Continuous room decontamination technologies

Ag2O-Containing Biocidal Interpolyelectrolyte Complexes on Glass Surfaces-Adhesive Properties of the Coatings

Biocidal coatings are of great interest to the healthcare system. In this work, the biocidal activity of coatings based on a complex biocide containing polymer and inorganic active antibacterial components was studied. Silver oxide was distributed in a matrix of a positively charged interpolyelectrolyte complex (IPEC) of polydiallyldimethylammonium chloride (PDADMAC) and sodium polystyrene sulfonate (PSS) using ultrasonic dispersion, forming nanoparticles with an average size of 5-6 nm. The formed nanoparticles in the matrix are not subject to agglomeration and changes in morphology during storage. It was found that the inclusion of silver oxide in a positively charged IPEC allows a more than 4-fold increase in the effectiveness of the complex biocide against E. coli K12 in comparison with the biocidal effect of PDADMAC and IPEC. Polycation, IPEC, and the IPEC/Ag2O ternary complex form coatings on the glass surface due to electrostatic adsorption. Adhesive and cohesive forces in the resulting coatings were studied with micron-scale coatings using dynamometry. It was found that the stability of the coating is determined primarily by adhesive interactions. At the macro level, it is not possible to reliably identify the role of IPEC formation in adhesion. On the other hand, use of the optical tweezers method makes it possible to analyze macromolecules at the submicron scale and to evaluate the multiple increase in adhesive forces when forming a coating from IPEC compared to coatings from PDADMAC. Thus, the application of ternary IPEC/Ag2O complexes makes it possible to obtain coatings with increased antibacterial action and improved adhesive characteristics.

úNo touch..Ñ methods for health care room disinfection: Focus on clinical trials

BACKGROUND

Hospital patient room surfaces are frequently contaminated with multidrug-resistant organisms. Since studies have demonstrated that inadequate terminal room disinfection commonly occurs, ..úno touch..Ñ methods of terminal room disinfection have been developed such as ultraviolet light (UV) devices and hydrogen peroxide (HP) systems.

METHODS

This paper reviews published clinical trials of ..úno touch..Ñ methods and ..úself-disinfecting..Ñ surfaces.

RESULTS

Multiple papers were identified including clinical trials of UV room disinfection devices (N.ß=.ß20), HP room disinfection systems (N.ß=.ß8), handheld UV devices (N.ß=.ß1), and copper-impregnated or coated surfaces (N.ß=.ß5). Most but not all clinical trials of UV devices and HP systems for terminal disinfection demonstrated a reduction of colonization/infection in patients subsequently housed in the room. Copper-coated surfaces were the only ..úself-disinfecting..Ñ technology evaluated by clinical trials. Results of these clinical trials were mixed.

DISCUSSION

Almost all clinical trials reviewed used a ..úweak..Ñ design (eg, before-after) and failed to assess potential confounders (eg, compliance with hand hygiene and environmental cleaning).

CONCLUSIONS

The evidence is strong enough to recommend the use of a ..úno-touch..Ñ method as an adjunct for outbreak control, mitigation strategy for high-consequence pathogens (eg, Candida auris or Ebola), or when there are an excessive endemic rates of multidrug-resistant organisms.

Airborne transmission of biological agents within the indoor built environment: a multidisciplinary review

The nature and airborne dispersion of the underestimated biological agents, monitoring, analysis and transmission among the human occupants into building environment is a major challenge of today. Those agents play a crucial role in ensuring comfortable, healthy and risk-free conditions into indoor working and leaving spaces. It is known that ventilation systems influence strongly the transmission of indoor air pollutants, with scarce information although to have been reported for biological agents until 2019. The biological agents' source release and the trajectory of airborne transmission are both important in terms of optimising the design of the heating, ventilation and air conditioning systems of the future. In addition, modelling via computational fluid dynamics (CFD) will become a more valuable tool in foreseeing risks and tackle hazards when pollutants and biological agents released into closed spaces. Promising results on the prediction of their dispersion routes and concentration levels, as well as the selection of the appropriate ventilation strategy, provide crucial information on risk minimisation of the airborne transmission among humans. Under this context, the present multidisciplinary review considers four interrelated aspects of the dispersion of biological agents in closed spaces, (a) the nature and airborne transmission route of the examined agents, (b) the biological origin and health effects of the major microbial pathogens on the human respiratory system, (c) the role of heating, ventilation and air-conditioning systems in the airborne transmission and (d) the associated computer modelling approaches. This adopted methodology allows the discussion of the existing findings, on-going research, identification of the main research gaps and future directions from a multidisciplinary point of view which will be helpful for substantial innovations in the field.

Comparative Assessment of Pulsed and Continuous LED UV-A Lighting for Disinfection of Contaminated Surfaces

The germicidal efficacy of LED UV-A lighting has scarcely been compared in continuous and pulsed modes for contaminated surfaces. Herein, we compare the disinfection properties of pulsed versus continuous lighting at equal irradiances using a 365 nm LED device that replicates the doses of occupied-space continuous disinfection UV-A products. Representative organisms evaluated in this study included human-infectious enveloped and non-enveloped viruses (lentivirus and adeno-associated virus, respectively), a bacterial endospore (Bacillus atrophaeus), and a resilient gram-positive bacterium (Enterococcus faecalis). Nominal UV-A irradiances were tested at or below the UL standard limit for continuous human exposure (maximum irradiance of 10 W/m2). We observed photoinactivation properties that varied by organism type, with bacteria and enveloped virus being more susceptible to UV-A than non-enveloped virus and spores. Overall, we conclude that continuous-mode UV-A lighting is better suited for occupied-space disinfection than pulsing UV-A at equivalent low irradiances, and we draw comparisons to other studies in the literature.

Certain Rooms in Intensive Care Units May Harbor Risk for Clostridioides difficile Infection

Abstract Background: Clostridioides difficile infection (CDI) is a common and sometimes life-threatening illness. Patient-, care-, and room hygiene-specific factors are known to impact CDI genesis, but care provider training and room topography have not been explored. We sought to determine if care in specific intensive care unit (ICU) rooms asymmetrically harbored CDI cases. Patients and Methods: Surgical intensive care unit (SICU) patients developing CDI (July 2009 to June 2018) were identified and separated by service (green/gold). Each service cared for their respective 12 rooms, otherwise differing only in resident team composition (July 2009 to August 2017: green, anesthesia; gold, surgery; August 2017 to June 2018: mixed for both). Fixed/mobile room features and provider traffic in three room zones (far/middle/near in relation to the toilet) were compared between high-/low-incidence rooms using observation via telecritical care video cameras. Results: Seventy-four new CDI cases occurred in 7,834 consecutive SICU admissions. In period one, green CDI cases were almost double gold cases (39 vs. 21; p = 0.02) but were similar in period two in which trainee service allocation intermixed. High-incidence rooms had closer toilet-to-intravenous pole proximity than low-incidence rooms (7.7 + 1.8 feet vs. 3.9 + 1.5 feet; p = 0.02). High-incidence rooms consistently housed mobile objects (patient bed, table-on-wheels) farther away from the toilet. Although physician time spent in each zone was similar, nurses spending more than 15 minutes in-room more frequently stayed in the far/middle zones in high-incidence rooms. Conclusions: Distinct SICU room features relative to toilet location and bedside clinician behaviors interact to alter patient CDI acquisition risk. This suggests that CDI risk occurs as a structural aspect of ICU care, offering the potential to reduce patient risk through deliberate room redesign.

Effectiveness of a UVC air disinfection system for the HVAC of an ICU

Ultraviolet germicidal irradiation (UVGI) uses short-wave ultraviolet (UVC) light to inactivate organisms like viruses, bacteria, and fungi. UVC inactivates a wide range of microorganisms by damaging the structure of nucleic acids and proteins at the molecular level, so they become unable to replicate and cause disease. Thus, UVC can improve indoor air quality by controlling bioaerosols and can be used as an engineering device to interrupt the transmission of pathogenic organisms and potential bioterrorism agents. Recently, the World Health Organization recognized that the COVID-19 virus could be transmitted across large distances, suggesting that indoor ventilation is key in airborne transmission. As a test for the future dissemination of UVC light installations to improve indoor air quality in Hospitals in Sergipe State, Brazil, we made a first installation of UVGI disinfection lamps, strategically placed in the Heating, Ventilating, and Air Conditioning (HVAC) system of the Intensive Care Unit (ICU) at the University Hospital of Lagarto, Federal University of Sergipe, Brazil. Six 15 W low-vapor-pressure mercury lamps emitting 253.7 nm UVGI were installed in the ducts of the fan coil, maximizing their luminous interaction in the air passage. One of the greatest advantages of this type of installation is that the lamps were completely covered, avoiding any risk of hazardous exposure to people and animals. Microbiological tests were carried out to verify the germicidal effect, analyzing the viability of microorganisms circulating in the environment. In this paper, we present our encouraging results, demonstrating the effectiveness of the installation, suggesting that similar devices should be installed in HVAC systems to avoid biological risk to people inside buildings. In addition, we believe that this study may provide useful evidence and guidance for the design of equipment intended to abate the microorganisms that may be used in CBRNE terror attacks.

Antimicrobial coatings for environmental surfaces in hospitals: a potential new pillar for prevention strategies in hygiene

Recent reports provide evidence that contaminated healthcare environments represent major sources for the acquisition and transmission of pathogens. Antimicrobial coatings (AMC) may permanently and autonomously reduce the contamination of such environmental surfaces complementing standard hygiene procedures. This review provides an overview of the current status of AMC and the demands to enable a rational application of AMC in health care settings. Firstly, a suitable laboratory test norm is required that adequately quantifies the efficacy of AMC. In particular, the frequently used wet testing (e.g. ISO 22196) must be replaced by testing under realistic, dry surface conditions. Secondly, field studies should be mandatory to provide evidence for antimicrobial efficacy under real-life conditions. The antimicrobial efficacy should be correlated to the rate of nosocomial transmission at least. Thirdly, the respective AMC technology should not add additional bacterial resistance development induced by the biocidal agents and co- or cross-resistance with antibiotic substances. Lastly, the biocidal substances used in AMC should be safe for humans and the environment. These measures should help to achieve a broader acceptance for AMC in healthcare settings and beyond. Technologies like the photodynamic approach already fulfil most of these AMC requirements.

Role of the Healthcare Surface Environment in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Transmission and Potential Control Measures

The healthcare environment serves as one of the possible routes of transmission of epidemiologically important pathogens, but the role of the contaminated environment on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission remains unclear. We reviewed survival, contamination, and transmission of SARS-CoV-2 via environmental surfaces and shared medical devices as well as environmental disinfection of SARS-CoV-2 in healthcare settings. Coronaviruses, including SARS-CoV-2, have been demonstrated to survive for hours to days on environmental surfaces depending on experimental conditions. The healthcare environment is frequently contaminated with SARS-CoV-2 RNA in most studies but without evidence of viable virus. Although direct exposure to respiratory droplets is the main transmission route of SARS-CoV-2, the contaminated healthcare environment can potentially result in transmission of SARS-CoV-2 as described with other coronaviruses such as SARS and Middle East respiratory syndrome coronaviruses. It is important to improve thoroughness of cleaning/disinfection practices in healthcare facilities and select effective disinfectants to decontaminate inanimate surfaces and shared patient care items.

Evaluation of a continuously active disinfectant for decontamination of portable medical equipment

A single spray application of a continuously active disinfectant on portable equipment resulted in significant reductions in aerobic colony counts over 7 days and in recovery of Staphylococcus aureus and enterococci: 3 of 93 cultures (3%) versus 11 of 97 (11%) and 20 of 97 (21%) in quaternary ammonium disinfectant and untreated control groups, respectively.

Penetration of Singlet Oxygen into Films with Oxygen Permeability Coefficient Close to that of Skin

Although its antiviral and antibacterial functions help prevent infection, singlet oxygen (¹ O₂ )-which is generated by the action of light on an endogenous photosensitizer-is cytotoxic. In the present study, we investigated the ability of ¹ O₂ -generated by the action of visible light on a photosensitizer-to penetrate skin. We used two polymer films with oxygen permeability coefficients similar to that of skin-i.e. cellulose acetate (CA) and ethyl cellulose (EC). Both films contained 1,3-diphenylisobenzofuran (DPBF), which was used as an ¹ O₂ probe. ¹ O₂ generated externally did not permeate the films by mere contact. Therefore, we conclude that the potential for ¹ O₂ to penetrate the skin is very low, and films that generate ¹ O₂ are safe and useful for preventing infections by contact. We also proved that ¹ O₂ can move between the layers of integrated polymer films when they are joined together.

Antimicrobial efficacy and durability of copper formulations over one year of hospital use

OBJECTIVE

To evaluate 3 formulations of copper (Cu)-based self-sanitizing surfaces for antimicrobial efficacy and durability over 1 year in inpatient clinical areas and laboratories.

DESIGN

Randomized control trial.

SETTING

We assessed 3 copper formulations: (1) solid alloy 80% Cu-20% Ni (integral copper), (2) spray-on 80% Cu-20% Ni (spray-on) and (3) 16% composite copper-impregnated surface (CIS). In total, 480 coupons (1 cm2) of the 3 products and control surgical grade (AISI 316) stainless steel were inserted into gaskets and affixed to clinical carts used in patient care areas (including emergency and maternity units) and on microbiology laboratory bench work spaces (n = 240). The microbial burden and assessment of resistance to wear, corrosion, and material compatibility were determined every 3 months. Participants included 3 tertiary-care Canadian adult hospital and 1 pediatric-maternity hospital.

RESULTS

Copper formulations used on inpatient units statistically significantly reduced bacterial bioburden compared to stainless steel at months 3 and 6. Only the integral copper product had significantly less bacteria than stainless steel at month 12. No statistically significant differences were detected in microbial burden between copper formulations and stainless-steel coupons on microbiology laboratory benches where bacterial counts were low overall. All mass changes and corrosion rates of the formulations were acceptable by engineering standards.

CONCLUSIONS

Copper surfaces vary in their antimicrobial efficacy after 1 year of hospital use. Frequency of cleaning and disinfection influence the impact of copper; the greatest reduction in microbial bioburden occurred in clinical areas compared to the microbiology laboratory where cleaning and disinfection were performed multiple times daily.

Potential of Therapeutic Bacteriophages in Nosocomial Infection Management

Nosocomial infections (NIs) are hospital-acquired infections which pose a high healthcare burden worldwide. The impact of NIs is further aggravated by the global spread of antimicrobial resistance (AMR). Conventional treatment and disinfection agents are often insufficient to catch up with the increasing AMR and tolerance of the pathogenic bacteria. This has resulted in a need for alternative approaches and raised new interest in therapeutic bacteriophages (phages). In contrast to the limited clinical options available against AMR bacteria, the extreme abundance and biodiversity of phages in nature provides an opportunity to establish an ever-expanding phage library that collectively provides sustained broad-spectrum and poly microbial coverage. Given the specificity of phage-host interactions, phage susceptibility testing can serve as a rapid and cost-effective method for bacterial subtyping. The library can also provide a database for routine monitoring of nosocomial infections as a prelude to preparing ready-to-use phages for patient treatment and environmental sterilization. Despite the remaining obstacles for clinical application of phages, the establishment of phage libraries, pre-stocked phage vials prepared to good manufacturing practice (GMP) standards, and pre-optimized phage screening technology will facilitate efforts to make phages available as modern medicine. This may provide the breakthrough needed to demonstrate the great potential in nosocomial infection management.

Colorimetric detection of residual quaternary ammonium compounds on dry surfaces and prediction of antimicrobial activity using bromophenol blue

Controlling and monitoring the residual activity of quaternary ammonium compounds (QACs) are critical for maintaining safe yet effective levels of these agents in the environment. This study investigates the utility of bromophenol blue (BPB) as a safe, rapid and user-friendly indicator to detect in situ residual QACs dried on hard, non-porous surfaces, as well a means to assess their antimicrobial efficacy. At pH 7, BPB has a purple colour which turns blue upon its complexation with QACs such as didecyldimethylammonium chloride (DDAC). BPB itself has no antimicrobial properties up to 400 ppm. Within the range of 0-400 ppm, BPB colour change was tied to specific DDAC antimicrobial performances with a detection threshold of 100 ppm. BPB concentration and application volume could be adjusted such that a colour shift from purple to blue correlated with a set percent reduction (>99·9%) in test bacteria (Staphylococcus aureus and Klebsiella aerogenes). The BPB solutions developed in this study yielded similar colour shifts on polycarbonate and stainless steel surfaces and did not cross-react with chemical ingredients commonly found in sanitizers and disinfectant products. Overall, this study suggests that BPB provides a simple solution to safely monitor the post-application level and biocidal activity of residual dried QACs on surfaces.

Aerosol disinfection of bacterial spores by peracetic acid on antibacterial surfaces and other technical materials

BACKGROUND

The effectiveness of aerosol disinfection processes based on peracetic acid (PAA) might differ depending on the surface targeted. Especially antibacterial, oligodynamic materials have to be regarded as they could cause elevated decomposition of PAA.

AIM

This study aimed on the determination of differences in disinfection effectiveness using PAA caused by the treated material.

METHODS

Aerosol disinfection of Geobacillus stearothermophilus spores was performed on the antibacterial, oligodynamic materials copper and brass in comparison to stainless steel and aluminium as well as polyvinylchloride, wood, and ceramics. Additionally, the influence of the materials on the decomposition reaction of PAA was evaluated.

RESULTS

For aluminium and stainless steel as well as ceramics and polyvinylchloride, a disinfection of 10⁶ spores of Geobacillus stearothermophilus on 40 cm² was obtained by the employment of 60 mL aerosolized disinfectant/m³ on laboratory scale (0.5 m³). For the application on the oligodynamic materials copper and brass an over 30% higher amount of disinfectant was necessary to achieve significant disinfection results, than for the other material surfaces. In contrast to aluminium and stainless steel, copper and brass caused elevated decomposition of PAA what seems to be the reason for the lowered disinfection effectiveness.

CONCLUSIONS

Applying aerosol disinfection processes, in addition to parameters such as room size and geometry, the treated materials have to be considered when determining the necessary amount of disinfectant.

Surface Disinfection to Protect against Microorganisms: Overview of Traditional Methods and Issues of Emergent Nanotechnologies

Sterilization methods for individuals and facilities are extremely important to enable human beings to continue the basic tasks of life and to enable safe and continuous interaction of citizens in society when outbreaks of viral pandemics such as the coronavirus. Sterilization methods, their availability in gatherings, and the efficiency of their work are among the important means to contain the spread of viruses and epidemics and enable societies to practice their activities almost naturally. Despite the effective solutions given by traditional methods of surface disinfection, modern nanotechnology has proven to be an emergent innovation to protect against viruses. On this note, recent scientific breakthroughs have highlighted the ability of nanospray technology to attach to air atoms in terms of size and time-period of existence as a sterilizer for renewed air in large areas for human gatherings. Despite the ability of this method to control the outbreak of infections, the mutation of bactericidal mechanisms presents a great issue for scientists. In recent years, science has explored a more performant approach and techniques based on a surface-resistance concept. The most emergent is the self-defensive antimicrobial known as the self-disinfection surface. It consists of the creation of a bacteria cell wall to resist the adhesion of bacteria or to kill bacteria by chemical or physical changes. Besides, plasma-mediated virus inactivation was shown as a clean, effective, and human healthy solution for surface disinfection. The purpose of this article is to deepen the discussion on the threat of traditional methods of surface disinfection and to assess the state of the art and potential solutions using emergent nanotechnology.

Keeping a 2009 Design Award-Winning Intensive Care Unit Current: A 13-Year Case Study

In a complex medical center environment, the occupants of newly built or renovated spaces expect everything to "function almost perfectly" immediately upon occupancy and for years to come. However, the reality is usually quite different. The need to remediate initial design deficiencies or problems not noted with simulated workflows may occur. In our intensive care unit (ICU), we were very committed to both short-term and long-term enhancements to improve the built and technological environments in order to correct design flaws and modernize the space to extend its operational life way beyond a decade. In this case study, we present all the improvements and their background in our 20-bed, adult medical-surgical ICU. This ICU was the recipient of the Society of Critical Care Medicine's 2009 ICU Design Award Citation. Our discussion addresses redesign and repurposing of ICU and support spaces to accommodate expanding clinical or entirely new programs, new regulations and mandates; upgrading of new technologies and informatics platforms; introducing new design initiatives; and addressing wear and tear and gaps in security and disaster management. These initiatives were all implemented while our ICU remained fully operational. Proposals that could not be implemented are also discussed. We believe this case study describing our experiences and real-life approaches to analyzing and solving challenges in a dynamic environment may offer great value to architects, designers, critical care providers, and hospital administrators whether they are involved in initial ICU design or participate in long-term ICU redesign or modernization.

The effect of copper-oxide-treated soft and hard surfaces on the incidence of healthcare-associated infections: a two-phase study

BACKGROUND

Copper-oxide-impregnated linens and hard surfaces within the hospital environment have emerged as a novel technology to reduce environmental contamination and thereby potentially reduce the risk of healthcare-associated infections (HCAIs).

METHODS

This was a two-phase study. Phase 1 was a prospective, cluster-randomized, cross-over clinical trial in which one pod (eight beds) of our general ICU (GICU) utilized copper-oxide-impregnated linens whereas the other pod (eight beds) used standard hospital linens. Phase 2 was a two-year before-after study, following the relocation of three ICUs into a new ICU tower in which all the hard surfaces were treated with copper oxide (in addition to copper-impregnated linens). HCAIs were recorded using the National Healthcare Safety Network definitions.

FINDINGS

A total of 1282 patients were enrolled in phase 1. There was no difference in the rate of HCAI between the patients who received standard compared with copper oxide linen. In phase 2 there was a significant reduction in the number of infections due to Clostridioides difficile (2.4 per 1000 vs 0.7 per 1000 patient-days; incidence rate ratio: 3.3; 95% confidence interval: 1.4-8.7; P = 0.002) but no difference in the rate of central-line-associated bloodstream infections nor of catheter-associated urinary tract infections.

CONCLUSION

Copper-oxide-impregnated linens alone had no effect on the rate of HCAI. Our data suggest that copper-oxide-treated hard surfaces reduced the rate of infections due to C. difficile; however, important confounders cannot be excluded.