Reduce Surface Contamination Research Articles

Meso-Structure Controlled Synthesis of Sodium Iron-Manganese Oxides Cathode for Low-Cost Na-Ion Batteries

A modified co-precipitation method is introduced to synthesize P2-type Na0.67Fe1/4Mn3/4O2 cathode for low-cost Na-ion batteries. The meso-structure of the obtained material is well controlled through regulated cooling after a high temperature calcination process. The material via slow-cooling consists of sphere-like secondary particles with a uniform dispersion while the quenched material exhibits a hexagonal plate-like primary particle without meso-structure. Meso-structure is found to have a distinct effect upon the electrochemical performance of P2-type layered cathode. The slow-cooled sample exhibits a larger capacity and improved cyclability compared with the quenched sample, which is attributed to the larger surface area, reduced surface contamination, and surprisingly higher transition metal redox activity. This work demonstrates that cooling rate plays the key role in controlling the formation of spherical meso-structure for sodium iron-manganese oxides with enhanced electrochemical performance.

Effects of different packaging materials coated with aloe vera extract on the microbial quality of african breadfruit flour (treculia africana) during storage

Antimicrobials in food packaging are used to enhance quality and safety by reducing surface contamination of processed food. This study investigated the effects of Aloe vera- coated packaging materials on the microbial quality characteristics of breadfruit flour. Breadfruit flour was packaged in Jute bag (JB), Kalico bag (KA), low-density Polyethylene-lined Brown paper (LDPEBP) and they were compared with control. Samples were analyzed for changes in microbiological (total colony count and total fungal count) and moisture content during a storage period of 12 weeks interval during storage at ambient temperature of 25 ± 2oC. Packaging significantly (p< 0.05) affected the moisture content and microbiological of breadfruit flour during storage. The moisture content, total colony count, and total fungi count significantly (p< 0.05) increased as the storage time increased. The sample packaged in Brown paper (BP) were more acceptable than those in other packaging materials.

Assessment of apolar lipids in subseafloor rocks and potential contaminants from the Atlantis Massif (IODP Expedition 357)

International Ocean Discovery Program Expedition 357 drilled 17 boreholes across the Atlantis Massif with the goals of investigating carbon cycling and the presence of life in a zone of active serpentinization. The expedition recovered multiple lithologies including gabbros, basalts, carbonate sands, and serpentinites. A subset of contrasting lithologies were analyzed for apolar lipid content to determine if non-volatile organic molecules can be detected in the oceanic subsurface. The definitive detection and identification of abiotic and biological lipids in the subsurface of an actively serpentinizing system would be a significant step towards understanding a variety of scientific processes, including the evolution of pre-biotic chemistry, microbial habitability, and the global carbon cycle. Given the high potential for contamination during drilling, a suite of materials used in sample collection and processing were also analyzed to characterize their signatures. An n-alkane series ranging from C18 to C30 with δ13C isotopic values of −30.9‰ to −28.8‰ was present in lithologically diverse samples. Multiple lines of evidence point to the rock saw used to remove core exteriors during sample processing as the source of these compounds. Many of the other sample-handling procedures designed to reduce surface contamination were determined to be effective and could be implemented in future projects. This result highlights the value of careful prevention and characterization of contamination to allow for more accurate interpretations of complex and dynamic subsurface processes, and the importance that future reports of these compounds occurs in conjunction with thorough contamination assessments.

Environmental effectiveness of pulsed-xenon light in the operating room

Manual cleaning and disinfection of the operating room (OR) environment may be inadequate due to human error. No-touch technologies, such as pulsed-xenon ultraviolet light (PX-UV), can be used as an adjunct to manual cleaning processes to reduce surface contamination in the OR. This article reports the cumulative results from 23 hospitals across the United States that performed microbiologic validation of PX-UV disinfection after manual cleaning. We obtained samples from 732 high-touch surfaces in 136 ORs at 23 hospitals, after manual terminal cleaning, and again after PX-UV disinfection (n = 1464 surface samples). Samples were enumerated after incubation, and the results are reported as total colony-forming units (CFU). The average CFU after manual cleaning ranged from 5.8 to 34.37, and after PX-UV, from 0.69 to 6.43. With manual cleaning alone, 67% of surfaces were still positive for CFUs; after PX-UV disinfection, that number decreased to 38% of all sampled surfaces-a 44% reduction. When comparing manual cleaning to PX-UV, the reduction in CFU count was statistically significant. When used after the manual cleaning process, the PX-UV device significantly reduced contamination on high-touch surfaces in the OR.

Contrasting Effects of Four Plant Residues on Phosphorus Sorption-Desorption in Some Phosphorus Fertilized Calcareous Soils

ABSTRACTFour types of plant residues (fruit waste, potato, sunflower, and wheat) with wide ranges of carbon to nitrogen (C/N) and carbon to phosphorus (C/P) ratios were added to the soil at the rate of 20 g kg−1 (dry weight basis) and incubated for two months. In soils treated with plant residues, the P sorption ranged from 62.0% (potato) to 96.6% (wheat) and from 12.6% (fruit waste) to 50.6% (wheat) when 20 and 1500 mg P kg−1 were added to the soils, respectively. In general, incorporation of plant residues decreased maximum P sorption capacity but increased bonding energy. The maximum P sorption capacity was reduced from 586 mg kg−1to 500, 542, and 548 by wheat, fruit, and potato residues, respectively, but increased to 665 mg kg−1 by sunflower residue. At higher P addition, the highest percentage of desorbed P was observed in soils treated with wheat residue (49.9%); followed by fruit waste (46.5%), potato (43.5%), sunflower (38.8%) and control soils (37.0%). It indicated that the P content of the organic residues had an important role in the sorption and desorption of P in calcareous soils. Among organic residues, sunflower residue showed high sorption and low desorption of P in soils, indicating a higher potential of this organic residue for P retention and reducing surface and groundwater contamination in calcareous soils.

Multicenter evaluation of a new closed system drug-transfer device in reducing surface contamination by antineoplastic hazardous drugs

Results of a study to evaluate the effectiveness of a recently introduced closed system drug-transfer device (CSTD) in reducing surface contamination during compounding and simulated administration of antineoplastic hazardous drugs (AHDs) are reported. Wipe samples were collected from 6 predetermined surfaces in compounding and infusion areas of 13 U.S. cancer centers to establish preexisting levels of surface contamination by 2 marker AHDs (cyclophosphamide and fluorouracil). Stainless steel templates were placed over the 6 previously sampled surfaces, and the marker drugs were compounded and infused per a specific protocol using all components of the CSTD. Wipe samples were collected from the templates after completion of tasks and analyzed for both marker AHDs. Aggregated results of wipe sampling to detect preexisting contamination at the 13 study sites showed that overall, 66.7% of samples (104 of 156) had detectable levels of at least 1 marker AHD; subsequent testing after CSTD use per protocol found a sample contamination rate of 5.8% (9 of 156 samples). In the administration areas alone, the rate of preexisting contamination was 78% (61 of 78 samples); with use of the CSTD protocol, the contamination rate was 2.6%. Twenty-six participants rated the CSTD for ease of use, with 100% indicating that they were satisfied or extremely satisfied. A study involving a rigorous protocol and 13 cancer centers across the United States demonstrated that the CSTD reduced surface contamination by cyclophosphamide and fluorouracil during compounding and simulated administration. Participants reported that the CSTD was easy to use.

Evaluation of hospital-grade disinfectants on viral deposition on surfaces after toilet flushing

Past studies have shown that infectious aerosols created during toilet flushing result in surface contamination of the restroom. The goals of this study were to quantify viral contamination of surfaces in restrooms after flushing and the impact of disinfectants added to the toilet bowl prior to flushing on reducing surface contamination. The degree of contamination of surfaces in the restroom was assessed with and without the addition of coliphage MS2 to the toilet bowl before flushing. The bowl water and various surfaces in the restroom were subsequently tested for the presence of the virus. The toilet bowl rim, toilet seat top, and toilet seat underside were contaminated in all trials without a disinfectant added to the bowl water before flushing. All disinfectants significantly reduced concentrations on surfaces when the contact time was ≥15 minutes. Hydrogen peroxide resulted in very little reduction of virus in the toilet bowl (<1 log10). Peracetic acid and quaternary ammonium had the greatest log reductions on virus in the organic matter in the toilet. Toilet flushing resulted in extensive contamination of surfaces within the restroom. Addition of disinfectant to the toilet bowl prior to flushing reduced the level of contamination in the bowl and fomites after flushing.

The potential of alcohol release doorplates to reduce surface contamination during hand contact

Optimal hand hygiene may be compromised by contact with contaminated environmental surfaces. To investigate the in-vitro efficacy of a novel alcohol-release doorplate to reduce surface contamination during hand contact. Prototype, horizontally held, Surfaceskins, alcohol gel-impregnated and control (aluminium) doorplates were challenged (N=72 per micro-organism) with Staphylococcus aureus-, Eschericia coli-, Enterococcus faecalis-, or Clostridium difficile-contaminated fingers. S.aureus and E.faecalis were used for challenges (90 per micro-organism) of vertical (modified design) doorplates, on days 0, 3, 4, 6, and 7. Surface contamination was measured pre and immediately post challenges using agar contact plates. Horizontal test, but not control, doorplates demonstrated bacterial killing of S.aureus, E.faecalis and E.coli, but not of C.difficile; hence, only testing of S.aureus and E.faecalis was continued. Vertical Surfaceskins, but not control, doorplates demonstrated rapid killing of S.aureus over seven days. There were significant reductions (>90% up to day 6; P≤0.01) of surface bacterial colony counts compared with controls immediately post challenge. There were also significant reductions in Surfaceskins doorplate enterococcal colony counts compared with controls on every day of testing (P≤0.004). There was no evidence that bacterial recovery was greater from the tops of Surfaceskins doorplates (i.e. due to pooling of contents). Surfaceskins doorplates were efficient at reducing surface contamination by S.aureus, E.faecalis, and E.coli. Reducing microbial contamination of frequently touched door surfaces, and so bacterial transfer via hands, could feasibly reduce the risk of healthcare-associated and other infections.

Abstract 4231: Significant reduction in workplace contamination of antineoplastic hazardous drugs in 13 U.S. hospitals following utilization of a new closed-system drug transfer device

Abstract Background: Adverse effects of worker exposure to antineoplastic hazardous drugs (AHD) have been well documented with dermal absorption from contaminated surfaces in the work environment being one of the most well researched sources of exposure. Multiple studies have documented decreased surface contamination when using CSTDs for AHD handling. Decreased surface contamination should result in decreased worker exposure and decreased risk of adverse effects. Purpose: The purpose of this study was to determine the effectiveness of a new CSTD in reducing surface contamination of marker AHDs cyclophosphamide (CP) and 5-fluorouracil (5FU) during compounding and administration in multiple cancer centers, using surface wipe-sampling methodology. The results of the wipe sampling were compared to existing contamination in the sites and to similar studies in peer-reviewed literature to determine relative effectiveness. Methods: Wipe samples of six predetermined surfaces were collected in designated compounding and infusion areas of 13 cancer centers to establish the preexisting level of surface contamination with two marker AHDs. Stainless steel templates of approximately 500 cm2 were placed over previously sampled surfaces, and a specific protocol of set doses of the AHDs were compounded and infused, using all of the components of the new CSTD system, over the templates. Wipe samples of the templates were collected following the completion of tasks and analyzed for both marker AHDs. Results: A total of 312 wipe samples were collected from the 13 centers, 156 at baseline and 156 with the CSTD. All samples were reported as ng/cm2 with the analytical limit of detection (LOD) for each drug being 0.002 ng/500 cm2. In the aggregate results of 13 sites sampled for existing contamination, 67% of wipe samples had detectable levels of the AHDs with a range of LOD to 19.880 ng/cm2 of 5FU and 0.648 ng/cm2 of CP. With the new CSTD the contaminated samples were reduced to 5.8% with a range LOD to 0.004ng/cm2 of 5FU and 2.60ng/cm2 of CP. Conclusions: The new CSTD significantly reduced surface contamination by the marker AHDs during both compounding and administration. Compared to published results of two multi-site studies of another CSTD for compounding, the new CSTD is superior in reducing surface contamination with marker AHDs, as determined by wipe sampling of similar surfaces. Research reported in this study was supported by the National Cancer Institute (NCI) of the National Institutes of Health (NIH) under award number 5R44CA153636. Citation Format: Timothy Tyler, Luci Power. Significant reduction in workplace contamination of antineoplastic hazardous drugs in 13 U.S. hospitals following utilization of a new closed-system drug transfer device [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4231. doi:10.1158/1538-7445.AM2017-4231

Prospective cluster controlled crossover trial to compare the impact of an improved hydrogen peroxide disinfectant and a quaternary ammonium-based disinfectant on surface contamination and health care outcomes

Quaternary ammonium-based (Quat) disinfectants are widely used, but they have disadvantages. This was a 12-month prospective cluster controlled crossover trial. On 4 wards, housekeepers performed daily cleaning using a disinfectant containing either 0.5% improved hydrogen peroxide (IHP) or Quat. Each month, 5-8 high-touch surfaces in several patient rooms on each ward were tagged with a fluorescent marker and cultured before and after cleaning. Hand hygiene compliance rates and antimicrobial usage on study wards were obtained from hospital records. Outcomes included aerobic colony counts (ACCs), percent of wiped surfaces yielding no growth after cleaning, and a composite outcome of incidence densities of nosocomial acquisition and infection caused by vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus, and Clostridium difficile infection. Statistical analysis was performed using χ2 test, Fisher exact test, Welch test, and logistic regression methods. Mean ACCs per surface after cleaning were significantly lower with IHP (14.0) than with Quat (22.2) (P = .003). The proportion of surfaces yielding no growth after cleaning was significantly greater with IHP (240/500; 48%) than with Quat (182/517; 35.2%) (P < .0001). Composite incidence density of nosocomial colonization or infection with IHP (8.0) was lower than with Quat (10.3) (incidence rate ratio, 0.77; P = .068; 95% confidence interval, 0.579-1.029). Compared with a Quat disinfectant, the IHP disinfectant significantly reduced surface contamination and reduced a composite colonization or infection outcome.

Ultralow friction of ink-jet printed graphene flakes.

We report the frictional response of few-layer graphene (FLG) flakes obtained by the liquid phase exfoliation (LPE) of pristine graphite. To this end, we inkjet print FLG on bare and hexamethyldisilazane-terminated SiO2 substrates, producing micrometric patterns with nanoscopic roughness that are investigated by atomic force microscopy. Normal force spectroscopy and atomically-resolved morphologies indicate reduced surface contamination by solvents after a vacuum annealing process. Notably, the printed FLG flakes show ultralow friction comparable to that of micromechanically exfoliated graphene flakes. Lubricity is retained on flakes with a lateral size of a few tens of nanometres, and with a thickness as small as ∼2 nm, confirming the high crystalline quality and low defects density in the FLG basal plane. Surface exposed step edges exhibit the highest friction values, representing the preferential sites for the origin of the secondary dissipative processes related to edge straining, wear or lateral displacement of the flakes. Our work demonstrates that LPE enables fundamental studies on graphene friction to the single-flake level. The capability to deliver ultralow-friction-graphene over technologically relevant substrates, using a scalable production route and a high-throughput, large-area printing technique, may also open up new opportunities in the lubrication of micro- and nano-electromechanical systems.

Effectiveness of a Closed-System Transfer Device in Reducing Surface Contamination in a New Antineoplastic Drug-Compounding Unit: A Prospective, Controlled, Parallel Study

BackgroundThe objective of this randomized, prospective and controlled study was to investigate the ability of a closed-system transfer device (CSTD; BD-Phaseal) to reduce the occupational exposure of two isolators to 10 cytotoxic drugs and compare to standard compounding devices.Methods and FindingsThe 6-month study started with the opening of a new compounding unit. Two isolators were set up with 2 workstations each, one to compound with standard devices (needles and spikes) and the other using the Phaseal system. Drugs were alternatively compounded in each isolator. Sampling involved wiping three surfaces (gloves, window, worktop), before and after a cleaning process. Exposure to ten antineoplastic drugs (cyclophosphamide, ifosfamide, dacarbazine, 5-FU, methotrexate, gemcitabine, cytarabine, irinotecan, doxorubicine and ganciclovir) was assessed on wipes by LC-MS/MS analysis. Contamination rates were compared using a Chi2 test and drug amounts by a Mann-Whitney test. Significance was defined for p<0.05. Overall contamination was lower in the “Phaseal” isolator than in the “Standard” isolator (12.24% vs. 26.39%; p < 0.0001) although it differed according to drug. Indeed, the contamination rates of gemcitabine were 49.3 and 43.4% (NS) for the Standard and Phaseal isolators, respectively, whereas for ganciclovir, they were 54.2 and 2.8% (p<0.0001). Gemcitabine amounts were 220.6 and 283.6 ng for the Standard and Phaseal isolators (NS), and ganciclovir amounts were 179.9 and 2.4 ng (p<0.0001).ConclusionThis study confirms that using a CSTD may significantly decrease the chemical contamination of barrier isolators compared to standard devices for some drugs, although it does not eliminate contamination totally.

Effectiveness of ultraviolet devices and hydrogen peroxide systems for terminal room decontamination: Focus on clinical trials.

Over the last decade, substantial scientific evidence has accumulated that indicates contamination of environmental surfaces in hospital rooms plays an important role in the transmission of key health care–associated pathogens (eg, methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Clostridium difficile, Acinetobacter spp). For example, a patient admitted to a room previously occupied by a patient colonized or infected with one of these pathogens has a higher risk for acquiring one of these pathogens than a patient admitted to a room whose previous occupant was not colonized or infected. This risk is not surprising because multiple studies have demonstrated that surfaces in hospital rooms are poorly cleaned during terminal cleaning. To reduce surface contamination after terminal cleaning, no touch methods of room disinfection have been developed. This article will review the no touch methods, ultraviolet light devices, and hydrogen peroxide systems, with a focus on clinical trials which have used patient colonization or infection as an outcome.Multiple studies have demonstrated that ultraviolet light devices and hydrogen peroxide systems have been shown to inactivate microbes experimentally plated on carrier materials and placed in hospital rooms and to decontaminate surfaces in hospital rooms naturally contaminated with multidrug-resistant pathogens. A growing number of clinical studies have demonstrated that ultraviolet devices and hydrogen peroxide systems when used for terminal disinfection can reduce colonization or health care–associated infections in patients admitted to these hospital rooms.

Efficacy of two hydrogen peroxide vapour aerial decontamination systems for enhanced disinfection of meticillin-resistant Staphylococcus aureus, Klebsiella pneumoniae and Clostridium difficile in single isolation rooms

Hydrogen peroxide vapour (HPV) disinfection systems are being used to reduce patients' exposure to hospital pathogens in the environment. HPV whole-room aerial disinfection systems may vary in terms of operating concentration and mode of delivery. To assess the efficacy of two HPV systems (HPS1 and HPS2) for whole-room aerial disinfection of single isolation rooms (SIRs). Ten SIRs were selected for manual terminal disinfection after patient discharge. Test coupons seeded with biological indicator (BI) organisms [∼10(6) colony-forming units (cfu) of meticillin-resistant Staphylococcus aureus (MRSA) or Klebsiella pneumoniae, or ∼10(5)cfu Clostridium difficile 027 spores] prepared in a soil challenge were placed at five locations per room. For each cycle, 22 high-frequency-touch surfaces in SIRs were sampled with contact plates (∼25cm(2)) before and after HPV decontamination, and BIs were assayed for the persistence of pathogens. Approximately 95% of 214 sites were contaminated with bacteria after manual terminal disinfection, with high numbers present on the SIR floor (238.0-352.5cfu), bed control panel (24.0-33.5cfu), and nurse call button (21.5-7.0cfu). Enhanced disinfection using HPV reduced surface contamination to low levels: HPS1 [0.25cfu, interquartile range (IQR) 0-1.13] and HPS2 (0.5cfu, IQR 0-2.0). Both systems demonstrated similar turnaround times (∼2-2.5h), and no differences were observed in the efficacy of the two systems against BIs (C.difficile ∼5.1log10 reduction; MRSA/K.pneumoniae ∼6.3log10 reduction). Despite different operating concentrations of hydrogen peroxide, MRSA persisted on 27% of coupons after HPV decontamination. Enhanced disinfection with HPV reduces surface contamination left by manual terminal cleaning, minimizing the risks of cross-contamination. The starting concentration and mode of delivery of hydrogen peroxide may not improve the efficacy of decontamination in practice, and therefore the choice of HPV system may be based upon other considerations such as cost, convenience and logistics.

Effects of Plant-Derived Extracts, Other Antimicrobials, and Their Combinations against Escherichia coli O157:H7 in Beef Systems

The antimicrobial effects of thyme oil (TO), grapefruit seed extract (GSE), and basil essential oil, alone or in combination with cetylpyridinium chloride (CPC), sodium diacetate, or lactic acid, were evaluated against Escherichia coli O157:H7 in a moisture-enhanced beef model system. The model system was composed of a nonsterile beef homogenate to which NaCl (0.5%) and sodium tripolyphosphate (0.25%) were added, together with the tested antimicrobial ingredients. Beef homogenate treatments were inoculated (ca. 3 log CFU/ml) with rifampin-resistant E. coli O157:H7 (eight-strain mixture) and incubated at 15°C (48 h). The most effective individual treatments were TO (0.25 or 0.5%) and GSE (0.5 or 1.0%), which immediately reduced (P < 0.05) pathogen levels by ≥3.4 log CFU/ml. Additionally, CPC (0.04%) reduced initial E. coli O157:H7 counts by 2.7 log CFU/ml. Most combinations of the tested plant-derived extracts with CPC (0.02 or 0.04%) and sodium diacetate (0.25%) had an additive effect with respect to antibacterial activity. In a second study, antimicrobial interventions were evaluated for their efficacy in reducing surface contamination of E. coli O157:H7 on beef cuts and to determine the effect of these surface treatments on subsequent internalization of the pathogen during blade tenderization. Beef cuts (10 by 8 by 3.5 cm) were inoculated (ca. 4 log CFU/g) on one side with the rifampin-resistant E. coli O157:H7 strain mixture and were then spray treated (20 lb/in2, 10 s) with water, GSE (5 and 10%), lactic acid (5%), or CPC (5%). Untreated (control) and spray-treated surfaces were then subjected to double-pass blade tenderization. Surface contamination (4.4 log CFU/g) of E. coli O157:H7 was reduced (P < 0.05) to 3.4 (5% CPC) to 4.1 (water or 5% GSE) log CFU/g following spray treatment. The highest and lowest transfer rates of pathogen cells from the surface to deeper tissues of blade-tenderized sections were obtained in the untreated control and CPC-treated samples, respectively.

Sanitizer applicability in a laboratory model strawberry hydrocooling system

After harvest, strawberries are cooled to 2–5°C, typically by forced-air cooling. Hydrocooling is an alternative method that ensures faster cooling and with the addition of various sanitizers can reduce the risk of microbial cross contamination. In this study, the effect of forced-air cooling and hydrocooling on the survival of Lactobacillus plantarum, a non-pathogenic, potential surrogate bacterium, was evaluated. Further, the efficacy of three antimicrobial compounds, sodium hypochlorite (HOCl, 100μL/L), aqueous chlorine dioxide (ClO2, 5μL/L) and peroxyacetic acid (PAA, 80μL/L) in reducing Lactobacillus levels during strawberry hydrocooling was also investigated. The results indicated that the Lactobacillus population on forced-air cooled strawberries was not significantly different from untreated strawberries. Compared to forced-air cooling, hydrocooling significantly reduced Lactobacillus survival on inoculated intact strawberries, even in the absence of a sanitizer. The addition of ClO2 resulted in the least reduction in initial Lactobacillus levels (∼1logCFU/mL), similar to those on strawberries hydrocooled without antimicrobials. The addition of HOCl or PAA to the hydrocooling water resulted in respective reductions of 2.5logCFU/mL and 4.0CFU/mL in the initial Lactobacillus levels, which continued to decrease throughout the sampling period. The results from this study indicate that antimicrobials HOCl and PAA are both effective in reducing surface contamination on strawberries during hydrocooling.

Surface Micropattern Resists Bacterial Contamination Transferred by Healthcare Practitioners

Environmental contamination contributes to an estimated 20-40% of all hospital- acquired infections (HAI). Infection control practices continue to improve, but multipronged approaches are necessary to fully combat the diversity of nosocomial pathogens and emerging multidrug resistant organisms. The Sharklet™ micropattern, inspired from the microtopography of shark skin, was recently shown to significantly reduce surface contamination but has not been evaluated in a clinical setting. The focus of this study was the transfer of bacteria onto micropatterned surfaces compared to unpatterned surfaces in a clinical simulation environment involving healthcare practitioners. Physician volunteers were recruited to participate in an emergency medicine scenario involving a contact-precaution patient with an acute pulmonary embolism. Prior to scenario initiation, Staphylococcus aureus was inoculated onto the leg of a simulation mannequin and fresh micropatterned and unpatterned surface films were placed on a code cart, cardiac defibrillator shock button, and epinephrine medication vial. Six physicians interacted with micropatterned surfaces and five physicians interacted with unpatterned surfaces in separate scenarios. Bacterial load loss from the first contact location (control film over the femoral pulse) to subsequent unpatterned or micropatterned surface test locations was quantified as a log reduction (LR) for each surface type. The code cart, cardiac defibrillator button, and medication vial locations with micropatterned surfaces resulted in LRs that were larger than the unpatterned LRs by 0.64 (p=0.146), 1.14 (p=0.023), and 0.58 (p=0.083) respectively for each location. The geometric mean CFU/RODAC at the first control surface touched at the femoral pulse pads ranged from 175-250 CFU/RODAC (95% confidence interval). Thus, the micropatterned LRs were consistently greater than the unpatterned LRs, substantiating the micropattern-dependent reduction of microorganism transfer. Principal component analysis showed that the LRs for the code cart and the cardiac defibrillator button highly covaried. Thus, a single mean LR was calculated from these two locations for each surface type; 5.4 times more bacteria attached to the unpatterned surfaces compared to the micropatterned surfaces (p = 0.058). The simulated clinical scenario involving healthcare practitioners demonstrated that the micropatterned surface reduced the transfer of bacterial contamination based on the larger LRs for the micropatterned surface compared to control surfaces. Further investigation in hospital rooms where patients are receiving care will ultimately reveal the capability of micropatterned surfaces to minimize the incidence of HAIs.

Surface micropattern limits bacterial contamination.

BackgroundBacterial surface contamination contributes to transmission of nosocomial infections. Chemical cleansers used to control surface contamination are often toxic and incorrectly implemented. Additional non-toxic strategies should be combined with regular cleanings to mitigate risks of human error and further decrease rates of nosocomial infections. The Sharklet micropattern (MP), inspired by shark skin, is an effective tool for reducing bacterial load on surfaces without toxic additives. The studies presented here were carried out to investigate the MP surfaces capability to reduce colonization of methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) compared to smooth control surfaces.MethodsThe MP and smooth surfaces produced in acrylic film were compared for remaining bacterial contamination and colonization following inoculation. Direct sampling of surfaces was carried out after inoculation by immersion, spray, and/or touch methods. Ultimately, a combination assay was developed to assess bacterial contamination after touch transfer inoculation combined with drying (persistence) to mimic common environmental contamination scenarios in the clinic or hospital environment. The combination transfer and persistence assay was then used to test antimicrobial copper beside the MP for the ability to reduce MSSA and MRSA challenge.ResultsThe MP reduced bacterial contamination with log reductions ranging from 87-99% (LR = 0.90-2.18; p < 0.05) compared to smooth control surfaces. The MP was more effective than the 99.9% pure copper alloy C11000 at reducing surface contamination of S. aureus (MSSA and MRSA) through transfer and persistence of bacteria. The MP reduced MSSA by as much as 97% (LR = 1.54; p < 0.01) and MRSA by as much as 94% (LR = 1.26; p < 0.005) compared to smooth controls. Antimicrobial copper had no significant effect on MSSA contamination, but reduced MRSA contamination by 80% (LR = 0.70; p < 0.005).ConclusionThe assays developed in this study mimic hospital environmental contamination events to demonstrate the performance of a MP to limit contamination under multiple conditions. Antimicrobial copper has been implemented in hospital room studies to evaluate its impact on nosocomial infections and a decrease in HAI rate was shown. Similar implementation of the MP has potential to reduce the incidence of HAIs although future clinical studies will be necessary to validate the MP’s true impact.

Influence of microwave plasma pre-treatments of TiO2 electrodes on dye-sensitised solar cell efficiencies

The use of ozone and other pre-treatments of TiO2 photo-electrodes has become an important process step used to increase the efficiency of dye-sensitised solar cells (DSSCs). These pre-treatments are applied to reduce surface contamination and defects in order to improve current density, open circuit voltage and the overall efficiency of DSSCs. This study evaluates the scope of using low pressure microwave (MW) plasma pre-treatments of nanocrystalline TiO2 electrode layers as an alternative pre-treatment method to be applied prior to the dye adsorption step and evaluates the DSSC fabricated using such electrodes. Compared to control cells, (which had not been plasma treated), the power conversion efficiencies of the MW oxygen plasma treated cells exhibited significant improvement, for example up to 23% higher values.When comparing the 30sMW plasma pre-treatment with a 20min, UV-O3 treatment of TiO2 photo-electrodes, the former showed an increase of maximum power density by 23.5% compared to the 14.4% exhibited by the latter. Even though MW plasma treatment is carried out under low pressure (750Pa) compared to the atmospheric pressure UV-O3 treatments, the MW plasma treatment has the additional advantage of a shorter treatment time requiring only 30s instead of the 20min needed for the UV-O3 treatment. The observed improvement in cell efficiencies were shown to have a strong correlation with a decrease in the concentration of oxygen vacancy related Ti3+ defects in TiO2. The cell efficiency decreased with an increase in Ti3+ defects as Ti3+ defects serve as charge recombination centres for back electron transfer pathways. A decrease in Ti3+ concentration also increases the level of dye adsorption as the sensitizers are anchored via Ti4+, again paving the way for improved light harvest and an enhancement in the cell output. These results indicate that the MW plasma treatment represents an alternative rapid method for the pre-treatment of TiO2 photo-electrodes prior to dye adsorption in DSSC manufacturing.

Increased hand washing reduces influenza virus surface contamination in Bangkok households, 2009–2010

Within a hand-washing clinical trial, we evaluated factors associated with fomite contamination in households with an influenza-infected child. Influenza virus RNA contamination was higher in households with low absolute humidity and in control households, suggesting that hand washing reduces surface contamination.