Impact of egg disinfection of hatching eggs on the eggshell microbiome and bacterial load

DEFF Research Database (Denmark)

Olsen, R.; Kudirkiene, E.; Thofner, I.

2017-01-01

Disinfection of hatching eggs is essential to ensure high quality production of broilers. Different protocols are followed in different hatcheries; however, only limited scientific evidence on how the disinfection procedures impact the microbiome is available. The aim of the present study...... was to characterize the microbiome and aerobic bacterial load of hatching eggs before disinfection and during the subsequent disinfection steps. The study included a group of visibly clean and a group of visibly dirty eggs. For dirty eggs, an initial wash in chlorine was performed, hereafter all eggs were submitted...... to two times fumigation and finally spray disinfection. The eggshell microbiome was characterized by sequencing of the total amount of 16S rRNA extracted from each sample, consisting of shell surface swabs of five eggs from the same group. In addition, the number of colony forming units (cfu) under...

Electrochemical study of AISI 304 stainless steel during the exposure at the disinfectant solutions with fungal suspensions

Energy Technology Data Exchange (ETDEWEB)

Stoica, M.; Bruma, M. [Department of Biochemistry and Technologies, Faculty of Food Science and Engineering, ' ' Dunarea de Jos' ' University of Galati, 111 Domneasca Street, 800201 Galati (Romania); Carac, G. [Department of Chemistry, Faculty of Sciences, ' ' Dunarea de Jos' ' University of Galati, 47 Domneasca Street, 800008 Galati (Romania)

2010-12-15

The effect of fungal suspensions on the disinfectant solution (Actisept with sodium dichloroisocyanurate as active substance, which releases 140 ppm active chlorine) and the corrosion behavior of type AISI 304 stainless steel (SS) were evaluated through linear polarization. The work presents a study of biocide Actisept solution as reference solution and the mixed solutions: reference biocide Actisept solution with three fungal suspensions (10 vol%), Aspergillus niger, Candida mycoderma, and Saccharomyces cerevisiae. The fungal suspension has an important influence on the synergistic effect of the SS corrosion in the following order: Saccharomyces cerevisiae > Candida mycoderma > Aspergillus niger. The E{sub corr} values from the mixed solutions decreased with immersion time of the samples. In the case of Aspergillus niger, the corrosion rate was lower than that of any other type of fungal suspension tested, because the arrangement in solutions, the size and composition of Aspergillus niger spores were more favorable to protect the spores of the chemical and the electrical stressing. The results showed that there is a synergistic effect between the active substances from the disinfectant, fungal suspensions and applied potential, thus this effect can be taken into consideration for the hygienic and safety food industry. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

An environmental disinfection odyssey: evaluation of sequential interventions to improve disinfection of Clostridium difficile isolation rooms.

Science.gov (United States)

Sitzlar, Brett; Deshpande, Abhishek; Fertelli, Dennis; Kundrapu, Sirisha; Sethi, Ajay K; Donskey, Curtis J

2013-05-01

OBJECTIVE. Effective disinfection of hospital rooms after discharge of patients with Clostridium difficile infection (CDI) is necessary to prevent transmission. We evaluated the impact of sequential cleaning and disinfection interventions by culturing high-touch surfaces in CDI rooms after cleaning. DESIGN. Prospective intervention. SETTING. A Veterans Affairs hospital. INTERVENTIONS. During a 21-month period, 3 sequential tiered interventions were implemented: (1) fluorescent markers to provide monitoring and feedback on thoroughness of cleaning facility-wide, (2) addition of an automated ultraviolet radiation device for adjunctive disinfection of CDI rooms, and (3) enhanced standard disinfection of CDI rooms, including a dedicated daily disinfection team and implementation of a process requiring supervisory assessment and clearance of terminally cleaned CDI rooms. To determine the impact of the interventions, cultures were obtained from CDI rooms after cleaning and disinfection. RESULTS. The fluorescent marker intervention improved the thoroughness of cleaning of high-touch surfaces (from 47% to 81% marker removal; P disinfection, whereas during interventions periods 1, 2, and 3 the percentages of CDI rooms with positive cultures after disinfection were reduced to 57%, 35%, and 7%, respectively. CONCLUSIONS. An intervention that included formation of a dedicated daily disinfection team and implementation of a standardized process for clearing CDI rooms achieved consistent CDI room disinfection. Culturing of CDI rooms provides a valuable tool to drive improvements in environmental disinfection.

Microbial contamination of disinfectant solutions in some health care ...

African Journals Online (AJOL)

Commonly used disinfectants in some health institutions in three major towns of northern Nigeria were examined for presence of bacteria contamination. For each disinfectant, stock, freshly diluted and left-over of used diluted samples were analyzed. All the stock samples were free of bacteria contaminants while 52.17% of ...

Comparison of the efficacy of a hydrogen peroxide dry-mist disinfection system and sodium hypochlorite solution for eradication of Clostridium difficile spores.

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Barbut, F; Menuet, D; Verachten, M; Girou, E

2009-06-01

To compare a hydrogen peroxide dry-mist system and a 0.5% hypochlorite solution with respect to their ability to disinfect Clostridium difficile-contaminated surfaces in vitro and in situ. Prospective, randomized, before-after trial. Two French hospitals affected by C. difficile. In situ efficacy of disinfectants was assessed in rooms that had housed patients with C. difficile infection. A prospective study was performed at 2 hospitals that involved randomization of disinfection processes. When a patient with C. difficile infection was discharged, environmental contamination in the patient's room was evaluated before and after disinfection. Environmental surfaces were sampled for C. difficile by use of moistened swabs; swab samples were cultured on selective plates and in broth. Both disinfectants were tested in vitro with a spore-carrier test; in this test, 2 types of material, vinyl polychloride (representative of the room's floor) and laminate (representative of the room's furniture), were experimentally contaminated with spores from 3 C. difficile strains, including the epidemic clone ribotype 027-North American pulsed-field gel electrophoresis type 1. There were 748 surface samples collected (360 from rooms treated with hydrogen peroxide and 388 from rooms treated with hypochlorite). Before disinfection, 46 (24%) of 194 samples obtained in the rooms randomized to hypochlorite treatment and 34 (19%) of 180 samples obtained in the rooms randomized to hydrogen peroxide treatment showed environmental contamination. After disinfection, 23 (12%) of 194 samples from hypochlorite-treated rooms and 4 (2%) of 180 samples from hydrogen peroxide treated rooms showed environmental contamination, a decrease in contamination of 50% after hypochlorite decontamination and 91% after hydrogen peroxide decontamination (P disinfection system is significantly more effective than 0.5% sodium hypochlorite solution at eradicating C. difficile spores and might represent a new

[Disinfection efficacy of hand hygiene based on chlorhexidine gluconate content and usage of alcohol-based hand-rubbing solution].

Science.gov (United States)

Tanaka, Ippei; Watanabe, Kiyoshi; Nakaminami, Hidemasa; Azuma, Chihiro; Noguchi, Norihisa

2014-01-01

Recently, the procedure for surgical hand hygiene has been switching to a two-stage method and hand-rubbing method from the traditional hand-scrubbing method. Both the two-stage and hand-rubbing methods use alcohol-based hand-rubbing after hand washing. The former requires 5 min of antiseptic hand washing, and the latter 1 min of nonantiseptic hand washing. For a prolonged bactericidal effect in terms of surgical hand hygiene, chlorhexidine gluconate (CHG) has been noted due to its residual activity. However, no detailed study comparing the disinfection efficacy and prolonged effects according to different contents of CHG and the usage of alcohol-based hand-rubbing has been conducted. The glove juice method is able to evaluate disinfection efficacy and prolonged effects of the disinfectants more accurately because it can collect not only transitory bacteria but also normal inhabitants on hands. In the present study, we examined the disinfection efficacy and prolonged effects on alcohol-based hand-rubbing containing CHG by six hand-rubbing methods and three two-stage methods using the glove juice method. In both methods, 3 mL (one pump dispenser push volume) alcohol-based hand-rubbing solution containing 1% (w/v) CHG showed the highest disinfection efficacy and prolonged effects, and no significant difference was found between the hand-rubbing and two-stage methods. In the two methods of hand hygiene, the hand-rubbing method was able to save time and cost. Therefore, the data strongly suggest that the hand-rubbing method using a one pump dispenser push volume of alcohol-based hand-rubbing solution containing 1% (w/v) CHG is suitable for surgical hand hygiene.

[Hydrogen peroxide, chloramine T and chlorhexidrine in the disinfection of acrylic resin].

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Czerwińska, W; Kedzia, A; Kałowski, M

1978-01-01

The effectiveness of 3% h drogen peroxide, 5% chloramine T and 0,5% chlorhexidine gluconate solutions in disinfection of acrylic resine plates massively infected with oral flora was analysed. The acrylic resine plates used for investigations, were infected in vitro with mixed salivary flora characterized by small numbers of yeast-like fungi (1st group), or great number of these microorganisms (2nd group). Infected plates were exposed to solutions of analysed disinfectants during various time periods. After rinsing or inactivation of disinfectant residues, acrylic plates were put into bacteriological medium and incubated during 7 days period in 37 degrees C. The results of this study indicated the effectiveness of acrylic plates disinfection to be dependent on used disinfectant, time of exposition, and microorganisms present on the surface of acrylic resine. The solutions of disinfectants were less active in the cases of plates infected with material containing great numbers of yeast-like microorganisms. Among analysed disinfectants 0,5% solution of chlorhexidine was characterized by most effective and rapid activity, whereas 3% solution of hydrogen peroxide was found to be the least effective.

Effect of different types of disinfection solution and aging on the hardness and colour stability of maxillofacial silicone elastomers.

Science.gov (United States)

Cevik, Pinar; Yildirim-Bicer, Arzu Z

2017-11-09

Understanding the effect of aging and different disinfecting agents on the physical properties of pigmented maxillofacial silicones may help eliminate the current uncertainty as to the best follow-up suggestions for the patients treated with silicone prostheses. One hundred fifty specimens (14 × 2 mm) were evaluated for colour and 75 specimens (30 × 10 mm) for hardness (total, 225 specimens). Five specimens were used for hardness testing in each disinfecting solution while 10 silicone specimens were used for colour evaluation. The samples were separated into 5 groups and the initial hardness and colour evaluations were performed and placed in disinfectant solution (neutral soap, effervescent tablet, 0.2% chlorhexidine, 4% chlorhexidine, sodium hypochlorite). A second set of colour and hardness measurements was taken after 48 hours of disinfection and 1,008 hours of artificial aging in a QUV-accelerated weathering tester. Two-way and 1-way analysis of variance with Tukey tests and paired t-test were used for statistical analysis (α = 0.05). Before artificial aging, the hardness value of the red pigment group was found to be significantly lower than that of the brown pigment group. After aging, the lowest Shore A value was seen in the neutral soap group, while the highest was seen in the effervescent tablet. Based on the results of this study, chlorohexidine 0.2% was found to be most suitable agent for disinfection of the prostheses. Washing with neutral soap caused loss of pigment from the surface of the silicones. Sodium hypochlorite was found to have a colour-fading effect on silicone specimens.

Aggregation of Adenovirus 2 in Source Water and Impacts on Disinfection by Chlorine

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Cromeans, Theresa L.; Metcalfe, Maureen G.; Humphrey, Charles D.; Hill, Vincent R.

2016-01-01

It is generally accepted that viral particles in source water are likely to be found as aggregates attached to other particles. For this reason, it is important to investigate the disinfection efficacy of chlorine on aggregated viruses. A method to produce adenovirus particle aggregation was developed for this study. Negative stain electron microscopy was used to measure aggregation before and after addition of virus particles to surface water at different pH and specific conductance levels. The impact of aggregation on the efficacy of chlorine disinfection was also examined. Disinfection experiments with human adenovirus 2 (HAdV2) in source water were conducted using 0.2 mg/L free chlorine at 5 °C. Aggregation of HAdV2 in source water (≥3 aggregated particles) remained higher at higher specific conductance and pH levels. However, aggregation was highly variable, with the percentage of particles present in aggregates ranging from 43 to 71 %. Upon addition into source water, the aggregation percentage dropped dramatically. On average, chlorination CT values (chlorine concentration in mg/L × time in min) for 3-log10 inactivation of aggregated HAdV2 were up to three times higher than those for dispersed HAdV2, indicating that aggregation reduced the disinfection rate. This information can be used by water utilities and regulators to guide decision making regarding disinfection of viruses in water. PMID:26910058

Influence of disinfectant solutions on the tensile bond strength of a fourth generation dentin bonding agent

Directory of Open Access Journals (Sweden)

BOCANGEL Jorge Saldivar

2000-01-01

Full Text Available The purpose of the present study was to evaluate the influence of different disinfectant solutions on the tensile bond strength of a fourth generation dentin bonding agent. Forty non carious human molars were selected. Teeth were embedded in acrylic resin and ground until the exposure of a flat superficial dentin surface. Teeth were randomly divided in 4 groups and treated as follows: Group 1 - 2.5% NaOCl for 40 seconds; Group 2 - 2% chlorhexidine for 40 seconds; Group 3 - 1.23% acidulated fluoride for 4 minutes; and Group 4 - control (without disinfectant solution. Following treatments, Scotchbond Multipurpose Plus® (3M was used according to the manufacturer's instructions. After that, the test specimens were built with composite resin (Z100®-3M, using a standard Teflon matrix. The specimens were stored in distilled water for 24 hours at a temperature of 37ºC. The tensile strength test was performed using a Mini Instrom testing machine. The mean values obtained for each group, in MPa, were: Group 1 - 7.37 (± 2.51; Group 2 - 11.25 (± 4.65; Group 3 - 9.80 (± 3.11; and Group 4 - 10.96 (± 3.37. The results were submitted to statistical analysis using the ANOVA test, and no statistical significant differences among the groups were found. It can be concluded that the different disinfectant substances used in this research do not adversely affect dentin adhesion.

Poorly processed reusable surface disinfection tissue dispensers may be a source of infection.

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Kampf, Günter; Degenhardt, Stina; Lackner, Sibylle; Jesse, Katrin; von Baum, Heike; Ostermeyer, Christiane

2014-01-21

Reusable surface disinfectant tissue dispensers are used in hospitals in many countries because they allow immediate access to pre-soaked tissues for targeted surface decontamination. On the other hand disinfectant solutions with some active ingredients may get contaminated and cause outbreaks. We determined the frequency of contaminated surface disinfectant solutions in reusable dispensers and the ability of isolates to multiply in different formulations. Reusable tissue dispensers with different surface disinfectants were randomly collected from healthcare facilities. Solutions were investigated for bacterial contamination. The efficacy of two surface disinfectants was determined in suspension tests against two isolated species directly from a contaminated solution or after 5 passages without selection pressure in triplicate. Freshly prepared use solutions were contaminated to determine survival of isolates. 66 dispensers containing disinfectant solutions with surface-active ingredients were collected in 15 healthcare facilities. 28 dispensers from nine healthcare facilities were contaminated with approximately 107 cells per mL of Achromobacter species 3 (9 hospitals), Achromobacter xylosoxidans or Serratia marcescens (1 hospital each). In none of the hospitals dispenser processing had been adequately performed. Isolates regained susceptibility to the disinfectants after five passages without selection pressure but were still able to multiply in different formulations from different manufacturers at room temperature within 7 days. Neglecting adequate processing of surface disinfectant dispensers has contributed to frequent and heavy contamination of use-solutions based on surface active ingredients. Tissue dispenser processing should be taken seriously in clinical practice.

Activity and action screening of selected disinfectants

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Kateřina Balharová

2006-01-01

Full Text Available This research work is aimed to monitoring of selected disinfectants´activity in operational conditions. Hereby there have been monitored two acidic disinfectants Despon K and Mikasan D, which have had-by their producer-stated different recommended concentration. These solutions were monitored in viewpoint of their activity at different temperature, time of circulation, pH and water hardness. In this work there were measured pH of solutions in unloaded medium to be compared with pH of solutions in loaded medium and this measuring was carried out regularly each week within a one month period. During this period there was also monitored total plate count (TPC, which was stated in the dairy, where samples were taken two-times monthly. It has been found, that the disinfectants Mikasan D and Mikal 94D are effective even by high water hardness.

Clinical evaluation of a new multi-purpose disinfecting solution in symptomatic wearers of silicone hydrogel contact lenses

Directory of Open Access Journals (Sweden)

Corbin GS

2012-07-01

Full Text Available Glenn S Corbin,1 David L Kading,2 Sean M Powell,3 Brian D Rosenblatt,4 Glenda B Secor,5 Cecile A Maissa,6 Renee J Garofalo71Wyomissing Optometric Center, Wyomissing, PA, USA; 2Specialty Eyecare Group, Kirkland, WA, USA; 320/20 Eye Care LLC, Lenexa, KS, USA; 4Rosenblatt Family Eye Care Associates, Raritan, NJ, USA; 5Huntington Beach, CA, USA; 6OTG Research and Consultancy, London, UK; 7Alcon Research Ltd, Fort Worth, TX, USABackground: The purpose of this study was to evaluate the safety and efficacy of a new multi-purpose disinfecting solution containing a diblock copolymer, poly(oxyethylene-poly(oxybutylene, designed to improve the wetting properties of silicone hydrogel lenses in patients with symptoms of discomfort.Methods: This 30-day, randomized, concurrently controlled, double-masked, multi-site study involved 589 subjects at 42 investigational sites in the US. Existing symptomatic lens wearers were randomly assigned to either regimen 1 (OPTI-FREE® PureMoist®, Alcon Laboratories Inc, a newly developed formulation containing the diblock copolymer, or regimen 2 (renu® fresh™ multi-purpose solution Bausch + Lomb, Inc. On days 0, 14 and 30, subjects assessed acceptability and comfort using seven Likert-type questions, rated the intensity of ocular symptoms (comfort, dryness, irritation, scratchiness, burning, stinging on a visual analog scale (0–100, as well as reported lens wearing time, comfortable lens wearing time, and rewetting drop frequency. The investigators assessed slit-lamp findings (including circumlimbal conjunctival lissamine green staining and corneal fluorescein staining, on-eye lens surface wettability and deposits, visual acuity, and adverse events.Results: Differences favoring regimen 1 were noted on Day 30 for the primary Likert statement “I can comfortably wear my lenses” (P = 0.047 and for comfortable lens wear time (P = 0.041. Symptoms of ocular scratchiness, ocular burning, and ocular stinging were all rated

Electrochemical disinfection of bacteria-laden water using antimony-doped tin-tungsten-oxide electrodes.

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Ghasemian, Saloumeh; Asadishad, Bahareh; Omanovic, Sasha; Tufenkji, Nathalie

2017-12-01

Electrochemical disinfection has been shown to be an efficient method with a shortrequired contact time for treatment of drinking water supplies, industrial raw water supplies, liquid foodstuffs, and wastewater effluents. In the present work, the electrochemical disinfection of saline water contaminated with bacteria was investigated in chloride-containing solutions using Sb-doped Sn 80% -W 20% -oxide anodes. The influence of current density, bacterial load, initial chloride concentration, solution pH, and the type of bacteria (E. coli D21, E. coli O157:H7, and E. faecalis) on disinfection efficacy was systematically examined. The impact of natural organic matter and a radical scavenger on the disinfection process was also examined. The electrochemical system was highly effective in bacterial inactivation for a 0.1 M NaCl solution contaminated with ∼10 7  CFU/mL bacteria by applying a current density ≥1 mA/cm 2 through the cell.100% inactivation of E. coli D21 was achieved with a contact time of less than 60 s and power consumption of 48 Wh/m 3 , by applying a current density of 6 mA/cm 2 in a 0.1 M NaCl solution contaminated with ∼10 7 CFU/mL. Reactive chlorine species as well as reactive oxygen species (e.g. hydroxyl radicals) generated in situ during the electrochemical process were determined to be responsible for inactivation of bacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enhanced formation of disinfection byproducts in shale gas wastewater-impacted drinking water supplies.

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Parker, Kimberly M; Zeng, Teng; Harkness, Jennifer; Vengosh, Avner; Mitch, William A

2014-10-07

The disposal and leaks of hydraulic fracturing wastewater (HFW) to the environment pose human health risks. Since HFW is typically characterized by elevated salinity, concerns have been raised whether the high bromide and iodide in HFW may promote the formation of disinfection byproducts (DBPs) and alter their speciation to more toxic brominated and iodinated analogues. This study evaluated the minimum volume percentage of two Marcellus Shale and one Fayetteville Shale HFWs diluted by fresh water collected from the Ohio and Allegheny Rivers that would generate and/or alter the formation and speciation of DBPs following chlorination, chloramination, and ozonation treatments of the blended solutions. During chlorination, dilutions as low as 0.01% HFW altered the speciation toward formation of brominated and iodinated trihalomethanes (THMs) and brominated haloacetonitriles (HANs), and dilutions as low as 0.03% increased the overall formation of both compound classes. The increase in bromide concentration associated with 0.01-0.03% contribution of Marcellus HFW (a range of 70-200 μg/L for HFW with bromide = 600 mg/L) mimics the increased bromide levels observed in western Pennsylvanian surface waters following the Marcellus Shale gas production boom. Chloramination reduced HAN and regulated THM formation; however, iodinated trihalomethane formation was observed at lower pH. For municipal wastewater-impacted river water, the presence of 0.1% HFW increased the formation of N-nitrosodimethylamine (NDMA) during chloramination, particularly for the high iodide (54 ppm) Fayetteville Shale HFW. Finally, ozonation of 0.01-0.03% HFW-impacted river water resulted in significant increases in bromate formation. The results suggest that total elimination of HFW discharge and/or installation of halide-specific removal techniques in centralized brine treatment facilities may be a better strategy to mitigate impacts on downstream drinking water treatment plants than altering

Disinfection capacity of PuriLens contact lens cleaning unit against Acanthamoeba.

Science.gov (United States)

Hwang, Thomas S; Hyon, Joon Young; Song, Jae Kyung; Reviglio, Victor E; Spahr, Harry T; O'Brien, Terrence P

2004-01-01

The PuriLens contact lens system is indicated for cleaning and disinfection of soft (hydrophilic) contact lenses by means of subsonic agitation to remove lens deposits and microorganisms, and ultraviolet irradiation of the storage solution for disinfection. The capacity of the PuriLens system to disinfect storage solutions contaminated with known concentrations of Staphylococcus aureus, Pseudomonas aeruginosa, and Acanthamoeba species was evaluated. An in vitro assessment of the antibacterial and antiparasitic efficacy of the PuriLens system was performed. Separated batches of the storage solution for the cleansing system were contaminated with stock strains of S. aureus and P. aeruginosa. A comparison of the microbiologic content was made between the solution before and after the cycle. The PuriLens system effectively eradicated S. aureus and P. aeruginosa organisms after a 15-minute cycle. However, viable cysts of acanthamoeba were recovered in the solution after the 15-minute cycle. The PuriLens system is highly efficient in protecting against contamination with common bacterial ocular pathogens. Acanthamoeba cysts, however, can survive in the solution or contact lens bath undergoing integrated subsonic debridement and indirect ultraviolet light disinfection. Use of chemical disinfecting solutions that contain agents such as chlorhexidine or other cationic antiseptics may be advisable in conjunction with use of the PuriLens device, especially in high-risk settings.

Microbiological evaluation of ultrasonic nebulization for disinfecting dental impressions.

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Mendonca, Marcio Jose; Rafael, Renata Santos; Camilotti, Veridiana; Menolli, Rafael Andrade; Sicoli, Eliseu Augusto; Teixeira, Nancielli; Sinhoreti, Mario Alexandre Coelho

2013-07-01

Disinfecting dental impressions is necessary to decrease the risk of cross-contamination in dental offices. Ultrasonic nebulization has been mentioned as a microbicidal technique that can be used to disinfect contaminated dental impressions. This study compared the microbicidal effect of 2% glutaraldehyde and 0.2% peracetic acid for the disinfection of dental impressions made with vinyl polysiloxane, using 2 disinfection methods: immersion and ultrasonic nebulization. Bactericial efficacy was examined using Staphylococcus aureus and Bacillus atrophaeus as indicators. Thirty impressions were obtained and distributed randomly in 5 groups (n = 6). Group 1 was immersed in 2% glutaraldehyde immersion for 10 minutes, Group 2 was immersed in 0.2% peracetic acid for 10 minutes, Group 3 underwent ultrasonic nebulization for 10 minutes in 2% glutaraldehyde solution, Group 4 underwent ultrasonic nebulization for 10 minutes in 0.2% peracetic acid solution, and Group 5 was a control group that received no disinfectant. Both solutions experienced a 100% reduction in microorganisms following ultrasonic nebulization, as did peracetic acid following immersion; however, immersion in glutaraldehyde demonstrated lower values of reduction in B atrophaeus group, with a statistically significant difference compared with the other experimental groups.

Evaluation of disinfecting effect of 5% sodium hypochlorite solution diluted to 2:100 along with the use of disposable covers on HBV contaminated dental office surfaces and equipments

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Arami S.

2008-04-01

Full Text Available Background and Aim: The efficiency of disinfecting materials and procedures in removal of contamination from dental surfaces and equipments is essential. In authors' previous study, daily use of 2:100 dilution of 5% sodium hypochlorite in water and disposable covers were recommended since HBV contamination was found on semi-critical parts of the operative dentistry department. The aim of this study was to evaluate the HBV contamination following application of the recommended procedures.Materials and Methods: The study was conducted in two parts. In the first cross-sectional part, samples were collected from 17 sites of dental surfaces. In the second interventional part samples were collected from 10 sites of 9 dental and 3 sites of 2 light cure units, before and after disinfection with 5% sodium hypochlorite solution diluted to 2:100. Sterile cotton swabs moistened with sterile BSAS (Bovine Serum Albumin in Sodium Chloride solution were used for sampling. Samples were tested by PCR technique in Pasteur Institute, Iran.Results: None of the samples collected in the first part of the study showed contamination. In the second part of the study, from 96 samples taken from various parts of dental and light cure units, before and after disinfection, there was only one HBV contaminated site before disinfection which showed no contamination after disinfection.Conclusion: Based on the results of this study, disinfecting procedure with 5% sodium hypochlorite solution diluted to 2:100 along with using disposable covers is effective in preventing HBV contamination.

Effective reprocessing of reusable dispensers for surface disinfection tissues – the devil is in the details

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Kampf, Günter; Degenhardt, Stina; Lackner, Sibylle; Ostermeyer, Christiane

2014-01-01

Background: It has recently been reported that reusable dispensers for surface disinfection tissues may be contaminated, especially with adapted Achromobacter species 3, when products based on surface-active ingredients are used. Fresh solution may quickly become recontaminated if dispensers are not processed adequately. Methods: We evaluated the abilities of six manual and three automatic processes for processing contaminated dispensers to prevent recolonisation of a freshly-prepared disinfectant solution (Mikrobac forte 0.5%). Dispensers were left at room temperature for 28 days. Samples of the disinfectant solution were taken every 7 days and assessed quantitatively for bacterial contamination. Results: All automatic procedures prevented recolonisation of the disinfectant solution when a temperature of 60–70°C was ensured for at least 5 min, with or without the addition of chemical cleaning agents. Manual procedures prevented recontamination of the disinfectant solution when rinsing with hot water or a thorough cleaning step was performed before treating all surfaces with an alcohol-based disinfectant or an oxygen-releaser. Other cleaning and disinfection procedures, including the use of an alcohol-based disinfectant, did not prevent recolonisation. Conclusions: These results indicate that not all processes are effective for processing reusable dispensers for surface-disinfectant tissues, and that a high temperature during the cleaning step or use of a biofilm-active cleaning agent are essential. PMID:24653973

Effective reprocessing of reusable dispensers for surface disinfection tissues – the devil is in the details

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Kampf, Günter

2014-03-01

Full Text Available [english] Background: It has recently been reported that reusable dispensers for surface disinfection tissues may be contaminated, especially with adapted , when products based on surface-active ingredients are used. Fresh solution may quickly become recontaminated if dispensers are not processed adequately. Methods: We evaluated the abilities of six manual and three automatic processes for processing contaminated dispensers to prevent recolonisation of a freshly-prepared disinfectant solution (Mikrobac forte 0.5%. Dispensers were left at room temperature for 28 days. Samples of the disinfectant solution were taken every 7 days and assessed quantitatively for bacterial contamination. Results: All automatic procedures prevented recolonisation of the disinfectant solution when a temperature of 60–70°C was ensured for at least 5 min, with or without the addition of chemical cleaning agents. Manual procedures prevented recontamination of the disinfectant solution when rinsing with hot water or a thorough cleaning step was performed before treating all surfaces with an alcohol-based disinfectant or an oxygen-releaser. Other cleaning and disinfection procedures, including the use of an alcohol-based disinfectant, did not prevent recolonisation.Conclusions: These results indicate that not all processes are effective for processing reusable dispensers for surface-disinfectant tissues, and that a high temperature during the cleaning step or use of a biofilm-active cleaning agent are essential.

Additional disinfection with a modified salt solution in a root canal model.

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van der Waal, Suzette V; Oonk, Charlotte A M; Nieman, Selma H; Wesselink, Paul R; de Soet, Johannes J; Crielaard, Wim

2015-10-01

The aim of this study is to investigate the disinfecting properties of a modified salt solution (MSS) and calcium hydroxide (Ca(OH)2) in a non-direct-contact ex-vivo model. Seventy-four single-canal roots infected with Enterococcus faecalis were treated with 1% sodium hypochlorite (NaOCl) irrigation or with NaOCl irrigation with subsequent dressing with MSS or Ca(OH)2. After removal of the dressings, the roots were filled with bacterial growth medium and incubated for seven days to enable the surviving bacteria to repopulate the root canal lumen. Growth was determined by sampling the root canals with paper points before treatment (S1), after treatment (S2) and incubation after treatment (S3). The colony forming units were counted at S1 and S2. At S3, growth was determined as no/yes regrowth. The Kruskal-Wallis, McNemar and χ(2) test were used for statistical analyses. At S2, in the NaOCl group, growth was found in 5 of 19 root canals. After the removal of MSS or Ca(OH)2 bacteria were retrieved from one root canal in both groups. At S3, repopulation of the root canals had occurred in 14 of 19 roots after sole NaOCl irrigation, 6 of 20 roots after MSS-dressing and in 14 of 20 roots after Ca(OH)2-dressing. MSS was more effective in preventing regrowth than Ca(OH)2 (P=0.009). The modified salt solution prevented regrowth in roots which indicates that it can eliminate persistent bacteria. Dressing the root canals with Ca(OH)2 did not provide additional disinfection after NaOCl irrigation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Improving stethoscope disinfection at a children's hospital.

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Zaghi, Justin; Zhou, Jing; Graham, Dionne A; Potter-Bynoe, Gail; Sandora, Thomas J

2013-11-01

Stethoscopes are contaminated with pathogenic bacteria and pose a risk for transmission of infections, but few clinicians disinfect their stethoscope after every use. We sought to improve stethoscope disinfection rates among pediatric healthcare providers by providing access to disinfection materials and visual reminders to disinfect stethoscopes. Prospective intervention study. Inpatient units and emergency department of a major pediatric hospital. Physicians and nurses with high anticipated stethoscope use. Baskets filled with alcohol prep pads and a sticker reminding providers to regularly disinfect stethoscopes were installed outside of patient rooms. Healthcare providers' stethoscope disinfection behaviors were directly observed before and after the intervention. Multivariable logistic regression models were created to identify independent predictors of stethoscope disinfection. Two hundred twenty-six observations were made in the preintervention period and 261 in the postintervention period (83% were of physicians). Stethoscope disinfection compliance increased significantly from a baseline of 34% to 59% postintervention (P stethoscope disinfection supplies and visible reminders outside of patient rooms significantly increased stethoscope disinfection rates among physicians and nurses at a children's hospital. This simple intervention could be replicated at other healthcare facilities. Future research should assess the impact on patient infections.

Cleaning and Disinfection of Bacillus cereus Biofilm.

Science.gov (United States)

Deal, Amanda; Klein, Dan; Lopolito, Paul; Schwarz, John Spencer

2016-01-01

Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to disassociated B. cereus spores and biofilm from a non-spore-forming species. Further, we assessed the impact that pre-cleaning has on increasing that susceptibility. Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to

Effectiveness of Four Disinfectants against Ebola Virus on Different Materials

Directory of Open Access Journals (Sweden)

Sophie Smither

2016-07-01

Full Text Available The West Africa Ebola virus (EBOV outbreak has highlighted the need for effective disinfectants capable of reducing viral load in a range of sample types, equipment and settings. Although chlorine-based products are widely used, they can also be damaging to equipment or apparatus that needs continuous use such as aircraft use for transportation of infected people. Two aircraft cleaning solutions were assessed alongside two common laboratory disinfectants in a contact kill assay with EBOV on two aircraft relevant materials representative of a porous and non-porous surface. A decimal log reduction of viral titre of 4 is required for a disinfectant to be deemed effective and two of the disinfectants fulfilled this criteria under the conditions tested. One product, Ardrox 6092, was found to perform similarly to sodium hypochlorite, but as it does not have the corrosive properties of sodium hypochlorite, it could be an alternative disinfectant solution to be used for decontamination of EBOV on sensitive apparatus.

Limitation of the spread and impact of infectious coryza through the use of a continuous disinfection programme

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R.R. Bragg

2004-11-01

Full Text Available The effect of a continuous disinfection programme, using the non-toxic disinfectant Virukill, in layers, on the spread and impact of infectious coryza, caused by Haemophilus paragallinarum was evaluated. In this experiment, both unvaccinated layers and layers vaccinated against infectious coryza were used. Duplicate smaller groups of vaccinated and unvaccinated chickens were challenged with different serovars of both NAD-dependent as well as NAD-independent isolates of Haemophilus paragallinarum. One group of chickens challenged with each of the different bacterial serovars was treated with the continuous disinfection programme, while the other group remained as the untreated controls. The clinical signs of infectious coryza were evaluated over a period of 20 days in each group. The egg production over this period was also evaluated. It was found in all experimental challenges, that the severity of the symptoms was reduced in the birds receiving the continuous disinfection programme. The drop in egg production was also found to be less severe in the treated groups when compared to the untreated control groups. The duration of infection was found to be either unchanged, or shorter in the birds treated with the continuous disinfection programme. In none of the experimental challenges was the duration or expression of clinical signs of IC increased due to the continuous disinfection programme.

The impact of iodinated X-ray contrast agents on formation and toxicity of disinfection by-products in drinking water.

Science.gov (United States)

Jeong, Clara H; Machek, Edward J; Shakeri, Morteza; Duirk, Stephen E; Ternes, Thomas A; Richardson, Susan D; Wagner, Elizabeth D; Plewa, Michael J

2017-08-01

The presence of iodinated X-ray contrast media (ICM) in source waters is of high concern to public health because of their potential to generate highly toxic disinfection by-products (DBPs). The objective of this study was to determine the impact of ICM in source waters and the type of disinfectant on the overall toxicity of DBP mixtures and to determine which ICM and reaction conditions give rise to toxic by-products. Source waters collected from Akron, OH were treated with five different ICMs, including iopamidol, iopromide, iohexol, diatrizoate and iomeprol, with or without chlorine or chloramine disinfection. The reaction product mixtures were concentrated with XAD resins and the mammalian cell cytotoxicity and genotoxicity of the reaction mixture concentrates was measured. Water containing iopamidol generated an enhanced level of mammalian cell cytotoxicity and genotoxicity after disinfection. While chlorine disinfection with iopamidol resulted in the highest cytotoxicity overall, the relative iopamidol-mediated increase in toxicity was greater when chloramine was used as the disinfectant compared with chlorine. Four other ICMs (iopromide, iohexol, diatrizoate, and iomeprol) expressed some cytotoxicity over the control without any disinfection, and induced higher cytotoxicity when chlorinated. Only iohexol enhanced genotoxicity compared to the chlorinated source water. Copyright © 2017. Published by Elsevier B.V.

Effects of disinfecting alginate impressions on the scratch hardness of stone models.

Science.gov (United States)

Hiraguchi, Hisako; Nakagawa, Hisami; Wakashima, Mitsuru; Miyanaga, Kohichi; Saigo, Masataka; Nishiyama, Minoru

2006-03-01

This study investigated the effects of disinfecting alginate impressions on the scratch depth of resultant stone models. Eleven brands of alginate impression material and two disinfectants, 1% sodium hypochlorite and 2% glutaraldehyde, were used. Impressions were immersed in disinfectant solutions or stored in sealed bags after spraying with disinfectants, and then poured with a type V dental stone. The scratch depth of the stone model obtained from disinfected impression was measured. The storage of alginate impressions after spraying with disinfectants did not increase the scratch depth of resultant stone models. However, the effect of immersion in disinfectants on scratch depth varied with the brand of the alginate impression material.

Rates of Decomposition of N-Chloramine Disinfectant Compounds in Aqueous Solutions

International Nuclear Information System (INIS)

EI-Bellihi, E.E.

2009-01-01

The effect of temperature, ph, and salt effects on the decomposition kinetics of hydrolysis of N-chloramine disinfectant compounds [chloramine-B, chloramine-T, N-chlorosuccinimide (NCS), and 1,3-dichloro-5,5-dimethyl hydantoin (DCDMH or Halane)] in aqueous solutions was studied. The results should that the hydrolytic stability of CB and CT is greater than that of NCS and halane. Using CT, which is practical in use for its long contact times, reduced its initial concentration in aqueous solution from 100 ppm to about 20 ppm after a period of 6 months. The study also showed that the rate of hydrolysis of NCS is almost independent on the H + ions concentration. On the other hand, the rates of hydrolysis of CB and CT depend strongly on the hydrogen ion (H + ) concentration where the kinetic of the reaction changes from zero-order to a first order. The thermodynamic parameters of activation were calculated and showed that the entropies of activation have large negative values due to the increase in electrostriction and in a loss of freedom of the solvent water molecules associated with the separation of ions in the transition state. A linear compensation between ΔH and ΔS suggests that in the pure aqueous solutions, the reaction mechanism is almost the same for all the chloramine compounds under investigation

Disinfection of dental impressions - compliance to accepted standards.

Science.gov (United States)

Almortadi, N; Chadwick, R G

2010-12-18

The responsibility of ensuring impressions have been cleaned and disinfected before dispatch to the dental laboratory lies solely with the dentist. Uncertainty of impression disinfection risks both the health of the receiving dental technician and potential repeat disinfection of an already disinfected impression with detrimental consequences for its dimensions. To ascertain, from the perspectives of dentists and dental technicians, current impression decontamination and disinfection practices with, in the case of the technicians, an estimate of the relative prevalence of contaminated voids within apparently disinfected impressions. Anonymous postal questionnaire. Dentist (n = 200) and dental technician (n = 200) potential participants, selected at random from the registers held by the General Dental Council, were invited to complete an anonymous postal questionnaire that sought to establish current practices and perceived effectiveness of impression disinfection. Questionnaire return rates of 42.1% and 31.2% were recorded for dentists and dental technicians respectively. A wide range of solutions, at different dilutions of the same product, was used by the dentists to disinfect dental impressions. 37.2% rinsed the impressions with water, and 2.6% always brushed debris away, before disinfection. 24.7% of dentists did not inform the laboratory of disinfection. Irrespective of the disinfection status of the received impressions, 50% of the responding dental technicians disinfected all impressions. 95% of them had received blood-contaminated impressions. 15% had encountered blood-filled voids upon trimming back the peripheries of impressions. 64.7% were confident that the impressions received by them had been disinfected by the dentists. Compliance with good practice is less than ideal and education in impression disinfection for both dentists and dental technicians is required to address this.

The Disinfecting Potential of Contact Lens Soutions used by Sultan Qaboos University Students

Science.gov (United States)

Nzeako, B. C.; Al-Sumri, Sara H.

2011-01-01

Objectives: This study aimed to determine the disinfecting potential of some contact lens solutions used by some university students in Oman. Methods: This work was carried out from January to June 2010 in the Department of Microbiology & Immunology, College of Medicine and Health Sciences, Sultan Qaboos University, Oman. Fifty disinfecting solutions, in which contact lenses were disinfected according to the manufacturers’ instructions, were collected from the students and plated on various microbiological culture media. Bacterial isolates were identified by API-20E, API-20NE and Phoenix automated systems while fungi were identified by their cultural characteristics and biochemistry. Results: From 98 isolates, Pseudomonas aeruginosa was 23.5%; Penicillium, 13%; Candida species, 9.2%; coagulase negative staphylococci, 9.2%; Serratia marcescens, 6.1%; Bacillus, 5.1%; Aspergillus flavus, 5.1%; Serratia liquefaciens, Pseudomonas fluorescens, Enterobacter cloacae and Aspergillus niger, 4.1% each; Chryseomonas luteola and Chryseomonas indologenes, 3.1% each; Stenotrophomonas maltophilia, Serratia odorifera, 2.0% each; Enterobacter aerogenes and Klebsiella pneumoniae, 1% each. Most isolates (65%) came from polyhexanide containing solutions. Conclusion: Contact lens disinfecting solutions with the same formulations, but manufactured by different companies, possessed different disinfecting potentials. PMID:21969898

Influence of disinfectant solutions on test materials used for the determination of masticatory performance

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Simone Silvério Campos

2013-06-01

Full Text Available Masticatory function can be evaluated objectively as the capacity of an individual to fragment solid food after a fixed number of chewing cycles, the so-called masticatory performance (MP. The objective of this study was to evaluate the reliability of four different test materials (Optosil, Optocal, Zetapuls, and Perfil and five disinfection protocols by aspersion and immersion (no disinfection, 2% glutaraldehyde, 2% chlorhexidine, 5.25% sodium hypochlorite, and 70% alcohol on the MP, determined at three moments (24 hours, 15 and 60 days after storing the fragmented blocks. MP was evaluated by calculating X50 through the sieving technique and the Rosim-Ramler equation. The weight and microbiologic count (colony forming units, CFUs of chewed blocks were measured to identify any variations that would make MP determination unfeasible. Differences in MP were observed among the materials (p 0.05. The time and disinfection type had no influence on MP (p > 0.05. The number of CFUs differed between the nondisinfected group and all other disinfection groups at all time points (p < 0.01. No other significant difference in CFU count between disinfection groups was observed. In conclusion, disinfection did not alter the reliability of the test materials for the MP calculation for up to 60 days.

Antimicrobial Efficacy of Multipurpose Disinfecting Solutions in the Presence of Contact Lenses and Lens Cases.

Science.gov (United States)

Gabriel, Manal M; McAnally, Cindy; Bartell, John

2018-03-01

The aim of this study was to use antimicrobial efficacy endpoint methodology to determine compatibility of multipurpose disinfecting solutions (MPSs), lens cases, and hydrogel lenses for disinfection (AEEMC) against International Organization for Standardization (ISO)-specified microorganisms and clinical ocular isolates of Stenotrophomonas maltophilia. Six MPSs (PQ/Aldox 1, 2, and 3; PQ/Alexidine; PQ/PHMB; and PHMB) were challenged against ISO-specified microorganisms and S. maltophilia using the AEEMC test. AEEMC tests were performed with and without balafilcon A, etafilcon A, and senofilcon A lenses in lens cases with organic soil. Exposure times included disinfection time (DT) and 24 hr. Additionally, all six MPSs were challenged with two strains of S. maltophilia, based on the ISO Stand-alone test. The efficacy against bacteria for PQ/Aldox and PQ/Alexidine MPSs was not diminished by the presence of lenses. The efficacy of PQ/PHMB and PHMB MPSs against Serratia marcescens was significantly reduced compared with the no-lens control at DT for at least one lens type. The PHMB MPS with lenses present also demonstrated reduced efficacy against Staphylococcus aureus at DT versus the control. PQ/Aldox MPSs retained activity against Fusarium solani with lenses present; however, all other test MPSs demonstrated reduced F. solani efficacy at DT with lenses present. With lenses, all MPSs showed reduced efficacy against Candida albicans. AEEMC antimicrobial efficacy test results vary based on challenge microorganism, contact lenses, and MPS biocide systems. This study highlights the importance of evaluating MPSs for compatibility with lenses and lens cases.

Preliminary SEM Observations on the Surface of Elastomeric Impression Materials after Immersion or Ozone Disinfection

Science.gov (United States)

Prombonas, Anthony; Yannikakis, Stavros; Karampotsos, Thanasis; Katsarou, Martha-Spyridoula; Drakoulis, Nikolaos

2016-01-01

Introduction Surface integrity of dental elastomeric impression materials that are subjected to disinfection is of major importance for the quality of the final prosthetic restorations. Aim The aim of this qualitative Scanning Electronic Microscopy (SEM) study was to reveal the effects of immersion or ozone disinfection on the surface of four dental elastomeric impression materials. Materials and Methods Four dental elastomeric impression material brands were used (two vinyl polysiloxane silicones, one polyether, and one vinyl polyether silicone). Total of 32 specimens were fabricated, eight from each impression material. Specimens were immersion (0.525% sodium hypochlorite solution or 0.3% benzalkonium chloride solution) or ozone disinfected or served as controls and examined with SEM. Results Surface degradation was observed on several speci-mens disinfected with 0.525% sodium hypochlorite solution. Similar wavy-wrinkling surface structures were observed in almost all specimens, when treated either with 0.3% benzalkonium chloride solution or ozone. Conclusion The SEM images obtained from this study revealed that both immersion disinfectants and ozone show similar impression material surface alterations. Ozone seems to be non-inferior as compared to immersion disinfectants, but superior as to environmental protection. PMID:28208993

Wettability changes in polyether impression materials subjected to immersion disinfection.

Science.gov (United States)

Shetty, Shweta; Kamat, Giridhar; Shetty, Rajesh

2013-07-01

Disinfection of impression materials prevents cross-contamination; however, the disinfectants may alter the wettability property. The purpose of this investigation was to evaluate the wettability changes of polyether impression material after immersing in four different chemical disinfectant solutions for a period of 10 min and 30 min, respectively. A total of 45 samples of polyether dental impression material (Impregum soft, 3MESPE, St. Paul, MN, USA) were randomly divided into nine groups with five specimens each. Each specimen was disc shaped, flat of 32 mm diameter and 3 mm thickness. The samples were immersed in four disinfectant solutions: 2% Glutaraldehyde, 5% sodium hypochlorite, 0.05% iodophor, and 5.25% phenol for 10 min and 30 min, respectively. The control was without disinfection. Wettability of the samples was assessed by measuring the contact angle by using the Telescopic Goniometer. Data were subjected to analysis of variance (Fisher's test) and Tukey's post hoc test for multiple comparisons at 5% level of significance. The contact angle of 20.21° ± 0.22° were recorded in the control samples. After 10 min, the samples that were immersed in 5% sodium hypochlorite and 5.25% phenol showed significant statistical increase in the contact angle as compared to the control (P polyether material. Within the limitations of the study, 2% glutaraldehyde proved safe for 10 min of immersion disinfection while 0.05% iodophor holds promise as an effective disinfectant without affecting the wettability of the material.

Optimization of fixed titanium dioxide film on PET bottles and visual indicator for water disinfection

Science.gov (United States)

Heredia-Munoz, Manuel Antonio

Water is perhaps the most important resource that sustains human life. According to the World Health Organization (WHO), almost two billion people do not have access to the required water that is needed to satisfy their daily needs and one billion do not have access to clean sources of water for consumption, most of them living in isolated and poor areas around the globe. Poor quality water increases the risk of cholera, typhoid fever and dysentery, and other water-borne illness making this problem a real crisis that humankind is facing. Several water disinfection technologies have been proposed as solutions for this problem. Solar water disinfection using TiO2 coated PET bottles was the alternative that is studied in this work. This technology does not only inactivate bacteria but also disintegrates organic chemicals that can be present in water. The objectives of this work address the optimization of the TiO 2 coated PET bottles technologies. The improvement on the bottle coating process, using two coats of 10% W/V of TiO2 in a solution of vinegar and sodium bicarbonate to form the TiO2 film, the use of a different indigo carmine (1.25 X 10-1mg/pill) concentration in the pill indicator of contamination, the increase of the disinfection rate through shaking the bottles, degradation under intermittent UV radiation and the effect of bottle size on photocatalytic water disinfection were among the most important findings. A new mathematical model that describes better photocatalytic water disinfection in TiO2 coated bottles and simulates water disinfection under different working conditions was another important achievement. These results can now be used to design a strategy for disseminating this technology in areas where it is required and, in that way, generate the greatest positive impact on the people needing safe drinking water.

A practical evaluation of detergent and disinfectant solutions on ...

African Journals Online (AJOL)

Student01

2012-01-06

Jan 6, 2012 ... inactivation efficacy and effect on material corrosion ... Cleaning and disinfection agents were evaluated against selected bacteria on ... bacteria strains: Escherichia coli K12, E. coli DSM 682, Salmonella ... in terms of the lifespan of the equipment, and also ..... Individual descriptions of the observed basis.

Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection

Energy Technology Data Exchange (ETDEWEB)

Barber, Larry B. [U.S. Geological Survey, 3215 Marine St., Boulder, CO 80303 (United States); Hladik, Michelle L. [U.S. Geological Survey, 6000 J Street Placer Hall, Sacramento, CA 95819 (United States); Vajda, Alan M. [University of Colorado, Department of Integrative Biology, CB 171, Denver, CO 80217 (United States); Fitzgerald, Kevin C. [U.S. Geological Survey, 3215 Marine St., Boulder, CO 80303 (United States); AECOM, 500 West Jefferson St., Ste. 1600, Louisville, KY 40202 (United States); Douville, Chris [City of Boulder, 4049 75th Street, Boulder, CO 80301 (United States)

2015-10-01

The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m{sup 3} d{sup −1} design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration = 2.7 μg L{sup −1}; n = 5) and 10 HDBPs (mean total concentration = 4.5 μg L{sup −1}), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration = 1.4 μg L{sup −1}) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had

Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection

International Nuclear Information System (INIS)

Barber, Larry B.; Hladik, Michelle L.; Vajda, Alan M.; Fitzgerald, Kevin C.; Douville, Chris

2015-01-01

The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m 3 d −1 design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration = 2.7 μg L −1 ; n = 5) and 10 HDBPs (mean total concentration = 4.5 μg L −1 ), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration = 1.4 μg L −1 ) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had greater relative

A survey of the radiographic cassettes disinfection of university hospitals in seoul

International Nuclear Information System (INIS)

Kweon, Dae Cheol; Park, Peom; Kim, Moon Sun; Kim, Dong Sung

2001-01-01

The purpose of this study is to prevent nosocomial infection in patients through contact of radiographic cassettes. Data were collected from radiographers working in 29 university hospitals in Seoul in February and March 2001. Radiographic cassettes were disinfected daily in 5 hospitals, weekly in 4 hospitals, monthly in 5 hospitals, bimonthly in 1 hospital and once every three months in another hospital. 12 other hospitals do not practice regular disinfections of radiographic cassettes. Gauze soaked in disinfectant solution is used in 7 hospitals while 11 hospitals used cotton and cloth soaked in disinfectant solution to clean the radiographic cassettes. 26 hospitals used 99% alcohol based disinfectant solutions while 3 hospitals used 75% alcohol based disinfectant, 26 hospitals use of intercourse cassettes outpatients and in patients. In 26 hospitals, all patients shared the same set of radiographic cassettes used in the hospitals, or in 26 hospitals, separate sets of radiographic cassettes are used for outpatients and inpatients. Separate sets of cassettes are used for ICU and inpatients in 6 others hospitals. 23 hospitals used the same sets of radiographic cassettes for all their patients. radiographic cassettes are cleaned in wash area in the study room of the radiographic department in 17 hospitals. 12 other hospitals do not have designated cleaning areas for the cassettes. All radiographers practiced hands washing with soap. All 29 hospitals surveyed have infection control committee. However, only 9 out of the 29 hospitals surveyed provided Infection · disinfections control education to radiographers. Only 3 hospitals have radiographers sitting in the infection control committee. Infection management education is conducted in 63 hospitals annually, twice a year in 1 hospital and once every 3 months in 2 hospitals

Characterization of a stirred tank electrochemical cell for water disinfection processes

International Nuclear Information System (INIS)

Polcaro, A.M.; Vacca, A.; Mascia, M.; Palmas, S.; Pompei, R.; Laconi, S.

2007-01-01

Laboratory experiments were performed to characterize the behaviour of an electrochemical cell equipped with boron-doped diamond anodes and to verify its effectiveness in water disinfection. The hydrodynamic regime was determined when the cell worked either in batch or in continuous mode. Galvanostatic electrolyses of aqueous 1 mM Na 2 SO 4 solutions were performed to investigate on the oxidant production in different experimental conditions. The same solutions contaminated by E. coli, enterococci and coliforms were used as test media to verify the effectiveness of the system in the disinfection process. Experimental results indicated that the major inactivation mechanism of bacteria in the electrochemical cell is a disinfection by electrochemically generated oxidants, however a cooperative effect of superficial reaction has to be taken into account. The great capability of BDD anode to produce reactive oxygen species (ROS) and other oxidizing species during the electrolysis allows to establish a chlorine-free disinfection process

Effect of mixing techniques on bacterial attachment and disinfection time of polyether impression material.

Science.gov (United States)

Guler, Umut; Budak, Yasemin; Ruh, Emrah; Ocal, Yesim; Canay, Senay; Akyon, Yakut

2013-09-01

The aim of this study was 2-fold. The first aim was to evaluate the effects of mixing technique (hand-mixing or auto-mixing) on bacterial attachment to polyether impression materials. The second aim was to determine whether bacterial attachment to these materials was affected by length of exposure to disinfection solutions. Polyether impression material samples (n = 144) were prepared by hand-mixing or auto-mixing. Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa were used in testing. After incubation, the bacterial colonies were counted and then disinfectant solution was applied. The effect of disinfection solution was evaluated just after the polymerization of impression material and 30 min after polymerization. Differences in adherence of bacteria to the samples prepared by hand-mixing and to those prepared by auto-mixing were assessed by Kruskal-Wallis and Mann-Whitney U-tests. For evaluating the efficiency of the disinfectant, Kruskal-Wallis multiple comparisons test was used. E. coli counts were higher in hand-mixed materials (P 2.394). The methods used for mixing polyether impression material did not affect bacterial attachment to impression surfaces. In contrast, the disinfection procedure greatly affects decontamination of the impression surface.

Resistance of Pseudomonas aeruginosa isolates to hydrogel contact lens disinfection correlates with cytotoxic activity.

Science.gov (United States)

Lakkis, C; Fleiszig, S M

2001-04-01

One of the most common pathogens in infection of hydrogel contact lens wearers is Pseudomonas aeruginosa, which can gain access to the eye via contamination of the lens, lens case, and lens care solutions. Only one strain per species is used in current regulatory testing for the marketing of chemical contact lens disinfectants. The aim of this study was to determine whether P. aeruginosa strains vary in their susceptibility to hydrogel contact lens disinfectants. A method for rapidly screening bacterial susceptibility to contact lens disinfectants was developed, based on measurement of the MIC. The susceptibility of 35 P. aeruginosa isolates to two chemical disinfectants was found to vary among strains. MICs ranged from 6.25 to 100% for both disinfectants at 37 degrees C, and a number of strains were not inhibited by a 100% disinfectant concentration in the lens case environment at room temperature (22 degrees C). Resistance to disinfection appeared to be an inherent rather than acquired trait, since some resistant strains had been isolated prior to the introduction of the disinfectants and some susceptible P. aeruginosa strains could not be made more resistant by repeated disinfectant exposure. A number of P. aeruginosa strains which were comparatively more resistant to short-term disinfectant exposure also demonstrated the ability to grow to levels above the initial inoculum in one chemical disinfectant after long-term (24 to 48 h) disinfectant exposure. Resistance was correlated with acute cytotoxic activity toward corneal epithelial cells and with exsA, which encodes a protein that regulates cytotoxicity via a complex type III secretion system. These results suggest that chemical disinfection solutions may select for contamination with cytotoxic strains. Further investigation of the mechanisms and factors responsible for resistance may also lead to strategies for reducing adverse responses to contact lens wear.

Efficacy of a variety of disinfectants against Listeria spp.

Science.gov (United States)

Best, M; Kennedy, M E; Coates, F

1990-02-01

The efficacy of 14 disinfectants against Listeria innocua and two strains of Listeria monocytogenes in the presence of organic matter was studied. Quantitative efficacy tests were used. Many of the disinfectants tested were not as effective on Listeria spp. when the test organisms were dried onto the surface of steel disks (carrier tests) as they were when the organisms were placed in suspension (suspension test). The presence of whole serum and milk (2% fat) further reduced the disinfectant capacities of most of the formulations studied. Only three disinfectants (povidone-iodine, chlorhexidine gluconate, and glutaraldehyde) were effective in the carrier test in the presence of serum; however, all three were ineffective when challenged with milk (2% fat). Only one solution, sodium dichloroisocyanurate, was effective in the presence of milk. All but four formulations (chloramine-T, phosphoric acid, an iodophor, and formaldehyde) were effective in the suspension tests, regardless of the organic load. L. monocytogenes was observed to be slightly more resistant to disinfection than L. innocua was. There was no difference in disinfectant susceptibility between the two strains of L. monocytogenes. These findings emphasize the need for caution in selecting an appropriate disinfectant for use on contaminated surfaces, particularly in the presence of organic material.

PROBIOTIC CLEANING PREPARATIONS VERSUS CHEMICAL DISINFECTANTS

Directory of Open Access Journals (Sweden)

W. Luepcke

2017-12-01

Full Text Available Probiotic detergents are increasingly used and are a real alternative for limiting the use of chemical cleaners, chemical disinfectants and antibiotics. They therefore have a great future because they contribute to animal health, to the hygienic production of food products of animal origin and to their harmlessness and to consumer health and environmental protection where they even have a beneficial effect on the microflora apart from chemical disinfectants that have a negative impact and destroy the beneficial microflora.

Water disinfection agents and disinfection by-products

Science.gov (United States)

Ilavský, J.; Barloková, D.; Kapusta, O.; Kunštek, M.

2017-10-01

The aim of this work is to describe factors of water quality change in the distribution network and legislative requirements in Slovakia for disinfectants and disinfection byproducts (DBPs). In the experimental part, the time dependence of the application of the chlorine dioxide and sodium hypochlorite on the formation of some by-products of disinfection for drinking water from WTP Hriňová is studied. We monitored trihalomethanes, free chlorine, chlorine dioxide and chlorites.

Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection

Science.gov (United States)

Barber, Larry B.; Hladik, Michelle; Vajda, Alan M.; Fitzgerald, Kevin C.; Douville, Chris

2015-01-01

The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m3 d−1 design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration = 2.7 μg L−1; n=5) and 10 HDBPs (mean total concentration = 4.5 μg L−1), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration = 1.4 μg L−1) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had greater relative

Spiral-shaped disinfection reactors

KAUST Repository

Ghaffour, Noreddine

2015-08-20

This disclosure includes disinfection reactors and processes for the disinfection of water. Some disinfection reactors include a body that defines an inlet, an outlet, and a spiral flow path between the inlet and the outlet, in which the body is configured to receive water and a disinfectant at the inlet such that the water is exposed to the disinfectant as the water flows through the spiral flow path. Also disclosed are processes for disinfecting water in such disinfection reactors.

Chlorine disinfection of grey water for reuse: effect of organics and particles.

Science.gov (United States)

Winward, Gideon P; Avery, Lisa M; Stephenson, Tom; Jefferson, Bruce

2008-01-01

Adequate disinfection of grey water prior to reuse is important to prevent the potential transmission of disease-causing microorganisms. Chlorine is a widely utilised disinfectant and as such is a leading contender for disinfection of grey water intended for reuse. This study examined the impact of organics and particles on chlorine disinfection of grey water, measured by total coliform inactivation. The efficacy of disinfection was most closely linked with particle size. Larger particles shielded total coliforms from inactivation and disinfection efficacy decreased with increasing particle size. Blending to extract particle-associated coliforms (PACs) following chlorine disinfection revealed that up to 91% of total coliforms in chlorinated grey water were particle associated. The organic concentration of grey water affected chlorine demand but did not influence the disinfection resistance of total coliforms when a free chlorine residual was maintained. Implications for urban water reuse are discussed and it is recommended that grey water treatment systems target suspended solids removal to ensure removal of PACs prior to disinfection.

Impact of donor arm cleaning with different aseptic solutions for prevention of contamination in blood bags.

Science.gov (United States)

Patel, Tanvi G; Shukla, Rinku V; Gupte, Snehalata C

2013-03-01

Transfusion associated sepsis cases are encountered occasionally and bacterial transmission remains the major cause. The goal of our study was to compare the efficacy of disinfectants in phlebotomy site preparation. After selection of donor the antecubital fossa area of the arm was disinfected with different types of disinfectants namely sprit (70% isopropyl alcohol), povidone iodine (0.5% w/v available iodine in distilled water), savlon (1.5% v/v chlorhexidine gluconate solution and 3.0% cetrimide solution) and combination of sprit and povidone iodine. Swabs were collected from 20 donors using a sterile forceps, after cleaning with different antiseptic solutions. Swab was streaked on blood agar plate aseptically and the plate was incubated at 37°C for 24 h. Colonies were counted and a single colony was re-cultured by growing on nutrient and Mac-Conkey agar. The biochemical characteristics were determined by performing Gram staining, Motility, Catalase and Oxidase tests. The mean values of colonies were significantly higher with savlon compared to other three solutions. The difference was statistically significant by "t" test (t values 1.7-3.0; P bag were aseptically inoculated in aerobic and anaerobic culture bottles to be tested on BacT/Alert system. The bag containing donor's blood did not show any contamination when three cleanings were carried out using sprit, povidone iodine and spirit respectively.

Comparative Evaluation of Tensile Strength in Die Stone Incorporated with Sodium and Calcium Hypochlorite as Disinfectants: An in vitro Study.

Science.gov (United States)

Pramodh, N R; Kumar, C N Vijay; Pradeep, M R; Naik, Ravi; Mahesh, C S; Kumari, Manju R

2017-12-01

The aim of this study was to evaluate the tensile strength of die stone incorporated with sodium and calcium hypochlorite as disinfectants. Two commercially available type IV die stone (Kalrock: Kalabhai Karson Pvt., Ltd and Pearlstone: Asian Chemicals) and two commercially available disinfectant solutions (sodium hypochlorite and calcium hypochlorite: Beachem Laboratory Chemical Private Limited, Chennai and Leo Chem Private Limited, Bengaluru) were used in this study, and the tensile strength was measured using Lloyd's Universal Testing Machine. The results show that incorporating the disinfecting solutions decreases the tensile strength of both products. The effect of decreasing tensile strength on type IV gypsum product is seen more in calcium hypochlorite when compared with sodium hypochlorite disinfecting solution, and the tensile strength of Kalrock specimens is higher than Pearlstone specimens after disinfecting with sodium hypochlorite and calcium hypochlorite solution. The statistical results also show significant results in all the groups when compared with the control group. The incorporation of sodium and calcium hypochlorite disinfecting solutions is not an encouraging method for both die materials as it reduces the tensile strength of type IV gypsum product. Tensile strength of Kalstone® die material is superior than Pearlstone® die material after mixing with sodium hypochlorite and calcium hypochlorite. According to the recommendations of Americans with Disability Act (ADA) and the Centers for Disease Control and Prevention, disinfecting the whole cast without or minimal changes in physical and mechanical properties was the motto of the study. The tensile strength in type IV gypsum product plays a most important role in retrieval of cast from impression, especially in narrow tooth preparation. This study reveals that incorporating method of disinfecting solutions is not recommended as it reduces the tensile strength.

Is free halogen necessary for disinfection?

Science.gov (United States)

Williams, D E; Elder, E D; Worley, S D

1988-10-01

The principle of Le Chatelier was used in demonstrating that 3-chloro-4,4-dimethyl-2-oxazolidinone (compound 1) itself kills Staphylococcus aureus rather than the very small amount of free chlorine in hydrolysis equilibrium with compound 1. On the other hand, when the N-bromo analog of compound 1 (compound 1B) was used as the disinfectant, the mixture of combined compound 1B and free bromine formed in the hydrolysis equilibrium provided disinfection. When the hydrolysis equilibrium for 1B was suppressed to the level at which a negligible amount of free bromine remained in solution, combined compound 1B was much more efficacious than combined compound 1 at killing S. aureus.

Clinical and cost effectiveness of eight disinfection methods for terminal disinfection of hospital isolation rooms contaminated with Clostridium difficile 027.

Science.gov (United States)

Doan, L; Forrest, H; Fakis, A; Craig, J; Claxton, L; Khare, M

2012-10-01

Clostridium difficile spores can survive in the environment for months or years, and contaminated environmental surfaces are important sources of nosocomial C. difficile transmission. To compare the clinical and cost effectiveness of eight C. difficile environmental disinfection methods for the terminal cleaning of hospital rooms contaminated with C. difficile spores. This was a novel randomized prospective study undertaken in three phases. Each empty hospital room was disinfected, then contaminated with C. difficile spores and disinfected with one of eight disinfection products: hydrogen peroxide vapour (HPV; Bioquell Q10) 350-700 parts per million (ppm); dry ozone at 25 ppm (Meditrox); 1000 ppm chlorine-releasing agent (Actichlor Plus); microfibre cloths (Vermop) used in combination with and without a chlorine-releasing agent; high temperature over heated dry atomized steam cleaning (Polti steam) in combination with a sanitizing solution (HPMed); steam cleaning (Osprey steam); and peracetic acid wipes (Clinell). Swabs were inoculated on to C. difficile-selective agar and colony counts were performed pre and post disinfection for each method. A cost-effectiveness analysis was also undertaken comparing all methods to the current method of 1000 ppm chlorine-releasing agent (Actichlor Plus). Products were ranked according to the log(10) reduction in colony count from contamination phase to disinfection. The three statistically significant most effective products were hydrogen peroxide (2.303); 1000 ppm chlorine-releasing agent (2.223) and peracetic acid wipes (2.134). The cheaper traditional method of using a chlorine-releasing agent for disinfection was as effective as modern methods. Copyright © 2012 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Selecting a Sustainable Disinfection Technique for Wastewater Reuse Projects

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Jorge Curiel-Esparza

2014-09-01

Full Text Available This paper presents an application of the Analytical Hierarchy Process (AHP by integrating a Delphi process for selecting the best sustainable disinfection technique for wastewater reuse projects. The proposed methodology provides project managers a tool to evaluate problems with multiple criteria and multiple alternatives which involve non-commeasurable decision criteria, with expert opinions playing a major role in the selection of these treatment technologies. Five disinfection techniques for wastewater reuse have been evaluated for each of the nine criteria weighted according to the opinions of consulted experts. Finally, the VIKOR method has been applied to determine a compromise solution, and to establish the stability of the results. Therefore, the expert system proposed to select the optimal disinfection alternative is a hybrid method combining the AHP with the Delphi method and the VIKOR technique, which is shown to be appropriate in realistic scenarios where multiple stakeholders are involved in the selection of a sustainable disinfection technique for wastewater reuse projects.

Antibacterial efficacy of commercial disinfectants on dirt floor used in poultry breeder houses

Directory of Open Access Journals (Sweden)

F Pilotto

2007-06-01

Full Text Available Dirt floors are used on most Brazilian poultry farms since the construction of concrete floors is very expensive. In vitro tests carried out to verify the effectiveness of disinfectants do not consider the adverse conditions found in poultry farms. Therefore, the present study aimed at evaluating the effect of six commercial disinfectants on the reduction of total and fecal coliforms on the dirt floor of breeder houses. The amount of disinfectant solution to be used per square meter was defined by counting total and fecal coliforms at different soil depths and by analyzing soil physical properties. Coliforms were detected at 0.5 cm, and one liter of disinfectant solution was sufficient for soil saturation at this depth. After that, the efficacy of six commercial products (caustic soda, hydrated lime, phenols 1 and 2, iodine, glutaraldehyde, and quaternary ammonium in reducing the number of coliforms, after six hours of contact with the dirt floor, was assessed using the most probable number (MPN method. Escherichia coli specimens isolated from the dirt floor were used to evaluate in vitro effectiveness of disinfectants. Products that yielded the best results in the MPN method were also effective in the in vitro tests. Among the tested disinfectants, hydrated lime was the most efficient, reducing the initial contamination by 2.9 log after six hours of contact with the dirt floor.

Impact of UV and Peracetic Acid Disinfection on the Prevalence of Virulence and Antimicrobial Resistance Genes in Uropathogenic Escherichia coli in Wastewater Effluents

Science.gov (United States)

Biswal, Basanta Kumar; Khairallah, Ramzi; Bibi, Kareem; Mazza, Alberto; Gehr, Ronald; Masson, Luke

2014-01-01

Wastewater discharges may increase the populations of pathogens, including Escherichia coli, and of antimicrobial-resistant strains in receiving waters. This study investigated the impact of UV and peracetic acid (PAA) disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli (UPEC), the most abundant E. coli pathotype in municipal wastewaters. Laboratory disinfection experiments were conducted on wastewater treated by physicochemical, activated sludge, or biofiltration processes; 1,766 E. coli isolates were obtained for the evaluation. The target disinfection level was 200 CFU/100 ml, resulting in UV and PAA doses of 7 to 30 mJ/cm2 and 0.9 to 2.0 mg/liter, respectively. The proportions of UPECs were reduced in all samples after disinfection, with an average reduction by UV of 55% (range, 22% to 80%) and by PAA of 52% (range, 11% to 100%). Analysis of urovirulence genes revealed that the decline in the UPEC populations was not associated with any particular virulence factor. A positive association was found between the occurrence of urovirulence and antimicrobial resistance genes (ARGs). However, the changes in the prevalence of ARGs in potential UPECs were different following disinfection, i.e., UV appears to have had no effect, while PAA significantly reduced the ARG levels. Thus, this study showed that both UV and PAA disinfections reduced the proportion of UPECs and that PAA disinfection also reduced the proportion of antimicrobial resistance gene-carrying UPEC pathotypes in municipal wastewaters. PMID:24727265

Impact of UV and peracetic acid disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli in wastewater effluents.

Science.gov (United States)

Biswal, Basanta Kumar; Khairallah, Ramzi; Bibi, Kareem; Mazza, Alberto; Gehr, Ronald; Masson, Luke; Frigon, Dominic

2014-06-01

Wastewater discharges may increase the populations of pathogens, including Escherichia coli, and of antimicrobial-resistant strains in receiving waters. This study investigated the impact of UV and peracetic acid (PAA) disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli (UPEC), the most abundant E. coli pathotype in municipal wastewaters. Laboratory disinfection experiments were conducted on wastewater treated by physicochemical, activated sludge, or biofiltration processes; 1,766 E. coli isolates were obtained for the evaluation. The target disinfection level was 200 CFU/100 ml, resulting in UV and PAA doses of 7 to 30 mJ/cm(2) and 0.9 to 2.0 mg/liter, respectively. The proportions of UPECs were reduced in all samples after disinfection, with an average reduction by UV of 55% (range, 22% to 80%) and by PAA of 52% (range, 11% to 100%). Analysis of urovirulence genes revealed that the decline in the UPEC populations was not associated with any particular virulence factor. A positive association was found between the occurrence of urovirulence and antimicrobial resistance genes (ARGs). However, the changes in the prevalence of ARGs in potential UPECs were different following disinfection, i.e., UV appears to have had no effect, while PAA significantly reduced the ARG levels. Thus, this study showed that both UV and PAA disinfections reduced the proportion of UPECs and that PAA disinfection also reduced the proportion of antimicrobial resistance gene-carrying UPEC pathotypes in municipal wastewaters.

Cleaning, disinfection and sterilization of surface prion contamination.

Science.gov (United States)

McDonnell, G; Dehen, C; Perrin, A; Thomas, V; Igel-Egalon, A; Burke, P A; Deslys, J P; Comoy, E

2013-12-01

Prion contamination is a risk during device reprocessing, being difficult to remove and inactivate. Little is known of the combined effects of cleaning, disinfection and sterilization during a typical reprocessing cycle in clinical practice. To investigate the combination of cleaning, disinfection and/or sterilization on reducing the risk of surface prion contamination. In vivo test methods were used to study the impact of cleaning alone and cleaning combined with thermal disinfection and high- or low-temperature sterilization processes. A standardized test method, based on contamination of stainless steel wires with high titres of scrapie-infected brain homogenates, was used to determine infectivity reduction. Traditional chemical methods of surface decontamination against prions were confirmed to be effective, but extended steam sterilization was more variable. Steam sterilization alone reduced the risk of prion contamination under normal or extended exposure conditions, but did show significant variation. Thermal disinfection had no impact in these studies. Cleaning with certain defined formulations in combination with steam sterilization can be an effective prion decontamination process, in particular with alkaline formulations. Low-temperature, gaseous hydrogen peroxide sterilization was also confirmed to reduce infectivity in the presence and absence of cleaning. Prion decontamination is affected by the full reprocessing cycle used on contaminated surfaces. The correct use of defined cleaning, disinfection and sterilization methods as tested in this report in the scrapie infectivity assay can provide a standard precaution against prion contamination. Copyright © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Surface Disinfections: Present and Future

Directory of Open Access Journals (Sweden)

Matteo Saccucci

2018-01-01

Full Text Available The propagation of antibiotic resistance increases the chances of major infections for patients during hospitalization and the spread of health related diseases. Therefore finding new and effective solutions to prevent the proliferation of pathogenic microorganisms is critical, in order to protect hospital environment, such as the surfaces of biomedical devices. Modern nanotechnology has proven to be an effective countermeasure to tackle the threat of infections. On this note, recent scientific breakthroughs have demonstrated that antimicrobial nanomaterials are effective in preventing pathogens from developing resistance. Despite the ability to destroy a great deal of bacteria and control the outbreak of infections, nanomaterials present many other advantages. Moreover, it is unlikely for nanomaterials to develop resistance due to their multiple and simultaneous bactericidal mechanisms. In recent years, science has explored more complex antimicrobial coatings and nanomaterials based on graphene have shown great potential in antibacterial treatment. The purpose of this article is to deepen the discussion on the threat of infections related to surface disinfection and to assess the state of the art and potential solutions, with specific focus on disinfection procedures using nanomaterials.

Health impact of disinfection by-products in swimming pools

Directory of Open Access Journals (Sweden)

Cristina M. Villanueva

2012-12-01

Full Text Available This article is focused on the epidemiological evidence on the health impacts related to disinfection by-products (DBPs in swimming pools, which is a chemical hazard generated as an undesired consequence to reduce the microbial pathogens. Specific DBPs are carcinogenic, fetotoxic and/or irritant to the airways according to experimental studies. Epidemiological evidence shows that swimming in pools during pregnancy is not associated with an increased risk of reproductive outcomes. An epidemiological study suggested an increased risk of bladder cancer with swimming pool attendance, although evidence is inconclusive. A higher prevalence of respiratory symptoms including asthma is found among swimming pool workers and elite swimmers, although the causality of this association is unclear. The body of evidence in children indicates that asthma is not increased by swimming pool attendance. Overall, the available knowledge suggests that the health benefits of swimming outweigh the potential health risks of chemical contamination. However, the positive effects of swimming should be enhanced by minimising potential risks.

An EPR study on wastewater disinfection by peracetic acid, hydrogen peroxide and UV irradiation.

Science.gov (United States)

Bianchini, Roberto; Calucci, Lucia; Caretti, Cecilia; Lubello, Claudio; Pinzino, Calogero; Piscicelli, Michela

2002-09-01

EPR spectroscopy was applied to obtain qualitative and quantitative information on the radicals produced in disinfection processes of wastewater for agricultural reuse. The DEPMPO spin trap was employed to detect hydroxyl and carbon-centered short living radicals in two different peracetic acid solutions and a hydrogen peroxide solution used for water disinfection either in the absence or in the presence of UV-C irradiation. Moreover, three different kinds of water (wastewater, demineralized water, distilled water) were analysed in order to assess the contribution of Fenton reactions to the radical production. The spectroscopic results were discussed in relation to the efficiency of the different oxidizing agents and UV irradiation in wastewater disinfection evaluated as Escherichia Coli, Faecal and Total Coliforms inactivation.

Practical disinfection chemicals for fishing and crayfishing gear against crayfish plague transfer

Directory of Open Access Journals (Sweden)

Jussila J.

2014-01-01

Full Text Available We tested four commercial disinfectants against crayfish plague (Aphanomyces astaci spores in both aquatic solutions and with material mimicking fishing and crayfishing gear, e.g. traps, ropes, mesh, etc. The tested disinfectants were Proxitane®5:14, Proxitane®12:20, Wofasteril®E400, Virkon®S and hydrogen peroxide. The effects of the chemicals were initially tested in liquid zoospore cultures and the effective concentrations were then further tested using clean and dirty model materials (PP sheet, nylon rope, cotton fabric contaminated with A. astaci spore solutions. The disinfectants effective against infective crayfish plague spores with both clean and dirty model materials were Proxinate®5:14 (effective concentration was 30 mg·L-1 of PAA and Virkon®S (3 g·L-1, while Proxinate®12:20 (10 mg·L-1 of PAA and Wofasteril®E400 (30 mg·L-1 of PAA worked only with clean model materials. Hydrogen peroxide was not effective in the tested concentrations and conditions. Based on the results, the disinfectants most suitable for the fishing and crayfishing gear disinfection would be Proxitane®5:14 and Virkon®S, with the condition that all the gear should be thoroughly cleaned of organic matter to ensure inactivation of A. astaci spores.

Overcoming the problem of residual microbial contamination in dental suction units left by conventional disinfection using novel single component suction handpieces in combination with automated flood disinfection.

Science.gov (United States)

Boyle, M A; O'Donnell, M J; Russell, R J; Galvin, N; Swan, J; Coleman, D C

2015-10-01

cannot be adequately disinfected without disassembly, which is costly in time, staff and resources. The automated STCS DCU suction disinfection system used with single component handpieces provides an effective solution. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Carbon nanoparticles for solar disinfection of water.

Science.gov (United States)

Maddigpu, Pratap Reddy; Sawant, Bhairavi; Wanjari, Snehal; Goel, M D; Vione, Davide; Dhodapkar, Rita S; Rayalu, S

2018-02-05

The present manuscript deals with the application of carbon nano particles (CNP) and chitosan (CHIT) in the form of CHIT-CNP composite for the disinfection of water. The CHIT-CNP composite was prepared by the solution casting method and characterized by TEM, XRD and elemental analysis. In the present investigation we study the disinfection efficiency towards E. coli bacteria of both CNP and CHIT-CNP, under sunlight (SODIS) in identical experimental conditions. Both CNP and CHIT-CNP enhanced disinfection as compared to SODIS alone, and comparable performance was achieved when the same dose of CNP in the two materials was applied. However, the CHIT-CNP composite is in the form of a fabric and it is easier to use and handle as compared to the CNP powder, especially in rural and resource-constrained areas. Moreover the SODIS-CHIT-CNP setup, when used in a compound parabolic collector (CPC) reactor showed high bactericidal efficiency compared to SODIS alone, which is promising for practical applications. The disinfection potential of the CNP powder was compared with that of the well-known material TiO 2 Degussa P25 (DP 25 ): DP 25 gave 6-log kill of bacteria in 180min, whereas CNP produced 6-log kill in 150min. Copyright © 2017. Published by Elsevier B.V.

Effectiveness of alcohol-based hand disinfectants in a public administration: Impact on health and work performance related to acute respiratory symptoms and diarrhoea

Directory of Open Access Journals (Sweden)

Hübner Nils-Olaf

2010-08-01

Full Text Available Abstract Background The economical impact of absenteeism and reduced productivity due to acute infectious respiratory and gastrointestinal disease is normally not in the focus of surveillance systems and may therefore be underestimated. However, large community studies in Europe and USA have shown that communicable diseases have a great impact on morbidity and lead to millions of lost days at work, school and university each year. Hand disinfection is acknowledged as key element for infection control, but its effect in open, work place settings is unclear. Methods Our study involved a prospective, controlled, intervention-control group design to assess the epidemiological and economical impact of alcohol-based hand disinfectants use at work place. Volunteers in public administrations in the municipality of the city of Greifswald were randomized in two groups. Participants in the intervention group were provided with alcoholic hand disinfection, the control group was unchanged. Respiratory and gastrointestinal symptoms and days of work were recorded based on a monthly questionnaire over one year. On the whole, 1230 person months were evaluated. Results Hand disinfection reduced the number of episodes of illness for the majority of the registered symptoms. This effect became statistically significant for common cold (OR = 0.35 [0.17 - 0.71], p = 0.003, fever (OR = 0.38 [0.14-0.99], p = 0.035 and coughing (OR = 0.45 [0.22 - 0.91], p = 0.02. Participants in the intervention group reported less days ill for most symptoms assessed, e.g. colds (2.07 vs. 2.78%, p = 0.008, fever (0.25 vs. 0.31%, p = 0.037 and cough (1.85 vs. 2.00%, p = 0.024. For diarrhoea, the odds ratio for being absent became statistically significant too (0.11 (CI 0.01 - 0.93. Conclusion Hand disinfection can easily be introduced and maintained outside clinical settings as part of the daily hand hygiene. Therefore it appears as an interesting, cost-efficient method within the scope

Effectiveness of alcohol-based hand disinfectants in a public administration: impact on health and work performance related to acute respiratory symptoms and diarrhoea.

Science.gov (United States)

Hübner, Nils-Olaf; Hübner, Claudia; Wodny, Michael; Kampf, Günter; Kramer, Axel

2010-08-24

The economical impact of absenteeism and reduced productivity due to acute infectious respiratory and gastrointestinal disease is normally not in the focus of surveillance systems and may therefore be underestimated. However, large community studies in Europe and USA have shown that communicable diseases have a great impact on morbidity and lead to millions of lost days at work, school and university each year. Hand disinfection is acknowledged as key element for infection control, but its effect in open, work place settings is unclear. Our study involved a prospective, controlled, intervention-control group design to assess the epidemiological and economical impact of alcohol-based hand disinfectants use at work place. Volunteers in public administrations in the municipality of the city of Greifswald were randomized in two groups. Participants in the intervention group were provided with alcoholic hand disinfection, the control group was unchanged. Respiratory and gastrointestinal symptoms and days of work were recorded based on a monthly questionnaire over one year. On the whole, 1230 person months were evaluated. Hand disinfection reduced the number of episodes of illness for the majority of the registered symptoms. This effect became statistically significant for common cold (OR = 0.35 [0.17 - 0.71], p = 0.003), fever (OR = 0.38 [0.14-0.99], p = 0.035) and coughing (OR = 0.45 [0.22 - 0.91], p = 0.02). Participants in the intervention group reported less days ill for most symptoms assessed, e.g. colds (2.07 vs. 2.78%, p = 0.008), fever (0.25 vs. 0.31%, p = 0.037) and cough (1.85 vs. 2.00%, p = 0.024). For diarrhoea, the odds ratio for being absent became statistically significant too (0.11 (CI 0.01 - 0.93). Hand disinfection can easily be introduced and maintained outside clinical settings as part of the daily hand hygiene. Therefore it appears as an interesting, cost-efficient method within the scope of company health support programmes. ISRCTN96340690.

Assessment of peracetic acid disinfected effluents by microbiotests.

Science.gov (United States)

Antonelli, M; Mezzanotte, V; Panouillères, M

2009-09-01

Bioassays were performed by commercially available kits on peracetic acid (PAA) solutions, at different concentrations, and on secondary effluents (from two different wastewater treatment plants) after disinfection at bench-scale, considering both samples containing residual active PAA and the same samples where residual PAA was quenched. Four indicator organisms were used: Vibrio fischeri, Thamnocephalus platyurus, Daphnia magna, and Selenastrum capricornutum. The experiments lead to conclude that Thamnocephalus platyurus is a very sensitive organism, probably not adequate to perform a reliable toxicity assessment of effluents for monitoring purposes. The presence of specific organic compounds deriving from human metabolism and urban pollution, even at very low concentrations, can affect the results of bioassays, especially those performed on Vibrio fischeri. PAA is toxic for bacteria and crustaceans even at concentrations lower than the ones commonly used in wastewater disinfection (2-5 mg/L), while its effect on algae is smaller. The toxic effect on bacteria was expected, as PAA is used for disinfection, but its possible influence on biological processes in the receiving aquatic environment should be considered. Toxicity on crustaceans would confirm the fact that discharging disinfected effluents could raise some environmental problems.

Surface disinfection tests with Salmonella and a putative indicator bacterium, mimicking worst-case scenarios in poultry houses

DEFF Research Database (Denmark)

Gradel, K.O.; Sayers, A.R.; Davies, R.H.

2004-01-01

Surface disinfection studies mimicking worst-case scenarios in badly cleaned poultry houses were made with 3 bacterial isolates (Salmonella enteritidis, Salmonella senftenberg, and Enterococcus faecalis), and 3 1% disinfectant solutions, formaldehyde (F; 24.5% vol/vol), glutaraldehyde...... hard water, except when feed chain links with fats were disinfected using 30degreesC before and after disinfection, for which the peroxygen compound seemed more effective. Enterococcus faecalis was equally or less susceptible than S. enteritidis and S. senftenberg, indicating its suitability...... as an indicator bacterium. For the peroxygen compound, S. senftenberg was more susceptible than S. enteritidis in spite of higher minimum inhibitory concentrations to this disinfectant for the former....

Recent advances in drinking water disinfection: successes and challenges.

Science.gov (United States)

Ngwenya, Nonhlanhla; Ncube, Esper J; Parsons, James

2013-01-01

, it is recommended that water disinfection should never be compromised by attempting to control DBPs. The reason for this is that the risks of human illness and death from pathogens in drinking water are much greater than the risks from exposure to disinfectants and disinfection by-products. Nevertheless, if DBP levels exceed regulatory limits, strategies should focus on eliminating organic impurities that foster their formation, without compromising disinfection. As alternatives to chlorine, disinfectants such as chloramines, ozone, chlorine dioxide, and UV disinfection are gaining popularity. Chlorine and each of these disinfectants have individual advantage and disadvantage in terms of cost, efficacy-stability, ease of application, and nature of disinfectant by-products (DBPs). Based on efficiency, ozone is the most efficient disinfectant for inactivating bacteria, viruses, and protozoa. In contrast, chloramines are the least efficient and are not recommended for use as primary disinfectants. Chloramines are favored for secondary water disinfection, because they react more slowly than chlorine and are more persistent in distribution systems. In addition, chloramines produce lower DBP levels than does chlorine, although microbial activity in the distribution system may produce nitrate from monochloramine, when it is used as a residual disinfectant, Achieving the required levels of water quality, particularly microbial inactivation levels, while minimizing DBP formation requires the application of proper risk and disinfection management protocols. In addition, the failure of conventional treatment processes to eliminate critical waterborne pathogens in drinking water demand that improved and/or new disinfection technologies be developed. Recent research has disclosed that nanotechnology may offer solutions in this area, through the use of nanosorbents, nanocatalysts, bioactive nanoparticles, nanostructured catalytic membranes, and nanoparticle-enhanced filtration.

40 CFR 141.72 - Disinfection.

Science.gov (United States)

2010-07-01

... PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.72 Disinfection. A public water... the direct influence of surface water and provides filtration treatment must provide disinfection...) Disinfection requirements for public water systems which provide filtration. Each public water system that...

Solutions for care of silicone hydrogel lenses.

Science.gov (United States)

Willcox, Mark D P

2013-01-01

During wear of contact lenses on a daily wear basis, it is necessary to disinfect the lens overnight before reinserting the lens the next day. The ability of the solutions used for this to disinfect lenses and lens cases is important for safe lens wear. The literature on the disinfecting ability of multipurpose disinfecting solutions (MPDS) commonly used with silicone hydrogel lenses reported during the period 2000 to 2012 is reviewed, as this is the period of time during which these lenses have been commercially available. Particular emphasis is placed on the ability of disinfecting solutions to control colonization of lens cases by microbes and changes in composition and use of the solutions. In addition, the literature is reviewed on ways of minimizing lens case microbial contamination. Maintaining the hygiene of contact lenses and lens cases is important in minimizing various forms of corneal infiltrative events that occur during lens wear. Although lens case contamination is not associated with different lenses, it is determined by use of different MPDS. MPDS that allow more frequent or heavy contamination of cases by Gram-negative bacteria are associated with a higher incidence of corneal infiltrative events. MPDS are now available that contain dual disinfectants. Wiping lens cases with tissues or using lens cases that incorporate silver are associated with reductions in contamination in clinical trials. Similarly, using MPDS to rub and rinse lenses before disinfection may reduce levels of microbes on lenses. The MPDS also contain surfactants that help reduce deposition and denaturation of proteins on lenses. Improvements in MPDS formulations and hygiene practices may help to reduce the incidence of adverse events that are seen during use with silicone hydrogel lenses.

Electrochemically activated water as an alternative to chlorine for decentralized disinfection

KAUST Repository

Ghebremichael, Kebreab A.

2011-06-01

Electrochemically activated (ECA) water is being extensively studied and considered as an alternative to chlorine for disinfection. Some researchers claim that ECA is by and large a chlorine solution, while others claim the presence of reactive oxygen species such as ozone and hydroxyl radicals in addition to chlorine. This study compares sodium hypochlorite (NaOCl) and ECA in terms of disinfection efficacy, trihalomethanes (THMs) formation, stability and composition. The studies were carried out under different process conditions (pH 5,7 and 9, disinfectant concentrations of 2-5 mg/L and dissolved organic carbon (DOC) concentration of 2-4 mg/L). The results indicated that in the presence of low DOC (<2 mg/L) ECA showed better disinfection efficacy for Escherichia coli inactivation, formed lower THM and had better stability compared with NaOCl at both pH 5 and 7. Stability studies of stock solutions showed that over a period of 30 days, ECA decayed by only 5% while NaOCl decayed by 37.5% at temperatures of 4 °C. In a fresh ECA of 200 mg/L chlorine, about 5.3 mg/L ozone and 36.9 mg/L ClO2 were detected. The study demonstrates that ECA could be a suitable alternative to NaOCl where decentralized production and use are required. © IWA Publishing 2011.

Spiral-shaped disinfection reactors

KAUST Repository

Ghaffour, NorEddine; Ait-Djoudi, Fariza; Naceur, Wahib Mohamed; Soukane, Sofiane

2015-01-01

This disclosure includes disinfection reactors and processes for the disinfection of water. Some disinfection reactors include a body that defines an inlet, an outlet, and a spiral flow path between the inlet and the outlet, in which the body

A review on wastewater disinfection

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Mohammad Mehdi Amin

2013-01-01

Full Text Available Changes in regulations and development of new technologies have affected the selection of alternative for treated wastewater disinfection. Disinfection is the last barrier of wastewater reclamation process to protect ecosystem safety and human health. Driving forces include water scarcity and drinking water supply, irrigation, rapid industrialization, using reclaimed water, source protection, overpopulation, and environmental protection. The safe operation of water reuse depends on effluent disinfection. Understanding the differences in inactivation mechanisms is critical to identify rate-limiting steps involved in the inactivation process as well as to develop more effective disinfection strategies. Disinfection byproducts discharged from wastewater treatment plants may impair aquatic ecosystems and downstream drinking-water quality. Numerous inorganic and organic micropollutants can undergo reactions with disinfectants. Therefore, to mitigate the adverse effects and also to enhance that efficiency, the use of alternative oxidation/disinfection systems should be evaluated as possible alternative to chlorine. This review gives a summary of the traditional, innovative, and combined disinfection alternatives and also disinfection byproducts for effluent of municipal wastewater treatment plants.

Can pulsed xenon ultraviolet light systems disinfect aerobic bacteria in the absence of manual disinfection?

Science.gov (United States)

Jinadatha, Chetan; Villamaria, Frank C; Ganachari-Mallappa, Nagaraja; Brown, Donna S; Liao, I-Chia; Stock, Eileen M; Copeland, Laurel A; Zeber, John E

2015-04-01

Whereas pulsed xenon-based ultraviolet light no-touch disinfection systems are being increasingly used for room disinfection after patient discharge with manual cleaning, their effectiveness in the absence of manual disinfection has not been previously evaluated. Our study indicates that pulsed xenon-based ultraviolet light systems effectively reduce aerobic bacteria in the absence of manual disinfection. These data are important for hospitals planning to adopt this technology as adjunct to routine manual disinfection. Published by Elsevier Inc.

Control of house-dust mites with home disinfectants

NARCIS (Netherlands)

Schober, G.; Wetter, G.; Bischoff, E.; Bronswijk, van J.E.M.H.; Kniest, F.M.

1987-01-01

Chemical disinfectants and biocidal preparations used in households were tested in the laboratory for their ability to kill the house-dust miteDermatophagoides farinae. Batches of ten specimens were soaked in aqueous solutions or suspensions containing 0.0, 0.1, 0.3, 1.0, 3.0 and 10.0% (by volume)

Ultraviolet (UV) disinfection of grey water: particle size effects.

Science.gov (United States)

Winward, G P; Avery, L M; Stephenson, T; Jefferson, B

2008-02-01

The impact of water quality on the ultraviolet (UV) disinfection of grey water was investigated with reference to urban water reuse. Direct UV disinfection of grey water did not meet the stringent California State Title 22 criteria for unrestricted urban water reuse due to the presence of particulate material ranging from or = 2000 microm in size. Grey water was manipulated by settling to produce fractions of varying particle size distributions and blending was employed post-disinfection to extract particle-associated coliforms (PACs). The efficacy of UV disinfection was found to be linked to the particle size of the grey water fractions. The larger particle size fractions with a mean particle size of 262 microm and above were observed to shield more coliforms from UV light than did the smaller particles with a mean particle size below 119 microm. Up to 70% of total coliforms in the larger particle size fractions were particle-associated following a UV dose (fluence) of 260 mJ.cm(-2) and would remain undetected by standard coliform enumeration techniques. Implications for urban water reuse are discussed and recommendations made for grey water treatment to ensure removal of particle-associated indicator bacteria and pathogens prior to UV disinfection.

Use of photoactivated disinfection and platelet-rich fibrin in regenerative Endodontics

Science.gov (United States)

Johns, Dexton Antony; Shivashankar, Vasundara Yayathi; Krishnamma, Shoba; Johns, Manu

2014-01-01

Aim: Photoactivated disinfection has been used as an adjunct to conventional endodontic treatment. Its use in regenerative endodontics is not reported in literature. The aim of this case report was to describe a new proposal for pulp revascularization with disinfection of pulp canal space using a unique combination of a photosensitizer solution and low-power laser light. Materials and Methods: A 9-year-old boy came with the chief complaint of discolored upper central incisors (#8, #9). A diagnosis of pulp necrosis was made on the basis of clinical and radiographic findings. The canal was irrigated with 5.25% sodium hypochlorite solution and dried with paper points. Photodynamic therapy was used to disinfect the root canal and platelet-rich fibrin was used to revitalize the pulp. Three millimeters of gray mineral trioxide aggregate was placed directly over the platelet-rich plasma clot. Three days later, the tooth was double-sealed with permanent filling materials. Results: Clinical examination revealed no sensitivity to percussion or palpation tests. Radiograph revealed continued thickening of the dentinal walls, root lengthening, regression of the peri-apical lesion and apical closure. Both the roots showed complete apical closure at the 10-month follow-up. However, the teeth were not responsive to electric pulp test. Conclusion: This report of pulp revascularization shows that disinfection with photodynamic therapy combined with platelet-rich fibrin leads to satisfactory root development in necrotic immature teeth. PMID:25298655

[Disinfectants and main sanitary and preventive measures for protection of ventilation and air-conditioning systems from Legionella contamination].

Science.gov (United States)

Gerasimov, V N; Golov, E A; Khramov, M V; Diatlov, I A

2008-01-01

The study was devoted to selection and assessment of disinfecting preparations for prevention of contamination by Legionella. Using system of criteria for quality assessment of disinfectants, seven newdomestic ones belonging to quaternary ammonium compounds class or to oxygen-containing preparations and designed for disinfecting of air-conditioning and ventilation systems were selected. Antibacterial and disinfecting activities of working solutions of disinfectants were tested in laboratory on the test-surfaces and test-objects of premises' air-conditioning and ventilation systems contaminated with Legionella. High antimicrobial and disinfecting activity of new preparations "Dezactiv-M", "ExtraDez", "Emital-Garant", "Aquasept Plus", "Samarovka", "Freesept", and "Ecobreeze Oxy" during their exposure on objects and materials contaminated with Legionella was shown. Main sanitary and preventive measures for defending of air-conditioning and ventilation systems from contamination by Legionella species were presented.

A bacteriological study of hospital beds before and after disinfection with phenolic disinfectant

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Andrade Denise de

2000-01-01

Full Text Available In hospitals, one of the ways to control microbial contamination is by disinfecting the furniture used by patients. This study's main objective was to evaluate the microbiological condition of hospital mattresses before and after such disinfection, in order to identify bacteria that are epidemiologically important in nosocomial infection, such as Staphylococcus aureus and Pseudomonas aeruginosa. RODAC plates with two different culture media were used to collect specimens. Patient beds were selected according to previously established criteria, and surface areas on the mattresses were chosen at random. From the total of 1 040 plate cultures from 52 mattresses, positive results were obtained from 500 of them (48.1%, 263 before disinfection and 237 after disinfection. Considering the selectivity of the culture media, the positivity rate was high. There were high prevalences of S. aureus both before and after mattress disinfection. The study results suggest that the usual disinfection procedures, instead of diminishing the number of microbes, merely displace them from one part of the mattress to another, and the number of microorganisms remains the same.

A bacteriological study of hospital beds before and after disinfection with phenolic disinfectant

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Denise de Andrade

2000-03-01

Full Text Available In hospitals, one of the ways to control microbial contamination is by disinfecting the furniture used by patients. This study's main objective was to evaluate the microbiological condition of hospital mattresses before and after such disinfection, in order to identify bacteria that are epidemiologically important in nosocomial infection, such as Staphylococcus aureus and Pseudomonas aeruginosa. RODAC plates with two different culture media were used to collect specimens. Patient beds were selected according to previously established criteria, and surface areas on the mattresses were chosen at random. From the total of 1 040 plate cultures from 52 mattresses, positive results were obtained from 500 of them (48.1%, 263 before disinfection and 237 after disinfection. Considering the selectivity of the culture media, the positivity rate was high. There were high prevalences of S. aureus both before and after mattress disinfection. The study results suggest that the usual disinfection procedures, instead of diminishing the number of microbes, merely displace them from one part of the mattress to another, and the number of microorganisms remains the same.

Patient satisfaction with a novel one-step hydrogen peroxide solution

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Schafer J

2014-10-01

Full Text Available Jeffery Schafer, Robert Steffen, Marjorie J Rah Bausch & Lomb Incorporated, Rochester, NY, USA Purpose: We aimed to evaluate the product performance of a novel one-step hydrogen ­peroxide cleaning and disinfecting solution, PeroxiClear (“Test” solution, when used by habitual Clear Care users to bilaterally clean and disinfect their soft contact lenses, for approximately 2 weeks.Methods: This was a 2-week, open-label, bilateral eye study designed to include subjects ­ranging in age from 18 to 55 years, inclusive. All subjects were habitual users of the Clear Care peroxide regimen for cleaning, disinfecting, and storage of their soft contact lenses, for at least 6 months prior to enrolling in the study. Subjects were examined at two study visits: a screening/­dispensing visit and a 2-week follow-up visit. The primary end point, patient preference for the Test solution, was evaluated with an online survey administered after 7 days of using the Test cleaning and disinfecting solution. Respondents could answer questions with neutral or nonneutral responses (better or worse. Statistical analyses were conducted to compare differences for nonneutral responses.Results: Of the 299 eligible subjects enrolled, 297 completed the study, conducted at 21 sites by 21 investigators in the United States. A significantly higher proportion of nonneutral respondents reported the Test solution was better overall (85.9% than their habitual contact lens solution (14.1% (P<0.001. The proportion of subjects who preferred the Test solution over their habitual solution was significantly higher for each of the preference questions regarding comfort (85.4% vs 14.6%, moistness (90.0% vs 10.0%, cleanness (91.6% vs 8.4%, and clarity of vision (85.8% vs 14.2%.Conclusion: After 7 days of using the Test cleaning and disinfecting solution, survey results indicated high levels of patient satisfaction and preference over the habitual solution, particularly in the areas of

Tolerance of Clostridium perfringens biofilms to disinfectants commonly used in the food industry.

Science.gov (United States)

Charlebois, Audrey; Jacques, Mario; Boulianne, Martine; Archambault, Marie

2017-04-01

Clostridium perfringens is an opportunistic pathogen that can cause food poisoning in humans and various enterotoxemia in animal species. Recently, it was shown to form mono-species biofilms, a structured community of bacterial cells enclosed in a self-produced extracellular matrix. Biofilms have been associated with tolerance to antibiotics, disinfectants, and physical and environmental stresses. Very little is known about the tolerance of C. perfringens biofilm toward disinfectants. In the present study, susceptibilities of C. perfringens biofilms to five types of commonly used disinfectants on farms and in food processing environments were analysed. In this paper, we show that C. perfringens mono-species biofilms can protect the bacterial cells from the action of potassium monopersulfate, quaternary ammonium chloride, hydrogen peroxide and glutaraldehyde solutions. However, sodium hypochlorite solution was shown to be effective on C. perfringens biofilms. Our investigation of dual-species biofilms of C. perfringens with the addition of Staphylococcus aureus or Escherichia coli demonstrated that overall, the mono-species biofilm of C. perfringens was more tolerant to all disinfectants than the dual-species biofilms. For the anaerobic grown biofilms, the mono-species biofilm of C. perfringens was more tolerant to sodium hypochlorite and quaternary ammonium chloride than the dual-species biofilms of C. perfringens with S. aureus or E. coli. This study demonstrates that C. perfringens biofilm is an effective protection mechanism to disinfectants commonly used on farms and in food processing environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Electrochemically activated water as an alternative to chlorine for decentralized disinfection

KAUST Repository

Ghebremichael, Kebreab A.; Muchelemba, E.; Petruševski, Branislav; Amy, Gary L.

2011-01-01

Electrochemically activated (ECA) water is being extensively studied and considered as an alternative to chlorine for disinfection. Some researchers claim that ECA is by and large a chlorine solution, while others claim the presence of reactive

Evaluation of properties of irreversible hydrocolloid impression materials mixed with disinfectant liquids

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Arul Amalan

2013-01-01

Conclusion: Chlorhexidine solution can be used to mix irreversible hydrocolloid impression materials in regular dental practice as it did not significantly alter the properties. This may ensure effective disinfection of impressions.

Comparing the disinfecting efficacies of Micro 10, Deconex, Alprocid and Microzid af on the microorganisms on radiographic equipments

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Zahed Mohammadi

2008-08-01

Full Text Available Background and aims. The exposure and processing of dental radiographs are not routinely associated with the spatter of blood or saliva; however, infection control is still an issue resulting from contaminated equipment, supplies, film packets or cassettes. This study aimed at comparing the efficacy of four commercially available disinfectants on microorganisms present on the equipment of radiology department. Materials and methods. Samples from twelve sites of the radiology department were collected using a sterile swab smeared with normal saline, which was then dipped in a test tube. Experimental surfaces were then disinfected by the spray-wipe-spray method using one of Micro 10, Deconex, Alprocid or Microzid AF disinfectants, followed by resampling. The samples were subsequently cultured on blood agar and EMB plates and the colonies were counted. Isolates were identified by biochemical tests. For statistical analysis, Wilcoxon signed ranks test, Kruskal-Wallis, Chi-square and Fisher exact tests were used. Results. Staphylococcus aureus and coagulase-negative staphylococci had the highest and Lactobacillus spp. had the lowest prevalence before disinfection. There were significant differences between the cfu/mL of bacteria before and after disinfection with any of the four disinfectant solutions. There was a significant difference between efficacy of Deconex and Alprocid (P = 0.014, Deconex and Microzid AF (P = 0.001, and Deconex and Micro 10 (P = 0.001. Conclusion. According to the results, Deconex has the highest disinfectant efficacy compared to other solutions.

Estimating retrospective exposure of household humidifier disinfectants.

Science.gov (United States)

Park, D U; Friesen, M C; Roh, H S; Choi, Y Y; Ahn, J J; Lim, H K; Kim, S K; Koh, D H; Jung, H J; Lee, J H; Cheong, H K; Lim, S Y; Leem, J H; Kim, Y H; Paek, D M

2015-12-01

We conducted a comprehensive humidifier disinfectant exposure characterization for 374 subjects with lung disease who presumed their disease was related to humidifier disinfectant use (patient group) and for 303 of their family members (family group) for an ongoing epidemiological study. We visited the homes of the registered patients to investigate disinfectant use characteristics. Probability of exposure to disinfectants was determined from the questionnaire and supporting evidence from photographs demonstrating the use of humidifier disinfectant, disinfectant purchase receipts, any residual disinfectant, and the consistency of their statements. Exposure duration was estimated as cumulative disinfectant use hours from the questionnaire. Airborne disinfectant exposure intensity (μg/m(3)) was estimated based on the disinfectant volume (ml) and frequency added to the humidifier per day, disinfectant bulk level (μg/ml), the volume of the room (m(3)) with humidifier disinfectant, and the degree of ventilation. Overall, the distribution patterns of the intensity, duration, and cumulative exposure to humidifier disinfectants for the patient group were higher than those of the family group, especially for pregnant women and patients ≤6 years old. Further study is underway to evaluate the association between the disinfectant exposures estimated here with clinically diagnosed lung disease. Retrospective exposure to household humidifier disinfectant as estimated here can be used to evaluate associations with clinically diagnosed lung disease due to the use of humidifier disinfectant in Korea. The framework, with modifications to account for dispersion and use patterns, can also be potentially adapted to assessment of other household chemical exposures. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

[Complex technology for water and wastewater disinfection and its industrial realization in prototype unit].

Science.gov (United States)

Arakcheev, E N; Brunman, V E; Brunman, M V; Konyashin, A V; Dyachenko, V A; Petkova, A P

Usage of complex automated electrolysis unit for drinking water disinfection and wastewater oxidation and coagulation is scoped, its ecological and energy efficiency is shown. Properties of technological process of anolyte production using membrane electrolysis of brine for water disinfection in municipal pipelines and potassium ferrate production using electrochemical dissolution of iron anode in NaOH solution for usage in purification plants are listed. Construction of modules of industrial prototype for anolyte and ferrate production and applied aspects of automation of complex electrolysis unit are proved. Results of approbation of electrolytic potassium ferrate for drinking water disinfection and wastewater, rain water and environmental water oxidation and coagulation are shown.

Two in-vivo protocols for testing virucidal efficacy of handwashing and hand disinfection.

Science.gov (United States)

Steinmann, J; Nehrkorn, R; Meyer, A; Becker, K

1995-01-01

Whole-hands and fingerpads of seven volunteers were contaminated with poliovirus type 1 Sabin strain in order to evaluate virucidal efficacy of different forms of handwashing and handrub with alcohols and alcohol-based disinfectants. In the whole-hand protocol, handwashing with unmedicated soap for 5 min and handrubbing with 80% ethanol yielded a log reduction factor (RF) of > 2, whereas the log RF by 96.8% ethanol exceeded 3.2. With the fingerpad model ethanol produced a greater log RF than iso- or n-propanol. Comparing five commercial hand disinfectants and a chlorine solution (1.0% chloramine T-solution) for handrub, Desderman and Promanum, both composed of ethanol, yielded log RFs of 2.47 and 2.26 respectively after an application time of 60 s, similar to 1.0% chloramine T-solution (log RF of 2.28). Autosept, Mucasept, and Sterillium, based on n-propanol and/or isopropanol, were found to be significantly less effective (log RFs of 1.16, 1.06 and 1.52 respectively). A comparison of a modified whole-hand and the fingerpad protocol with Promanum showed similar results with the two systems suggesting both models are suitable for testing the in-vivo efficacy of handwashing agents and hand disinfectants which are used without any water.

Generation of ozone foam and its application for disinfection

Science.gov (United States)

Hiragaki, Keisuke; Ishimaru, Tomiya; Nakanishi, Masaru; Muraki, Ryouji; Nieda, Masanori; Yamabe, Chobei

2015-07-01

Generated ozone foam was applied to the disinfection of Pseudomonas fluorescens. The effect of disinfection has been confirmed experimentally and new equipment for the disinfection of hands using this ozone foam has been put on the market for the practical use. The ozone foam was produced in the foam generator after mixing the water including surfactant (30 mL/min) and air including ozone (1000 ppm = 2.14 g/m3 ~ 1600 ppm = 3.4 g/m3, 300 mL/min). The liquid-to-gas ratio is 100 L/m3. The concentration of dissolved ozone in the thin liquid films of the bubbles was about 3 mg/L which was measured by the chemical method of the KI absorption and titration of sodium thiosulfate solution. The disinfection test samples were prepared using the PET disk on which Pseudomonas fluorescens of its number of more than 108 were attached. Test sample was inserted into ozone foam set on the glass plate for one to 6 min. The survival rate log (N/N0 decreased with time and its value of about-2.6 (i.e., ~1/400) was obtained at 6 min (2 min × 3 times repeated). It was also confirmed that the ozone foam was useful for the disinfection of hands. For more effective disinfection (in case of taking a long time for foam melting), the ozone foam was broken by force and changed into ozone water by which the survival rate decreased ×4 (i.e., N/N0 = 1/10 000) at 4 ~ 6 min. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

Applications of Photocatalytic Disinfection

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Joanne Gamage

2010-01-01

Full Text Available Due to the superior ability of photocatalysis to inactivate a wide range of harmful microorganisms, it is being examined as a viable alternative to traditional disinfection methods such as chlorination, which can produce harmful byproducts. Photocatalysis is a versatile and effective process that can be adapted for use in many applications for disinfection in both air and water matrices. Additionally, photocatalytic surfaces are being developed and tested for use in the context of “self-disinfecting” materials. Studies on the photocatalytic technique for disinfection demonstrate this process to have potential for widespread applications in indoor air and environmental health, biological, and medical applications, laboratory and hospital applications, pharmaceutical and food industry, plant protection applications, wastewater and effluents treatment, and drinking water disinfection. Studies on photocatalytic disinfection using a variety of techniques and test organisms are reviewed, with an emphasis on the end-use application of developed technologies and methods.

Evaluating Environmental Persistence and Disinfection of the Ebola Virus Makona Variant

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Bradley W. M. Cook

2015-04-01

Full Text Available Background: The current disease outbreak caused by the Ebola virus Makona variant (EBOV/Mak has led to unprecedented morbidity and lethality given its geographic reach and sustained transmission. Sodium hypochlorite and ethanol are well-accepted decontamination agents, however little published evidence supports the selection of appropriate concentrations and contact times. The present study addresses the environmental robustness of EBOV/Mak and evaluates the effectiveness of sodium hypochlorite and ethanol as disinfectants. Methods: EBOV/Mak was suspended in a simulated organic soil load and dried onto surfaces. Viability was measured at 1 hour, 24 hours, 72 hours, and 192 hours. For the evaluation of disinfectants, EBOV/Mak in a simulated organic soil was dried onto stainless steel carriers and disinfected with 0.01% (v/v, 0.1% (v/v, 0.5% (v/v and 1% (v/v sodium hypochlorite solutions or 67% (v/v ethanol at contact times of 1, 5 or 10 minutes. Results: EBOV/Mak persisted longer on steel and plastic surfaces (192 hours than cotton (<24 hours. Dilute sodium hypochlorite (0.01% and 0.1% showed little antiviral action, whereas 0.5% and 1% sodium hypochlorite solutions demonstrated recoverable virus at one minute but sterilized surfaces in five minutes. Disinfection with 67% ethanol did not fully clear infectious virions from 3/9 carriers at 1 minute but sterilized all carriers at 5 and 10 minutes. Conclusions: Sodium hypochlorite and ethanol effectively decontaminate EBOV/Mak suspended in a simulated organic load; however, selection of concentration and contact time proves critical.

Effectiveness of 2% peracetic acid for the disinfection of gutta-percha cones

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Ana Carolina Rodrigues Danzi Salvia

2011-02-01

Full Text Available The aim of this study was to evaluate the effectiveness of 2% peracetic acid for the disinfection of gutta-percha cones contaminated in vitro with Escherichia coli, Staphylococcus aureus, Streptococcus mutans, Candida albicans and Bacillus subtilus (in spore form. Two hundred and twenty-five gutta-percha cones were contaminated with standardized suspensions of each microorganism and incubated at 37°C for 24 h. The cones were divided into 10 experimental groups (n = 15, according to the microorganism tested and disinfection testing times. The disinfection procedure consisted of immersing each cone in a plastic tube containing the substance. The specimens remained in contact with the substance for 1 or 2.5 minutes. Afterwards, each cone was transferred to a 10% sodium thiosulphate solution (Na2S2O3 to neutralize the disinfectant. Microbial biofilms adhering to the cones were dispersed by agitation. Aliquots of 0.1 ml of the suspensions obtained were plated on Sabouraud dextrose agar, or brain and heart infusion agar, and incubated at 37°C for 24 h. The results were expressed in colony forming units (CFU/ml and the data were submitted to the Wilcoxon Signed Rank Test (level of significance at 0.05. A significant reduction was observed, after 1 minute of exposure, in the test solution for C. albicans (p = 0.0190, S. aureus (p = 0.0001, S. mutans (p = 0.0001, B. subtilis (p = 0.0001, and E. coli (p = 0.0001. After 2.5 minutes of exposure, 100% of the microbial inocula were eliminated. It was concluded that the 2% peracetic acid solution was effective against the biofilms of the tested microorganisms on gutta-percha cones at 1 minute of exposure.

Effectiveness of 2% peracetic acid for the disinfection of gutta-percha cones.

Science.gov (United States)

Salvia, Ana Carolina Rodrigues Danzi; Teodoro, Guilherme Rodrigues; Balducci, Ivan; Koga-Ito, Cristiane Yumi; Oliveira, Simone Helena Gonçalves de

2011-01-01

The aim of this study was to evaluate the effectiveness of 2% peracetic acid for the disinfection of gutta-percha cones contaminated in vitro with Escherichia coli, Staphylococcus aureus, Streptococcus mutans, Candida albicans and Bacillus subtilus (in spore form). Two hundred and twenty-five gutta-percha cones were contaminated with standardized suspensions of each microorganism and incubated at 37°C for 24 h. The cones were divided into 10 experimental groups (n = 15), according to the microorganism tested and disinfection testing times. The disinfection procedure consisted of immersing each cone in a plastic tube containing the substance. The specimens remained in contact with the substance for 1 or 2.5 minutes. Afterwards, each cone was transferred to a 10% sodium thiosulphate solution (Na(2)S(2)O(3)) to neutralize the disinfectant. Microbial biofilms adhering to the cones were dispersed by agitation. Aliquots of 0.1 ml of the suspensions obtained were plated on Sabouraud dextrose agar, or brain and heart infusion agar, and incubated at 37°C for 24 h. The results were expressed in colony forming units (CFU/ml) and the data were submitted to the Wilcoxon Signed Rank Test (level of significance at 0.05). A significant reduction was observed, after 1 minute of exposure, in the test solution for C. albicans (p = 0.0190), S. aureus (p = 0.0001), S. mutans (p = 0.0001), B. subtilis (p = 0.0001), and E. coli (p = 0.0001). After 2.5 minutes of exposure, 100% of the microbial inocula were eliminated. It was concluded that the 2% peracetic acid solution was effective against the biofilms of the tested microorganisms on gutta-percha cones at 1 minute of exposure.

EXPERIMENTAL COMPARISON OF THE AEROSOL METHOD OF DISINFECTION OF AIR AND SURFACES CONTAMINATED BY M. TUBERCULOSIS

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V. V. Kuzin

2018-01-01

Full Text Available The objective of the study: to analyze efficiency of an aerosol method of M. tuberculosis deactivation in the air and on surfaces versus the conventional methods of the disinfectants' application.Subjects and Methods. The article describes the evaluation of efficiency of the aerosol method of M. tuberculosis, H37Rv strain, deactivation on surfaces (tested objects made of linoleum and in the air using the disinfectant of Green Dez based on chlorine dioxide versus deactivation through wiping and irrigation.The efficiency of disinfectant was tested by the device of 099С А4224 manufactured by Glas-Col, USA, using the air sampler of PU-1B, Russia.The Mobile Hygienic Center (MNC, Russia, was used for application of the disinfectant, wiping and irrigation was done using the disperser of Avtomaks AO-2, Russia.The bacterial aerosol was generated in the Glass-Col chamber with the concentration 5 ± 2.5 × 102 CFU/cm3, by spraying the suspension of M. tuberculosis, H37Rv strain. After that, the disinfectant spray was supplied to the chamber, where linoleum objects were placed horizontally on a variety of surfaces. In order to evaluate efficiency of surface treatment by wiping, the test objects were wiped with a tissue, soaked with the solution of Green Dez, based on consumption of 100-150 ml/m2. In 15, 30 and 60 minutes, the samples of inactivated M. tuberculosis aerosol were collected using an aspirator, chambers with test objects were closed and placed in the vent hood. To monitor efficiency of disinfection of the test object surfaces, the rinse blanks were done by wiping the surface with a sterile gauze wad, soaked with 0.5% of sodium thiosulfate solution.The samples of deactivated aerosol and rinse blanks from the surfaces of test objects were put into Petri dishes with Middlebrook 7H11 medium. The cultures were incubated in the thermostat at the temperature of 37 ± 1° C for 10-21 days, and the number of colonies was counted.Sterile water was used

Is pomegranate peels infusion effective for disinfection of toothbrushes?

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Priscila Lima de Luna FREIRE

Full Text Available Abstract Introduction Methods of decontamination or sanitization of toothbrushes have been questioned. Objective This study assessed the effectiveness of pomegranate peels infusion as a disinfectant of toothbrushes against Streptococcus mutans. Material and method A sample of 16 schoolchildren aged between 7 and 9 years performed brushing 5 days/week, with a careful brushing once a day. After each day of brushing, the toothbrushes were washed and sprayed with one disinfectant solution. This procedure was repeated for 4 weeks using one of the different solutions per week: distilled water (G1; negative control, pomegranate (Punica granatum Linn peels infusion (G2, 1% sodium hypochlorite (G3 and 0.12% chlorhexidine digluconate (G4. After the fifth day, toothbrushes were collected for laboratory analysis. Toothbrushes heads were subjected to agitation in saline dilution of 10–1, 10–2,10–3, and 25 μL of each dilution were seeded in mitis salivarius agar culture medium for S. mutans colony-forming unit (CFU counting. One calibrated examiner (Kappa = 0.91 performed the CFU (mL–1 × 104 counts. Kruskal-Wallis and Dunn Multiple Comparison tests were used at a significance level of 5%. Result G1 presented the highest number of CFU (3.9 ± 8.4, followed by G2 (3.2 ± 4.0. No S. mutans growth was observed in G3 and G4. There was no statistically significant difference between G1 and G2 and between G3 and G4 (p>0.05. Conclusion Pomegranate infusion was completely ineffective for the disinfection of toothbrushes against S. mutans when compared with 1% sodium hypochlorite and 0.12% chlorhexidine digluconate solutions.

Wheelchair cleaning and disinfection in Canadian health care facilities: "That's wheelie gross!".

Science.gov (United States)

Gardner, Paula; Muller, Matthew P; Prior, Betty; So, Ken; Tooze, Jane; Eum, Linda; Kachur, Oksana

2014-11-01

Wheelchairs are complex equipment that come in close contact with individuals at increased risk of transmitting and acquiring antibiotic-resistant organisms and health care-associated infection. The purpose of this study was to determine the status of wheelchair cleaning and disinfection in Canadian health care facilities. Acute care hospitals (ACHs), chronic care hospitals (CCHs), and long-term care facilities (LTCFs) were contacted and the individual responsible for oversight of wheelchair cleaning and disinfection was identified. A structured interview was conducted that focused on current practices and concerns, barriers to effective wheelchair cleaning and disinfection, and potential solutions. Interviews were completed at 48 of the 54 facilities contacted (89%), including 18 ACHs, 16 CCHs, and 14 LTCFs. Most (n = 24) facilities had 50-200 in-house wheelchairs. Respondents were very concerned about wheelchair cleaning as an infection control issue. Specific concerns included the lack of reliable systems for tracking and identifying dirty and clean wheelchairs (71%, 34/48), failure to clean and disinfect wheelchairs between patients (52%, 25/48), difficulty cleaning cushions (42%, 20/48), lack of guidelines (35%, 27/48), continued use of visibly soiled wheelchairs (29%, 14/48) and lack of resources (25%, 12/48). Our results suggest that wheelchair cleaning and disinfection is not optimally performed at many Canadian hospitals and LTCFs. Specific guidance on wheelchair cleaning and disinfection is necessary. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Comparison of different techniques for disinfection of teeth internal space in preclinical teaching

Directory of Open Access Journals (Sweden)

Tabrizizadeh M.

2009-12-01

Full Text Available "nBackground and Aim: Extracted teeth used in preclinic should be disinfected. The aim of this study was to evaluate the effects of some disinfectants on microorganisms cultured from pulp chamber of extracted teeth."nMaterials and Methods: In this experimental study 54 intact human teeth were collected. After access cavity preparation, 10 8 B. streothermophillus endospors were inoculated into pulp chamber. Then cavities were sealed with a temporary restorative material. Teeth were divided into 5 groups of 10 each. The teeth were then stored in these disinfectants: 5.25% hypochlorite sodium, 5% Microten, 5% Deconex, 2% Glutaraldehyd, and 10% Formalin for 48 hours. Two teeth were autoclaved as negative controls and two were stored in normal saline as positive controls. The teeth were then sectioned in cervical area and cultured in Trypticase Soy Broth. After three days turbidity in tubes was evaluated. Statistical analysis was done by Fisher's exact test."nResults: None of these solutions were able to prevent microorganism growth in all samples; however, Formalin was better in six cases than that of other disinfectants. Differences between these five groups were not statistically significant (P=0.384."nConclusion: Sterilization of the teeth with autoclave is the only absolute method for disinfecting the root canals of extracted teeth and disinfectants are not reliable for this purpose.

Dynamics of cholera epidemics with impulsive vaccination and disinfection.

Science.gov (United States)

Sisodiya, Omprakash Singh; Misra, O P; Dhar, Joydip

2018-04-01

Waterborne diseases have a tremendous influence on human life. The contaminated drinking water causes water-borne disease like cholera. Pulse vaccination is an important and effective strategy for the elimination of infectious diseases. A waterborne disease like cholera can also be controlled by using impulse technique. In this paper, we have proposed a delayed SEIRB epidemic model with impulsive vaccination and disinfection. We have studied the pulse vaccination strategy and sanitation to control the cholera disease. The existence and stability of the disease-free and endemic periodic solution are investigated both analytically and numerically. It is shown that there exists an infection-free periodic solution, using the impulsive dynamical system defined by the stroboscopic map. It is observed that the infection-free periodic solution is globally attractive when the impulse period is less than some critical value. From the analysis of the model, we have obtained a sufficient condition for the permanence of the epidemic with pulse vaccination. The main highlight of this paper is to introduce impulse technique along with latent period into the SEIRB epidemic model to investigate the role of pulse vaccination and disinfection on the dynamics of the cholera epidemics. Copyright © 2018 Elsevier Inc. All rights reserved.

Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa biofilm

DEFF Research Database (Denmark)

Argyraki, Aikaterini; Markvart, M.; Nielsen, Anne

2016-01-01

skin, soft tissue, lungs, kidney and urinary tract infections. Moreover, it can be found on and in medical equipment causing often cross infections in hospitals. The objective of this study was to test the efficiency, of two different light-based disinfection treatments, namely UVB and UVC irradiation......, on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose......Disinfection routines are important in all clinical applications. The uprising problem of antibiotic resistance has driven major research efforts towards alternative disinfection approaches, involving light-based solutions. Pseudomonas aeruginosa (P. aeruginosa) is a common bacterium that can cause...

Spiral-shaped reactor for water disinfection

KAUST Repository

Soukane, Sofiane; Ait-Djoudi, Fariza; Naceur, Wahib M.; Ghaffour, NorEddine

2016-01-01

Chlorine-based processes are still widely used for water disinfection. The disinfection process for municipal water consumption is usually carried out in large tanks, specifically designed to verify several hydraulic and disinfection criteria

Irradiation as an alternative for disinfection of domestic waste in the Canadian Arctic

International Nuclear Information System (INIS)

1981-01-01

This study evaluated the technical and economic feasibility of various methods for disinfecting wastewater in the Canadian Arctic with specific reference to gamma radiation. More conventional disinfection practices, such as chlorination, chlorination-dechlorination, and ozonation were compared to gamma radiation along with ultraviolet irradiation and lime disinfection. The quality of lagoon effluent, highly diluted (weak) sewage, holding tank wastes and honey-bag wastes, which are the typical waste types found in northern communities, was established from data available in the literature. Further literature reviews were undertaken to establish a data base for design and effectiveness of disinfection systems operated in cold climates. Capital and operating costs for all technically feasible disinfection process alternates were estimated based on historical cost data adjusted to 1977 for the construction and instalation of similar systems in the north. The costs of equipment, chemicals, fuel and electrical power were obtained from suppliers. The environmental impact of each of the disinfection processes was reviewed with emphasis on gamma irradiation. Safety and health aspects were also considered. The study concluded that gamma irradiation was capable of providing safe, reliable disinfection for concentrated honey-bag and holding wastes. Pilot-scale testing was recommended prior to construction of full-scale disinfection facilities. For lagoon effluents and weak sewage, gamma irradiation was not cost competitive with other alternates; rather chlorination-dechlorination was found to be the most cost-effective and environmentally acceptable alternative

Evaluation of the Efficacy of Different Mixing Techniques and Disinfection on Microbial Colonization of Polyether Impression Materials: A Comparative Study.

Science.gov (United States)

Singla, Youginder; Pachar, Renu B; Poriya, Sangeeta; Mishra, Aalok; Sharma, Rajni; Garg, Anshu

2018-03-01

This study aims to determine the role of mixing techniques of polyether impression materials and efficacy of disinfection on microbial colonization of these impression materials. Polyether impression material was mixed using two methods: First by hand mixing (group I) and second using an automixer (group II) with a total of 100 samples. Four microbial strains were studied, which included Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. After incubation, the bacterial colonies were counted, and then, disinfectant solution was applied. The effect of disinfection solution was evaluated for each specimen. The surface of polyether impression materials mixed with an automixer has less number of voids and overall a smoother surface as compared with the hand-mixed ones. On comparing the disinfection procedures, i.e., specimens without any disinfection and specimens after disinfection, statistically highly significant difference was seen between all the groups. We can conclude that impression mixing procedures are important in determining the surface characteristics of the impression and ultimately the colonization of bacteria and also determine the importance of disinfection on microbial colonization. This study emphasises the deleterious role of nosocomial infections and specific measures that should be taken regarding the prevention of such diseases. Dental impressions are proved to be a source of such infections and may lead to transmission of such diseases. Thus, proper measures should be taken right from the first step of impression taking to minimizing and preventing such kind of contaminations in clinical practice.

Sensitivity to disinfection of bacterial indicator organisms for monitoring the Salmonella Enteritidis status of layer farms after cleaning and disinfection.

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Dewaele, I; Ducatelle, R; Herman, L; Heyndrickx, M; De Reu, K

2011-06-01

The present study evaluated Escherichia coli, Enterococcus faecalis, and Enterococcus hirae as potential indicator organisms for the possible Salmonella Enteritidis (SE) presence in layer farms after cleaning and disinfection by comparing their susceptibility to disinfection. A quantitative suspension disinfection test according to European Standard EN1656 was performed using disinfection products CID20 and Virocid (both from CID Lines, Ieper, Belgium). In a preliminary test, the sensitivity to both disinfection products was compared between ATCC strains of SE, E. coli, En. faecalis, and En. hirae. The sensitivity of SE to disinfection was most comparable to that of E. coli. A second disinfection test compared the elimination of E. coli to SE ATCC strains as well as field strains. Results showed no significant effect regarding the strain (P > 0.05 for CID20 and Virocid), meaning that no difference was detected in sensitivity toward disinfection. When comparing the sensitivity in general at species level for all concentrations of disinfectant used, no significant difference was found between E. coli and SE in sensitivity to Virocid (P > 0.05). In conclusion, because of its similar response to disinfection in a suspension disinfection test, E. coli could be used as an indicator for possible Salmonella presence after cleaning and disinfection.

Microbiological Efficacy Test Methods of Disinfectants

OpenAIRE

Şahiner, Aslı

2015-01-01

Disinfection process is required in every area where microbiological contamination and infection risk is present, especially in medical sector, food, veterinary and general common living areas hence many disinfectants and antiseptics are being produced for different purposes. Disinfectants are made up a large group of biocidal products. Depending on the chemical properties of active substances, targeted microorganisms may differ While some disinfectants are effective in a large spectrum, othe...

DISINFECTION BY-PRODUCT FORMATION BY ALTERNATIVE DISINFECTANTS AND REMOVAL BY GRANULAR ACTIVATED CARBON

Science.gov (United States)

The effects of the use of the alternative disinfectants on the formation of halogenated disinfection by–products (DBPs) including total organic halide, trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, chloral hydrate, and chloropicrin, were examined along ...

Efficacy of peracetic acid in rapid disinfection of Resilon and gutta-percha cones compared with sodium hypochlorite, chlorhexidine, and povidone-iodine.

Science.gov (United States)

Subha, N; Prabhakar, V; Koshy, Minu; Abinaya, K; Prabu, M; Thangavelu, Lavanya

2013-10-01

The aim of this investigation was to compare the effectiveness of 3% sodium hypochlorite (NaOCl), 2% chlorhexidine, 1% peracetic acid, and 10% povidone-iodine in the rapid disinfection of Resilon (Pentron Clinical Technologies, LLC, Wallingford, CT) and gutta-percha cones contaminated with Enterococcus faecalis and Bacillus subtilis. Two hundred fifty-six samples consisting of 128 gutta-percha cones and 128 Resilon cones were used in this study. The materials were tested for disinfection according to the type of solution (3% NaOCl, 2% chlorhexidine, 1% peracetic acid, or 10% povidone-iodine), the time of exposure to each solution (1 or 5 minutes), and the type of microorganisms (E. faecalis or B. subtilis). Subsequent to the disinfection, samples were placed in test tubes containing 10 mL Mueller-Hinton broth and incubated at 37°C for 7 days. All test tubes were observed at 24-hour intervals and visually checked for turbidity, signifying microbial growth. In this study, 1% peracetic acid showed the best results for both 1 minute and 5 minutes of disinfection, 2% chlorhexidine showed the second best results although it was statistically at par with peracetic acid, and 3% hypochlorite ranked third in disinfection; this was statistically significant when compared with peracetic acid and chlorhexidine. Disinfection by povidone-iodine was the least within all the groups for both contact times although disinfection for 5 minutes showed better results than disinfection for 1 minute for gutta-percha. The outcome of this study confirmed the efficacy of 1% peracetic acid and 2% chlorhexidine in the rapid disinfection of both Resilon and gutta-percha. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Chlorine dioxide as a disinfectant for Ralstonia solanacearum control in water, storage and equipment

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Popović Tatjana

2016-01-01

Full Text Available Brown rot or bacterial wilt caused by bacterium Ralstonia solanacearum is the main limiting factor in potato production. Quarantine measures are necessary to avoid spread of disease to disease-free areas. R. solanacearum has been shown to contaminate watercourses from which crop irrigation is then prohibited causing further potential losses in yield and quality. The bacteria also spread via surfaces that diseased seed potatoes come into contact with. This study showed bactericidal activity of chlorine dioxide (CIO2 on R. solanacearum for disinfection of water, surface and equipment. The results showed that CIO2 solution at concentration of 2 ppm at 30 minutes of exposure time had bactericidal effect for disinfection of water. For surface and equipment disinfection, concentration of 50 ppm showed total efficacy at 30 min and 5 sec exposure time, respectively. Results suggest that use of CIO2 as a disinfectant has a potential for control of brown rot pathogen in water, storage and equipment.

Ultraviolet disinfection of treated municipal wastewaters

Energy Technology Data Exchange (ETDEWEB)

Vander Laan, H; Cairns, B

1993-12-31

A wastewater disinfection system developed by a Canadian company, Trojan Technologies Inc., was discussed. Disinfection for pathogen reduction prior to discharge of treated municipal wastewater back into rivers and lakes has been either ignored or treated by the use of chemicals. In 1979 the first pilot ultraviolet (UV) wastewater disinfection system was established. Since then, over 500 municipal UV installations have been commissioned. The largest installation can process 212 million gallons of water per day. The advantages of UV as a disinfectant are: (1) It is more effective than chlorine. (2) There are no mutagenic/carcinogenic byproducts formed with UV. (3) No toxic chemical residuals are discharged. (4) UV is safe to both the operators and the public. (5) It is cost effective. Europe has not been as active in wastewater disinfection as has North America. One result of the absence of wastewater disinfection in Europe is that the Rhine River, for example, carries 50 million salmonella per second. Disinfection of wastewater effluents is, of course, indispensable in protecting our drinking water supply. 2 figs.

Disinfection of human musculoskeletal allografts in tissue banking: a systematic review.

Science.gov (United States)

Mohr, J; Germain, M; Winters, M; Fraser, S; Duong, A; Garibaldi, A; Simunovic, N; Alsop, D; Dao, D; Bessemer, R; Ayeni, O R

2016-12-01

Musculoskeletal allografts are typically disinfected using antibiotics, irradiation or chemical methods but protocols vary significantly between tissue banks. It is likely that different disinfection protocols will not have the same level of microorganism kill; they may also have varying effects on the structural integrity of the tissue, which could lead to significant differences in terms of clinical outcome in recipients. Ideally, a disinfection protocol should achieve the greatest bioburden reduction with the lowest possible impact on tissue integrity. A systematic review of three databases found 68 laboratory and clinical studies that analyzed the microbial bioburden or contamination rates of musculoskeletal allografts. The use of peracetic acid-ethanol or ionizing radiation was found to be most effective for disinfection of tissues. The use of irradiation is the most frequently published method for the terminal sterilization of musculoskeletal allografts; it is widely used and its efficacy is well documented in the literature. However, effective disinfection results were still observed using the BioCleanse™ Tissue Sterilization process, pulsatile lavage with antibiotics, ethylene oxide, and chlorhexidine. The variety of effective methods to reduce contamination rate or bioburden, in conjunction with limited high quality evidence provides little support for the recommendation of a single bioburden reduction method.

Photoreactivation Study of Wastewater Treatment Effluent Disinfected by UV-disinfection for Water Reuse

International Nuclear Information System (INIS)

Yoon, C.G.; Jung, K.W.; Ham, J.H.; Jeon, J.H.

2003-01-01

Photoreactivation of microorganism following UV-disinfection is one of the research topics of interest in assessing the UV-disinfection performance. Apparent photoreactivation was examined under fluorescent lamp and solar radiation as well as in darkness. Total coliform, fecal coliform, and Escherichia coli were used as indicator microorganisms, and their concentration of 10~30 MPN/100mL increased to the level of 100 MPN/100mL after 24 hours, which implied that part of damaged microorganisms by UV-disinfection might be repairable with time

Biological Treatment of Water Disinfection Byproducts using ...

Science.gov (United States)

Major disinfection by-products (DBPs) from the chlorination process of drinking water include trihalomethanes (THMs) and haloacetic acides (HAA5). THMs mainly consist of chloroform, and other harsh chemicals. Prolonged consumptions of drinking water containing high levels of THMs has been linked with diseases of the liver, kidneys, bladder, or central nervous system and may increase likelihood of cancer. A risk also exists for THMs exposure via inhalation while showering, bathing or washing clothes and dishes. Due to these risks, the U.S. EPA regulate THMs content in drinking water. This research investigates biological degradation of THM using chloroform as a model compound. The study aims to decrease possible risks of THMs through filtration. Throughout this year’s presentations, there is a common theme of health and safety concerns. UC researchers are working hard to clean water ways of naturally occurring contaminates as well as man-made toxins found in our waterways. The significance of these presentations translates into the promise of safer environments, and more importantly saved lives, as UC’s faculty continues to produce real-world solutions to problems threatening the world around us. A biotech process has been developed and demonstrated that effectively remove and treat volatile disinfection by-products from drinking water. The process strips low concentration disinfection by-products, such as trihalomethanes, that are formed during the chlori

A Modern Approach to Disinfection, as Old as the Evolution of Vertebrates

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Franco Migliarina

2014-12-01

Full Text Available The immune system of vertebrates “naturally” produces hypochlorous acid (HOCl to fight against bacteria and pathogens. A patented electrochemical technology mirrors the above defense system, allowing the synthesis of HOCl solutions through the electrolysis of water enriched in salts, at the level of a few grams per liter. The system allows for the careful control of the pH of produced solutions, with consequent optimization of their activity. Once the HOCl is introduced into the water system; it is able to remove the biofilm from pipe network; significantly decreasing the level of Legionella colonization; within 8–10 weeks from the beginning of the disinfection approach. The technology has been applied in a variety of healthcare facilities, both in Italy and in neighboring European countries. In the present paper, two successful case studies are briefly presented: Data were obtained from experiences in two different healthcare facilities, one in Italy and the other in Germany. Destruction of biofilm was indirectly testified by an increase of total organic carbon content of water; as a consequence, and because of the dosing of the disinfecting agent, some μg/L of total halomethanes were also formed. However, both compositional features were only observed during the initial stages of the disinfection treatment.

Efficacy of Various Chemical Disinfectants on Biofilms Formed in Spacecraft Potable Water System Component

Science.gov (United States)

Wong, Willy; Garcia, Veronica; Castro, Victoria; Ott, Mark; Duane

2009-01-01

As the provision of potable water is critical for successful habitation of the International Space Station (ISS), life support systems were installed in December 2008 to recycle both humidity from the atmosphere and urine to conserve available water in the vehicle. Pre-consumption testing from the dispensing needle at the Potable Water Dispenser (PWD) indicated that bacterial concentrations exceeded the current ISS specifications of 50 colony forming units (CFU) per ml. Subsequent investigations revealed that a corrugated stainless steel flex hose upstream of the dispensing needle in the PWD was filled with non-sterile water and left at room temperature for over one month before launch. To simulate biofilm formation that was suspected in the flight system, sterile flex hoses were seeded with a consortium of bacterial isolates previously recovered from other ISS water systems, which included Ralstonia pickettii, Burkholderia multivorans, Caulobacter vibrioides., and Cupriavidus pauculus. After 5 days of incubation, these hoses were challenged with various chemical disinfectants including hydrogen peroxide, colloidal silver, and buffered pH solutions to determine the ability of the disinfectants to decrease and maintain bacterial concentrations below ISS specifications. Disinfection efficacy over time was measured by collecting daily heterotrophic plate counts following exposure to the disinfectants. A single flush with either 6% hydrogen peroxide solution or a mixture of 3% hydrogen peroxide and 400 ppb colloidal silver effectively reduced the bacterial concentrations to less than 1 CFU/ml for a period of up to 2 months. Testing results indicated that hydrogen peroxide and mixtures of hydrogen peroxide and colloidal silver have tremendous potential as alternative disinfectants for ISS water systems.

[On the bactericidal action of dibromoisocyanuric acid; experiments concerning the disinfection of hands (author's transl)].

Science.gov (United States)

Gottardi, W; Puritscher, M

1976-07-01

The action of dibromoisocyanuric acid (DBI), C12, Br2, trichloroisocyanuric acid (TCI) and chloramine T against Staph. aureus SG 511 was compared. Using the suspension test DBI and Br2 showed the strongest, chloramine T however, the weakest bactericidal power (Tab 2). Under the conditions of the "Hygienic disinfection of hands" a 0.005 M solution of DBI met the requirements specified in the "Richtlinien für die Prüfung chemischer Desinfektionsmittel" (3. Ed., Stuttgart: Gustav Fischer Verlag, 1972), and was comparable to a chloramine T solution containing the same amount of active halogen (Tab. 3). The decrease of disinfection power compared with the suspension test can be attributed to a great error induced by protein.

9 CFR 166.14 - Cleaning and disinfecting.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfecting. 166.14... AGRICULTURE SWINE HEALTH PROTECTION SWINE HEALTH PROTECTION General Provisions § 166.14 Cleaning and disinfecting. (a) Disinfectants to be used. Disinfection required under the regulations in this Part shall be...

Comparison of the role of attachment, aggregation and internalisation of microorganisms in UVC and UVA (solar) disinfection.

Science.gov (United States)

Bichai, Françoise; Léveillé, Simon; Barbeau, Benoit

2011-01-01

In this comparative study, the impact of two microbial protective mechanisms against simulated UVA disinfection was assessed by using protocols previously developed for UVC disinfection assays. (i) The impact of natural microorganism aggregation and attachment to particles was assessed by targeting total coliform bacteria in natural surface water samples. (ii) The impact of bacteria internalisation by zooplankton was assessed by using C. elegans nematodes as a model host and E. coli as a bacterial target for UVA inactivation. Dispersion of natural aggregates by blending prior to UVA exposure was shown to enhance the inactivation rate of total coliforms as compared to untreated raw water. Removal of particles by an 8-microm membrane filtration did not improve UVA disinfection efficiency. Twenty-four per cent of the highest applied UVA fluence was found to reach internalised E. coli in nematodes. Both aggregation and internalisation showed similar impact as protective mechanisms against UVA and UVC bacterial inactivation.

UV disinfection in drinking water supplies.

Science.gov (United States)

Hoyer, O

2000-01-01

UV disinfection has become a practical and safely validatable disinfection procedure by specifying the requirements for testing and monitoring in DVGW standard W 294. A standardized biodosimetric testing procedure and monitoring with standardized UV sensors is introduced and successfully applied. On-line monitoring of irradiance can be counterchecked with handheld reference sensors and makes it possible that UV systems can be used for drinking water disinfection with the same level of confidence and safety as is conventional chemical disinfection.

Effect of immersion disinfection of alginate impressions in sodium hypochlorite solution on the dimensional changes of stone models.

Science.gov (United States)

Hiraguchi, Hisako; Kaketani, Masahiro; Hirose, Hideharu; Yoneyama, Takayuki

2012-01-01

This study investigated the effect of the immersion of alginate impressions in 0.5% sodium hypochlorite solution for 15 min on the dimensional changes of stone models designed to simulate a sectional form of a residual ridge. Five brands of alginate impression materials, which underwent various dimensional changes in water, were used. A stone model made with an impression that had not been immersed was prepared as a control. The immersion of two brands of alginate impressions that underwent small dimensional changes in water did not lead to serious deformation of the stone models, and the differences in the dimensional changes between the stone models produced with disinfected impressions and those of the control were less than 15 µm. In contrast, the immersions of three brands of alginate impressions that underwent comparatively large dimensional changes in water caused deformation of the stone models.

Antimicrobial activity of disinfectant agents incorporated into type IV dental stone.

Science.gov (United States)

Pereira, Rodrigo de Paula; Lucas, Matheus Guilherme; Spolidorio, Denise Madalena Palomari; Arioli Filho, João Neudenir

2012-06-01

This study evaluated the antimicrobial activity of two disinfectant agents, 2% chlorhexidine digluconate solution (CHX) and 98% chlorhexidine hydrochloride powder (HYD), incorporated into type IV dental stone at the time of mixing. Agar diffusion test was used for the following microorganisms: Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Candida albicans. The specimens were grouped in: (1) dental stone mixed with sterile distilled water; (2) paper disc soaked with CHX; (3) dental stone mixed with CHX; and (4) dental stone with incorporation of HYD, in 1% proportion of the dental stone mass and mixed with sterile distilled water. The culture medium was inoculated with microbial suspensions 1 and 24 h after pouring of the dental stone. The antimicrobial activity was evaluated by the average diameter of microbial growth inhibition zones. The data were analysed with a nested anova (p < 0.05) and Tukey test for specific comparisons. The disinfectant agents demonstrated antimicrobial activity against all microorganisms, with the exception of C. albicans, against which the CHX was ineffective in two periods of analysis. Significant differences between disinfectants were found with all microorganisms. The disinfectant agents analysed were effective against most of the microorganisms tested, except C. albicans. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

Elimination of biofilm and microbial contamination reservoirs in hospital washbasin U-bends by automated cleaning and disinfection with electrochemically activated solutions.

Science.gov (United States)

Swan, J S; Deasy, E C; Boyle, M A; Russell, R J; O'Donnell, M J; Coleman, D C

2016-10-01

Washbasin U-bends are reservoirs of microbial contamination in healthcare environments. U-Bends are constantly full of water and harbour microbial biofilm. To develop an effective automated cleaning and disinfection system for U-bends using two solutions generated by electrochemical activation of brine including the disinfectant anolyte (predominantly hypochlorous acid) and catholyte (predominantly sodium hydroxide) with detergent properties. Initially three washbasin U-bends were manually filled with catholyte followed by anolyte for 5min each once weekly for five weeks. A programmable system was then developed with one washbasin that automated this process. This U-bend had three cycles of 5min catholyte followed by 5min anolyte treatment per week for three months. Quantitative bacterial counts from treated and control U-bends were determined on blood agar (CBA), R2A, PAS, and PA agars following automated treatment and on CBA and R2A following manual treatment. The average bacterial density from untreated U-bends throughout the study was >1×10(5) cfu/swab on all media with Pseudomonas aeruginosa accounting for ∼50% of counts. Manual U-bend electrochemically activated (ECA) solution treatment reduced counts significantly (<100cfu/swab) (P<0.01 for CBA; P<0.005 for R2A). Similarly, counts from the automated ECA-treatment U-bend were significantly reduced with average counts for 35 cycles on CBA, R2A, PAS, and PA of 2.1±4.5 (P<0.0001), 13.1±30.1 (P<0.05), 0.7±2.8 (P<0.001), and 0 (P<0.05) cfu/swab, respectively. P. aeruginosa was eliminated from all treated U-bends. Automated ECA treatment of washbasin U-bends consistently minimizes microbial contamination. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Microwave discharge electrodeless lamps (MDEL). V. Microwave-assisted photolytic disinfection of Bacillus subtilis in simulated electroplating wash wastewaters.

Science.gov (United States)

Horikoshi, Satoshi; Tsuchida, Akihiro; Abe, Masahiko; Ohba, Naoki; Uchida, Masayoshi; Serpone, Nick

2010-01-01

This short article examines the microwave-assisted photolytic disinfection of aqueous solutions contaminated by Bacillus subtilis microorganisms using UV and vacuum-UV radiation emitted from a microwave discharge electrodeless lamp (MDEL), a device containing a Hg/Ar gas-fill that was proposed recently for use in Advanced Oxidation Processes (AOPs). Results of the disinfection are compared with those obtained from UV radiation emitted by a low-pressure electrode Hg lamp and by an excimer lamp. Also examined is the disinfection of B. subtilis aqueous media that contained Au3+ or Ni2+ ions, species often found in the treatment of electroplating wash wastewaters.

Humidifier disinfectants, unfinished stories

Directory of Open Access Journals (Sweden)

Yeyong Choi

2016-02-01

Full Text Available Once released into the air, humidifier disinfectants became tiny nano-size particles, and resulted in chemical bronchoalveolitis. Families had lost their most beloved members, and even some of them became broken. Based on an estimate of two million potential victims who had experienced adverse effects from the use of humidifier disinfectants, we can say that what we have observed was only the tip of the iceberg. Problems of entire airways, as well as other systemic effects, should be examined, as we know these nano-size particles can irritate cell membranes and migrate into systemic circulation. The story of humidifier disinfectant is not finished yet.

Environmental cleaning and disinfection.

Science.gov (United States)

Traverse, Michelle; Aceto, Helen

2015-03-01

The guidelines in this article provide veterinarians, veterinary technicians, and veterinary health care workers with an overview of evidence-based recommendations for the best practices associated with environmental cleaning and disinfection of a veterinary clinic that deals with small animals. Hospital-associated infections and the control and prevention programs necessary to alleviate them are addressed from an environmental perspective. Measures of hospital cleaning and disinfection include understanding mechanisms and types of contamination in veterinary settings, recognizing areas of potential concern, addressing appropriate decontamination techniques and selection of disinfectants, the management of potentially contaminated equipment, laundry, and waste management, and environmental surveillance strategies. Copyright © 2015 Elsevier Inc. All rights reserved.

Study and application of herbal disinfectants in China.

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Chen, Zhao-Bin

2004-12-01

Disinfection means killing or removing pathogenic microorganisms in media to realize a harmless process. A disinfectant, which is also referred to as a disinfection medicine in relevant regulations, is the medicine used to kill microorganisms for the purpose of disinfection. The disinfectants prepared from plants (including traditional Chinese herbal medicines) and the extracts thereof are called herbal disinfectants. China has a long history of using herbal disinfectants. As early as in 533 A.D., the use of Cornel to sterilize well water was recorded in Necessary Techniques for Qi People by Jia Enxie of the Beiwei Dynasty. During the Dragon Boat Festival, people often use fumigants made of traditional Chinese herbal medicines like Chinese Atractylodes, Argy Wormwood Leaf and Red Arsenic Sulfide to smoke their houses, so as to ward off plagues and drive away evils. In fact this is now a kind of disinfection practice.

Ultraviolet light-emitting diodes in water disinfection.

Science.gov (United States)

Vilhunen, Sari; Särkkä, Heikki; Sillanpää, Mika

2009-06-01

The novel system of ultraviolet light-emitting diodes (UV LEDs) was studied in water disinfection. Conventional UV lamps, like mercury vapor lamp, consume much energy and are considered to be problem waste after use. UV LEDs are energy efficient and free of toxicants. This study showed the suitability of LEDs in disinfection and provided information of the effect of two emitted wavelengths and different test mediums to Escherichia coli destruction. Common laboratory strain of E. coli (K12) was used and the effects of two emitted wavelengths (269 and 276 nm) were investigated with two photolytic batch reactors both including ten LEDs. The effects of test medium were examined with ultrapure water, nutrient and water, and nutrient and water with humic acids. Efficiency of reactors was almost the same even though the one emitting higher wavelength had doubled optical power compared to the other. Therefore, the effect of wavelength was evident and the radiation emitted at 269 nm was more powerful. Also, the impact of background was studied and noticed to have only slight deteriorating effect. In the 5-min experiment, the bacterial reduction of three to four log colony-forming units (CFU) per cubic centimeter was achieved, in all cases. When turbidity of the test medium was greater, part of the UV radiation was spent on the absorption and reactions with extra substances on liquid. Humic acids can also coat the bacteria reducing the sensitivity of the cells to UV light. The lower wavelength was distinctly more efficient when the optical power is considered, even though the difference of wavelengths was small. The reason presumably is the greater absorption of DNA causing more efficient bacterial breakage. UV LEDs were efficient in E. coli destruction, even if LEDs were considered to have rather low optical power. The effect of wavelengths was noticeable but the test medium did not have much impact. This study found UV LEDs to be an optimal method for bacterial

Predictors of stethoscope disinfection among pediatric health care providers.

Science.gov (United States)

Muniz, Jeanette; Sethi, Rosh K V; Zaghi, Justin; Ziniel, Sonja I; Sandora, Thomas J

2012-12-01

Stethoscopes are contaminated with bacteria, but predictors of stethoscope disinfection frequency are unknown. We sought to describe health care provider stethoscope disinfection attitudes and practices and determine predictors of frequent disinfection. We used an anonymous online survey of nurses, nurse practitioners, and physicians at a pediatric hospital. We assessed frequency and methods of disinfection, perceptions of contamination, and barriers to disinfection. Multivariate logistic regression models were used to identify independent predictors of disinfecting after every use. One thousand four hundred one respondents completed the survey: 76% believed that infection transmission occurs via stethoscopes, but only 24% reported disinfecting after every use. In multivariate analyses, belief that infection transmission occurs via stethoscopes significantly increased the odds of disinfection after every use (odds ratio [OR], 2.06 [95% confidence interval (CI): 1.38-3.06]). The odds of disinfection after every use were significantly decreased in those who perceived the following barriers: lack of time (OR, 0.31 [95% CI: 0.18-0.54]), lack of access to disinfection material (OR, 0.41 [95% CI: 0.29-0.57]), or lack of visual reminders to disinfect (OR, 0.22 [95% CI: 0.14-0.34]). Only a minority of pediatric health care providers reported disinfecting their stethoscopes after every use. Increasing access to disinfection materials and visual reminders in health care facilities may improve stethoscope disinfection practices. Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Disinfectant activity against different morphological forms of Helicobacter pylori: first results

Czech Academy of Sciences Publication Activity Database

Gebel, J.; Vacata, V.; Sigler, Karel; Pietsch, H.; Rechenburg, A.; Exner, M.; Kistemann, T.

2001-01-01

Roč. 48, Suppl A (2001), s. 58-63 ISSN 0195-6701 Institutional research plan: CEZ:AV0Z5020903 Keywords : desinfection * disinfectant efficacy * Helicobacter pylori Subject RIV: EE - Microbiology, Virology Impact factor: 1.983, year: 2001

Emergency Disinfection of Drinking Water

Science.gov (United States)

How to boil and disinfect water to kill most disease-causing microorganisms during emergency situations where regular water service has been interrupted and local authorities recommend using only bottled water, boiled water, or disinfected water.

Phytochemical profiling as a solution to palliate disinfectant limitations.

Science.gov (United States)

Malheiro, J; Gomes, I; Borges, A; Bastos, M M S M; Maillard, J-Y; Borges, F; Simões, M

2016-10-01

The indiscriminate use of biocides for general disinfection has contributed to the increased incidence of antimicrobial tolerant microorganisms. This study aims to assess the potential of seven phytochemicals (tyrosol, caffeic acid, ferulic acid, cinnamaldehyde, coumaric acid, cinnamic acid and eugenol) in the control of planktonic and sessile cells of Staphylococcus aureus and Escherichia coli. Cinnamaldehyde and eugenol showed antimicrobial properties, minimum inhibitory concentrations of 3-5 and 5-12 mM and minimum bactericidal concentrations of 10-12 and 10-14 mM against S. aureus and E. coli, respectively. Cinnamic acid was able to completely control adhered bacteria with effects comparable to peracetic acid and sodium hypochlorite and it was more effective than hydrogen peroxide (all at 10 mM). This phytochemical caused significant changes in bacterial membrane hydrophilicity. The observed effectiveness of phytochemicals makes them interesting alternatives and/or complementary products to commonly used biocidal products. Cinnamic acid is of particular interest for the control of sessile cells.

Evaluation of calcium hydrogen carbonate mesoscopic crystals as a disinfectant for influenza A viruses

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NAKASHIMA, Ryuji; KAWAMOTO, Masaomi; MIYAZAKI, Shigeru; ONISHI, Rumiko; FURUSAKI, Koichi; OSAKI, Maho; KIRISAWA, Rikio; SAKUDO, Akikazu; ONODERA, Takashi

2017-01-01

In this study, the virucidal effect of a novel electrically charged disinfectant CAC-717 was investigated. CAC-717 is produced by applying an electric field to mineral water containing calcium hydrogen carbonate to generate mesoscopic crystals. Virus titration analysis showed a >3 log reduction of influenza A viruses after treatment with CAC-717 for 1 min in room temperature, while infectivity was undetectable after 15 min treatment. Adding bovine serum albumin to CAC-717 solution did not affect the disinfectant effect. Although CAC-717 is an alkaline solution (pH=12.39), upon contact with human tissue, its pH becomes almost physiological (pH 8.84) after accelerated electric discharge, which enables its use against influenza viruses. Therefore, CAC-717 may be used as a preventative measure against influenza A viruses and for biosecurity in the environment. PMID:28392537

Efficacy of various chemical disinfectants on biofilms formed in spacecraft potable water system components.

Science.gov (United States)

Wong, Wing C; Dudinsky, Lynn A; Garcia, Veronica M; Ott, Charlie M; Castro, Victoria A

2010-07-01

As the provision of potable water is critical for successful habitation of the International Space Station (ISS), life support systems were installed in December 2008 to recycle both humidity from the atmosphere and urine to conserve available water in the Station. In-flight pre-consumption testing from the dispensing needle at the Potable Water Dispenser (PWD) indicated that bacterial concentrations exceeded the current ISS specifications of 50 colony-forming units (CFU) ml(-1). Subsequent investigations revealed that a corrugated stainless steel flex hose upstream of the dispensing needle in the PWD was filled with nonsterile water and left at room temperature for more than 1 month before launch. To simulate biofilm formation that was suspected in the flight system, sterile flex hoses were seeded with a consortium of bacterial isolates previously recovered from other ISS water systems, including Ralstonia pickettii, Burkholderia multivorans, Caulobacter vibrioides, and Cupriavidus pauculus. After incubation for 5 days, the hoses were challenged with various chemical disinfectants including hydrogen peroxide (H2O2), colloidal silver, and buffered pH solutions to determine the ability of the disinfectants to decrease and maintain bacterial concentrations below ISS specifications. The disinfection efficacy over time was measured by collecting daily heterotrophic plate counts after exposure to the disinfectants. A single flush with either 6% H2O2 solution or a mixture of 3% H2O2 and 400 ppb colloidal silver effectively reduced the bacterial concentrations to <1 CFU ml(-1) for a period of up to 3 months.

Corneal epithelial alterations resulting from use of chlorine-disinfected contact tonometer after myopic photorefractive keratectomy.

Science.gov (United States)

Maldonado, M J

1998-08-01

This study aimed to describe a previously unreported complication associated with the use of chlorine-disinfected applanation tonometer heads for intraocular pressure measurement after excimer laser photorefractive keratectomy. Two retrospective case reports. Two patients underwent, respectively, a 7-diopter and a 4-diopter myopic excimer laser correction in their first eye 2 weeks apart. Complete epithelial closure of the ablated area was observed by biomicroscopy in the first-week examination. Four weeks after photorefractive keratectomy, a complete ophthalmic examination was performed. Goldmann applanation tonometry was performed bilaterally after thoroughly rinsing and drying the tonometer biprism, which had been immersed regularly in a chlorine 5000-parts per million solution. Slit-lamp examination and corneal topographic surface regularity were measured. A few minutes after applanation tonometry, both patients reported ocular discomfort in the excimer laser-treated eyes, whereas the untreated fellow eyes were painless. Punctate corneal lesions and superficial epithelial cell clumping were present in the first patient's treated eye, predominantly in the inferior aspect of the applanated cornea. Visual inspection showed a normal tonometer tip. In the second patient's treated cornea, a focal epithelial defect was identified biomicroscopically, which corresponded to the steeper region within the ablation zone on the videokeratograph. In this case, crystal deposits were found on the tonometer tip. The epithelial alterations resolved without sequelae in both cases. Disinfecting solutions of chlorine can cause crystal deposit formation on the tonometer head. Applanation tonometry after repeated disinfection with chlorine solutions appears to have the potential for disrupting the epithelial layer of the healing cornea. Covered contact tonometry or noncontact tonometry should be evaluated as alternative methods to chemically disinfected contact tonometry for

Zinc oxide nanoparticles for water disinfection

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Emelita Asuncion S. Dimapilis

2018-03-01

Full Text Available The world faces a growing challenge for adequate clean water due to threats coming from increasing demand and decreasing supply. Although there are existing technologies for water disinfection, their limitations, particularly the formation of disinfection-by-products, have led to researches on alternative methods. Zinc oxide, an essential chemical in the rubber and pharmaceutical industries, has attracted interest as antimicrobial agent. In nanoscale, zinc oxide has shown antimicrobial properties which make its potential great for various applications. This review discusses the synthesis of zinc oxide with focus on precipitation method, its antimicrobial property and the factors affecting it, disinfection mechanisms, and the potential application to water disinfection.

Influence of disinfection with peracetic acid and hypochlorite in dimensional alterations of casts obtained from addition silicone and polyether impressions.

Science.gov (United States)

Queiroz, Daher Antonio; Peçanha, Marcelo Massaroni; Neves, Ana Christina Claro; Frizzera, Fausto; Tonetto, Mateus Rodrigues; Silva-Concílio, Laís Regiane

2013-11-01

Dental impressions disinfection is important to reduce the risk of cross contamination but this process may produce dimensional distortions. Peracetic acid is a disinfectant agent with several favorable characteristics yet underutilized in Dentistry. The aim of this paper is to compare the dimensional stability of casts obtained from addition silicone and polyether impressions that were immersed for 10 minutes in a solution of 0.2% peracetic acid or 1% sodium hypochlorite. Sixty samples in type IV gypsum were produced after a master cast that simulated a full crown preparation of a maxillary premolar. Samples were divided in 6 groups (n = 10) according to the impression material and disinfection agent: Group AC--addition silicone control (without disinfectant); Group APA--addition silicone + 0.2% peracetic acid; Group AH--addition silicone + 1% sodium hypochlorite; Group PC--polyether control (without disinfectant); Group PPA--polyether + 0.2% peracetic acid; Group PH--polyether + 1% sodium hypochlorite. Cast height, base and top diameter were measured and a mean value was obtained for each sample and group all data was statistically analyzed (ANOVA, p polyether impressions regardless of the disinfectant materials. It can be concluded that disinfection with the proposed agents did not produce significant alterations of the impressions and the peracetic acid could be considered a reliable material to disinfect dental molds.

Use of Clinical UV Chamber to Disinfect Dental Impressions: A Comparative Study.

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Aeran, Himanshu; Sharma, Sakshi; Kumar, Varun; Gupta, Neelu

2015-08-01

Dental impressions are potential source of infection in a prosthodontic practice. Risk of transmission of infection through saliva, blood etc is considered as hazard for both dentist as well as dental auxiliary staff. A number of methods are currently employed for disinfecting the impressions which are technique sensitive and time consuming. This study focuses on disinfecting impression using dental UV chamber which is commonly employed for storing sterilized instruments. The aim of this invitro study was to evaluate the use of clinical UV chamber to disinfect various impression materials at different time intervals and its comparison with 2% glutaraldehyde using standard immersion technique. Total sample size of 180 specimens was taken from three different impression materials. The impressions were made from 30 dentulous subjects. A total of ten impressions were made for each impression material i.e. alginate, addition silicone and polyether impression material. Six punch samples were taken from each impression. Out of 6 punch sample, one was kept as control, second was disinfected by immersing in freshly prepared 2% glutaraldehyde solution for 10 minutes and remaining four were exposed to UV rays for 3 minutes, 6 minutes, 10 minutes and 15 minutes using dental UV chamber. Amount of disinfection achieved was evaluated by counting the colonies over the culture plates with the help of digital colony. The results showed that the mean CFUs for alginate were found to be i.e. 11797.40 ± 5989.73 (mean ± SD). The mean CFUs for addition silicone impression material was found 7095.40 with a standard deviation of 4268.83 and the mean CFUs for polyether impression material was found to be 2168.92 ± 1676 (mean ± SD). For alginate and addition silicone impression material, disinfection was achieved on exposure to UV rays for a period of 10 minutes. However, for polyether impression material 3 minutes of exposure to UV rays was sufficient to cause complete disinfection.

Evaluating a new paradigm for comparing surface disinfection in clinical practice.

Science.gov (United States)

Carling, Philip C; Perkins, Jennifer; Ferguson, JoAnn; Thomasser, Anita

2014-11-01

Despite an increasing understanding of the importance of near-patient surfaces in the transmission of healthcare-associated pathogens, there remains a need to define the relative clinical effectiveness of disinfection interventions. A serial 2-phase evaluation of the clinical effectiveness of 2 surface disinfectants. A general acute care hospital. A unique system for quantifying bioburden reduction while monitoring the possible impact of differences in cleaning thoroughness was used to compare the clinical effectiveness of a traditional quaternary ammonium compound (QAC) and a novel peracetic acid/hydrogen peroxide disinfectant (ND) as part of terminal room cleaning. As a result of QAC cleaning, 93 (40%) of 237 cleaned surfaces confirmed by fluorescent marker (DAZO) removal were found to have complete removal of aerobic bioburden. During the ND phase of the study, bioburden was removed from 211 (77%) of 274 cleaned surfaces. Because there was no difference in the thoroughness of cleaning with either disinfectant (65.3% and 66.4%), the significant ([Formula: see text]) difference in bioburden reduction can be attributed to better cleaning efficacy with the ND. In the context of the study design, the ND was 1.93 times more effective in removing bacterial burden than the QAC ([Formula: see text]). Furthermore, the study design represents a new research paradigm in which 2 interventions can be compared by concomitantly and objectively analyzing both the product and process variables in a manner that can be used to define the relative effectiveness of all disinfection cleaning interventions.

Solar optics-based active panel for solar energy storage and disinfection of greywater.

Science.gov (United States)

Lee, W; Song, J; Son, J H; Gutierrez, M P; Kang, T; Kim, D; Lee, L P

2016-09-01

Smart city and innovative building strategies are becoming increasingly more necessary because advancing a sustainable building system is regarded as a promising solution to overcome the depleting water and energy. However, current sustainable building systems mainly focus on energy saving and miss a holistic integration of water regeneration and energy generation. Here, we present a theoretical study of a solar optics-based active panel (SOAP) that enables both solar energy storage and photothermal disinfection of greywater simultaneously. Solar collector efficiency of energy storage and disinfection rate of greywater have been investigated. Due to the light focusing by microlens, the solar collector efficiency is enhanced from 25% to 65%, compared to that without the microlens. The simulation of greywater sterilization shows that 100% disinfection can be accomplished by our SOAP for different types of bacteria including Escherichia coli . Numerical simulation reveals that our SOAP as a lab-on-a-wall system can resolve the water and energy problem in future sustainable building systems.

Evaluation of safety and efficacy of a new multipurpose disinfecting solution on silicone hydrogel contact lenses☆

Science.gov (United States)

Pinto-Fraga, José; Blázquez Arauzo, Francisco; Urbano Rodríguez, Rubén; González-García, María J.

2014-01-01

Purpose To evaluate the safety and efficacy of a new multipurpose disinfecting solution (MPDS) with a formulation that includes aloe vera on its composition. Methods This is a prospective, randomized, double-masked clinical trial with a crossover design that included seven examinations. Two different MPDSs, Avizor Alvera® (study solution) and All Clean Soft® (control solution), each were used for 1 month. Comfilcon A silicone hydrogel contact lenses were used during the trial. The main outcome variables were corneal staining and deposits on the surfaces of the contact lenses. Other parameters including ocular surface response, contact lens wettability, user satisfaction, and adverse events, were analyzed according to the International Organization for Standardization (ISO) 11980:2010 guidance for clinical investigation. Results Twenty subjects (10 women, 10 men) (mean age, 27.7 ± 5.6 years; range, 20–41) were included. No differences between both MPDSs were found in the percentage of subjects with corneal staining >0 at day 30 (study: 35%, control: 50%; p = 0.46); neither in the percentage of subjects with deposits on the surface of the contact lens >0 at day 30 (study: 26.32%, control: 52.63%; p = 0.18). The study MPDS received higher rates in comfort (study: 8.14 ± 1.09, control: 7.94 ± 0.92; p = 0.56) and satisfaction at day 30 (study: 8.63 ± 0.91, control: 8.29 ± 0.80; p = 0.19), however the scores were not significantly different with the control MPDS. Conclusions The clinical trial showed that the study MPDS is safe, efficient, and has acceptable physiologic tolerance, according to the ISO 11980:2010 guidance for clinical investigation. PMID:25649640

Evaluation of safety and efficacy of a new multipurpose disinfecting solution on silicone hydrogel contact lenses.

Science.gov (United States)

Pinto-Fraga, José; Blázquez Arauzo, Francisco; Urbano Rodríguez, Rubén; González-García, María J

2015-01-01

To evaluate the safety and efficacy of a new multipurpose disinfecting solution (MPDS) with a formulation that includes aloe vera on its composition. This is a prospective, randomized, double-masked clinical trial with a crossover design that included seven examinations. Two different MPDSs, Avizor Alvera® (study solution) and All Clean Soft® (control solution), each were used for 1 month. Comfilcon A silicone hydrogel contact lenses were used during the trial. The main outcome variables were corneal staining and deposits on the surfaces of the contact lenses. Other parameters including ocular surface response, contact lens wettability, user satisfaction, and adverse events, were analyzed according to the International Organization for Standardization (ISO) 11980:2010 guidance for clinical investigation. Twenty subjects (10 women, 10 men) (mean age, 27.7±5.6 years; range, 20-41) were included. No differences between both MPDSs were found in the percentage of subjects with corneal staining >0 at day 30 (study: 35%, control: 50%; p=0.46); neither in the percentage of subjects with deposits on the surface of the contact lens >0 at day 30 (study: 26.32%, control: 52.63%; p=0.18). The study MPDS received higher rates in comfort (study: 8.14±1.09, control: 7.94±0.92; p=0.56) and satisfaction at day 30 (study: 8.63±0.91, control: 8.29±0.80; p=0.19), however the scores were not significantly different with the control MPDS. The clinical trial showed that the study MPDS is safe, efficient, and has acceptable physiologic tolerance, according to the ISO 11980:2010 guidance for clinical investigation. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Reduction of Acid-Fast and Non-Acid-Fast Bacteria by Point of Use Coagulation-Flocculation-Disinfection

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Lisa M. Casanova

2015-11-01

Full Text Available Point of use (POU household water treatment is increasingly being adopted as a solution for access to safe water. Non-tuberculous Mycobacteria (NTM are found in water, but there is little research on whether NTM survive POU treatment. Mycobacteria may be removed by multi-barrier treatment systems that combine processes such as coagulation, settling and disinfection. This work evaluated removal of a non-tuberculous Mycobacterium (Mycobaterium terrae and a Gram-negative non-acid-fast environmental bacterium (Aeromonas hydrophila by combined coagulation-flocculation disinfection POU treatment. Aeromonas hydrophila showed 7.7 log10 reduction in demand free buffer, 6.8 log10 in natural surface water, and 4 log10 reduction in fecally contaminated surface water. Turbidity after treatment was <1 NTU. There was almost no reduction in levels of viable M. terrae by coagulant-flocculant-disinfectant in natural water after 30 minutes. The lack of Mycobacteria reduction was similar for both combined coagulant-flocculant-disinfectant and hypochlorite alone. A POU coagulant-flocculant-disinfectant treatment effectively reduced A. hydrophila from natural surface waters but not Mycobacteria. These results reinforce previous findings that POU coagulation-flocculation-disinfection is effective against gram-negative enteric bacteria. POU treatment and safe storage interventions may need to take into account risks from viable NTM in treated stored water and consider alternative treatment processes to achieve NTM reductions.

Calcium hypochlorite as a disinfecting additive for dental stone.

Science.gov (United States)

Twomey, Jonathan O; Abdelaziz, Khalid M; Combe, Edward C; Anderson, Dwight L

2003-09-01

Dental casts come into direct contact with impression materials and other items that are contaminated by saliva and blood from a patient's mouth, leaving the casts susceptible to cross-contamination. Topical methods of disinfecting casts are difficult to control, while immersion methods are potentially destructive. Thus, an additional method to control cross-contamination between patients and laboratory personnel is needed. This study was undertaken in an attempt to develop a dental stone with disinfecting properties and adequate compressive and tensile strengths. Calcium hypochlorite [Ca(OCl)(2)] in aqueous solution in concentrations from 0 to 1.5% was tested as a disinfecting additive to type V dental stone. The compressive and tensile strength properties of the modified stone were measured (MPa) using a universal testing machine at a consistency similar to unmodified stone. Strength data were analyzed by 1-way ANOVA and post hoc Tukey-Kramer procedure (alpha CaviCide, and 3 impressions rinsed in water served as controls. In general, the effect of adding the disinfectant to the stone was a decrease in strength. Exceptions were the dry compressive strength, for which there was a significant increase in strength (P=.048) at 0.5%, and the wet compressive and wet tensile strength, which showed no significant difference between the 1.5% and the control. When Ca(OCl)(2) was added at the concentration 0.5% (2765 ppm available chlorine), the gypsum had acceptable mechanical properties; dry compressive strength was 78.86 +/- 4.12 MPa, and dry tensile strength was 10.64 +/- 1.27 MPa, compared to control values of 67.85 +/- 6.28 and 13.41 +/- 1.24 MPa, respectively. At concentrations of 0.3% and higher (36 1650 ppm of available chlorine), calcium hypochlorite was able to completely inactivate phi29. It is possible to prepare a type V dental stone that contains a disinfectant, has adequate mechanical properties, and will reduce numbers of residual microorganisms. For example

Evaluation of Vinegar as a Disinfectant for Extracted Human Teeth - An in-Vitro Study.

Science.gov (United States)

Gogineni, Sindhuja; Ganipineni, Kiranmai; Babburi, Suresh; Venigalla, Aparna; Pinnisetti, Soujanya; Kotti, Ajay Benarji; Kalapala, Lavanya

2016-07-01

In dentistry, extracted human teeth are routinely used to learn technical and preclinical skills. Since human teeth harbour many pathogens these should be disinfected before use to minimize the risk of infections. Some commonly used disinfectants in laboratories are 10% formalin, 3% hydrogen peroxide (H2O2), 5.25% Sodium Hypochlorite (NaOCl), 70% alcohol and normal saline which have their own disadvantages like carcinogenicity, toxicity, cost effectiveness etc. Many studies have been conducted using these solutions but there is no evidence to suggest a suitable alternative for disinfecting extracted teeth. Vinegar is a sour liquid comprised mainly of acetic acid. It is cheap and commercially available shown to be effective in the prevention and control of microbial contamination. The present study was conducted for evaluation of vinegar as a disinfectant for extracted teeth. In this study a total of 40 (n=40) extracted non carious teeth were taken which were disinfected with various physical methods such as sterilization, autoclaving and chemical methods by using Vinegar, 70% Alcohol, 10% Formalin, 3% Hydrogen peroxide and 5.25% NaOCL. Later, teeth from each group were placed individually in separate test tubes containing 10ml of brain heart infusion broth at 37°C for 48 hrs to observe the evidence of growth of microorganisms. Results were analyzed using Kruskal-Wallis test. Vinegar, 10% Formalin and 3% Hydrogen peroxide were effective. The results were statistically significant with Kruskal-Wallis test value 28.053 and p-value was <0.001. Vinegar can be used as an effective disinfectant for extracted human teeth.

Sanitizers and Disinfectants Guide. Revised

Science.gov (United States)

Healthy Schools Network, Inc., 2012

2012-01-01

Sanitizers and disinfectants can play an important role in protecting public health. They are designed to kill "pests," including infectious germs and other microorganisms such as bacteria, viruses, and fungi. Unfortunately, sanitizers and disinfectants also contain chemicals that are "pesticides." Exposure to persistent toxic…

The effect of disinfectant agents on dimensional stability and surface roughness of a tissue conditioner material

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Amiralireza Khaledi

2011-01-01

Conclusion: The results showed that the disinfectant solutions used in this study did not have a significant effect on the surface quality and dimensional accuracy of Visco-gel as a functional impression material.

Fibrous Catalyst-Enhanced Acanthamoeba Disinfection by Hydrogen Peroxide.

Science.gov (United States)

Kilvington, Simon; Winterton, Lynn

2017-11-01

Hydrogen peroxide (H2O2) disinfection systems are contact-lens-patient problem solvers. The current one-step, criterion-standard version has been widely used since the mid-1980s, without any significant improvement. This work identifies a potential next-generation, one-step H2O2, not based on the solution formulation but rather on a case-based peroxide catalyst. One-step H2O2 systems are widely used for contact lens disinfection. However, antimicrobial efficacy can be limited because of the rapid neutralization of the peroxide from the catalytic component of the systems. We studied whether the addition of an iron-containing catalyst bound to a nonfunctional propylene:polyacryonitrile fabric matrix could enhance the antimicrobial efficacy of these one-step H2O2 systems. Bausch + Lomb PeroxiClear and AOSept Plus (both based on 3% H2O2 with a platinum-neutralizing disc) were the test systems. These were tested with and without the presence of the catalyst fabric using Acanthamoeba cysts as the challenge organism. After 6 hours' disinfection, the number of viable cysts was determined. In other studies, the experiments were also conducted with biofilm formed by Stenotrophomonas maltophilia and Elizabethkingia meningoseptica bacteria. Both control systems gave approximately 1-log10 kill of Acanthamoeba cysts compared with 3.0-log10 kill in the presence of the catalyst (P catalyst compared with ≥3.0-log10 kill when it was omitted. In 30 rounds' recurrent usage, the experiments, in which the AOSept Plus system was subjected to 30 rounds of H2O2 neutralization with or without the presence of catalytic fabric, showed no loss in enhanced biocidal efficacy of the material. The catalytic fabric was also shown to not retard or increase the rate of H2O2 neutralization. We have demonstrated the catalyst significantly increases the efficacy of one-step H2O2 disinfection systems using highly resistant Acanthamoeba cysts and bacterial biofilm. Incorporating the catalyst into the

Residual structure of Streptococcus mutans biofilm following complete disinfection favors secondary bacterial adhesion and biofilm re-development.

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Tatsuya Ohsumi

Full Text Available Chemical disinfection of oral biofilms often leaves biofilm structures intact. This study aimed to examine whether the residual structure promotes secondary bacterial adhesion. Streptococcus mutans biofilms generated on resin-composite disks in a rotating disc reactor were disinfected completely with 70% isopropyl alcohol, and were again cultured in the same reactor after resupplying with the same bacterial solution. Specimens were subjected to fluorescence confocal laser scanning microscopy, viable cell counts and PCR-Invader assay in order to observe and quantify secondarily adhered cells. Fluorescence microscopic analysis, particularly after longitudinal cryosectioning, demonstrated stratified patterns of viable cells on the disinfected biofilm structure. Viable cell counts of test specimens were significantly higher than those of controls, and increased according to the amount of residual structure and culture period. Linear regression analysis exhibited a high correlation between viable and total cell counts. It was concluded that disinfected biofilm structures favored secondary bacterial adhesion.

Hospital disinfection: efficacy and safety issues.

Science.gov (United States)

Dettenkofer, Markus; Block, Colin

2005-08-01

To review recent publications relevant to hospital disinfection (and cleaning) including the reprocessing of medical instruments. The key question as to whether the use of disinfectants on environmental surfaces rather than cleaning with detergents only reduces nosocomial infection rates still awaits conclusive studies. New disinfectants, mainly peroxygen compounds, show good sporicidal properties and will probably replace more problematical substances such as chlorine-releasing agents. The safe reprocessing of medical devices requires a well-coordinated approach, starting with proper cleaning. New methods and substances show promising activity for preventing the transmission of prions. Different aspects of virus inactivation have been studied, and the transmissibility, e.g. of norovirus, shows the need for sound data on how different disinfectant classes perform. Biofilms or other forms of surface-adherent organisms pose an extraordinary challenge to decontamination. Although resistance to biocides is generally not judged to be as critical as antibiotic resistance, scientific data support the need for proper use, i.e. the avoidance of widespread application, especially in low concentrations and in consumer products. Chemical disinfection of heat-sensitive instruments and targeted disinfection of environmental surfaces are established components of hospital infection control. To avoid danger to staff, patients and the environment, prudent use as well as established safety precautions are required. New technologies and products should be evaluated with sound methods. As emerging resistant pathogens will challenge healthcare facilities in the future even more than at present, there is a need for well-designed studies addressing the role of disinfection in hospital infection control.

The role of surface disinfection in infection prevention

Science.gov (United States)

Gebel, Jürgen; Exner, Martin; French, Gary; Chartier, Yves; Christiansen, Bärbel; Gemein, Stefanie; Goroncy-Bermes, Peter; Hartemann, Philippe; Heudorf, Ursel; Kramer, Axel; Maillard, Jean-Yves; Oltmanns, Peter; Rotter, Manfred; Sonntag, Hans-Günther

2013-01-01

Background: The Rudolf Schuelke Foundation addresses topics related to hygiene, infection prevention and public health. In this context a panel of scientists from various European countries discussed “The Role of Surface Disinfection in Infection Prevention”. The most important findings and conclusions of this meeting are summarised in the present consensus paper. Aim: Although the relevance of surface disinfection is increasingly being accepted, there are still a number of issues which remain controversial. In particular, the following topics were addressed: Transferral of microbes from surface to patients as a cause of infection, requirements for surface disinfectants, biocidal resistance and toxicity, future challenges. Methods and findings: After discussion and review of current scientific literature the authors agreed that contaminated surfaces contribute to the transmission of pathogens and may thus pose an infection hazard. Targeted surface disinfection based on a risk profile is seen as an indispensable constituent in a multibarrier approach of universal infection control precautions. Resistance and cross-resistance depend on the disinfectant agent as well as on the microbial species. Prudent implementation of surface disinfection regimens tested to be effective can prevent or minimize adverse effects. Conclusions: Disinfection must be viewed as a holistic process. There is a need for defining standard principles for cleaning and disinfection, for ensuring compliance with these principles by measures such as written standard operating procedures, adequate training and suitable audit systems. Also, test procedures must be set up in order to demonstrate the efficacy of disinfectants including new application methods such as pre-soaked wipes for surface disinfection. PMID:23967396

The role of surface disinfection in infection prevention

Directory of Open Access Journals (Sweden)

Gebel, Jürgen

2013-04-01

Full Text Available [english] Background: The Rudolf Schuelke Foundation addresses topics related to hygiene, infection prevention and public health. In this context a panel of scientists from various European countries discussed “The Role of Surface Disinfection in Infection Prevention”. The most important findings and conclusions of this meeting are summarised in the present consensus paper.Aim: Although the relevance of surface disinfection is increasingly being accepted, there are still a number of issues which remain controversial. In particular, the following topics were addressed: Transferral of microbes from surface to patients as a cause of infection, requirements for surface disinfectants, biocidal resistance and toxicity, future challenges.Methods and findings: After discussion and review of current scientific literature the authors agreed that contaminated surfaces contribute to the transmission of pathogens and may thus pose an infection hazard. Targeted surface disinfection based on a risk profile is seen as an indispensable constituent in a multibarrier approach of universal infection control precautions. Resistance and cross-resistance depend on the disinfectant agent as well as on the microbial species. Prudent implementation of surface disinfection regimens tested to be effective can prevent or minimize adverse effects.Conclusions: Disinfection must be viewed as a holistic process. There is a need for defining standard principles for cleaning and disinfection, for ensuring compliance with these principles by measures such as written standard operating procedures, adequate training and suitable audit systems. Also, test procedures must be set up in order to demonstrate the efficacy of disinfectants including new application methods such as pre-soaked wipes for surface disinfection.

Potential Impact of the Resistance to Quaternary Ammonium Disinfectants on the Persistence of Listeria monocytogenes in Food Processing Environments.

Science.gov (United States)

Martínez-Suárez, Joaquín V; Ortiz, Sagrario; López-Alonso, Victoria

2016-01-01

The persistence of certain strains of Listeria monocytogenes, even after the food processing environment has been cleaned and disinfected, suggests that this may be related to phenomena that reduce the concentration of the disinfectants to subinhibitory levels. This includes (i) the existence of environmental niches or reservoirs that are difficult for disinfectants to reach, (ii) microorganisms that form biofilms and create microenvironments in which adequate concentrations of disinfectants cannot be attained, and (iii) the acquisition of resistance mechanisms in L. monocytogenes, including those that lead to a reduction in the intracellular concentration of the disinfectants. The only available data with regard to the resistance of L. monocytogenes to disinfectants applied in food production environments refer to genotypic resistance to quaternary ammonium compounds (QACs). Although there are several well-characterized efflux pumps that confer resistance to QACs, it is a low-level resistance that does not generate resistance to QACs at the concentrations applied in the food industry. However, dilution in the environment and biodegradation result in QAC concentration gradients. As a result, the microorganisms are frequently exposed to subinhibitory concentrations of QACs. Therefore, the low-level resistance to QACs in L. monocytogenes may contribute to its environmental adaptation and persistence. In fact, in certain cases, the relationship between low-level resistance and the environmental persistence of L. monocytogenes in different food production chains has been previously established. The resistant strains would have survival advantages in these environments over sensitive strains, such as the ability to form biofilms in the presence of increased biocide concentrations.

Genotoxicity of the disinfection by-products resulting from peracetic acid- or hypochlorite-disinfected sewage wastewater.

Science.gov (United States)

Crebelli, R; Conti, L; Monarca, S; Feretti, D; Zerbini, I; Zani, C; Veschetti, E; Cutilli, D; Ottaviani, M

2005-03-01

Wastewater disinfection is routinely carried out to prevent the spread of human pathogens present in wastewater effluents. To this aim, chemical and physical treatments are applied to the effluents before their emission in water bodies. In this study, the influence of two widely used disinfectants, peracetic acid (PAA) and sodium hypochlorite (NaClO), on the formation of mutagenic by-products was investigated. Wastewater samples were collected before and after disinfection, in winter and in summer, at a pilot plant installed in a municipal wastewater-treatment plant. Samples were adsorbed using silica C18 cartridges and the concentrates were tested for mutagenicity in the Salmonella typhimurium reversion test with strains TA98 and TA100. Non-concentrated water samples were tested with two plant genotoxicity assays (the Allium cepa root anaphase aberration test and the Tradescantia/micronucleus test). Mutagenicity assays in bacteria and in Tradescantia showed borderline mutagenicity in some of the wastewater samples, independent of the disinfection procedure applied. Negative results were obtained in the A. cepa anaphase aberration test. These results indicate that, in the conditions applied, wastewater disinfection with PAA and NaClO does not lead to the formation of significant amounts of genotoxic by-products.

[DESIDENT CaviCide a new disinfectant].

Science.gov (United States)

Severa, J; Klaban, V

2009-01-01

The properties of the new disinfection agent DESIDENT CaviCide, such as characteristics, disinfection efficiency, biological degradability and ecotoxicity are described. Also areas and forms of usage this biocidal agent are mentioned.

Solar water disinfection (SODIS): A review from bench-top to roof-top

International Nuclear Information System (INIS)

McGuigan, Kevin G.; Conroy, Ronán M.; Mosler, Hans-Joachim; Preez, Martella du; Ubomba-Jaswa, Eunice; Fernandez-Ibañez, Pilar

2012-01-01

Graphical abstract: . Water being treated by solar disinfection outside a primary school classroom in Southern Uganda. Students fill their bottles at home and expose them to the sun while they are at school. Highlights: ► A thorough review of current state of play of solar water disinfection. ► An examination of both laboratory and field studies. ► Description of the economic and behaviour change aspects of this technology. - Abstract: Solar water disinfection (SODIS) has been known for more than 30 years. The technique consists of placing water into transparent plastic or glass containers (normally 2 L PET beverage bottles) which are then exposed to the sun. Exposure times vary from 6 to 48 h depending on the intensity of sunlight and sensitivity of the pathogens. Its germicidal effect is based on the combined effect of thermal heating of solar light and UV radiation. It has been repeatedly shown to be effective for eliminating microbial pathogens and reduce diarrhoeal morbidity including cholera. Since 1980 much research has been carried out to investigate the mechanisms of solar radiation induced cell death in water and possible enhancement technologies to make it faster and safer. Since SODIS is simple to use and inexpensive, the method has spread throughout the developing world and is in daily use in more than 50 countries in Asia, Latin America, and Africa. More than 5 million people disinfect their drinking water with the solar disinfection (SODIS) technique. This review attempts to revise all relevant knowledge about solar disinfection from microbiological issues, laboratory research, solar testing, up to and including real application studies, limitations, factors influencing adoption of the technique and health impact.

Ultraviolet disinfection of potable water

Energy Technology Data Exchange (ETDEWEB)

Wolfe, R. L. [Metropolitan Water District of Southern California, Los Angeles, CA (United States)

1990-06-15

Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection.

Ultraviolet disinfection of potable water

International Nuclear Information System (INIS)

Wolfe, R.L.

1990-01-01

Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection

9 CFR 83.7 - Shipping containers; cleaning and disinfection.

Science.gov (United States)

2010-01-01

... HEMORRHAGIC SEPTICEMIA § 83.7 Shipping containers; cleaning and disinfection. (a) All live fish that are to be... been cleaned and disinfected. (1) Cleaning and disinfection of shipping containers must be monitored by... who issues the ICI. (2) Cleaning and disinfection must be sufficient to neutralize any VHS virus to...

A bacteriological study of hospital beds before and after disinfection with phenolic disinfectant

OpenAIRE

Denise de Andrade; Emília L. S. Angerami; Carlos Roberto Padovani

2000-01-01

In hospitals, one of the ways to control microbial contamination is by disinfecting the furniture used by patients. This study's main objective was to evaluate the microbiological condition of hospital mattresses before and after such disinfection, in order to identify bacteria that are epidemiologically important in nosocomial infection, such as Staphylococcus aureus and Pseudomonas aeruginosa. RODAC plates with two different culture media were used to collect specimens. Patient beds were se...

Peracetic Acid as a Green Disinfectant for Combined Sewer ...

Science.gov (United States)

This cooperative research and development agreement between U.S. EPA, Solvay, MSDGC, and CB&I is evaluating the potential of PAA for disinfection of Muddy Creek CSO wastewater and comparing that with sodium hypochlorite disinfection. This presentation will document the effectiveness of sodium hypochlorite and PAA for the inactivation of E. coli in CSO wastewater using laboratory bench-scale jar tests and Muddy Creek field site studies based on the following items:•Storage, shelf life, and application of the disinfectants.•Effectiveness of the disinfectants in the inactivation of E. coli.•Formation of harmful byproducts by the disinfectants.•Operation and maintenance costs, including the cost of the disinfectant, its storage, application, and neutralizing agent for the disinfectant to maintain the Ohio EPA guideline for residual disinfectant at the discharge point. Like many cities in the USA, Cincinnati, Ohio is attempting to find the best way to meet state and federal requirements concerning combined sewer overflow (CSO) wastewater. The Muddy Creek CSO treatment facility was constructed to provide treatment for CSO Numbers 198 and 216 from the Westwood Trunk sewer. The Metropolitan Sewer District of Greater Cincinnati (MSDGC) is currently using sodium hypochlorite for disinfection in this treatment facility. Because of degradation of hypochlorite during storage and the formation of chlorinated disinfection byproducts (DBPs), MSDGC is evaluating alternat

40 CFR 141.172 - Disinfection profiling and benchmarking.

Science.gov (United States)

2010-07-01

... benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Disinfection-Systems Serving 10,000 or More People § 141.172 Disinfection profiling and benchmarking. (a... sanitary surveys conducted by the State. (c) Disinfection benchmarking. (1) Any system required to develop...

Disinfectant effect of Methylated Ethanol against Listeria species

Directory of Open Access Journals (Sweden)

Y Yakubu

2012-04-01

Full Text Available This study was carried out in order to determine the disinfectant effect of Methylated spirit® (95% methanol and 5% ethanol as a teat dip against Listeria species. Hand milking was employed to collect 576 (288 x 2 raw milk samples from different lactating cows within Sokoto metropolis (Nigeria. 288 samples were collected before disinfecting the udder teats with Methylated spirit®, while the other 288 were collected after disinfection with Methylated spirit®. The samples were analyzed using selective culture and isolation technique in which the 288 samples collected before disinfection, 114 (39.6% were positive for Listeria species. Among the positive samples 44 (38.6% were Listeria innocua, 16 (14.0% Listeria ivanovii, 36 (31.6% Listeria monocytogenes, 11 (9.6% Listeria welshimeri and 7 (6.1% Listeria seeligeri, while none of the 288 samples collected after disinfection was positive. The study has shown high prevalence of Listeria species in milk collected without washing/disinfecting the teats and has also established the sensitivity of Listeria species to methylated ethanol which can be used as dip for disinfecting udder teats before milking in order to prevent contamination with Listeria species and other methylated spirit-sensitive organisms. This study is essential to educate Fulani herdsmen and other milk handlers on the importance of disinfecting udder teats before milking. [Vet. World 2012; 5(2.000: 91-93

Candida auris: Disinfectants and Implications for Infection Control.

Science.gov (United States)

Ku, Tsun S N; Walraven, Carla J; Lee, Samuel A

2018-01-01

Candida auris is a rapidly emerging pathogen and is able to cause severe infections with high mortality rates. It is frequently misidentified in most clinical laboratories, thus requiring more specialized identification techniques. Furthermore, several clinical isolates have been found to be multidrug resistant and there is evidence of nosocomial transmission in outbreak fashion. Appropriate infection control measures will play a major role in controlling the management and spread of this pathogen. Unfortunately, there are very few data available on the effectiveness of disinfectants against C. auris . Chlorine-based products appear to be the most effective for environmental surface disinfection. Other disinfectants, although less effective than chlorine-based products, may have a role as adjunctive disinfectants. A cleaning protocol will also need to be established as the use of disinfectants alone may not be sufficient for maximal decontamination of patient care areas. Furthermore, there are fewer data on the effectiveness of antiseptics against C. auris for patient decolonization and hand hygiene for healthcare personnel. Chlorhexidine gluconate has shown some efficacy in in vitro studies but there are reports of patients with persistent colonization despite twice daily body washes with this disinfectant. Hand hygiene using soap and water, with or without chlorhexidine gluconate, may require the subsequent use of alcohol-based hand sanitizer for maximal disinfection. Further studies will be needed to validate the currently studied disinfectants for use in real-world settings.

Disinfection aboard cruise liners and naval units: formation of disinfection by-products using chlorine dioxide in different qualities of drinking water.

Science.gov (United States)

Ufermann, Petra; Petersen, Hauke; Exner, Martin

2011-12-01

The world-wide deployment of cruise liners and naval units has caused an increased need for the disinfection of drinking water. The main cause for this is the unknown quality of drinking water in foreign harbours--besides the formation of bio-films due to the climatically disadvantageous conditions in the operational area. Water conduits on board are currently disinfected with calcium hypochlorite in case of microbiological contamination. Chemical and physical analyses after disinfection with calcium hypochlorite have shown that organic by-products consisting of trihalomethanes develop in considerable amounts during disinfection. Furthermore, the method is susceptible to handling errors and thus often leads to insufficient disinfection results. Hitherto, the use of other disinfection methods allowed by government regulations, especially chlorine dioxide, is not widely spread. Unlike disinfection with calcium hypochlorite, chlorine dioxide does not lead to the formation of trihalomethanes. Typical disinfection by-products (DBP) are the anions chlorite and chlorate, which are formed in oxidative processes. The formation conditions of these anions have not yet been elucidated. For this reason, the probability of the generation of inorganic by-products after disinfection with chlorine dioxide has been determined, and their occurrence in drinking water on board has been examined with respect to a possible correlation between water quality and the formation of chlorate and chlorite. Therefore, a chromatographic method was developed and validated in order to determine the periodical development of chlorate and chlorite from chorine dioxide in purified water at different pH-values as well as in actual drinking water samples from water conduits on board. The formation of the by-products chlorite and chlorate after disinfection with chlorine dioxide is influenced neither by pH-value nor by chemical properties of the disinfected water. Considering the examined conditions

Comparative evaluation of tensile strength of Gutta-percha cones with a herbal disinfectant.

Science.gov (United States)

Mahali, Raghunandhan Raju; Dola, Binoy; Tanikonda, Rambabu; Peddireddi, Suresh

2015-01-01

To evaluate and compare the tensile strength values and influence of taper on the tensile strength of Gutta-percha (GP) cones after disinfection with sodium hypochlorite (SH) and Aloe vera gel (AV). Sixty GP cones of size 110, 2% taper, 60 GP cones F3 ProTaper, and 60 GP of size 30, 6% taper were obtained from sealed packs as three different groups. Experimental groups were disinfected with 5.25% SH and 90% AV gel except the control group. Tensile strengths of GP were measured using the universal testing machine. The mean tensile strength values for Group IA, IIA and IIIA are 11.8 MPa, 8.69 MPa, and 9.24 MPa, respectively. Results were subjected to statistical analysis one-way analysis of variance test and Tukey post-hoc test. 5.25% SH solutions decreased the tensile strength of GP cones whereas with 90% AV gel it was not significantly altered. Ninety percent Aloe vera gel as a disinfectant does not alter the tensile strength of GP cones.

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.

Science.gov (United States)

Boyce, John M; Guercia, Kerri A; Sullivan, Linda; Havill, Nancy L; Fekieta, Renee; Kozakiewicz, Janet; Goffman, David

2017-09-01

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 χ 2 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. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Disinfection of municipal water using solar radiation: an economical approach for rural dwellers in the coastal region of Karachi

International Nuclear Information System (INIS)

Ahmed, M.F.; Saleem, M.

2010-01-01

At present acquiring safe drinking water in rural or remote areas of Pakistan is a challenging task for dwellers. Coast line of Karachi is a sporadic habitat of villages not having access to safe drinking water. Many incidents of waterborne diseases have been reported in that area and attributed to contaminated municipal water supply. Solution of the problem is disinfection however, general methods of water disinfection such as boiling, UV-lamp, ozonation and chemical additive are costly or require skilled manpower. Present study investigates the solar disinfection method to treat municipal water supply at Karachi Institute of Power Engineering (KINPOE) located at the coastal belt of Karachi. Effect of exposure time, bottle material and turbidity of water on the process performance was evaluated. Model indicator bacteria total coliform (TC) was used to evaluate the solar disinfection process. Study revealed that in order to disinfect the municipal water, samples should be filled in PET transparent bottles, having turbidity below 23 NTU, and expose to solar radiation in the study area at least for one hour. Study shows that solar disinfection may provide safe drinking water meeting national and international water quality standards at minimum cost and effort in sunshine rich areas and not having access to other water purification systems. (author)

Peracetic acid for secondary effluent disinfection: a comprehensive performance assessment.

Science.gov (United States)

Antonelli, M; Turolla, A; Mezzanotte, V; Nurizzo, C

2013-01-01

The paper is a review of previous research on secondary effluent disinfection by peracetic acid (PAA) integrated with new data about the effect of a preliminary flash-mixing step. The process was studied at bench and pilot scale to assess its performance for discharge in surface water and agricultural reuse (target microorganisms: Escherichia coli and faecal coliform bacteria). The purposes of the research were: (1) determining PAA decay and disinfection kinetics as a function of operating parameters, (2) evaluating PAA suitability as a disinfectant, (3) assessing long-term disinfection efficiency, (4) investigating disinfected effluent biological toxicity on some aquatic indicator organisms (Vibrio fischeri, Daphnia magna and Selenastrum capricornutum), (5) comparing PAA with conventional disinfectants (sodium hypochlorite, UV irradiation). PAA disinfection was capable of complying with Italian regulations on reuse (10 CFU/100 mL for E. coli) and was competitive with benchmarks. No regrowth phenomena were observed, as long as needed for agricultural reuse (29 h after disinfection), even at negligible concentrations of residual disinfectant. The toxic effect of PAA on the aquatic environment was due to the residual disinfectant in the water, rather than to chemical modification of the effluent.

[Experimental evaluation of the spraying disinfection efficiency on dental models].

Science.gov (United States)

Zhang, Yi; Fu, Yuan-fei; Xu, Kan

2013-08-01

To evaluate the disinfect effect after spraying a new kind of disinfectant on the dental plaster models. The germ-free plaster samples, which were smeared with bacteria compound including Staphylococcus aureus, Escherichia coli, Saccharomyces albicans, Streptococcus mutans and Actinomyces viscosus were sprayed with disinfectants (CaviCide) and glutaraldehyde individually. In one group(5 minutes later) and another group(15 minutes later), the colonies were counted for statistical analysis after sampling, inoculating, and culturing which were used for evaluation of disinfecting efficiency. ANOVA was performed using SPSS12.0 software package. All sample bacteria were eradicated after spraying disinfectants(CaviCide) within 5 minutes and effective bacteria control was retained after 15 minutes. There was significant difference between the disinfecting efficiency of CaviCide and glutaraldehyde. The effect of disinfection with spraying disinfectants (CaviCide) on dental models is quick and effective.

Solar water disinfection (SODIS): A review from bench-top to roof-top

Energy Technology Data Exchange (ETDEWEB)

McGuigan, Kevin G., E-mail: kmcguigan@rcsi.ie [Royal College of Surgeons in Ireland, Dublin 2 (Ireland); Conroy, Ronan M. [Royal College of Surgeons in Ireland, Dublin 2 (Ireland); Mosler, Hans-Joachim [EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133: CH-8600 Duebendorf (Switzerland); Preez, Martella du; Ubomba-Jaswa, Eunice [CSIR, Natural Resources and the Environment, Pretoria, Gauteng (South Africa); Fernandez-Ibanez, Pilar [Plataforma Solar de Almeria - CIEMAT, P.O. Box 22, 07200 Tabernas, Almeria (Spain)

2012-10-15

Graphical abstract: . Water being treated by solar disinfection outside a primary school classroom in Southern Uganda. Students fill their bottles at home and expose them to the sun while they are at school. Highlights: Black-Right-Pointing-Pointer A thorough review of current state of play of solar water disinfection. Black-Right-Pointing-Pointer An examination of both laboratory and field studies. Black-Right-Pointing-Pointer Description of the economic and behaviour change aspects of this technology. - Abstract: Solar water disinfection (SODIS) has been known for more than 30 years. The technique consists of placing water into transparent plastic or glass containers (normally 2 L PET beverage bottles) which are then exposed to the sun. Exposure times vary from 6 to 48 h depending on the intensity of sunlight and sensitivity of the pathogens. Its germicidal effect is based on the combined effect of thermal heating of solar light and UV radiation. It has been repeatedly shown to be effective for eliminating microbial pathogens and reduce diarrhoeal morbidity including cholera. Since 1980 much research has been carried out to investigate the mechanisms of solar radiation induced cell death in water and possible enhancement technologies to make it faster and safer. Since SODIS is simple to use and inexpensive, the method has spread throughout the developing world and is in daily use in more than 50 countries in Asia, Latin America, and Africa. More than 5 million people disinfect their drinking water with the solar disinfection (SODIS) technique. This review attempts to revise all relevant knowledge about solar disinfection from microbiological issues, laboratory research, solar testing, up to and including real application studies, limitations, factors influencing adoption of the technique and health impact.

[Control of disinfection in buildings used for poultry raising].

Science.gov (United States)

Maris, P

1989-01-01

During a 2-year survey in turkey breeding farms, it was possible to compare six disinfection procedures by monitoring 14 first disinfections following the breeding house cleaning and 14 second disinfections prior to animal return. By swabbing all the germs from asbestos concrete surfaces, we noted that in the case of first disinfection the chloramine T-based product was more effective than phenol or quaternary ammonium-aldehyde-based products. For the second disinfection, it was demonstrated that a minimal dose of 15 kg of formaldehyde was necessary for disinfection to be satisfactory; 12 to 15 kg paraformaldehyde was as effective as 40 to 60 liters of 30-35% formol for buildings, the ground surface of which covered between 1,000 and 1,300 m2.

Chemical aspects of peracetic acid based wastewater disinfection ...

African Journals Online (AJOL)

Peracetic acid (PAA) has been studied for wastewater disinfection applications for some 30 years and has been shown to be an effective disinfectant against many indicator microbes, including bacteria, viruses, and protozoa. One of the key advantages compared to, e.g., chlorine is the lack of harmful disinfection ...

Effects of some antiseptics and disinfectants on Staphylococcus ...

African Journals Online (AJOL)

A total of 6 antiseptics and disinfectants at varying concentrations (20% - 100%) and contact time (10-60 minutes) were tested for the efficacy in the reduction of Staphylococcus aureus isolated from the hands of volunteers. Disinfectant 1 was the most effective disinfectant being bactericidal to S. aureus at 100% ...

Candida auris: Disinfectants and Implications for Infection Control

Directory of Open Access Journals (Sweden)

Tsun S. N. Ku

2018-04-01

Full Text Available Candida auris is a rapidly emerging pathogen and is able to cause severe infections with high mortality rates. It is frequently misidentified in most clinical laboratories, thus requiring more specialized identification techniques. Furthermore, several clinical isolates have been found to be multidrug resistant and there is evidence of nosocomial transmission in outbreak fashion. Appropriate infection control measures will play a major role in controlling the management and spread of this pathogen. Unfortunately, there are very few data available on the effectiveness of disinfectants against C. auris. Chlorine-based products appear to be the most effective for environmental surface disinfection. Other disinfectants, although less effective than chlorine-based products, may have a role as adjunctive disinfectants. A cleaning protocol will also need to be established as the use of disinfectants alone may not be sufficient for maximal decontamination of patient care areas. Furthermore, there are fewer data on the effectiveness of antiseptics against C. auris for patient decolonization and hand hygiene for healthcare personnel. Chlorhexidine gluconate has shown some efficacy in in vitro studies but there are reports of patients with persistent colonization despite twice daily body washes with this disinfectant. Hand hygiene using soap and water, with or without chlorhexidine gluconate, may require the subsequent use of alcohol-based hand sanitizer for maximal disinfection. Further studies will be needed to validate the currently studied disinfectants for use in real-world settings.

Application of a high-level peracetic acid disinfection protocol to re-process antibiotic disinfected skin allografts.

Science.gov (United States)

Lomas, R J; Huang, Q; Pegg, D E; Kearney, J N

2004-01-01

Skin allografts, derived from cadaveric donors, are widely used for the treatment of burns and ulcers. Prior to use in clinical situations, these allografts are disinfected using a cocktail of antibiotics and then cryopreserved. Unfortunately, this antibiotic disinfection procedure fails to decontaminate a significant proportion and these contaminated grafts can not be used clinically. We have investigated whether it is possible to apply a second, more potent disinfection procedure to these contaminated grafts and effectively to re-process them for clinical use. Cadaveric skin grafts, treated with antibiotics and cryopreserved, were thawed and a peracetic acid (PAA) disinfection protocol applied. The grafts were then preserved in a high concentration of glycerol or propylene glycol, and properties thought to be essential for successful clinical performance assessed. The cytotoxicity of the grafts was assessed using both extract and contact assays; damage to the skin collagen was assessed using a collagenase susceptibility assay and the capacity of the grafts to elicit an inflammatory response in vitro was assessed by quantifying the production of the pro-inflammatory cytokine TNF-alpha by human peripheral blood mononuclear phagocytes. PAA disinfection, in conjunction with either glycerol or propylene glycol preservation, did not render the grafts cytotoxic, pro-inflammatory, or increase their susceptibility to collagenase digestion. The rates of penetration of glycerol and propylene glycol into the re-processed skin were comparable to those of fresh skin. This study has demonstrated that PAA disinfection combined with immersion in high concentrations of either glycerol or propylene glycol was an effective method for re-processing contaminated skin allografts, and may justify their clinical use.

9 CFR 52.7 - Disinfection of premises, conveyances, and materials.

Science.gov (United States)

2010-01-01

... cleaning and disinfection, unless an official pseudorabies epidemiologist determines that a shorter or... and disinfection, except for cleaning and disinfection of the conveyances used to transport the swine... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of premises, conveyances...

Chemical disinfection of non-porous inanimate surfaces experimentally contaminated with four human pathogenic viruses.

Science.gov (United States)

Sattar, S A; Springthorpe, V S; Karim, Y; Loro, P

1989-06-01

The chemical disinfection of virus-contaminated non-porous inanimate surfaces was investigated using coxsackievirus B3, adenovirus type 5, parainfluenza virus type 3 and coronavirus 229E as representatives of important nosocomial viral pathogens. A 10 microliter amount of the test virus, suspended in either faeces or mucin, was placed onto each stainless steel disk (about 1 cm in diameter) and the inoculum allowed to dry for 1 h under ambient conditions. Sixteen disinfectant formulations were selected for this study based on the findings of an earlier investigation with a human rotavirus. After 1 min exposure to 20 microliters of the disinfectant, the virus from the disks was immediately eluted into tryptose phosphate broth and plaque assayed. Using an efficacy criterion of a 3 log10 or greater reduction in virus infectivity titre and irrespective of the virus suspending medium, only the following five disinfectants proved to be effective against all the four viruses tested: (1) 2% glutaraldehyde normally used as an instrument soak, (2) a strongly alkaline mixture of 0.5% sodium o-benzyl-p-chlorophenate and 0.6% sodium lauryl sulphate, generally used as a domestic disinfectant cleaner for hard surfaces, (3) a 0.04% solution of a quaternary ammonium compound containing 7% hydrochloric acid, which is the basis of many toilet bowl cleaners, (4) chloramine T at a minimum free chlorine level of 3000 p.p.m. and (5) sodium hypochlorite at a minimum free chlorine concentration of 5000 p.p.m. Of those chemicals suitable for use as topical antiseptics, 70% ethanol alone or products containing at least 70% ethanol were ineffective only against coxsackievirus B3. These results emphasize the care needed in selecting chemical disinfectants for routine use in infection control.

How clean is your scope? A completed audit cycle of the disinfection of nasendoscopes

Science.gov (United States)

Lakhani, Raj; Smithard, Abigail; Bleach, Nigel

2010-01-01

INTRODUCTION Correct disinfection of nasendoscopes is essential to address both the potential iatrogenic transmission of infection and to avoid injury from the chemicals used. MATERIALS AND METHODS Standards-based audit of the disinfection of nasendoscopes against the ENT UK guidelines, ervention: instructional poster and staff training session. The disinfection process was re-audited one month later. RESULTS A total of 10 sessions and 31 cleaning episodes were audited in the first cycle (C1). A total of 12 sessions and 36 cleaning episodes were re-audited in the second cycle (C2). Clinic set-up results: there was a marked improvement in the checking of the expiry date (C1 = 5/10; C2 = 10/12; P ≤ 0.001) and recording the date for the solution to be discarded (C1 = 0/10; C2 = 10/12; P ≤ 0.048). Each cleaning episode results: an improvement in transportation in a ‘dirty bag’ (C1 = 0/31; C2 = 19/36; P ≤ 0.001), washing of the scope (C1 = 0/31; C2 = 36/36; P ≤ 0.001), adequate disinfection time (C1 = 16/31; C2 = 33/36; P≤ 0.001), rinsing and drying with alcohol swab (C1 = 0/31; C2 = 35/36; P ≤ 0.001) and placing of the scope in a ‘clean bag’ for storage (C1 = 0/31; C2 = 35/36; P ≤ 0.001) was seen after the intervention. CONCLUSIONS The introduction of a poster and training in the disinfection of nasendoscopes proved successful in improving compliance with the published guidelines. These simple measures were simple, cheap and effective to institute. The benefit of improving the disinfection of nasendoscopes to patients, doctors and the organisations that they work in is clear. PMID:20883605

Inactivation of an enterovirus by airborne disinfectants

Science.gov (United States)

2013-01-01

Background The activity of airborne disinfectants on bacteria, fungi and spores has been reported. However, the issue of the virucidal effect of disinfectants spread by fogging has not been studied thoroughly. Methods A procedure has been developed to determine the virucidal activity of peracetic acid-based airborne disinfectants on a resistant non-enveloped virus poliovirus type 1. This virus was laid on a stainless carrier. The products were spread into the room by hot fogging at 55°C for 30 minutes at a concentration of 7.5 mL.m-3. Poliovirus inoculum, supplemented with 5%, heat inactivated non fat dry organic milk, were applied into the middle of the stainless steel disc and were dried under the air flow of a class II biological safety cabinet at room temperature. The Viral preparations were recovered by using flocked swabs and were titered on Vero cells using the classical Spearman-Kärber CPE reading method, the results were expressed as TCID50.ml-1. Results The infectious titer of dried poliovirus inocula was kept at 105 TCID50.mL-1 up to 150 minutes at room temperature. Dried inocula exposed to airborne peracetic acid containing disinfectants were recovered at 60 and 120 minutes post-exposition and suspended in culture medium again. The cytotoxicity of disinfectant containing medium was eliminated through gel filtration columns. A 4 log reduction of infectious titer of dried poliovirus inocula exposed to peracetic-based airborne disinfectant was obtained. Conclusion This study demonstrates that the virucidal activity of airborne disinfectants can be tested on dried poliovirus. PMID:23587047

9 CFR 55.4 - Disinfection of premises, conveyances, and materials.

Science.gov (United States)

2010-01-01

... paid will be responsible for expenses incurred in connection with the cleaning and disinfection, except that APHIS or a State will pay for cleaning and disinfection of the conveyances used to transport the... disinfecting premises when the procedures needed to conduct effective cleaning and disinfection are unusually...

Stethoscope disinfection campaign in a Nigerian teaching hospital:results of a before-and-after study.

Science.gov (United States)

Uneke, Chigozie J; Ndukwe, Chinwendu D; Nwakpu, Kingsley O; Nnabu, Richard C; Ugwuoru, Cletus D; Prasopa-Plaizier, Nittita

2014-01-15

This study aimed to assess the impact of a stethoscope disinfection sensitization campaign among doctors and nurses in a Nigerian teaching hospital. The design was a before-and-after study. Pre-program measurements were used to provide a baseline against which the post-program results were compared. Interventions that promoted compliance with stethoscope disinfection practice that were implemented included training and education on stethoscope disinfection and introduction of 70% isopropyl alcohol disinfectant at points-of-care places. Microbiological assessment of stethoscopes used by health workers was conducted after the intervention and the outcome was compared with the pilot study results. After the intervention, of the 89 stethoscopes screened, 18 (20.2%) were contaminated with bacterial agents. A higher prevalence of stethoscope contamination was observed among stethoscopes from the intensive care unit (66.7%), the VIP unit (50%), and the antenatal unit (37.5%). The main isolates were Staphylococcus aureus (44.4%) and Escherichia coli (50%). The antibiotic sensitivity assessment indicated that the bacterial isolates were resistant to nearly all the antibiotics tested. All the 89 health workers whose stethoscopes were screened after the intervention admitted to cleaning their stethoscopes after seeing each patient, representing a compliance rate of 100%, unlike the 15% compliance at the pilot phase. The baseline stethoscope contamination rate was 78.5% versus 20.2% post-intervention. Training and education and introduction of alcohol-based disinfectants inexpensive but very effective methods to improve stethoscope disinfection compliance among health workers in low-income settings.

[Sensitivity to disinfectants of Candid albicans strains isolated from the hospital environment].

Science.gov (United States)

Tadeusiak, B

1998-01-01

In recent years an increase of the incidence of Candida infections caused mainly by C. albicans strains especially in high risk inpatients with neoplasms, decreased immunity, burns and after treatment with multiple antibiotics has been observed. Candida organisms are particularly dangerous for newborns being responsible for about 30% of septicaemia cases in newborns in intensive care units. Fungal infections can be endogenous in origin but exogenous infection sources occur in hospitals. The cause of the latter are errors in aseptic management and insufficiently disinfected medical instruments and equipment. The purpose of the study was a comparison of the sensitivity to disinfectants of C. albicans belonging to two laboratory strains C. albicans PZH and C. albicans ATCC 10231 used for the determination of concentrations of two disinfectants used. Besides that, this sensitivity was determined in 14 strains isolated from the patients and one from the circuit of dialysis solution supply to artificial kidney. The study was carried out by the qualitative suspension method, in which the cells in the fluid were subjected to the action of disinfectants, and by the carrier method in which the cells of the microorganisms were present on the surface of metal cylinders. By the suspension method the sensitivity was determined to chloramine T in concentrations from 5.0% to 0.001%, formalin from 10.0% to 0.25%, glutaraldehyde from 2.0% to 0.1%, Septyl from 3.5% to 0.25%. The exposure time was 5, 10, 15, 30 and 60 minutes. The tested strains differed in their sensitivity to the disinfectants used. The greatest interstrain differences were observed in the sensitivity to the disinfectants used. The greatest interstrain differences were observed in the sensitivity to chloramine T. The highest concentrations were tolerated by the strains isolated from the patients and from the artificial kidney circuit as well as by the standard strain ATCC 10231. In the 10-minute exposure time

Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa (P. aeruginosa) biofilm

Science.gov (United States)

Argyraki, A.; Markvart, M.; Nielsen, Anne; Bjarnsholt, T.; Bjørndal, L.; Petersen, P. M.

2016-04-01

Disinfection routines are important in all clinical applications. The uprising problem of antibiotic resistance has driven major research efforts towards alternative disinfection approaches, involving light-based solutions. Pseudomonas aeruginosa (P. aeruginosa) is a common bacterium that can cause skin, soft tissue, lungs, kidney and urinary tract infections. Moreover, it can be found on and in medical equipment causing often cross infections in hospitals. The objective of this study was to test the efficiency, of two different light-based disinfection treatments, namely UVB and UVC irradiation, on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose was ramped from 72J/m2 to 10000J/m2. It was shown that UVB irradiation was more effective than UVC irradiation in inactivating P. aeruginosa biofilms. No colony forming units (CFU) were observed for the UVB treated biofilms when the dose was 10000 J/m2 (CFU in control sample: 7.5 x 104). UVB irradiation at a dose of 20000J/m2 on mature biofilms (72h grown) resulted in a 3.9 log killing efficacy. The fact that the wavelength of 296nm exists in daylight and has such disinfection ability on biofilms gives new perspectives for applications within disinfection at hospitals.

Efficacy of disinfectants and detergents intended for a pig farm environment where Salmonella is present.

Science.gov (United States)

Gosling, Rebecca J; Mawhinney, Ian; Vaughan, Kelly; Davies, Robert H; Smith, Richard P

2017-05-01

Disinfection is a useful component of disease control, although products and chemical groups vary in their activity against different pathogens. This study investigated the ability of fifteen disinfectants to eliminate pig-associated Salmonella. Active compounds of products included chlorocresol, glutaraldehyde/formaldehyde, glutaraldehyde/quaternary ammonium compounds (QAC), iodine, peracetic acid and potassium peroxomonosulphate. Six detergents were also tested for their ability to dislodge faecal material, and interactions with specific disinfectants. Eight serovars were screened against all products using dilution tests and a monophasic Salmonella Typhimurium strain was selected for further testing. The disinfectants were tested using models to replicate boot dip (faecal suspension) and animal housing (surface contamination) disinfection respectively at the Department for Environment, Food and Rural Affairs Approved Disinfectant General Orders (GO) concentration, half GO and twice GO. Stability over time and ability to eliminate Salmonella in biofilm was also assessed. The most effective products were then field tested. Most products at GO concentration eliminated Salmonella in the faecal suspension model. One glutaraldehyde/QAC and one glutaraldehyde/formaldehyde-based product at GO concentration eliminated Salmonella in the surface contamination model. Chlorocresol-based products were more stable in the faecal suspension model. One chlorocresol and the glutaraldehyde/formaldehyde-based product were most successful in eliminating Salmonella from biofilms. All products tested on farm reduced bacterial log counts; the glutaraldehyde/QAC based product produced the greatest reduction. The type of product and the application concentration can impact on efficacy of farm disinfection; therefore, clearer guidance is needed to ensure the appropriate programmes are used for specific environments. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

ASSESSMENT OF ACTION OF DISINFECTANTS AGAINST LISTERIA MONOCYTOGENES BIOFILMS

Directory of Open Access Journals (Sweden)

T. K. CABEÇA

2008-12-01

Full Text Available

The purpose of this study was to assess the action of various disinfectants used in food industry against biofilm cells of Listeria monocytogenes formed on stainless steel surfaces during 24, 72 and 120 hours. Numbers of viable biofilm cells decreased after treatment with all the tested disinfectants (iodine, biguanide, quaternary ammonium compounds, peracetic acid and sodium hypochlorite. Sodium hypochlorite was the most effective disinfectant against the biofilm cells, while biguanide and iodine were the least. Scanning electron microscopy observations demonstrated attached cells on stainless steel surfaces after treatment with all the disinfectants. These observations showed that microorganisms were not completely removed from stainless steel surfaces after treatment with the disinfectants, however, the attachment did not means the viability of remaining cells. The biofilm age in hours (24, 72 and 120 had no apparent influence on resistance of microbiological cells to the disinfectants under study. In conclusion biofilm cells of L. monocytogenes can withstand disinfectants action.

Studies on Disinfection By-Products and Drinking Water

Science.gov (United States)

Rostad, Colleen E.

2007-01-01

Drinking water is disinfected with chemicals to remove pathogens, such as Giardia and Cryptosproridium, and prevent waterborne diseases such as cholera and typhoid. During disinfection, by-products are formed at trace concentrations. Because some of these by-products are suspected carcinogens, drinking water utilities must maintain the effectiveness of the disinfection process while minimizing the formation of by-products.

A review on wastewater disinfection

OpenAIRE

Mohammad Mehdi Amin; Hassan Hashemi; Amir Mohammadi Bovini; Yung Tse Hung

2013-01-01

Changes in regulations and development of new technologies have affected the selection of alternative for treated wastewater disinfection. Disinfection is the last barrier of wastewater reclamation process to protect ecosystem safety and human health. Driving forces include water scarcity and drinking water supply, irrigation, rapid industrialization, using reclaimed water, source protection, overpopulation, and environmental protection. The safe operation of water reuse depends on effluent d...

OPTIMAL SCHEDULING OF BOOSTER DISINFECTION IN WATER DISTRIBUTION SYSTEMS

Science.gov (United States)

Booster disinfection is the addition of disinfectant at locations distributed throughout a water distribution system. Such a strategy can reduce the mass of disinfectant required to maintain a detectable residual at points of consumption in the distribution system, which may lea...

Sewage sludges disinfection

International Nuclear Information System (INIS)

Alexandre, D.

1977-01-01

There is an hygienic risk in using biological sewage sludges for agriculture. Systematic analysis carried out on sludges samples obtained from purification plants in East and South part of France, show the almost uniform presence of pathogenic microorganisms. Some of it survive more than 9 months after soil application. Conventional process for disinfection: liming and heat are not suitable for agricultural use. On the other hand, irradiation involves no modification in structure and composition of sludges. Radiation doses required for disinfection vary according to microorganisms. If some of them are eliminated with rather light doses (200 krad) mycobacteria, viruses and eggs of worms resist to more important doses. Security dose is estimated around 1000 krad

Portable Ultraviolet Light Surface-Disinfecting Devices for Prevention of Hospital-Acquired Infections: A Health Technology Assessment

Science.gov (United States)

Nikitovic-Jokic, Milica; Kabali, Conrad; Li, Chunmei; Higgins, Caroline

2018-01-01

Background Hospital-acquired infections (HAIs) are infections that patients contract while in the hospital that were neither present nor developing at the time of admission. In Canada an estimated 10% of adults with short-term hospitalization have HAIs. According to 2003 Canadian data, between 4% and 6% of these patients die from these infections. The most common HAIs in Ontario are caused by Clostridium difficile. The standard method of reducing and preventing these infections is decontamination of patient rooms through manual cleaning and disinfection. Several portable no-touch ultraviolet (UV) light systems have been proposed to supplement current hospital cleaning and disinfecting practices. Methods We searched for studies published from inception of UV disinfection technology to January 23, 2017. We compared portable UV surface-disinfecting devices used together with standard hospital room cleaning and disinfecting versus standard hospital cleaning and disinfecting alone. The primary outcome was HAI from C. difficile. Other outcomes were combined HAIs, colonization (i.e., carrying an infectious agent without exhibiting disease symptoms), and the HAI-associated mortality rate. We used Grading of Recommendations Assessment, Development, and Evaluation (GRADE) to rate the quality of evidence of included studies. We also performed a 5-year budget impact analysis from the hospital's perspective. This assessment was limited to portable devices and did not examine wall mounted devices, which are used in some hospitals. Results The database search for the clinical review yielded 10 peer-reviewed publications that met eligibility criteria. Three studies focused on mercury UV-C–based technology, seven on pulsed xenon UV technology. Findings were either inconsistent or produced very low-quality evidence using the GRADE rating system. The intervention was effective in reducing the rate of the composite outcome of HAIs (combined) and colonization (but quality of evidence

Disinfection by electrohydraulic treatment.

Science.gov (United States)

Allen, M; Soike, K

1967-04-28

Electrohydraulic treatment was applied to suspensions of Escherichia coli, spores of Bacillus subtilis var. niger, Saccharomyces cerevisiae, and bacteriophage T2 at an input energy that, in most cases, was below the energy required to sterilize. The input energy was held relatively constant for each of these microorganisms, but the capacitance and voltage were varied. Data are presented which show the degree of disinfection as a function of capacitance and voltage. In all cases, the degree of disinfection for a given input energy increases as both capacitance and voltage are lowered.

Chemical disinfection of combined sewer overflows

DEFF Research Database (Denmark)

Chhetri, Ravi Kumar

of the residual disinfectants PFA, PAA and chlorine dioxide (ClO2), and their degradation products hydrogen peroxide and chlorite, in relation to organisms in the aquatic ecosystem was studied. With the help of ecotoxicity data, a preliminary environmental risk assessment of PFA, PAA and ClO2 for CSO disinfection...

ANTIMICROBIAL AND STRUCTURAL EFFECTS OF DIFFERENT IRRIGATION SOLUTIONS ON GUTTA-PERCHA CONES

Directory of Open Access Journals (Sweden)

Sevinç Aktemur Türker

2015-01-01

Full Text Available Purpose: To evaluate the alterations on the surface of gutta-percha cones (GPCs on exposure to the different irrigation solutions and their possible antibacterial effect against Enterococcus faecalis. (E. faecalis Materials and Methods: Disinfection ability of different solutions (5.25% sodium hypochlorite, 2% chlorhexidine, 1% peracetic acid, and QMix were tested with 96 GPCs and the time of exposure to each solution was 5 and10 minutes, respectively. GPCs used in this study were contaminated with E.faecalis. After disinfection, GPCs were placed in tubes containing the medium and incubated at 37˚C for 7 days. All tubes were visually checked for turbidity at 24-hour intervals. About 92 new GPCs were analyzed by means of SEM/EDS to assess the topography and chemical elements present on their surface. The data generated was analyzed using Pearson chi-square test, p0.05. SEM/EDS analyses showed no alteration in the superficial features of GPCs after treating with various irrigation solutions. Conclusion: QMix was found to be an effective agent for rapid disinfection of GPCs as well-known irrigation solutions. Irrigation solutions were found to have sterilized the GPCs after both 5 and 10 minutes of exposure.

Assessment of Color Changes in Vita 3D-Master Shade Guide after Sterilization and Disinfection

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Hossein Dashti

2017-06-01

Full Text Available Purpose:Dental shade guides are commonly used for color determination and should be disinfected and sterilized. The purpose of this study was to evaluate the color change of Vita 3D Master shade tabs after disinfection and sterilization. Material and methods:Overall, 98 samples (shade tabs were randomly selected from 14 new, unused Vita 3D sets, including the following shades: 2M1, 3L1.5, 3M1, 3M2, 3M3, 3R1.5 and 4M1. In each set, values of 2, 3 and 4, chroma of 1, 2 and 3 and hue were selected for the comparison of different shades. All tabs were measured using the Vita Easyshade device at baseline. The first group was disinfected with Deconex and the second group was sterilized by autoclaving in a simulated annual application. All the tabs were measured again using the same device. This process was repeated to simulate 2 and 3 years of usage. Statistical analysis was conducted by repeated measures analysis of variance (ANOVA and independent t-test and paired sample t-test. Results:In the disinfected group, we observed significant differences in value and chroma in all periods (p˂0.001. However, hue showed no significant difference after the first year of simulated treatment (p=0.527, though it was significantly different in the second and third simulations (p˂0.001. In the sterilized group, all variables showed a significant difference for each year (p˂0.05. Considering total color difference (ΔE, there was a significant difference between the two groups in the first, second and third simulated years; ΔE increased in the sterilized group more than in the disinfected samples (p˂0.001.  Conclusions:  The color change of shade tabs was significant both after disinfection by a chemical solution and by sterilization through autoclaving. However, although disinfectants may not have a clinically important effect, sterilization should be considered as an interfering factor during color-matching procedure.

Disinfection of Biofilms in Tubes with Ultraviolet Light

DEFF Research Database (Denmark)

Bak, Jimmy; Begovic, Tanja

2009-01-01

Bacterial biofilms on long-term catheters are a major source of infection. We demonstrate here the potential of UVC light emitting diodes (LED) for disinfection purposes in catheter like tubes contaminated with biofilm. We show that UVC Light propagation is possible through teflon tubes using...... to a flow system and biofilms were produced during a three day period. Tubes in lengths of 10 cm (FEP teflon) were contaminated. Tubes for control and for UVC treatment were contaminated in parallel. The control and UVC treated tubes were both filled with a 20 % NaCl solution during the UVC treatment time...

Results from a global survey of contact lens-wearer satisfaction with OPTI-FREE® PureMoist® Multi-Purpose Disinfecting Solution

Directory of Open Access Journals (Sweden)

Lemp J

2013-11-01

Full Text Available Jessie Lemp, Jami R Kern Global Medical Affairs, Alcon Laboratories, Inc, Fort Worth, Texas, USA Purpose: The objective of the study reported here was to obtain information on acceptance and satisfaction with OPTI-FREE® PureMoist® Multi-Purpose Disinfecting Solution (MPDS from contact lens wearers globally. Methods: Eligible contact lens wearers provided baseline demographic and lens-wear-regimen information, and advised their ocular dryness/discomfort level and current lens-wear experience. Volunteers received OPTI-FREE PureMoist MPDS and a survey consisting of ten statements about the trial solution. Volunteers were instructed to use the solution daily and to complete the survey after 2 weeks of use. Descriptive statistical analysis was conducted on data from the entire group, from the subset of respondents reporting ocular dryness and/or discomfort at trial initiation (symptomatic subgroup, and from each geographic region. Results: Volunteers from nine countries returned 10,610 surveys, in which 50% of respondents classified themselves as having ocular dryness/discomfort. Lens comfort and visual performance responses from the total population and the symptomatic subgroup were significantly more positive after 2 weeks of OPTI-FREE PureMoist use than at baseline, irrespective of the habitual lens-care solution. In the USA, Southeast Asia, and Europe, 14% to 20% more respondents reported that their contact lenses provided all-day comfort after 2 weeks of OPTI-FREE PureMoist use compared with baseline (P<0.0001. Australia reported 31% more patients with all-day comfort after OPTI-FREE PureMoist use (P<0.0001. Approximately four out of five respondents from both populations reported their intent to continue using OPTI-FREE PureMoist. Globally, 39% of all respondents and 58% of symptomatic respondents experienced reduced end-of-day dryness with their contact lenses after use of OPTI-FREE PureMoist (P<0.0001. Conclusion: Results from this large

9 CFR 91.41 - Cleaning and disinfecting of aircraft.

Science.gov (United States)

2010-01-01

... of this chapter. The time at which the cleaning and disinfection is performed must be approved by the inspector, who will give approval only if he or she determines that the cleaning and disinfection will be... time, the inspector shall determine whether further cleaning and disinfection are necessary. The...

Disinfection of contaminated water by using solar irradiation.

Science.gov (United States)

Caslake, Laurie F; Connolly, Daniel J; Menon, Vilas; Duncanson, Catriona M; Rojas, Ricardo; Tavakoli, Javad

2004-02-01

Contaminated water causes an estimated 6 to 60 billion cases of gastrointestinal illness annually. The majority of these cases occur in rural areas of developing nations where the water supply remains polluted and adequate sanitation is unavailable. A portable, low-cost, and low-maintenance solar unit to disinfect unpotable water has been designed and tested. The solar disinfection unit was tested with both river water and partially processed water from two wastewater treatment plants. In less than 30 min in midday sunlight, the unit eradicated more than 4 log10 U (99.99%) of bacteria contained in highly contaminated water samples. The solar disinfection unit has been field tested by Centro Panamericano de Ingenieria Sanitaria y Ciencias del Ambiente in Lima, Peru. At moderate light intensity, the solar disinfection unit was capable of reducing the bacterial load in a controlled contaminated water sample by 4 log10 U and disinfected approximately 1 liter of water in 30 min.

Sewage sludges disinfection

International Nuclear Information System (INIS)

Alexandre, D.; Gevaudan, P.P.

1977-01-01

There is a hygienic risk in using biological sewage sludges for agriculture. Systematic analyses carried out on sludge samples obtained from purification plants in the Eastern and Southern part of France, show the almost uniform presence of pathogenic microorganisms. Some of them survive more than nine months after application to the soil. Conventional processes for disinfection, liming and heat, make the sludge unsuitable for agricultural use. On the other hand, irradiation involves no modification of structure and composition of sludges. Radiation doses required for disinfection vary according to the type of microorganism. Some of them are eliminated at rather low doses (200 krad), but mycobacteria, viruses and eggs of worms resist to more important doses. The security dose is estimated to be approx. 1000 krad

Assessing the human health impacts of exposure to disinfection by-products--a critical review of concepts and methods.

Science.gov (United States)

Grellier, James; Rushton, Lesley; Briggs, David J; Nieuwenhuijsen, Mark J

2015-05-01

Understanding the public health implications of chemical contamination of drinking water is important for societies and their decision-makers. The possible population health impacts associated with exposure to disinfection by-products (DBPs) are of particular interest due to their potential carcinogenicity and their widespread occurrence as a result of treatments employed to control waterborne infectious disease. We searched the literature for studies that have attempted quantitatively to assess population health impacts and health risks associated with exposure to DBPs in drinking water. We summarised and evaluated these assessments in terms of their objectives, methods, treatment of uncertainties, and interpretation and communication of results. In total we identified 40 studies matching our search criteria. The vast majority of studies presented estimates of generic cancer and non-cancer risks based on toxicological data and methods that were designed with regulatory, health-protective purposes in mind, and therefore presented imprecise and biased estimates of health impacts. Many studies insufficiently addressed the numerous challenges to DBP risk assessment, failing to evaluate the evidence for a causal relationship, not appropriately addressing the complex nature of DBP occurrence as a mixture of chemicals, not adequately characterising exposure in space and time, not defining specific health outcomes, not accounting for characteristics of target populations, and not balancing potential risks of DBPs against the health benefits related with drinking water disinfection. Uncertainties were often poorly explained or insufficiently accounted for, and important limitations of data and methods frequently not discussed. Grave conceptual and methodological limitations in study design, as well as erroneous use of available dose-response data, seriously impede the extent to which many of these assessments contribute to understanding the public health implications of

Silver disinfection in water distribution systems

Science.gov (United States)

Silvestry Rodriguez, Nadia

Silver was evaluated as disinfectant to maintain water quality in water distribution system. It was used to inhibit growth of two opportunistic bacteria in planktonik form and in biofilm formation in Robbins devices with stainless steel and PVC surfaces. The results of this work show that silver is a potential secondary disinfectant to be used in water distribution systems.

UV disinfection of water

International Nuclear Information System (INIS)

Skipperud, E.; Johansen; Myhrstad, J.A.

1978-01-01

UV radiation has been found to have advantages over chloration for the disinfection of water. New regulations for dietary conditions on Norwegian ships introduced in 1974 led to increased use of UV disinfection, and this has in the following years spread to waterworks. The present article is based on a study to determine possible limitation. The nature of the injuries to the microorganisms is first discussed, together with repair mechanisms. A table is given showing the energy required for 90 and 100 percent inactivation of a number of microorganisms. Some other factors affecting UV inactivation are briefly mentioned. (JIW)

Bacterial spores survive treatment with commercial sterilants and disinfectants.

Science.gov (United States)

Sagripanti, J L; Bonifacino, A

1999-09-01

This study compared the activity of commercial liquid sterilants and disinfectants on Bacillus subtilis spores deposited on three types of devices made of noncorrodible, corrodible, or polymeric material. Products like Renalin, Exspor, Wavicide-01, Cidexplus, and cupric ascorbate were tested under conditions specified for liquid sterilization. These products, at the shorter times indicated for disinfection, and popular disinfectants, like Clorox, Cavicide, and Lysol were also studied. Data obtained with a sensitive and quantitative test suggest that commercial liquid sterilants and disinfectants are less effective on contaminated surfaces than generally acknowledged.

Shift in the microbial ecology of a hospital hot water system following the introduction of an on-site monochloramine disinfection system.

Science.gov (United States)

Baron, Julianne L; Vikram, Amit; Duda, Scott; Stout, Janet E; Bibby, Kyle

2014-01-01

Drinking water distribution systems, including premise plumbing, contain a diverse microbiological community that may include opportunistic pathogens. On-site supplemental disinfection systems have been proposed as a control method for opportunistic pathogens in premise plumbing. The majority of on-site disinfection systems to date have been installed in hospitals due to the high concentration of opportunistic pathogen susceptible occupants. The installation of on-site supplemental disinfection systems in hospitals allows for evaluation of the impact of on-site disinfection systems on drinking water system microbial ecology prior to widespread application. This study evaluated the impact of supplemental monochloramine on the microbial ecology of a hospital's hot water system. Samples were taken three months and immediately prior to monochloramine treatment and monthly for the first six months of treatment, and all samples were subjected to high throughput Illumina 16S rRNA region sequencing. The microbial community composition of monochloramine treated samples was dramatically different than the baseline months. There was an immediate shift towards decreased relative abundance of Betaproteobacteria, and increased relative abundance of Firmicutes, Alphaproteobacteria, Gammaproteobacteria, Cyanobacteria and Actinobacteria. Following treatment, microbial populations grouped by sampling location rather than sampling time. Over the course of treatment the relative abundance of certain genera containing opportunistic pathogens and genera containing denitrifying bacteria increased. The results demonstrate the driving influence of supplemental disinfection on premise plumbing microbial ecology and suggest the value of further investigation into the overall effects of premise plumbing disinfection strategies on microbial ecology and not solely specific target microorganisms.

Shift in the microbial ecology of a hospital hot water system following the introduction of an on-site monochloramine disinfection system.

Directory of Open Access Journals (Sweden)

Julianne L Baron

Full Text Available Drinking water distribution systems, including premise plumbing, contain a diverse microbiological community that may include opportunistic pathogens. On-site supplemental disinfection systems have been proposed as a control method for opportunistic pathogens in premise plumbing. The majority of on-site disinfection systems to date have been installed in hospitals due to the high concentration of opportunistic pathogen susceptible occupants. The installation of on-site supplemental disinfection systems in hospitals allows for evaluation of the impact of on-site disinfection systems on drinking water system microbial ecology prior to widespread application. This study evaluated the impact of supplemental monochloramine on the microbial ecology of a hospital's hot water system. Samples were taken three months and immediately prior to monochloramine treatment and monthly for the first six months of treatment, and all samples were subjected to high throughput Illumina 16S rRNA region sequencing. The microbial community composition of monochloramine treated samples was dramatically different than the baseline months. There was an immediate shift towards decreased relative abundance of Betaproteobacteria, and increased relative abundance of Firmicutes, Alphaproteobacteria, Gammaproteobacteria, Cyanobacteria and Actinobacteria. Following treatment, microbial populations grouped by sampling location rather than sampling time. Over the course of treatment the relative abundance of certain genera containing opportunistic pathogens and genera containing denitrifying bacteria increased. The results demonstrate the driving influence of supplemental disinfection on premise plumbing microbial ecology and suggest the value of further investigation into the overall effects of premise plumbing disinfection strategies on microbial ecology and not solely specific target microorganisms.

Inactivation model for disinfection of biofilms in drinking water

International Nuclear Information System (INIS)

Karlicki, A.; O'Leary, K.C.; Gagnon, G.A.

2002-01-01

The purpose of the project was to investigate experimentally the effects of free chlorine, monochloramine and chlorine dioxide on the removal of biofilm growth in water as it applies to drinking water in distribution systems. In particular, biofilm kill for a particular dosage of disinfectant was measured as a function of time for each disinfectant over a range of disinfectant concentrations. These results were used to formulate concentration-time (Ct) inactivation values for each disinfectant to compare the efficacy of the three disinfectants for biofilm control. The biofilm reactor system consisted of a 125 mL columns, each containing tightly packed 3 mm glass beads on which heterotrophic bacterial biofilm is established. Following an initial biofilm inoculation period, the glass beads were removed from the columns and placed into glass jars for disinfection with free chlorine, monochloramine and chlorine dioxide. Cell counts were determined on a time series basis with the goal of achieving a Ct inactivation model that is similar to models presently used for inactivation of suspended cells. Ultimately this research could be used to develop a rationale method for setting regulatory values for secondary disinfection in drinking water distribution systems, which presently in only a few states and provinces. (author)

21 CFR 880.6890 - General purpose disinfectants.

Science.gov (United States)

2010-04-01

... (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use... disinfectant is a germicide intended to process noncritical medical devices and equipment surfaces. A general... prior to terminal sterilization or high level disinfection. Noncritical medical devices make only...

Ultraviolet (UV) Disinfection for Drinking Water Systems

Science.gov (United States)

UV disinfection is an effective process for inactivating many microbial pathogens in water with potential to serve as stand-alone treatment or in combination with other disinfectants. USEPA provided guidance on the validation of UV reactors nearly a decade ago. Since then, lesson...

Disinfectant effect of Methylated Ethanol against Listeria species

OpenAIRE

Y Yakubu; M D Salihu; O O Faleke; M B Abubakar; A A Magaji,A U Junaidu

2012-01-01

This study was carried out in order to determine the disinfectant effect of Methylated spirit® (95% methanol and 5% ethanol) as a teat dip against Listeria species. Hand milking was employed to collect 576 (288 x 2) raw milk samples from different lactating cows within Sokoto metropolis (Nigeria). 288 samples were collected before disinfecting the udder teats with Methylated spirit®, while the other 288 were collected after disinfection with Methylated spirit®. The ...

Radiation disinfection of sewage sludge and composting of the irradiated sludge

International Nuclear Information System (INIS)

Hashimoto, Shoji; Nishimura, Koichi; Watanabe, Hiromasa; Kawakami, Waichiro

1985-01-01

In the radiation disinfected sewage sludge, its stabilization is necessary with the composting. In this disinfected sludge, there is no need of keeping it at high temperature at the cost of fermentation velocity. The fermentation velocity can thus be set to obtain its maximum value. In sewage sludge utilization of farm land, to prevent the contamination with pathogenic bacteria and the secondary pollution, the radiation disinfection of dehydrated sludge and the composting of the disinfected sludge have been studied. The disinfection effect when an electron accelerator is used for the radiation source is described. Then, the composting of the disinfected sludge is described in chemical kinetics of the microorganisms. (Mori, K.)

A pilot solar water disinfecting system: performance analysis and testing

Energy Technology Data Exchange (ETDEWEB)

Saitoh, T.S.; El-Ghetany, H.H. [Tohoku University, Sendai (Japan). Dept. of Aeronautics and Space Engineering

2002-07-01

In most countries, contaminated water is the major cause of most water-borne diseases. Disinfection of water may be accomplished by a number of different physical-chemical treatments including direct application of thermal energy, chemical and filtration techniques. Solar energy also can be used effectively in this field because inactivation of microorganisms is done either by heating water to a disinfecting temperature or by exposing it to ultraviolet solar radiation. A pilot solar system for disinfecting contaminated water is designed, constructed and tested. Investigations are carried out to evaluate the performance of a wooden hot box solar facility as a solar disinfectant. Experimental data show that solar energy is viable for the disinfection process. A solar radiation model is presented and compared with the experimental data. A mathematical model of the solar disinfectant is also presented. The governing equations are solved numerically via the fourth-order Runge-Kutta method. The effects of environmental conditions (ambient temperature, wind speed, solar radiation, etc.) on the performance of the solar disinfectant are examined. Results showed that the system is affected by ambient temperature, wind speed, ultraviolet solar radiation intensity, the turbidity of the water, the quantity of water exposed, the contact area between the transparent water container in the solar disinfectant and the absorber plate as well as the geometrical parameters of the system. It is pointed out that for partially cloudy conditions with a low ambient temperature and high wind speeds, the thermal efficiency of the solar disinfectant is at a minimum. The use of solar energy for the disinfection process will increase the productivity of the system while completely eliminating the coliform group bacteria at the same time. (author)

Comparison of permanganate preoxidation and preozonation on algae containing water: cell integrity, characteristics, and chlorinated disinfection byproduct formation.

Science.gov (United States)

Xie, Pengchao; Ma, Jun; Fang, Jingyun; Guan, Yinghong; Yue, Siyang; Li, Xuchun; Chen, Liwei

2013-12-17

Aqueous suspensions of Microcystis aeruginosa were preoxidized with either ozone or permanganate and then subjected to chlorination under conditions simulating drinking water purification. The impacts of the two oxidants on the algal cells and on the subsequent production of dissolved organic matter and disinfection byproducts were investigated. Preozonation dramatically increased disinfection byproduct formation during chlorination, especially the formation of haloaldehydes, haloacetonitriles, and halonitromethanes. Preoxidation with permanganate had much less effect on disinfection byproduct formation. Preozonation destroyed algal cell walls and cell membranes to release intracellular organic matter (IOM), and less than 2.0% integrated cells were left after preozonation with the dosage as low as 0.4 mg/L. Preoxidation with permanganate mainly released organic matter adsorbed on the cells' surface without causing any damage to the cells' integrity, so the increase in byproduct formation was much less. More organic nitrogen and lower molecular weight precursors were produced in a dissolved phase after preozonation than permanganate preoxidation, which contributes to the significant increase of disinfection byproducts after preozonation. The results suggest that permanganate is a better choice than ozone for controlling algae derived pollutants and disinfection byproducts.

Residual viral and bacterial contamination of surfaces after cleaning and disinfection.

Science.gov (United States)

Tuladhar, Era; Hazeleger, Wilma C; Koopmans, Marion; Zwietering, Marcel H; Beumer, Rijkelt R; Duizer, Erwin

2012-11-01

Environmental surfaces contaminated with pathogens can be sources of indirect transmission, and cleaning and disinfection are common interventions focused on reducing contamination levels. We determined the efficacy of cleaning and disinfection procedures for reducing contamination by noroviruses, rotavirus, poliovirus, parechovirus, adenovirus, influenza virus, Staphylococcus aureus, and Salmonella enterica from artificially contaminated stainless steel surfaces. After a single wipe with water, liquid soap, or 250-ppm free chlorine solution, the numbers of infective viruses and bacteria were reduced by 1 log(10) for poliovirus and close to 4 log(10) for influenza virus. There was no significant difference in residual contamination levels after wiping with water, liquid soap, or 250-ppm chlorine solution. When a single wipe with liquid soap was followed by a second wipe using 250- or 1,000-ppm chlorine, an extra 1- to 3-log(10) reduction was achieved, and except for rotavirus and norovirus genogroup I, no significant additional effect of 1,000 ppm compared to 250 ppm was found. A reduced correlation between reduction in PCR units (PCRU) and reduction in infectious particles suggests that at least part of the reduction achieved in the second step is due to inactivation instead of removal alone. We used data on infectious doses and transfer efficiencies to estimate a target level to which the residual contamination should be reduced and found that a single wipe with liquid soap followed by a wipe with 250-ppm free chlorine solution was sufficient to reduce the residual contamination to below the target level for most of the pathogens tested.

Sterilization, high-level disinfection, and environmental cleaning.

Science.gov (United States)

Rutala, William A; Weber, David J

2011-03-01

Failure to perform proper disinfection and sterilization of medical devices may lead to introduction of pathogens, resulting in infection. New techniques have been developed for achieving high-level disinfection and adequate environmental cleanliness. This article examines new technologies for sterilization and high-level disinfection of critical and semicritical items, respectively, and because semicritical items carry the greatest risk of infection, the authors discuss reprocessing semicritical items such as endoscopes and automated endoscope reprocessors, endocavitary probes, prostate biopsy probes, tonometers, laryngoscopes, and infrared coagulation devices. In addition, current issues and practices associated with environmental cleaning are reviewed. Copyright © 2011. Published by Elsevier Inc.

Effect of ultrasonic pretreatment on purified water disinfection

International Nuclear Information System (INIS)

Simon Andreu, P.; Lardin Mifsut, C.; Vergara Romero, L.; Polo Canas, P. M.; Perez Sanchez, P.; Rancano Perez, A.

2009-01-01

Due to the importance of a suitable water disinfection in order to insure a pollutant effect minimization against environment, this work has been carried out to determine how can affect an ultrasonic pre-treatment upon disinfection step. It has been confirmed the ultrasonic disintegration of bacterial cells in treated water and disinfectant power of treatment by itself, which is not enough to be used as a single method in water disinfection. It has also been proved that from a technical and economical point of view the combination of UV and ultrasound improves the UV treatment performance. Finally, it has been detected that an ultrasonic pre-treatment increases chlorination effectiveness, however the high cost in this combination makes it unfeasible of industrial scale. (Author) 6 refs

Drinking water disinfection by means of ultraviolet radiation

International Nuclear Information System (INIS)

Gelzhaeuser, P.; Bewig, F.; Holm, K.; Kryschi, R.; Reich, G.; Steuer, W.

1985-01-01

The book presents all lectures held during a course at Technical Academy Esslingen, on September 10, 1985, on the subject of 'Drinking water disinfection by means of ultraviolet radiation'. The methods hitherto used for disinfection are no longer suitable because of the increasing amounts of organic pollutants found in the untreated water, and because of the necessity to make drinking water disinfection less expensive, non-polluting and thus environmentally compatible. U.V. irradiation is a method allowing technically simple and safe disinfection of the water, and also does not have any effect on the natural taste of the drinking water. The lectures presented discuss all aspects of the method, the equipment, and the performance of irradiation systems in practice. (orig./PW) [de

Fresh water disinfection by pulsed low electric field

International Nuclear Information System (INIS)

Zheng, C; Xu, Y; Liu, Z; Yan, K

2013-01-01

In this paper, we describe a pulsed low electric field process for water disinfection. Electric intensity of 0.6–1.7 kV cm −1 is applied. Experiments are performed with a 1.2 L axis-cylinder reactor. A bipolar pulsed power source with pulsed width of 25 μs and frequency of 100–3000 Hz is used. Water conductivity of 3–200 μs cm −1 is investigated, which can significantly affect pulsed voltage-current waveforms and injected energy. Energy per pulse rises with increased water conductivity. The initial E. Coli density and water conductivity are two major factors influencing the disinfection. No disinfection effect is performed with deionized water of 3 μs cm −1 . When water conductivity is 25 μs cm −1 and bacteria density is 10 4 –10 6 cfu ml −1 , significant disinfection effect is observed. More than 99% of the cells can be disinfected with an energy density of less than 70 J ml −1 , while water temperature is below 30 °C.

Adaptive Mechanisms Underlying Microbial Resistance to Disinfectants

Science.gov (United States)

2016-02-01

11775]). E.coli is a gram-negative, facultative anaerobic, and rod-shaped bacteria commonly found in warm-blooded animals . 2.1.2 Disinfectants...Nisbet, D.J. Disinfectant and Antibiotic Susceptibility Profiles of Escherichia coli O157:H7 Strains from Cattle Carcasses , Feces, and Hides and

Efficacy of Disinfection of Dental Stone Casts: Virkon versus Sodium Hypochlorite

Directory of Open Access Journals (Sweden)

Elnaz Moslehifard

2015-10-01

Full Text Available Objectives: The purpose of this experimental study was to compare the disinfection efficacy of sodium hypochlorite and peroxygenic acid (Virkon solutions for dental stone casts contaminated with microbial strains.Materials and Methods: A total of 960 spherical stone beads with a diameter of 10 mm were prepared and used as carriers of bacterial inoculums. They were individually inoculated by soaking in broth culture media containing each of the four understudy microorganisms. Different concentrations of Virkon and hypochlorite solutions were prepared using distilled water and then were sprayed on the surfaces of dental casts contaminated with Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis and Candida albicans. The pour plate technique was used to evaluate the antimicrobi- al efficacy of each solution. Microbicidal effect (ME was calculated according to the log10 of control colony counts minus the log10 of the remaining colony counts after the antimicrobial procedure. Statistical difference was assessed using the Kruskal Wallis and the Man Whitney U tests with a significance of 95%.Results: We observed different bactericidal effects of Virkon at various concentra- tions; 1% Virkon killed S. aureus, P aeruginosa, and Candida albicans, while 3% Virkon solution was required to kill B. subtilis. For S. aureus, P. aeruginosa, and C. albicans, no significant difference was observed between1% Virkon and 0.525% so- dium hypochlorite (P >0.05. For B. subtilis, the efficacy of 3% Virkon and 0.525%sodium hypochlorite was not significantly different (P >0.999.Conclusion: According to the obtained results for Virkon and based on its low toxici- ty and good environmental compatibility, it may be recommended as an antimicrobial disinfectant for dental stone casts as non-critical items.

9 CFR 53.7 - Disinfection of premises, conveyances, and materials.

Science.gov (United States)

2010-01-01

... least 7 days following such cleaning and disinfection, unless the Administrator determines that a... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of premises, conveyances... LIVESTOCK OR POULTRY § 53.7 Disinfection of premises, conveyances, and materials. All premises, including...

Application and study of conjunctival sac disinfectants in ophthalmic surgeries

Directory of Open Access Journals (Sweden)

Yan-Fei Luo

2016-01-01

Full Text Available Postoperative endophthalmitis is the most serious complications of ophthalmic surgeries. Conjunctival sac disinfection is currently recognized as an effectively important way to reduce the risk of endophthalmitis. At present, there are some disinfectants has been used in clinic or in the researches:mercury agent, gentamicin, povidone iodine and acid electrolytic water. All kinds of disinfectants play the role of disinfection by different ways. Povidone iodine is the most widely used conjunctival sac disinfectant. Mercurial and gentamicin have been rarely used because they pollute the environment, are easy to cause drug resistant bacteria, localized side reactions and so on. The acid electrolyte water is not used in clinic at present. With the popularization and development of the ophthalmic surgeries, the ophthalmologists have become more and more concerned about the postoperative eye comfort, the research and application of conjunctival sac disinfectant in the future will continue to be updated and developed.

Anaerobic effluent disinfection using ozone: Byproducts formation

NARCIS (Netherlands)

Silva, G.H.R.; Daniel, L.A.; Bruning, H.; Rulkens, W.H.

2010-01-01

This research was aimed at studying oxidation processes, coliform inactivation effectiveness and disinfection byproducts (DBPs) associated with the disinfection of anaerobic sanitary wastewater effluent with ozone applied at doses of 5.0, 8.0 and 10.0mg O(3)L(-1) for contact times of 5, 10 and 15

A 10-day vacancy period after cleaning and disinfection has no effect on the bacterial load in pig nursery units.

Science.gov (United States)

Luyckx, K; Millet, S; Van Weyenberg, S; Herman, L; Heyndrickx, M; Dewulf, J; De Reu, K

2016-10-19

Biosecurity measures such as cleaning, disinfection and a vacancy period between production cycles on pig farms are essential to prevent disease outbreaks. No studies have tested the effect of a longer vacancy period on bacterial load in nursery units. The present study evaluated the effect of a 10-day vacancy period in pig nursery units on total aerobic flora, Enterococcus spp., Escherichia coli, faecal coliforms and methicillin resistant Staphylococcus aureus (MRSA). Three vacancy periods of 10 days were monitored, each time applied in 3 units. The microbiological load was measured before disinfection and at 1, 4, 7 and 10 days after disinfection. No significant decrease or increase in E. coli, faecal coliforms, MRSA and Enterococcus spp. was noticed. Total aerobic flora counts were the lowest on day 4 after disinfection (i.e. 4.07 log CFU/625 cm 2 ) (P disinfection, drinking nipples were still mostly contaminated with total aerobic flora (i.e. 5.32 log CFU/625 cm 2 ) and Enterococcus spp. (i.e. 95 % of the samples were positive) (P disinfection with no extra biosecurity measures has no impact on the environmental load of total aerobic flora, E. coli, faecal coliforms, MRSA and Enterococcus spp..

Basic Information about Chloramines and Drinking Water Disinfection

Science.gov (United States)

Chloramines are disinfectants used to treat drinking water. Chloramines are most commonly formed when ammonia is added to chlorine to treat drinking water. Chloramines provide longer-lasting disinfection as the water moves through pipes to consumers.

40 CFR 141.709 - Developing the disinfection profile and benchmark.

Science.gov (United States)

2010-07-01

... Cryptosporidium Disinfection Profiling and Benchmarking Requirements § 141.709 Developing the disinfection profile...) of the water before or at the first customer and prior to each additional point of disinfectant...) before or at the first customer during peak hourly flow. (ii) Determine successive CTcalc/CT99.9 values...

9 CFR 51.8 - Disinfection of premises, conveyances, and materials.

Science.gov (United States)

2010-01-01

... facilities, conveyances, or other materials on the premises that would require such cleaning and disinfection... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of premises, conveyances... ANIMALS DESTROYED BECAUSE OF BRUCELLOSIS Indemnity for Cattle, Bison, and Swine § 51.8 Disinfection of...

Chemical cleaning/disinfection and ageing of organic UF membranes: a review.

Science.gov (United States)

Regula, C; Carretier, E; Wyart, Y; Gésan-Guiziou, G; Vincent, A; Boudot, D; Moulin, P

2014-06-01

Membrane separation processes have become a basic unit operation for process design and product development. These processes are used in a variety of separation and concentration steps, but in all cases, the membranes must be cleaned regularly to remove both organic and inorganic material deposited on the surface and/or into the membrane bulk. Cleaning/disinfection is a vital step in maintaining the permeability and selectivity of the membrane in order to get the plant to its original capacity, to minimize risks of bacteriological contamination, and to make acceptable products. For this purpose, a large number of chemical cleaning/disinfection agents are commercially available. In general, these cleaning/disinfection agents have to improve the membrane flux to a certain extent. However, they can also cause irreversible damages in membrane properties and performances over the long term. Until now, there is considerably less literature dedicated to membrane ageing than to cleaning/disinfection. The knowledge in cleaning/disinfection efficiency has recently been improved. But in order to develop optimized cleaning/disinfection protocols there still remains a challenge to better understand membrane ageing. In order to compensate for the lack of correlated cleaning/disinfection and ageing data from the literature, this paper investigates cleaning/disinfection efficiencies and ageing damages of organic ultrafiltration membranes. The final aim is to provide less detrimental cleaning/disinfection procedures and to propose some guidelines which should have been taken into consideration in term of membrane ageing studies. To carry out this study, this article will detail the background of cleaning/disinfection and aging membrane topics in a first introductive part. In a second part, key factors and endpoints of cleaning/disinfection and aging membranes will be discussed deeply: the membrane role and the cleaning parameters roles, such as water quality, storing conditions

Less skin irritation from alcohol-based disinfectant than from detergent used for hand disinfection

DEFF Research Database (Denmark)

Pedersen, L K; Held, E; Johansen, J D

2005-01-01

and forearms of 17 healthy volunteers. A control area was included. After 4 weeks an SLS patch was applied to each area. Irritant reactions were quantified with a visual score recording and measurements of transepidermal water loss (TEWL) and skin colour were performed on days 1, 5, 11, 38 and 40. RESULTS...... was found on the disinfectant-treated area compared with the control area and detergent area, and a similar trend was found for TEWL, although it was not statistically significant. CONCLUSION: Alcohol-based disinfectant caused less visible skin irritation and less skin barrier disruption than the use...

Disinfection for small water supplies: a technical guide

CSIR Research Space (South Africa)

Solsona, F

1990-01-01

Full Text Available This guide will present some disinfection systems, which will be useful in supporting disinfection programmes. The description of the different systems will provide a guideline for the selection of equipment base on balancing the simplicity...

Bacterial Spores Survive Treatment with Commercial Sterilants and Disinfectants

OpenAIRE

Sagripanti, Jose-Luis; Bonifacino, Aylin

1999-01-01

This study compared the activity of commercial liquid sterilants and disinfectants on Bacillus subtilis spores deposited on three types of devices made of noncorrodible, corrodible, or polymeric material. Products like Renalin, Exspor, Wavicide-01, Cidexplus, and cupric ascorbate were tested under conditions specified for liquid sterilization. These products, at the shorter times indicated for disinfection, and popular disinfectants, like Clorox, Cavicide, and Lysol were also studied. Data ob...

HIGH-RATE DISINFECTION TECHNIQUES FOR COMBIND SEWER OVERFLOW

Science.gov (United States)

This paper presents high-rate disinfection technologies for combined sewer overflow (CSO). The high-rate disinfection technologies of interest are: chlorination/dechlorination, ultraviolet light irradiation (UV), chlorine dioxide (ClO2 ), ozone (O3), peracetic acid (CH3COOOH )...

An evaluation on the antimicrobical properties of two disinfectants on dental high-speed instruments

Directory of Open Access Journals (Sweden)

Nejatidanesh F

2003-08-01

Full Text Available Statement of Problem: Rotary dental instruments (i-e. iow speed and high speed handpieces, due to"ninfection spread high potentiality, should be sterilized between dental visits for each patient. When a high"nspeed rotary instrument pauses at a high velocity, contaminated fluids like blood and saliva will be"nsucked into its tubes."nPurpose: The aim of this study was to compare the bactericidal effects ofDeconex 53 plus solution and"nthe solarsept spray on dental high- speed instruments."nMaterials and Methods: In this experimental study, one hundred and twenty (120 dental high- speed"nturbines, sterilized by autoclave, were divided into 6 groups. The turbines were contaminated with"nbacterial suspension. Streptococcus mutans, Staphilococcus aureus and Neisseria SP were the first"nmicrobial groups. Pseudomonas aruginosa was the second microbial group and Bacillus subtilis spore"nwas the third microbial group. After 5 minutes, three contaminated groups were placed in Deconex53"nplus 2% solution for 15 minutes. Three other groups after contamination were sprayed with Deconex"nsoiar sept spray for 2 minutes. Then the samples were placed in TSB culture and after 24 hours"nincubation at 37°, the samples were transmitted on blood agar solid culture for bacterial viability"nobservation. The results were observed after 24 hours incubation. Proportional test with normal"ndistribution was used for data analysis."nResults: The Deconex 53 plus had 85% disinfectant activity on the first microbial group, 10% on the"nsecond microbial group and 100% on the third microbial group. Also the solarsept spray had 30%"ndisinfectant activity on the first microbial group and 15% on the third micribial group . The solarsept"nspray had no bactericidal effect on turbines contaminated by the second microbial group. The results"nproved that the disinfectant effects of Deconex 53 plus solution for 15 minutes were significantly better"nthan the solarsept spray for 10 minutes

In-Use Evaluation of Peracetic Acid for High-Level Disinfection of Endoscopes.

Science.gov (United States)

Chenjiao, Wu; Hongyan, Zhang; Qing, Gu; Xiaoqi, Zhong; Liying, Gu; Ying, Fang

2016-01-01

Many high-level disinfectants have been used for disinfection of endoscopes such as 2% glutaraldehyde (GA), 0.55% ortho-phthalaldehyde (OPA), and peracetic acid (PAA). Both GA and OPA are widely used in disinfection of endoscopes and have been previously discussed, but there is little research on the practical use of PAA as an endoscope disinfectant. An experimental model of a flexible gastrointestinal endoscope being contaminated with 9 strains of microorganism was designed. After the cleaning and disinfecting procedure was completed, we evaluated the biocidal activity (850 ppm PAA, 2% GA, and 0.55% OPA) on our flexible gastrointestinal endoscope model. We also evaluated sterilization effectiveness of PAA on other bacteria, including some antibiotic-resistant bacteria (methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile). The residual bacterial colony count number of the PAA-disinfected endoscope was significantly lower than that of the GA- and OPA-disinfected endoscopes. The biocidal effect and efficiency of the endoscope disinfection by PAA appeared to be better than either the GA- or OPA-disinfected endoscope. PAA has demonstrated a good sterilization effect on other bacterial species; of particular note are common antibiotic-resistant bacteria such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile. The results of this study demonstrate that PAA is a fast and effective high-level disinfectant for use in the reprocessing of flexible endoscopes.

Sewage disinfection towards protection of drinking water resources.

Science.gov (United States)

Kolch, A

2000-01-01

Wastewater applied in agriculture for irrigation could replace the use of natural drinking-water resources. With respect to high concentrations of human pathogens wastewater has to be disinfected prior to use. This paper introduces disinfection methods with emphasis on UV irradiation.

Determination of several common disinfection by-products in frozen foods.

Science.gov (United States)

Cardador, Maria Jose; Gallego, Mercedes

2018-01-01

Disinfected water and/or disinfectants are commonly used by the freezing industry in such processes as sanitising, washing, blanching, cooling and transporting the final product. For this reason, disinfection by-products (DBPs) can be expected in frozen foods. This study focused on the presence of DBPs in a wide variety of frozen vegetables, meats and fish. For this purpose, the 14 halogenated DBPs more prevalent in disinfected water were selected (four trihalomethanes, seven haloacetic acids, two haloacetonitriles and trichloronitromethane). Up to seven DBPs were found in vegetables, whereas only four DBPs were present in meats and fish, and at lower concentrations, since their contact with disinfected water is lower than in frozen vegetables. It is important to emphasise that trichloronitromethane (the most abundant nitrogenous DBP in disinfected water) was found for the first time in foods. Finally, it was concluded that the freezing process can keep the compounds stable longer than other preservation processes (viz. sanitising, canning) and, therefore, frozen foods present higher DBP concentrations than other food categories (minimally processed vegetables, or canned vegetables and meats).

Development of the electrical discharge method for water disinfection

International Nuclear Information System (INIS)

Vojtenko, L.M.; Kononov, O.V.; Starchik, P.D.; Samojlenko, L.S.; Stavs'ka, S.S.

1995-01-01

Studies of processes of bacterially polluted water disinfection by the method of pulse electrical discharge in water are presented. The studies was performed to improve the disinfection technology. Main attention was concentrated to clear up effect of discharge instability on the disinfection. An influence of the shape and sizes of electrodes on repeatability of discharges was also investigated. It was found that salts solved in water greatly influence ultraviolet radiation absorption coefficients

Evaluation of an ultraviolet room disinfection protocol to decrease nursing home microbial burden, infection and hospitalization rates.

Science.gov (United States)

Kovach, Christine R; Taneli, Yavuz; Neiman, Tammy; Dyer, Elaine M; Arzaga, Alvin Jason A; Kelber, Sheryl T

2017-03-03

The focus of nursing home infection control procedures has been on decreasing transmission between healthcare workers and residents. Less evidence is available regarding whether decontamination of high-touch environmental surfaces impacts infection rates or resident outcomes. The purpose of this study was to examine if ultraviolet disinfection is associated with changes in: 1) microbial counts and adenosine triphosphate counts on high-touch surfaces; and 2) facility wide nursing home acquired infection rates, and infection-related hospitalization. The study was conducted in one 160-bed long-term care facility. Following discharge of each resident, their room was cleaned and then disinfected using a newly acquired ultraviolet light disinfection device. Shared living spaces received weekly ultraviolet light disinfection. Thirty-six months of pretest infection and hospitalization data were compared with 12 months of posttest data. Pre and posttest cultures were taken from high-touch surfaces, and luminometer readings of adenosine triphosphate were done. Nursing home acquired infection rates were analyzed relative to hospital acquired infection rates using analysis of variance procedures. Wilcoxon signed rank tests, The Cochran's Q, and Chi Square were also used. There were statistically significant decreases in adenosine triphosphate readings on all high-touch surfaces after cleaning and disinfection. Culture results were positive for gram-positive cocci or rods on 33% (n = 30) of the 90 surfaces swabbed at baseline. After disinfectant cleaning, 6 of 90 samples (7.1%) tested positive for a gram-positive bacilli, and after ultraviolet disinfection 4 of the 90 samples (4.4%) were positive. There were significant decreases in nursing home acquired relative to hospital-acquired infection rates for the total infections (p = .004), urinary tract infection rates (p = .014), respiratory system infection rates (p = .017) and for rates of infection of the skin

Effect of alginate chemical disinfection on bacterial count over gypsum cast

OpenAIRE

Haralur, Satheesh B.; Al-Dowah, Omir S.; Gana, Naif S.; Al-Hytham, Abdullah

2012-01-01

PURPOSE To evaluate the efficacy of sodium hypochlorite (1 : 10) and iodophor disinfectants on alginate impressions along with their effect on the survived bacterium count on the gypsum cast. MATERIALS AND METHODS Four alginate impression on each dentate patients were made, of which Group I were not washed or disinfected, Group II impressions were merely washed with water, Group III were disinfected by spraying with sodium hypochlorite (1 : 10), Group IV were disinfected with iodophor (1 : 21...

Intracellular mechanisms of solar water disinfection

Science.gov (United States)

Castro-Alférez, María; Polo-López, María Inmaculada; Fernández-Ibáñez, Pilar

2016-12-01

Solar water disinfection (SODIS) is a zero-cost intervention measure to disinfect drinking water in areas of poor access to improved water sources, used by more than 6 million people in the world. The bactericidal action of solar radiation in water has been widely proven, nevertheless the causes for this remain still unclear. Scientific literature points out that generation of reactive oxygen species (ROS) inside microorganisms promoted by solar light absorption is the main reason. For the first time, this work reports on the experimental measurement of accumulated intracellular ROS in E. coli during solar irradiation. For this experimental achievement, a modified protocol based on the fluorescent probe dichlorodihydrofluorescein diacetate (DCFH-DA), widely used for oxidative stress in eukaryotic cells, has been tested and validated for E. coli. Our results demonstrate that ROS and their accumulated oxidative damages at intracellular level are key in solar water disinfection.

Role of disinfection in the Infection Prevention Multibarrier System

OpenAIRE

Kramer, Axel

2007-01-01

The role of disinfection in infection prevention has been analyzed over the past 50 years both in the form of benefit-risk evaluations as well as in an epidemiological sense. This has served as the basis for not only national and international guidelines and recommendations, but has also created the legal and normative framework for regulation of infection control (and hence of disinfection) in numerous and acts and ordinances. Likewise, today the efficacy of disinfection measures, user safet...

Efficacy of a variety of disinfectants against Listeria spp.

OpenAIRE

Best, M; Kennedy, M E; Coates, F

1990-01-01

The efficacy of 14 disinfectants against Listeria innocua and two strains of Listeria monocytogenes in the presence of organic matter was studied. Quantitative efficacy tests were used. Many of the disinfectants tested were not as effective on Listeria spp. when the test organisms were dried onto the surface of steel disks (carrier tests) as they were when the organisms were placed in suspension (suspension test). The presence of whole serum and milk (2% fat) further reduced the disinfectant ...

Peracetic acid (PAA) disinfection of primary, secondary and tertiary treated municipal wastewaters.

Science.gov (United States)

Koivunen, J; Heinonen-Tanski, H

2005-11-01

The efficiency of peracetic acid (PAA) disinfection against enteric bacteria and viruses in municipal wastewaters was studied in pilot-scale. Disinfection pilot-plant was fed with the primary or secondary effluent of Kuopio municipal wastewater treatment plant or tertiary effluent from the pilot-scale dissolved air flotation (DAF) unit. Disinfectant doses ranged from 2 to 7 mg/l PAA in the secondary and tertiary effluents, and from 5 to 15 mg/l PAA in the primary effluents. Disinfection contact times were 4-27 min. Disinfection of secondary and tertiary effluents with 2-7 mg/l PAA and 27 min contact time achieved around 3 log reductions of total coliforms (TC) and enterococci (EC). PAA disinfection also significantly improved the hygienic quality of the primary effluents: 10-15 mg/l PAA achieved 3-4 log reductions of TC and EC, 5 mg/l PAA resulting in below 2 log reductions. F-RNA coliphages were more resistant against the PAA disinfection and around 1 log reductions of these enteric viruses were typically achieved in the disinfection treatments of the primary, secondary and tertiary effluents. Most of the microbial reductions occurred during the first 4-18 min of contact time, depending on the PAA dose and microorganism. The PAA disinfection efficiency remained relatively constant in the secondary and tertiary effluents, despite of small changes of wastewater quality (COD, SS, turbidity, 253.7 nm transmittance) or temperature. The disinfection efficiency clearly decreased in the primary effluents with substantially higher microbial, organic matter and suspended solids concentrations. The results demonstrated that PAA could be a good alternative disinfection method for elimination of enteric microbes from different wastewaters.

Conservative treatment of immature teeth with apical periodontitis using triple antibiotic paste disinfection

OpenAIRE

Wang, Hsin-Ju; Chen, Yea-Huey Melody; Chen, Kuan-Liang

2016-01-01

The purpose of this report is to present conservative treatment for two immature premolars with apical periodontitis. A triple antibiotic paste was used to disinfect the root canal systems for revascularization. In both cases, residual vital pulp tissue was noted in the root canal system after the opening of each premolar. The canals in both cases were irrigated with copious sodium hypochlorite solution and medicated with a paste consisting of ciprofloxacin, metronidazole, and minocycline. Th...

Validated measurements of microbial loads on environmental surfaces in intensive care units before and after disinfecting cleaning.

Science.gov (United States)

Frickmann, H; Bachert, S; Warnke, P; Podbielski, A

2018-03-01

Preanalytic aspects can make results of hygiene studies difficult to compare. Efficacy of surface disinfection was assessed with an evaluated swabbing procedure. A validated microbial screening of surfaces was performed in the patients' environment and from hands of healthcare workers on two intensive care units (ICUs) prior to and after a standardized disinfection procedure. From a pure culture, the recovery rate of the swabs for Staphylococcus aureus was 35%-64% and dropped to 0%-22% from a mixed culture with 10-times more Staphylococcus epidermidis than S. aureus. Microbial surface loads 30 min before and after the cleaning procedures were indistinguishable. The quality-ensured screening procedure proved that adequate hygiene procedures are associated with a low overall colonization of surfaces and skin of healthcare workers. Unchanged microbial loads before and after surface disinfection demonstrated the low additional impact of this procedure in the endemic situation when the pathogen load prior to surface disinfection is already low. Based on a validated screening system ensuring the interpretability and reliability of the results, the study confirms the efficiency of combined hand and surface hygiene procedures to guarantee low rates of bacterial colonization. © 2017 The Society for Applied Microbiology.

In situ disinfection of sewage contaminated shallow groundwater: a feasibility study.

Science.gov (United States)

Bailey, Morgan M; Cooper, William J; Grant, Stanley B

2011-11-01

Sewage-contaminated shallow groundwater is a potential cause of beach closures and water quality impairment in marine coastal communities. In this study we set out to evaluate the feasibility of several strategies for disinfecting sewage-contaminated shallow groundwater before it reaches the coastline. The disinfection rates of Escherichia coli (EC) and enterococci bacteria (ENT) were measured in mixtures of raw sewage and brackish shallow groundwater collected from a coastal community in southern California. Different disinfection strategies were explored, ranging from benign (aeration alone, and aeration with addition of brine) to aggressive (chemical disinfectants peracetic acid (PAA) or peroxymonosulfate (Oxone)). Aeration alone and aeration with brine did not significantly reduce the concentration of EC and ENT after 6 h of exposure, while 4-5 mg L(-1) of PAA or Oxone achieved >3 log reduction after 15 min of exposure. Oxone disinfection was more rapid at higher salinities, most likely due to the formation of secondary oxidants (e.g., bromine and chlorine) that make this disinfectant inappropriate for marine applications. Using a Lagrangian modeling framework, we identify several factors that could influence the performance of in-situ disinfection with PAA, including the potential for bacterial regrowth, and the non-linear dependence of disinfection rate upon the residence time of water in the shallow groundwater. The data and analysis presented in this paper provide a framework for evaluating the feasibility of in-situ disinfection of shallow groundwater, and elucidate several topics that warrant further investigation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Mechanical and Morphological Effect of Plant Based Antimicrobial Solutions on Maxillofacial Silicone Elastomer.

Science.gov (United States)

Tetteh, Sophia; Bibb, Richard J; Martin, Simon J

2018-05-30

The objective of this study was to determine the effect of plant based antimicrobial solutions specifically tea tree and Manuka oil on facial silicone elastomers. The purpose of this in vitro study was to evaluate the effect of disinfection with plant extract solution on mechanical properties and morphology on the silicone elastomer. Test specimens were subjected to disinfection using tea tree oil, Manuka oil and the staphylococcus epidermidis bacteria. Furthermore, a procedure duration was used in the disinfection process to simulate up to one year of usage. Over 500 test specimens were fabricated for all tests performed namely hardness, elongation, tensile, tear strength tests, visual inspection and lastly surface characterization using SEM. A repeated measures ANOVA revealed that hardness and elongation at break varied significantly over the time period, whereas this was not observed in the tear and tensile strength parameters of the test samples.

Mechanical and Morphological Effect of Plant Based Antimicrobial Solutions on Maxillofacial Silicone Elastomer

Directory of Open Access Journals (Sweden)

Sophia Tetteh

2018-05-01

Full Text Available The objective of this study was to determine the effect of plant based antimicrobial solutions specifically tea tree and Manuka oil on facial silicone elastomers. The purpose of this in vitro study was to evaluate the effect of disinfection with plant extract solution on mechanical properties and morphology on the silicone elastomer. Test specimens were subjected to disinfection using tea tree oil, Manuka oil and the staphylococcus epidermidis bacteria. Furthermore, a procedure duration was used in the disinfection process to simulate up to one year of usage. Over 500 test specimens were fabricated for all tests performed namely hardness, elongation, tensile, tear strength tests, visual inspection and lastly surface characterization using SEM. A repeated measures ANOVA revealed that hardness and elongation at break varied significantly over the time period, whereas this was not observed in the tear and tensile strength parameters of the test samples.

Selection criteria for water disinfection techniques in agricultural practices.

Science.gov (United States)

Haute, Sam van; Sampers, Imca; Jacxsens, Liesbeth; Uyttendaele, Mieke

2015-01-01

This paper comprises a selection tool for water disinfection methods for fresh produce pre- and postharvest practices. A variety of water disinfection technologies is available on the market and no single technology is the best choice for all applications. It can be difficult for end users to choose the technology that is best fit for a specific application. Therefore, the different technologies were characterized in order to identify criteria that influence the suitability of a technology for pre- or postharvest applications. Introduced criteria were divided into three principal components: (i) criteria related to the technology and which relate to the disinfection efficiency, (ii) attention points for the management and proper operation, and (iii) necessities in order to sustain the operation with respect to the environment. The selection criteria may help the end user of the water disinfection technology to obtain a systematic insight into all relevant aspects to be considered for preliminary decision making on which technologies should be put to feasibility testing for water disinfection in pre- and postharvest practices of the fresh produce chain.

Disinfection of drinking water

Energy Technology Data Exchange (ETDEWEB)

Ensenauer, P

1977-01-01

Some methods for disinfecting drinking water are described, e.g. UV irradiation (optimal wavelength 210-250mm) with the advantage of constant water composition and the resulting danger of re-infection.

Does disinfection of environmental surfaces influence nosocomial infection rates? A systematic review.

Science.gov (United States)

Dettenkofer, Markus; Wenzler, Sibylle; Amthor, Susanne; Antes, Gerd; Motschall, Edith; Daschner, Franz D

2004-04-01

To review the evidence on the effects of disinfection of environmental surfaces in hospitals (as compared with cleaning without use of disinfectants) on the occurrence of nosocomial infections. Systematic review of experimental and nonexperimental intervention studies dealing with environmental disinfection or cleaning in different health care settings. A total of 236 scientific articles were identified. None described a meta-analysis, systematic review, or randomized controlled trial. Only 4 articles described completed cohort studies matching the inclusion criteria. None of these studies showed lower infection rates associated with routine disinfection of surfaces (mainly floors) versus cleaning with detergent only. Disinfectants may pose a danger to staff, patients, and the environment and require special safety precautions. However, targeted disinfection of certain environmental surfaces is in certain instances an established component of hospital infection control. Given the complex, multifactorial nature of nosocomial infections, well-designed studies that systematically investigate the role of surface disinfection are required.

[Efficacy of disinfection treatments using essential oils and ultrasound on tomato fruits inoculated with Escherichia coli and impact on antioxidant activity].

Science.gov (United States)

Luna Guevara, María L; Luna Guevara, Juan J; Ruiz Espinosa, Héctor; Leyva Abascal, Lucero; Díaz González, Carolina B

2015-01-01

Fresh produce often harbors a great number of microorganisms; hence, its growing demand may constitute a risk for consumers. The aim of this study was to evaluate the efficacy of several disinfection procedures against enterotoxigenic Escherichia coli (ETEC) inoculated on tomato fruits and the conservation of the antioxidant properties of these disinfected fruits. Fruits were immersed for 5 or 10min in oregano or thyme essential oil dispersions (5, 10ppm), with or without ultrasound treatment. Antioxidant activity of disinfected fruits was determined as the ability to scavenge 2,2-diphenyl-1-pricrylhydrazyl (DPPH) radicals and was reported as percentage of inhibition (%I). The most efficient disinfectant treatments showing significant differences (p≤.05) between the reductions log10 CFU/g (S) of ETEC were those using 10ppm oregano for 10min, with S=3.05 in individual treatments and S=4.03 in mixed treatments. The highest %I was obtained with individual sonication treatments (69.52 and 72.48), while in combined treatments the %I values increased with thyme oil 5ppm and ultrasound for 5min (51.27%) and 10min (53.31%). Copyright © 2015 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Inactivation of influenza A virus H1N1 by disinfection process.

Science.gov (United States)

Jeong, Eun Kyo; Bae, Jung Eun; Kim, In Seop

2010-06-01

Because any patient, health care worker, or visitor is capable of transmitting influenza to susceptible persons within hospitals, hospital-acquired influenza has been a clinical concern. Disinfection and cleaning of medical equipment, surgical instruments, and hospital environment are important measures to prevent transmission of influenza virus from hospitals to individuals. This study was conducted to evaluate the efficacy of disinfection processes, which can be easily operated at hospitals, in inactivating influenza A virus H1N1 (H1N1). The effects of 0.1 mol/L NaOH, 70% ethanol, 70% 1-propanol, solvent/detergent (S/D) using 0.3% tri (n-butyl)-phosphate and 1.0% Triton X-100, heat, and ethylene oxide (EO) treatments in inactivating H1N1 were determined. Inactivation of H1N1 was kinetically determined by the treatment of disinfectants to virus solution. Also, a surface test method, which involved drying an amount of virus on a surface and then applying the inactivation methods for 1 minute of contact time, was used to determine the virucidal activity. H1N1 was completely inactivated to undetectable levels in 1 minute of 70% ethanol, 70% 1-propanol, and solvent/detergent treatments in the surface tests as well as in the suspension tests. H1N1 was completely inactivated in 1 minute of 0.1 mol/L NaOH treatment in the suspension tests and also effectively inactivated in the surface tests with the log reduction factor of 3.7. H1N1 was inactivated to undetectable levels within 5 minutes, 2.5 minutes, and 1 minute of heat treatment at 70, 80, and 90 degrees C, respectively in the suspension tests. Also, H1N1 was completely inactivated by EO treatment in the surface tests. Common disinfectants, heat, and EO tested in this study were effective at inactivating H1N1. These results would be helpful in implementing effective disinfecting measures to prevent hospital-acquired infections. Copyright 2010 Association for Professionals in Infection Control and Epidemiology, Inc

Chemical surface disinfection of eggs of Baltic cod, Gadus morhua L

DEFF Research Database (Denmark)

Overton, J L; Bruun, Morten Sichlau; Dalsgaard, Inger

2010-01-01

The effect of two disinfectants on eggs and larvae of Baltic cod, Gadus morhua, was investigated. The eggs were disinfected for 10 min using various concentrations of either glutaraldehyde (100, 200, 400, 600 and 800 mg L−1) or iodophor (10, 50, 100 and 150 mg L−1), 1–4-days post......-fertilization. Bactericidal effect of disinfection, survival to hatching, hatching success and larval abnormalities were assessed. Larval survival was recorded at 5-, 10- and 15-days post-hatch (dph). Although Baltic cod eggs have an unusually thin chorion, they could tolerate surface disinfection. A reduction in bacterial...... growth was observed with increased concentrations of disinfectant (3.0 × 107–1.6 × 101 CFU mL−1). Abnormalities in newly hatched larvae were not related to disinfection. Survival of the yolk sac larvae was significantly better for eggs treated with 400 mg L−1 glutaraldehyde for 10 min at 10 and 15 dph...

A Review of Heterogeneous Photocatalysis for Water and Surface Disinfection

Directory of Open Access Journals (Sweden)

John Anthony Byrne

2015-03-01

Full Text Available Photo-excitation of certain semiconductors can lead to the production of reactive oxygen species that can inactivate microorganisms. The mechanisms involved are reviewed, along with two important applications. The first is the use of photocatalysis to enhance the solar disinfection of water. It is estimated that 750 million people do not have accessed to an improved source for drinking and many more rely on sources that are not safe. If one can utilize photocatalysis to enhance the solar disinfection of water and provide an inexpensive, simple method of water disinfection, then it could help reduce the risk of waterborne disease. The second application is the use of photocatalytic coatings to combat healthcare associated infections. Two challenges are considered, i.e., the use of photocatalytic coatings to give “self-disinfecting” surfaces to reduce the risk of transmission of infection via environmental surfaces, and the use of photocatalytic coatings for the decontamination and disinfection of medical devices. In the final section, the development of novel photocatalytic materials for use in disinfection applications is reviewed, taking account of materials, developed for other photocatalytic applications, but which may be transferable for disinfection purposes.

Modern technologies for improving cleaning and disinfection of environmental surfaces in hospitals.

Science.gov (United States)

Boyce, John M

2016-01-01

Experts agree that careful cleaning and disinfection of environmental surfaces are essential elements of effective infection prevention programs. However, traditional manual cleaning and disinfection practices in hospitals are often suboptimal. This is often due in part to a variety of personnel issues that many Environmental Services departments encounter. Failure to follow manufacturer's recommendations for disinfectant use and lack of antimicrobial activity of some disinfectants against healthcare-associated pathogens may also affect the efficacy of disinfection practices. Improved hydrogen peroxide-based liquid surface disinfectants and a combination product containing peracetic acid and hydrogen peroxide are effective alternatives to disinfectants currently in widespread use, and electrolyzed water (hypochlorous acid) and cold atmospheric pressure plasma show potential for use in hospitals. Creating "self-disinfecting" surfaces by coating medical equipment with metals such as copper or silver, or applying liquid compounds that have persistent antimicrobial activity surfaces are additional strategies that require further investigation. Newer "no-touch" (automated) decontamination technologies include aerosol and vaporized hydrogen peroxide, mobile devices that emit continuous ultraviolet (UV-C) light, a pulsed-xenon UV light system, and use of high-intensity narrow-spectrum (405 nm) light. These "no-touch" technologies have been shown to reduce bacterial contamination of surfaces. A micro-condensation hydrogen peroxide system has been associated in multiple studies with reductions in healthcare-associated colonization or infection, while there is more limited evidence of infection reduction by the pulsed-xenon system. A recently completed prospective, randomized controlled trial of continuous UV-C light should help determine the extent to which this technology can reduce healthcare-associated colonization and infections. In conclusion, continued efforts to

[Experiments on disinfection of vaccinia virus embedded in scabs and/or at the hand].

Science.gov (United States)

Schümann, K; Grossgebauer, K

1977-01-01

Vaccinia viruses embedded in rabbit dermal scabs were subjected to physical and chemical disinfection procedures. Scabs were suspended in vitro without saline or in physiological saline, and left for 1 hour at 70 to 90 degrees C. A complete inactivation was achived only in those scab samples which had been incubated at 90 degrees C for 1 hour and suspended in physiological saline. Scabs which had been placed in a disinfecting apparatus (Vacudes 4000) filled with mattrasses consistently proved to be free of infectious vaccinia viruses in each of the chosen programs. In addition scabs were subjected to disinfection by means of chemical disinfecting agents. The scabs had been placed in a chemical disinfecting suspension and left there for 90 minutes. Complete disinfection was obtained with glutaraldehyde 2%, formaldehyde 2%, Lysoformin 2% or 3%, phenol 5% and chloramine T 2%. Complete disinfection was likewise achieved after 3 hours treatment with some alchohols (ethylalcohol 80%, isopropylalcohol 7%, n-propylalcohol 60%), Amocid 5% and formaldehyde 1%.0.5% formaldehyde caused complete disinfection when applied for 6 hours. The only exception was a Quat which did not disinfect fully even after 18 hours application. Concerning the tests to disinfect the hands complete disinfection occurs when using chloramine T (1.5%) or isopropylalcohol (70%) in 2 to 5 minutes. Further tests were performed with scabs which were placed in sick rooms that were terminally disinfected with formaline vapor. It could be confirmed that the usual terminal disinfection with formaldehyde vapor was unable to completely disinfect the scabs. It is necessary to double the amount of formaldehyde (10 g formaldehyde per cubic metre of space) and prolong the period of treatment to 24 hours to achieve a greater degree of disinfection rate.

Evaluation of the efficiency of the photo Fenton disinfection of natural drinking water source during the rainy season in the Sahelian region.

Science.gov (United States)

Ndounla, J; Pulgarin, C

2014-09-15

The photo-disinfection of water from two different wells (W1, pH: 4.6-5.1 ± 0.02) and (W2 pH: 5.6-5.7 ± 0.02) was carried out during the rainy season at Ouagadougou-Burkina Faso, West Africa. The weather variation during the rainy season significantly affects the photo-disinfection processes (solar disinfection and photo-Fenton). The dilution of the water by rainwater highly affected the chemical composition of the wells' water used in this study; very low iron contents Compared to the ones recorded during the dry season were recorded in all water samples. Both photo-disinfection processes were used to treat 25 L of water in a compound parabolic collector (CPC). None of them have shown the total inactivation of both wild enteric bacteria strains (total coliforms/E. coli and Salmonella spp.) involved in the treatment. However, the total coliforms/E. coli strains were totally inactivated during the exposure under most of the photo-Fenton treatment. Also, the remaining strains, especially those of Salmonella spp. were achieved during the subsequent 24h of dark storage under the action of the Fenton process. Under uniquely solar radiation, total inactivation was recorded only in the total coliforms/E. coli strains. The impact of the available irradiance on the efficiency of the photo-Fenton disinfection of natural water was highlighted during the exposure under high intermittent solar radiation. The impact of the HCO3(-) concentration of both wells' water on the evolution of the pH during the photo-disinfection was recorded. Drastic decrease was noticed after the initial fast increase in presence of low HCO3(-) concentration while a steady state was observed after the increase in presence of higher concentration. The redox activities of the nitrogen components of the water during both photo-disinfection processes have led to increased concentration of nitrite in all the cases and variations were noticed in that of nitrate and ammonia. Copyright © 2014 Elsevier B

Disinfecting the iPad: evaluating effective methods.

Science.gov (United States)

Howell, V; Thoppil, A; Mariyaselvam, M; Jones, R; Young, H; Sharma, S; Blunt, M; Young, P

2014-06-01

Tablet computers are increasingly used in healthcare, but they may carry nosocomial pathogens. There are few data available on how to clean an iPad effectively for use in the clinical setting. We aimed to identify the most effective method of decontaminating the Apple iPad, without causing damage, and establish the duration of any residual effect. Following contamination with a microbial broth (meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococcus (VRE) and Clostridium difficile), we examined efficacy of iPad disinfection in the laboratory using six different disinfectant wipes: Sani-Cloth CHG 2% (chlorhexidine 2%/alcohol 70%), Clorox, Tristel, Trigene, soap and water, and plain cloth. Following cleaning, iPads were recontaminated to examine residual activity. After 480 Sani-Cloth CHG 2% disinfecting episodes, functional and visual analysis of iPads was performed by blinded subjects. With the exception of Clostridium difficile, Sani-Cloth CHG 2% and Clorox wipes were most effective against MRSA and VRE, and they were significantly better than the Apple-recommended plain cloth (P ≤ 0.001). A substantial residual antimicrobial effect was seen for >6h after wiping the iPad with Sani-Cloth CHG 2% despite repeated recontamination and without further disinfection. The functionality or visual appearance of the iPad was not damaged by repeated use of Sani-Cloth CHG 2% wipes. Sani-Cloth CHG 2% wipes effectively disinfect the iPad against MRSA and VRE, with a residual antibacterial effect and without causing damage. Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Disinfection of drinking water

International Nuclear Information System (INIS)

Ensenauer, P.

1977-01-01

Some methods for disinfecting drinking water are described, e.g. UV irradiation (optimal wavelength 210-250mm) with the advantage of constant water composition and the resulting danger of re-infection. (AJ) [de

Composting of gamma-radiation disinfected sewage sludge

International Nuclear Information System (INIS)

Kawakami, W.; Hashimoto, S.; Watanabe, H.; Nishimura, K.; Watanabe, H.; Ito, H.; Takehisa, M.

1981-01-01

The composting of radiation disinfected sewage sludge has been studied since 1978, aiming to present a new process of sludge composting for agricultural uses. This process is composed of two steps: irradiation step to disinfect sludge, and composting step to remove odor and easily decomposable organics in sludge. In this paper, the gamma-irradiation effect on sludge cake and composting condition of irradiated sludge are discussed. (author)

Technical considerations during disinfection by UV

International Nuclear Information System (INIS)

Ekhtiarzadeh, Z.; Sadeghpur, H.

2002-01-01

The use of new methods for treatment of water and wastewater in the country is one the rise and therefore the theoretical and practical knowledge of the industry's engineers should increase simultaneously. Ultraviolet is one of the new technologies used both for treatment of water as well as wastewater. The UV disinfection system consists of different components such as the lamp, ballast and the lamp fixtures. Each has a specification, which should be taken into account prior to design, order and purchase. The subject of price is also among the important considerations. The article presents figures cost comparison in various sections. It does not try to either approve or reject other disinfection systems such as chlorination, but the writer believes that any method should find its own practice and conditions of use, and the disinfection system designers should opt for the best system suited to their plans and avoid limiting themselves to a single one

Association of high-level humidifier disinfectant exposure with lung injury in preschool children.

Science.gov (United States)

Park, Dong-Uk; Ryu, Seung-Hun; Roh, Hyun-Suk; Lee, Eun; Cho, Hyun-Ju; Yoon, Jisun; Lee, So-Yeon; Cho, Young Ah; Do, Kyung-Hyun; Hong, Soo-Jong

2018-03-01

Children aged ≤6years reportedly account for 52% of victims of humidifier disinfectant-associated lung injuries. To evaluate the association of humidifier disinfectants with lung injury risk among children aged ≤6years. Patients with humidifier disinfectant-associated lung injuries (n=214) who were clinically evaluated to have a definite (n=108), probable (n=49), or possible (n=57) association with humidifier disinfectants as well as control patients (n=123) with lung injury deemed unlikely to be associated with humidifier disinfectant use were evaluated to determine factors associated with increased risk of humidifier disinfectant-associated lung injury using unconditional multiple logistic regression analysis. For estimated airborne humidifier disinfectant concentrations, risk of humidifier disinfectant-associated lung injury increased ≥two-fold in a dose-dependent manner in the highest quartile (Q4, 135-1443μg/m 3 ) compared with that in the lowest quartile (Q1, ≤33μg/m 3 ). Registered patients using more than two humidifier disinfectant brands were at an increased risk of humidifier disinfectant-associated lung injury (adjusted OR, 2.2; 95% confidence interval, 1.3-3.8) compared with those using only one brand. With respect to the duration of humidifier disinfectant use, risk of humidifier disinfectant-associated lung injury increased ≥two-fold in the lowest quartile (≤5months) compared with that in the highest quartile (≥14months; adjusted OR 0.3; 95% confidence interval, 0.2-0.6). Younger children are more vulnerable to HDLI when exposed to HD chemicals within short period in early life. Copyright © 2017 Elsevier B.V. All rights reserved.

Disinfection of bore well water with chlorine dioxide/sodium hypochlorite and hydrodynamic cavitation.

Science.gov (United States)

Wang, Yifei; Jia, Aiyin; Wu, Yue; Wu, Chunde; Chen, Lijun

2015-01-01

The effect of hydrodynamic cavitation (HC) on potable water disinfection of chemicals was investigated. The bore well water was introduced into HC set-up to examine the effect of HC alone and combination of HC and chemicals such as chlorine dioxide and sodium hypochlorite. The effect of inlet pressure and geometrical parameters on disinfection was studied using HC alone and the results showed that increasing inlet pressure and using more and bigger holes of orifice plates can result in a higher disinfection rates. When HC was combined with chemicals, HC can reduce the doses of the chemicals and shorten the time of disinfection. It was also found that the decrease in bacteria concentration followed a first-order kinetic model. As for the experiment of combination of HC and sodium hypochlorite for disinfection, HC not only improves the disinfection rate but also degrades natural organic matter and chloroform. Compared with only sodium hypochlorite disinfection, combined processes get higher disinfection rate and lower production of chloroform, particularly the pretreatment with HC enhances the disinfection rate by 32% and there is a simultaneous reduction in production of chloroform by 39%.

Drinking Water Supply without Use of a Disinfectant

Science.gov (United States)

Rajnochova, Marketa; Tuhovcak, Ladislav; Rucka, Jan

2018-02-01

The paper focuses on the issue of drinking water supply without use of any disinfectants. Before the public water supply network operator begins to consider switching to operation without use of chemical disinfection, initial assessment should be made, whether or not the water supply system in question is suitable for this type of operation. The assessment is performed by applying the decision algorithm. The initial assessment is followed by another decision algorithm which serves for managing and controlling the process of switching to drinking water supply without use of a disinfectant. The paper also summarizes previous experience and knowledge of this way operated public water supply systems in the Czech Republic.

The effect of prolonged storage and disinfection on the dimensional stability of 5 vinyl polyether silicone impression materials.

Science.gov (United States)

Nassar, Usama; Flores-Mir, Carlos; Heo, Giseon; Torrealba, Ysidora

2017-06-01

Vinyl polyether silicone (VPES) has a different composition from other elastomeric impression materials as it combines vinyl polysiloxane (VPS) and polyether (PE). Therefore, it is important to study its properties and behavior under different test conditions. This study investigated the dimensional stability of 5 VPES consistencies when stored for up to 2 weeks, with and without using a standard disinfection procedure. 40 discs of each VPES consistency (total 200) were made using a stainless steel die and ring as described by ANSI /ADA specification No. 19. 20 discs of each material were immersed in a 2.5% buffered glutaraldehyde solution for 30 minutes. Dimensional stability measurements were calculated immediately after fabrication and repeated on the same discs after 7 and 14 days of storage. The data was analyzed using two-way ANOVA with a significance level set at α = 0.05. The discs mean contraction was below 0.5% at all test times ranging from 0.200 ± 0.014 to 0.325 ± 0.007. Repeated measures ANOVA showed a statistically significant difference after 2-week storage between the disinfected and non-disinfected groups ( P < .001). Although there was no statistically significant difference between the materials at the time of fabrication, the contraction of the materials increased with storage for 1 and 2 weeks. The dimensional changes of VPES impression discs after disinfection and prolonged storage complied with ANSI/ADA standard. The tested VPES impression materials were dimensionally stable for clinical use after disinfection for 30 minutes in glutaraldehyde and storage for up to 2 weeks.

Evaluation of the efficiency of the photo Fenton disinfection of natural drinking water source during the rainy season in the Sahelian region

Energy Technology Data Exchange (ETDEWEB)

Ndounla, J., E-mail: juliette.ndounla@epfl.ch [Ecole Polytechnique Fédérale de Lausanne, Institute of Chemical Sciences and Engineering GPAO, Station 6, CH 1015 Lausanne (Switzerland); Institut International d' Ingénierie de l' Eau et de l' Environnement, Laboratoire Eau, Dépollution, Ecosystème et Santé (LEDES), 01 BP 594 Ouagadougou 01 (Burkina Faso); Pulgarin, C., E-mail: Cesar.pulgarin@epfl.ch [Ecole Polytechnique Fédérale de Lausanne, Institute of Chemical Sciences and Engineering GPAO, Station 6, CH 1015 Lausanne (Switzerland)

2014-09-15

The photo-disinfection of water from two different wells (W1, pH: 4.6–5.1 ± 0.02) and (W2 pH: 5.6–5.7 ± 0.02) was carried out during the rainy season at Ouagadougou–Burkina Faso, West Africa. The weather variation during the rainy season significantly affects the photo-disinfection processes (solar disinfection and photo-Fenton). The dilution of the water by rainwater highly affected the chemical composition of the wells' water used in this study; very low iron contents Compared to the ones recorded during the dry season were recorded in all water samples. Both photo-disinfection processes were used to treat 25 L of water in a compound parabolic collector (CPC). None of them have shown the total inactivation of both wild enteric bacteria strains (total coliforms/E. coli and Salmonella spp.) involved in the treatment. However, the total coliforms/E. coli strains were totally inactivated during the exposure under most of the photo-Fenton treatment. Also, the remaining strains, especially those of Salmonella spp. were achieved during the subsequent 24 h of dark storage under the action of the Fenton process. Under uniquely solar radiation, total inactivation was recorded only in the total coliforms/E. coli strains. The impact of the available irradiance on the efficiency of the photo-Fenton disinfection of natural water was highlighted during the exposure under high intermittent solar radiation. The impact of the HCO{sub 3}{sup −} concentration of both wells' water on the evolution of the pH during the photo-disinfection was recorded. Drastic decrease was noticed after the initial fast increase in presence of low HCO{sub 3}{sup −} concentration while a steady state was observed after the increase in presence of higher concentration. The redox activities of the nitrogen components of the water during both photo-disinfection processes have led to increased concentration of nitrite in all the cases and variations were noticed in that of nitrate and

Evaluation of the efficiency of the photo Fenton disinfection of natural drinking water source during the rainy season in the Sahelian region

International Nuclear Information System (INIS)

Ndounla, J.; Pulgarin, C.

2014-01-01

The photo-disinfection of water from two different wells (W1, pH: 4.6–5.1 ± 0.02) and (W2 pH: 5.6–5.7 ± 0.02) was carried out during the rainy season at Ouagadougou–Burkina Faso, West Africa. The weather variation during the rainy season significantly affects the photo-disinfection processes (solar disinfection and photo-Fenton). The dilution of the water by rainwater highly affected the chemical composition of the wells' water used in this study; very low iron contents Compared to the ones recorded during the dry season were recorded in all water samples. Both photo-disinfection processes were used to treat 25 L of water in a compound parabolic collector (CPC). None of them have shown the total inactivation of both wild enteric bacteria strains (total coliforms/E. coli and Salmonella spp.) involved in the treatment. However, the total coliforms/E. coli strains were totally inactivated during the exposure under most of the photo-Fenton treatment. Also, the remaining strains, especially those of Salmonella spp. were achieved during the subsequent 24 h of dark storage under the action of the Fenton process. Under uniquely solar radiation, total inactivation was recorded only in the total coliforms/E. coli strains. The impact of the available irradiance on the efficiency of the photo-Fenton disinfection of natural water was highlighted during the exposure under high intermittent solar radiation. The impact of the HCO 3 − concentration of both wells' water on the evolution of the pH during the photo-disinfection was recorded. Drastic decrease was noticed after the initial fast increase in presence of low HCO 3 − concentration while a steady state was observed after the increase in presence of higher concentration. The redox activities of the nitrogen components of the water during both photo-disinfection processes have led to increased concentration of nitrite in all the cases and variations were noticed in that of nitrate and ammonia. - Graphical

UV disinfection for reuse applications in North America.

Science.gov (United States)

Sakamoto, G; Schwartzel, D; Tomowich, D

2001-01-01

In an effort to conserve and protect limited water resources, the States of Florida and California have actively promoted wastewater reclamation and have implemented comprehensive regulations covering a range of reuse applications. Florida has a semi-tropical climate with heavy summer rains that are lost due to run off and evaporation. Much of California is arid and suffers periodic droughts, low annual rainfall and depleted ground water supplies. The high population density combined with heavy irrigation demands has depleted ground water supplies resulting in salt-water intrusion. During the past decade, Florida reuse sites have increased dramatically from 118 to 444 plants representing a total flow capacity of 826 MGD. California presently has over 250 plants producing 1 BGD with a projected increase of 160 sites over the next 20 years. To prevent the transmission of waterborne diseases, disinfection of reclaimed water is controlled by stringent regulations. Many states regulate wastewater treatment processes, nutrient removal, final effluent quality and disinfection criteria based upon the specific reuse application. As a rule, the resulting effluents have low turbidity and suspended solids. For such effluents, UV technology can economically achieve the most stringent disinfection targets that are required by the States of California and Florida for restricted and unrestricted reuse. This paper compares UV disinfection for wastewater reuse sites in California and Florida and discusses the effect of effluent quality on UV disinfection.

Test methods for estimating the efficacy of the fast-acting disinfectant peracetic acid on surfaces of personal protective equipment.

Science.gov (United States)

Lemmer, K; Howaldt, S; Heinrich, R; Roder, A; Pauli, G; Dorner, B G; Pauly, D; Mielke, M; Schwebke, I; Grunow, R

2017-11-01

The work aimed at developing and evaluating practically relevant methods for testing of disinfectants on contaminated personal protective equipment (PPE). Carriers were prepared from PPE fabrics and contaminated with Bacillus subtilis spores. Peracetic acid (PAA) was applied as a suitable disinfectant. In method 1, the contaminated carrier was submerged in PAA solution; in method 2, the contaminated area was covered with PAA; and in method 3, PAA, preferentially combined with a surfactant, was dispersed as a thin layer. In each method, 0·5-1% PAA reduced the viability of spores by a factor of ≥6 log 10 within 3 min. The technique of the most realistic method 3 proved to be effective at low temperatures and also with a high organic load. Vaccinia virus and Adenovirus were inactivated with 0·05-0·1% PAA by up to ≥6 log 10 within 1 min. The cytotoxicity of ricin was considerably reduced by 2% PAA within 15 min of exposure. PAA/detergent mixture enabled to cover hydrophobic PPE surfaces with a thin and yet effective disinfectant layer. The test methods are objective tools for estimating the biocidal efficacy of disinfectants on hydrophobic flexible surfaces. © 2017 The Society for Applied Microbiology.

Resistance of bacterial biofilms formed on stainless steel surface to disinfecting agent.

Science.gov (United States)

Królasik, Joanna; Zakowska, Zofia; Krepska, Milena; Klimek, Leszek

2010-01-01

The natural ability of microorganisms for adhesion and biofilm formation on various surfaces is one of the factors causing the inefficiency of a disinfection agent, despite its proven activity in vitro. The aim of the study was to determine the effectiveness of disinfecting substances on bacterial biofilms formed on stainless steel surface. A universally applied disinfecting agent was used in the tests. Bacterial strains: Listeria innocua, Pseudomonas putida, Micrococcus luteus, Staphylococcus hominis strains, were isolated from food contact surfaces, after a cleaning and disinfection process. The disinfecting agent was a commercially available acid specimen based on hydrogen peroxide and peroxyacetic acid, the substance that was designed for food industry usage. Model tests were carried out on biofilm formed on stainless steel (type 304, no 4 finish). Biofilms were recorded by electron scanning microscope. The disinfecting agent in usable concentration, 0.5% and during 10 minutes was ineffective for biofilms. The reduction of cells in biofilms was only 1-2 logarithmic cycles. The use of the agent in higher concentration--1% for 30 minutes caused reduction of cell number by around 5 logarithmic cycles only in the case of one microorganism, M. luteus. For other types: L. innocua, P. putida, S. hominis, the requirements placed on disinfecting agents were not fulfilled. The results of experiments proved that bacterial biofilms are resistant to the disinfectant applied in its operational parameters. Disinfecting effectiveness was achieved after twofold increase of the agent's concentration.

Disinfection of sewage

International Nuclear Information System (INIS)

Arenas, J.

1984-01-01

Laboratory studies at IPEN and SEDAPAL have shown the effectiveness disinfection of sewage by means of ionizing radiations. A dose of 1 Kilo Gray reduces the coliforms and salmonella under the permissible levels. This method should allow to use again the liquids in the agriculture or its disposal like sea nutrient

Disinfection of a probe used in ultrasound-guided prostate biopsy.

Science.gov (United States)

Rutala, William A; Gergen, Maria F; Weber, David J

2007-08-01

Transrectal ultrasound (TRUS)-guided prostate biopsies are among the most common outpatient diagnostic procedures in urology clinics and carry the risk of introducing pathogens that may lead to infection. To investigate the effectiveness of procedures for disinfecting a probe used in ultrasound-guided prostate biopsy. The effectiveness of disinfection was determined by inoculating 10(7) colony forming units (cfu) of Pseudomonas aeruginosa at the following 3 sites on the probe: the interior lumen of the biopsy needle guide, the outside surface of the biopsy needle guide, and the interior lumen of the ultrasound probe where the needle guide passes through the transducer. Each site was investigated separately. After inoculation, the probe was immersed in 2% glutaraldehyde for 20 minutes and then assessed for the level of microbial contamination. The results demonstrated that disinfection (ie, a reduction in bacterial load of greater than 7 log(10) cfu) could be achieved if the needle guide was removed from the probe. However, if the needle guide was left in the probe channel during immersion in 2% glutaraldehyde, disinfection was not achieved (ie, the reduction was approximately 1 log(10) cfu). Recommendations for probe disinfection are provided and include disassembling the device and immersing the probe and the needle guide separately in a high-level disinfectant.

Efficiency of hydrogen peroxide in improving disinfection of ICU rooms.

Science.gov (United States)

Blazejewski, Caroline; Wallet, Frédéric; Rouzé, Anahita; Le Guern, Rémi; Ponthieux, Sylvie; Salleron, Julia; Nseir, Saad

2015-02-02

The primary objective of this study was to determine the efficiency of hydrogen peroxide (H₂O₂) techniques in disinfection of ICU rooms contaminated with multidrug-resistant organisms (MDRO) after patient discharge. Secondary objectives included comparison of the efficiency of a vaporizator (HPV, Bioquell) and an aerosolizer using H₂O₂, and peracetic acid (aHPP, Anios) in MDRO environmental disinfection, and assessment of toxicity of these techniques. This prospective cross-over study was conducted in five medical and surgical ICUs located in one University hospital, during a 12-week period. Routine terminal cleaning was followed by H₂O₂ disinfection. A total of 24 environmental bacteriological samplings were collected per room, from eight frequently touched surfaces, at three time-points: after patient discharge (T0), after terminal cleaning (T1) and after H₂O₂ disinfection (T2). In total 182 rooms were studied, including 89 (49%) disinfected with aHPP and 93 (51%) with HPV. At T0, 15/182 (8%) rooms were contaminated with at least 1 MDRO (extended spectrum β-lactamase-producing Gram-negative bacilli 50%, imipenem resistant Acinetobacter baumannii 29%, methicillin-resistant Staphylococcus aureus 17%, and Pseudomonas aeruginosa resistant to ceftazidime or imipenem 4%). Routine terminal cleaning reduced environmental bacterial load (P disinfection efficiency.

Radiation induced chemical changes in and disinfection of organic wastes suitable for supplemental feed

International Nuclear Information System (INIS)

Groneman, A.F.

1980-01-01

Ionizing radiation has been found to disinfect organic wastes and simultaneously ease the separation of suspended solids from water. Because these effects can have important favourable impacts on the technology of upgrading organic wastes to animal feed or fertilizers, experimental studies are reported on the rationale of effects of gamma irradiation or disinfection and separation of the solid and the liquid phase of organic waste systems. The radiation inactivation of microorganisms occurs by direct and indirect action. Mechanisms of inactivation are discussed and measures are proposed how the indirect action of the radiation inactivation of microorganisms can be increased. Effects of gamma irradiation on dewatering properties of organic wastes were indirectly caused by the oxidizing OH radicals produced by the irradiation of water. OH radicals react with organic components of the solid phase which leads to their solubilisation resulting in an increase of the total organic carbon concentration in the liquid phase. Results of a mutagenicity test indicate that the solvated compounds exhibited no mutagenic activity. Microbiological case studies on the disinfection and upgrading of liquid and solid organic wastes to animal feed are discussed and the acceptance of radiation processing is evaluated. (Auth.)

Drinking water contamination and it's disinfection

International Nuclear Information System (INIS)

Shah, P.M.J.

2005-01-01

High quality water is necessary for the survival of human life. In this paper, an effort has been made to highlight the various causes of water contamination. Some of the most common impurities present in water are pathogenic microorganisms along with organize and in organize pollutants. Different treatment methods are adopted to ensure the potability of water. They include physical, chemical and ultra viable treatment along with solar disinfection etc. The adoption of a particular disinfection strategy depends on the level of treatment required and the resources available to carry out such a treatment. (author)

Oxidation of diclofenac by aqueous chlorine dioxide: identification of major disinfection byproducts and toxicity evaluation.

Science.gov (United States)

Wang, Yingling; Liu, Haijin; Liu, Guoguang; Xie, Youhai

2014-03-01

Diclofenac (DCF), a synthetic non-steroidal anti-inflammatory drug, is one of the most frequently detected pharmaceuticals in the aquatic environment. In this work, the mechanism and toxicity of DCF degradation by ClO2 under simulated water disinfection conditions were investigated. Experimental results indicate that rapid and significant oxidation of DCF occurred within the first few minutes; however, its mineralization process was longer than its degradation process. UPLC-MS and (1)H NMR spectroscopy were performed to identify major disinfection byproducts that were generated in three tentative degradation routes. The two main routes were based on initial decarboxylation of DCF on the aliphatic chain and hydroxylation of the phenylacetic acid moiety at the C-4 position. Subsequently, the formed aldehyde intermediates were the starting point for further multistep degradation involving decarboxylation, hydroxylation, and oxidation reactions of CN bond cleavage. The third route was based on transient preservation of chlorinated derivatives resulting from electrophilic attack by chlorine on the aromatic ring, which similarly underwent CN bond cleavage. Microtox bioassay was employed to evaluate the cytotoxicity of solutions treated by ClO2. The formation of more toxic mid-byproducts during the ClO2 disinfection process poses a potential risk to consumers. Copyright © 2013 Elsevier B.V. All rights reserved.

Roughness comparison of heat cured type of acrylic resin in disinfectant solution immersion (Immersion in a solution of alkaline peroxide and 75% Celery extract (Apium graveolens L

Directory of Open Access Journals (Sweden)

Dewi Puspitasari

2016-08-01

Full Text Available Acrylic resin denture base has the properties absorbing that affecting physical and mechanical properties. One of the physical properties of acrylic resin is surface roughness. The aim of the study was to find out the roughness effect on heat cured acrylic that was immersed in alkaline peroxide and 75% celery (Apium graveoens L extract as a disinfectant solution. The study was a true experimental and posttest with control group designed with a rectangular shape size 65 x 10 x 3.3 mm based on the ISO standard 1567, six samples were used for alkaline peroxide, celery extract 75% and aquadest group for 5 and 15 days. A Surface Roughness Tester was used for the surface roughness changes observation. The statistical test used One-way ANOVA and post hoc Bonferroni. The results of this study showed the value of roughness on 5 days for alkaline peroxide (1.51 µm is greater than celery extract (0.36µm and aquadest (0.30 µm. The soaking for 15 days in alkaline peroxide (1.52 µm is greater than 75% celery extracts (0.38 µm and aquadest (0.34 µm. Alkaline peroxide caused higher roughness value of heat cured acrylic resin than 75% celery extract.

Evaluation of disinfectants in the domestic environment under 'in use' conditions.

Science.gov (United States)

Scott, E.; Bloomfield, S. F.; Barlow, C. G.

1984-01-01

An 'in use' test was developed to investigate effectiveness of disinfectant application and of detergent of hot water cleaning at kitchen, bathroom and toilet sites in the domestic environment. Detergent and hot water cleaning produced no observable reduction in microbial contamination. Single and daily application tests demonstrated that hypochlorite and phenolic disinfectants can be used to produce substantial reductions in bacterial contamination in the home. Results indicate that maximum protection afforded by disinfection is relatively brief; 3-6 h after disinfection, contamination levels were only marginally less than those observed at pretreatment. Some suggestions are made for improvements in home hygiene. PMID:6323576

Effectiveness of Disinfectants on Antimicrobial and Physical Properties of Dental Impression Materials.

Science.gov (United States)

Demajo, Jean Karl; Cassar, Valter; Farrugia, Cher; Millan-Sango, David; Sammut, Charles; Valdramidis, Vasilis; Camilleri, Josette

2016-01-01

The aim of this study was to assess the antimicrobial activity of chemical disinfectants on alginate and silicone impression materials. The effect of chemical disinfectants on the dimensional stability of the impression materials was also assessed. For the microbiologic assessment, impressions of the maxillary arch were taken from 14 participants, 7 using alginate and 7 using an addition silicone. The impressions were divided into three sections. Each section was subjected to spraying with MD 520 or Minuten or no disinfection (control), respectively. Antimicrobial action of the chemical disinfectants was assessed by measuring microbial counts in trypticase soy agar (TSA) media and expressing the results in colony-forming units/cm2. The surface area of the dental impressions was calculated by scanning a stone cast using computer-aided design/computer-assisted manufacture and analyzing the data using a custom computer program. The dimensional stability of the impression materials after immersion in disinfectants was assessed by measuring the linear displacement of horizontally restrained materials using a traveling microscope. The percent change in length over 3 hours was thus determined. Alginate exhibited a higher microbial count than silicone. MD 520 eliminated all microbes as opposed to Minuten. The bacterial growth after Minuten disinfection was almost twice as much for alginate than for addition silicone impressions. The chemical disinfectants affected the alginate dimensional stability. Minuten reduced the shrinkage sustained by alginate during the first hour of storage. Alginate harbors three times more microorganisms than silicone impression material. Chemical disinfection by glutaraldehyde-based disinfectant was effective in eliminating all microbial forms for both alginate and silicone without modifying the dimensional stability. Alcohol-based disinfectants, however, reduced the alginate shrinkage during the first 90 minutes of setting. The current studies

Modern technologies for improving cleaning and disinfection of environmental surfaces in hospitals

Directory of Open Access Journals (Sweden)

John M. Boyce

2016-04-01

Full Text Available Abstract Experts agree that careful cleaning and disinfection of environmental surfaces are essential elements of effective infection prevention programs. However, traditional manual cleaning and disinfection practices in hospitals are often suboptimal. This is often due in part to a variety of personnel issues that many Environmental Services departments encounter. Failure to follow manufacturer’s recommendations for disinfectant use and lack of antimicrobial activity of some disinfectants against healthcare-associated pathogens may also affect the efficacy of disinfection practices. Improved hydrogen peroxide-based liquid surface disinfectants and a combination product containing peracetic acid and hydrogen peroxide are effective alternatives to disinfectants currently in widespread use, and electrolyzed water (hypochlorous acid and cold atmospheric pressure plasma show potential for use in hospitals. Creating “self-disinfecting” surfaces by coating medical equipment with metals such as copper or silver, or applying liquid compounds that have persistent antimicrobial activity surfaces are additional strategies that require further investigation. Newer “no-touch” (automated decontamination technologies include aerosol and vaporized hydrogen peroxide, mobile devices that emit continuous ultraviolet (UV-C light, a pulsed-xenon UV light system, and use of high-intensity narrow-spectrum (405 nm light. These “no-touch” technologies have been shown to reduce bacterial contamination of surfaces. A micro-condensation hydrogen peroxide system has been associated in multiple studies with reductions in healthcare-associated colonization or infection, while there is more limited evidence of infection reduction by the pulsed-xenon system. A recently completed prospective, randomized controlled trial of continuous UV-C light should help determine the extent to which this technology can reduce healthcare-associated colonization and infections

Evaluation of different sterilization and disinfection methods on commercially made preformed crowns.

Science.gov (United States)

Yilmaz, Y; Guler, C

2008-12-01

The aim of this study was to evaluate the changes caused by different sterilization or disinfection methods on the vestibular surface of four commercially made preformed crowns using stereomicroscopy and scanning electron microscopy (SEM). Preformed crowns (NuSmile Primary Anterior Crown (NSC), Kinder Krowns (KK), Pedo Pearls (PP) and polycarbonate crowns (PC)) were sterilized and/or disinfected by one of the following techniques: no sterilization or disinfection (G1 control group); steam autoclaving at 134 degrees C (30 psi) for 4 min (G2); steam autoclaving at 134 degrees C (30 psi) for 12 min (G3); steam autoclaving at 121 degrees C (15 psi) for 30 min (G4); and ultrasonication in a bath containing 4% Lysetol AF for 5 min at room temperature (chemical disinfection) (G5). Scanning electron micrographs of the crowns were taken before and after their sterilization or disinfection. The changes on the vestibular surface were then scored for the presence or absence of crazing, contour alteration, fracturing, and vestibular surface changes. The data were analyzed statistically using the chi-square test. No changes were observed before and after sterilization or disinfection in the stereomicroscopic evaluation of the vestibular surface of the crowns. However, all methods in which steam autoclaving was used to sterilize the crowns caused significant (P < 0.05) crazing and contour alterations of the vestibular surface of the crowns when they were examined by SEM. Chemical disinfection using an aldehyde-free disinfectant is the preferred method of disinfection for crowns that have been used previously in other dental patients.

Ozone reactions with indoor materials during building disinfection

DEFF Research Database (Denmark)

Poppendieck, D.; Hubbard, H.; Ward, M.

2007-01-01

, and particularly after several hours of disinfection, surface reaction resistance dominated the overall resistance to ozone deposition for nearly all materials. Total building disinfection by-products (all carbonyls) were quantified per unit area of each material for the experimental period. Paper, office...... partition, and medium density fiberboard each released greater than 38 mg m(-2) of by-products....

9 CFR 77.41 - Cleaning and disinfection of premises, conveyances, and materials.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfection of premises... PRODUCTS TUBERCULOSIS Captive Cervids § 77.41 Cleaning and disinfection of premises, conveyances, and... health officials. Cleaning and disinfection must be completed before the premises, conveyances, or...

Resistance to disinfection of a polymicrobial association contaminating the surface of elastomeric dental impressions.

Science.gov (United States)

Giammanco, Giovanni M; Melilli, Dario; Rallo, Antonio; Pecorella, Sonia; Mammina, Caterina; Pizzo, Giuseppe

2009-04-01

The aim of this study was to evaluate the ability to resist disinfection of a polymicrobial association contaminating the surface of dental impressions obtained with two different elastomers: a polyether (Impregum) and an addition-polymerized silicone (Elite). Impressions were contaminated with a mixture of three biofilm-forming microorganisms (Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans) and disinfected immediately after contamination, or after microbial layers were allowed to develop during a six-hour storage. Two commercial disinfectants were tested: MD 520 containing 0.5% glutaraldehyde and Sterigum Powder without glutaraldehyde. Residual contamination was recovered by mechanical rinsing immediately after disinfection and after a six-hour storage of disinfected impressions, and assessed by colony counting. Both disinfectants tested were shown to be effective in reducing the microbial presence on the impression materials, achieving at least a 102 reduction of microbial counts compared to water rinsing. However, Sterigum was generally less effective on the Elite elastomer and could not grant disinfection on six-hour aged P. aeruginosa and C. albicans microbial layers. The results of this study suggest that the materials used for the impressions influence the efficacy of disinfection. Disinfectants should be tested according to conditions encountered in everyday clinical practice and the need for immediate disinfection of impressions should be clearly indicated by manufacturers.

Experience of using heat citric acid disinfection method in central dialysis fluid delivery system.

Science.gov (United States)

Sakuma, Koji; Uchiumi, Nobuko; Sato, Sumihiko; Aida, Nobuhiko; Ishimatsu, Taketo; Igoshi, Tadaaki; Kodama, Yoshihiro; Hotta, Hiroyuki

2010-09-01

We applied the heat citric acid disinfection method in the main part of the central dialysis fluid delivery system (MPCDDS), which consists of a multiple-patient dialysis fluid supply unit, dialysis console units, and dialysis fluid piping. This disinfection method has been used for single-patient dialysis machines, but this is the first trial in the MPCDDS. We examined, by points of safety and disinfection effect, whether this disinfection method is comparable to conventional disinfection methods in Japan. The conventional disinfection method is a combination of two disinfectants, sodium hypochlorite and acetic acid, used separately for protein removal and decalcification. Consequently, total microbial counts and endotoxin concentrations fully satisfied the microbiological requirements for standard dialysis fluid of ISO 11663. From our results and discussion, this heat citric acid disinfection method is proved to be safe and reliable for MPCDDS. However, to satisfy the microbiological requirements for ultrapure dialysis fluid, further consideration for this method in MPCDDS including the reverse osmosis device composition and piping is necessary.

[Scanning electron microscope study of chemically disinfected endodontic files].

Science.gov (United States)

Navarro, G; Mateos, M; Navarro, J L; Canalda, C

1991-01-01

Forty stainless steel endodontic files were observed at scanning electron microscopy after being subjected to ten disinfection cycles of 10 minutes each one, immersed in different chemical disinfectants. Corrosion was not observed on the surface of the files in circumstances that this study was made.

9 CFR 77.19 - Cleaning and disinfection of premises, conveyances, and materials.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfection of premises... PRODUCTS TUBERCULOSIS Cattle and Bison § 77.19 Cleaning and disinfection of premises, conveyances, and... health officials. Cleaning and disinfection must be completed before the premises, conveyances, or...

Evaluation of possible use of disinfectant based on chlorine dioxide in dairy plant

Directory of Open Access Journals (Sweden)

Rakić-Martinez Mira

2009-01-01

Full Text Available Poor sanitation of food contact surfaces has been a contributing factor in food borne disease outbreaks, especially those involving Listeria monocytogenes, Salmonella spp., Escherichia coli, Staphylococcus aureus etc. The objectives of this study were therefore to: 1. Determine the efficiency of a disinfectant based on chlorine dioxide in suspension in a closed system in a dairy plant. 2. Evaluate the possibility of disinfection of working surfaces with a disinfectant based on chlorine dioxide. In order to determine the germicidal effect of the disinfectant based on chlorine dioxide by suspension test (BSEN 1276:1997; the following test organisms were used: Listeria monocytogenes, Proteus mirabilis, Escherichia coli, Bacillus cereus, Staphylococcus aureus and Pseudomonas aeruginosa clinical isolate. The corrosive properties of the disinfectant based on chlorine dioxide were tested by IDF 077:1977 standard. The efficacy of this disinfectant was investigated in a closed system in a dairy plant. Results indicated a 100% reduction of >108 cfu/ml L. monocytogenes, E. coli, Proteus mirabilis, Pseudomonas aeruginosa, S. aureus, viable count after 1 minute of exposure to 100 ppm of the disinfectant based on chlorine dioxide and 400 ppm for Bacillus cereus. In the presence of 2% skim milk and 4 % skim milk concentrations of 200 and 250 ppm resulted in 100% reduction in numbers of the five of six test microorganisms, respectively. The spore former, Bacillus cereus is less susceptible to the disinfectant. Therefore, the efficient concentration for 100% reduction in viable count after 1 minute exposure was 500 ppm. The corrosive properties of the disinfectant were not determined. In the case of closed system disinfection in a dairy plant, reduction in viable count after 15 minute exposure to 100 ppm of disinfectant based on chlorine dioxide ranged from 80 to 100%.

Evaluation of disinfection efficiency in pet's hospital by using chlorine dioxide

Directory of Open Access Journals (Sweden)

Ching-Shan Hsu

2016-07-01

Full Text Available Microbial aerosols could cause various human and animal health problems and their control is becoming a significant scientific and technological topic for consideration. The main objectives of this study were to monitor bioaerosol levels of the pet's hospital and then to perform disinfection efficiency by applying chlorine dioxide. The air quality within these pet's hospitals should satisfy the guidelines specified by the Taiwan Environmental Protection Administration (TEPA. Accordingly, this study performed an experimental investigation into the efficiency of two different gaseous chlorine dioxide (0.3 mg m−3 treatments in disinfecting a local pet's hospital, namely a single, one-off application and a multiple-daily application. In both cases, the ClO2 was applied using strategically-placed aerosol devices. The air quality before and after disinfection was evaluated by measuring the bioaerosol levels of bacteria and fungi. The experimental results found that the average background levels of bacteria and fungi prior to ClO2 disinfection were found to be 2014 ± 1350 and 1002 ± 669 CFU m−3, respectively. A single ClO2 application was found to total disinfected bacteria and fungi concentration levels by as much as 57.3 and 57.6%. By contrast, a multiple-daily ClO2 application was found to total disinfected bacteria and fungi concentration levels by as much as 65.1 and 57.6%. Among the two disinfection methods, the multiple-daily ClO2 application method was found to yield a higher disinfection efficiency for bacteria, i.e., 16.28 ± 0.92%. Thus, using a ClO2 disinfectant to maintain the air quality is of great importance to reduce infectious diseases in the pet's hospital. Therefore, the results suggest that the air quality guidelines prescribed by the TEPA for pet's hospital and other animal facilities can best be achieved by applying chlorine dioxide at regular intervals. The ClO2 aerosol devices can effectively restrain or

Effectiveness of Surface Cleaning and Disinfection in a Brazilian Healthcare Facility

Science.gov (United States)

Santos-Junior, Aires G.; Ferreira, Adriano M.; Frota, Oleci P.; Rigotti, Marcelo A.; Barcelos, Larissa da S.; Lopes de Sousa, Alvaro Francisco; de Andrade, Denise; Guerra, Odanir G.; R. Furlan, Mara C.

2018-01-01

Background: Failures in the processes of cleaning and disinfecting health service surfaces may result in the spread and transfer of pathogens that are often associated with healthcare-related infections and outbreaks. Aims: To assess the effectiveness of environmental surface cleaning and disinfection in a hospital clinic. Method: The study was conducted in a nursing ward with 45 beds. A total of 80 samples from five high-touch surfaces were evaluated before and after cleaning and disinfection, using the following methods: visual inspection, adenosine triphosphate bioluminescence assay, aerobic colony count, Staphylococcus aureus colony count, and evaluation of resistance to methicillin. The data analysis used nonparametric comparative and correlative tests to observe any differences in the pre- and post- cleaning and disinfection results for the surfaces assessed. Results: Effective cleaning and disinfection had a significant effect on only two surfaces when measured for the presence of adenosine triphosphate, the inner bathroom door handle (p=0.007) and the toilet bowl (p=0.01). When evaluated for Staphylococcus aureus colony count, the toilet flush handle also demonstrated a significant effect (p=0.04). Conclusion: The effectiveness of cleaning and disinfection of the surfaces tested was not satisfactory. An educational intervention is recommended for the cleaning and disinfection staff and the nursing team at the healthcare facility. Relevance to Clinical Practice: The data in the study revealed that daily hospital cleaning and disinfection in the sampled sites are not sufficient in medical and surgical wards. Hospital cleanliness must be reevaluated from the point of view of materials, such as an adequate supply of clean cloths, in addition to establishing more precise cleanliness protocols and accurate monitoring systems. PMID:29643951

Effectiveness of Surface Cleaning and Disinfection in a Brazilian Healthcare Facility.

Science.gov (United States)

Santos-Junior, Aires G; Ferreira, Adriano M; Frota, Oleci P; Rigotti, Marcelo A; Barcelos, Larissa da S; Lopes de Sousa, Alvaro Francisco; de Andrade, Denise; Guerra, Odanir G; R Furlan, Mara C

2018-01-01

Failures in the processes of cleaning and disinfecting health service surfaces may result in the spread and transfer of pathogens that are often associated with healthcare-related infections and outbreaks. To assess the effectiveness of environmental surface cleaning and disinfection in a hospital clinic. The study was conducted in a nursing ward with 45 beds. A total of 80 samples from five high-touch surfaces were evaluated before and after cleaning and disinfection, using the following methods: visual inspection, adenosine triphosphate bioluminescence assay, aerobic colony count, Staphylococcus aureus colony count, and evaluation of resistance to methicillin. The data analysis used nonparametric comparative and correlative tests to observe any differences in the pre- and post- cleaning and disinfection results for the surfaces assessed. Effective cleaning and disinfection had a significant effect on only two surfaces when measured for the presence of adenosine triphosphate, the inner bathroom door handle ( p =0.007) and the toilet bowl ( p =0.01). When evaluated for Staphylococcus aureus colony count, the toilet flush handle also demonstrated a significant effect ( p =0.04). The effectiveness of cleaning and disinfection of the surfaces tested was not satisfactory. An educational intervention is recommended for the cleaning and disinfection staff and the nursing team at the healthcare facility. The data in the study revealed that daily hospital cleaning and disinfection in the sampled sites are not sufficient in medical and surgical wards. Hospital cleanliness must be reevaluated from the point of view of materials, such as an adequate supply of clean cloths, in addition to establishing more precise cleanliness protocols and accurate monitoring systems.

Comparison of electrochemical method with ozonation, chlorination and monochloramination in drinking water disinfection

Energy Technology Data Exchange (ETDEWEB)

Li Hongna, E-mail: lihongna@gmail.com [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China); Zhu Xiuping [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China); Ni Jinren, E-mail: nijinren@iee.pku.edu.cn [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China)

2011-11-30

Highlights: > Electrochemical, O{sub 3}, NaClO and NH{sub 2}Cl were compared at respective optimal condition. > Disinfection efficacy was similar for different bacteria in electrolysis. > Harsh Bacillus was inactivated more difficult in O{sub 3}, NaClO and NH{sub 2}Cl system. > Efficient disinfection of electrolysis was attributed to nonselectivity of {center_dot}OH. > Cell surface damage was more obvious in electrochemical process than the others. - Abstract: Electrochemical process in chloride-free electrolytes was proved to be powerful in disinfection due to the strong oxidants produced in the electrolysis and no formation of disinfection byproducts (DBPs). In this study, disinfection experiments were conducted by electrochemical treatment compared with ordinary and advanced methods (ozonation, chlorination and monochloramination), with Escherichia coli (E. coli) K-12, Staphylococcus aureus (S. aureus) A106, Bacillus subtilis (BST) and an isolated Bacillus as the representative microorganisms. Firstly, factor tests were performed on E. coli to obtain the optimal conditions of the four disinfection procedures. At their respective optimal condition, CT (concentration of disinfectant x contact time) value of a 4-log E. coli inactivation was 33.5, 1440, 1575, 1674 mg min L{sup -1} for electrochemical process, ozonation, chlorination and monochloramination, respectively. It was demonstrated that the disinfection availability was in the following order: electrochemical process > ozonation > chlorination > monochloramination, which could be attributed to the hydroxyl radical generated in the electrolysis, with strong oxidizing ability and non-selectivity compared with the other three disinfectants. Moreover, the disinfection efficacy of the four disinfection procedures was compared for four different bacteria. It was found that the disinfection efficacy was similar for the selected four bacteria in electrochemical process, while in the other three treatments

Comparison of electrochemical method with ozonation, chlorination and monochloramination in drinking water disinfection

International Nuclear Information System (INIS)

Li Hongna; Zhu Xiuping; Ni Jinren

2011-01-01

Highlights: → Electrochemical, O 3 , NaClO and NH 2 Cl were compared at respective optimal condition. → Disinfection efficacy was similar for different bacteria in electrolysis. → Harsh Bacillus was inactivated more difficult in O 3 , NaClO and NH 2 Cl system. → Efficient disinfection of electrolysis was attributed to nonselectivity of ·OH. → Cell surface damage was more obvious in electrochemical process than the others. - Abstract: Electrochemical process in chloride-free electrolytes was proved to be powerful in disinfection due to the strong oxidants produced in the electrolysis and no formation of disinfection byproducts (DBPs). In this study, disinfection experiments were conducted by electrochemical treatment compared with ordinary and advanced methods (ozonation, chlorination and monochloramination), with Escherichia coli (E. coli) K-12, Staphylococcus aureus (S. aureus) A106, Bacillus subtilis (BST) and an isolated Bacillus as the representative microorganisms. Firstly, factor tests were performed on E. coli to obtain the optimal conditions of the four disinfection procedures. At their respective optimal condition, CT (concentration of disinfectant x contact time) value of a 4-log E. coli inactivation was 33.5, 1440, 1575, 1674 mg min L -1 for electrochemical process, ozonation, chlorination and monochloramination, respectively. It was demonstrated that the disinfection availability was in the following order: electrochemical process > ozonation > chlorination > monochloramination, which could be attributed to the hydroxyl radical generated in the electrolysis, with strong oxidizing ability and non-selectivity compared with the other three disinfectants. Moreover, the disinfection efficacy of the four disinfection procedures was compared for four different bacteria. It was found that the disinfection efficacy was similar for the selected four bacteria in electrochemical process, while in the other three treatments inactivation of the two

Formation of H2O2 at UV-photolysis of water solutions of phenol

International Nuclear Information System (INIS)

Guliyeva, U.A.; Gurbanov, M.A.; Mahmudov, H.M.

2013-01-01

Non-traditional methods, based on application of ionizing and UV-radiation widely used for cleaning of water solutions from toxic substances, including phenols. These methods have simultaneously effect including of disinfection and chemical cleaning of water solutions from various industrial processes

9 CFR 91.18 - Cleaning and disinfection of transport carriers for export.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfection of transport....18 Cleaning and disinfection of transport carriers for export. All fittings, utensils and equipment... port. Such disinfection of halters, ropes, and similar equipment used in handling and tying of animals...

Genotoxicity of drinking water treated with different disinfectants and effects of disinfection conditions detected by umu-test.

Science.gov (United States)

Nie, Xuebiao; Liu, Wenjun; Zhang, Liping; Liu, Qing

2017-06-01

The genotoxicity of drinking water treated with 6 disinfection methods and the effects of disinfection conditions were investigated using the umu-test. The pretreatment procedure of samples for the umu-test was optimized for drinking water analysis. The results of the umu-test were in good correlation with those of the Ames-test. The genotoxicity and production of haloacetic acids (HAAs) were the highest for chlorinated samples. UV+chloramination is the safest disinfection method from the aspects of genotoxicity, HAA production and inactivation effects. For chloramination, the effects of the mass ratio of Cl 2 to N of chloramine on genotoxicity were also studied. The changes of genotoxicity were different from those of HAA production, which implied that HAA production cannot represent the genotoxic potential of water. The genotoxicity per chlorine decay of chlorination and chloramination had similar trends, indicating that the reaction of organic matters and chlorine made a great contribution to the genotoxicity. The results of this study are of engineering significance for optimizing the operation of waterworks. Copyright © 2016. Published by Elsevier B.V.

One plunge or two?--hand disinfection with alcohol gel.

Science.gov (United States)

Macdonald, Duncan J M; Mckillop, Elisabeth C A; Trotter, Sylvia; Gray, Alastair J R

2006-04-01

To compare health care workers' hand surface coverage using two different volumes of alcohol gel for hand disinfection. and methods. A total of 84 members of staff in our hospital were studied. Subjects were asked to disinfect their hands with alcohol gel containing a clear fluorescent substance. Performance was assessed by using UV light to identify areas which had been missed, and the total surface area missed was calculated. A total of 42 subjects received 3.5 ml of alcohol gel, and 42 age-, sex-, and job-matched subjects received 1.75 ml of alcohol gel. Significantly less area was missed when hand disinfecting with double the volume of alcohol gel; 1.23 versus 6.35% surface area was missed (P disinfection significantly improves the efficiency of coverage of the hands with alcohol gel. This may result in lower bacterial count on the hands and may reduce the spread of nosocomial infections including that of methicillin-resistant Staphylococcus aureus.

Observations on Salmonella contamination of commercial duck farms before and after cleaning and disinfection.

Science.gov (United States)

Martelli, Francesca; Gosling, Rebecca J; Callaby, Rebecca; Davies, Rob

2017-04-01

In the European Union, statutory control of Salmonella is in place in the chicken and turkey sectors, but not in the duck sector. In this study, 14 Salmonella-positive duck farms were sampled before and after cleaning and disinfection, and once the houses had been restocked with a new flock. The cleaning and disinfection programmes used were subdivided into two main categories: ones in which a final formaldehyde disinfection step was included (1) and ones in which it was not included (2). Several types of samples were collected during the study, and faecal samples were those more frequently positive (62% of faecal samples were positive for Salmonella in comparison to 2-23% of samples from all the other sample categories) (P cleaning and disinfection programme used, there was a statistically significant (P cleaning and disinfection (41.1%) and after cleaning and disinfection (3.1%). After restocking, the number of Salmonella-positive samples increased significantly (P disinfection programme 1 was used were 5.34 times less likely to have samples positive for Salmonella after cleaning and disinfection than farms which implemented programme 2. Formaldehyde acts effectively against Salmonella even in the presence of some residual organic matter. Limited residual contamination on farms after cleaning and disinfection represents a risk of infection for young ducklings, and thorough cleaning and disinfection procedures should be implemented to reduce the carry-over of infection between flocks.

Conventional and Alternative Disinfection Methods of Legionella in Water Distribution Systems – Review

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Pūle Daina

2016-12-01

Full Text Available Prevalence of Legionella in drinking water distribution systems is a widespread problem. Outbreaks of Legionella caused diseases occur despite various disinfectants are used in order to control Legionella. Conventional methods like thermal disinfection, silver/copper ionization, ultraviolet irradiation or chlorine-based disinfection have not been effective in the long term for control of biofilm bacteria. Therefore, research to develop more effective disinfection methods is still necessary.

Experimental evaluation of an automated endoscope reprocessor with in situ generation of peracetic acid for disinfection of semicritical devices.

Science.gov (United States)

Sattar, Syed A; Kibbee, Richard J; Tetro, Jason A; Rook, Tony A

2006-11-01

To evaluate the effectiveness of a high-level disinfection solution generated inside an endoscope processing system for decontaminating external and internal surfaces of experimentally contaminated heat-sensitive medical devices. The American Society for Testing and Materials Simulated-Use Test protocol (E1837-02), which incorporates a soil load in each inoculum, was used to evaluate the efficacy of the system when processing 4 common types of endoscopes contaminated separately with 5 types of nosocomial pathogens: Pseudomonas aeruginosa (ATCC 15442), spores of Clostridium difficile (ATCC 9689), a glutaraldehyde-resistant strain of Mycobacterium chelonae, a vancomycin-resistant strain of Enterococcus faecalis, and a methicillin-resistant strain of Staphylococcus aureus. Rinse solution samples from channels and from surfaces of the processed endoscopes were tested for any microbicidal residues. For all organisms tested, the baseline level of contamination of the endoscopes ranged from 5 log(10) to greater than 7 log(10) at each external surface site and internal channel. All tests showed reductions in viability of the test organisms to undetectable levels. All rinse solution samples from external and internal sites of the endoscopes proved to be free of any residual microbicidal activity. The endoscope reprocessor, with its processor-generated high-level disinfection solution, successfully reduced the numbers of selected, clinically relevant pathogens to undetectable levels both in the channels and on the outside surfaces of the 4 representative endoscopes tested in this study.

Effect of alginate chemical disinfection on bacterial count over gypsum cast.

Science.gov (United States)

Haralur, Satheesh B; Al-Dowah, Omir S; Gana, Naif S; Al-Hytham, Abdullah

2012-05-01

To evaluate the efficacy of sodium hypochlorite (1 : 10) and iodophor disinfectants on alginate impressions along with their effect on the survived bacterium count on the gypsum cast. Four alginate impression on each dentate patients were made, of which Group I were not washed or disinfected, Group II impressions were merely washed with water, Group III were disinfected by spraying with sodium hypochlorite (1 : 10), Group IV were disinfected with iodophor (1 : 213). Gypsum cast (type III) were made from all the impression. Impressions and gypsum cast were swabbed in mid palatal region for bacterial culture. Bacterial colony counting done after 3 days of incubation at 37℃ in blood agar media. The data obtained was analyzed by one way ANOVA test at a significant difference level of 0.05. Group I and Group II showed significantly more bacteria compared to Group III and Group IV. Bacterial colonies on the alginate impression and gypsum cast in group disinfected with Sodium hypochlorite (1 : 10) were 0.18, 0.82 respectively compared to group treated with iodophor (1 : 213). There was an increase in bacterial count on dental cast compared to source alginate impressions. Sodium hypochlorite (1 : 10) was found to be better disinfectant for alginate impression. There was an indication of increase in number of bacteria from alginate impression to making of dental cast. Additional gypsum cast disinfectant procedures need to be encouraged to completely eliminate cross infection to dental laboratory.

Efficacy of computer-based endoscope cleaning and disinfection using a hospital management information system.

Science.gov (United States)

Wang, Caixia; Chen, Yuanyuan; Yang, Feng; Ren, Jie; Yu, Xin; Wang, Jiani; Sun, Siyu

2016-08-01

The present study aimed to assess the efficacy of computer-based endoscope cleaning and disinfection using a hospital management information system (HMIS). A total of 2,674 gastroscopes were eligible for inclusion in this study. For the processes of disinfection management, the gastroscopes were randomly divided into 2 groups: gastroscope disinfection HMIS (GD-HMIS) group and manual group. In the GD-HMIS group, an integrated circuit card (IC card) chip was installed to monitor and record endoscope cleaning and disinfection automatically and in real time, whereas the endoscope cleaning and disinfection in the manual group was recorded manually. The overall disinfection progresses for both groups were recorded, and the total operational time was calculated. For the GD-HMIS group, endoscope disinfection HMIS software was successfully developed. The time to complete a single session of cleaning and disinfecting on a gastroscope was 15.6 minutes (range, 14.3-17.2 minutes) for the GD-HMIS group and 21.3 minutes (range, 20.2-23.9 minutes) for the manual group. Failure to record information, such as the identification number of the endoscope, occasionally occurred in the manual group, which affected the accuracy and reliability of manual recording. Computer-based gastroscope cleaning and disinfection using a hospital management information system could monitor the process of gastroscope cleaning and disinfection in real time and improve the accuracy and reliability, thereby ensuring the quality of gastroscope cleaning and disinfection. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

The antimicrobial activities of some commonly used disinfectants on ...

African Journals Online (AJOL)

The disinfectants; SavlonR, JikR, Methylated spirit and kerosene were observed for their inhibitory activities on Bacillus subtilis, Pseudomonas aeruginosa and Candida albicans. This was done by measuring the zone of inhibition of the disinfectants on the tested organisms. The results showed that Savlon was very effective ...

Disinfectant-susceptibility of multi-drug-resistant Mycobacterium tuberculosis isolated in Japan

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Noriko Shinoda

2016-02-01

Full Text Available Abstract Background Multi-drug-resistant Mycobacterium tuberculosis has been an important problem in public health around the world. However, limited information about disinfectant-susceptibility of multi-drug-resistant strain of M. tuberculosis was available. Findings We studied susceptibility of several Japanese isolates of multi-drug-resistant M. tuberculosis against disinfectants, which are commonly used in clinical and research laboratories. We selected a laboratory reference strain (H37Rv and eight Japanese isolates, containing five drug-susceptible strains and three multi-drug-resistant strains, and determined profiles of susceptibility against eight disinfectants. The M. tuberculosis strains were distinguished into two groups by the susceptibility profile. There was no relationship between multi-drug-resistance and disinfectant-susceptibility in the M. tuberculosis strains. Cresol soap and oxydol were effective against all strains we tested, regardless of drug resistance. Conclusions Disinfectant-resistance is independent from multi-drug-resistance in M. tuberculosis. Cresol soap and oxydol were effective against all strains we tested, regardless of drug resistance.

The effect of disinfectants on fungal diseases of potato and vegetables

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Hilkka Koponen

1993-03-01

Full Text Available Treatments of one and ten minutes were too short for all disinfectants against fungi in peat and plant debris. The best effect was achieved with a treatment of 90 min. Sodium hypochlorite (NaOCl was the most effective and Korsolin and Virkon S were the least effective in the control of Fusarium culmorum and F. oxysporum. Virkon S (2% was the most effective against Mycocentrospora acerina and Phoma foveata. Soaking for 15 min and 60 min in a disinfection suspension eradicated Botrytis cinerea and P. foveata totally from the contaminated plastic pots. Fusarium spp. were the most difficult fungi to disinfect and these were best controlled with formaline, lobac P, Menno-Ter-forte and sodium hypochlorite. lobac P, formaline, Menno-Ter-forte, Taloset and Virkon S were the most effective disinfectants against club rot (Plasmodiophora hrassicae. Washing under running water was not sufficient to eradicate club rot. Against Rhizoctonia -induced damping off of cauliflower the most effective disinfectants were formaline and Virkon S.

Activity of disinfectants against foodborne pathogens in suspension and adhered to stainless steel surfaces

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Tatiane Karen Cabeça

2012-09-01

Full Text Available The purpose of this study was to investigate and compare the efficacy of various disinfectants on planktonic cells and biofilm cells of Listeria monocytogenes, Staphylococcus aureus and Escherichia coli. Numbers of viable biofilm cells decreased after treatment with all tested disinfectants (iodine, biguanide, quaternary ammonium compounds, peracetic acid and sodium hypochlorite. Sodium hypochlorite was the most effective disinfectant against biofilm cells, while biguanide was the least effective. Scanning electron microscopy observations revealed that cells adhered on stainless steel surface after treatment with the disinfectants. No viable planktonic cells were observed after treatment with the same disinfectants. Based on our findings, we concluded that biofilm cells might be more resistant to disinfectants than plancktonic cells.

Combining Mass Spectrometry and Toxicology for a Multi-Country European Epidemiologic Study on Drinking Water Disinfection By-Products

Science.gov (United States)

The HiWATE (Health Impacts of long-term exposure to disinfection by-products in drinking WATEr) project is the first systematic analysis that combines the epidemiology on adverse pregnancy outcomes with analytical chemistry and analytical biology in the European Union. This study...

Role of ultraviolet (UV) disinfection in infection control and environmental cleaning.

Science.gov (United States)

Qureshi, Zubair; Yassin, Mohamed H

2013-06-01

Ultraviolet (UV) radiation is capable of disinfecting surfaces, water and air. The UV technology was used for many years. However, safer and more effective delivery systems of UV radiation, make it a very useful option for disinfection. Effective disinfection of environmental surfaces is a key step in the prevention of spread of infectious agents. The traditional manual cleaning is essential in assuring adequate elimination of contamination. However, terminal cleaning is frequently suboptimal or unpredictable in many circumstances. UV-C radiation is an adjunctive disinfectant new technology that could kill a wide array of microorganisms including both vegetative and spore forming pathogens. The technology is getting more affordable and has produced consistent reproducible significant reduction of bacterial contamination.

The Effect of Disinfection by Spray Atomization on Dimensional Accuracy of Condensation Silicone Impressions

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Fariba Saleh Saber

2010-12-01

Full Text Available Background and aims. The condensation silicone impression materials are available, but there is little knowledge of their accuracy after disinfection. The objective of this study was to evaluate the effect of the disinfection by spray atomization on dimensional accuracy of condensation silicone impressions. Materials and methods. Impressions were made on a stainless steel master model containing a simulated two complete crown preparation with an edentulous space interposed using Spidex® and Rapid® impression materials. 44 impressions were made with each material, of which 16 were disinfected with 5.25% sodium hypochlorite, 16 were disinfected with 10% iodophor and 12 were not disinfected. Three dimensional measurements of working casts, including interpreparation distance, height, and diameter, were calculated using a measuring microscope graduated at 0.001 mm. Dimensional changes (mm between the disinfected and non-disinfected working casts were compared. One-way analysis of variance (ANOVA was employed to analyze the data (α=0.05. Results. Disinfection of each condensation silicone material by spraying atomization with two different disinfectant material resulted in significant change in interpreparation distance (p<0.05. Changes in height and diameter were only significant in Spidex® impressions (p<0.05. Conclusion. Significant changes in the mean dimensions were seen as a result of disinfection by spraying; however, the dimensional changes do not seem great enough to cause critical positional distortion of teeth when fixed partial denture restorations are made.

[Importance of cleaning and disinfection of critical surfaces in dental health services. Impact of an intervention program].

Science.gov (United States)

Véliz, Elena; Vergara, Teresa; Pearcy, Mercedes; Dabanch, Jeannette

Introduction Dental care has become a challenge for healthcare associated infection prevention programs, since the environment, within other factors, plays an important role in the transmission chain. Materials and Methods An intervention program was designed for the Dental Unit of Hospital Militar de Santiago, between years 2014 and 2015. The program contemplated 3 stages: diagnostic, intervention and evaluation stage. Objective To improve the safety of critical surfaces involved in dental healthcare. Results During the diagnostic stage, the cleaning and disinfection process was found to be deficient. The most contaminated critical surface was the instrument holder unit, then the clean area and lamp handle. The surfaces that significantly reduced their contamination, after the intervention, were the clean area and the instrument carrier unit. Conclusion Training in the processes of cleaning and disinfecting surfaces and dental equipment is one of the cost-effective strategies in preventing healthcare-associated infections (HCAI), with simple and easy-to-apply methods.

Viral Aggregation: Impact on Virus Behavior in the Environment.

Science.gov (United States)

Gerba, Charles P; Betancourt, Walter Q

2017-07-05

Aggregates of viruses can have a significant impact on quantification and behavior of viruses in the environment. Viral aggregates may be formed in numerous ways. Viruses may form crystal like structures and aggregates in the host cell during replication or may form due to changes in environmental conditions after virus particles are released from the host cells. Aggregates tend to form near the isoelectric point of the virus, under the influence of certain salts and salt concentrations in solution, cationic polymers, and suspended organic matter. The given conditions under which aggregates form in the environment are highly dependent on the type of virus, type of salts in solution (cation, anion. monovalent, divalent) and pH. However, virus type greatly influences the conditions when aggregation/disaggregation will occur, making predictions difficult under any given set of water quality conditions. Most studies have shown that viral aggregates increase the survival of viruses in the environment and resistance to disinfectants, especially with more reactive disinfectants. The presence of viral aggregates may also result in overestimation of removal by filtration processes. Virus aggregation-disaggregation is a complex process and predicting the behavior of any individual virus is difficult under a given set of environmental circumstances without actual experimental data.

Disinfection of herbal spa pool using combined chlorine dioxide and sodium hypochlorite treatment.

Science.gov (United States)

Hsu, Ching-Shan; Huang, Da-Ji

2015-02-01

The presence of pathogenic microorganisms in public spa pools poses a serious threat to human health. The problem is particularly acute in herbal spas, in which the herbs and microorganisms may interact and produce undesirable consequences. Accordingly, the present study investigated the effectiveness of a combined disinfectant containing chlorine dioxide and sodium hypochlorite in improving the water quality of a public herbal spa in Taiwan. Water samples were collected from the spa pool and laboratory tests were then performed to measure the variation over time of the microorganism content (total CFU and total coliforms) and residual disinfectant content given a single disinfection mode (SDM) with disinfectant concentrations of 5.2 × 10, 6.29 × 10, 7.4 × 10, and 11.4 × 10(-5) N, respectively. Utilizing the experience gained from the laboratory tests, a further series of on-site investigations was performed using three different disinfection modes, namely SDM, 3DM (once every 3 h disinfection mode), and 2DM (once every 2 h disinfection mode). The laboratory results showed that for all four disinfectant concentrations, the CFU concentration reduced for the first 6 h following SDM treatment, but then increased. Moreover, the ANOVA results showed that the sample treated with the highest disinfectant concentration (11.4 × 10(-5) N) exhibited the lowest rate of increase in the CFU concentration. In addition, the on-site test results showed that 3DM and 2DM treatments with disinfectant concentrations in excess of 9.3 × 10 and 5.5 × 10(-5) N, respectively, provided an effective reduction in the total CFU concentration. In conclusion, the experimental results presented in this study provide a useful source of reference for spa businesses seeking to improve the water quality of their spa pools.

Virucidal efficacy of peracetic acid for instrument disinfection.

Science.gov (United States)

Becker, Britta; Brill, Florian H H; Todt, Daniel; Steinmann, Eike; Lenz, Johannes; Paulmann, Dajana; Bischoff, Birte; Steinmann, Jochen

2017-01-01

Various peracetic-acid (PAA)-based products for processing flexible endoscopes on the market are often based on a two-component system including a cleaning step before the addition of PAA as disinfectant. The peracetic acid concentrations in these formulations from different manufacturers are ranging from 400 to 1500 ppm (part per million). These products are used at temperatures between 20 °C and 37 °C. Since information on the virus-inactivating properties of peracetic acid at different concentrations and temperature is missing, it was the aim of the study to evaluate peracetic acid solutions against test viruses using the quantitative suspension test, EN 14476. In addition, further studies were performed with the recently established European pre norm (prEN 17111:2017) describing a carrier assay for simulating practical conditions using frosted glass. In the first step of examination, different PAA solutions between 400 and 1500 ppm were tested at 20 °C, 25 °C, and 35 °C with three test viruses (adenovirus, murine norovirus and poliovirus) necessary for creating a virucidal action according to the European Norm, EN 14476. A second step for simulating practical conditions based on prEN 17111:2017 followed by spreading a test virus together with soil load onto a glass carrier which was immerged into a peracetic acid solution. A fixed exposure time of five minutes was used in all experiments. In the quantitative suspension test 1500 ppm PAA solution was needed at 35 °C for five minutes for the inactivation of poliovirus, whereas only 400 ppm at 20 °C for adeno- and murine norovirus were necessary. In the carrier assay 400 ppm peracetic acid at 20 °C were sufficient for adenovirus inactivation, whereas 600 ppm PAA were needed at 25 °C and 35 °C and 1000 ppm at 20 °C for murine norovirus. A PAA solution with 1000 ppm at 35 °C was required for complete inactivation of poliovirus. However, a dramatically decrease of titer after the

Determination of decimal reduction time (D value) of chemical agents used in hospitals for disinfection purposes

Science.gov (United States)

Mazzola, Priscila Gava; Penna, Thereza Christina Vessoni; da S Martins, Alzira M

2003-01-01

Background Prior to the selection of disinfectants for low, intermediate and high (sterilizing) levels, the decimal reduction time, D-value, for the most common and persistent bacteria identified at a health care facility should be determined. Methods The D-value was determined by inoculating 100 mL of disinfecting solution with 1 mL of a bacterial suspension (104 – 105 CFU/mL for vegetative and spore forms). At regular intervals, 1 mL aliquots of this mixture were transferred to 8 mL of growth media containing a neutralizing agent, and incubated at optimal conditions for the microorganism. Results The highest D-values for various bacteria were determined for the following solutions: (i) 0.1% sodium dichloroisocyanurate (pH 7.0) – E. coli and A. calcoaceticus (D = 5.9 min); (ii) sodium hypochlorite (pH 7.0) at 0.025% for B. stearothermophilus (D = 24 min), E. coli and E. cloacae (D = 7.5 min); at 0.05% for B. stearothermophilus (D = 9.4 min) and E. coli (D = 6.1 min) and 0.1% for B. stearothermophilus (D = 3.5 min) and B. subtilis (D = 3.2 min); (iii) 2.0% glutaraldehyde (pH 7.4) – B. stearothermophilus, B. subtilis (D = 25 min) and E. coli (D = 7.1 min); (iv) 0.5% formaldehyde (pH 6.5) – B. subtilis (D = 11.8 min), B. stearothermophilus (D = 10.9 min) and A. calcoaceticus (D = 5.2 min); (v) 2.0% chlorhexidine (pH 6.2) – B. stearothermophilus (D = 9.1 min), and at 0.4% for E. cloacae (D = 8.3 min); (vi) 1.0% Minncare® (peracetic acid and hydrogen peroxide, pH 2.3) – B. stearothermophilus (D = 9.1 min) and E. coli (D = 6.7 min). Conclusions The suspension studies were an indication of the disinfectant efficacy on a surface. The data in this study reflect the formulations used and may vary from product to product. The expected effectiveness from the studied formulations showed that the tested agents can be recommended for surface disinfection as stated in present guidelines and emphasizes the importance and need to develop routine and novel programs to

Determination of decimal reduction time (D value of chemical agents used in hospitals for disinfection purposes

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da S Martins Alzira M

2003-10-01

Full Text Available Abstract Background Prior to the selection of disinfectants for low, intermediate and high (sterilizing levels, the decimal reduction time, D-value, for the most common and persistent bacteria identified at a health care facility should be determined. Methods The D-value was determined by inoculating 100 mL of disinfecting solution with 1 mL of a bacterial suspension (104 – 105 CFU/mL for vegetative and spore forms. At regular intervals, 1 mL aliquots of this mixture were transferred to 8 mL of growth media containing a neutralizing agent, and incubated at optimal conditions for the microorganism. Results The highest D-values for various bacteria were determined for the following solutions: (i 0.1% sodium dichloroisocyanurate (pH 7.0 – E. coli and A. calcoaceticus (D = 5.9 min; (ii sodium hypochlorite (pH 7.0 at 0.025% for B. stearothermophilus (D = 24 min, E. coli and E. cloacae (D = 7.5 min; at 0.05% for B. stearothermophilus (D = 9.4 min and E. coli (D = 6.1 min and 0.1% for B. stearothermophilus (D = 3.5 min and B. subtilis (D = 3.2 min; (iii 2.0% glutaraldehyde (pH 7.4 – B. stearothermophilus, B. subtilis (D = 25 min and E. coli (D = 7.1 min; (iv 0.5% formaldehyde (pH 6.5 – B. subtilis (D = 11.8 min, B. stearothermophilus (D = 10.9 min and A. calcoaceticus (D = 5.2 min; (v 2.0% chlorhexidine (pH 6.2 – B. stearothermophilus (D = 9.1 min, and at 0.4% for E. cloacae (D = 8.3 min; (vi 1.0% Minncare® (peracetic acid and hydrogen peroxide, pH 2.3 – B. stearothermophilus (D = 9.1 min and E. coli (D = 6.7 min. Conclusions The suspension studies were an indication of the disinfectant efficacy on a surface. The data in this study reflect the formulations used and may vary from product to product. The expected effectiveness from the studied formulations showed that the tested agents can be recommended for surface disinfection as stated in present guidelines and emphasizes the importance and need to develop routine and novel programs to

Disinfection of bacterial biofilms in pilot-scale cooling tower systems.

Science.gov (United States)

Liu, Yang; Zhang, Wei; Sileika, Tadas; Warta, Richard; Cianciotto, Nicholas P; Packman, Aaron I

2011-04-01

The impact of continuous chlorination and periodic glutaraldehyde treatment on planktonic and biofilm microbial communities was evaluated in pilot-scale cooling towers operated continuously for 3 months. The system was operated at a flow rate of 10,080 l day(-1). Experiments were performed with a well-defined microbial consortium containing three heterotrophic bacteria: Pseudomonas aeruginosa, Klebsiella pneumoniae and Flavobacterium sp. The persistence of each species was monitored in the recirculating cooling water loop and in biofilms on steel and PVC coupons in the cooling tower basin. The observed bacterial colonization in cooling towers did not follow trends in growth rates observed under batch conditions and, instead, reflected differences in the ability of each organism to remain attached and form biofilms under the high-through flow conditions in cooling towers. Flavobacterium was the dominant organism in the community, while P. aeruginosa and K. pneumoniae did not attach well to either PVC or steel coupons in cooling towers and were not able to persist in biofilms. As a result, the much greater ability of Flavobacterium to adhere to surfaces protected it from disinfection, whereas P. aeruginosa and K. pneumoniae were subject to rapid disinfection in the planktonic state.

Peracetic Acid as a Green Disinfectant for Combined Sewer Overflows

Science.gov (United States)

This cooperative research and development agreement between U.S. EPA, Solvay, MSDGC, and CB&I is evaluating the potential of PAA for disinfection of Muddy Creek CSO wastewater and comparing that with sodium hypochlorite disinfection. This presentation will document the effectiven...

High-Rate Disinfection Techniques for Combined Sewer Overflow (Proceedings Paper)

Science.gov (United States)

This paper presents high-rate disinfection technologies for combined sewer overflow (CSO). The high-rate disinfection technologies of interest are: chlorination/dechlorination, ultraviolet light irradiation (UV), chlorine dioxide (ClO2 ), ozone (O3), peracetic acid (CH3COOOH ), a...

Practical considerations in the use of UV light for drinking water disinfection

International Nuclear Information System (INIS)

Jeyanayagam, S.; Cotton, C.

2002-01-01

Ultraviolet (UV) light was discovered approximately 150 years ago. The first commercial UV lamp was made in the early 1900s soon followed by the manufacture of the quartz sleeve. These technological advances allowed the first application of UV light for water disinfection in 1907 in France. In the mid 1980s, UV disinfection was named as a Best available technology (BAT) for wastewater disinfection in the United States. Fueled by the recent findings that UV disinfection can inactivate key pathogens at cost effective UV doses, the drinking water industry in North America is closely investigating its application in large installations. (author)

Spiral-shaped reactor for water disinfection

KAUST Repository

Soukane, Sofiane

2016-04-20

Chlorine-based processes are still widely used for water disinfection. The disinfection process for municipal water consumption is usually carried out in large tanks, specifically designed to verify several hydraulic and disinfection criteria. The hydrodynamic behavior of contact tanks of different shapes, each with an approximate total volume of 50,000 m3, was analyzed by solving turbulent momentum transport equations with a computational fluid dynamics code, namely ANSYS fluent. Numerical experiments of a tracer pulse were performed for each design to generate flow through curves and investigate species residence time distribution for different inlet flow rates, ranging from 3 to 12 m3 s−1. A new nature-inspired Conch tank design whose shape follows an Archimedean spiral was then developed. The spiral design is shown to strongly outperform the other tanks’ designs for all the selected plug flow criteria with an enhancement in efficiency, less short circuiting, and an order of magnitude improvement in mixing and dispersion. Moreover, following the intensification philosophy, after 50% reduction in its size, the new design retains its properties and still gives far better results than the classical shapes.

Plant stress activated by chlorine from disinfectants prepared on the base of sodium hypochlorite

Directory of Open Access Journals (Sweden)

Fargašová Agáta

2017-12-01

Full Text Available In this study, the phytotoxicity of disinfectants prepared on the base of sodium hypochlorite was determined. For our tests two commercial products, Savo and Dom Amor, as well as 10% NaClO solution were used. While Savo contained only NaClO, Dom Amor contained NaClO and earthworm enzymes. Products on the base of NaClO are used in households for cleaning and disinfection of floors, furniture, sanitary and kitchen equipment. Savo may be used for the disinfection of drinking waters as well. Products with NaClO are also used for bacteria, algae and pathogens reduction in irrigation waters. As a subject, young seedlings of mustard Sinapis alba L. were used for the study of chronic toxicity. The observed parameters of the inhibition of roots and shoots growth, dry (DM and fresh (FM mass as well as photosynthetic pigments production (chlorophyll a, b, carotenoids and water content in the plants were determined. The results point out that Dom Amor was the most toxic for S. alba seedlings growth and the rank order of the FAC contents for both plant parts was arranged as: Dom Amor > Savo > NaClO. All disinfectants reduced the DM and FM of roots; however, they stimulated biomass production in the shoots. On the basis of the obtained results it could be concluded, that disinfectants stimulated photosynthetic pigments production and reduced water content mainly in the roots. Dom Amor did not significantly reduced the water content in the shoots and for this parameter the following rank orders of inhibition for roots and shoots could be arranged as NaClO > Dom Amor > Savo and NaClO > Savo > Dom Amor, respectively. All commercial products increased chlorophyll a (Chla and the carotenoids (Car content in the shoots. As significant increase was confirmed first for Chla whose content in the presence of NaClO at concentration 24 mL/L overextended that in the control by 3.5 times. The rank orders of stimulation for Chla and Car were NaClO > Savo > Dom Amor and Dom

Efficacy of cleaning and disinfection procedures in a zebrafish (Danio rerio) facility.

Science.gov (United States)

Garcia, Rachel L; Sanders, George E

2011-11-01

Appropriate cleaning and disinfection procedures in zebrafish (Danio rerio) laboratories are crucial in preventing the spread of aquatic animal pathogens and minimizing the build-up of waste products and biologic matter. The procedures selected should accomplish these goals and incorporate the individual needs of various laboratories. In this study of a single zebrafish facility, we assessed the efficacy of 2 different cleaning and disinfection procedures for nets, tanks, and lids. ATP levels were used as a surrogate biomarker for microbial burden. We measured the number of relative light units (RLU), as an expression of the amount of ATP present, on items before and after disinfection and calculated the percentage reduction. We compared daily replacement of a commercial net disinfection product in J lab with weekly replacement in H lab and found a 96.6% reduction in RLU in H lab and a 91.2% reduction in J lab. These results indicate that either replacement schedule is effective. Evaluation of tanks and lids soaked in a bleach disinfection bath for 30 or 60 min revealed a 99.7% reduction in RLU at 30 min compared with 97.1% at 60 min. Therefore a 30-min soak in a bleach bath achieved a similar level of disinfection as did a 60-min soak. The current results demonstrate that these cleaning and disinfection methods are efficacious.

Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray (Final Report)

Science.gov (United States)

EPA announced the release of the final report, Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray. This report represents a case study of engineered nanoscale silver (nano-Ag), focusing on the specific example of nano-Ag as possibly used in disinfectant spr...

Endoscope disinfection and its pitfalls - requirement for retrograde surveillance cultures

NARCIS (Netherlands)

Buss, A. J.; Been, M. H.; Borgers, R. P.; Stokroos, I.; Melchers, W. J. G.; Peters, F. T. M.; Limburg, A. J.; Degener, J. E.

Background and study aims: Several endoscopy-related outbreaks of infection have been reported in recent years. For early recognition of inadequate disinfection of endoscopes we designed a microbiological surveillance system to evaluate the efficacy of the cleaning and disinfection procedure, and to

Endoscope disinfection and its pitfalls--requirement for retrograde surveillance cultures.

NARCIS (Netherlands)

Buss, A.J.; Been, M.H.; Borgers, R.P.; Stokroos, I.; Melchers, W.J.G.; Peters, F.T.; Limburg, A.J.; Degener, J.E.

2008-01-01

BACKGROUND AND STUDY AIMS: Several endoscopy-related outbreaks of infection have been reported in recent years. For early recognition of inadequate disinfection of endoscopes we designed a microbiological surveillance system to evaluate the efficacy of the cleaning and disinfection procedure, and to

A protocol for evaluation of the role of disinfectants in limiting pathogens and weed moulds in commercial mushroom production.

Science.gov (United States)

Abosriwil, Salem O; Clancy, Kevin J

2002-03-01

In vitro and in vivo evaluations of the effects of three commercial disinfectants on isolates of Trichoderma harzianum Rifai and Cladobotryum dendroides (Bull) W Gams & Hoozemans were combined in the development of methodologies for realistic assessment of disinfectant performance. 'Environ' and 'Purogene' incorporated into agar media at 50 mg AI litre-1 were effective in totally preventing the mycelial growth of T harzianum and C dendroides isolates, whereas with 'Sudol' a concentration of 500 mg AI litre-1 was required. Evaluation of a model in vivo system was combined with observations on the fungicidal effects of disinfectants. Spore suspensions of T harzianum (Th1), T harzianum (Th2) and C dendroides prepared from culture washings with sterilised distilled water were used as contaminating inoculum. Environ, Sudol and Purogene in aqueous solutions at 1000 mg AI litre-1 were sprayed onto these building structure surfaces before or after artificial contamination with spore suspensions. Re-isolation from surfaces was carried out using agar swabs, which were prepared in visking tubing, applied to treated surfaces and incubated at 25 degrees C for 24, 48, 72 or 96 h. Environ and Purogene were more effective than Sudol in limiting the recovery of Trichoderma spp and C dendroides. All three disinfectants applied 12 h after artificial contamination onto wood, concrete or glazed surfaces were able to reduce the recovery of these isolates more effectively than when they were applied 12 h before artificial contamination. Greater persistence of contamination was noted on the rougher surfaces (wood and concrete) than on the smoother glazed surface. It was concluded in this in vivo evaluation that, in many cases, the protection achieved by the physical nature of the smooth glazed tile surfaces was equivalent to that available from the application of disinfectants, thus highlighting the attention needed to the nature of building surfaces in the structures used in the mushroom

Theoretical model for the UV disinfection system in the operating ward of PZU 'Filip Vtori'

International Nuclear Information System (INIS)

Ilkov, Marjan

2010-01-01

Here we investigate the theoretical modeling of an UV disinfection system for the operating ward in PZU 'FILIP VTORI'. As nocosomial infections pose a serious threat to patients everywhere in the world, here the disinfection of the air and the surfaces is modeled and discussed. The surfaces are disinfected with direct illumination of open UV after hours system, UV curtains, overhead disinfection, floor disinfection and disinfection of the incoming air through the ventilation/air-condition system. From the results it can be seen that the concentrations of bacteria, fungi and viruses drop significantly which in turn should give a significant drop in a number of hospital acquired infections.(Author)

Disinfection Pilot Trial for Little Miami WWTP | Science ...

Science.gov (United States)

There is a serious interest growing nationally towards the use of PAA at various stages of public waste water treatment facilities; one of such use is secondary waste water treatment. MSDGC is currently interested in improving efficiency and economic aspects of waste water treatment. MSDGC requested for ORD’s support to evaluate alternative cost-effective disinfectants. This report herein is based on the data generated from the field pilot test conducted at the Little Miami Wastewater Treatment Plant. Chlorine assisted disinfection of wastewaters created the concern regarding the formation of high levels of toxic halogenated disinfection byproducts (DBPs) detrimental to aquatic life and public health. Peracetic acid is emerging as a green alternative to chlorine and claimed to have economic and social benefits. In addition, it is a relatively simple retrofit to the existing chlorine treated wastewater treatment facilities. PAA is appealed to possess a much lower aquatic toxicity profile than chlorine and decays rapidly in the environment, even if overdosed. As a result, PAA generally does not need a quenching step, such as dechlorination, reducing process complexity, sodium pollution and cost. PAA treatment does not result in the formation of chlorinated disinfection by-products such as trihalomethanes (THMs), haloacetic acids and other byproducts such as cyanide and n-Nitrosodimethylamine (NDMA).

Copper disinfection ban causes storm.

Science.gov (United States)

Lester, Alan

2013-05-01

Since 1 February this year, under the EU's Biocidal Products Directive, it has been illegal to sell or use water treatment systems that use elemental copper, a practice employed historically by a significant number of UK healthcare facilities to combat Legionella. Alan Lester, managing director of specialist supplier of 'environmentally-friendly' water treatment systems, Advanced Hydro, says the ban has caused 'a storm of giant proportion,' with advocates of copper ion-based treatment systems arguing that this disinfection method dates back 3,000 years to Egyptian times, making it an 'undoubtedly proven' technology. Here he explains why the ban came into force, considers why the UK's Health and Safety Executive (HSE) is seeking a derogation, looks at the ban's likely impact, and gives a personal viewpoint on the 'pros and cons' of some of the alternative treatment technologies, including a titanium dioxide-based system marketed by Advanced Hydro itself in the UK.

MUTAGENICITY AND DISINFECTION BY-PRODUCTS IN SURFACE DRINKING WATER DISINFECTED WITH PERACETIC ACID

Science.gov (United States)

The aims of this research were to study the influence of peracetic acid (PAA) on the formation of mutagens in surface waters used for human consumption and to assess its potential application for the disinfection of drinking water. The results obtained using PAA were compared to ...

Ultraviolet air disinfection for protection against influenza

International Nuclear Information System (INIS)

Riley, R.L.

1977-01-01

Three converging lines of evidence support the belief that it may be possible, under appropriate circumstances, to interrupt the airborne transmission of influenza by ultraviolet (UV) air disinfection. These lines of evidence are: (a) that influenza is airborne; (b) that UV irradiation of the upper air of a room can provide safe and effective disinfection of air in the lower part of the room; and (c) that epidemic spread of airborne viral infections in humans can be prevented if the population under consideration remains in the UV-protected environment

Possibility of environmentally-safe casing soil disinfection for control of cobwebdisease of button mushroom

Directory of Open Access Journals (Sweden)

Ivana Potočnik

2014-12-01

Full Text Available The soil-borne pathogen Cladobotryum dendroides causes cobweb disease of button mushroom (Agaricus bisporus and its significant yield losses. Casing soil disinfection by toxic formaldehyde is a widespread practice. The aim of this study was to investigate the potential of two environmentally friendly substances, colloidal silver and peracetic acid, against C. dendroides. Their biological efficacy (impact on mushroom yield, effectiveness (disease control and type of interactions between them and the fungicide prochloraz-manganese were evaluated. Black peat/lime casing soil was applied to a colonized substrate with the white button mushroom strain 737, then inoculated with C. dendroides and treated with the fungicide prochloraz-manganse and two environmentally friendly disinfectants based on peracetic acid and colloidal silver. The effects of fungicides on mushroom productivity were evaluated as biological efficacy and calculated as a ratio of fresh weight of total mushroom yield to the weight of dry substrate. Fungicide effectiveness and synergy factor were calculated by Abbott’s (1925 formula. Tests for synergism between prochloraz-manganese and both other substances were performed using Limpel’s formula. The highest biolgical efficacy, exceeding 92.00, was achieved in treatments with prochlorazmanganese, applied alone or in combination with both other disinfectants. The highest effectiveness of 93.33% was attained in treatments with peracetic acid combined with prochloraz-manganese. Trials against cobweb disease revealed a synergistic reaction between the fungicide and peracetic acid and antagonistic between the fungicide and colloidal silver. Peracetic acid provided better disease control, compared to colloidal silver applied alone or in combination with the fungicide. Based on these findings, peracetic acid should be recomended as an environmentally friendly casing soil disinfectant against cobweb disease of A. bisporus.

Comparative evaluation of dimensional stability of impression materials from developing countries and developed countries after disinfection with different immersion disinfectant systems and ultraviolet chamber

Directory of Open Access Journals (Sweden)

Rupandeep Kaur Samra

2018-04-01

Full Text Available Objectives: It was to analyse and compare the effect of different disinfectant systems on the dimensional stability of commonly used irreversible hydrocolloid and addition silicone impression materials from developing countries as compared to materials from developed countries. Material and methods: Disinfectant systems used were glutaraldehyde, sodium hypochlorite and ultraviolet chamber. The stability after disinfection of commonly used alginate and addition silicone of native origin (Algin-Gum & Ad-Sil was compared with similar impression materials from developed countries (Vignette and Aquasil and results compared. A CAD/CAM manufactured stainless steel die simulating maxilla with four metal studs at canine and molar region was used. Impressions were made and disinfected after rinsing and drying and casts poured. The cross arch distance, interabutment distance and the occluso-gingival length of the studs was measured under traveling microscope and observations were recorded and compared. ANOVA test and Bonferroni test was applied. Results: An increase in the interabutment and cross arch distance and decrease in occluso-gingival height was seen in the casts obtained. Glutaraldehyde immersion showed variation in the interabutment and cross arch distance for all materials studied. Ultraviolet chamber and sodium hypochlorite produced best results. Dimensional stability of impression materials like Vignette, Algin-Gum & Aquasil was found to within clinically acceptable limits after disinfection while maximum deviation was seen with Algin-Gum. Conclusion: Evaluated materials can be safely disinfected with sodium hypochlorite and ultraviolet chamber. Addition silicone of native origin is at par with impression materials from developed countries but same cannot be said about alginate. Keywords: Dimensional stability, Immersion systems, Ultraviolet chamber, Addition silicone, Alginate, Sodium hypochlorite, Glutaraldehyde

Comparative susceptibility of Salmonella Typhimurium biofilms of different ages to disinfectants.

Science.gov (United States)

Wong, Hui San; Townsend, Kirsty M; Fenwick, Stan G; Maker, Garth; Trengove, Robert D; O'Handley, Ryan M

2010-10-01

There is a general consensus that with increasing age a biofilm shows increased resistance to antimicrobials. In this study the susceptibility of 3-, 5- and 7-day-old Salmonella enterica serovar Typhimurium biofilms to disinfectants was evaluated. It was hypothesized that 7-day-old biofilms would be more resistant to disinfectants compared to 3- and 5-day-old biofilms. Biofilms were formed using the MBEC™ system and treated with six chemical disinfectants for 1 and 5 min. Four disinfectants at the highest concentration available showed 100% reduction in viable cells from all ages of biofilms after exposure for 5 min, and ethanol at 70% v/v was the least effective against biofilms, followed by chlorhexidine gluconate (CG). At the recommended user concentrations, only sodium hypochlorite showed 100% reduction in viable cells from all ages of biofilms. Benzalkonium chloride and CG were the least effective against biofilms, followed by quaternary ammonium compound which only showed 100% reduction in viable cells from 5-day-old biofilms. Overall, the results from this study do not display enhanced resistance in 7-day-old biofilms compared to 3- and 5-day-old biofilms. It is concluded that under the conditions of this study, the age of biofilm did not contribute to resistance towards disinfectants. Rather, the concentration of disinfectant and an increased contact time were both shown to play a role in successful sanitization.

Biomarkers of end of shift exposure to disinfection byproducts in nurses.

Science.gov (United States)

Ioannou, Solomon; Andrianou, Xanthi D; Charisiadis, Pantelis; Makris, Konstantinos C

2017-08-01

Increased disinfectant use commonly takes place in hospitals and other health care settings. A cross-sectional study among active nurses in two Cypriot public hospitals (n=179) was conducted to examine the prevalence of exposure to disinfection byproducts (DBPs), such as trihalomethanes (THMs) using both self-reported information and biomarker measurements. The objectives of this study were to: i) quantify the magnitude and variability of occupational exposure to disinfectants/DBPs in nurses, ii) generate job exposure matrices (JEM) and job task exposure matrices (JTEM) for disinfectants, and iii) assess the major determinants of urinary THMs in nurses. End of shift urinary total THM values showed high variability among the nurses, but did not differ between hospitals. The disinfectant group of alcohols/phenols was used by >98% of nurses, followed by octenidine (82%), iodine and chlorine (39%, each), chlorhexidine (25%), formaldehyde (12%), hydrogen peroxide (11%), and peracetic acid/ammonia/quaternary ammonium compounds (QACs), all being Nurses were exposed to nearly double the levels of TTHMs and BrTHMs (median and IQR, 1027 [560, 2475] ng/g and 323 [212, 497] ng/g, respectively) when compared to those of the general population (552 [309,989] ng/g and 152 [87,261] ng/g, respectively). This was the first occupational health dataset reporting measurements of biomarkers of end of shift exposures to disinfectants/DBPs. Copyright © 2017. Published by Elsevier B.V.

The efficiency of water treatment and disinfection by means of ultraviolet radiation

International Nuclear Information System (INIS)

Sobotka, J.

1993-01-01

Advantages and disadvantages of various water disinfection methods are discussed. The report examines the effectiveness of combined chlorine treatment and UV irradiation method of water disinfection and describes methods of determining UV radiation intensity, α absorption coefficient and radiation dose by means of measuring equipment constructed by the author. The α absorption coefficient dependence on the colour and turbidity of water exposed to radiation is defined. Enchytraeus albidus was applied as bioindicator in UV radiation intensity and disinfection effects measurements. The influence of UV radiation on microbiological, physical, chemical, and toxicological properties of water was determined. Prototype devices for water disinfection with UV radiation were made. (author)

The efficiency of water treatment and disinfection by means of ultraviolet radiation

Energy Technology Data Exchange (ETDEWEB)

Sobotka, J [Medical Academy, Warsaw (Poland). Inst. of Social Medicine

1993-01-01

Advantages and disadvantages of various water disinfection methods are discussed. The report examines the effectiveness of combined chlorine treatment and UV irradiation method of water disinfection and describes methods of determining UV radiation intensity, [alpha] absorption coefficient and radiation dose by means of measuring equipment constructed by the author. The [alpha] absorption coefficient dependence on the colour and turbidity of water exposed to radiation is defined. Enchytraeus albidus was applied as bioindicator in UV radiation intensity and disinfection effects measurements. The influence of UV radiation on microbiological, physical, chemical, and toxicological properties of water was determined. Prototype devices for water disinfection with UV radiation were made. (author).

In-vitro analysis of the microbicidal activity of 6 contact lens care solutions

Directory of Open Access Journals (Sweden)

Hildebrandt Claudia

2012-10-01

Full Text Available Abstract Background Contact lens-related infections are often associated with inadequate contact lens hygiene, and therefore, contact lens care products should be able to sufficiently minimise the amount of pathogens that are responsible for these infections. In 2001, the EN ISO 14729 was introduced to ensure adequate disinfection efficacy of contact lens care solutions, but this norm has recently been criticised. Methods In this study, six frequently used contact lens care solutions were retested according to the Stand Alone Test of the EN ISO 14729 (2001. The Stand Alone Test is a quantitative suspension test. In addition, the products were tested in a modified setting adding an organic load. The load was a mixture of human blood serum, lysozyme, and mucine, which resembles tear fluid. Results The criteria of the Stand Alone Test recommended in EN ISO 14729 were only met by Aosept Plus. This 3% hydrogen-peroxide-based contact lens care solution attained a reduction factor of > 5 log units for bacteria and > 4 for fungi in all cases. Two further contact lens care solutions, Blue Vision and Optifree Replenish, met the criteria of a reduction factor of > 3 log units for bacteria and > 1 log unit for fungi, but only in the presence of artificial tear fluid. The three remaining products did not exhibit adequate disinfecting efficacy, at least against one of the tested microorganisms. Conclusions Through the observation that the artificial tear fluid used in this study influences the disinfecting efficacy of contact lens care solutions, especially that of multi-purpose solutions, in a different way than does albumin, mucine, or even the organic load suggested in EN ISO 14729, it becomes obvious that the test conditions in the EN ISO 14729 should be revised in order to create more realistic conditions, e.g., by using a more realistic artificial tear fluid. Furthermore, we suggest adapting the EN ISO 14729 to the European test hierarchy for chemical

A new UV-LED device for automatic disinfection of stethoscope membranes.

Science.gov (United States)

Messina, Gabriele; Burgassi, Sandra; Messina, Daniele; Montagnani, Valerio; Cevenini, Gabriele

2015-10-01

Stethoscopes are widely used by doctors and nurses. Poor stethoscope hygiene is a potential source of nosocomial infection. This study aimed to propose an innovative solution, based on the latest advances in ultraviolet (UV) light-emitting diodes (LEDs), for disinfecting stethoscope membranes automatically and efficiently. Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Enterococcus faecalis were sown on 28 stethoscope membranes and then transferred to Petri dishes. Treatment involved illuminating exposed Petri dishes with a UVC LED for 1 minute. For each microbe, the number of colony-forming units (cfu) at 36°C was compared in control and treated dishes using the Wilcoxon signed-rank test. The Kruskal-Wallis test was used to assess percent reductions in bacteria. Statistical significance was set at 99%. A significant reduction in cfu counts after UV treatment (P  .01). The stethoscope, symbol of medicine and health care professionals, has been demonstrated to be a carrier of microorganisms. The treatment technique was effective and efficient in disinfecting the membranes. These promising results represent a step forward toward eliminating stethoscope membrane contamination with an innovative approach. Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Possibility of environmentally-safe casing soil disinfection for control of cobweb disease of button mushroom

OpenAIRE

Potočnik Ivana; Rekanović Emil; Stepnović Miloš; Milijašević-Marčić Svetlana; Todorović Biljana; Nikolić-Bujanović Ljiljana; Čekerevac Milan

2014-01-01

The soil-borne pathogen Cladobotryum dendroides causes cobweb disease of button mushroom (Agaricus bisporus) and its significant yield losses. Casing soil disinfection by toxic formaldehyde is a widespread practice. The aim of this study was to investigate the potential of two environmentally friendly substances, colloidal silver and peracetic acid, against C. dendroides. Their biological efficacy (impact on mushroom yield), effectiveness (disease control) ...

Evaluation of 5 cleaning and disinfection methods for nets used to collect zebrafish (Danio rerio).

Science.gov (United States)

Collymore, Chereen; Porelli, Gina; Lieggi, Christine; Lipman, Neil S

2014-11-01

Few standardized methods of cleaning and disinfecting equipment in zebrafish facilities have been published, even though the effectiveness of these procedures is vital to preventing the transmission of pathogenic organisms. Four chemical disinfectants and rinsing with municipal tap water were evaluated for their ability to disinfect nets used to capture zebrafish. The disinfectants included benzalkonium chloride+methylene blue, sodium hypochlorite, chlorine dioxide, and potassium peroxymonosulfate+sodium chloride for a soak time of 5 or 30 min. Disinfection effectiveness was evaluated by using an ATP-based system that measured the reduction in absolute number and percentage of relative light units. In addition, nets were cultured aerobically on blood and MacConkey agar plates to determine the number of bacteria remaining after disinfection procedures. Soaking nets in sodium hypochlorite for 30 min and in potassium peroxymonosulfate+sodium chloride for 5 or 30 min were effective means of disinfection, according to at least 90% reduction in the number of relative light units and no bacterial growth after cleaning. These results will aid facility managers, veterinarians and investigators in selecting net cleaning and disinfection protocols.

TiO{sub 2}-based photocatalytic disinfection of microbes in aqueous media: A review

Energy Technology Data Exchange (ETDEWEB)

Laxma Reddy, P.Venkata [Program in Environmental Science and Engineering, University of Texas El Paso, El Paso, TX 799038 (United States); Kavitha, Beluri [Department of Pharmacology, Kamineni Institute of Medical Sciences, Dr. NTRUHS, Vijayawada, Andhra Pradesh 520008 (India); Kumar Reddy, Police Anil [School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 38541 (Korea, Republic of); Kim, Ki-Hyun, E-mail: kkim61@hanyang.ac.kr [Department of Civil & Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763 (Korea, Republic of)

2017-04-15

The TiO{sub 2} based photocatalyst has great potential for the disinfection/inactivation of harmful pathogens (such as E.coli in aqueous media) along with its well-known usefulness on various chemical pollutants. The disinfection property of TiO{sub 2} is primarily attributed to surface generation of reactive oxygen species (ROS) as well as free metal ions formation. Furthermore, its disinfection capacity and overall performance can be significantly improved through modifications of the TiO{sub 2} material. In this review, we provide a brief survey on the effect of various TiO{sub 2} materials in the disinfection of a wide range of environmentally harmful microbial pathogens (e.g., bacteria, fungi, algae, and viruses) in aqueous media. The influencing factors (such as reactor design, water chemistry, and TiO{sub 2} modifications) of such processes are discussed along with the mechanisms of such disinfection. It is believed that the combined application of disinfection and decontamination will greatly enhance the utilization of TiO{sub 2} photocatalyst as a potential alternative to conventional methods of water purification. - Highlights: • The advent of industrialization jeopardized the quality of drinking water. • TiO{sub 2} photocatalysis holds promise both in the degradation of pollutants and for disinfection. • The applicability of TiO{sub 2}-based decontamination is explored for microbial disinfection. • Here we provide a comprehensive review on titania-based photocatalysts for disinfection.

Determining Exposure Factors of Anti-Fogging, Dye, Disinfectant, Repellent, and Preservative Products in Korea.

Science.gov (United States)

Lee, Daeyeop; Kim, Joo-Hyon; Kim, Taksoo; Yoon, Hyojung; Jo, Areum; Lee, Byeongwoo; Lim, Hyunwoo; Kim, Pilje; Seo, Jungkwan

2018-01-30

Reliable exposure factors are essential to determine health risks posed by chemicals in consumer products. We analyzed five risk-concerned product categories (anti-fogging, dye, disinfectant, repellent, and preservative products) for 13 products (three car anti-fogging products, a lens anti-fogging product, two car dye products, two drain disinfectants, an air conditioner disinfectant, a chlorine-based disinfectant, a fabric repellent, an insect repellent for food, and a wood preservative) considered to be of high risk in order to determine exposure factors via web surveys and estimation of amount of product. Among the 3000 participants (1482 (49%) men) aged ≥19 years, drain disinfectants were used most frequently (38.2%); the rate of usage of the other products ranged between 1.1-24.0%. The usage rates for the consumer products differed by sex, age, income, and education. Some consumer products such as car and lens anti-fogging products, chlorine-based disinfectants, fabric repellents, and drain disinfectants were regularly used more than once a month, while car dye products, air conditioner disinfectants, insect repellents for food, and wood preservatives were not regularly used owing to the specific product purposes and seasonal needs. Our results could be used for managing or controlling chemical substances in consumer products and conducting accurate exposure assessments.

Evaluation of hospital disinfection as a means of controlling endemic ...

African Journals Online (AJOL)

Evaluation of hospital environment disinfection as a means of controlling endemic nosocomial pathogens in a University Teaching Hospital in Nigeria was evaluated. Disinfectant used in the Hospital was collected from the Infection Control unit and prepared in different concentrations. The isolated bacterial species from the ...

Two time-series analyses of the impact of antibiotic consumption and alcohol-based hand disinfection on the incidences of nosocomial methicillin-resistant Staphylococcus aureus infection and Clostridium difficile infection.

Science.gov (United States)

Kaier, Klaus; Hagist, Christian; Frank, Uwe; Conrad, Andreas; Meyer, Elisabeth

2009-04-01

To determine the impact of antibiotic consumption and alcohol-based hand disinfection on the incidences of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection and Clostridium difficile infection (CDI). Two multivariate time-series analyses were performed that used as dependent variables the monthly incidences of nosocomial MRSA infection and CDI at the Freiburg University Medical Center during the period January 2003 through October 2007. The volume of alcohol-based hand rub solution used per month was quantified in liters per 1,000 patient-days. Antibiotic consumption was calculated in terms of the number of defined daily doses per 1,000 patient-days per month. The use of alcohol-based hand rub was found to have a significant impact on the incidence of nosocomial MRSA infection (Phand rub was associated with a lower incidence of nosocomial MRSA infection. Conversely, a higher level of consumption of selected antimicrobial agents was associated with a higher incidence of nosocomial MRSA infection. This analysis showed this relationship was the same for the use of second-generation cephalosporins (P= .023), third-generation cephalosporins (P= .05), fluoroquinolones (P= .01), and lincosamides (P= .05). The multivariate analysis (R2=0.55) showed that a higher level of consumption of third-generation cephalosporins (P= .008), fluoroquinolones (P= .084), and/or macrolides (P= .007) was associated with a higher incidence of CDI. A correlation with use of alcohol-based hand rub was not detected. In 2 multivariate time-series analyses, we were able to show the impact of hand hygiene and antibiotic use on the incidence of nosocomial MRSA infection, but we found no association between hand hygiene and incidence of CDI.

[The principle of registration, evaluation and testing of disinfecting preparations].

Science.gov (United States)

Röhm-Rodowald, Ewa; Jakimiak, Bozenna; Podgórska, Marta

2008-01-01

Disinfectants are used to produce a state in which the number of living micro-organisms has been reduced to a level which is appropriate to the practical situation. For any products which are included in the Biocidal Directive 98/8/EC, for which specific activity is claimed, test data has to be approved by the regulatory authority and a product license obtained before the product can be offered for sale. Disinfectants can be recorded as biocidal products or medical devices. Presently, it is possible to measure the activity of a product on defined micro-organisms in specified experimental conditions. Efficacy is the result of the use of a product according to a defined application. To allow different requirements in different areas of application, separate tests and pass criteria have been or will be prepared for each of following three areas of application: medical, veterinary and group comprising food, industrial, domestic and institutional areas. The laboratory methods to be used for testing the activity of chemical disinfectants meets the European standards. The tests are categorised on a modular basis as follows: phase 1 tests, phase 2 step 1 tests, phase 2 step 2 tests and phase 3 tests. In order to claim that a product has disinfectant properties, suitable for use in the medical area, the product shall be tested according to European standards: phase 2 step 1 tests, phase 2 step 2 tests. Phase 1 tests are not required to support claims for chemical disinfectants used in human medicine. Only phase 1 tests are required to support claims for active substances for which no particular area of application is specified. Medical devices are subjects to the European Directive 93/42/EEC which requires that a product must carry a CE mark. Disinfectants which are intended specifically by its manufacturer to be used on medical devices are themselves medical devices and so these products, as well as conforming to the instrument disinfection European standards as specified

Solar water disinfecting system using compound parabolic concentrating collector

Energy Technology Data Exchange (ETDEWEB)

El-Ghetany, H.H.; Saitoh, T.S. [Tohoku Univ., Sendai (Japan)

2000-05-31

Solar water disinfection is an alternative technology using solar radiation and thermal treatment to inactivate and destroy pathogenic microorganisms present in water. The Compound Parabolic Concentrating, (CPC) collector can be used as an efficient key component for solar disinfectanting system. Two types of the CPC collectors are studied, namely the transparent-tube and the Copper-tube CPC collector. It is found that after 30 minutes of exposing the water sample to solar radiation or heating it up to 65 degree C for a few minuets all the coliform bacterial present in the contaminated water sample were completely eliminated. In this article, the effect of water temperature on the disinfecting process was presented. Thermal and micro-biological measurements were also made to evaluate the system performance. (author)

Ultraviolet light - nature's own disinfection process

Energy Technology Data Exchange (ETDEWEB)

Munkeberg, T [Thorolf Gregersen a/s, Oslo (Norway)

1978-05-18

Ultraviolet radiation from the sun is the means by which natural pollution products, as well as much of the smaller amount of pollution products produced by man, are converted and returned to the cycle of nature. Artificial ultraviolet radiation offers an optimum method for the disinfection of drinking water and can be used in the long term without undesireable effects on man or the enviromment. There is no evidence that ultraviolet irradiation leads to radiation resistant mutations of bacteria. The geometrical arrangement of ultraviolet disinfection units is described and the capacities of typical units is mentioned as being 600-800 m/sup 3/ /hr, though there is no reason why this should not be increased.

Ultraviolet light - nature's own disinfection process

International Nuclear Information System (INIS)

Munkeberg, T.

1978-01-01

Ultraviolet radiation from the sun is the means by which natural pollution products, as well as much of the smaller amount of pollution products produced by man, are converted and returned to the cycle of nature. Artificial ultraviolet radiation offers an optimum method for the disinfection of drinking water and can be used in the long term without undesireable effects on man or the enviromment. There is no evidence that ultraviolet irradiation leads to radiation resistant mutations of bacteria. The geometrical arrangement of ultraviolet disinfection units is described and the capacities of typical units is mentioned as being 600-800 m 3 /hr, though there is no reason why this should not be increased. (JIW)

[Surface disinfection in the context of infection prevention in intensive care units].

Science.gov (United States)

Kossow, A; Schaber, S; Kipp, F

2013-03-01

The highest proportion of nosocomial infections occurs on intensive care units (ICU) and infections with multiresistant pathogens are an ever increasing problem. Preventative measures should consist of a bundle of different measures including measures that address a specific problem and standard hygiene measures that are relevant in all areas. Specific measures in ICUs primarily aim at the prevention of ventilator associated pneumonia, blood vessel catheter associated infections and nosocomial urinary tract infections. Surface disinfection belongs to the standard hygiene measures and plays an inferior role compared to hand hygiene; however, surfaces come into focus in outbreak situations. The Commission on Hospital Hygiene (KRINKO) at the Robert Koch Institute (the German health protection agency) published recommendations regarding the cleaning and disinfection of surfaces. The frequency with which cleaning and/or disinfection is required varies according to defined areas of risk. The frequency and the disinfection agents used are documented in the disinfection plan.

Characterization of Cleaning and Disinfecting Tasks and Product Use Among Hospital Occupations

Science.gov (United States)

Saito, Rena; Virji, M. Abbas; Henneberger, Paul K.; Humann, Michael J.; LeBouf, Ryan F.; Stanton, Marcia L.; Liang, Xiaoming; Stefaniak, Aleksandr B.

2016-01-01

Background Healthcare workers have an elevated prevalence of asthma and related symptoms associated with the use of cleaning/disinfecting products. The objective of this study was to identify and characterize cleaning/disinfecting tasks and products used among hospital occupations. Methods Workers from 14 occupations at five hospitals were monitored for 216 shifts, and work tasks and products used were recorded at five-minute intervals. The major chemical constituents of each product were identified from safety data sheets. Results Cleaning and disinfecting tasks were performed with a high frequency at least once per shift in many occupations. Medical equipment preparers, housekeepers, floor strippers/waxers, and endoscopy technicians spent on average 108–177 min/shift performing cleaning/disinfecting tasks. Many occupations used products containing amines and quaternary ammonium compounds for > 100 min/shift. Conclusions This analysis demonstrates that many occupations besides housekeeping incur exposures to cleaning/disinfecting products, albeit for different durations and using products containing different chemicals. PMID:25351791

Disinfection of stabilization pond effluent by peracetic acid and sodium hypochlorite

Directory of Open Access Journals (Sweden)

Negar Rezania

2013-01-01

Conclusions: The study demonstrated that application of combined PAA and NaOCl in disinfecting the effluent of the stabilization pond will promote the efficiency of disinfection process in inactivating the coliform group bacteria and fecal streptococci.

Antiviral activity of a novel composition of peracetic acid disinfectant on parvoviruses

Science.gov (United States)

Dagher, Fadi; Jiang, Jun; Tijssen, Peter; Laliberté, Jean-François

2017-01-01

Porcine parvoviruses (PPV) are known to be particularly resistant to many disinfectants used to control other non-enveloped viruses. However, effective disinfectants used against PPV are harsh and corrosive to animal health facilities and the environment. We propose a noncorrosive “green” disinfectant that generates peracetic acid in-situ and is capable of inactivating PPV completely at a 1% concentration for a 10-minute contact time. PMID:28154460

Disinfection of bacteria attached to granular activated carbon.

Science.gov (United States)

LeChevallier, M W; Hassenauer, T S; Camper, A K; McFeters, G A

1984-01-01

Heterotrophic plate count bacteria, coliform organisms, and pathogenic microorganisms attached to granular activated carbon particles were examined for their susceptibility to chlorine disinfection. When these bacteria were grown on carbon particles and then disinfected with 2.0 mg of chlorine per liter (1.4 to 1.6 mg of free chlorine residual per liter after 1 h) for 1 h, no significant decrease in viable counts was observed. Washed cells attached to the surface of granular activated carbon particles showed similar resistance to chlorine, but a progressive increase in sublethal injury was found. Observations made by scanning electron microscope indicated that granular activated carbon was colonized by bacteria which grow in cracks and crevices and are coated by an extracellular slime layer. These data suggest a possible mechanism by which treatment and disinfection barriers can be penetrated and pathogenic bacteria may enter drinking water supplies. Images PMID:6508306

Chemical disinfection of combined sewer overflow waters using performic acid or peracetic acids.

Science.gov (United States)

Chhetri, Ravi Kumar; Thornberg, Dines; Berner, Jesper; Gramstad, Robin; Öjstedt, Ulrik; Sharma, Anitha Kumari; Andersen, Henrik Rasmus

2014-08-15

We investigated the possibility of applying performic acid (PFA) and peracetic acid (PAA) for disinfection of combined sewer overflow (CSO) in existing CSO management infrastructures. The disinfection power of PFA and PAA towards Escherichia coli (E. coli) and Enterococcus was studied in batch-scale and pre-field experiments. In the batch-scale experiment, 2.5 mg L(-1) PAA removed approximately 4 log unit of E. coli and Enterococcus from CSO with a 360 min contact time. The removal of E. coli and Enterococcus from CSO was always around or above 3 log units using 2-4 mg L(-1) PFA; with a 20 min contact time in both batch-scale and pre-field experiments. There was no toxicological effect measured by Vibrio fischeri when CSO was disinfected with PFA; a slight toxic effect was observed on CSO disinfected with PAA. When the design for PFA based disinfection was applied to CSO collected from an authentic event, the disinfection efficiencies were confirmed and degradation rates were slightly higher than predicted in simulated CSO. Copyright © 2014 Elsevier B.V. All rights reserved.

TiO2-based photocatalytic disinfection of microbes in aqueous media: A review.

Science.gov (United States)

Laxma Reddy, P Venkata; Kavitha, Beluri; Kumar Reddy, Police Anil; Kim, Ki-Hyun

2017-04-01

The TiO 2 based photocatalyst has great potential for the disinfection/inactivation of harmful pathogens (such as E.coli in aqueous media) along with its well-known usefulness on various chemical pollutants. The disinfection property of TiO 2 is primarily attributed to surface generation of reactive oxygen species (ROS) as well as free metal ions formation. Furthermore, its disinfection capacity and overall performance can be significantly improved through modifications of the TiO 2 material. In this review, we provide a brief survey on the effect of various TiO 2 materials in the disinfection of a wide range of environmentally harmful microbial pathogens (e.g., bacteria, fungi, algae, and viruses) in aqueous media. The influencing factors (such as reactor design, water chemistry, and TiO 2 modifications) of such processes are discussed along with the mechanisms of such disinfection. It is believed that the combined application of disinfection and decontamination will greatly enhance the utilization of TiO 2 photocatalyst as a potential alternative to conventional methods of water purification. Copyright © 2017 Elsevier Inc. All rights reserved.

Residual viral and bacterial contamination of surfaces after cleaning and disinfection

NARCIS (Netherlands)

Tuladhar, E.; Hazeleger, W.C.; Koopmans, M.; Zwietering, M.H.; Beumer, R.R.; Duizer, E.

2012-01-01

Environmental surfaces contaminated with pathogens can be sources of indirect transmission, and cleaning and disinfection are common interventions focused on reducing contamination levels. We determined the efficacy of cleaning and disinfection procedures for reducing contamination by noroviruses,

Study on a New Ultraviolet Sterilizer to the Surface Disinfection of the Ultrasound Probe.

Science.gov (United States)

Chen, Gui Qiu; Chen, Yu Hao; Yi, Liang; Yin, Jin; Gao, Qiong; Song, Jiang Nan; Li, Shi Kang; Chen, Pei Hou; Guo, Gui Ping

2018-02-01

We studied the disinfection effect of a new ultraviolet (UV) sterilizer and its utilization on ultrasound probe surfaces. Carrier quantitative germicidal tests, simulated on-the-spot trials, and organic substance influence tests were used to carry out experimental observation. Artificially infected probes were disinfected using the sterilizer or a germicidal lamp for comparison. The total number and types of bacteria were determined and identified. Our results demonstrated the sterilizer had the best disinfection effect among three different disinfection methods in hospital. The sterilizer has been used in a hospital setting for 2 years with no notable damage to the ultrasound probe instrument. It has the advantages of fast disinfection, high disinfection effect, and good compatibility with the ultrasound instrument, worthy of being a promoted application in medical institutions. Copyright © 2018 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

Synergistic effect of ultrasonic pre-treatment combined with UV irradiation for secondary effluent disinfection.

Science.gov (United States)

Jin, Xin; Li, Zifu; Xie, Lanlan; Zhao, Yuan; Wang, Tingting

2013-11-01

The ultraviolet (UV) disinfection efficiency is often affected by suspended solids (SS). Given their high concentration or large particle size, SS can scatter UV light and provide shielding for bacteria. Thus, ultrasound is often employed as a pre-treatment process to improve UV disinfection. This work investigated the synergistic effect of ultrasound combined with UV for secondary effluent disinfection. Bench-scale experiments were conducted in using samples obtained from secondary sedimentation tanks. These tanks belonged to three wastewater treatment plants in Beijing that use different kinds of biological treatment methods. Several parameters may contribute to the changes in the efficiency of ultrasound and UV disinfection. Thus, the frequency and energy density of ultrasound, as well as the SS, were investigated. Results demonstrated that samples which have relatively higher SS concentrations or higher percentages of larger particles have less disinfection efficiency using UV disinfection alone. However, the presence of ultrasound could improve the disinfection efficiency because it has synergistic effect. Changes in the particle size distribution and SS concentration notably affected the efficiency of UV disinfection. The efficiency of Escherichia coli elimination can be decreased by 1.2 log units as the SS concentration increases from 16.9 mg/l to 25.4 mg/l at a UV energy density of 40 mJ/cm(2). UV disinfection alone reduced the E. coli population by 3.4 log units. However, the synergistic disinfection of ultrasound and UV could reach 5.4 log units during the reduction of E. coli at a 40 kHz frequency and an energy density of 2.64 kJ/l. The additional synergistic effect is 1.1 log units. Copyright © 2013 Elsevier B.V. All rights reserved.

[Assessment of disinfection and sterilization processes in dental practice as an important factors in prevention of infections].

Science.gov (United States)

Podgórska, Marta; Jakimiak, Bozenna; Röhm-Rodowald, Ewa; Chojecka, Agnieszka

2009-01-01

The dental health-care settings is an environment where disease transmission occurs easily. Prevention of cross infection is therefore a crucial aspect of dental practice and dental clinic stuffmust adopt certain basic routines while practicing. Infections may be transmitted in the dental operatory through direct contact with blood, oral fluids or other secretions; via indirect contact with contaminated instruments, equipment or environmental surfaces; or by contact with airborne contaminants present in either droplet splatter or aerosols of oral and respiratory fluids. Strategies to prevent dental patient infections have focused on disinfection and sterilization. This study evaluates basic routines in prevention of cross-infection in the dentistry. The sample comprised 100 dentists, who completed questionnaires. Based on inquires the conditions for disinfection and sterilization of medical devices were assessed. The following issues were taken into consideration: the way of disinfection and preparation of the disinfectants, the localization of disinfection, preparing to disinfection, washing and packing of dental devices, the frequency of disinfection, methods of sterilization and the monitoring system, type of sterilizers and the available cycles. The dental practices are well equiped to proceed the steam sterilization, but 33% of dentists don't know the available cycles in their autoclaves. Only 35% of them made sterilization process protocols. Very common are three failures of instruments disinfections: multiple use of disinfectant, adding of disinfectant, adding new instruments. There is still need for improvement in disinfection and sterilization in dental practice, especially including: monitoring and documentation of sterilization process, proper use of disinfectants according to manufactures instructions, frequent disinfection of surfaces which contact with patients. Dental stuff should take part in advanced training courses about disinfection and

Reducing the chlorine dioxide demand in final disinfection of drinking water treatment plants using activated carbon.

Science.gov (United States)

Sorlini, Sabrina; Biasibetti, Michela; Collivignarelli, Maria Cristina; Crotti, Barbara Marianna

2015-01-01

Chlorine dioxide is one of the most widely employed chemicals in the disinfection process of a drinking water treatment plant (DWTP). The aim of this work was to evaluate the influence of the adsorption process with granular activated carbon (GAC) on the chlorine dioxide consumption in final oxidation/disinfection. A first series of tests was performed at the laboratory scale employing water samples collected at the outlet of the DWTP sand filter of Cremona (Italy). The adsorption process in batch conditions with seven different types of GAC was studied. A second series of tests was performed on water samples collected at the outlet of four GAC columns installed at the outlet of the DWTP sand filter. The results showed that the best chlorine dioxide demand (ClO2-D) reduction yields are equal to 60-80% and are achieved in the first 30 min after ClO2 addition, during the first 16 days of the column operation using a mineral, coal-based, mesoporous GAC. Therefore, this carbon removes organic compounds that are more rapidly reactive with ClO2. Moreover, a good correlation was found between the ClO2-D and UV absorbance at wavelength 254 nm using mineral carbons; therefore, the use of a mineral mesoporous GAC is an effective solution to control the high ClO2-D in the disinfection stage of a DWTP.

Evaluation of two recommended disinfection methods for cleaning cloths used in food services of southern Brazil.

Science.gov (United States)

Bartz, Sabrina; Tondo, Eduardo Cesar

2013-01-01

In the State of Rio Grande do Sul (RS), Southern Brazil, a good manufacturing practices regulation was published recommending two disinfection methods for cleaning cloths used in food services. The aim of the present study was to evaluate the efficacy of those methods. Cleaning cloths were sampled without prior notice at food services, on common working days. For the analyses, the cloths were divided in two sub-samples, being one of them microbiologically analyzed. The second sub-sample was further divided in two pieces and submitted to hand washing for two minutes. After that, one piece was boiled in water for 15 min and the other one was soaked in a 200 ppm sodium hypochlorite solution for 15 min. Both pieces of cloth were submitted to microbiological analyses. Cleaning cloths presented total aerobic mean counts of 6.9 ± 6.7 log/cm(2). All cleaning cloths presented coliform contamination, and 40% demonstrated mean counts of 6.2 ± 5.6 log/cm(2). Presumptive S. aureus mean counts of 5.5 ± 4.9 log/cm(2) were found. No statistic correlation was observed among the number of meals served daily in the food services and the microbiological contamination levels. After washing and disinfection, microbiological counts were significantly (p disinfect cleaning cloths used in food services.

Disinfectant and antibiotic activities: a comparative analysis in Brazilian hospital bacterial isolates

Directory of Open Access Journals (Sweden)

Guimarães Márcia Aparecida

2000-01-01

Full Text Available Nosocomial infections are an important cause of morbidity and mortality all over the world. It has been shown that appropriate environmental hygienic and disinfection practices can be very helpful to hospital infection control. The purpose of this study was to evaluate the bactericidal activity of some disinfectants against antibiotic-susceptible and antibiotic-resistant hospital bacterial isolates. The susceptibility of 27 clinical isolates to disinfectants and antibiotics was determined by the Association of Official Analytical Chemist?s (AOAC Use-Dilution method and by the Kirby-Bauer method, respectively. All strains tested were susceptible to sodium hypochlorite, glutaraldehyde and to the association quaternary ammonium - formaldehyde - ethyl alcohol disinfectants. However, the susceptibility of strains to phenol and to one quaternary ammonium compound was variable. Among twenty-one antibiotic-multiresistant strains (methicillin-resistant staphylococci, Enterococcus spp, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Serratia marcescens and Escherichia coli eleven (52% and eight (38% strains were resistant to the quaternary ammonium and phenol compounds, respectively. Among six isolates that demonstrated susceptibility to antibiotics (staphylococci, Enterococcus spp, P. mirabilis, E. cloacae and E. coli two strains (33% showed resistance to these disinfectants. The results demonstrated the lack of correlation between antibiotic-susceptibility and susceptibility to disinfectants in hospital strains.

Disinfection studies of Nahar (Mesua ferrea) seed kernel oil using ...

African Journals Online (AJOL)

GREGORY

2011-12-16

Dec 16, 2011 ... with a k value of -0.040. Key words: Nahar (Mesua ferrea) seed kernel oil, extraction, gum Arabic, disinfection, kinetics. INTRODUCTION. Disinfection plays a key role in the reclamation and reuse of wastewater for eliminating infectious diseases, this, in part, augments domestic water supply and decreases ...

Disinfection of wastewater with peracetic acid: a review.

Science.gov (United States)

Kitis, Mehmet

2004-03-01

Peracetic acid is a strong disinfectant with a wide spectrum of antimicrobial activity. Due to its bactericidal, virucidal, fungicidal, and sporicidal effectiveness as demonstrated in various industries, the use of peracetic acid as a disinfectant for wastewater effluents has been drawing more attention in recent years. The desirable attributes of peracetic acid for wastewater disinfection are the ease of implementing treatment (without the need for expensive capital investment), broad spectrum of activity even in the presence of heterogeneous organic matter, absence of persistent toxic or mutagenic residuals or by-products, no quenching requirement (i.e., no dechlorination), small dependence on pH, short contact time, and effectiveness for primary and secondary effluents. Major disadvantages associated with peracetic acid disinfection are the increases of organic content in the effluent due to acetic acid (AA) and thus in the potential microbial regrowth (acetic acid is already present in the mixture and is also formed after peracetic acid decomposition). Another drawback to the use of peracetic acid is its high cost, which is partly due to limited production capacity worldwide. However, if the demand for peracetic acid increases, especially from the wastewater industry, the future mass production capacity might also be increased, thus lowering the cost. In such a case, in addition to having environmental advantages, peracetic acid may also become cost-competitive with chlorine.

[Decontamination of dental unit waterlines using disinfectants and filters].

Science.gov (United States)

Monarca, S; Garusi, G; Gigola, P; Spampinato, L; Zani, C; Sapelli, P L

2002-10-01

Bacterial contamination of the dental unit water system can become a health problem for patients, particularly if they are immunodepressed. The present study has had the purpose of evaluating the effectiveness of methods of chemical decontamination using different disinfectants (peracetic acid, hydrogen peroxide, silver salts, chloramine T, glutaraldehyde T4) and methods of physical decontamination using synthetic membranes for the filtration of water. A preliminary removal procedure of the biofilm present in the waterline has been followed in a dental unit prepared on purpose for the research; subsequently different 2-week long maintenance procedures were applied using disinfectants injected by a pump and finally the bacterial contamination of the water flowing from the waterline was evaluated. The physical decontamination was performed using 0.22 mm membrane filters, which have been installed also in another dental unit, and the filtered water was analyzed to detect bacterial contamination. The preliminary procedure of biofilm removal succeeded obtaining germ-free water. Among the disinfectants used for the maintenance of the water quality only glutaraldehyde T4 was able to reduce the bacterial contamination under the limit suggested by the ADA. The membrane filter system was not able to purify the water, but when a disinfectant (peracetic acid) was used in the last part of the waterline good results were obtained. At present no decontamination system of dental waterline is available, and glutaraldehyde T4 seems to be the best disinfectant only if integrated with periodic biofilm removal for the maintenance of the water quality.

Point-of-use water disinfection using ultraviolet and visible light-emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Lui, Gough Yumu, E-mail: gough@student.unsw.edu.au [UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); School of Photovoltaics and Renewable Energy Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Roser, David, E-mail: djroser@unsw.edu.au [UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Corkish, Richard, E-mail: r.corkish@unsw.edu.au [School of Photovoltaics and Renewable Energy Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Ashbolt, Nicholas J., E-mail: ashbolt@ualberta.ca [UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); School of Public Health, South Academic Building, University of Alberta, Edmonton, Alberta T6G 2G7 (Canada); Stuetz, Richard, E-mail: r.stuetz@unsw.edu.au [UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 (Australia)

2016-05-15

Improvements in point-of-use (POU) drinking water disinfection technologies for remote and regional communities are urgently needed. Conceptually, UV-C light-emitting diodes (LEDs) overcome many drawbacks of low-pressure mercury tube based UV devices, and UV-A or visible light LEDs also show potential. To realistically evaluate the promise of LED disinfection, our study assessed the performance of a model 1.3 L reactor, similar in size to solar disinfection bottles. In all, 12 different commercial or semi-commercial LED arrays (270–740 nm) were compared for their ability to inactivate Escherichia coli K12 ATCC W3110 and Enterococcus faecalis ATCC 19433 over 6 h. Five log{sub 10} and greater reductions were consistently achieved using the 270, 365, 385 and 405 nm arrays. The output of the 310 nm array was insufficient for useful disinfection while 430 and 455 nm performance was marginal (≈ 4.2 and 2.3-log{sub 10}s E. coli and E. faecalis over the 6 h). No significant disinfection was observed with the 525, 590, 623, 660 and 740 nm arrays. Delays in log-phase inactivation of E. coli were observed, particularly with UV-A wavelengths. The radiation doses required for > 3-log{sub 10} reduction of E. coli and E. faecalis differed by 10 fold at 270 nm but only 1.5–2.5 fold at 365–455 nm. Action spectra, consistent with the literature, were observed with both indicators. The design process revealed cost and technical constraints pertaining to LED electrical efficiency, availability and lifetime. We concluded that POU LED disinfection using existing LED technology is already technically possible. UV-C LEDs offer speed and energy demand advantages, while UV-A/violet units are safer. Both approaches still require further costing and engineering development. Our study provides data needed for such work. - Highlights: • Disinfection of E. coli and E. faecalis achieved with 270 and 365–455 nm LEDs • No significant disinfection was found with 310 and > 455 nm LEDs

Point-of-use water disinfection using ultraviolet and visible light-emitting diodes

International Nuclear Information System (INIS)

Lui, Gough Yumu; Roser, David; Corkish, Richard; Ashbolt, Nicholas J.; Stuetz, Richard

2016-01-01

Improvements in point-of-use (POU) drinking water disinfection technologies for remote and regional communities are urgently needed. Conceptually, UV-C light-emitting diodes (LEDs) overcome many drawbacks of low-pressure mercury tube based UV devices, and UV-A or visible light LEDs also show potential. To realistically evaluate the promise of LED disinfection, our study assessed the performance of a model 1.3 L reactor, similar in size to solar disinfection bottles. In all, 12 different commercial or semi-commercial LED arrays (270–740 nm) were compared for their ability to inactivate Escherichia coli K12 ATCC W3110 and Enterococcus faecalis ATCC 19433 over 6 h. Five log_1_0 and greater reductions were consistently achieved using the 270, 365, 385 and 405 nm arrays. The output of the 310 nm array was insufficient for useful disinfection while 430 and 455 nm performance was marginal (≈ 4.2 and 2.3-log_1_0s E. coli and E. faecalis over the 6 h). No significant disinfection was observed with the 525, 590, 623, 660 and 740 nm arrays. Delays in log-phase inactivation of E. coli were observed, particularly with UV-A wavelengths. The radiation doses required for > 3-log_1_0 reduction of E. coli and E. faecalis differed by 10 fold at 270 nm but only 1.5–2.5 fold at 365–455 nm. Action spectra, consistent with the literature, were observed with both indicators. The design process revealed cost and technical constraints pertaining to LED electrical efficiency, availability and lifetime. We concluded that POU LED disinfection using existing LED technology is already technically possible. UV-C LEDs offer speed and energy demand advantages, while UV-A/violet units are safer. Both approaches still require further costing and engineering development. Our study provides data needed for such work. - Highlights: • Disinfection of E. coli and E. faecalis achieved with 270 and 365–455 nm LEDs • No significant disinfection was found with 310 and > 455 nm LEDs. • UV

Regularities of radium coprecipitation with barium sulfate from salt solutions

International Nuclear Information System (INIS)

Kudryavskij, Yu.P.; Rakhimova, O.V.

2007-01-01

Coprecipitation of radium with barium sulfate from highly concentrated NaCl solutions is studied, including the effects of the initial solution composition, alkaline reagent (CaO, NaOH), supporting electrolyte (NaCl) concentration, and pH. The process is promoted by high NaCl concentration in the initial solution, which is due to structural transformation and change in the sorption activity of the BaSO 4 precipitate in salt solutions. The results obtained were applied to recovery of radium from process solutions during the development and introduction of improved procedure for disinfection and decontamination of waste yielded by chlorination of loparite concentrates [ru

Integrated Disinfection By-Products Mixtures Research: Concentration by Reverse Osmosis Membrane Techniques of Disinfection By-Products from Water Disinfected by Chlorination and Ozonation/Postchlorination

Science.gov (United States)

To conduct the health-effect studies described in subsequent articles in this series, concentrated aqueous mixtures of disinfection by-products were required for the two water treatment trains described in the preceding article (Miltner et al., 2008). To accomplish this, the fini...

Acanthamoeba encystment: multifactorial effects of buffers, biocides, and demulcents present in contact lens care solutions

Directory of Open Access Journals (Sweden)

Kovacs CJ

2015-10-01

Full Text Available Christopher J Kovacs, Shawn C Lynch, Marjorie J Rah, Kimberly A Millard, Timothy W Morris Bausch & Lomb Incorporated, Rochester, NY, USA Purpose: To determine whether agents which are purportedly capable of inducing encystment of Acanthamoeba can recapitulate the signal when tested in differing formulations. Methods: In accordance with the International Standard ISO 19045, Acanthamoeba castellanii ATCC 50370 trophozoites were cultured in antibiotic-free axenic medium, treated with test solutions, and encystment rates plus viability were measured via bright field and fluorescent microscopy. Test solutions included phosphate-buffered saline (PBS, borate-buffered saline, biguanide- and hydrogen peroxide (H2O2-based biocides, propylene glycol (PG and povidone (POV ophthalmic demulcents, and one-step H2O2-based contact lens disinfection systems. Results: Only PBS solutions with 0.25 ppm polyaminopropyl biguanide (PAPB and increasing concentrations of PG and POV stimulated A. castellanii encystment in a dose-dependent manner, whereas PBS solutions containing 3% H2O2 and increasing concentrations of PG and POV did not stimulate encystment. Borate-buffered saline and PBS/citrate solutions containing PG also did not stimulate encystment. In addition, no encystment was observed after 24 hours, 7 days, or 14 days of exposures of trophozoites to one-step H2O2 contact lens disinfection products or related solutions. Conclusion: The lack of any encystment observed when trophozoites were treated with existing or new one-step H2O2 contact lens care products, as well as when trophozoites were exposed to various related test solutions, confirms that Acanthamoeba encystment is a complex process which depends upon simultaneous contributions of multiple factors including buffers, biocides, and demulcents. Keywords: propylene glycol, contact lens care system, hydrogen peroxide disinfecting solution

Effect of disinfecting teats post-milking or pre- and post-milking on intramammary infection and somatic cell count.

Science.gov (United States)

Williamson, J H; Lacy-Hulbert, S J

2013-09-01

To determine the effects of (a) post-milking teat disinfection compared with no disinfection and (b) pre- and post-milking teat disinfection compared with post-milking disinfection alone, on the incidence of new intramammary infection (IMI), somatic cell count (SCC) and teat skin abnormalities in dairy cows. In Experiment 1, dairy cows in five dairy herds were randomly allocated to a post-milking teat disinfection group (n=230), that was sprayed with an iodine-based disinfectant (TeatguardPlus) for a complete lactation, or to a non-disinfected group (n=239). In Experiment 2, cows were randomly allocated to post-milking teat disinfection (n=239) or both pre- and post-milking teat disinfection (n=235), using a chloramine-T-based disinfectant (Teatsweet) for both treatments, from calving to 118-127 days in milk. The incidence of new IMI was determined by aseptic sampling of all quarters at calving, during lactation, and at trial end or at drying-off, with clinical mastitis cases sampled on detection. SCC and teat skin abnormalities were measured at 2-monthly intervals during lactation. In both experiments, disinfectant was applied by spray application. Cows that received post-milking teat disinfection had a lower incidence of new IMI caused by Staphylococcus aureus, Streptococcus uberis, Corynebacterium spp and coagulase negative staphylococci, had lower bulk milk SCC during lactation, and had fewer teat skin abnormalities compared with the non-disinfected cows (p disinfection, in addition to post-milking teat disinfection, did not reduce the incidence of new IMI for any pathogens and did not reduce SCC (p> 0.05). Post-milking teat disinfection applied as a spray is a key component in mastitis control in New Zealand. There was no benefit from the addition of pre-milking disinfection. This study confirms previous findings of the effectiveness of post-milking teat disinfection in reducing the incidence of IMI caused by the common mastitis-causing pathogens in New

Disinfection and regrowth potential of bacillus subtilis spores by ozone, ultraviolet rays and gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Kim, Hae Yeon; Lee, O Mi; Kim, Tae Hun; Lee, Myun Joo; Yu, Seung Ho [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

2009-06-15

Chlorination has been the most commonly adopted disinfection process for the treatment of drinking water. However, Cryptosporidium parvum oocysts and Giardia lamblia cysts were not treated effectively by the common chlorine-based disinfectants. Additionally the regrowth of pathogenic microorganisms is associated with hygienic and aesthetic problems for the consumers of drinking water. Study on alternative disinfection processes such as ozone, UV-C, VUV and gamma irradiation were conducted. Bacillus subtilis spores have been used as a surrogate microorganism for Cryptosporidium parvum oocysts and Giardia lamblia cyst. Inactivation efficiency by ozone was from 30% to 96% within the range of 5 min to 120 min exposures. Inactivation efficiencies by UV-C and VUV were 95.18%, 95.07% at 30 sec, respectively. Inactivation efficiency at gamma irradiation dose of 2 kGy was 99.4%. Microbial regrowths after ozone, UV-C, VUV and gamma irradiation disinfections were also evaluated for 4 days. Bacillus subtilis spores after ozone treatment for 120 min exposure at the rate of 1.68 mg {center_dot} min{sup -1} showed 96.02% disinfection efficiency and significant microbial regrowth. Bacillus subtilis spores after UV-C (99.25% disinfection efficiency) and VUV (99.67% disinfection efficiency) treatments for 5 min showed gradual regrowth. However, inactivation efficiency of gamma irradiation at dose of 1 kGy was 98.8% and the disinfected sample showed no microbial regrowth for 4 days. Therefore, gamma irradiation is the most effective process for the disinfection of pathogenic microorganisms such as oocysts of protozoan parasites among four disinfection process.

Disinfection and regrowth potential of bacillus subtilis spores by ozone, ultraviolet rays and gamma irradiation

International Nuclear Information System (INIS)

Kim, Hae Yeon; Lee, O Mi; Kim, Tae Hun; Lee, Myun Joo; Yu, Seung Ho

2009-01-01

Chlorination has been the most commonly adopted disinfection process for the treatment of drinking water. However, Cryptosporidium parvum oocysts and Giardia lamblia cysts were not treated effectively by the common chlorine-based disinfectants. Additionally the regrowth of pathogenic microorganisms is associated with hygienic and aesthetic problems for the consumers of drinking water. Study on alternative disinfection processes such as ozone, UV-C, VUV and gamma irradiation were conducted. Bacillus subtilis spores have been used as a surrogate microorganism for Cryptosporidium parvum oocysts and Giardia lamblia cyst. Inactivation efficiency by ozone was from 30% to 96% within the range of 5 min to 120 min exposures. Inactivation efficiencies by UV-C and VUV were 95.18%, 95.07% at 30 sec, respectively. Inactivation efficiency at gamma irradiation dose of 2 kGy was 99.4%. Microbial regrowths after ozone, UV-C, VUV and gamma irradiation disinfections were also evaluated for 4 days. Bacillus subtilis spores after ozone treatment for 120 min exposure at the rate of 1.68 mg · min -1 showed 96.02% disinfection efficiency and significant microbial regrowth. Bacillus subtilis spores after UV-C (99.25% disinfection efficiency) and VUV (99.67% disinfection efficiency) treatments for 5 min showed gradual regrowth. However, inactivation efficiency of gamma irradiation at dose of 1 kGy was 98.8% and the disinfected sample showed no microbial regrowth for 4 days. Therefore, gamma irradiation is the most effective process for the disinfection of pathogenic microorganisms such as oocysts of protozoan parasites among four disinfection process

Evaluation of 5 Cleaning and Disinfection Methods for Nets Used to Collect Zebrafish (Danio rerio)

OpenAIRE

Collymore, Chereen; Porelli, Gina; Lieggi, Christine; Lipman, Neil S

2014-01-01

Few standardized methods of cleaning and disinfecting equipment in zebrafish facilities have been published, even though the effectiveness of these procedures is vital to preventing the transmission of pathogenic organisms. Four chemical disinfectants and rinsing with municipal tap water were evaluated for their ability to disinfect nets used to capture zebrafish. The disinfectants included benzalkonium chloride+methylene blue, sodium hypochlorite, chlorine dioxide, and potassium peroxymonosu...

[Surveillance cultures after high-level disinfection of flexible endoscopes in a general hospital].

Science.gov (United States)

Robles, Christian; Turín, Christie; Villar, Alicia; Huerta-Mercado, Jorge; Samalvides, Frine

2014-04-01

Flexible endoscopes are instruments with a complex structure which are used in invasive gastroenterological procedures, therefore high-level disinfection (HLD) is recommended as an appropriate reprocessing method. However, most hospitals do not perform a quality control to assess the compliance and results of the disinfection process. To evaluate the effectiveness of the flexible endoscopes’ decontamination after high-level disinfection by surveillance cultures and to assess the compliance with the reprocessing guidelines. Descriptive study conducted in January 2013 in the Gastroenterological Unit of a tertiary hospital. 30 endoscopic procedures were randomly selected. Compliance with guidelines was evaluated and surveillance cultures for common bacteria were performed after the disinfection process. On the observational assessment, compliance with the guidelines was as follows: pre-cleaning 9 (30%), cleaning 5 (16.7%), rinse 3 (10%), first drying 30 (100%), disinfection 30 (100%), final rinse 0 (0%) and final drying 30 (100%), demonstrating that only 3 of 7 stages of the disinfection process were optimally performed. In the microbiological evaluation, 2 (6.7%) of the 30 procedures had a positive culture obtained from the surface of the endoscope. Furthermore, 1 (4.2%) of the 24 biopsy forcepsgave a positive culture. The organisms isolated were different Pseudomonas species. High-level disinfection procedures were not optimally performed, finding in 6.7% positive cultures of Pseudomonas species.

Cross-Resistance of UV- or Chlorine Dioxide-Resistant Echovirus 11 to Other Disinfectants

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Qingxia Zhong

2017-10-01

Full Text Available The emergence of waterborne viruses with resistance to disinfection has been demonstrated in the laboratory and in the environment. Yet, the implications of such resistance for virus control remain obscure. In this study we investigate if viruses with resistance to a given disinfection method exhibit cross-resistance to other disinfectants. Chlorine dioxide (ClO2- or UV-resistant populations of echovirus 11 were exposed to five inactivating treatments (free chlorine, ClO2, UV radiation, sunlight, and heat, and the extent of cross-resistance was determined. The ClO2-resistant population exhibited cross-resistance to free chlorine, but to none of the other inactivating treatments tested. We furthermore demonstrated that ClO2 and free chlorine act by a similar mechanism, in that they mainly inhibit the binding of echovirus 11 to its host cell. As such, viruses with host binding mechanisms that can withstand ClO2 treatment were also better able to withstand oxidation by free chlorine. Conversely, the UV-resistant population was not significantly cross-resistant to any other disinfection treatment. Overall, our results indicate that viruses with resistance to multiple disinfectants exist, but that they can be controlled by inactivating methods that operate by a distinctly different mechanism. We therefore suggest to utilize two disinfection barriers that act by different mechanisms in order to control disinfection-resistant viruses.

Identification of barriers and research opportunities to improve the effective and efficient application of adjunct UVC surface disinfection in healthcare

Science.gov (United States)

Martinello, Richard A.; Miller, Shelly L.; Fabian, M. Patricia; Peccia, Jordan

2018-02-01

Healthcare associated infections (HAI) affect approximately 1 of every 25 hospitalized patients, lead to substantial morbidity and mortality, degrade patient experience and are costly. Risks for HAI are multifactorial and it is known that microbial contamination of the healthcare environment increases risk for HAI. Portable ultraviolet-C (UVC) surface disinfection as an adjunct to standard hospital disinfection has been shown to decrease both surface microbial contamination and HAI. However, there remain significant gaps in the understanding of the efficient and effective application of UVC in healthcare. Specific barriers identified are: 1) the variability in size, shape, and surface materials of hospital rooms as well as the presence of medical devices and furniture, which impacts the amount of UVC energy delivered to surfaces and its disinfection efficiency; 2) the significant resources needed to acquire and efficiently use UVC equipment and achieve the desired patient benefits- a particular challenge for complex healthcare facilities with limited operating margins; and 3) the lack of implementation guidance and industry standard methods for measuring the UVC output and antimicrobial effects from the multiple commercial UVC options available. An improved understanding of the efficient and effective use of UVC surface disinfection in healthcare and the implementation of standard device industry metrics may lead to increased use and decrease the burden of HAI.

Effect oof some antibiotics, disinfectants, and UV light on vability of vegetative cells and spores of C1. perfringend type A

International Nuclear Information System (INIS)

Rymkiewicz, D.

1977-01-01

Cells and spores of 40 strains of C1. perfringens type A, pathogenic for guinea pigs, were tested for resistance to antibiotics, drugs, disinfectants used in surgery and in bacteriological laboratories, and UV light. No correlation was found between thermoresistance of spores and their resistance to other bactericidal agents. Among the common disinfectants, iodine solution showed strong bactericidal and sporostatic activity. Good bactericidal effect was also obtained by combined action of Vescodin and UV light. Drug resistance of C1. perfringens type A strains changed clearly in the past 10 years. Strains inducing gangrene became resistant to penicillin and tetracyclines, which hitherto were commonly applied. Ampicilin can now be recommended, as the antibiotic with strong bactericidal and sporostatic action. (author)

Laboratory and field investigation of chemical disinfection of combined sewer overflow in Copenhagen area

DEFF Research Database (Denmark)

Chhetri, Ravi Kumar; Thornberg, Dines; Berner, Jesper

We investigated the possibility to apply performic acid (PFA) and peracetic acid (PAA) for disinfection of combined sewer overflow (CSO) in existing CSO management infrastructures. The disinfection power of PFA and PAA to Escherichia coli (E. coli) and enterococcus were studied in batch scale...... and pre-field experiment. In batch scale experiment 2.5 mg·L -1 PAA removed around 4 log unit of E. coli and enterococcus from CSO with long contact time. Removal of E. coli and enterococcus from CSO were always around or above 3 log unit using 2-4 mg·L -1 PFA with short contact time in batch scale...... and pre-field experiment. There were no toxicological effect measured by Vibrio fischeri when CSO was disinfected with PFA, slight toxicological effect was observed on CSO disinfected with PAA. When the design for PFA based disinfection was applied to CSO collected from an authentic event. Disinfection...

Disinfection procedures for in vitro propagation of Anthurium

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Silva Jaime A. Teixeira da

2015-06-01

Full Text Available Disinfection of plant material is the most important step of the tissue culture protocol. In this process, an attempt is made to eliminate microbial contaminants from the surface and interior of plant material, thus giving the explant a fighting chance at survival in vitro. Initial cultures of Anthurium species and cultivars, which are usually established from ex vitro material grown in a greenhouse, pots or in the field, easily contaminate the in vitro milieu. This review highlights the differences in disinfection protocols that exist for different species or cultivars of Anthurium. The protocol needs to be adjusted based on the material used: spadices, spathes, seeds, leaves, or roots. Regrettably, most of the currently published protocols, derived from a literature that spans over 100 published papers, have numerous weaknesses and flaws in the information provided pertaining to disinfection and infection levels. Advice for future Anthurium researchers should thus be followed cautiously.

Immunomagnetic separation combined with RT-qPCR for determining the efficacy of disinfectants against human noroviruses

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Pengbo Liu

2015-03-01

Full Text Available Summary: Little is known about the effectiveness of disinfectants against human noroviruses (NoV partially because human NoV cannot be routinely cultured in laboratory. The objective of this study was to develop a NoV monoclonal antibody-conjugated immunomagnetic separation (IMS procedure combined with real-time reverse transcription polymerase chain reaction (RT-qPCR assays to study the in vitro efficacy of disinfectants against human NoV. Monoclonal antibodies against Norwalk virus (NV, GI.1 and NoV GII.4 were produced using unique NoV capsid proteins, and the antibodies were conjugated to magnetic Dynalbeads. The immunomagnetic beads were used to simultaneously capture intact NoV in samples and effectively remove PCR inhibitors. We examined the efficacy of ethanol, sodium hypochlorite, nine commercially available disinfectants, and one prototype disinfectant using the IMS/RT-qPCR. The sensitivity of this procedure was approximately 100 virus particles for both the NV and GII.4 viruses. The average log reductions in in vitro activities varied between disinfectants. The prototype disinfectant produced an average 3.19-log reduction in NV and a 1.38-log reduction in GII.4. The prototype disinfectant is promising of inactivating NoV. This method can be used to evaluate in vitro activity of disinfectants against human NoV. The IMS/RT-qPCR method is promising as an effective method to remove PCR inhibitors in disinfectants and enable the evaluation of the efficacy of disinfectants. Keywords: Disinfectant, Norovirus, Immunomagnetic separation, Real-time RT-PCR, PCR inhibition

Virucidal efficacy of peracetic acid for instrument disinfection

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Britta Becker

2017-11-01

Full Text Available Abstract Background Various peracetic-acid (PAA-based products for processing flexible endoscopes on the market are often based on a two-component system including a cleaning step before the addition of PAA as disinfectant. The peracetic acid concentrations in these formulations from different manufacturers are ranging from 400 to 1500 ppm (part per million. These products are used at temperatures between 20 °C and 37 °C. Since information on the virus-inactivating properties of peracetic acid at different concentrations and temperature is missing, it was the aim of the study to evaluate peracetic acid solutions against test viruses using the quantitative suspension test, EN 14476. In addition, further studies were performed with the recently established European pre norm (prEN 17111:2017 describing a carrier assay for simulating practical conditions using frosted glass. Methods In the first step of examination, different PAA solutions between 400 and 1500 ppm were tested at 20 °C, 25 °C, and 35 °C with three test viruses (adenovirus, murine norovirus and poliovirus necessary for creating a virucidal action according to the European Norm, EN 14476. A second step for simulating practical conditions based on prEN 17111:2017 followed by spreading a test virus together with soil load onto a glass carrier which was immerged into a peracetic acid solution. A fixed exposure time of five minutes was used in all experiments. Results In the quantitative suspension test 1500 ppm PAA solution was needed at 35 °C for five minutes for the inactivation of poliovirus, whereas only 400 ppm at 20 °C for adeno- and murine norovirus were necessary. In the carrier assay 400 ppm peracetic acid at 20 °C were sufficient for adenovirus inactivation, whereas 600 ppm PAA were needed at 25 °C and 35 °C and 1000 ppm at 20 °C for murine norovirus. A PAA solution with 1000 ppm at 35 °C was required for complete inactivation of poliovirus

Evaluating the Sporicidal Activity of Disinfectants against Clostridium difficile and Bacillus amyloliquefaciens Spores by Using the Improved Methods Based on ASTM E2197-11.

Science.gov (United States)

Uwamahoro, Marie Christine; Massicotte, Richard; Hurtubise, Yves; Gagné-Bourque, François; Mafu, Akier Assanta; Yahia, L'Hocine

2018-01-01

Spore-forming pathogenic bacteria, such as Clostridium difficile , are associated with nosocomial infection, leading to the increased use of sporicidal disinfectants, which impacts socioeconomic costs. However, C. difficile can be prevented using microorganisms such as Bacillus amyloliquefaciens , a prophylactic agent that has been proven to be effective against it in recent tests or it can be controlled by sporicidal disinfectants. These disinfectants against spores should be evaluated according to a known and recommended standard. Unfortunately, some newly manufactured disinfectants like Bioxy products have not yet been tested. ASTM E2197-11 is a standard test that uses stainless steel disks (1 cm in diameter) as carriers, and the performance of the test formulation is calculated by comparing the number of viable test organisms to that on the control carriers. Surface tests are preferable for evaluating disinfectants with sporicidal effects on hard surfaces. This study applies improved methods, based on the ASTM E2197-11 standard, for evaluating and comparing the sporicidal efficacies of several disinfectants against spores of C. difficile and B. amyloliquefaciens , which are used as the test organisms. With the improved method, all spores were recovered through vortexing and membrane filtration. The results show that chlorine-based products are effective in 5 min and Bioxy products at 5% w/v are effective in 10 min. Although Bioxy products may take longer to prove their effectiveness, their non-harmful effects to hospital surfaces and people have been well established in the literature.

Chloramination of Concentrated Drinking Water for Disinfection Byproduct Mixtures Creation- Indianapolis

Science.gov (United States)

Complex mixtures of disinfection by-products (DBPs) are formed when the disinfectant oxidizes constituents (e.g., natural organic matter (NOM) and organic pollutants) found in the source water. Since 1974, over 600 DBPs have been identified in drinking water. Despite intense iden...

Efficacy of detergent and water versus bleach for disinfection of direct contact ophthalmic lenses.

Science.gov (United States)

Abbey, Ashkan M; Gregori, Ninel Z; Surapaneni, Krishna; Miller, Darlene

2014-06-01

Although manufacturers recommend cleaning ophthalmic lenses with detergent and water and then with a specific disinfectant, disinfectants are rarely used in ophthalmic practices. The aim of this pilot study was to evaluate the efficacy of detergent and water versus that of bleach, a recommended disinfectant, to eliminate common ocular bacteria and viruses from ophthalmic lenses. Three bacterial strains (Staphylococcus epidermidis, Corynebacterium straitum, and methicillin-resistant Staphylococcus aureus and 2 viral strains (adenovirus and herpes simplex virus [HSV] type-1) were individually inoculated onto 20 gonioscopy and laser lenses. The lenses were washed with detergent and water and then disinfected with 10% bleach. All the lenses were cultured after inoculation, after washing with detergent and water, and after disinfecting with the bleach. Bacterial cultures in thioglycollate broth were observed for 3 weeks, and viral cultures were observed for 2 weeks. The presence of viruses was also detected by multiplex polymerase chain reaction (PCR). All 20 lenses inoculated with S. epidermidis, C. straitum, adenovirus, and HSV-1 showed growth after inoculation but no growth after washing with detergent/water and after disinfecting with the bleach. All lenses showed positive HSV and adenovirus PCR results after inoculation and negative PCR results after washing with detergent/water and after disinfecting with bleach. All methicillin-resistant S. aureus-contaminated lenses showed growth after inoculation and no growth after washing with detergent and water. However, 1 lens showed positive growth after disinfecting with bleach. Cleaning with detergent and water seemed to effectively eliminate bacteria and viruses from the surface of contaminated ophthalmic lenses. Further studies are warranted to design practical disinfection protocols that minimize lens damage.

A practical demonstration of water disinfection using TiO2 films and sunlight.

Science.gov (United States)

Gelover, Silvia; Gómez, Luis A; Reyes, Karina; Teresa Leal, Ma

2006-10-01

The scope of this study is the assessment of the efficiency of solar disinfection by heterogeneous photocatalysis with sol-gel immobilized (titanium dioxide) TiO2 films over glass cylinders. The solar disinfection process known as SODIS was considered as a reference. Spring water naturally polluted with coliform bacteria was exposed to sunlight in plastic bottles with and without TiO2 over simple solar collectors and the disinfection effectiveness was measured. Total and fecal coliforms quantification was performed by means of the chromogenic substrate method in order to obtain the efficiency of each disinfection treatment. The disinfection with TiO2 was more efficient than the SODIS process, inactivating total coliforms as well as fecal coliforms. On a sunny day (more than 1000 W m(-2) irradiance), it took the disinfection with immobilized TiO2 15 min of irradiation to inactivate the fecal coliforms to make them undetectable. For inactivation of total coliforms, 30 min was required, so that in less than half the time it takes SODIS, the treated water complies with the microbial standards for drinking water in Mexico. Another important part of this study has been to determine the bacterial regrowth in water after the disinfection processes were tested. After SODIS, bacterial regrowth of coliforms was observed. In contrast, when using the TiO2 catalyst, coliforms regrowth was not detected, neither for total nor for fecal coliforms. The disinfection process using TiO2 kept treated water free of coliforms at least for seven days after sun irradiation. This demonstration opens the possibility of application of this simple method in rural areas of developing countries.

The tail of two models: Impact of circularity and biomass non-homogeneity on UV disinfection of wastewater flocs.

Science.gov (United States)

Azimi, Y; Liu, Y; Tan, T C; Allen, D G; Farnood, R R

2017-12-01

The effects of floc structural characteristics, i.e. shape and dense biomass distribution, were evaluated on ultraviolet (UV) disinfection resistance, represented by the tailing level of the UV dose response curve (DRC). Ellipsoid-shaped flocs of similar volume and different projected circularities were constructed in-silico and a mathematical model was developed to compare their UV DRC tailing levels (indicative of UV-resistance). It was found that floc shape can significantly influence tailing level, and rounder flocs (i.e. flocs with higher circularity) were more UV-resistant. This result was confirmed experimentally by obtaining UV DRCs of two 75-90 μm floc populations with different percentages (20% vs. 30%) of flocs with circularities higher than 0.5. The population enriched in less circular flocs (i.e. 20% flocs with circularities >0.5) had a lower tailing level (at least by 1-log) compared to the other population. The second model was developed to describe variations in UV disinfection kinetics observed in flocs with transverse vs. radial biomass non-homogeneity, indicative of biofilm-originated vs. suspended flocs. The varied-density hemispheres model and shell-core model were developed to simulate transverse and radial non-homogeneity, respectively. The UV DRCs were mathematically constructed and biofilm-originated flocs showed higher UV resistance compared to suspended flocs. The calculated UV DRCs agreed well with the experimental data collected from activated sludge and trickling filter flocs (no fitting parameters were used). These findings provide useful information in terms of designing/modifying upstream processes for reducing UV disinfection energy demand. Copyright © 2017 Elsevier Ltd. All rights reserved.

Wastewater disinfection alternatives: chlorine, ozone, peracetic acid, and UV light.

Science.gov (United States)

Mezzanotte, V; Antonelli, M; Citterio, S; Nurizzo, C

2007-11-01

Disinfection tests were carried out at pilot scale to compare the disinfection efficiency of ozone, sodium hypochlorite (NaOCl), peracetic acid (PAA), and UV irradiation. Total coliforms, fecal coliforms, and Escherichia coli were monitored as reference microorganisms. Total heterotrophic bacteria (THB) were also enumerated by cytometry. At similar doses, NaOCl was more effective than PAA, and its action was less affected by contact time. The results obtained by ozonation were comparable for total coliforms, fecal coliforms, and E. coli. On the contrary, some differences among the three indicators were observed for NaOCl, PAA, and UV. Differences increased with increasing values of the disinfectant concentration times contact time (C x t) and were probably the result of different initial counts, as total coliforms include fecal coliforms, which include E. coli. The UV irradiation lead to complete E. coli removals, even at low doses (10 to 20 mJ/cm2). Total heterotrophic bacteria appeared to be too wide a group to be a good disinfection indicator; no correlation was found among THB inactivation, dose, and contact time.

Methodological approaches to disinfection of human hepatitis B virus.

OpenAIRE

Prince, D L; Prince, H N; Thraenhart, O; Muchmore, E; Bonder, E; Pugh, J

1993-01-01

Three commercial disinfectants (two quaternary formulations and one phenolic) were tested against human hepatitis B virus (HHBV). The treated virus was assayed for infectivity by the chimpanzee assay and for morphological alteration by the Morphological Alteration and Disintegration Test. The same agents were tested against duck hepatitis B virus in a duck hepatocyte infectivity assay. It is apparent that human and duck hepatitis viruses were relatively susceptible to disinfection, becoming n...

Peracetic acid as an alternative disinfection technology for wet weather flows.

Science.gov (United States)

Coyle, Elizabeth E; Ormsbee, Lindell E; Brion, Gail M

2014-08-01

Rain-induced wet weather flows (WWFs) consist of combined sewer overflows, sanitary sewer overflows, and stormwater, all of which introduce pathogens to surface waters when discharged. When people come into contact with the contaminated surface water, these pathogens can be transmitted resulting in severe health problems. As such, WWFs should be disinfected. Traditional disinfection technologies are typically cost-prohibitive, can yield toxic byproducts, and space for facilities is often limited, if available. More cost-effective alternative technologies, requiring less space and producing less harmful byproducts are currently being explored. Peracetic acid (PAA) was investigated as one such alternative and this research has confirmed the feasibility and applicability of using PAA as a disinfectant for WWFs. Peracetic acid doses ranging from 5 mg/L to 15 mg/L over contact times of 2 to 10 minutes were shown to be effective and directly applicable to WWF disinfection.

Application of Highly Purified Electrolyzed Chlorine Dioxide for Tilapia Fillet Disinfection

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Chen-Hsing Yu

2014-01-01

Full Text Available This research aimed to develop an electrolysis method to generate high-concentration chlorine dioxide (ClO2 for tilapia fillet disinfection. The designed generator produced up to 3500 ppm of ClO2 at up to 99% purity. Tilapia fillets were soaked in a 400 ppm ClO2 solution for 5, 10, and 25 min. Results show that total plate counts of tilapia, respectively, decreased by 5.72 to 3.23, 2.10, and 1.09 log CFU/g. In addition, a 200 ppm ClO2 solution eliminated coliform bacteria and Escherichia coli in 5 min with shaking treatment. Furthermore, ClO2 and trihalomethanes (THMs residuals on tilapia fillets were analyzed by GC/MS and were nondetectable (GC-MS detection limit was 0.12 ppb. The results conform to Taiwan’s environmental protection regulations and act governing food sanitation.

Impact of terminal cleaning and disinfection on isolation of Acinetobacter baumannii complex from inanimate surfaces of hospital rooms by quantitative and qualitative methods.

Science.gov (United States)

Manian, Farrin A; Griesnauer, Sandra; Senkel, Diane

2013-04-01

Quantitative broth cultures were obtained from hospital rooms newly vacated by patients positive for multidrug-resistant Acinetobacter baumannii complex (ABC) before and after terminal cleaning and disinfection. Of 10 ABC-positive precleaned room surfaces, 6 (60%) remained culture-positive after terminal cleaning and disinfection. Of a total of 16 room surfaces with detectable ABC by the quantitative method, 5 (31.2%; 95% confidence interval, 13.9%-55.8%) were also culture-positive by the qualitative technique. Copyright © 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Frequency of use controls chemical leaching from drinking-water containers subject to disinfection.

Science.gov (United States)

Andra, Syam S; Makris, Konstantinos C; Shine, James P

2011-12-15

Microbial-, and chemical-based burden of disease associated with lack of access to safe water continues to primarily impact developing countries. Cost-effective health risk-mitigating measures, such as of solar disinfection applied to microbial-contaminated water stored in plastic bottles have been increasingly tested in developing countries adversely impacted by epidemic water-borne diseases. Public health concerns associated with chemical leaching from water packaging materials led us to investigate the magnitude and variability of antimony (Sb) and bromine (Br) leaching from reused plastic containers (polyethylene terephthalate, PET; and polycarbonate, PC) subject to UV and/or temperature-driven disinfection. The overall objective of this study was to determine the main and interactive effects of temperature, UV exposure duration, and frequency of bottle reuse on the extent of leaching of Sb and Br from plastic bottles into water. Regardless of UV exposure duration, frequency of reuse (up to 27 times) was the major factor that linearly increased Sb leaching from PET bottles at all temperatures tested (13-47 °C). Leached Sb concentrations (∼360 ng L(-1)) from the highly reused (27 times) PET bottles (minimal Sb leaching from PC bottles, water at much lower concentrations. Additional research on potential leaching of organic chemicals from water packaging materials is deemed necessary under relevant environmental conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

CHO cell cytotoxicity and genotoxicity analyses of disinfection by-products: An updated review

Institute of Scientific and Technical Information of China (English)

Elizabeth D.Wagner; Michael J.Plewa

2017-01-01

The disinfection of drinking water is an important public health service that generates high quality,safe and palatable tap water.The disinfection of drinking water to reduce waterborne disease was an outstanding public health achievement of the 20th century.An unintended consequence is the reaction of disinfectants with natural organic matter,anthropogenic contaminants and bromide/iodide to form disinfection by-products (DBPs).A large number of DBPs are cytotoxic,neurotoxic,mutagenic,genotoxic,carcinogenic and teratogenic.Epidemiological studies demonstrated low but significant associations between disinfected drinking water and adverse health effects.The distribution of DBPs in disinfected waters has been well defined by advances in high precision analytical chemistry.Progress in the analytical biology and toxicology of DBPs has been forthcoming.The objective of this review was to provide a detailed presentation of the methodology for the quantitative,comparative analyses on the induction of cytotoxicity and genotoxicity of 103 DBPs using an identical analytical biological platform and endpoints.A single Chinese hamster ovary cell line was employed in the assays.The data presented are derived from papers published in the literature as well as additional new data and represent the largest direct quantitative comparison on the toxic potency of both regulated and emerging DBPs.These data may form the foundation of novel research to define the major forcing agents of DBP-mediated toxicity in disinfected water and may play an important role in achieving the goal of making safe drinking water better.

Evaluation of AISI Type 304 stainless steel as a suitable surface material for evaluating the efficacy of peracetic acid-based disinfectants against Clostridium difficile spores.

Directory of Open Access Journals (Sweden)

Elaine Black

Full Text Available Disinfectants play an important role in controlling microbial contamination on hard surfaces in hospitals. The effectiveness of disinfectants in real life can be predicted by laboratory tests that measure killing of microbes on carriers. The modified Quantitative Disk Carrier Test (QCT-2 is a standard laboratory method that employs American Iron and Steel Institute (AISI Type 430 stainless steel carriers to measure hospital disinfectant efficacy against Clostridium difficile spores. The formation of a rust-colored precipitate was observed on Type 430 carriers when testing a peracetic acid (PAA-based disinfectant with the QCT-2 method. It was hypothesized that the precipitate was indicative of corrosion of the Type 430 carrier, and that corrosion could impact efficacy results. The objective of this study was to compare the suitability of AISI Type 430 to Type 304 stainless steel carriers for evaluating PAA-based disinfectants using the QCT-2 method. Type 304 is more corrosion-resistant than Type 430, is ubiquitous in healthcare environments, and is used in other standard methods. Suitability of the carriers was evaluated by comparing their impacts on efficacy results and PAA degradation rates. In efficacy tests with 1376 ppm PAA, reductions of C. difficile spores after 5, 7 and 10 minutes on Type 430 carriers were at least about 1.5 log10 lower than reductions on Type 304 carriers. In conditions simulating a QCT-2 test, PAA concentration with Type 430 carriers was reduced by approximately 80% in 10 minutes, whereas PAA concentration in the presence of Type 304 carriers remained stable. Elemental analyses of residues on each carrier type after efficacy testing were indicative of corrosion on the Type 430 carrier. Use of Type 430 stainless steel carriers for measuring the efficacy of PAA-based disinfectants should be avoided as it can lead to an underestimation of real life sporicidal efficacy. Type 304 stainless steel carriers are recommended as a

Evaluation of AISI Type 304 stainless steel as a suitable surface material for evaluating the efficacy of peracetic acid-based disinfectants against Clostridium difficile spores.

Science.gov (United States)

Black, Elaine; Owens, Krista; Staub, Richard; Li, Junzhong; Mills, Kristen; Valenstein, Justin; Hilgren, John

2017-01-01

Disinfectants play an important role in controlling microbial contamination on hard surfaces in hospitals. The effectiveness of disinfectants in real life can be predicted by laboratory tests that measure killing of microbes on carriers. The modified Quantitative Disk Carrier Test (QCT-2) is a standard laboratory method that employs American Iron and Steel Institute (AISI) Type 430 stainless steel carriers to measure hospital disinfectant efficacy against Clostridium difficile spores. The formation of a rust-colored precipitate was observed on Type 430 carriers when testing a peracetic acid (PAA)-based disinfectant with the QCT-2 method. It was hypothesized that the precipitate was indicative of corrosion of the Type 430 carrier, and that corrosion could impact efficacy results. The objective of this study was to compare the suitability of AISI Type 430 to Type 304 stainless steel carriers for evaluating PAA-based disinfectants using the QCT-2 method. Type 304 is more corrosion-resistant than Type 430, is ubiquitous in healthcare environments, and is used in other standard methods. Suitability of the carriers was evaluated by comparing their impacts on efficacy results and PAA degradation rates. In efficacy tests with 1376 ppm PAA, reductions of C. difficile spores after 5, 7 and 10 minutes on Type 430 carriers were at least about 1.5 log10 lower than reductions on Type 304 carriers. In conditions simulating a QCT-2 test, PAA concentration with Type 430 carriers was reduced by approximately 80% in 10 minutes, whereas PAA concentration in the presence of Type 304 carriers remained stable. Elemental analyses of residues on each carrier type after efficacy testing were indicative of corrosion on the Type 430 carrier. Use of Type 430 stainless steel carriers for measuring the efficacy of PAA-based disinfectants should be avoided as it can lead to an underestimation of real life sporicidal efficacy. Type 304 stainless steel carriers are recommended as a suitable

Evaluation of AISI Type 304 stainless steel as a suitable surface material for evaluating the efficacy of peracetic acid-based disinfectants against Clostridium difficile spores

Science.gov (United States)

Owens, Krista; Staub, Richard; Li, Junzhong; Mills, Kristen; Valenstein, Justin; Hilgren, John

2017-01-01

Disinfectants play an important role in controlling microbial contamination on hard surfaces in hospitals. The effectiveness of disinfectants in real life can be predicted by laboratory tests that measure killing of microbes on carriers. The modified Quantitative Disk Carrier Test (QCT-2) is a standard laboratory method that employs American Iron and Steel Institute (AISI) Type 430 stainless steel carriers to measure hospital disinfectant efficacy against Clostridium difficile spores. The formation of a rust-colored precipitate was observed on Type 430 carriers when testing a peracetic acid (PAA)-based disinfectant with the QCT-2 method. It was hypothesized that the precipitate was indicative of corrosion of the Type 430 carrier, and that corrosion could impact efficacy results. The objective of this study was to compare the suitability of AISI Type 430 to Type 304 stainless steel carriers for evaluating PAA-based disinfectants using the QCT-2 method. Type 304 is more corrosion-resistant than Type 430, is ubiquitous in healthcare environments, and is used in other standard methods. Suitability of the carriers was evaluated by comparing their impacts on efficacy results and PAA degradation rates. In efficacy tests with 1376 ppm PAA, reductions of C. difficile spores after 5, 7 and 10 minutes on Type 430 carriers were at least about 1.5 log10 lower than reductions on Type 304 carriers. In conditions simulating a QCT-2 test, PAA concentration with Type 430 carriers was reduced by approximately 80% in 10 minutes, whereas PAA concentration in the presence of Type 304 carriers remained stable. Elemental analyses of residues on each carrier type after efficacy testing were indicative of corrosion on the Type 430 carrier. Use of Type 430 stainless steel carriers for measuring the efficacy of PAA-based disinfectants should be avoided as it can lead to an underestimation of real life sporicidal efficacy. Type 304 stainless steel carriers are recommended as a suitable

Drinking water and biofilm disinfection by Fenton-like reaction.

Science.gov (United States)

Gosselin, F; Madeira, L M; Juhna, T; Block, J C

2013-10-01

A Fenton-like disinfection process was conducted with Fenton's reagent (H2O2) at pH 3 or 5 on autochthonous drinking water biofilms grown on corroded or non-corroded pipe material. The biofilm disinfection by Fenton-like oxidation was limited by the low content of iron and copper in the biomass grown on non-corroded plumbing. It was slightly improved by spiking the distribution system with some additional iron source (soluble iron II or ferrihydrite particles appeared as interesting candidates). However successful in situ disinfection of biofilms was only achieved in fully corroded cast iron pipes using H2O2 and adjusting the pH to 5. These new results provide additional support for the use of Fenton's processes for cleaning drinking water distribution systems contaminated with biological agents or organics. Copyright © 2013 Elsevier Ltd. All rights reserved.

Environmental impact of solution mining for uranium

International Nuclear Information System (INIS)

Hunkin, G.G.

1975-01-01

Compared with most other mining systems, uranium solution mining has a negligible effect on such environmental factors as surface disturbance, interference with natural groundwater quality and distribution, and aerial discharge of radionuclides. The following topics are discussed: the process, personnel safety and health, tailings disposal, impact on groundwater, operating licenses and controls, legislation, and economics. It is concluded that engineered well systems and controlled input/production flow rates, combined with full recirculation systems that maintain constant fluid volumes in the mineralized formations, result in containment of leach solutions within the operating area. The very dilute leach solutions, compatible with natural groundwaters, ensure that no environmental damage results, even if a loss of control occurred. Reduction in the number of processing steps and virtual elimination of operator hazards, waste disposal and land rehabilitation costs help in reducing overall costs

Thermal disinfection of hotels, hospitals, and athletic venues hot water distribution systems contaminated by Legionella species.

Science.gov (United States)

Mouchtouri, Varvara; Velonakis, Emmanuel; Hadjichristodoulou, Christos

2007-11-01

Legionella spp. (> or = 500 cfu liter(-1)) were detected in 92 of 497 water distribution systems (WDS) examined. Thermal disinfection was applied at 33 WDS. After the first and second application of the disinfection procedure, 15 (45.4%) and 3 (9%) positive for remedial actions WDS were found, respectively. Legionella pneumophila was more resistant to thermal disinfection than Legionella non-pneumophila spp. (relative risk [RR]=5.4, 95% confidence intervals [CI]=1-35). WDS of hotels with oil heater were more easily disinfected than those with electrical or solar heater (RR=0.4 95% CI=0.2-0.8). Thermal disinfection seems not to be efficient enough to eliminate legionellae, unless repeatedly applied and in combination with extended heat flushing, and faucets chlorine disinfection.

Chemical disinfection of combined sewer overflow waters using performic acid or peracetic acids

DEFF Research Database (Denmark)

Chhetri, Ravi Kumar; Thornberg, Dines; Berner, Jesper

2014-01-01

We investigated the possibility of applying performic acid (PFA) and peracetic acid (PAA) for disinfection of combined sewer overflow (CSO) in existing CSO management infrastructures. The disinfection power of PFA and PAA towards Escherichia coli (E. coli) and Enterococcus was studied in batch......-scale and pre-field experiments. In the batch-scale experiment, 2.5 mg L− 1 PAA removed approximately 4 log unit of E. coli and Enterococcus from CSO with a 360 min contact time. The removal of E. coli and Enterococcus from CSO was always around or above 3 log units using 2–4 mg L− 1 PFA; with a 20 min contact...... time in both batch-scale and pre-field experiments. There was no toxicological effect measured by Vibrio fischeri when CSO was disinfected with PFA; a slight toxic effect was observed on CSO disinfected with PAA. When the design for PFA based disinfection was applied to CSO collected from an authentic...

The potential for optical beam shaping of UV laser sources for mass scale quarantine disinfection applications

Science.gov (United States)

Lizotte, Todd

2010-08-01

Recent events concerning H1N1 "swine flu", have demonstrated to the world the significant potential of rapid increases in death and illness among all age groups and even among the healthy population [1] when a highly infectious influenza virus is introduced. In terms of mass casualties due to a pandemic, preparedness and response planning must be done. One course of action to prevent a pandemic outbreak or reduce the impact of a bioterrorist event is the use of isolation or quarantine facilities. The first level of isolation or quarantine is within the personal residence of the person exposed or infected. In the case where, the specific virus is extremely contagious and its onset of symptoms is rapid and severe, there will be a need for the deployment and setup of larger self contained quarantine facilities. Such facilities are used to house infectious individuals to minimize the exposure of susceptible individuals to contagious individuals, especially when specialized care or treatment is required and during the viral shedding period (5 to 7 days). These types of facilities require non-shared air conditioning, heating and ventilating systems where 100% of air is vented to the outside through a series of disinfection systems and staged filters. Although chemical disinfection is possible, there is a desire to incorporate intense UV radiation as a means to deactivate and disinfect airborne virus within hospital settings and isolated mass scale quarantine facilities. UV radiation is also being considered for disinfection of contaminated surfaces, such as table tops, walls and floors in hospitals and temporary quarantine facilities. In such applications the use of UV bulb technology can create many problems, for instance bulb technology requires numerous bulbs to treat a large volume of air, generates significant heat, uses significant power and does not produce large fluxes of UV light efficiently. This paper provides several methods of creating quarantine level

Baby bottle steam sterilizers for disinfecting home nebulizers inoculated with non-tuberculous mycobacteria.

Science.gov (United States)

Towle, D; Callan, D A; Lamprea, C; Murray, T S

2016-03-01

Non-tuberculous mycobacteria (NTMb), present in environmental water sources, can contribute to respiratory infection in patients with chronic pulmonary disease. Contaminated nebulizers are a potential source of respiratory infection. Treatment with baby bottle steam sterilizers disinfects home nebulizers inoculated with bacterial pathogens but whether this method works for disinfection of NTMb is unclear. Baby bottle steam sterilization was compared with vigorous water washing for disinfecting home nebulizers inoculated with NTMb mixed with cystic fibrosis sputum. No NTMb was recovered from any nebulizers after steam treatment whereas viable NTMb grew after water washing, demonstrating that steam sterilization effectively disinfects NTMb-inoculated nebulizers. Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Demonstration of disinfection procedure for the development of accurate blood glucose meters in accordance with ISO 15197:2013

Science.gov (United States)

Lin, Wen-Ye; Chang, Jung-Tzu; Chu, Chun-Feng

2017-01-01

Despite measures to reduce disease transmission, a risk can occur when blood glucose meters (BGMs) are used on multiple individuals or by caregivers assisting a patient. The laboratory and in-clinic performance of a BGM system before and after disinfection should be demonstrated to guarantee accurate readings and reliable control of blood glucose (BG) for patients. In this study, an effective disinfection procedure, conducting wiping 10 times to assure a one minute contact time of the disinfectant on contaminated surface, was first demonstrated using test samples of the meter housing materials, including acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), and polycarbonate (PC), in accordance with ISO 15197:2013. After bench studies comprising 10,000 disinfection cycles, the elemental compositions of the disinfected ABS, PMMA, and PC samples were almost the same as in the original samples, as indicated by electron spectroscopy for chemical analysis. Subsequently, the validated disinfection procedure was then directly applied to disinfect 5 commercial BGM systems composed of ABS, PMMA, or PC to observe the effect of the validated disinfection procedure on meter accuracy. The results of HBsAg values after treatment with HBV sera and disinfectant wipes for each material were less than the LoD of each material of 0.020 IU/mL. Before and after the multiple disinfection cycles, 900 of 900 samples (100%) were within the system accuracy requirements of ISO 15197:2013. All of the systems showed high performance before and after the series of disinfection cycles and met the ISO 15197:2013 requirements. In addition, our results demonstrated multiple cleaning and disinfection cycles that represented normal use over the lifetime of a meter of 3–5 years. Our validated cleaning and disinfection procedure can be directly applied to other registered disinfectants for cleaning commercial BGM products in the future. PMID:28683148

Impact of pulsed xenon ultraviolet disinfection on surface contamination in a hospital facility's expressed human milk feed preparation area.

Science.gov (United States)

Dippenaar, Ricky; Smith, Johan

2018-02-23

Expressed human milk (EHM) feed preparation areas represent a potential source of unintentional nosocomial infection. Daily disinfection of environmental surfaces remains an essential intervention to mitigate nosocomial infections. The inefficiency of conventional cleaning and disinfection contributes to an increased risk for the acquisition of multi-drug resistant pathogens. "Non touch" technologies such as the pulsed xenon ultraviolet (PX-UVD) light device have documented sustained reduction in surface bacterial colonization and reduced cross contamination. The impact of a PX-UVD on surface colony forming units per square centimeter (cfu/cm 2 ) in feed preparation areas was evaluated following its implementation as standard care. A quasi-experimental study was performed documenting bacterial colonization from 6 high risk feed preparation areas in a community care hospital in South Africa. Pre and post conventional cleaning neutralizing rinse swabs were collected fortnightly over a 16 week control period prior to the introduction of the PX-UVD and compared to a matching set of samples for the PX-UVD period. A 90% reduction in total surface bioburden was noted from the control period (544 cfu/cm 2 ) compared to the corresponding PX-UVD period (50 cfu/cm 2 ). Sub -analysis of both the Pre-clean Control: Pre-clean PX-UVD counts as well as the Post-clean Control: Post-clean PX-UVD counts noted significant improvements (p cleaning total surface bioburden following exposure to the PX-UVD (p = 0.0004). The introduction of the PX-UVD was associated with a sustained reduction in the pre clean bioburden counts with a risk trend (per week) 0.19, (95% CI [0.056, 0.67], p = 0.01). The use of a PX-UVD as adjunct to standard cleaning protocols was associated with a significant decrease in surface bioburden. The study demonstrated the inefficiency of conventional cleaning. Persistence of potentially pathological species in both periods highlights current health

Combined effects of coagulation and adsorption on ultrafiltration membrane fouling control and subsequent disinfection in drinking water treatment.

Science.gov (United States)

Xing, Jiajian; Liang, Heng; Cheng, Xiaoxiang; Yang, Haiyan; Xu, Daliang; Gan, Zhendong; Luo, Xinsheng; Zhu, Xuewu; Li, Guibai

2018-06-02

This study investigated the combined effects of coagulation and powdered activated carbon (PAC) adsorption on ultrafiltration (UF) membrane fouling control and subsequent disinfection efficiency through filtration performance, dissolved organic carbon (DOC) removal, fluorescence excitation-emission matrix (EEM) spectroscopy, and disinfectant curve. The fouling behavior of UF membrane was comprehensively analyzed especially in terms of pollutant removal and fouling reversibility to understand the mechanism of fouling accumulation and disinfectant dose reduction. Pre-coagulation with or without adsorption both achieved remarkable effect of fouling mitigation and disinfection dose reduction. The two pretreatments were effective in total fouling control and pre-coagulation combined with PAC adsorption even decreased hydraulically irreversible fouling notably. Besides, pre-coagulation decreased residual disinfectant decline due to the removal of hydrophobic components of natural organic matters (NOM). Pre-coagulation combined with adsorption had a synergistic effect on further disinfectant decline rate reduction and decreased total disinfectant consumption due to additional removal of hydrophilic NOM by PAC adsorption. The disinfectant demand was further reduced after membrane. These results show that membrane fouling and disinfectant dose can be reduced in UF coupled with pretreatment, which could lead to the avoidance of excessive operation cost disinfectant dose for drinking water supply.

Comparing peracetic acid and hypochlorite for disinfection of combined sewer overflows: Effects of suspended-solids and pH.

Science.gov (United States)

McFadden, M; Loconsole, J; Schockling, A J; Nerenberg, R; Pavissich, J P

2017-12-01

Peracetic acid (PAA) is an alternative disinfectant that may be effective for combined sewer overflow (CSO) disinfection, but little is known about the effect of particle size on PAA disinfection efficiency. In this work, PAA and hypochlorite were compared as disinfectants, with a focus on the effect of wastewater particles. Inactivation experiments were conducted on suspended cultures of Escherichia coli and wastewater suspended solids. Tested size fractions included particle diameters disinfection efficiency decreased with increasing solids size. However, solids size had little effect on PAA disinfection. The PAA disinfection efficiency decreased at pH values above 7.5. Live/dead staining revealed that PAA disinfection leaves most cells in a viable but non-culturable condition. Fourier transform infrared spectroscopy (FTIR) analyses suggests that PAA and hypochlorite may inactivate E. coli bacteria by similar mechanisms. Copyright © 2017 Elsevier B.V. All rights reserved.

Disinfection byproduct formation from chlorination of pure bacterial cells and pipeline biofilms.

Science.gov (United States)

Wang, Jun-Jian; Liu, Xin; Ng, Tsz Wai; Xiao, Jie-Wen; Chow, Alex T; Wong, Po Keung

2013-05-15

Disinfection byproduct (DBP) formation is commonly attributed to the reaction between natural organic matters and disinfectants, yet few have considered the contribution from disinfecting bacterial materials - the essential process of water disinfection. Here, we explored the DBP formation from chlorination and chloramination of Escherichia coli and found that most selected DBPs were detectable, including trihalomethanes, haloacetonitriles, chloral hydrate, chloropicrin, and 1,1,1-trichloro-2-propanone. A positive correlation (P = 0.08-0.09) between DBP formation and the log reduction of E. coli implied that breaking down of bacterial cells released precursors for DBP formation. As Pseudomonas aeruginosa is a dominant bacterial species in pipeline biofilms, the DBP formation potentials (DBPFPs) from its planktonic cells and biofilms were characterized. Planktonic cells formed 7-11 times greater trihalomethanes per carbon of those from biofilms but significantly lower (P biofilms on polyvinyl chloride compared to that on galvanized zinc. This study revealed both the in situ disinfection of bacterial planktonic cells in source water and ex situ reaction between biofilms and residual chlorine in pipeline networks as hitherto unknown DBP sources in drinking water. Copyright © 2013 Elsevier Ltd. All rights reserved.

Selection Criteria for Water Disinfection Techniques in Agricultural Practices

OpenAIRE

Haute, Sam van; Sampers, Imca; Jacxsens, Liesbeth; Uyttendaele, Mieke

2013-01-01

This paper comprises a selection tool for water disinfection methods for fresh produce pre- and postharvest practices. A variety of water disinfection technologies is available on the market and no single technology is the best choice for all applications. It can be difficult for end users to choose the technology that is best fit for a specific application. Therefore, the different technologies were characterized in order to identify criteria that influence the suitability of a technology fo...

A novel cupping-assisted plasma treatment for skin disinfection

Science.gov (United States)

Xiong, Zilan; Graves, David B.

2017-02-01

A novel plasma treatment method/plasma source called cupping-assisted plasma treatment/source for skin disinfection is introduced. The idea combines ancient Chinese ‘cupping’ technology with plasma sources to generate active plasma inside an isolated, pressure-controlled chamber attached to the skin. Advantages of lower pressure include reducing the threshold voltage for plasma ignition and improving the spatial uniformity of the plasma treatment. In addition, with reduced pressure inside the cup, skin pore permeability might be increased and it improves attachment of the plasma device to the skin. Moreover, at a given pressure, plasma-generated active species are restricted inside the cup, raising local reactive species concentration and enhancing the measured surface disinfection rate. A surface micro-discharge (SMD) device is used as an example of a working plasma source. We report discharge characteristics and disinfection efficiency as a function of pressure and applied voltage.

[The effect of disinfectant soaking on dental gypsum model size].

Science.gov (United States)

Zhu, Cao-yun; Xu, Yun-wen; Xu, Kan

2012-12-01

To study the influence of disinfectant soaking on the dimensional stability of three kinds of dental gypsum model. Three commonly used gypsums ( type III,IV,Vtype) in clinic were used to make 24 specimens for 50 mm×15 mm×10 mm in size. One hour after release, the specimens were placed for 24 h. A digital caliper was used to measure the size of the gypsum model. Distilled water immersion was as used control, glutaraldehyde disinfectant and Metrix CaviCide disinfectant soaking were used for the experimental group. After soaking for 0.5h, the gypsum models were removed and placed for 0.5 h, 1 h, 2 h, 24 h. The size of the models was measured again using the same method. The data was analyzed with SPSS10.0 software package. The initial gypsum model length was (50.07±0.017) mm, (50.048±0.015) mm and (50.027±0.015) mm. After soaking for different times, the size of the model changed little, and the dimensions changed less than 0.01%. The results show that disinfectant soaking has no significant effect on dental model dimensions.

Enhancement of ultraviolet water disinfection process

African Journals Online (AJOL)

grabi-1

2013-05-15

May 15, 2013 ... disinfected water distribution systems, including. Legionella .... soft agar, mixed, incubated at room temperature for 2 min and poured onto the ... The determination of a log increase methodology was employed to quantify the ...

Dimensional Stability of Color-Changing Irreversible Hydrocolloids after Disinfection

Directory of Open Access Journals (Sweden)

Khaledi AAR

2015-03-01

Full Text Available Statement of Problem: Disinfection of dental impressions is a weak point in the dental hygiene chain. In addition, dental office personnel and dental technicians are endangered by cross-contamination. Objectives: This study aimed to investigate the dimensional stability of two color-changing irreversible hydrocolloid materials (IH after disinfection with glutaraldehyde. Materials and Methods: In this in vitro study, impressions were made of a master maxillary arch containing three reference inserts on the occlucal surface of the left and right maxillary second molars and in the incisal surface of the maxillary central incisors. Two types of color-changing irreversible hydrocolloid (tetrachrom, cavex were used. Glutaraldehyde 2% was used in two methods of spraying and immersion to disinfect the impressions. The control group was not disinfected. Casts were made of type IV gypsum. The linear dimensional change of the stone casts was measured with a profile projector. For statistical analysis, Kruskall-Wallis and Mann-Witney tests were used (α=0.05. Results: By immersion method, the casts fabricated from tetrachrom were 0.36% larger in the anteroposterior (AP and 0.05% smaller in cross arch (CA dimensions; however, the casts prepared after spraying of tetrachrom were 0.44% larger in the AP and 0.10% smaller in CA dimensions. The casts made from Cavex were 0.05% smaller in the AP and 0.02% smaller in CA dimensions after spraying and 0.01% smaller in the AP and 0.003% smaller in CA dimensions after immersion. Generally there were not significant differences in AP and CA dimensions of the experimental groups compared to the control (p > 0.05. Conclusions: Disinfection of the tested color-changing irreversible hydrocolloids by glutaraldahyde 2% did not compromise the accuracy of the obtained casts.

Comparison of antimicrobial activities and compressive strength of alginate impression materials following disinfection procedure.

Science.gov (United States)

Alwahab, Zahraa

2012-07-01

This study investigated the effectiveness of disinfecting solution when incorporated into alginate powder instead of water against some microorganisms and on compressive strength of alginate. For measuring antimicrobial activity of alginate, 60 alginate specimens were prepared and divided into two groups: One with water incorporated in the mix (control) and the other with 0.2% chlorhexidine digluconate incorporated in the mix instead of water. The tested microorganisms were: gram +ve cocci, gram -ve bacilli and yeast (each group 10 samples). For measuring compressive strength, 20 specimens of alginate were divided into two groups: One with water incorporated in the mix (control) and the other with chlorhexidine incorporated in the mix. The statistical analysis of antimicrobial efficacy of alginate was performed with Mann-Whitney U-test, which revealed very high significant difference when comparing among groups (p 0.05). The incorporation of disinfecting agents into impression materials could serve an important role in dental laboratory infection control and it had no adverse effect on compressive strength of the hydrocolloid alginate. The risk of transmitting pathogenic microorganisms to dental laboratories via impression has been considered a topic of importance for a number of years.

Enhanced coagulation with powdered activated carbon or MIEX secondary treatment: a comparison of disinfection by-product formation and precursor removal.

Science.gov (United States)

Watson, Kalinda; Farré, Maria José; Knight, Nicole

2015-01-01

The removal of both organic and inorganic disinfection by-product (DBP) precursors prior to disinfection is important in mitigating DBP formation, with halide removal being particularly important in salinity-impacted water sources. A matrix of waters of variable alkalinity, halide concentration and dissolved organic carbon (DOC) concentration were treated with enhanced coagulation (EC) followed by anion exchange (MIEX resin) or powdered activated carbon (PAC) and the subsequent disinfection by-product formation potentials (DBP-FPs) assessed and compared to DBP-FPs for untreated samples. Halide and DOC removal were also monitored for both treatment processes. Bromide and iodide adsorption by MIEX treatment ranged from 0 to 53% and 4-78%, respectively. As expected, EC and PAC treatments did not remove halides. DOC removal by EC/PAC was 70 ± 10%, while EC/MIEX enabled a DOC removal of 66 ± 12%. Despite the halide removals achieved by MIEX, increases in brominated disinfection by-product (Br-DBP) formation were observed relative to untreated samples, when favourable Br:DOC ratios were created by the treatment. However, the increases in formation were less than what was observed for the EC/PAC treated waters, which caused large increases in Br-DBP formation when high Br-DBP-forming water quality conditions occurred. The formation potential of fully chlorinated DBPs decreased after treatment in all cases.

The Occurrence and Comparative Toxicity of Haloacetaldehyde Disinfection Byproducts in Drinking Water

Science.gov (United States)

The introduction of drinking water disinfection greatly reduced the incidence of waterborne diseases. However, the reaction between disinfectants and natural organic matter in the source water can lead to an unintended consequence, which is the formation of drinking water disinfe...

Comparing Peracetic Acid with Sodium Hypochlorite for Disinfection of Combined Sewer Overflows

Science.gov (United States)

This cooperative research and development agreement between U.S. EPA, Solvay, MSDGC, and CB&I is evaluating the potential of PAA for disinfection of Muddy Creek CSO wastewater and comparing that with sodium hypochlorite disinfection. This presentation will document the effective...

Disinfection of indoor air microorganisms in stack room of university library using gaseous chlorine dioxide.

Science.gov (United States)

Hsu, Ching-Shan; Lu, Ming-Chun; Huang, Da-Ji

2015-02-01

As with all indoor public spaces in Taiwan, the stack rooms in public libraries should meet the air quality guidelines laid down by the Taiwan Environmental Protection Administration. Accordingly, utilizing a university library in Taiwan for experimental purposes, this study investigates the efficiency of gaseous chlorine dioxide (ClO2) as a disinfection agent when applied using three different treatment modes, namely a single-daily disinfection mode (SIM), a twice-daily disinfection mode (TWM), and a triple-daily disinfection mode (TRM). For each treatment mode, the ClO2 is applied using an ultrasonic aerosol device and is performed both under natural lighting conditions and under artificial lighting conditions. The indoor air quality is evaluated before and after each treatment session by measuring the bioaerosol levels of bacteria and fungi. The results show that for all three disinfection modes, the application of ClO2 reduces the indoor bacteria and fungi concentrations to levels lower than those specified by the Taiwan EPA (i.e., bacteria <1500 CFU/m(3), fungi <1000 CFU/m(3)), irrespective of the lighting conditions under which the disinfection process is performed. For each disinfection mode, a better disinfection efficiency is obtained under natural lighting conditions since ClO2 readily decomposes under strong luminance levels. Among the three treatment modes, the disinfection efficiencies of the TWM and TRM modes are very similar under natural lighting conditions and are significantly better than that of the SIM mode. Thus, overall, the results suggest that the TWM treatment protocol represents the most cost-effective and efficient method for meeting the indoor air quality requirements of the Taiwan EPA.

The effect of various disinfectants on dental shade guides.

Science.gov (United States)

Huang, Peterson Y; Masri, Radi; Romberg, Elaine; Driscoll, Carl F

2014-09-01

Dental shade guides are used to evaluate tooth color before prosthodontic procedures and are subjected to disinfection after use. The effect of disinfection on shade guides has not been thoroughly investigated. The purpose of this study was to evaluate the effect of disinfectants on the color of shade tabs. Changes in the color (ΔE) of VITA Classical Shade Guide tabs were measured with a VITA Easyshade spectrophotometer in the CIELAB system and calculated after being subjected to Cavicide, Asepticare TB, Sporicidin, and distilled water (control) over a simulated period of 2 years. Statistical analysis was accomplished by a 2-way analysis of variance followed by the Tukey honestly significant difference (HSD) test (α=.05). A significant difference was noted in the degree of shade tab color change, depending on the type of disinfectant used (F=153.2, PCavicide (ΔE=1.198). The average total CIELAB color difference for 50% human perceptibility is approximately 1 unit (under standardized laboratory conditions). In the oral cavity, however, an average change of 3.7 ΔE units could still allow teeth to be perceived as having the same color. Therefore, although the results are statistically significant, they may not be clinically important. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Moist Heat Disinfection and Revisiting the A0 Concept.

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McCormick, Patrick J; Schoene, Michael J; Dehmler, Matthew A; McDonnell, Gerald

2016-04-02

Moist heat is employed in the medical device, pharmaceutical, and food processing industries to render products and goods safe for use and human consumption. Applications include its use to pasteurize a broad range of foods and beverages, the control of microbial contamination of blood products, and treatment of bone tissue transplants and vaccines. In the pharmaceutical industry, water heated to 65°C to 80°C is used to sanitize high-purity water systems. In healthcare, it has been employed for decades to disinfect patient care items ranging from bedpans to anesthesia equipment. There is a good understanding of the conditions necessary to achieve disinfection of microorganisms at temperatures ranging from 65°C to 100°C. Based on this information, the efficacy of moist heat processes at a range of exposure times and temperatures can be quantified based on mathematical models such as the A0 calculation. While the A0 concept is recognized within the European healthcare community, it has yet to be widely adopted within the United States. This article provides information regarding the A0 concept, a brief overview of the classification of thermal disinfection for use with healthcare applications within the United States, and recent data on reinvestigating the thermal disinfection of a selected panel of microorganisms and a mixed culture biofilm.

Effects of immersion disinfection of agar-alginate combined impressions on the surface properties of stone casts.

Science.gov (United States)

Iwasaki, Yukiko; Hiraguchi, Hisako; Iwasaki, Eriko; Yoneyama, Takayuki

2016-01-01

This study investigated the effects of disinfection of agar-alginate combined impressions on the surface properties of the resulting stone casts. Two brands of cartridge-form agar impression material and one alginate impression material were used. Agar-alginate combined impressions of smooth glass plates were prepared. The impressions were immersed in 0.55% ortho-phthalaldehyde solution or 0.5% sodium hypochlorite solution for 1, 3, 5 and 10 min. A stone cast made with an impression that had not been immersed was prepared as a control. The surface roughness (Ra) of the stone casts was measured, and the cast surfaces were observed by SEM. Immersion of agar-alginate combined impressions in 0.5% sodium hypochlorite solution for up to 10 min had no serious adverse effects on the surface properties of the stone casts. In contrast, even 1 min of immersion in 0.55% ortho-phthalaldehyde solution caused deterioration of the cast surface properties.

In Vitro Evaluation of Dimensional Stability of Alginate Impressions after Disinfection by Spray and Immersion Methods

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Fahimeh Hamedi Rad

2010-12-01

Full Text Available Background and aims. The most common method for alginate impression disinfection is spraying it with disinfecting agents, but some studies have shown that these impressions can be immersed, too. The aim of this study was to evaluate the dimensional stability of alginate impressions following disinfecting by spray and immersion methods. Materials and methods. Four common disinfecting agents (Sodium Hypochlorite, Micro 10, Glutaraldehyde and Deconex were selected and the impressions (n=108 were divided into four groups (n=24 and eight subgroups (n=12 for disinfecting by any of the four above-mentioned agents by spray or immersion methods. The control group (n=12 was not disinfected. Then the impressions were poured by type III Dental Stone Plaster in a standard method. The results were analyzed by descriptive methods (mean and standard deviation, t-test, two-way analysis of variance (ANOVA and Duncan test, using SPSS 14.0 software for windows. Results. The mean changes of length and height were significant between the various groups and disinfecting methods. Regarding the length, the greatest and the least amounts were related to Deconex and Micro 10 in the immersion method, respectively. Regarding height, the greatest and the least amounts were related to Glutaraldehyde and Deconex in the immersion method, respectively. Conclusion. Disinfecting alginate impressions by Sodium Hypochlorite, Deconex and Glutaraldehyde by immersion method is not recommended and it is better to disinfect alginate impressions by spraying of Micro 10, Sodium Hypochlorite, Glutaraldehyde and immersion in Micro 10.

Evaluation of toothbrush disinfection via different methods

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Adil BASMAN

2016-01-01

Full Text Available The aim of this study was to compare the efficacy of using a dishwasher or different chemical agents, including 0.12% chlorhexidine gluconate, 2% sodium hypochlorite (NaOCl, a mouthrinse containing essential oils and alcohol, and 50% white vinegar, for toothbrush disinfection. Sixty volunteers were divided into five experimental groups and one control group (n = 10. Participants brushed their teeth using toothbrushes with standard bristles, and they disinfected the toothbrushes according to instructed methods. Bacterial contamination of the toothbrushes was compared between the experimental groups and the control group. Data were analyzed by Kruskal–Wallis and Duncan's multiple range tests, with 95% confidence intervals for multiple comparisons. Bacterial contamination of toothbrushes from individuals in the experimental groups differed from those in the control group (p < 0.05. The most effective method for elimination of all tested bacterial species was 50% white vinegar, followed in order by 2% NaOCl, mouthrinse containing essential oils and alcohol, 0.12% chlorhexidine gluconate, dishwasher use, and tap water (control. The results of this study show that the most effective method for disinfecting toothbrushes was submersion in 50% white vinegar, which is cost-effective, easy to access, and appropriate for household use.

Solar disinfection of water for low income communities; Desinfeccao solar de agua para comunidades de baixa renda