Surfaces In Healthcare Settings Research Articles

A critical assessment of microbial-based antimicrobial sanitizing of inanimate surfaces in healthcare settings.

The global rise in antimicrobial resistance (AMR) poses a significant public health threat, especially in healthcare settings, where controlling the spread of antimicrobial genes is crucial. While person-to-person transmission remains the primary route for healthcare-associated infections (HAIs), hospital surfaces serve as key reservoirs for antimicrobial-resistant microorganisms. Regular cleaning and disinfection of these surfaces are essential. Microbial-based products for sanitizing hospital surfaces have emerged as promising tools to combat HAIs and AMR. However, a review of 32 publications found inconsistencies and potential risks. A total of 15 publications included hospital-based trials, while the rest were either in vitro or in situ assays, reviews, book chapters, or commentaries. In most of the hospital-based studies, specific strains of applied microorganisms were not identified, and the term "probiotic" was inaccurately used. These products mainly featured spores from Bacillus and Priestia genera, which was mainly hypothesized to work through competitive exclusion. Most hospital-based studies have shown that the application of microbial-based products resulted in a significant reduction in pathogens on surfaces, thereby contributing to a decrease in the incidence of healthcare-associated infections (HAIs). Further research is however needed to understand the effectiveness, mechanisms of action, and safety of microbial-based sanitizing agents. Strain-level identification is crucial for safety assessments, yet many reviewed products lacked this information. Consequently, there is a need for rigorous safety evaluations within existing regulatory frameworks to ensure the efficacy and safety of microbial-based cleaning products in healthcare settings.

Shifting from Ammonium to Phosphonium Salts: A Promising Strategy to Develop Next-Generation Weapons against Biofilms.

Since they are difficult and sometimes impossible to treat, infections sustained by multidrug-resistant (MDR) pathogens, emerging especially in nosocomial environments, are an increasing global public health concern, translating into high mortality and healthcare costs. In addition to having acquired intrinsic abilities to resist available antibiotic treatments, MDR bacteria can transmit genetic material encoding for resistance to non-mutated bacteria, thus strongly decreasing the number of available effective antibiotics. Moreover, several pathogens develop resistance by forming biofilms (BFs), a safe and antibiotic-resistant home for microorganisms. BFs are made of well-organized bacterial communities, encased and protected in a self-produced extracellular polymeric matrix, which impedes antibiotics' ability to reach bacteria, thus causing them to lose efficacy. By adhering to living or abiotic surfaces in healthcare settings, especially in intensive care units where immunocompromised older patients with several comorbidities are hospitalized BFs cause the onset of difficult-to-eradicate infections. In this context, recent studies have demonstrated that quaternary ammonium compounds (QACs), acting as membrane disruptors and initially with a low tendency to develop resistance, have demonstrated anti-BF potentialities. However, a paucity of innovation in this space has driven the emergence of QAC resistance. More recently, quaternary phosphonium salts (QPSs), including tri-phenyl alkyl phosphonium derivatives, achievable by easy one-step reactions and well known as intermediates of the Wittig reaction, have shown promising anti-BF effects in vitro. Here, after an overview of pathogen resistance, BFs, and QACs, we have reviewed the QPSs developed and assayed to this end, so far. Finally, the synthetic strategies used to prepare QPSs have also been provided and discussed to spur the synthesis of novel compounds of this class. We think that the extension of the knowledge about these materials by this review could be a successful approach to finding effective weapons for treating chronic infections and device-associated diseases sustained by BF-producing MDR bacteria.

Occupational inhalation exposure during surface disinfection—exposure assessment based on exposure models compared with measurement data

BackgroundFor healthcare workers, surface disinfections are daily routine tasks. An assessment of the inhalation exposure to hazardous substances, in this case the disinfectant´s active ingredients, is necessary to ensure workers safety. However, deciding which exposure model is best for exposure assessment remains difficult.ObjectiveThe aim of the study was to evaluate the applicability of different exposure models for disinfection of small surfaces in healthcare settings.MethodsMeasurements of the air concentration of active ingredients in disinfectants (ethanol, formaldehyde, glutaraldehyde, hydrogen peroxide, peroxyacetic acid) together with other exposure parameters were recorded in a test chamber. The measurements were performed using personal and stationary air sampling. In addition, exposure modelling was performed using three deterministic models (unsteady 1-zone, ConsExpo and 2-component) and one modifying-factor model (Stoffenmanager®). Their estimates were compared with the measured values using various methods to assess model quality (like accuracy and level of conservatism).ResultsThe deterministic models showed overestimation predominantly in the range of two- to fivefold relative to the measured data and high conservatism for all active ingredients of disinfectants with the exception of ethanol. With Stoffenmanager® an exposure distribution was estimated for ethanol, which was in good accordance with the measured data.Impact statementTo date, workplace exposure assessments often involve expensive and time consuming air measurements. Reliable exposure models can be used to assess occupational inhalation exposure to hazardous substances, in this case surface disinfectants. This study describes the applicability of three deterministic and one modifying-factor model for disinfection of small surfaces in healthcare settings, in direct comparison to measurements performed and will facilitate future exposure assessments at these workplaces.

One Step Forward with Dry Surface Biofilm (DSB) of Staphylococcus aureus: TMT-Based Quantitative Proteomic Analysis Reveals Proteomic Shifts between DSB and Hydrated Biofilm.

The Gram-positive bacterium Staphylococcus aureus is responsible for serious acute and chronic infections worldwide and is well-known for its biofilm formation ability. Recent findings of biofilms on dry hospital surfaces emphasise the failures in current cleaning practices and disinfection and the difficulty in removing these dry surface biofilms (DSBs). Many aspects of the formation of complex DSB biology on environmental surfaces in healthcare settings remains limited. In the present study, we aimed to determine how the protein component varied between DSBs and traditional hydrated biofilm. To do this, biofilms were grown in tryptic soy broth (TSB) on removable polycarbonate coupons in the CDC biofilm reactor over 12 days. Hydrated biofilm (50% TSB for 48 h, the media was then changed every 48 h with 20% TSB, at 37 °C with 130 rpm). DSB biofilm was produced in 5% TSB for 48 h at 35 °C followed by extended periods of dehydration (48, 66, 42 and 66 h at room temperature) interspersed with 6 h of 5% TSB at 35 °C. Then, we constructed a comprehensive reference map of 12-day DSB and 12-day hydrated biofilm associated proteins of S. aureus using a high-throughput tandem mass tag (TMT)-based mass spectrometry. Further pathway analysis of significantly differentially expressed identified proteins revealed that proteins significantly upregulated in 12-day DSB include PTS glucose transporter subunit IIBC (PtaA), UDP-N-acetylmuramate-L-alanine ligase (MurC) and UDP-N-acetylenolpyruvoylglucosamine (MurB) compared to 12-day hydrated biofilm. These three proteins are all linked with peptidoglycan biosynthesis pathway and are responsible for cell-wall formation and thicker EPS matrix deposition. Increased cell-wall formation may contribute to the persistence of DSB on dry surfaces. In contrast, proteins associated with energy metabolisms such as phosphoribosyl transferase (PyrR), glucosamine--fructose-6-phosphate aminotransferase (GlmS), galactose-6-phosphate isomerase (LacA), and argininosuccinate synthase (ArgG) were significantly upregulated whereas ribosomal and ABC transporters were significantly downregulated in the 12-day hydrated biofilm compared to DSB. However, validation by qPCR analysis showed that the levels of gene expression identified were only partially in line with our TMT-MS quantitation analysis. For the first time, a TMT-based proteomics study with DSB has shed novel insights and provided a basis for the identification and study of significant pathways vital for biofilm biology in this reference microorganism.

The environmental footprint of single-use versus reusable cloths for clinical surface decontamination: a life cycle approach

Global sustainability is a major health concern facing our planet today. The healthcare sector is a significant contributor to environmentally damaging activity. Reusable cloths should be considered as an environmentally friendly alternative to the predominantly used single-use surface wipes in cleaning and disinfection of environmental surfaces in healthcare settings. To conduct a rapid review of current policies on surface decontamination in healthcare settings; then to carry out a life cycle impact assessment (LCIA) of reusable cotton and microfibre cloths versus conventional single-use cloths, with three compatible disinfectants. Seven countries were included in the rapid review of policies. For the LCIA, inputs, outputs, and processes across the life cycle were included, using EcoInvent database v3.7.1 and open LCIA software. Sixteen European-recommended environmental impact categories and eight human health categories were considered. Infection prevention policies examined do not require single-use wipes for cleaning and disinfection. The disinfectant with the highest environmental impact was isopropyl alcohol. The most environmentally sustainable option for clinical surface decontamination was the microfibre cloth when used with a quaternary ammonium compound. The least environmentally sustainable option was cotton with isopropyl alcohol. Impacts were primarily attributed with the use of the disinfectant agent and travel processes.

Dual functionalisation of polyurethane foam for unprecedented flame retardancy and antibacterial properties using layer-by-layer assembly of MXene chitosan with antibacterial metal particles

Antibacterial surfaces in healthcare settings are an important tool for combating the increasing threat of antibacterial drug resistance, which the global Covid-19 pandemic has further exacerbated. Herein, we report a new method to achieve dual antibacterial and flame retardant functionalities in flexible polyurethane foam (PUF) by synthesising a multifunctional coating using a layer-by-layer assembly technique. The coating consists of Ti3C2 nanosheets and chitosan as the flame retardant and metal particles (copper or silver) for the antibacterial property. Results show that the multilayer Ti3C2/CH/Ag coating possesses excellent antibacterial performance with reductions of 99.97% in gram-negative bacteria (P. aeruginosa) and 88.9% in gram-positive bacteria (S. aureus) compared with the unmodified counterpart. Compared with the pristine PUF, the multifunctional coating yielded 66.3% reductions in the PHRR, and demonstrated outstanding smoke suppression performance with a PSPR reduction of 51.6% and a TSR decline of 65.5%. Moreover, Raman spectroscopy revealed an increased graphitisation level in the residual char of the coated foam, indicating the coating's remarkable charring performance. This exceptional multifunctional performance endows the coating technology with a great potential for eradicating the fire risks of antibacterial surfaces in healthcare settings and providing furniture, interior walls and building panels with antibacterial properties.

Raman Microscopic Analysis of Dry-Surface Biofilms on Clinically Relevant Materials.

Moist/hydrated biofilms have been well-studied in the medical area, and their association with infections is widely recognized. In contrast, dry-surface biofilms (DSBs) on environmental surfaces in healthcare settings have received less attention. DSBs have been shown to be widespread on commonly used items in hospitals and to harbor bacterial pathogens that are known to cause healthcare-acquired infections (HAI). DSBs cannot be detected by routine surface swabbing or contact plates, and studies have shown DSBs to be less susceptible to cleaning/disinfection products. As DSBs are increasingly reported in the medical field, and there is a likelihood they also occur in food production and manufacturing areas, there is a growing demand for the rapid in situ detection of DSBs and the identification of pathogens within DSBs. Raman microspectroscopy allows users to obtain spatially resolved information about the chemical composition of biofilms, and to identify microbial species. In this study, we investigated Staphylococcus aureus mono-species DSB on polyvinylchloride blanks and stainless steel coupons, and dual-species (S. aureus/Bacillus licheniformis) DSB on steel coupons. We demonstrated that Raman microspectroscopy is not only suitable for identifying specific species, but it also enables the differentiation of vegetative cells from their sporulated form. Our findings provide the first step towards the rapid identification and characterization of the distribution and composition of DSBs on different surface areas.

Identifying and elucidating the resistance of Staphylococcus aureus isolated from hospital environment to conventional disinfectants

BackgroundStaphylococcus aureus is a nosocomial pathogen, detection and elucidation of its resistance mechanisms to conventional disinfectants may aid in limiting its spread on environmental surfaces in health care settings. In the current study, disinfectant susceptibility of S. aureus strains isolated from the hospital environment as well as possible associations between the presence of disinfectant-resistance genes and reduced susceptibility to disinfectants was investigated. MethodsA total of 245 samples were collected from the hospital environmental surfaces. The minimum inhibitory (MIC) and bactericidal concentrations (MBC) of disinfectants against S. aureus isolates were determined using the micro-broth dilution method. The qac genes (qacA, qacE, and qacΔE1) were detected by PCR and confirmed by sanger sequencing. ResultsA total of 47 S. aureus strains were isolated, with more than 85% of them showing methicillin resistance. The qacA, qacE, and qac∆E1 genes were found in 23.4%, 29.7%, and 4.2% isolates respectively. All the isolates with qac genes had higher MIC and MBC values to selected disinfectants. ConclusionsSignificant methicillin resistant S. aureus (MRSA) contamination in the hospital environment was detected. Furthermore, higher qac gene frequencies were found in MRSA isolates that also correlated with higher MIC/MBC values to different disinfectants. The study proposes that hospitals should develop policies to determine disinfectant MICs against the common environmental isolates to contain the spread of resistant strains.

Comparison between adenosine triphosphate bioluminescence and aerobic colony count to assess surface sanitation in the hospital environment

Background: Adenosine triphosphate bioluminescence produced by the firefly luciferase has been successfullyintroduced to verify cleaning procedures in the food industry according to the Hazard Analysis Critical Control Pointprogram.Our aim was to evaluate the reliability of bioluminescence as a tool to monitor the effectiveness of sanitation in healthcaresettings, in comparison with the microbiological gold standard.Methods: 614 surfaces of various material were randomly sampled in Policlinico University Hospital units in Palermo,Italy, to detect adenosine triphosphate bioluminescence and aerobic colony count. Linear regression model andPearson correlation coefficient were used to estimate the relationship between the two variables of the study.Results: Aerobic colony count median was 1.71 colony forming units/cm2 (interquartile range = 3.8), whereasadenosine triphosphate median was 59.9 relative light units/cm2 (interquartile range = 128.3). Pearson coefficientR2 was 0.09. Sensitivity and specificity of bioluminescence test with respect to microbiology were 46% and 71%,whereas positive predictive value and negative predictive value were 53% and 65%, respectively.Conclusion: According to our results, there seemed to be no linear correlation between aerobic colony countand adenosine triphosphate values, suggesting that current bioluminescence technology has not any proportionalrelationships with culturable microbes contaminating environmental surfaces in health-care settings.

"Our job is to break that chain of infection": Challenges environmental management services (EMS) staff face in accomplishing their critical role in infection prevention.

Contaminated surfaces in healthcare settings contribute to the transmission of nosocomial pathogens. Adequate environmental cleaning is important for preventing the transmission of important pathogens and reducing healthcare-associated infections. However, effective cleaning practices vary considerably. We examined environmental management services (EMS) staff experiences and perceptions surrounding environmental cleaning to describe perceived challenges and ideas to promote an effective environmental services program. Qualitative study. Frontline EMS staff. From January to June 2019, we conducted individual semistructured interviews with key stakeholders (ie, EMS staff) at 3 facilities within the Veterans' Affairs Healthcare System. We used the Systems Engineering Initiative for Patient Safety (SEIPS) framework (ie, people, environment, organization, tasks, tools) to guide this study. Interviews were audio-recorded, transcribed, and analyzed for thematic content. In total, 13 EMS staff and supervisors were interviewed. A predominant theme that emerged were the challenges EMS staff saw as hindering their ability to be effective at their jobs. EMS staff interviewed felt they understand their job requirements and are dedicated to their work; however, they described challenges related to feeling undervalued and staffing issues. EMS staff play a critical role in infection prevention in healthcare settings. However, some do not believe their role is recognized or valued by the larger healthcare team and leadership. EMS staff provided ideas for improving feelings of value and job satisfaction, including higher pay, opportunities for certifications and advancement, as well as collaboration or integration with the larger healthcare team. Healthcare organizations should focus on utilizing these suggestions to improve the EMS work climate.

Engaging Veterans in Identifying Key Elements of Environmental Cleaning: The Patient Perspective

Background: Contaminated surfaces in healthcare settings contribute to the transmission of pathogens. Environmental cleaning and disinfection are important for preventing pathogen transmission and reducing healthcare-associated infections (HAIs). Hospital cleanliness plays a large role in patient perception of the healthcare setting and, consequently, of patient satisfaction. However, patient perceptions of environmental cleaning remain unclear. To engage patients as part of achieving patient-centered care, we undertook a qualitative study to examine patient perspectives on environmental cleaning and disinfection in healthcare settings. Methods: We conducted semistructured qualitative interviews with 14 hospitalized patients at a large midwestern Veterans’ Administration hospital. Interviews were audio recorded, professionally transcribed verbatim, summarized in a “key domains” template developed by the research team, then coded for emerging themes. Results: Patients reported feeling satisfied with hospital cleanliness and especially the daily cleaning they observed while hospitalized. Cleaning activities highlighted included mopping and disinfecting high-touch surfaces, bathrooms, and floors. Despite this overall positive response, some patients expressed worries of being “in the way” or burdensome if they were in their rooms while staff were cleaning. One interviewee stated, “It’s easier for them if there isn’t a patient in [the room] … it’s hard to do any endeavor when you’ve got a complete stranger watching you.” Patients also acknowledged the importance of careful cleaning, especially during the COVID-19 crisis; “It’s got to be something you take seriously, especially during this pandemic.” Some patients spoke of the relationship which can develop between environmental services staff during daily hospital room cleaning. Conclusions: Patient perceptions of environmental cleaning are important to understand and incorporate into clinical practice. Overall, patients felt that their environments were clean, and they expressed confidence in the staff’s work. Interviewees additionally spoke of their own self-efficacy, saying they try to clean up after themselves and would feel comfortable speaking up if something needed to be cleaned. However, some patients acknowledged feeling burdensome to the environmental services staff if patients were present in rooms while staff cleaned. Cleaning activities may become more patient-centric if they are better planned (eg, while patient is out of the room) or based on patient preferences on time of day.Funding: NoDisclosures: None

SARS-CoV-2 Detection Rates from Surface Samples Do Not Implicate Public Surfaces as Relevant Sources for Transmission

Contaminated surfaces have been discussed as a possible source of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Under experimental conditions, SARS-CoV-2 can remain infectious on surfaces for several days. However, the frequency of SARS-CoV-2 detection on surfaces in healthcare settings and the public is currently not known. A systematic literature review was performed. On surfaces around COVID-19 cases in healthcare settings (42 studies), the SARS-CoV-2 RNA detection rates mostly were between 0% and 27% (Ct values mostly > 30). Detection of infectious SARS-CoV-2 was only successful in one of seven studies in 9.2% of 76 samples. Most of the positive samples were obtained next to a patient with frequent sputum spitting during sampling. Eight studies were found with data from public surfaces and RNA detection rates between 0% and 22.1% (Ct values mostly > 30). Detection of infectious virus was not attempted. Similar results were found in samples from surfaces around confirmed COVID-19 cases in non-healthcare settings (7 studies) and from personal protective equipment (10 studies). Therefore, it seems plausible to assume that inanimate surfaces are not a relevant source for transmission of SARS-CoV-2. In public settings, the associated risks of regular surface disinfection probably outweigh the expectable health benefits.

Coronavirus Disease 2019 (COVID-2019) Infection Among Health Care Workers and Implications for Prevention Measures in a Tertiary Hospital in Wuhan, China

Health care workers (HCWs) have high infection risk owing to treating patients with coronavirus disease 2019 (COVID-19). However, research on their infection risk and clinical characteristics is limited. To explore infection risk and clinical characteristics of HCWs with COVID-19 and to discuss possible prevention measures. This single-center case series included 9684 HCWs in Tongji Hospital, Wuhan, China. Data were collected from January 1 to February 9, 2020. Confirmed COVID-19. Exposure, epidemiological, and demographic information was collected by a structured questionnaire. Clinical, laboratory, and radiologic information was collected from electronic medical records. A total of 335 medical staff were randomly sampled to estimate the prevalence of subclinical infection among a high-risk, asymptomatic population. Samples from surfaces in health care settings were also collected. Overall, 110 of 9684 HCWs in Tongji Hospital tested positive for COVID-19, with an infection rate of 1.1%. Of them, 70 (71.8%) were women, and they had a median (interquartile range) age of 36.5 (30.0-47.0) years. Seventeen (15.5%) worked in fever clinics or wards, indicating an infection rate of 0.5% (17 of 3110) among first-line HCWs. A total of 93 of 6574 non-first-line HCWs (1.4%) were infected. Non-first-line nurses younger than 45 years were more likely to be infected compared with first-line physicians aged 45 years or older (incident rate ratio, 16.1; 95% CI, 7.1-36.3; P < .001). The prevalence of subclinical infection was 0.74% (1 of 135) among asymptomatic first-line HCWs and 1.0% (2 of 200) among non-first-line HCWs. No environmental surfaces tested positive. Overall, 93 of 110 HCWs (84.5%) with COVID-19 had nonsevere disease, while 1 (0.9%) died. The 5 most common symptoms were fever (67 [60.9%]), myalgia or fatigue (66 [60.0%]), cough (62 [56.4%]), sore throat (55 [50.0%]), and muscle ache (50 [45.5%]). Contact with indexed patients (65 [59.1%]) and colleagues with infection (12 [10.9%]) as well as community-acquired infection (14 [12.7%]) were the main routes of exposure for HCWs. In this case series, most infections among HCWs occurred during the early stage of disease outbreak. That non-first-line HCWs had a higher infection rate than first-line HCWs differed from observation of previous viral disease epidemics. Rapid identification of staff with potential infection and routine screening among asymptomatic staff could help protect HCWs.

High-speed production of antibacterial fabrics using liquid flame spray

Healthcare associated infections (HAIs) are known as one of the major problems of the modern healthcare system, which result in additional cost and mortality. It has also been shown that pathogenic bacteria are mostly transferred via surfaces in healthcare settings. Therefore, antibacterial surfaces, which include fabrics and textiles, can be used in a healthcare environment to reduce the transfer of pathogenic bacteria, hence reducing HAIs. Silver nanoparticles have been shown to have broad spectrum antibacterial properties, and therefore they have been incorporated into fabrics to provide antibacterial functionality. Liquid flame spray (LFS) nanoparticle synthesis allows nanoparticles to be produced and deposited on surfaces at speeds up to and beyond 300 m/min. Herein, LFS is used to deposit silver nanoparticles onto two fabrics that are commonly used in the hospital environment with the aim of producing antibacterial fabrics. A thin plasma coating on top of the fabrics after silver deposition is used to improve nanoparticle adhesion. Fabrics coated with silver nanoparticles demonstrated antibacterial properties against Escherichia coli. Nanoparticle imaging and surface chemical characterization are performed using scanning electron microscopy and X-ray photoelectron spectroscopy. The highlights of this research are as follows: • high-speed synthesis and deposition of silver nanoparticles on fabrics; • plasma coating onto fabrics with silver nanoparticles; • antibacterial fabrics for potential use in healthcare environments.

Artificial dry surface biofilm models for testing the efficacy of cleaning and disinfection.

Dry surface biofilms (DSB) harbouring pathogens are widespread in healthcare settings, are difficult to detect and are resistant to cleaning and disinfection interventions. Here, we describe a practical test protocol to palliate the lack of standard efficacy test methods for DSB. Staphylococcus aureus DSB were produced over a 12-day period, grown with or without the presence of organic matter, and their composition and viability were evaluated. Disinfectant treatment was conducted with a modified ASTM2967-15 test and reduction in viability, transferability and biofilm regrowth post-treatment weremeasured. Dry surface biofilms produced over a 12-day period had a similar carbohydrates, proteins and DNA content, regardless of the presence or absence of organic matter. The combination of sodium hypochlorite (1000ppm) and a microfiber cloth was only effective against DSB in the absence of organic load. With the increasing concerns of the uncontrolled presence of DSB in healthcare settings, the development of effective intervention model in the presence of organic load is appropriate for the testing of biocidal products, while the use of three parameters, log10 reduction, transferability and regrowth, provides an accurate and practical measurement of product efficacy. SIGNIFICANCE AND IMPACT OF THE STUDY: The widespread presence of biofilms on dry surfaces in healthcare settings has been recently documented. These dry surface biofilms (DSB) present an unprecedented challenge to cleaning and disinfection processes. Here, we describe a practical efficacy protocol based on an invitro Staphylococcus aureus DSB model. The protocol measures reduction in viability, transferability and biofilm regrowth post-treatment to provide altogether a practical assessment of product efficacy against dry surface biofilms.

Insight into Antimicrobial Properties via Self-Acidification of Compounds from the Molybdenum-Tungsten-Oxygen System.

This communication is focused on the synthesis, characterization and experimental proof of the mechanism of antimicrobial activity of powders from the molybdenum-tungsten-oxygen (Mo-W-O) system. Materials with a discrete ratio of Mo/W ranging from 100% MoO3 to 100% WO3 with a stepwise increase of 5-10 wt % W were synthesized by the spray drying method following calcination. Spherical hollow particles with a broad size distribution were formed and the composition influenced the crystalline phases in such a way that either pure and/or mixed oxides (Mo0.6W0.4O3) were obtained. A good correlation between composition variation and phases present on the antimicrobial activity is obtained and provides a detailed screening of the activity efficiency versus compositional transition. Antimicrobial tests were performed against a model Gram-negative bacterium (Escherichia coli). Furthermore, the mechanism of antimicrobial activity is proven by correlating the medium acidification via pH measurements to the bacteria lifespan at low pH values. The mechanism is additionally supported by the bacterial growth when a buffered nutrient medium was used, together with the evidence that the powder particles have no disruptive effect on the cell wall. Consequently, an extended mechanism is proposed for the mixed oxide, relating both the structure and solubility results. Solubility measurements displayed a steep decrease in metal ions concentration with the addition of W. A narrow compositional range was identified (80 to 60 wt % Mo) where the antimicrobial activity was present, which is concurrent with a very strong decrease in solubility. Materials within this range show adequate features for being implemented into hybrid systems consisting of inorganic materials-polymers/varnishes that can be used for touch surfaces in healthcare settings.

Transparent Copper-Based Antibacterial Coatings with Enhanced Efficacy against Pseudomonas aeruginosa.

Bacterial surface contamination is a major cause of hospital-associated infections. Antibacterial coatings can play an important role in reducing bacterial transmission via inanimate surfaces in healthcare settings. In this work, transparent copper-based antibacterial coatings were fabricated on commercial poly(vinyl fluoride) and stainless steel. Acrylated quaternized chitosan and ethylenediaminetetraacetic acid were covalently grafted on the substrate for complexation with copper ions. The number of viable Staphylococcus aureus in a droplet [containing ∼104 colony forming units (CFU)], deposited on the copper-containing coating decreased by ∼96% within 60 min at 25 °C. With Pseudomonas aeruginosa, one of the most virulent and hardest to kill bacteria, no CFU could be observed within the same time span (killing efficacy >99.8% based on the detection limit). An increase in copper release from the coating was observed in the presence of P. aeruginosa, which was postulated to be due to the proteolytic activity of P. aeruginosa. The higher efficacy of the coating against P. aeruginosa compared to S. aureus is thus attributed to this increased copper release from the coating, which resulted in extensive bacterial membrane damage and death. The copper-containing coating on poly(vinyl fluoride) retained its antibacterial efficacy after 100 wipes with a water-wetted cloth or isopropanol wipes, demonstrating its durability and long-term efficacy. The coating did not exhibit significant cytotoxicity toward mammalian fibroblasts, further demonstrating its potential for mitigating bacterial transmission in a clinical setting.

Evaluation of disinfectants and wiping substrates combinations to inactivate Staphylococcus aureus on Formica coupons

Effective disinfection in healthcare facilities prevents healthcare-associated infections. This study evaluated the ability of Environmental Protection Agency-approved disinfectants (quaternary ammonium compound, QAC; sodium hypochlorite, and hydrogen peroxide) applied with 3 wiping substrates (microfiber, nonwoven, and cotton) to remove Staphylococcus aureus from Formica surfaces. All treatments reduced S aureus on Formica squares with the exception of QAC applied with cotton and QAC, nondisinfectant, and control applied with a nonwoven cloth. Sodium hypochlorite or hydrogen peroxide applied with cotton or microfiber, respectively, may be the best choice for disinfection of Formica surfaces in healthcare settings.

Beware biofilm! Dry biofilms containing bacterial pathogens on multiple healthcare surfaces; a multi-centre study

Wet biofilms associated with medical devices have been widely studied and their link with healthcare-associated infections (HCAIs) is well recognized. Little attention has been paid to the presence of dry biofilms on environmental surfaces in healthcare settings. To investigate the occurrence, prevalence, and diversity of dry biofilms on hospital surfaces. Sixty-one terminally cleaned items were received from three different UK hospitals. The presence of dry biofilm was investigated using culture-based methods and scanning electron microscopy (SEM). Bacterial diversity within biofilms was investigated using ribosomal RNA intergenic spacer analysis (RISA)-polymerase chain reaction and next-generation sequencing. Multi-species dry biofilms were recovered from 95% of 61 samples. Abundance and complexity of dry biofilms were confirmed by SEM. All biofilms harboured Gram-positive bacteria including pathogens associated with HCAI; 58% of samples grew meticillin-resistant Staphylococcus aureus. Dry biofilms had similar physical composition regardless of the type of items sampled or the ward from which the samples originated. There were differences observed in the dominance of particular species: dry biofilms from two hospitals contained mostly staphylococcal DNA, whereas more Bacillus spp. DNA was found on surfaces from the third hospital. The presence of dry biofilms harbouring bacterial pathogens is virtually universal on commonly used items in healthcare settings. The role of dry biofilms in spreading HCAIs may be underestimated. The risk may be further exacerbated by inefficient cleaning and disinfection practices for hospital surfaces.

Silver-, calcium-, and copper molybdate compounds: Preparation, antibacterial activity, and mechanisms.

Developing novel compounds with antimicrobial properties can be an effective approach to decreasing the number of healthcare-associated infections, particularly in the context of medical devices and touch surfaces. A variety of molybdate powders (Ag2MoO4, CaMoO4, CuMoO4 and Cu3Mo2O9) were synthesized and characterized, and Escherichia coli was used as a model gram-negative bacterium to demonstrate their antimicrobial properties. Optical density measurements, bacterial colony growth, and stained gel images for protein expression clearly showed that silver- and copper molybdates inhibit bacterial growth, whereas CaMoO4 exhibited no bactericidal effect. All tests were performed in both daylight and darkness to assess the possible contribution of a photocatalytic effect on the activity observed. The main mechanism responsible for the antibacterial effect observed for Ag2MoO4 is related to Ag+ release in combination with medium acidification, whereas for compounds containing copper, leaching of Cu2+ ions is proposed. All these effects are known to cause damage at the cellular level. A photocatalytic contribution to the antibacterial activity was not clearly observable. Based on the pH and solubility measurements performed for powders in contact with various media (ultrapure water and bacterial growth medium), silver molybdate (Ag2MoO4) was identified as the best antibacterial candidate. This compound has great potential for further use in hybrid powder-polymer/varnish systems for touch surfaces in healthcare settings.