Disinfection Cycles Research Articles

A novel smart disinfection system using 3D-printed and electrically conductive composite hydrogel

AbstractSmart materials are ushering in the era of smart and adaptable products. Hydrogels are a distinct class of smart materials that can be 3D-printed to produce smart and active structures that can be used as sensors and actuators. The development and characterization of a 3D-printable and electrically conductive composite hydrogel, as well as its application in the development of a smart disinfection system, are discussed in this article. The developed composite hydrogel has a maximum electrical conductivity of 145 S.m−1, is stable up to 200 °C, and has a 3D printable rheology. Virtuous of its electrical conductivity, the composite hydrogel was used to create a smart disinfection system. Various disinfection systems have been adopted for the disinfection of contaminated surfaces; however, most of these systems require human evacuation from the surroundings due to the hazardous nature of the virucide. The proposed system is designed to disinfect contaminated surfaces on common-use equipment and is capable of real-time activation through user interaction. It employs a thermal disinfection process at 60 °C for 5 min and becomes ready for the next user once its temperature drops below 55 °C. This system consumes 1.64 Wh of energy per disinfection cycle and is suitable for scenarios with fewer than 60 user interactions in an 8-h work shift.

Effect of Using Hydrogen Peroxide for Periodic Disinfection Combined With Continuous Disinfection to Control Contamination in Dental Unit Waterline

To observe the effect of using hydrogen peroxide in periodic disinfection combining with continuous disinfection of dental unit waterlines and to provide references for the selection of waterway disinfection measures. A total of 4 dental units in a hospital of stomatology were selected through convenience sampling. The dental unit waterlines received periodic disinfection once every 4 weeks in addition to continuous disinfection (When the dental units were not used for more than 3 days, an additional periodic disinfection would be performed.). Periodic disinfection referred to filling up the waterlines with a disinfectant solution (1.4% hydrogen peroxide) by using the waterline disinfection device that came with the dental unit, immersing for 24 hours, and then emptying out the disinfectant solution. Continuous disinfection referred to using hydrogen peroxide at a concentration of 0.014% as dental treatment water and using it to flush the waterlines for 2 minutes before any dental treatment in the morning and to flush the waterlines for 30 seconds after each dental treatment. The study lasted for 25 weeks, with periodic disinfection being performed for 7 times and continuous disinfection carried out for the rest of the dental treatment time. During the 25 weeks, water samples were collected from air/water syringes and high-speed handpieces. Then, the water samples were incubated and the bacterial concentration and the qualification rates were calculated accordingly. When the bacterial concentration≤100 CFU/ mL, the water samples were considered to be qualified. Waterline tubes of 1 cm were collected before and after the 25 weeks of disinfection with hydrogen peroxide. Biofilms in the waterline tube were observed under scanning electron microscope. A total of 352 water samples were collected. Eight water samples were collected before disinfection with hydrogen peroxide, with the median of bacterial concentration being 3140 CFU/mL. On the first day of disinfection with hydrogen peroxide, the median bacterial concentration in dental treatment water was 7.5 CFU/mL. There was a significant difference between the bacterial concentration of the water samples before the disinfection and that after the disinfection (P=0.012). A total of 344 water samples were collected after the disinfection, with the median bacterial concentrations for air/water syringes and high-speed handpieces being 11 CFU/mL and 11CFU/mL and the qualified rates being 83.7% and 82.0%, respectively. There was no significant difference in bacterial concentration or the qualification rates. During week 1 through week 9 of the disinfection, the qualification rates of the dental treatment water always exceeded 80% in 8 weeks, with week 3 being the exception. In the two four-week disinfection periods of week 14 through week 17 and week 18 through week 21, the qualification rate was maintained at above 80% for only the first two weeks and started to decrease from the third week. Biofilm morphology was observed under scanning electron microscope. Before the disinfection, the biofilm was found to be a dense structure and the mixture of a large number of bacteria. After 25 weeks of the disinfection, the biofilm structure appeared to be loose and did not show consistent characteristics of a large number of bacteria retained. Periodic disinfection combined with continuous disinfection using hydrogen peroxide can effectively control contamination in dental unit waterlines. But the cycles of periodic disinfection and the concentration of hydrogen peroxide for continuous disinfection should be further discussed according to the actual clinical situation.

Effect of Different Disinfecting Agents on Surface Roughness and Color Stability of Heat-cure Acrylic Denture Material: An In Vitro Study.

The current study aimed to determine the impact of three different disinfectants on the surface roughness and color stability of heat-cure acrylic denture material. Using a stainless-steel mold, disc-shaped wax patterns with dimensions of 10 mm in diameter and 2 mm thick (in accordance with ADA Specification No. 12) were created and prepared for a total of 75 acrylic samples. Dimensions of all 75 acrylic samples were checked with a digital Vernier caliper. About 25 samples of denture base material were immersed in three different chemical disinfectants: Group I: immersed in chlorhexidine gluconate solution, group II: immersed in sodium hypochlorite solution, and group III: immersed in glutaraldehyde solution. All samples were scrubbed daily for 1 minute with the appropriate disinfectant and submerged for 10 minutes in the same disinfectant. Between disinfection cycles, samples were kept in distilled water at 37°C. Color stability was measured using a reflection spectrophotometer. Surface roughness values were measured by a profilometer at baseline following 15 days and 30 days. After 15 days, the color stability was better in chlorhexidine gluconate solution group (4.88 ± 0.24) than sodium hypochlorite solution (4.74 ± 0.18) and glutaraldehyde solution group (4.46 ± 0.16). The mean surface roughness was less in glutaraldehyde solution group (2.10 ± 0.19), followed by chlorhexidine gluconate solution group (2.48 ± 0.09) and sodium hypochlorite solution group (2.64 ± 0.03). After 30 days, the color stability was significantly better in chlorhexidine gluconate solution group (4.40 ± 0.02), followed by sodium hypochlorite solution (4.06 ± 0.16) and glutaraldehyde solution group (3.87 ± 0.17). The mean surface roughness was significantly lesser in glutaraldehyde solution group (2.41 ± 0.14), followed by chlorhexidine gluconate solution group (2.94 ± 0.08) and sodium hypochlorite solution group (3.02 ± 0.13). In conclusion, the color stability was significantly better in chlorhexidine gluconate solution group than sodium hypochlorite solution and glutaraldehyde solution group. But the surface roughness was significantly lesser in the glutaraldehyde solution group, followed by the chlorhexidine gluconate and sodium hypochlorite solution group. The maintenance of the prosthesis requires the use of a denture disinfectant; therefore, it is crucial to select one that is effective but would not have a negative impact on the denture base resin's inherent characteristics over time. How to cite this article: Kannaiyan K, Rakshit P, Bhat MPS, et al. Effect of Different Disinfecting Agents on Surface Roughness and Color Stability of Heat-cure Acrylic Denture Material: An In Vitro Study. J Contemp Dent Pract 2023;24(11):891-894.

Gravity driven ceramic membrane loaded birnessite functional layer for manganese removal from groundwater: The significance of disinfection on biofilm

Gravity-Driven Ceramic Membrane (GDCM) technology has gained popularity and recognition in water purification on account of its low energy consumption and convenient operation. This study aimed to comprehensively assess the effects of different disinfectants, including hydrogen peroxide (H2O2) and sodium hypochlorite (NaClO), on GDCM performance. It focused on the change in manganese removal and structure of the powdered activated carbon (PAC) - manganese oxides (MnOx) pre-deposited at the membrane interface and as well membrane fouling mitigation. The results showed that after the first two disinfection cycles, the flux recovery was 15 LMH for H2O2, while using NaClO only achieved an average recovery of 2 LMH and increased the effluent manganese, exceeding 0.1 mg/L within a short period of time. During the disinfection process, H2O2 exhibited better performance in mitigating membrane fouling compared to NaClO in the GDCM system. Additionally, by observing the recovery time of Mn2+ after disinfection, it can be deduced that the initial manganese removal mainly resulted from biological action of manganese-oxidizing bacteria (MnOB), while the later stage relied primarily on the catalytic oxidation action of birnessite. Fluorescence excitation–emission matrix analysis (EEM) indicated that most organic compounds dissolved in the disinfectant solution after disinfection, with some permeating through the membrane, while the remaining portion continued to accumulate in the filter cake layer. This accumulation was further confirmed by the enhanced absorbance peaks of functional groups (–NH and –OH) in the Fourier-transform infrared spectroscopy (FTIR). Scanning electron microscope - energy dispersive x-ray spectroscopy (SEM-EDS) mapping analysis revealed that MnOx formed more lamellar structures between nano-flower balls after disinfection. This increased the number of active sites and opened up water flow channels, contributing to improved flux. X-ray photoelectron spectroscopy (XPS) analysis demonstrated that Mn3+ as the dominant valence in MnOx exhibited excellent catalytic oxidation ability. Raman analysis and X-ray diffraction (XRD) indicated that MnOx showed consistent Raman spectra with birnessite before and after disinfection, and the oxidative effect of disinfection did not alter the crystal structure of MnOx. This result demonstrates the importance of applying effective disinfection in the GDCMs.

Feasibility study of reusing surgical masks and evaluation of the effectiveness of different disinfection methods

This study assessed various disinfection methods' impact on surgical mask reusability amid the high demand and limited supply of medical surgical masks during the respiratory disease pandemic. Volunteers wore masks for 4 h, and masks were disinfected using methods including moist heat, dry heat, ultraviolet (UV) radiation, alcohol soaking, washing machine cleaning, ultrasonic cleaning, or microwave disinfection. Key indicators measured included filtration efficiency, mask pressure, electrostatic charge, tensile strength, and blood penetration. Scanning electron microscopy and 16S bacterial DNA testing were used to evaluate fiber changes and disinfection effectiveness. After three disinfection cycles using any method, masks met Chinese standard YY0469-2011 requirements for filtration efficiency, mask pressure, strength, and blood penetration. However, non-oily particle filtration efficiency significantly decreased with moist heat, alcohol soaking, or machine washing. Bacterial filtration efficiency decreased with dry heat, alcohol soaking, or machine washing. All disinfection methods caused structural changes, particularly with dry heat, ultrasonic cleaning, and microwave disinfection. UV radiation effectively sterilized masks while maintaining filtration performance, making it the preferred method for mask reuse in emergencies.

455 Performance of a breath-enhanced nebulizer after repeated cycles of thermal or chemical disinfection

455 Performance of a breath-enhanced nebulizer after repeated cycles of thermal or chemical disinfection

Effect of 3 different disinfection methods on the image quality of photostimulable phosphor plates

The aim of this study was to assess the effects of 3 disinfection protocols on the quality of images acquired with a photostimulable phosphor (PSP) plate system. Thirty DIGORA Optime PSP plates were divided into 3 groups of 10. Group 1 was disinfected with 95% ethanol. Group 2 was disinfected using germicidal disposable wipes. Group 3 was disinfected with 95% ethanol, followed by hydrogen peroxide gas sterilization. Images of a quality assurance phantom were acquired on each plate before disinfection (baseline images). Disinfection and imaging cycles were repeated 45 times for each plate. Changes in image quality were assessed between baseline and final images. Image quality was evaluated for dynamic range, spatial resolution, and contrast perceptibility. The Fisher exact test was used to detect statistically significant differences among the 3 disinfection methods relative to decreases in image quality parameters between the baseline and final radiographs. Additionally, for each group, the Z-test was used to detect statistically significant decreases in image quality parameters between baseline and final images. The significance level was established at P < .05. No statistically significant differences were detected among the disinfection groups or relative to baseline values for any group at a 5% significance level. Hydrogen peroxide gas may be considered to prevent cross-contamination while preserving image quality. Regular quality assurance testing is recommended to maintain image quality over time.

Design of PTFE/PP multilayer composite membrane as mask filter layer with steady filtration efficiency and high dust holding capacity

Currently, commercially available mask filter materials, such as electrostatic electret polypropylene (PP) melt-blown cloth and polytetrafluoroethylene (PTFE) nanofiber membranes, always suffer a compromise between filtration efficiency and dust holding capacity, when used alone during air purification. In this study, a novel multilayer composite membrane was designed by thermally laminating a PP melt-blown filter layer (as the dust-holding layer) and a PTFE (Polytetrafluoroethylene) nanofiber layer (as the filtration layer), to improve filtration stability and capacity. The performance of the composite membrane was examined in relation to the effect of key laminating parameters (i.e., temperature, pressure and speed) on the dust holding capacity, filtration efficiency and resistance. NaCl aerosol was used as the model dust source. Results show that the composite membrane, prepared at a lamination temperature of 120 °C, a lamination pressure of 0.2 MPa and a lamination speed of 4 m/min, had a dust-holding capacity of 12.21 g/m2, which was over six times higher than that of the PTFE nanofiber membrane alone. During ten repeated cycles of NaCl aerosol filtration, water washing and alcohol disinfection, the composite membrane exhibited a steady filtration efficiency of above 99.9% over the NaCl aerosol. Meanwhile, the dust holding capacity was maintained above 8 g/m2 over the multiple cycles, while the resistance was smaller than 70 Pa.

Применение автоматического парового стерилизатора для обеззараживания отходов иммунобиологического производства, контаминированных патогенными биологическими агентами

One of the ways to neutralize immunobiological production waste is their treatment in sterilizers with saturated water vapor under pressure. Currently, medical and pharmaceutical industries and laboratories use sterilizers with sterilization and disinfection programs preset by manufacturers. Decontamination modes are defined in Federal sanitary rules, norms and hygienic standards, SanPiN 3.3686-21, while the parameters of preliminary phases of the cycle must be tested experimentally and validated for specific conditions. Within the frames of this study, we have tested the modes of disinfection of an automatic steam sterilizer by the example of waste products from the production of cholera vaccine and anti-rabies immunoglobulin manufactured by the FSSI Russian Anti-Plague Institute «Microbe» of the Rospotrebnadzor. The wastes are used nutrient media, carcasses of laboratory animals (rabbits) and consumables. The chamber was loaded with «clean» objects in quantity and configuration, repeating the loading of material with pathogenic biological agents (PBA). The mode of inactivation inside the chamber and the objects was controlled by physical, chemical and biological methods. Based on the results of the experiments, corrective actions were taken to change the program and design of containers for autoclaving. It was concluded that the default disinfection programs set by manufacturers do not fully take into account specific conditions and need to be adjusted with further validation. It is necessary to develop standard operating procedures for personnel involved in the decontamination of pathogenic materials, in which should be stated the order of placement of objects and the means of control in the containers with PBA and the sterilizer chamber. Keywords: steam sterilizers, pathogenic biological agents, disinfection with saturated water vapor, phases of the steam disinfection cycle, validation.

Strategies for deployment of ultraviolet disinfection in an acute care facility: A quality improvement initiative

Mobile ultraviolet (UV) disinfection uses UV-C light to render microorganisms nonviable and reduce environmental transmission of pathogens in hospital settings. Optimal strategies for deployment must consider the cost, physical layout, and staffing resources. The aim of this quality improvement study was to increase UV disinfection utilization by developing novel deployment strategies without adding resources. A novel deployment strategy and tools were developed by a multidisciplinary group that included infection prevention, environmental services, and nursing unit staff. Utilization was tracked via a manufacturer-supported database. The infection prevention team analyzed the weekly UV disinfection minutes, cycles, and proportions of cycles completed in defined areas across 4 periods: baseline, pilot, baseline 2, and intervention. The median (range) disinfection cycle times per week during a geographically confined pilot (4,985minutes [3,476-6,551] minutes) and the intervention period (1,454 [512-3,085] minutes) were lower than either baseline period (5,394 [3,953-6,987] and 6,641 [2,830-7,276] minutes, respectively). Cycles per week were lower in the intervention period than in the preceding 3 periods. Use of UV disinfection in acute care settings should be guided by multidisciplinary groups balancing resources against efficacy and using tailored tools to promote efficiency.

Nanosilver/DCOIT-containing surface coating effectively and constantly reduces microbial load in emergency room surfaces

Colonization of near-patient surfaces in hospitals plays an important role as a source of healthcare-associated infections. Routine disinfection methods only result in short-term elimination of pathogens. To investigate the efficiency of a newly developed antimicrobial coating containing nanosilver in long-term reduction of bacterial burden in hospital surfaces to close the gap between routine disinfection cycles. In this prospective, double-blinded trial, frequently touched surfaces of a routinely used treatment room in an emergency unit of a level-I hospital were treated with a surface coating (nanosilver/DCOIT-coated surface, NCS) containing nanosilver particles and another organic biocidal agent (4,5-dichloro-2-octyl-4-isothiazolin-3-one, DCOIT), whereas surfaces of another room were treated with a coating missing both the nanosilver- and DCOIT-containing ingredient and served as control. Bacterial contamination of the surfaces was examined using contact plates and liquid-based swabs daily for a total trial duration of 90 days. After incubation, total microbial counts and species were assessed. In a total of 2880 antimicrobial samples, a significant reduction of the overall bacterial load was observed in the NCS room (median: 0.31 cfu/cm2; interquartile range: 0.00-1.13) compared with the control coated surfaces (0.69 cfu/cm2; 0.06-2.00; P < 0.001). The nanosilver- and DCOIT-containing surface coating reduced the relative risk of a critical bacterial load (defined as >5 cfu/cm2) by 60% (odds ratio 0.38, P < 0.001). No significant difference in species distribution was detected between NCS and control group. Nanosilver-/DCOIT-containing surface coating has shown efficiency for sustainable reduction of bacterial load of frequently touched surfaces in a clinical setting.

Efficient endoscope inner channel surface disinfection using a two-step atmospheric pressure plasma treatment

Flexible endoscopes are ubiquitously used in modern medicine to diagnose and treat a variety of gastrointestinal ailments; however, the inner channels of these complex devices provide an ideal environment for biofilm development. Incomplete or ineffective endoscope reprocessing introduces the potential for cross-contamination between patients, highlighting the need for a new approach to disinfection. In this study, the antibiofilm potential of a two-step disinfection process using cold atmospheric pressure plasma and plasma activated water is considered. It was revealed that the combined approach achieved a 5.72 log reduction of clinically relevant mixed species biofilms from the narrow lumens found within a typical endoscope. To investigate potential surface damage resulting from the decontamination process, the surface composition and morphology were examined using XPS, FTIR and AFM. Following multiple disinfection cycles, few changes to the surface composition or morphology were detected and the corresponding ability of bacteria to adhere on the surface was not enhanced.

Experimental feasibility study of multipurpose low-cost solar thermal device for different applications including inactivation of SARS CoV-2

This study show the experimental feasibility of the Solar thermal energy-based disinfection and inactivation of viruses, including the SARS CoV-2 from the different surfaces and utensils. A small prototype device is proposed and fabricated to serve the purpose. This device was tested in the field conditions using cotton clothes as a material/surface/utensil to observe the heating performance of the proposed device to attain the desired temperature range and corresponding timeline of heat-based 4 and 5 log viral load reduction/inactivation protocol. A new parameter ‘Disinfection Power’ is proposed to comment on the thermal performance of the SDC.The SDC satisfactorily reached temperatures ∼75–80 °C required for the 4 and 5 log heat-based viral load reduction protocol for disinfection cycles and maintained it for the heat for desired time line of minimum 60 min for the rated load of utensils. The value of the disinfection power at mean temperature difference (25 °C in the present case) is 29.9 W. The exergy efficiency of the SDC shows variation between 12.62 % and 22.69 %. Thus, SDC offers an affordable solution to reduce the risk of spreading the virus through contact with clothes and utensils.

1919. Implementation of Hydrogen Peroxide Vapor (HPV) Decontamination of N95 Respirators for Reuse During COVID-19 Pandemic

Abstract Background To ensure an adequate supply of N95 respirators in response to the global shortages caused by the COVID-19 pandemic, we evaluated and implemented hydrogen peroxide vapor (HPV) to reprocess disposable N95 respirators. Previous work performed by our team showed that HPV was effective in eradicating viable viruses from experimentally contaminated N95 respirators and that they retained their breathability and filtering efficiency for 3 cycles of HPV disinfection. Methods A multidisciplinary team worked by performing experiments and PDSA cycles to develop the ultimate process. Key processes and stakeholders were identified and engaged in operations decisions. Results The respirator reprocessing program was successfully implemented. One of the critical components for its success was the implementation of a Personal Protective Equipment (PPE) liaison program which was developed to create a process and local, unit-level champion for the collection of used N95s and to educate the staff on the program and provide guidance per the hospitals’ PPE policy. A courier system was implemented for the collection, transport and delivery of bulk containers of respirators between facilities. Facility Services designed and constructed a centralized respirator reprocessing center to include a receiving location, a negative pressure decontamination area to sort and stage the respirators on racks, two HPV reprocessing rooms and a clean room to receive the reprocessed N95s and to repackage and label for distribution. Standard operating procedures, staff training and competencies, and logs for documentation were created. Within 18 weeks (March 13, 2020 through July 2020), nearly 32,000 N95 respirators were reprocessed and packaged for redistribution utilizing the 2 HPV disinfection rooms and 5 full time employees. As built, there was capacity to reprocess 5,000 respirators per day and evaluated by the U. S. Food and Drug Administration (FDA) led to the issue of an Emergency Use Authorization. Conclusion This scalable program enabled YNHHS to ensure an adequate supply of respirators for the safety of staff during the COVID-19 pandemic and global shortages of PPE. A multidisciplinary team and leadership commitment to provide resources for space and personnel were critical for program success. Disclosures All Authors: No reported disclosures.

1194. Efficacy of shortened high-level disinfection (HLD) protocols for GI duodenoscopes with disposable tips used for endoscopic retrograde cholangiopancreatography (ERCP)

Abstract Background The most efficient combination of manual washes (MW) and high-level disinfection (HLD) cycles for the reprocessing of duodenoscopes used for ERCP is unknown. The FDA recently announced the national recommendation for transition to duodenoscopes with disposable components. Methods We studied contamination of Pentax Medical duodenoscopes with disposable tips used for ERCP. Duodenoscopes were cleaned and disinfected following removal of the disposable tip. First, one manual wash was performed with detergent and brushes that fit into the suction channel, air/water valves, cylinder, and elevator chamber. Afterward, the duodenoscope underwent HLD with an automated endoscope re-processor. Our study evaluated the success of an abbreviated cycle of one MW followed by one HLD (MW-HLD) cycle compared to a pair of MW-HLD cycles. Each duodenoscope was sampled in 4 locations after the first MW-HLD cycle and the second: 1) The elevator tab, 2) elevator channel distal opening, 3) composite duodenoscope tip, and 4) the elevator channel (Figure 1). Samples 1-3 were collected with flocked swabs. Swabs were plated on routine medias for relevant enteric pathogens. The 4th was collected by flushing 25 mL of neutralizing buffer through the elevator channel, then scrubbing the channel with a brush, followed by another 25 mL flush. The 50 mL eluent was vacuum filtered through a 0.22-micron filter and plated on TSA. Antibiotic resistance was assessed via PCR. CFU and proportion of contaminated scopes were compared between MW-HLD cycles. Results 46 duodenoscopes were sampled from September 2021 through March 2022 resulting in 92 sample events and 368 total samples. After one MW-HLD cycle, 19 of 46 (41%) duodenoscopes remained contaminated, including 5 (11%) with VRE (Table 1). After two MW-HLD cycles, 11 (24%) remained contaminated and 0 (0%) with VRE (p=0.08, 0.02, respectively). Results were similar at the sample location level (p=0.03, 0.01, respectively). Proportion of duodenoscopes contaminated with any flora and Vancomycin-resistant Enterococcus spp. Conclusion Our data demonstrate that 1 MW-HLD cycle is insufficient at decontaminating duodenoscopes with disposable tips but do support the use of two MW-HLD cycles. VRE was identified after one MW- HLD cycle, but not after two MW-HLD cycles. Further studies are needed to determine the optimal combination of MWs and HLDs while minimizing HLD staff time. Disclosures All Authors: No reported disclosures.

Plasma-generated reactive water mist for disinfection of N95 respirators laden with MS2 and T4 bacteriophage viruses

Due to the shortage of personal protective equipment (PPE) during the COVID-19 pandemic, the interest and demand for sterilization devices to reuse PPE has increased. For reuse of face masks, they must be effectively decontaminated of potential infectious agents without compromising its filtration ability during sterilization. In this study, we utilized an atmospheric pressure pulsed dielectric barrier discharge (DBD), combined with nebulized liquid microdroplets to generate plasma-activated mist (PAM). MS2 and T4 bacteriophages were used to conduct the decontamination tests on two types of N95 respirators. Results showed at least a 2-log reduction of MS2 and T4 on N95 respirators treated in one cycle with 7.8% hydrogen peroxide PAM and at least a 3-log reduction treated in 10% hydrogen peroxide PAM. In addition, it was found that there was no significant degradation in filtration efficiency of N95 respirators (3M 1860 and 1804) treated in 10% hydrogen peroxide PAM found after 20 cycles. In terms of re-useability of masks after treatment as determined, it was shown that the elastic straps of 3M 1804 were fragmented after 20 treatment cycles rendering them unusable, while the straps of 3M 1860 were not negatively affected even after 20 disinfection cycles.

Microbiologically Pure Cotton Fabrics Treated with Tetrabutylammonium OXONE as Mild Disinfection Agent.

The microbiological purity of textiles plays a pivotal role in the use of textiles, especially in hospitals and other medical facilities. Microbiological purity of cotton fabric was achieved by a new disinfection method using tetrabutyloammonium OXONE (TBA-OXONE) before washing. As a result of the disinfection, the cotton fabric became microbiologically pure, despite the markedly decreased washing time with respect to the widely used standard procedure. Shortening of the washing time allowed for significant energy savings. In addition, the effect of the number of disinfection and washing cycles on the tensile properties and tearing force of the fabric was examined. After 120 disinfection and washing cycles the mechanical properties of cotton fabric were only slightly worsened.

Semiautomated disinfection of ophthalmic contact lenses.

The ophthalmic lenses that come in contact with the eyes pose a high risk for the transmission of bacterial and viral infections in eye clinics. Disinfecting these lenses does not happen stringently in a busy practice. We describe a novel method of disinfecting ophthalmic contact lenses using a semiautomated lens disinfector equipment, semiautomated lens disinfector. The equipment has motors to pump in and pump out water and disinfecting solution into a reservoir bath. The used ophthalmic lenses will be placed in a tray that partially dips into the bath for disinfection. Microbiology tests that were done to check the quality of the disinfection cycle showed good outcomes. Disinfection of ophthalmic contact lenses with the new equipment appeared to effectively eliminate contaminant microorganisms. This equipment can be used in busy ophthalmic clinics to alleviate the chances of cross-infection.

Cold plasma as a fast acting alternative disinfection method

Abstract Cold plasma disinfection is a cost-efficient and, above all, fast way of disinfecting even complex products. There are already approaches where plasma disinfection is used for wound treatment or hand disinfection. The ionization of a gas results in a number of physical and chemical processes that have a damaging effect on microorganisms. Especially in the field of medical device reprocessing, a tool that can reliably disinfect even very complex products in a short time would be a great asset. In this work, the potential of a newly developed cold plasma disinfection device was tested for the reduction of microbiological contamination and thus the disinfecting effect. In order to examine this microbiological reduction 3D printed scaffolds with contaminated test plates were used. This was done with different concentrations of the bacteria in the cold plasma disinfection process to determine the maximum germ reduction effect. In a first test run, the maximum effect of germ reduction was achieved with log 3.6. By making further changes and increasing the disinfection cycles, it was possible to increase the germ reduction to log 4.7. If these values are confirmed and can be improved by further modifications (e.g. increasing the plasma concentration), cold plasma technology represents a very good alternative to conventional disinfection methods.

Sono-photocatalytic disinfection of high strength multi-drug resistant Klebsiella pneumonia in presence of blue LED-active CdS nanorods

The prevalence of antibiotic resistant pathogenic microbes in wastewater necessitates effective disinfection treatment to protect human health and the environment. Klebsiella pneumoniae is considered as an opportunistic and emerging human pathogen which can develop resistance towards a broad range of antibiotics. In the present study, a hybrid approach merging photocatalysis by CdS nanorods (NRs) with physico-chemical method of acoustic cavitation was investigated to disinfect MDR Klebsiella pneumonia under blue LED irradiation. Various reaction parameters like light intensity, sonication power, catalyst loading, and bacterial load were studied. Effective and complete disinfection was observed with a catalyst loading of 250 mg/L eradicating a bacterial concentration of 106 CFU/mL within 20 mins. Being a hybrid strategy, the catalyst concentration below the optimum (<1xMIC) was also able to provide significant disinfection majorly due to the synergistic effect. Primary mechanism of disinfection was inferred from the escape of intracellular nucleic acids suggesting disruption of cell membrane followed by ROS scavenging experiments which suggested the importance of various ROS species in the decontamination experiments. The stability of photocatalytic efficiency of the CdS nanorods even after multiple cycles of disinfection revealed possibilities of nanomaterial recycling for wastewater disinfection. The results suggest that the hybrid sono-photocatalytic approach can proficiently eliminate harmful multi-drug resistant bacteria and drastically reduce operational time. However, upscaling of the approach to disinfect actual wastewater remains to be investigated for environmental applications.