Quaternary Ammonium Solutions Research Articles

In Vitro Characterization and Antiviral Susceptibility of Ophidian Serpentoviruses.

Ophidian serpentoviruses, positive-sense RNA viruses in the order Nidovirales, are important infectious agents of both captive and free-ranging reptiles. Although the clinical significance of these viruses can be variable, some serpentoviruses are pathogenic and potentially fatal in captive snakes. While serpentoviral diversity and disease potential are well documented, little is known about the fundamental properties of these viruses, including their potential host ranges, kinetics of growth, environmental stability, and susceptibility to common disinfectants and viricides. To address this, three serpentoviruses were isolated in culture from three unique PCR-positive python species: Ball python (Python regius), green tree python (Morelia viridis), and Stimson's python (Antaresia stimsoni). A median tissue culture infectious dose (TCID50) was established to characterize viral stability, growth, and susceptibility. All isolates showed an environmental stability of 10-12 days at room temperature (20 °C). While all three viruses produced variable peak titers on three different cell lines when incubated at 32 °C, none of the viruses detectably replicated at 35 °C. All viruses demonstrated a wide susceptibility to sanitizers, with 10% bleach, 2% chlorhexidine, and 70% ethanol inactivating the virus in one minute and 7% peroxide and a quaternary ammonium solution within three minutes. Of seven tested antiviral agents, remdesivir, ribavirin, and NITD-008, showed potent antiviral activity against the three viruses. Finally, the three isolates successfully infected 32 unique tissue culture cell lines representing different diverse reptile taxa and select mammals and birds as detected by epifluorescent immunostaining. This study represents the first characterization of in vitro properties of growth, stability, host range, and inactivation for a serpentovirus. The reported results provide the basis for procedures to mitigate the spread of serpentoviruses in captive snake colonies as well as identify potential non-pharmacologic and pharmacologic treatment options for ophidian serpentoviral infections.

Evaluation of Glove Performance after Decontamination.

Studies of healthcare providers doffing personal protective equipment, especially gloves, indicate that self-contamination does occur. Although generally this is not hazardous, working with particularly pathogenic organisms, such as Ebola virus and Clostridium difficile, can present a serious health risk. Decontaminating medical gloves before removal can reduce self-contamination and mitigate the spread of these types of pathogens. Also, in cases of extreme shortage, the Centers for Disease Control and Prevention (CDC) has specific recommendations for decontaminating gloves for extended use. Reuse of medical gloves is strongly discouraged by both the CDC and Food and Drug Administration. This work seeks to lay a foundation of testing to evaluate whether a decontamination method is compatible for a given glove type and material. Four potential methods of decontamination (commercial hand soap, alcohol-based hand sanitizer, commercial bleach, and quaternary ammonium solution) were tested on a variety of surgical and patient examination gloves. The method of barrier performance evaluation was ASTM D5151-19, Standard Test Method for Detection of Holes in Medical Gloves. Our results indicated that the performance of the gloves after treatment was highly dependent on the composition of the medical gloves. In general, the surgical gloves in this study performed better than the patient examination gloves, regardless of the material from which they were made. Specifically, vinyl examination gloves tended to have poorer performance. In this study, the number of gloves available to test were limited and therefore statistical significance is beyond the scope of this project.

Molecular Simulation of Quaternary Ammonium Solutions at Low Hydration Levels

Much research has focused on the stability of substituted ammonium salts in anion-exchange membranes (AEMs). While cation chemistry dictates AEM stability, chemical degradation has been recently shown to be significantly influenced by the hydration level at which the AEM operates. At low hydration, it is now known that almost every quaternary ammonium may suffer significant decomposition. In this work, we use molecular dynamics simulations to explore the behavior of three common quaternary ammonium cations with stoichiometric hydroxide concentration and at very low hydration. We find that water preferentially solvates hydroxide anions and hence when water is present in sufficient amount (more than four water molecules per ion pair), stability of the cations is expected to significantly improve. However, lower amounts of water result in the formation of isolated molecular clusters and ammonium hydroxide pairing that lead to degradation of the cation. The composition and size of the water–hydroxide–cation c...

Enhanced Selectivity of the Separation of CO2from N2during Crystallization of Semi-Clathrates from Quaternary Ammonium Solutions

CO2 mitigation is crucial environmental problem and a societal challenge for this century. CO2 capture and sequestration is a route to solve a part of the problem, especially for the industries in which the gases to be treated are well localized. CO2 capture by using hydrate is a process in which the cost of the separation is due to compression of gases to reach the gas hydrate formation conditions. Under pressure, the water and gas forms a solid that encapsulates preferentially CO2 . The gas hydrate formation requires high pressures and low temperatures, which explains the use of thermodynamic promoters to decrease the operative pressure. Quaternary ammoniums salts represent an interesting family of components because of their thermodynamic effect, but also because they can generate crystals that are easily handled. In this work, we have made experiments concerning the equilibrium of (CO2 , N2 ) in presence of Tetra-n-Butyl Ammonium Bromide (TBAB) which form a semi-clathrate hydrate. We propose equilibrium data (pressure, temperature) in presence of TBAB at different concentrations and we compare them to the literature. We have also measured the composition of the hydrate phase in equilibrium with the gas phase at different CO2 concentrations. We observe that the selectivity of the separation is dramatically increased in comparison to the selectivity of the pure water gas clathrate hydrate. We observe also a benefice on the operative pressure which can be dropped down to the atmospheric pressure.

Use of quaternary ammonium to control the spread of aquatic invasive species by wildland fire equipment

Wildland firefighting equipment moves large volumes of raw water during fire incidents in order to extinguish flames or control fire growth. This water movement may serve as pathways for aquatic invasive organisms to be moved between water bodies and watersheds. The equipment used may become contaminated and serve as vectors for future invasions across large geographic areas. New guidelines used by federal firefighting agencies recommend the application of sanitation solutions using quaternary ammonium compounds for decontaminating wildland fire equipment to prevent the spread of aquatic invasive species that may foul the equipment. While quaternary ammonium compounds have been tested on other aquatic organisms, the effectiveness of such compounds has not been systematically tested on dreissenid mussels. We tested the survival of quagga mussel veligers after exposure to a 3% solution of Sparquat 256 ® for 5 and 10 minutes. We assessed survival immediately after treatment and then after 60 minutes in fresh water. We found that a 5 minute exposure duration was insufficient to kill 100% of tested veligers. However a 10 minute exposure, as prescribed in the interagency operational guidelines for preventing spread of aquatic invasive species, was effective in killing all tested veligers, but not immediately after treatment. An additional 60 minutes were required after the quaternary ammonium solution was removed before 100% mortality was achieved. This work highlights the need for more rigorous evaluation of the effectiveness of various sanitation solutions in killing quagga and zebra mussels under different ambient temperatures in order to validate and refine the sanitation protocol for firefighting equipment and other applications.

A Comparison of Disinfectants to Prevent Spread of Potyviruses in Greenhouse Tomato Production

Potyviruses, transmitted by a diverse array of common aphid species, infect a broad range of vegetable crops, and can be problematic in greenhouse tomato production. Once introduced, these viruses are believed to be transmitted plant-to-plant during pruning operations, and can infect large sections of a greenhouse, resulting in significant losses in fruit quality and yield. Several methods are used for virus management in greenhouse production, including rouging of diseased plants and treatment of tools and facilities with virucides to eradicate the virus responsible. To clarify potyvirus transmission efficiency from an infected source during pruning operations, experiments were conducted using direct and serial mechanical inoculation of Potato virus Y (PVY) using a scalpel dipped in a suspension of PVY-infected plant sap. Tests demonstrated that both serial and direct inoculation resulted in significant PVY transmission, but that transmission rates declined after the first few plants in serial transmission. Additional tests evaluated the efficiency of two virucides, a quaternary ammonium solution and sodium hypochlorite, for virus inactivation during pruning operations using a range of concentrations and time points. Results demonstrated that 0.5% sodium hypochlorite treatment for two seconds was sufficient for virus control, and superior to treatment with quaternary ammonium solutions. Accepted for publication 20 December 2010. Published 21 February 2011.

Mycobacterium chelonaeWound Infection after Liposuction

To the Editor: We recently investigated a case of Mycobacterium chelonae abdominal wound infection after liposuction performed under local anesthesia at an outpatient medical office. Our aim was to determine whether other cases of atypical mycobaterial infections had previously occurred after liposuction. M. chelonae is widely distributed in soil and water, including tap water. Atypical mycobacterial infections have been associated with skin and soft tissue infections, including infections after cosmetic surgeries, and outbreaks have been documented (1–4). Previously reported potential sources of liposuction equipment contamination have been inadequate disinfection or sterilization after rinsing of liposuction equipment with tap water, tap water used in cleaning liposuction cannulae, or the quaternary ammonium solution used to disinfect liposuction equipment (2,4). Increased numbers of procedures performed in freestanding medical centers (not connected with hospitals) that are not routinely monitored by infection control committees or equivalent oversight bodies may contribute to atypical mycobacterial infection (1). Our investigation showed that proper cleaning, disinfection, and sterilization of liposuction equipment and other infection control issues at this medical office were concerns. Except for the physician, only unlicensed medical assistants worked at this office. This staff had been trained to clean and sterilize liposuction equipment, but no written procedures existed for processing reusable liposuction equipment, no logs were kept of autoclave use for sterilization, and preventive maintenance checks and verification of sterility on the autoclave by using biological indicators as recommended by the manufacturer were not performed. The office did not have any general written infection control policies. Office staff mixed leftover solutions from open small bottles of povidone iodine and placed this mixture into larger containers. Staff stored wet alcohol-soaked cotton balls in multiuse containers for wiping tops of multidose vials instead of using individual alcohol prep pads; and 70% isopropyl alcohol solution from an open nonsterile bottle was used instead of sterile irrigation solutions to flush the liposuction suction cannula to dislodge tissue from the ports during the procedure. Case finding and surveillance of acid-fast bacilli results routinely reported to our public health tuberculosis program did not indicate any other cases of postliposuction wound infections caused by atypical mycobacteria associated with this office. Laboratory testing of environmental samples, including tap water and faucet aerator samples, also did not indicate a source for M. chelonae in this outpatient office. This case was likely an isolated occurrence in which the case-patient acquired infection through an environmental source unrelated to this office. However, because of the infection control concerns observed in this office and because the incubation period for M. chelonae can be as long as 5 months (2), the physician was advised to develop infection control policies and procedures; develop protocols for cleaning, disinfecting, and sterilizing liposuction equipment in accordance with the manufacturer’s recommendations; ensure autoclave sterility by using biological indicators; educate office staff about basic infection control practices and use of aseptic techniques; and notify public health officials of any further infections postliposuction. Risk factors that cause or contribute to infectious disease outbreaks in outpatient settings include inadequate cleaning, disinfection, sterilization, and storage of instruments and equipment; inappropriate use of barrier equipment, such as gloves, by healthcare personnel; inadequate handwashing practices by healthcare workers; failure to use aseptic techniques; and lack of familiarity with established infection control practices by ambulatory care personnel (5). Also, in the outpatient setting, responsibility for implementing an infection control program usually is not assigned to a specific person (5), and outpatient medical offices are not routinely monitored by oversight bodies or infection control committees as are hospitals and outpatient surgical centers (6). The California Business and Professions Code requires that outpatient surgery settings using anesthesia, other than local anesthesia or peripheral nerve blocks, be accredited by an oversight body. However, because this facility used only local anesthesia, it did not fall under this code of regulations for facility accreditation, oversight, certification standards, and quality assurance for general public health safety and welfare. Lack of adherence to basic infection control principles, specifically in outpatient settings, has resulted in outbreaks (1,7–10). Our findings at this medical office further highlight the unaddressed infection control problems in outpatient settings. Because of insufficient oversight for the outpatient setting, professional organizations, state medical boards, and federal and state authorities should consider the need to systematically address infection control standards and monitoring tailored for this setting. As more healthcare procedures move to the outpatient setting, ensuring appropriate infection control practices can prevent outbreaks.

Influence of Fluorine on the Catalytic Performance of Ti−Beta Zeolite

Treatment of Ti−Beta synthesized by the fluoride method with basic quaternary ammonium solution followed by calcination enhanced the epoxidation activity with hydrogen peroxide, which is due to the reduction of the amount of fluorine contained in the catalyst.

Rapid Determination of Sanitizer Concentration Using Impedance-Based Methods

Chlorine, iodophor, and quaternary ammonium solutions of various concentrations were assayed with rapid test kits and with three Bactometer impedimetric test codes (the impedance, conductance, and capacitance test codes). An initial study was conducted to determine which test code was most suitable for each sanitizer. Impedance was shown to be the best for sodium hypochlorite solutions, conductance for iodophor solutions, and capacitance for quaternary ammonium solutions. When Bactometer results were compared with test kit results, linear regression revealed strong correlations for all three sanitizer solutions. For sodium hypochlorite concentrations of 0 to 100 ppm and 100 to 1,000 ppm, R2 values of 0.87 and 0.99, respectively, were obtained. For iodophor concentrations between 25 to 150 ppm, an R2 value of 0.95 was obtained. For quaternary ammonium compound concentrations of 100 to 1,000 ppm, an R2 value of 0.94 was obtained. The impedimetric methods proved to be simple and rapid (6 min) alternatives for measuring concentrations of the sanitizer solutions with a high level of certainty (P < 0.0002). The Bactometer will save time when multiple samples are tested.

Combined monte carlo/thermodynamic model of formation of microporous aggregate structure like silica from quaternary ammonium silicate solutions

AbstractQuaternary ammonium silicate is a surfactant with very high content of silica that allows its use for preparation of protective coatings. The problem of silica aggregation from quaternary ammonium solution in limited volume is the focus of this paper. The system is described by a model based on a Monte Carbo approach with thermodynamic limitations. Thermodynamic characteristics are estimated by statistical polymer method. The model is employed for estimation of such properties as monomer concentration and tortuosity. The results of computer simulation are used for forecasting properties of coatings and for practical preparation of samples coated with quaternary ammonium silicate‐based composition.

Environmental Control to Reduce Transmission ofClostridium difficile

Restrictive antibiotic policies and infection control measures have been shown to reduce the incidence of Clostridium difficile-associated diarrhea (CDAD) among hospitalized patients. To date, the role of environmental disinfectants in reducing nosocomial CDAD rates has not been well studied. In a before-and-after intervention study, patients in 3 units were evaluated to determine if unbuffered 1:10 hypochlorite solution is effective as an environmental disinfectant in reducing the incidence of CDAD. Among 4252 patients, the incidence rate of CDAD for bone marrow transplant patients decreased significantly, from 8.6 to 3.3 cases per 1000 patient-days (hazard ratio, 0.37; 95% confidence interval, 0.19-0.74), after the environmental disinfectant was switched from quaternary ammonium to 1:10 hypochlorite solution in the rooms of patients with CDAD. Reverting later to quaternary ammonium solution increased the CDAD rate to 8.1 cases per 1000 patient-days. No reduction in CDAD rates was seen among neurosurgical intensive care unit and general medicine patients, for whom baseline rates were 3.0 and 1.3 cases per 1000 patient-days, respectively. Unbuffered 1:10 hypochlorite solution is effective in decreasing patients' risk of developing CDAD in areas where CDAD is highly endemic. Presumed mechanisms include reducing the environmental burden and the potential for C. difficile transmission among susceptible patients.

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.

WASHING AND SANITIZING THE COW'S UDDER

Liberal use of a plain water wash, preceding a bactericidal treatment is an effective means of sanitizing the cow's udder, preparatory to milking. Both hypochlorite and quaternary ammonium bactericides are aided by the plain water rinse. In this study hypochlorite reduced bacteria counts on teat surfaces and in the milk more satisfactorily than quaternary ammonium solution.