changes in growth parameters. However, higher concentrations of BACs (2.5, 5, and 10 mg L−1) resulted in a reduction in RGR by 20%, 28%, and 36%, respectively. Chlorophyll fluorescence declined significantly at BAC doses of 5 and 10 mg L−1, with Fv/Fm ratios decreasing by 9% and 15%, and Fv/Fo ratios by 40% and 39%, respectively. Proline content decreased in all treatment groups, with a 46% reduction at 10 mg L−1 BAC. TBARS and H2O2 contents increased proportionally with BAC dosage, showing the highest increases of 30% and 40% at 10 mg L−1, respectively. The noticeable increase in SOD enzyme activity at BAC concentrations of 0.5, 1, and 2.5 mg L−1, with increases of 2.7-fold, 2.2-fold, and 1.7-fold respectively, along with minimal accumulation of H2O2, suggests that L. minor plants have a strong tolerance to BAC. This is supported by the efficient functioning of the CAT and GST enzymes, especially evident at the same concentrations, where increased activities effectively reduce the buildup of H2O2. In the AsA-GSH cycle, although variations were observed between groups, the contribution of the GR enzyme to the preservation of GSH content by recycling GSSG likely maintained redox homeostasis in the plant, especially at low concentrations of BACs. The study revealed that L. minor effectively accumulates BAC alongside its tolerance mechanisms and high antioxidant activity. These results underscore the potential for environmental cleanup efforts through phytoremediation.

Comparative multivariate analysis for high-touch surface disinfection using optimized ultraviolet-C LEDs configuration

UV light-emitting diodes (LEDs) have been regarded as feasible alternatives for traditional UV lamps since the early 2000s, owing to their improved safety features, environmental advantages, and efficiency. Because of the inherent challenges associated with lower intensity of LEDs over extended distances, our findings demonstrated the optimized disinfection efficiency using various LED setups. This study evaluated the antimicrobial effectiveness of single, six, and eight-LED configurations against Staphylococcus aureus (S. aureus), specifically emphasizing attaining the utmost disinfection efficiency within an extended range of up to 60 cm. With an 8-LED configuration, the study achieved a substantial reduction of 6.10×104 CFU/mL from an initial level of 5.20×109 CFU/mL, corresponding to 4.9-log10 inactivation, requiring a dose of 264 µJ-cm−2. 2.9-log10 inactivation was achieved using a 6-LED, yielding lower yet comparable efficiency requiring 192 µJ-cm−2 of dose. However, with 60 µJ-cm−2 of dose, a single LED could only reduce the bacterial burden from the initial level to merely 0.2-log10 inactivation, corresponding to 2.9 × 109 CFU/mL, under similar exposure settings. In conclusion, UV-LEDs show promise for disinfection, with LED configuration and distance significantly impacting their efficiency, holding perspective for various applications, particularly within healthcare facilities.

Ứng dụng tiêm Botulinum Neurotoxin dưới hướng dẫn của siêu âm và điện cơ trong điều trị loạn trương lực cơ cổ: Ca lâm sàng

Dystonia is a movement disorder characterized by persistent or intermittent muscle contractions, involuntary, creating repetitive and/or abnormal postures and movements. Dystonic movements result in characteristic twisting or tremor patterns. Dystonia often begins or worsens with intentional movements, combined with excessive muscle activation. Dystonia is classified according to the affected body regions: focal dystonia, segmental dystonia, multifocal dystonia, hemidystonia, and generalized dystonia. Anterocollis is a type of cervical dystonia, caused by persistent, repetitive contractions of neck muscle groups, leading to excessive neck flexion. Anterocollis is described in the context of movement disorders in Parkinson’s syndrome (Parkinson’s disease, multiple system atrophy, etc.). Treatment of dystonia is primarily symptomatic: medications, Botulinum Neurotoxin (BoNT) injections, surgery, and physical therapy. Among these, BoNT injections are considered the first choice for focal or segmental dystonia.Botulinum Neurotoxin acts at the neuromuscular junction, leading to muscle paralysis. BoNT injections require injection equipment, surface disinfection, and determination of the injection site based on clinical landmarks. Some deep and difficult injections require specialized techniques such as electromyography (EMG) and ultrasound. In the case of anterocollis, BoNT is often applied to both superficial and deep muscles. To achieve effectiveness and limit complications during and after injection, practitioners often use combined EMG and ultrasound techniques. We present a clinical case to illustrate the value of using BoNT injections under the simultaneous guidance of EMG and ultrasound in treating anterocollis at the Neurology Department of Hanoi Medical University Hospital.

Evaluating the Effectiveness of Two Disinfection Processes on Bacteria Causing Nosocomial Infections in the Intensive Care Units of an Educational, Research, and Treatment Hospital in Semnan, Iran

Background: Disinfection is the process of killing pathogenic microorganisms on non-living surfaces. Selecting and using appropriate and standard disinfection methods can significantly reduce nosocomial infections. Objectives: This study aimed to determine the effectiveness of the disinfection process on bacteria causing nosocomial infections in an educational, research, and treatment hospital located in Semnan, Iran in 2021. Methods: In 2021, 156 samples were collected and analyzed for microorganism growth in a suitable culture medium from the surgical ICU, CCU, and internal wards of men at Kosar Hospital in Semnan. Samples were taken during three work shifts (morning, evening, and night) from breakfast tables, suction devices, ventilators or biopsy equipment, and rods at the patient's bed. Results: Before the disinfection process, 81.8% (27 cases) of the samples tested positive for various microorganisms. The most commonly grown microorganisms were Klebsiella (33.3%) and Staphylococcus (18.2%). The highest percentage of microorganisms developed after disinfection with Sayasept and sodium hypochlorite were seen at two and a half hours (26.3%) and two hours (26.7%), respectively. Disinfection with sodium hypochlorite significantly reduced the number of microorganisms grown in the post-disinfection period compared to before (P-value = 0.042), whereas disinfection with Sayasept did not show a statistically significant effect (P-value = 0.132). Conclusions: Using sodium hypochlorite greatly decreased the number of microorganisms in the post-disinfection period, despite the high number of microorganisms present before disinfection in the analyzed wards. It is vital to implement hygienic policies that ensure proper disinfection of hospital surfaces and provide adequate training, particularly emphasizing the use of sodium hypochlorite.

The effect of bending angle on a flexible electrode DBD plasma under sinusoidal excitation

There is a critical demand for sophisticated surface disinfection and sterilization devices accessible to the public by using cold atmospheric pressure air plasmas. A flexible printed circuit design of a dielectric barrier discharge reactor under non-bending and two bending configurations with an angle of 120° and 180° was studied. The characteristics of power consumption, the optical emission spectrum, dynamic process, electrode temperature and ozone concentration are evaluated. The non-bending configuration produces more O3, as compared to the bending configuration at the same applied voltage. The 180° configuration has a maximum concentration of excited species at the expense of higher electrode temperature. Both bending configurations demonstrated the propagation of filaments to bending axis where the continues luminescence is observed due to the high electrical field. The energy efficiency for plasma-generated reactive species reaches to 40% for non-bending configuration and decreases with the increase of bending angle. This research provides a new strategy for perspective into the plasma generated reactive species in biomedical and environmental applications.

Topographic analysis of fiber posts after surface disinfection with different methods

Aims: This study aims to comprehensively examine the surface morphology of fiber posts after undergoing various disinfection methods, utilizing scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Materials and Methods: Twenty-one fiber posts were randomly allocated into seven experimental groups, each consisting of three samples. The disinfection methods employed were as follows: GC - no disinfection treatment; GAL - immersion in 70% alcohol, following the manufacturer's recommended protocol; GHP - soaking in 2.5% sodium hypochlorite for a duration of 10 minutes; GCL - soaking in 2% chlorhexidine gluconate for a period of five minutes; GAC - 30-second etching with 35% phosphoric acid; GPH - soaking in 10% hydrogen peroxide for a duration of 20 minutes; and GSL - autoclave sterilization. Following the disinfection procedures, SEM was employed to scrutinize the surface topography of the posts, while EDX was utilized to identify the chemical elements present on the sample surfaces. Subsequently, a descriptive analysis was conducted on the SEM images and EDX data. Results: SEM analysis revealed that all groups exhibited regions with epoxy resin-coated fibers alongside sections with exposed glass fibers. Analysis of the EDX data indicated that there were no significant differences in the predominant chemical elements across the groups. Carbon (C) and oxygen (O) registered the highest peaks, followed by silicon (Si), zirconium (Zr), sodium (Na), aluminum (Al), and calcium (Ca). Conclusions: The disinfection methods under investigation did not induce substantial alterations in the surface morphology of the fiber posts.

Does Patient Perception of Cleanliness Still Matter? The Relationship between HCAHPS and HAC During the COVID-19 Pandemic

Background: Environmental contamination of surfaces is known to be one of the most common causes of healthcare associated infections (HAIs), with cleaning and disinfection of surfaces shown to reduce the incidence of HAIs and contribute to overall hospital cleanliness. Prior research showed that there was a relationship between a hospital’s performance on the Hospital Consumer Assessment of Healthcare Providers and Systems survey question on patient perception of cleanliness and their HAC score. However, this research was done prior to the COVID-19 pandemic. This study looked to examine if the pandemic changed the relationship between patient perception of cleanliness and HAC score performance. Method: A retrospective correlational study was performed to examine if the relationship between patient perception of cleanliness and the incidence of Clostridioides difficile (CDI) and Methicillin-Resistant Staphylococcus aureus (MRSA) HAIs, as defined by the facility’s HAC score, were affected by the COVID-19 pandemic. Multiple Center for Medicare and Medicaid Services (CMS) datasets were utilized for the study. There were approximately 2700 acute care facilities that reported data on the HCAHPS perception of cleanliness question and either a MRSA or CDI HAC score for the period of January 1, 2021, to December 31st, 2021. Basic descriptive statistics and Spearman’s rho correlation analyses were performed to examine the potential associations between the two scores. Result: For MRSA, the study found that as the percentage of patients who reported that their room was “always” clean increased, the hospital’s HAC score decreased (r= −0.141, p = < 0.001). Additionally, as the percentage of patients who reported their room was “never” clean increased, the hospital’s HAC score increased (r= 0.175, p = <0.001) For C. difficile, the analysis also revealed that as the percentage of patients who reported their room was “always” clean increased, there was not a significant change in the hospital’s HAC score (r= −0.023, p = 0.237). There was also not a significant change in the HAC score when the percentage of patients who reported their room as “never” clean increased (r= −0.012, p = 0.527).Conclusion: The study found that for MRSA, a hospital’s performance on the HCAHPS performance on patient perception of cleanliness is related to their performance on their HAC score. This did not hold true when looking at C. difficile infections, which is in contrast to the prior evidence. Further research is needed to determine if there are specific factors that may have influenced this change.Disclosure: Caitlin Crews-Stowe: Employee- ActivePure Medical

Low-cost, local production of a safe and effective disinfectant for resource-constrained communities.

Improved hygiene depends on the accessibility and availability of effective disinfectant solutions. These disinfectant solutions are unavailable to many communities worldwide due to resource limitations, among other constraints. Safe and effective chlorine-based disinfectants can be produced via simple electrolysis of salt water, providing a low-cost and reliable option for on-site, local production of disinfectant solutions to improve sanitation and hygiene. This study reports on a system (herein called "Electro-Clean") that can produce concentrated solutions of hypochlorous acid (HOCl) using readily available, low-cost materials. With just table salt, water, graphite welding rods, and a DC power supply, the Electro-Clean system can safely produce HOCl solutions (~1.5 liters) of up to 0.1% free chlorine (i.e.,1000 ppm) in less than two hours at low potential (5 V DC) and modest current (~5 A). Rigorous testing of free chlorine production and durability of the Electro-Clean system components, described here, has been verified to work in multiple locations around the world, including microbiological tests conducted in India and Mexico to confirm the biocidal efficacy of the Electro-Clean solution as a surface disinfectant. Cost estimates are provided for making HOCl locally with this method in the USA, India, and Mexico. Findings indicate that Electro-Clean is an affordable alternative to off-the-shelf commercial chlorinator systems in terms of first costs (or capital costs), and cost-competitive relative to the unit cost of the disinfectant produced. By minimizing dependence on supply chains and allowing for local production, the Electro-Clean system has the potential to improve public health by addressing the need for disinfectant solutions in resource-constrained communities.

Inactivation of yellow fever virus by WHO-recommended hand rub formulations and surface disinfectants.

Despite continued outbreaks of yellow fever virus (YFV) in endemic regions, data on its environmental stability or guidelines for its effective inactivation is limited. Here, we evaluated the susceptibility of the YFV 17D vaccine strain to inactivation by ethanol, 2-propanol, World Health Organization (WHO)-recommended hand rub formulations I and II, as well as surface disinfectants. In addition, two pathogenic strains were tested to compare inactivation kinetics by WHO-recommended hand rub formulations I and II. Furthermore, environmental stability of the vaccine strain was assessed. YFV 17D particles displayed infectivity half-life decay profiles of ~13 days at room temperature. Despite this extended environmental stability, YFV was efficiently inactivated by alcohols, WHO-recommended hand formulations, and four out of five tested surface disinfectants. These results are useful in defining disinfection protocols to prevent non-vector borne YFV transmission.

Ramularia mali associated with symptoms of dry lenticel rot, an emerging postharvest disease on apples in Italy.

Ramularia mali Videira & Crous is an emerging postharvest pathogen on apple (Malus × domestica Borkh.) in Italy and other apple producing countries (Prencipe et al. 2023). After 3 to 6 months of cold storage at 1 - 2 °C and low oxygen levels of 0.5 - 2 %, lenticels show black-brown speckled dry rot of 1 mm - 5 mm in diameter, without colonizing underlying tissue. The most affected cultivar (cv.) in South Tyrol (northern Italy) is Golden Delicious and postharvest losses due to characteristic lenticel spots range from 10 % to above 50 %. Four symptomatic fruits, originating from two orchards (Latsch/Laces and Bozen/Bolzano; South Tyrol, Italy), respectively, were sampled after cold storage (= ultra-low oxygen; 0.5 % O2 and 1 °C). After surface disinfection with 70 % EtOH for 1 min, sixteen explants from lenticel spots were cultivated on potato dextrose agar (PDA) at 25 °C. Two isolates, morphologically identified as Ramularia sp., were sequenced and showed high identities to R. mali type culture CBS 129581: 100 % and 99.31 % identity for ITS region (MH865432); 94.66 % and 91.41 % for TEF-1α (KJ504693); 97.22% and 97.40% for RpbII (KJ504649). Isolates were cultivated at 25 °C for 2 weeks and conidia were harvested with 3.0 mL 0.05 % Tween®20. Inoculation was performed in triplicate on 5-month cold stored fruits cv. Golden Delicious. After surface disinfection for 1 min with cotton swabs, which were immersed in 70 % EtOH, 10 µL spore suspension of each isolate (8.50 × 107 spores mL-1 in 0.05 % Tween®20) were injected horizontally beneath the epidermis with a syringe (Hamilton® model 710N). Also, a mixture of both isolates was used. Controls were carried out with 0.05 % Tween®20 only. Apples were stored either at 9 °C in the dark or at 1°C and 0.5 % oxygen for 4 months. First symptoms were observed for both spore concentrations after 2 weeks at 9 °C. The injection pathway changed to a brownish color, whereas the control did not show any change (Fig. 1). Final evaluation was carried out after 4 months, but the fruits did not show further symptom development. Fruits stored at 1°C for 5 months were simultaneously evaluated, confirming that the pathogen invaded the tissue surrounding the injection site, without penetrating deeper into the fruit flesh. (Fig. 2). Reisolation from artificially infected apples was successfully achieved, and sequence analysis was performed on the DNA extracts from the obtained isolates. Concatenated sequences of ITS (deposited to GenBank under the accession numbers: PP439643 -PP439647), TEF-1α (PP480231-PP480235), and RbpII (PP480226-PP480230) were subjected to multi-locus sequence analysis. References sequences of R. nyssicola CBS 127665, R. collo-cygni CBS 101181, R. vizellae CBS 115981, R. eucalypti CBS 120726, R. hydrangeae-macrophyllae CBS 122272, R. glennii CBS 129441 and R. mali CBS 129581 included and aligned by the CLUSTALW algorithm within the software Geneious® 11.1.5 (Biomatters Inc., New Zealand). Phylogeny was reconstructed with MEGAX (Version 10.2.6) (Kumar et al. 2018) based on the Maximum Likelihood (ML) algorithm (Fig. 3). Isolates from artificially infected fruit clustered with the R. mali type culture. Although Gianetti et al. (2012) and Lindner (2013), respectively, first described Ramularia sp. as a postharvest pathogen on apple, the present study demonstrated the reproduction of lenticel dry rot symptoms by R. mali.