Dilute Bleach Solution Research Articles

Evaluation of the effects of repeated disinfection on medical exam gloves: Part 1. Changes in physical integrity

COVID-19 has created shortages of personal protective equipment. In resource-constrained situations, limited cycles of disinfection and extended use of gloves is recommended by the U.S. Centers for Disease Control and Prevention to conserve supplies. However, these guidelines are based on limited evidence. In this study, serial cycles of hand hygiene were performed on gloved hands using an ethanol-based hand rub (six and 10 cycles), 0.1% sodium hypochlorite (bleach) solution (10 cycles), or soap and water (10 cycles) on latex and nitrile medical exam gloves from the United States and India. A modified water-leak test evaluated glove integrity after repeated applications of these disinfecting agents. When aggregated, dilute bleach demonstrated the lowest difference between treatment and control arms: −2.5 percentage points (95% CI: −5.3 to 0.3) for nitrile, 0.6 percentage points (95% CI: −2.6 to 3.8) for non-powdered latex. For U.S.-purchased gloves tested with six and 10 applications of ethanol-based hand rub, the mean difference in failure risk between treatment and control gloves was within the prespecified non-inferiority margin of five percentage points or less, though some findings were inconclusive since outside the margin. The aggregated difference in failure risk between treatment and control was 3.5 percentage points (0.6 to 6.4) for soap and water, and 2.3 percentage points (−0.5 to 5.0) and 5.0 percentage points (1.8 to 8.2) for 10 and 6 applications of ethanol-based hand rub, respectively. Most leaks occurred in the interdigital webs (35%) and on the fingers (34%). This indicates that some combinations of glove types and disinfection methods may allow for extended use. Ten applications of dilute bleach solution had the least impact on glove integrity. However, the majority of glove and exposure combinations were inconclusive. Additional testing of specific glove and disinfectant combinations may inform future strategies to guide extended use during glove shortages. Additional considerations, not evaluated here, include duration of use, disinfectant chemical permeation, and the effects of hand temperature, movement, and manipulation of instruments on glove integrity.

Bird-feeder cleaning lowers disease severity in rural but not urban birds

Animals inhabiting urban areas often experience elevated disease threats, putatively due to factors such as increased population density and horizontal transmission or decreased immunity (e.g. due to nutrition, pollution, stress). However, for animals that take advantage of human food subsidies, like feeder-visiting birds, an additional mechanism may include exposure to contaminated feeders as fomites. There are some published associations between bird feeder presence/density and avian disease, but to date no experimental study has tested the hypothesis that feeder contamination can directly impact disease status of visiting birds, especially in relation to the population of origin (i.e. urban v. rural, where feeder use/densities naturally vary dramatically). Here we used a field, feeder-cleaning experimental design to show that rural, but not urban, house finches (Haemorhous mexicanus) showed increased infection from a common coccidian endoparasite (Isospora spp.) when feeders were left uncleaned and that daily cleaning (with diluted bleach solution) over a 5-week period successfully decreased parasite burden. Moreover, this pattern in rural finches was true for males but not females. These experimental results reveal habitat- and sex-specific harmful effects of bird feeder use (i.e. when uncleaned in rural areas). Our study is the first to directly indicate to humans who maintain feeders for granivorous birds that routine cleaning can be critical for ensuring the health and viability of visiting avian species.

Enhancing antibacterial and flame-retardant performance of cotton fabric with an iminodiacetic acid-containing N-halamine

This research focused on preparing antibacterial and flame-retardant multifunctional cotton fabric to decrease the threat of harmful microorganism and fire, which might have huge potential application in household textiles. A water-soluble N-halamine precursor based on s-triazine (TIAPC) was synthesized by introducing iminodiacetic acid (IDA), which can chelate with metal ions to obtain flame retardancy. After coating with TIAPC, the cotton fabric was chlorinated in dilute bleach solution and chelated in metal salt solution to achieve antibacterial and flame-retardant properties. The surface morphology and chemical state of TIAPC-coated cotton fabric were characterized by FT-IR, XPS, SEM and EDX. The chlorinated TIAPC-coated cotton fabric displayed high-efficacy and rapid bactericidal effect against S. aureus and E. coli O157: H7 with 100% bacterial reduction in 1 min. Meanwhile, the chelated TIAPC-modified cotton fabric presented good thermal stability and char-forming capability. The hydrophobic property of modified cotton fabric was greatly improved after chlorination. Besides, this multifunctional coating had little effect on the cytotoxicity, tensile strength, air permeability, whiteness and drape of cotton fabric.

Stable N-halamine on polydopamine coating for high antimicrobial efficiency

In this paper, we report a simple method for preparing a highly effective antibacterial coating by the introduction of an N-halamine structure on a polydopamine (PDA)-based coating. The PDA-based coating includes only PDA and PDA co-deposited with polyethylenimine (PEI). The amine groups in PDA and PEI are assumed to be chlorinated and converted to N-halamine. After the simple immersion of PDA-based coatings in a dilute bleach solution, the formation of N-halamine is confirmed by iodometric titration. Compared with the original PDA-based coating, N-halamine-functionalized PDA-based coatings exhibit high antibacterial activity toward Gram-positive S. aureus and Gram-negative E. coli within a brief contact time. Notably, the PDA samples retain their oxidative chlorine content after extended storage, and ~90% of the chlorine is restorable after repeated quenching. The coatings are applicable to a wide spectrum of substrates and are stable. This study may provide a simple, effective method for the preparation of functional fibers with antibacterial activities for the clothing and textile industries.

Infection control in residential care homes for the elderly in Hong Kong (2005-2014).

This serial cross-sectional survey study aimed to review the trend in various infection control practices in residential care homes for the elderly (RCHEs) in Hong Kong from 2005 to 2014. Annual cross-sectional surveys were conducted at all RCHEs in Hong Kong, including self-administered questionnaires, on-site interviews, inspections, and assessments conducted by trained nurses, from 2005 to 2014. In all, 98.5% to 100% of all RCHEs were surveyed each year based on the list of licensed RCHEs in Hong Kong. There was a substantial increase in the proportion of RCHE residents aged ≥85 years, from 40.0% in 2005 to 50.2% in 2014 (P=0.002). The percentage of RCHE residents with special care needs also increased, from 22.3% in 2005 to 32.6% in 2014 for residents with dementia (P<0.001) and from 3.4% in 2005 to 5.0% in 2014 for residents with a long-term indwelling urinary catheter (P<0.001). The proportion of RCHEs with separate rooms for isolation areas ranged from 73.6% to 80% but did not show any significant trend over the study period. The proportion of RCHEs with alcohol hand rub available showed an increasing trend from 25.4% in 2006 to 99.2% in 2014 (P=0.008). The proportion of health or care workers (who were not the designated infection control officers) passing skills tests on hand washing techniques increased from 79.2% in 2006 to 91.5% in 2014 (P=0.02). An increasing trend was also observed for the proportion of infection control officers who were able to prepare properly diluted bleach solution, from 71.5% in 2005 to 92.2% in 2014 (P=0.002). For infection control practice to continue improving, more effort should be made to enhance and maintain proper practice, and to mitigate the challenge posed by the high turnover rates of healthcare workers in RCHEs. Introduction of self-audits on infection control practices should be considered.

Diluted sodium hypochlorite (bleach) in dogs: antiseptic efficacy, local tolerability and in vitro effect on skin barrier function and inflammation.

Diluted sodium hypochlorite represents an inexpensive and widely available topical antiseptic, but there are no tolerability and efficacy data in veterinary dermatology. To determine the in vivo antibacterial effect and tolerability of topical diluted bleach application and to assess its in vitro effect on skin barrier lipids and anti-inflammatory properties on keratinocytes. Topical hypochlorite at 0.05% and tap water were applied to both sides of the thorax of four healthy dogs. The anti-inflammatory effect on canine keratinocytes was determined by real-time polymerase chain reaction; skin barrier integrity was assessed by evaluating stratum corneum lipid changes in canine stratified epidermal constructs. The cell viability of primary keratinocytes treated with water and diluted hypochlorite at 0.005 and 0.01%, reduced the percentage of viable cells by 10%. The exposure of primary keratinocytes to 0.005% diluted hypochlorite significantly reduced the induction of inflammatory genes chemokine ligand-2 (CCL2; P = 0.015) and thymus and activation-regulated chemokine (TARC/CCL17, P = 0.032). There were no changes in skin lipid ceramide and nonceramide fractions in stratified epidermal constructs cultured for 17 days with 0.05% hypochlorite. Topical hypochlorite at 0.05% and tap water were well-tolerated without signs of skin irritation. Although a marked reduction in bacterial counts was seen within 20 min of diluted bleach application compared to the tap water control, this was only marginally significant (P = 0.06). The results indicate that a topical diluted bleach solution, at either 0.05 or 0.005% hypochlorite concentrations, is a well-tolerated antiseptic that also exhibits anti-inflammatory properties.

Synthesis and application to cellulose of reactive dye precursor of anti‐bacterial N‐halamine

To achieve textile dyeing and functional finishing in one process, a bleach‐resistant reactive dye precursor to anti‐bacterial N‐halamine was synthesised by reacting a type of dichlorotriazine reactive dye with 4‐amino‐2,2,6,6‐tetramethylpiperidine. The synthesised compound, which can be transformed to an N‐halamine molecule by exposure to dilute bleach solution, was used to dye cotton fabrics. After exposure to a dilute sodium hypochlorite solution, dyed cotton fabrics showed excellent anti‐bacterial properties against Staphylococcus aureus and Escherichia coli O157:H7, facilitating a ca. 6‐log reduction in bacteria within a short period of contact. Compared with the dichlorotriazine reactive dye, the reactive dye precursor demonstrated comparable dyeing properties including exhaustion and fixation values. No differences in rub fastness, wash fastness or bleach fastness were detected between fabrics dyed with, respectively, dichlorotriazine reactive dye and the reactive dye precursor to N‐halamine.

Antimicrobial silica and sand particles functionalized with an N‐halamine acrylamidesiloxane copolymer

ABSTRACTThe monomer 2‐acrylamido‐2‐methyl‐1‐(5‐methylhydantoinyl)propane (HA) was copolymerized with 3‐(trimethoxysilyl)propyl methacrylate (SL) and covalently attached onto silica gel and sand particles. As a result HASL copolymer‐grafted silica gel and sand particles (HASL SGPs and SPs) were obtained. These two types of HASL SGPs and SPs provided excellent biocidal efficacy against Gram positive S. aureus and Gram negative E. coli O157:H7 bacteria when the copolymer‐grafted particles were exposed to dilute sodium hypochlorite (household bleach) solution. In a flowing water application, seven logs of bacteria were inactivated within 10 s of contact time with the particles packed into a column. The treated particles also exhibited good washing and storage stabilities. The chlorine loss during extensive flow could be recovered by further exposure to dilute bleach solution. The antimicrobial particles have potential application for use in inexpensive disinfecting water filters for slow water flows. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43413.

Antimicrobial N‐halamine coatings synthesized via vapor‐phase assisted polymerization

ABSTRACTAn N‐halamine monomer, 3‐allyl‐5,5‐dimethylhydantoin (ADMH), was synthesized by a Gabriel reaction of 5,5‐dimethylhydantoin and 3‐bromopropene. Antimicrobial coatings of poly[1‐(4,4‐dimethyl‐2,5‐dioxoimidazolidin‐1‐methyl)ethylene] were prepared on plasma‐treated PET fabrics via a vapor‐phase assisted polymerization (VAP) process using gasified ADMH as monomer. The coatings endow the PET fabrics with an antimicrobial efficiency greater than 80% for both Escherichia coli and Staphylococcus aureus after chlorination of the N‐halamine polymer with dilute bleach solution. The obtained antimicrobial effect has remarkable durability that can bear over 30 times of stringent laundering tests. Compared with other antimicrobial finishing methods, the VAP methodology offers great advantages in needless of organic solvents and small consumption of monomer. It has potential applications in a wide variety of fields such as hygienic clothing, underwear, socks, and medical textiles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41824.

Efficacy of Dilute Hypochlorite Solutions and an Electrochemically Activated Saline Solution Containing Hypochlorous Acid for Disinfection of Methicillin-Resistant Staphylococcus aureus in a Pig Skin Model

Recurrent skin and soft-tissue infections (SSTIs) due to Staphylococcus aureus are a common problem in children and adults. Many of these SSTIs are caused by a community-associated methicillin-resistant S. aureus (MRSA) strain designated USA300. Dilute bleach baths are commonly used as part of decolonization regimens for recurrent SSTI, particularly in children. However, limited data are available on the microbiological efficacy of dilute bleach on skin, and optimal concentrations are unknown. Recent practice guidelines for MRSA from the Infectious Diseases Society of America recommend a teaspoon of household bleach per gallon of bath water (1.3 μL/mL or a quarter cup per quarter tub of water) for 15 minutes twice weekly. On the basis of in vitro data, Fisher et al suggested that a higher concentration (2.5 μL/mL or a half cup per quarter tub of water) might be more effective (more than a 3-log reduction in MRSA in 5 minutes versus a 2-log reduction for a 1.2-μL/mL concentration). In contrast, more dilute bleach solutions (eg, a quarter cup of 6% sodium hypochlorite per bathtub full of water) for 5 days in combination with intranasal mupirocin were effective for eradication of colonization in a recent randomized trial, but 29% of patients in the mupirocin/bleach bath group developed recurrent colonization within 4 months. Here, we used a pig skin model to examine the effectiveness of various concentrations of dilute bleach solution and an electrochemically activated saline solution containing 0.025% hypochlorous acid (Vashe; PuriCore) for disinfection of MRSA on skin. Vashe is safe for use on skin and is commercially available as a wound care product.

The Long Road to Recovery: Environmental Health Impacts of Hurricane Sandy

Building contractor John Pierciey stands in the gutted interior of a 1950s-era home in Manasquan, New Jersey. Wallboard, two layers of wood flooring, a layer of felt—all of it had to be ripped out to rid the house of mold caused by Hurricane Sandy’s storm surge. “This is the sixth house I’ve gutted in a week,” Pierciey says. “Every one is different. You don’t know what you’re going to find until you take them apart.” Residents and volunteers keep warm by a fire barrel in the New Dorp Beach neighborhood of Staten Island, 5 November 2012. Power outages persisted through a cold snap that put temperatures in the single digits. So it is with the environmental health impacts of Hurricane Sandy. Every layer of society, every type of building, has felt the impact of the storm, which struck the U.S. East Coast on 29 October 2012. Incidences of death and illness, though small in number compared with some storms, have come in many forms, the effects still unfolding as time goes by.

Sporicidal/Bactericidal Textiles via the Chlorination of Silk

Bacterial spores, such as those of the Bacillus genus, are extremely resilient, being able to germinate into metabolically active cells after withstanding harsh environmental conditions or aggressive chemical treatments. The toughness of the bacterial spore in combination with the use of spores, such as those of Bacillus anthracis, as a biological warfare agent necessitates the development of new antimicrobial textiles. In this work, a route to the production of fabrics that kill bacterial spores and cells within minutes of exposure is described. Utilizing this facile process, unmodified silk cloth is reacted with a diluted bleach solution, rinsed with water, and dried. The chlorination of silk was explored under basic (pH 11) and slightly acidic (pH 5) conditions. Chloramine-silk textiles prepared in acidified bleach solutions were found to have superior breaking strength and higher oxidative Cl contents than those prepared under caustic conditions. Silk cloth chlorinated for ≥1 h at pH 5 was determined to induce >99.99996% reduction in the colony forming units of Escherichia coli, as well as Bacillus thuringiensis Al Hakam (B. anthracis simulant) spores and cells within 10 min of contact. The processing conditions presented for silk fabric in this study are highly expeditionary, allowing for the on-site production of protein-based antimicrobial materials from a variety of agriculturally produced feed-stocks.

Efficacy of a Diluted Bleach Solution Against Clostridium difficile Spores

Efficacy of a Diluted Bleach Solution Against Clostridium difficile Spores

Care of Patients with Long-Term Indwelling Urinary Catheters

The complications and management of long-term indwelling catheters used for urinary retention and incontinence were reviewed. Research evidence from 1992 – 2002 was located through searches of CINAHL (38 articles), and Medline (89 articles). Fifty studies were critiqued for this review. The most common complications of long-term indwelling catheters are bacteriuria, encrustation, and blockage. Less common is the prevalence of bacteremia and renal disease. Risk factors for bacteriuria include female gender, older age, and long-term indwelling catheter use. Urinary white blood cells are the best indicator of urinary tract infection. For drainable catheter systems used by community dwelling adults, daily bag cleaning with a diluted bleach solution (1:10) is effective in reducing bacterial counts to negligible numbers. Application of topical antibiotic cream to the meatus around the catheter does not reduce bacteriuria. Silicone catheters and larger lumen size catheters are more resistant to encrustation than other catheter types and smaller lumen size catheters. Acidifying the urine without removing the urease-producing bacteria does not reduce encrustation. Removal of catheter blockage is preventive for renal disease. Because of the complications of long-term indwelling catheter usage, periodic assessment and voiding trials should be used to determine the continued need for a catheter. Evidence-based recommendations for managing indwelling urinary catheters include screening for risk factors and evaluating urinary white blood cell count for infection, and assessment of the continued need for a catheter. Interventions include consideration of closed versus open drainage systems, type of catheter, and size of catheter lumen.

Starch–Iodide Swab Technique for Detecting Bleach-Dipped Female Lobsters

Abstract The illegal removal of eggs from female American lobsters Homarus americanus is a major problem in the lobster industry. Dipping female egg-bearing lobsters in a dilute bleach solution to remove the eggs has been used by some in the lobster industry to make these lobsters appear marketable. Because this dipping leaves only a trace amount of bleach, it has escaped detection by conventional methods. We developed a simple, noninvasive technique for detecting the presence of small amounts of bleach on lobsters. Cotton swabs dipped in a starch–iodide solution turned blue when rubbed on the tails of bleach-dipped lobsters. Swabs rubbed on nonbleached control lobster tails did not change color. A validation study showed that this method took about 5–10 s for each lobster and consistently stained all the bleach-dipped lobsters with no false positives. This technique is ready to be implemented by law enforcement officials to monitor and protect the American lobster population.

The inner voice

Laboratories and clinics that collect airflow data typically use either a standard pneumotachograph or the Rothenberg face mask. Because subjects and patients breathe through these masks and because these masks come into contact with skin, some procedure should be followed to prevent cross infection. Sterilization is not required since the masks do not normally come into contact with mucous membranes or the blood stream or other body fluids. However, simple procedures for disinfecting the masks should be followed to reduce or eliminate the risk of transmission of air-borne organisms and/or skin problems. Occasionally, saliva and/or sputum collect on the mask surfaces. These should be removed before the mask is disinfected. Rutala (1990) has described guidelines for infection control as adopted by the Association for Practitioners in Infection Control (APIC). Disinfection refers to procedures designed to eliminate many or all microorganisms with the exception of bacterial spores. There are three levels of disinfection. High level disinfection refers to items that come into contact with mucous membranes or nonintact skin. It is designed to destroy all microorganisms with the exception of bacterial spores in large concentrations. Intermediate level includes items such as bedpans, blood pressure cuffs, linens, utensils etc. At this level, vegetative bacteria, most viruses and fungi are eliminated but it does not kill bacterial spores. Low level items are those that come into contact with intact skin. Low level disinfection kills most bacteria, some viruses and some fungi. There are several potential chemical agents which can be used to disinfect smooth, hard-surfaced noncritical items, such as respiratory face masks. These agents include ethyl or isopropyl alcohol (at least 70%), sodium hypochlorite, iodophor germicidal solutions, or quaternary ammonium solutions. The latter three agents may be harmful to the cushion and/or wire mesh of the Rothenberg mask. Because they are potentially flammable, alcohols can be dangerous to use on a routine basis. Sodium hypochlorite is present in household bleach and although it should be handled with care, it can be an inexpensive and effective disinfectant. I t is also possible to use solutions designed for higher level disinfection such as glutaraldehyde, a solution commonly used to disinfect the laryngoscope. We use the Rothenberg face mask for the collection of airflow data, and the Smitheran and Hixon (1981) procedure for the estimation of lung pressure. In the latter procedure, a small-length tube is used to sense the pressure in the oral cavity. This tube is disposed of after use and does not need to be disinfected. It is possible to use household bleach as a disinfectant. The bactericidal component (5.25%) of bleach is sodium hypochlorite. The bleach should be diluted to produce a concentration of about 500-1000 ppm, or approximately a 25:1 ratio. According to Rutala, it is an effective bactericide, fungicide, tuberculocide, sporicide, and virucide. The solution will lose about 50% of its effectiveness after 30 days. Thus, a sufficiently strong solution should be prepared for it to be effective at 30 days. Since bleach is inexpensive, a proper concentration could be prepared weekly. Disposable gloves should be used when handling materials to be cleaned. First, the mask is washed in a solution of warm water and liquid detergent (Hibiclens, Stuart Pharmaceuticals). This is an important step to remove any material that may have been coughed or spat on the surfaces of the mask. The rubber cushion surrounding the mask is removed and both are immersed into a diluted bleach solution for 10 minutes. The mask and cushion are then rinsed thoroughly and allowed to dry. Bleach has a very strong odor that may be especially potent in the small mask space. However, the potency of the diluted solution should produce little residual odor. Occasionally, if another subject is waiting, the mask and cushion are dried with a common hair dryer. The diluted bleach solution appeared to have no harmful effects on the various components of the mask.