Activity Of Disinfectants Research Articles

Case-area targeted interventions during a large-scale cholera epidemic: A prospective cohort study in Northeast Nigeria.

Cholera outbreaks are on the rise globally, with conflict-affected settings particularly at risk. Case-area targeted interventions (CATIs), a strategy whereby teams provide a package of interventions to case and neighboring households within a predefined "ring," are increasingly employed in cholera responses. However, evidence on their ability to attenuate incidence is limited. We conducted a prospective observational cohort study in 3 conflict-affected states in Nigeria in 2021. Enumerators within rapid response teams observed CATI implementation during a cholera outbreak and collected data on household demographics; existing water, sanitation, and hygiene (WASH) infrastructure; and CATI interventions. Descriptive statistics showed that CATIs were delivered to 46,864 case and neighbor households, with 80.0% of cases and 33.5% of neighbors receiving all intended supplies and activities, in a context with operational challenges of population density, supply stock outs, and security constraints. We then applied prospective Poisson space-time scan statistics (STSS) across 3 models for each state: (1) an unadjusted model with case and population data; (2) an environmentally adjusted model adjusting for distance to cholera treatment centers and existing WASH infrastructure (improved water source, improved latrine, and handwashing station); and (3) a fully adjusted model adjusting for environmental and CATI variables (supply of Aquatabs and soap, hygiene promotion, bedding and latrine disinfection activities, ring coverage, and response timeliness). We ran the STSS each day of our study period to evaluate the space-time dynamics of the cholera outbreaks. Compared to the unadjusted model, significant cholera clustering was attenuated in the environmentally adjusted model (from 572 to 18 clusters) but there was still risk of cholera transmission. Two states still yielded significant clusters (range 8-10 total clusters, relative risk of 2.2-5.5, 16.6-19.9 day duration, including 11.1-56.8 cholera cases). Cholera clustering was completely attenuated in the fully adjusted model, with no significant anomalous clusters across time and space. Associated measures including quantity, relative risk, significance, likelihood of recurrence, size, and duration of clusters reinforced the results. Key limitations include selection bias, remote data monitoring, and the lack of a control group. CATIs were associated with significant reductions in cholera clustering in Northeast Nigeria despite operational challenges. Our results provide a strong justification for rapid implementation and scale-up CATIs in cholera-response, particularly in conflict settings where WASH access is often limited.

Impact of artificial accelerated ageing of PVC surfaces and surface degradation on disinfectant efficacy

Standardised efficacy surface tests for disinfectants are performed on pristine surfaces. There is a growing interest in understanding the impact of surface ageing on disinfectant activity, owing for example to the increased usage of UV radiation and oxidative chemistries for surface decontamination. This acknowledges that general surface "wear and tear" following UV radiation and oxidative biocide exposure may impact biocidal product efficacy. PVC surfaces were aged through thermal and UV-A radiation (340nm wavelength) following the use of standard ageing surface protocols to simulate natural surface degradation. Surface roughness, contact angle and scanning electron microscopy were performed to evaluate physical changes in PVC surfaces before and after artificial ageing. The efficacy of five pre-impregnated disinfectant wipes were evaluated using the ASTM E2967-15 on stainless steel (control) and PVC surfaces (aged and non-aged). The type of formulation and the organism tested remained the most significant factors impacting disinfectant efficacy, compared to surface type. Both thermal ageing and UV-A exposure of PVC surfaces, clearly showed signs of surface degradation, notably an increase in surface roughness. Physical changes were observed in the roughness of PVC after artificial ageing. A difference in disinfectant efficacy dependent on aged PVC surfaces was observed for some, but not all formulations. We showed that surface type and surface ageing can affect biocidal product efficacy, although in a non-predictable manner. More research is needed in this field to ascertain whether surface types and aged surfaces should be used in standardized efficacy testing.

Strategic implementation of upflow microbubble airlift photocatalytic process to control heavy metal resistant-MDR bacteria and the associated genes in wastewater

The emergence of multidrug resistance (MDR) and heavy metal resistance (HMR) in bacterial pathogens and genes through mobile genetic elements (MGEs) from wastewater effluents needs to be eradicated using green technology. HMR is critical to controlling antimicrobial resistance but has been neglected in most photocatalytic disinfection (PCD) studies. Advanced photocatalysis in antimicrobial studies requires a strategic approach to enhance the disinfection efficiency. This study applied an optimized upflow airlift photocatalytic reactor (UAPR) with microbubble air and blue light to remove the antimicrobial resistance (HMR–MDR bacteria (HMR–MDRB), HMR genes (HMRGs), antibiotic resistant genes (ARGs) and MGEs) and inhibit pathogenicity in a mixed culture of high-strength HMR–MDRB isolated from wastewater. Stable dissolved oxygen (DO) supplementation and blue light significantly affected the HMRGs and MGE reduction, resulting in enhanced disinfection activity (30 %) and reaction time (60 min) required for the complete inactivation of HMR-MDRB mixed culture. The process effectively reduced the blaNDM-1 (3.37 log), pbrT (2.18 log), intl1 (2.16 log), and tn916/1545 (4.07 log), with a PCD rate constant (kg) of 0.0515 min−1, 0.0359 min−1, 0.0292 min−1, and 0.0662 min−1, respectively. Process mechanism studies showed that the stable supplementation of DO was a critical factor in controlling the type of reactive oxygen species (ROS), resulting in type II ROS, 1O2, as the critical free radical contributing to the reduction of ARGs and integron, whereas h+ was the ROS for pbrT and transposon.

Green graphene supported Cu2O-Ag2O S-scheme photocatalyst with high disinfection activity for prevention of urinary tract infection in toilets: A metagenomic analysis

Amongst the universal infectious diseases, the urinary tract infection (UTI) is one of the most prevalent bacterial infections. Pathogenic microorganisms causing UTI mainly enter the human body from the unhygienic toilet environment. In this study, a graphene structured material (GSM) supported Cu2O-Ag2O composite was synthesized using the co-precipitation method and its photocatalysis-assisted disinfection performance against UTI-causing pathogens was assessed under LED irradiation. The metagenomic analysis of UTI-causing sites was performed by targeting the 16 S rRNA gene region using Illumina sequencing. The results showed that the common phylum identified in the toilets under study is Proteobacteria (76%) and the most dominating genera identified were Acinetobacteria (33%) and Pseudomonas (26%). 8 × 106 CFU mL−1 of Acinetobacter baumanii, Pseudomonas aeruginosa, and Escherichia coli were completely disinfected using the GSM-Cu2O-Ag2O composite within 30 min under LED irradiation. Enterococcus faecalis and mixed bacterial culture took 40 and 75 min, respectively, for complete inactivation. Holes are the major reactive species responsible for photocatalytic inactivation of bacteria. The structural changes of the cells were observed using scanning electron microscopy which indicates that photocatalytic disinfection caused drastic damage to the bacterial cell walls and it was further substantiated by the measurements of DNA and K+ leakage. The composite displayed complete inactivation, remarkable stability and acceptable reusability even after four consecutive cycles. The green composite, after degradation, is supposed to get sequestered in the natural environment without any persistence and bio-magnification prospects. Its potential use can usher in a new greener alternative to traditional toxic disinfectants like benzalkonium chlorides that can exert adverse impacts on the biological environment including human health.

Coaxial electrospun PVA-SAP functional nanofibers embedded with betel leaf extract for enhanced germicidal activity and breathability

This study investigates the formation of coaxial electrospun nanofibrous membrane with enhanced germicidal activity and breathability using superabsorbent polymer and polyvinyl alcohol integrated with betel leaf extract and its utilization for developing performance textiles. The functional nanofibrous membrane was fabricated through the coaxial electrospinning technique and characterized for the intended applications. The morphological investigation of the developed nano-membrane using scanning electron microscopy revealed the formation of regular nanofibers with diameters ranging from 154 to 200 nm. The FTIR spectra suggested the existence of functional compounds in the nanofibers from their characteristic peaks. The presence of the bioactive compounds in the ethanolic extract of betel leaf was explored using phytochemical screening. The analysis of antibacterial activity against S. aureus and E.coli using the agar disc diffusion method showed an enhanced zone of inhibition with a maximum dimension of 27 mm and 24 mm against S. aureus and E.coli, respectively. The developed coaxial nanofibrous membranes also demonstrated acceptable particle barrier performance with greater than 95 % efficiency and a superior tensile strength of 99.5 N. Besides, the improved moisture management and air permeability of coaxial nano-membranes embedded with betel leaf extracts suggested an easy transfer of fluid and moisture vapor from the body to the environment via the membrane. Hence, the improved germicidal activity with acceptable particle filtration efficiency and enhanced breathability of the developed coaxial electrospun nano-membranes indicated their potentiality of utilizing them in designing performance textiles with simultaneous barrier performance and breathability for comfort.

Infection prevention and control studies for care of patients with suspected or confirmed filovirus disease in healthcare settings, with focus on Ebola and Marburg: an integrative review

ObjectiveTo review evidence pertaining to methods for preventing healthcare-associated filovirus infections (including the survivability of filoviruses in clinical environments and the chlorine concentration required for effective disinfection), and to assess...

Nigella sativa Embedded Co-axial Electrospun PVA–Collagen Composite Nanofibrous Membrane for Biomedical Applications

Mitigating health issues utilizing medicinal plants is an ancient practice that has surged in recent times due to the advent of sophisticated technology. Plant extracts incorporated in electrospun nanofibers having biocompatibility and germicidal activity are, therefore, become a competitive choice for biomedical applications. In this study, a novel co-axial electrospun nanofibrous mat with enhanced antimicrobial performance was successfully developed using poly (vinyl alcohol) in the core and collagen– Nigella sativa in the sheath. The structural analysis of the developed nanofibrous mat through a scanning electron microscope revealed the formation of nanofibers with diameters varying from 205 to 250 nm randomly oriented in the membrane. The FT-IR spectroscopy confirmed the existence of poly(vinyl alcohol), collagen, and nigella extract in the nanofibrous mat from their respective characteristic peaks. The bactericidal assay against Gram-positive Staphylococcus aureus bacteria through the agar diffusion method demonstrated an improved antibacterial performance with a higher zone of inhibition (17 and 37 mm) of the coaxial electrospun nanofibers with the increased amount of nigella extract. The moisture management profile indicated an adequate interaction between nanofibers and moisture/liquid, transferring the fluids through the membrane satisfactorily. The formation of such electrospun nanofibers will pave the way for selecting electrospinning techniques for appropriate designing and fabricating nanofibrous materials with enhanced functional properties for biomedical applications.

Study of disinfectant activity against bee pathogenic enterobacteria in vitro

Dysbiosis is a pathological condition caused by violating the normal coexistence of bacterial organisms in one or more body systems. This disease arises due to the action of many ethological factors, the mechanisms of which arise from each other. Klebsiellosis of bee colonies is a relatively new disease of Apis mellifera, caused by pathogenic enterobacteria, which leads to the mass death of bees with signs of acute dyspepsia, particularly in the spring and autumn periods. To prevent klebsiellosis in bees, it is necessary to carry out veterinary and sanitary measures in apiaries every year, including disinfection. Modern beekeeping encourages the search for new antibacterial drugs to ensure the production technology of safe and high-quality beekeeping products suitable for sale. Preliminary laboratory assessment (in vitro) of the effectiveness of disinfectants against specific pathogens of specific diseases of bees will ensure an increase in the effectiveness of such agents in apiaries, which is economically effective for practical beekeeping. The purpose of the research was to determine the activity of different concentrations of the disinfectant (0.25 %, 0.5 %, 1.25 %, 2.5 %) with an active substance of an organic nature with covalent weakly polar bonds against pure cultures of pathogenic enterobacteria of bees of the species Klebsiella pneumoniae and Klebsiella (Enterobacter) aerogenes in vitro. The modified Kirby-Baur method on Mueller-Hinton agar was used for research. A bactericidal effect against a pure culture of Klebsiella pneumoniae species was registered after 24 hours with lysis zone diameters at 8.6 ± 0.27 mm (0.25 % concentration) – 15.0 ± 0.35 mm (2.5 % concentration). On the 3rd day of research, a bacteriostatic effect was registered with the largest diameter of the zone of growth retardation (24.4 ± 0.27 mm) at 2.5 % disinfectant concentration. Bactericidal and bacteriostatic effects were recorded on the culture of enterobacteria of bees of the species Klebsiella (Enterobacter) aerogenes for 24 hours of cultivation with zones of lysis – 6.8 ± 0.42 mm (0.25 %) – 11.8 ± 0.22 mm (2.5 %) and inhibition of bacterial growth at the level of – 21.8 ± 0.42 mm (0.25 %) – 25.8 ± 0.42 mm (2.5 %). At the same time, there was no significant difference between the zones of Klebsiella (Enterobacter) aerogenes growth retardation in concentrations of 0.5 % – 2.5 % on the 3rd day of research. The studied disinfectant has bactericidal and bacteriostatic effects on pure cultures of bee enterobacteria of the species Klebsiella pneumoniae and Klebsiella (Enterobacter) aerogenes in laboratory conditions, which is promising for further study of the drug.

Анализ закупок дезинфицирующих средств в медицинских организациях. Часть 2. 2020–2022?гг.

The COVID-19 pandemic had an impact on all spheres of public health. The multiplied load on medical organizations, forced use of unsuitable premises for treatment of people could not but affect disinfection activities. In addition, given the closed borders in 2020, there was a shortage of both raw materials and ready disinfectants on the market. On the one hand, this situation has led to an explosive interest of the business community in the disinfectants market. This is evidenced by the increased number of disinfectants registered in the Russian Federation from 164 in 2019 to 467 and 471 in 2020 and 2021, respectively. In this study, we analyzed technical specifications for the procurement of disinfectants by medical organizations posted on www.zakupki.gov.ru. Despite the fact that during the period there were relaxations in the procurement legislation that allowed medical organizations to directly purchase disinfectants from suppliers, the analysis revealed significant deviations in 2020 and 2021 in the consumption of disinfectants compared to 2017–2019 and 2022. For example, the consumption of disinfectants based on sodium hypochlorite increased significantly. Also, with the shortage and increased cost of alcohol-based skin antiseptics, purchases of soaps with antibacterial properties have increased, which is especially noticeable in 2021. However, the 2022 purchases indicate that healthcare organizations are returning to normal operations and their consumption of disinfectants is becoming similar to that seen in 2017–2019. Keywords: disinfectants, auctions, hospital-acquired infection.

Synthesis of 4-nitro-benzamides for evaluation antimicrobial and disinfectant activity: Part-I

4-nitro-benzamide derivatives have been synthesized and claimed in this research study. The compound VG1 and VG2 were synthesized by known methods. Ethylene diamine and isopropyl amine was dissolved in ethanolic 1 N NaOH separately and to it 4-nitro-benzoyl chloride was added. The products VG1 and VG2 were collected respectively.

Construction of a CuO/K-PCN p-n heterojunction with regulated band structure for enhanced visible Light-Driven Photocatalytic-Fenton disinfection activity

The photocatalytic heterogeneous Fenton process has garnered significant attention from researchers. This study successfully synthesized composited CuO nanoparticles with K-doping graphitic carbon nitride (K-PCN). The combination of CuO and K-PCN formed a p-n heterojunction, generating an internal electric field at the contact interface. By regulating the energy band position of PCN through K-doping, the thermodynamic transfer trend of photogenerated electrons became consistent with the electric field trend, leading to enhanced migration of electrons. Consequently, the photocatalytic and Fenton reactions exhibited better synergy, resulting in higher production of hydroxyl radicals and improved bactericidal performance. Under visible light irradiation, the CuO/K-PCN system demonstrated great bactericidal performance, achieving increased inactivation efficiency, from 2.8-log to 7-log in 25 min. The catalysts were characterized using SEM, TEM, XPS, FT-IR, XRD, and EPR techniques. Also, CuO/K-PCN displayed a broader wavelength range of light response. And, an efficient small-scale flow reactor further displayed the practical application potential of the CuO/K-PCN-based system. This research offers a straightforward and efficient method for thorough water disinfection using solar energy.

Near-infrared-guided NO generator for combined NO/photothermal/chemodynamic therapy of bacterial infections

Nitric oxide (NO)-based gas therapy approaches are promising in the treatment of infections; however, these strategies are hindered by poor delivery to the target site, which leads to unsatisfactory effects. In this study, we developed a NO-controlled platform (SCM@HA) via NO-generating mesoporous silica nanoparticles co-doped with sodium nitroprusside and copper sulphide to control NO production under near-infrared (NIR)-laser irradiation. Irradiation with an 808 nm NIR laser rapidly triggered the release of NO from the particles to actualise gas therapy. Photothermal therapy (PTT) also increased the local microenvironment temperature, and the close relationship between chemodynamic therapy (CDT) and temperature suggests that the increasing temperature facilitates in its working. The hydroxyl radicals generated by CDT can destroy the structure of bacteria in acidic environments. The germicidal activity of the nanoparticles was determined by the combined action of PTT, CDT, and NO-based gas therapy. The nanoparticles showed bactericidal activity in vitro against bacterial strains Staphylococcus aureus (S. aureus) and Salmonella typhimurium (S. typhimurium). Finally, the anti-infective efficacy in vivo in S. aureus-infected mouse model was demonstrated. Thus, the synergistic antimicrobial effects of NO-generating silica nanoparticles have good potential for the non-antibiotic treatment of bacterial infections in wounds. Statement of significanceBacterial infections and resistance are challenging health threats. Therefore, the development of an antibiotic-independent method is essential for the treatment of wound bacterial infections. In this study, NO-generating nanoparticles loaded with sodium nitroprusside in copper sulphide-doped mesoporous silica were prepared to control the long-term release of NO using near-infrared laser, which has good efficacy of PTT and CDT. The bactericidal effects of as-prepared nanoparticles against S. aureus and S. typhimurium have been well elucidated. This study proposes a feasible method in the field of NO-based therapy, thus paving the way that will benefit for the treatment of bacterial infections in wounds.

Evaluating the Bactericidal Activity of Various Disinfectants against Pseudomonas aeruginosa Contamination in Broiler Chicken Hatcheries

Evaluating the Bactericidal Activity of Various Disinfectants against Pseudomonas aeruginosa Contamination in Broiler Chicken Hatcheries

A comprehensive literature scoping review of infection prevention and control methods for viral-mediated gene therapies.

This comprehensive literature scoping review outlines available infection prevention and control (IPC) methods for viral-mediated gene therapies and provides one IPC strategy for the healthcare setting based on a single-center recommendation. A team of experts in pharmacy, healthcare epidemiology, and biosafety with experience in viral-mediated gene therapy was assembled within a pediatric hospital to conduct a comprehensive literature scoping review. The comprehensive review included abstracts and full-text articles published since 2009 and utilized prespecified search terms of the five viral vectors of interest: adenovirus (AV), retrovirus (RV), adeno-associated virus (AAV), lentivirus (LV), and herpes simplex virus (HSV). Case reports, randomized controlled trials, and bench research studies were all included, while systematic reviews were excluded. A total of 4473 case reports, randomized control trials, and benchtop research studies were identified using the defined search criteria. Chlorine compounds were found to inactivate AAV and AV, while alcohol-based disinfectants were ineffective. There was a relative paucity of studies investigating surface-based disinfection for HSV, however, alcohol-based disinfectants were effective in one study. Ultraviolent irradiation was also found to inactivate HSV in numerous studies. No studies investigated disinfection for LV and RV vectors. The need to define IPC methods is high due to the rapid emergence of viral-mediated gene therapies to treat rare diseases, but published clinical guidance remains scarce. In the absence of these data, our center recommends a 1:10 sodium hypochlorite solution in clinical and academic environments to ensure complete germicidal activity of viral-mediated gene therapies.

ИЗУЧЕНИЕ ДЕЗИНФЕКЦИОННОЙ ЭФФЕКТИВНОСТИ НОВОГО СРЕДСТВА НА ОСНОВЕ ТРЕТИЧНЫХ АМИНОВ ПО ОТНОШЕНИЮ К ГРАМПОЛОЖИТЕЛЬНЫМ И ГРАМОТРИЦАТЕЛЬНЫМ МИКРООРГАНИЗМАМ В ЛАБОРАТОРНЫХ УСЛОВИЯХ

It was established that a sample of the disinfectant «STEROX vet» showed disinfection activity against gram-positive and gram-negative microorganisms. Disinfection of rough (wood, concrete) test surfaces artificially contaminated with E. coli str. 1257 occurred at a concentration of 1,5% and exposure of 3 hours, S. aureus str. ATCC 6538-P FDA 209-P – at 2% and exposure of 3 hours, at a consumption rate of 0,5 l/m2, Mycobacterium str. B-5 – at a concentration of 5%, double irrigation with an exposure of 24 hours at a consumption rate of 0,5 l/m2 for each application.

Chemical characterization of sunflower oil oxidized by UV and ozone with different degrees of oxidation and study of their antimicrobial action

Oxidation by the action of ozone takes place at high rates and involves the reaction of ozone molecules with fatty acid double bonds followed by the formation of stable oxidation products with biological activity. In the present work, a comparative study on sunflower oil oxidized by ultraviolet (UV) light and ozone was carried out. This study involved the chemical characterization of sunflower oil oxidized by UV irradiation and ozonation, in addition to assessing the germicidal activity of oxidized oils obtained under various conditions. The results indicated that under the conditions studied, the increase in the dose of UV irradiation did not produce significant changes in the level of oxidation of the oil. Ozonation promoted the formation of oxygenated compounds at higher rates, increasing in concentration as the applied dosage of ozone increased. The germicidal activity of the oils behaved similarly, with considerably higher activity found in the ozonized oils.

The influence of the experimental composition of disinfection preparations based on polyhexamethyleneguanidine and nanoaquachelates of metals on test cultures of microorganisms

When developing a new and effective disinfectant, the existing microbial composition and the ability of microorganisms to form biofilms should be considered. Bacteria in the environment on various surfaces exist in two forms: in the form of planktonic cultures and the form of a formed microbial biofilm. Microorganisms in biofilm are more resistant to factors existing in nature and to the action of various antibacterial compounds. Therefore, when developing disinfectants, it is essential to study the bactericidal effect of newly created agents on bacteria that have formed biofilms. The purpose of the work was to investigate the effect of an experimental composition of a disinfectant based on polyhexamethyleneguanidine (PHMG) and nanoaquachelates of metals on the biofilm-forming properties of microorganisms and to determine the antimicrobial effect of the agent applied to test materials (stainless and galvanized steel, wood, tile). Microbiological studies on the determination of the bactericidal effect of experimental variants of the disinfectant with PHMG and nanoaquachelates of metals were carried out following generally accepted methods. Research on the effect of different disinfectant concentrations on microorganisms in biofilms was carried out according to the methodological recommendations “Determining the bactericidal activity of disinfectants on bacteria in biofilms”. All studies were carried out in triplicate, and the obtained data were subjected to statistical processing. The use of a 2 % solution of the developed disinfectant based on nanoaquachelates of metals and PHMG with an exposure of 40 minutes provides an entirely bactericidal effect on the test cultures of S. aureus, E. coli, and C. albicans in the biofilm. When studying the bactericidal activity of the research composition of the developed disinfectant against museum strains of microorganisms applied to the test materials, it was established that: when using the museum strain of S. aureus applied to galvanized and stainless steel to ensure the bactericidal effect, a concentration of 0.0625 % and 0.0312 % is required for exposures of 20 and 40 minutes. When using wooden and tiled surfaces, a higher concentration of disinfectant is needed, namely 0.125 % and 0.0625 %, for exposures of 20 and 40 minutes; for contamination by the museum strain of E. coli of galvanized and stainless steel, the bactericidal effect was observed at a concentration of 0.0312 % for both 20 min and 40 min. To achieve the bactericidal effect of the agent on a wooden surface within 20 minutes of action, the required concentration of the agent was at least 0.125 %, and after exposure for 40 minutes – 0.0625 %. The bactericidal effect on the tile surface was provided at concentrations of 0.0625 % and 0.0312 % for 20 and 40 min of exposure, respectively; when using the museum strain of C. albicans applied to metal surfaces, the bactericidal effect was observed at disinfectant concentrations of 0.0625 % and 0.0312 % and exposure for 20 and 40 minutes. The tiled surface was disinfected from C. albicans at a composition concentration of 0.0625 % within 20 minutes of exposure, and a wooden surface was disinfected at a composition concentration of 0.125 %.

Стратегия развития подготовки кадров в области медико-профилактического дела в Санкт-Петербурге на современном этапе

The development of the training system in the field of medical and preventive affairs in St. Petersburg was analyzed. The main tasks of staffing organizations and health care institutions, including the disinfection profile, are noted, which require immediate solution Keywords: licensing of disinfection activities, sanitary and epidemiological service, organizations and institutions of disinfection profile, medical organizations, secondary vocational education in the specialty «medical and preventive business».

Ultraviolet-C light at 222 nm has a high disinfecting spectrum in environments contaminated by infectious pathogens, including SARS-CoV-2.

Ultraviolet light (UV) acts as a powerful disinfectant and can prevent contamination of personal hygiene from various contaminated environments. The 222-nm wavelength of UV-C has a highly effective sterilization activity and is safer than 275-nm UV-C. We investigated the irradiation efficacy of 222-nm UV-C against contaminating bacteria and viruses in liquid and fabric environments. We conducted colony-forming unit assays to determine the number of viable cells and a 50% tissue culture infectious dose assay to evaluate the virus titration. A minimum dose of 27 mJ/cm2 of 222-nm UV-C was required for >95% germicidal activity for gram-negative and -positive bacteria. A 25.1 mJ/cm2 dose could ensure >95% virucidal activity against low-pathogenic avian influenza virus and severe acute respiratory syndrome coronavirus (SARS-CoV-2). In addition, this energy dose of 222-nm UV-C effectively inactivated SARS-CoV-2 variants, Delta and Omicron. These results provide valuable information on the disinfection efficiency of 222-nm UV-C in bacterial and virus-contaminated environments and can also develop into a powerful tool for individual hygiene.

Stability of the Virucidal Activity of Commercial Disinfectants against Avian Influenza Viruses under Different Environmental Conditions.

Highly pathogenic avian influenza viruses (HPAIVs) have caused outbreaks in both domestic and wild birds during the winter seasons in several countries in the Northern Hemisphere, most likely because virus-infected wild ducks overwinter and serve as the primary source of infection for other birds in these countries. Several chemical disinfectants are available to deactivate these viruses outside a living organism. However, their virucidal activity is known to be compromised by various factors, including temperature and contamination with organic matter. Hence, the effectiveness of virucidal activity under winter field conditions is crucial for managing HPAIV outbreaks. To investigate the impact of the winter field conditions on the virucidal activity of disinfectants against AIVs, we assessed the stability of the virucidal activity of seven representative disinfectants that are commercially available for poultry farms in Japan against both LPAIVs and HPAIVs under cold and/or organic contamination conditions. Of the seven disinfectants examined, the ortho-dichlorobenzene/cresol-based disinfectant exhibited the most consistent virucidal activity under winter field conditions, regardless of the virus pathogenicity or subtype tested.