1. Antimicrobial resistance due to the use of biocides and heavy metals: a literature review Scientific Opinion on the Panel Panel on Microbial Ecology of the Norwegian Scientific Committee for Food Safety
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Norwegian Scientific Committee For Food Safety (VKM)
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literature study ,antibiotic resistance ,norwegian scientific committee for food safety ,assessment ,vkm ,biocides ,antibiotics ,norwegian environment agency ,norway ,antimicrobial resistance ,heavy metals - Abstract
Antimicrobial resistance (AMR) in bacteria (often referred to as antibiotic resistance) is one of the major public health challenges of our time. AMR can be described as the ability of a bacterium to withstand the effects of an antimicrobial agent. In addition to antimicrobial agents used for treatment and prophylaxis in humans, animals, and plants, chemical susbtances, such as biocides and heavy metals, may also induce resistance in bacteria against antimicrobial agents used in human and veterinary medicine. In June 2016, the Norwegian Environment Agency requested the Norwegian Scientific Committee for Food Safety (VKM) to conduct a literature review regarding development of bacterial resistance to biocides and heavy metals and cross-resistance to antimicrobial agents (e.g., antibiotics) in bacteria, with the following mandate: 1. List chemical substances that may contribute to increased antimicrobial resistance. 2. Describe the substances listed in question 1 that are used/in use in Norway and assess which fields of applications that have the potential to contribute to increased resistance. 3. Range the substances according to field of application that is assumed to have the strongest effect on development of resistance, based on characteristics and amount used. 4. Identify knowledge gaps according to the effect of these substances on development of resistance. In order to answer the mandate, VKM appointed a working group consisting of two members of the Panel on Microbial Ecology, and one external expert, to prepare a draft opinion document and answer the questions. The Panel on Microbial Ecology has reviewed and revised the draft prepared by the working group and approved the opinion document “Antimicrobial resistance due to the use of biocides and heavy metals: a literature review”. A biocide is defined as an active chemical molecule that controls the growth of, or kills, bacteria and other microorganisms in a biocidal product. The biocides are classified into 4 main groups according to their application categories and further sub-divided into 23 product groups. In this assessment, we focus on biocides with potential antibacterial activity and their ability to induce antimicrobial (antibiotic) resistance in bacteria. These products belong mostly to main group 1; Disinfectants. Disinfectants include products used in human hygiene, veterinary hygiene, water treatment, and products used in the field of food and feed, but excludes cleaning products that are not intended to have a biocidal effect, including washing liquids, powders, and similar products. Heavy metals are naturally occurring elements that have a high atomic weight and a density that is at least 5 times greater than that of water. Some heavy metals have been used as antimicrobial agents since antiquity, but often their modes of action have remained unclear. They are able to induce toxicity at low levels of exposure. In this report we have chosen to include the following elements in the category “heavy metals”: silver (Ag), arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), and zinc (Zn). The selection is based on their area of use and on their ability to induce AMR. Although most biocides and heavy metals are known to be high volume products, the working group was not able to obtain detailed data on the amounts used in Norway. However, there is no doubt that the production and usage volumes and the area of application for several of these substances are several orders of magnitude higher than those of antimicrobial agents used in therapy and prophylaxis. This Opinion document is not a traditional risk assessment, but a literature study that presents and compiles the available information regarding resistance development in bacteria due to use/misuse of biocides and heavy metals. Exposure assessment and risk characterization have therefore been excluded. The following definitions regarding probability of biocides and heavy metals inducing AMR in bacteria are used: Highly likely - is expected to occur in most circumstances Likely - could occur in many circumstances Unlikely - could occur in some circumstances Highly unlikely (effectively zero) - may occur only in very rare circumstances The most commonly used chemical substances with the potential to induce AMR and cross or co-resistance in bacteria are the heavy metals, copper, zinc, and cadmium (“highly likely”). Phenols, especially triclosan, surface-active agents, especially quaternary ammonium compounds (QACs), and the heavy metals arsenic and mercury are classified in the category “likely”. The components in the “unlikely” group are aldehydes, biguanides, organic acids, inorganic acids, antimicrobial dyes, diaminides, and silver. It should be noted that a number of uncertainties are associated with assigning these substances to particular categories of probabilities/likelihoods (highly likely, likely, unlikely, and highly unlikely) in this assessment. Bacteria are living organisms that are continually changing their genetic compositions, and are able to adapt rapidly to altered living conditions. Furthermore, the concentrations of the substances to which the bacteria are exposed affects the probability of inducing resistance. This report reviews the literature describing the current situation with regards to development of resistance in bacteria due to biocides and heavy metals. The current situation and genetic and phenotypic status may change as bacteria continue to adapt to exposure to biocides/heavy metals and antimicrobial agents at varying doses, durations, and combinations. Data gaps There is a lack of knowledge regarding the diverse reservoir of AMR in the environment including soil, sediment, water, air, wild plants, and animals that are impacted by biocides and heavy metals. We have not been able to gather sufficient data on the amount of the different biocides and heavy metals that end up, unintentionally, in the environment in Norway and the extent to which such exposure, alone or in combination with other antimicrobials, may result in development of AMR in microbial communities. Furthermore, limited data are available regarding use/misuse/presence of biocides and heavy metals in consumer products. Knowledge regarding development of resistance in bacteria due to use of biocides or heavy metals in cosmetic products is lacking., NO; PDF; vkm@vkm.no
- Published
- 2020
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