https://discovery.dundee.ac.uk/ws/files/20668273/Manuscript_ARGs_in_Global_Lakes_2018_04_06_Elsevier_No_Track.pdf

Antibiotics and antibiotic resistance genes in global lakes: A review and meta-analysis.

As the human population increases there is an increasing reliance on aquaculture to supply a safe, reliable, and economic supply of food Although food production is essential for a healthy population, an increasing threat to global human health is antimicrobial resistance Extensive antibiotic resistant strains are now being detected; the spread of these strains could greatly reduce medical treatment options available and increase deaths from previously curable infections Antibiotic resistance is widespread due in part to clinical overuse and misuse; however, the natural processes of horizontal gene transfer and mutation events that allow genetic exchange within microbial populations have been ongoing since ancient times By their nature, aquaculture systems contain high numbers of diverse bacteria, which exist in combination with the current and past use of antibiotics, probiotics, prebiotics, and other treatment regimens—singularly or in combination These systems have been designated as “genetic hotspots” for gene transfer As our reliance on aquaculture grows, it is essential that we identify the sources and sinks of antimicrobial resistance, and monitor and analyse the transfer of antimicrobial resistance between the microbial community, the environment, and the farmed product, in order to better understand the implications to human and environmental health

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The Rising Tide of Antimicrobial Resistance in Aquaculture: Sources, Sinks and Solutions.

Pharmaceuticals and personal care products (PPCP) are compounds with special physical and chemical properties that address the care of animal and human health. PPCP have been detected in surface water and wastewater in the ng/L to µg/L concentration range worldwide. PPCP ecotoxicity has been studied in a variety of organisms, and multiple methods have been used to assess the risk of PPCP in the environment to ecological health. Here we review the occurrence, effects, and risk assessment of PPCP in aquatic systems, as well as the sustainability of current methods for managing PPCP contamination in aquatic systems. The major points are the following: (1) a number of PPCP present potential concerns at environmentally relevant concentrations. PPCP mixtures may produce synergistic toxicity. (2) Various methods have been used for the ecological risk assessment of PPCP in aquatic systems. There are similarities in these methods, but no consensus has emerged regarding best practices for the ecological risk assessment of these compounds. (3) Human health risk assessments of PPCP contamination in aquatic systems have generally indicated little cause for concern. However, there is a lack of information regarding whether antibiotic contamination in wastewater and aquatic systems could lead to an increase in clinically relevant antibiotic-resistant bacteria and antibiotic-resistant genes. (4) Over the next century, the combination of increasing global population size and potential droughts may result in reduced water availability, increased need for water reuse, and increasing concentrations of PPCP in wastewaters. The current wastewater treatment methods do not remove all PPCP effectively. This, coupled with the possibility that antibiotics may promote the development of antibiotic-resistant bacteria and antibiotic-resistant genes, leads to concerns about the sustainability of global water supplies.

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Pharmaceuticals and personal care products in waters: occurrence, toxicity, and risk.

The main goal of this manuscript is to review different treatment strategies and mechanisms for combating the antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs) in the wastewater environment. The high amount of antibiotics is released into the wastewater that may promote selection of ARB and ARGs which find their way into natural environments. Emerging microbial pathogens and increasing antibiotic resistance among them is a global public health issue. The propagation and spread of ARB and ARGs in the environment may result in an increase of antibiotic resistant microbial pathogens which is a worldwide environmental and public health concern. A proper treatment of wastewater is essential before its discharge into rivers, lake, or sewage system to prevent the spread of ARB and ARGs into the environment. This review discusses various treatment options applied for combating the spread of ARB and ARGs in wastewater treatment plants (WWTPs). It was reported that low-energy anaerobic-aerobic treatment reactors, constructed wetlands, and disinfection processes have shown good removal efficiencies. Nanomaterials and biochar combined with other treatment methods and coagulation process are very recent strategies regarding ARB and ARGs removal and need more investigation and research. Based on current studies a wide-ranging removal efficiency of ARGs can be achieved depending on the type of genes present and treatment processes used, still, there are gaps that need to be further investigated. In order to find solutions to control dissemination of antibiotic resistance in the environment, it is important to (1) study innovative strategies in large scale and over a long time to reach an actual evaluation, (2) develop risk assessment studies to precisely understand occurrence and abundance of ARB/ARGs so that their potential risks to human health can be determined, and (3) consider operating and environmental factors that affect the efficiency of each treatment mechanism.

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Strategies to Combat Antibiotic Resistance in the Wastewater Treatment Plants.

The lack of new antibiotic classes calls for a cautious use of existing agents. Yet, every 10 min, almost two tons of antibiotics are used around the world, all too often without any prescription or control. The use, overuse and misuse of antibiotics select for resistance in numerous species of bacteria which then renders antimicrobial treatment ineffective. Almost all countries face increased antimicrobial resistance (AMR), not only in humans but also in livestock and along the food chain. The spread of AMR is fueled by growing human and animal populations, uncontrolled contamination of fresh water supplies, and increases in international travel, migration and trade. In this context of global concern, 68 international experts attending the fifth edition of the World HAI Resistance Forum in June 2015 shared their successes and failures in the global fight against AMR. They underlined the need for a “One Health” approach requiring research, surveillance, and interventions across human, veterinary, agricultural and environmental sectors. This strategy involves concerted actions on several fronts. Improved education and increased public awareness are a well-understood priority. Surveillance systems monitoring infections need to be expanded to include antimicrobial use, as well as the emergence and spread of AMR within clinical and environmental samples. Adherence to practices to prevent and control the spread of infections is mandatory to reduce the requirement of antimicrobials in general care and agriculture. Antibiotics need to be banned as growth promoters for farm animals in countries where it has not yet been done. Antimicrobial stewardship programmes in animal husbandry have proved to be efficient for minimising AMR, without compromising productivity. Regarding the use of antibiotics in humans, new tools to provide highly specific diagnoses of pathogens can decrease diagnostic uncertainty and improve clinical management. Finally, infection prevention and control measures – some of them as simple as hand hygiene – are essential and should be extended beyond healthcare settings. Aside from regulatory actions, all people can assist in AMR reduction by limiting antibiotic use for minor illnesses. Together, we can all work to reduce the burden of AMR.

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Antimicrobial resistance: one world, one fight!

Wastewater treatment plants (WWTP) receive the effluents from various sources (communities, industrial, and hospital effluents) and are recognized as reservoir for antibiotic-resistance genes (ARGs) that are associated with clinical pathogens. The aquatic environment is considered a hot-spot for horizontal gene transfer, and lake sediments offer the opportunity for reconstructing the pollution history and evaluating the impacts. In this context, variation with depth and time of the total bacterial load, the abundance of faecal indicator bacteria (FIB; E. coli and Enterococcus spp. (ENT)), Pseudomonas spp., and ARGs (blaTEM, blaSHV, blaCTX-M, blaNDM, and aadA) were quantified in sediment profiles of different parts of Lake Geneva using quantitative PCR. The abundance of bacterial marker genes was identified in sediments contaminated by WWTP following eutrophication of the lake. Additionally, ARGs, including the extended-spectrum s-lactam- and aminoglycoside-resistance genes, were identified in the surface sediments. The ARG and FIB abundance strongly correlated (r ≥ 0.403, p < 0.05, n = 34) with organic matter and metal concentrations in the sediments, indicating a common and contemporary source of contamination. The contamination of sediments by untreated or partially treated effluent water can affect the quality of ecosystem. Therefore, the reduction of contaminants from the source is recommended for further improvement of water quality.

Maria Meijer

Papers

Accumulation of clinically relevant antibiotic-resistance genes, bacterial load, and metals in freshwater lake sediments in Central Europe.