Acute Toxicity Testing by the Dermal Route
Rhoda G. M. Wang, James B. Knaak, Howard I. Maibach in Health Risk Assessment, 2017
The EPA’s regulations apply to two classes of chemicals — general industrial chemicals and biocides (pesticides). The former are regulated by the Toxic Substances Control Act (TSCA), while the latter fall under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). Most nonpesticide chemicals manufactured, processed, distributed, or used in the United States that may become an environmental problem or a health risk, and that are not specifically regulated by other agencies, must be tested as specified by the TSCA.63 Any agent intended for poisoning or control of insects, animal pests, plants, bacteria, or fungi must be tested under FIFRA guidelines. Toxicity testing must comply with EPA Good Laboratory Practices (GLP).64,65 Under the GLP, the EPA has the authority to conduct inspections of the testing facility and verify the validity of study data.
Legionella Pneumophila Infection
Meera Chand, John Holton in Case Studies in Infection Control, 2018
Nosocomial cases should prompt a retrospective review of nosocomial pneumonia over 3–6 months plus prospective laboratory testing. Plumbing controls involve elimination of dead legs, correct temperature control in both hot and cold water systems by keeping hot water above 50°C and cold water below 20°C, and reducing stagnation in the water systems. To avoid scalding in hospitals, thermostatic mixing valves have to be installed. Environmental control depends on adherence to national guidance for risk assessment and maintenance. Monitoring of biocide and thermal control is essential. Culture of potable water is performed in hospitals where patients may be immunocompromised. Remedial action is required if positive cultures are obtained.
Evaluation of Specific Classes of Chemical
David Woolley, Adam Woolley in Practical Toxicology, 2017
A biocide can be a single chemical, a mixture of more or less known composition, microorganisms, extracts, and oils of plants. Each of these categories has its own challenges in terms of safety evaluation; single substances are relatively straightforward, but mixtures are notoriously difficult to assess, the complexity increasing with the number of ingredients or components. In some cases, the active agent is produced by mixing two or more components at the point of use and so may differ from the original components; in these cases, the toxicological assessment has to cover the original unmixed chemicals and the (probably) more biologically active final product.
Fatty acids, esters, and biogenic oil disinfectants: novel agents against bacteria
Published in Baylor University Medical Center Proceedings, 2023
Aruna Lamba, Jonathan Kopel, David Westenberg, Shubhender Kapila
The chemical disinfectants (or biocides) are broadly classified as phenolic compounds, alcohols, quaternary ammonium compounds, chlorine compounds, aldehydes, halogenated tertiary amines, hydrogen peroxide, and gases like ethylene oxide with different modes of action that remain largely unknown. These biocides are effective against a wide range of bacteria, both gram positive and gram negative. The most important characteristics of the ideal disinfectant are broad-spectrum antimicrobial activity, solubility, stability, safety for humans and other animals, homogeneity, noncombination with extraneous organic material, toxicity to microorganisms at room or body temperature, capacity to penetrate, deodorizing ability, inexpensive, noncorrosive, and availability. However, no one disinfectant meets all these characteristics. The efficacy of disinfection is affected by a number of factors, each of which may nullify or limit the process. Some of the factors that have been shown to affect disinfection efficacy are the previous state of the object, the organic load on the object, the type and level of microbial contamination, the concentration and exposure time to the germicide, the physical configuration of the object, and the temperature and pH of the disinfection process.
From laboratory tests to field trials: a review of cathodic protection and microbially influenced corrosion
Published in Biofouling, 2022
A. A. Thompson, J. L. Wood, E. A. Palombo, W. K. Green, S. A. Wade
With respect to the prevention of MIC, a range of options including physical, chemical, biological, and electrochemical methods have been proposed (Javaherdashti 2017a). Physical methods often involve direct cleaning of surfaces and the application of coatings such as paint, plastic or rubber to shield the metal from the outside environment (Montemor 2014). Chemical methods include the use of various biocides to kill the microbes within biofilms that form on metallic surfaces, with common examples being chlorine, hydrogen peroxide and ozone (Videla 2002). Biological methods are designed to replace or modify existing biofilms with microbes that are non-corrosive (Zuo 2007). Finally, electrochemical methods aim to alter the corrosion reactions between the metal and the environment by slowing reactions and preserving structural integrity (Javaherdashti 2017b). An electrochemical method that is widely used in a variety of industries for the prevention of corrosion is cathodic protection (CP) (Büchler et al. 2017).
Tolerance to disinfectants (chlorhexidine and isopropanol) and its association with antibiotic resistance in clinically-related Klebsiella pneumoniae isolates
Published in Pathogens and Global Health, 2021
Jasmine Morante, Antonio M. Quispe, Barbara Ymaña, Jeel Moya-Salazar, Néstor Luque, Gabriela Soza, María Ramos Chirinos, Maria J Pons
Biocides are routinely used in healthcare settings and play an essential role in infection control [1], one that has been highlighted during the fight against SARS-CoV-2. Two of the most frequently used types of biocides in hospitals are chlorhexidine digluconate (CHG) and isopropyl alcohol (ISP). Chlorhexidine is a bisbiguanide antiseptic used against a wide range of microorganisms. It functions by forming a bridge between phospholipids with subsequent displacement of cations (Mg2+ and Ca2+) [2], resulting in membrane disruption via a reduction in the capacity of the bacterial membrane to osmoregulate and changes in enzymes associated with metabolic membrane capability [2]. Chlorhexidine is often used for procedures such as handwashing, preoperative preparation, and surface disinfection because of its bacteriostatic and bactericidal properties [3,4], as well as its ability to rapidly denature the proteins of microorganisms [5].
Related Knowledge Centers
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