Pollution from drug manufacturing: review and perspectives

A review on reactive oxygen species-induced mechanism pathways of pharmaceutical waste degradation: Acetaminophen as a drug waste model

Innately designed to induce physiological changes, pharmaceuticals are foreknowingly hazardous to the ecosystem. Advanced oxidation processes (AOPs) are recognized as a set of contemporary and highly efficient methods being used as a contrivance for the removal of pharmaceutical residues. Since reactive oxygen species (ROS) are formed in these processes to interact and contribute directly toward the oxidation of target contaminant(s), a profound insight regarding the mechanisms of ROS leading to the degradation of pharmaceuticals is fundamentally significant. The conceptualization of some specific reaction mechanisms allows the design of an effective and safe degradation process that can empirically reduce the environmental impact of the micropollutants. This review mainly deliberates the mechanistic reaction pathways for ROS-mediated degradation of pharmaceuticals often leading to complete mineralization, with a focus on acetaminophen as a drug waste model.

Pharmaceutical Pollutants: Ecotoxicological Impacts and the Use of Agro-Industrial Waste for Their Removal from Aquatic Environments

Medicines are pharmaceutical substances used to treat, prevent, or relieve symptoms of different diseases in animals and humans. However, their large-scale production and use worldwide cause their release to the environment. Pharmaceutical molecules are currently considered emerging pollutants that enter water bodies due to inadequate management, affecting water quality and generating adverse effects on aquatic organisms. Hence, different alternatives for pharmaceuticals removal from water have been sought; among them, the use of agro-industrial wastes has been proposed, mainly because of its high availability and low cost. This review highlights the adverse ecotoxicological effects related to the presence of different pharmaceuticals on aquatic environments and analyzes 94 investigations, from 2012 to 2024, on the removal of 17 antibiotics, highlighting sulfamethoxazole as the most reported, as well as 6 non-steroidal anti-inflammatory drugs (NSAIDs) such as diclofenac and ibuprofen, and 27 pharmaceutical drugs with different pharmacological activities. The removal of these drugs was evaluated using agro-industrial wastes such as wheat straw, mung bean husk, bagasse, bamboo, olive stones, rice straw, pinewood, rice husk, among others. On average, 60% of the agro-industrial wastes were transformed into biochar to be used as a biosorbents for pharmaceuticals removal. The diversity in experimental conditions among the removal studies makes it difficult to stablish which agro-industrial waste has the greatest removal capacity; therefore, in this review, the drug mass removal rate (DMRR) was calculated, a parameter used with comparative purposes. Almond shell-activated biochar showed the highest removal rate for antibiotics (1940 mg/g·h), while cork powder (CP) (10,420 mg/g·h) showed the highest for NSAIDs. Therefore, scientific evidence demonstrates that agro-industrial waste is a promising alternative for the removal of emerging pollutants such as pharmaceuticals substances.

Computational Screening of Hydrophobic Zeolites for the Removal of Emerging Organic Contaminants from Water

The pollution of water resources by pharmaceuticals and agents of personal care products (PPCPs) poses an increasingly pressing issue that has received considerable attention from scientists and government agencies alike. Hydrophobic zeolites can serve as selective adsorbents to remove these contaminants from aqueous solution. So far, the adsorption of PPCPs in zeolites has often been investigated in case studies focusing on a small number of contaminants and one or a few zeolites. We present a computational screening approach to investigate the interaction of 53 PPCPs with 14 all-silica zeolites, aiming at a more comprehensive understanding of factors that are beneficial for a strong host-guest interaction and thus an efficient adsorption. The systems are modelled on the classical force field level of theory, allowing for the efficient computational treatment of a large number of PPCP-zeolite combinations and evaluated in terms of the interaction energy between PPCP and zeolite framework. For selected PPCP-zeolite combinations additional Free Energy Perturbation simulations are employed to compute Free Energies of Transfer between the aqueous phase and the adsorbed state. These results can serve as a starting point for experimental studies of relevant PPCP-zeolite combination or more in-depth theoretical investigations.

Spatiotemporal variations and priority ranking of emerging contaminants in nanwan reservoir: A case study from the agricultural region in huaihe river basin in China

The presence of emerging contaminants (ECs) in drinking water sources is an increasing concern, yet limited data exists on their occurrence and risk in the upper Huaihe River Basin, an important agricultural region in Central China. This study investigated 70 ECs, including pesticide and antibiotics in surface water from drinking water source areas in Nanwan Reservoir along the upper reaches of the Huaihe River Basin to prioritize the ECs based on ecological risk and health risk assessment. A total of 66 ECs were detected in the surface water at least once at the selected 38 sampling sites, with concentrations ranging from 0.04 to 2508 ng/L. Ecological risk assessment using the risk quotient (RQ) method revealed high risks (RQ > 1) from 7 ECs in the dry season and 15 ECs in the wet season, with triazine pesticides as the main contributors. Non-carcinogenic risks were below negligible levels, but carcinogenic risks from neonicotinoid and carbamate pesticides and macrolide antibiotics were concerning for teenagers. Ciprofloxacin exhibited a high level of resistance risk during the wet season. A multi-indicator prioritization approach integrating occurrence, risk, and chemical property data ranked 6 pesticides and 3 antibiotics as priority pollutants. The results highlight EC contamination of drinking water sources in this agriculturally-intensive region and the need for targeted monitoring and management to protect water quality.

Degradation pathways of sulfamethoxazole under phototransformation processes: A data base of the major transformation products for their environmental monitoring

Sulfamethoxazole (SMX) is frequently detected in wastewater and aquatic environments worldwide at concentrations from ng L-1 to μg L-1. Unfortunately, SMX is not completely removed in municipal wastewater treatment plants (WWTPs), thus, SMX and their transformation products (TPs) are discharged into aquatic environments, where can be transformed by phototransformation reactions. In this study, the phototransformation of SMX as well as generation of their major TPs under photolysis and photocatalysis processes was reviewed. SMX can be totally removed under photolysis and photocatalysis processes in aqueous solutions using simulated or natural radiation. Degradation pathways such as isomerization, hydroxylation, fragmentation, nitration, and substitution reactions were identified during the generation of the major TPs of SMX. Particularly, 26 TPs were considered for the creation of a data base of the major TPs of SMX generated under phototransformation processes. These 26 compounds could be used as reference during the SMX monitoring both wastewater and water bodies, using analytic methodologies such as target analysis and suspect screening. A data base of the major TPs of pharmaceuticals active compounds (PhACs) as SMX could help to implementation of best environmental monitoring programs for the study of the environmental risks both PhACs and their TPs with highest occurrence in aquatic environments.

Impact of veterinary pharmaceuticals on environment and their mitigation through microbial bioremediation

Veterinary medications are constantly being used for the diagnosis, treatment, and prevention of diseases in livestock. However, untreated veterinary drug active compounds are interminably discharged into numerous water bodies and terrestrial ecosystems, during production procedures, improper disposal of empty containers, unused medication or animal feed, and treatment procedures. This exhaustive review describes the different pathways through which veterinary medications enter the environment, discussing the role of agricultural practices and improper disposal methods. The detrimental effects of veterinary drug compounds on aquatic and terrestrial ecosystems are elaborated with examples of specific veterinary drugs and their known impacts. This review also aims to detail the mechanisms by which microbes degrade veterinary drug compounds as well as highlighting successful case studies and recent advancements in microbe-based bioremediation. It also elaborates on microbial electrochemical technologies as an eco-friendly solution for removing pharmaceutical pollutants from wastewater. Lastly, we have summarized potential innovations and challenges in implementing bioremediation on a large scale under the section prospects and advancements in this field.

Recent Advances in Thiourea Based Colorimetric and Fluorescent Chemosensors for Detection of Anions and Neutral Analytes: A Review

Thioureas and their derivatives are organosulfur compounds having excellent biological and non-biological applications. These compounds contain S- and N-, which are nucleophilic and allow for establishing inter-and intramolecular hydrogen bonding. These characteristics make thiourea moiety a very important chemosensor to detect various environmental pollutants. This article covers a broad range of thioureas and their derivatives that are used for highly sensitive, selective, and simple fluorimetric (turn-off and turn-on), and colorimetric chemosensors for the detection and determination of different types of anions, such as CN-, AcO-, F-, ClO- and citrate ions, etc., and neutral analytes such as ATP, DCP, and Amlodipine, etc., in biological, environmental, and agriculture samples. Further, the sensing performances of thioureas-based chemosensors have been compared and discussed, which could help the readers for the future design of organic fluorescent and colorimetric sensors to detect anions and neutral analytes. We hope this study will support the new thoughts to design highly efficient, selective, and sensitive chemosensors to detect different analytes in biological, environmental, and agricultural samples.

Non-Canonical Aspects of Antibiotics and Antibiotic Resistance

The understanding of antibiotic resistance, one of the major health threats of our time, is mostly based on dated and incomplete notions, especially in clinical contexts. The "canonical" mechanisms of action and pharmacodynamics of antibiotics, as well as the methods used to assess their activity upon bacteria, have not changed in decades; the same applies to the definition, acquisition, selective pressures, and drivers of resistance. As a consequence, the strategies to improve antibiotic usage and overcome resistance have ultimately failed. This review gathers most of the "non-canonical" notions on antibiotics and resistance: from the alternative mechanisms of action of antibiotics and the limitations of susceptibility testing to the wide variety of selective pressures, lateral gene transfer mechanisms, ubiquity, and societal factors maintaining resistance. Only by having a "big picture" view of the problem can adequate strategies to harness resistance be devised. These strategies must be global, addressing the many aspects that drive the increasing prevalence of resistant bacteria aside from the clinical use of antibiotics.

Dissemination, virulence characteristic, antibiotic resistance determinants of emerging linezolid and vancomycin-resistant Enterococcus spp. in fish and crustacean

Enterococci are emerging nosocomial pathogens. Their widespread distribution causes them to be food contaminants. Furthermore, Enterococci can colonize various ecological niches and diffuse into the food chain via contaminated animals and foods because of their remarkable tolerance to unfavorable environmental circumstances. Due to their potential dissemination to humans, antimicrobial-resistant Enterococci in fish are a worldwide health issue. This study characterized AMR, ARGs, VAGs, gelatinase activity, and biofilm formation in Enterococcus spp. recovered from fish and seafood and evaluated potential correlations. 54 Enterococcus spp. strains(32.73 %)were isolated from 165 samples (75 Oreochromis niloticus, 30 Argyrosomus regius, and 60 Shrimp), comprising 30 Enterococcus faecalis (55.6 %) and 24 Enterococcus faecium (44.4 %) with total 32.73 % (54/165), The maximum prevalence rate of Enterococcus spp. was observed in Nile tilapia (34/54; 63 %), followed by shrimp (14/54; 25.9 %) and Argyrosomus regius (6/54; 11.1 %). The maximum prevalence rate of E. faecalis was observed in Nile tilapia (22/30; 73.3 %), followed by shrimp (8/30; 26.7 %) with significant differences. The prevalence rate of E. faecium was observed in Nile tilapia (12/24; 50 %), followed by shrimp (6/24,25 %). E. faecium is only isolated from Argyrosomus regius (6/24,25 %). Isolates exhibited high resistance against both tetracycline (90.7 %) and erythromycin(88.9 %), followed by gentamycin (77.8 %), ciprofloxacin (74.1 %), levofloxacin (72.2 %), penicillin (44.4 %), vancomycin (37 %), and linezolid (20.4 %). 50 strains (92.6 %) exhibited resistance to more than two antibiotics, 5 strains (10 %) were XDR, and the remaining 45 strains (90 %) were classified as MDR. 92.6 % of the isolates had MARindices >0.2, indicating they originated in settings with a high risk of contamination. Additionally, ten ARGs were identified, with tet(M) 92.6 %, followed by erm(B) (88.9 %), aac(6')-Ie-aph(2″)-Ia(77.8 %), tet(K) (75.9 %), gyrA (74.1 %), blaZ (48.1 %), vanA (37 %), vanB (31.5 %), optrA (20.4 %), and catA(3.7 %). Biofilm formation and gelatinase activity were observed in 85.2 %, and 61.1 % of the isolates, respectively. A total of 11 VAGs were detected, with gelE as the most prevalent (83.3 %) followed by agg(79.6 %), pil (74.1 %), both sprE and asa1 (72.2 %), hyl (70.4 %), eps(68.5 %), EF3314 (57.4 %), ace (50 %), and cylA (35.2 %) with no detection of cylB. In conclusion, the emergence of linezolid-resistant -vancomycin-resistant enterococci recovered from Egyptian fish and shrimp, suggests that fish and seafood might participate a fundamental part in the emergence of antimicrobial resistance among humans.

Current uncertainties and challenges of publicly available pharmaceutical environmental risk assessment data

Pharmaceutical residues are widely detected in aquatic environment worldwide mainly arising from human excretions in sewage systems. Presently, publicly available, high quality environmental risk assessment (ERA) data for pharmaceuticals are limited. However, databases like the Swedish Fass offer valuable resources aiding healthcare professionals and environmental scientists in identifying substances of significant concern. In this review, we provide a concise overview of the regulatory ERA process for medicinal products intended for human use. We explore its key assumptions and uncertainties using a subset of 37 pharmaceuticals. First, we compare the consistency of their predicted no-effect concentrations reported in the Fass database with those by marketing authorisation holders. Second, we compare the predicted environmental concentrations (PEC) calculated based on sales data between European and national drug consumption statistics as well as with measured environmental concentrations (MEC), to demonstrate their impact on the regional risk quotients. Finally, we briefly discuss the prevailing uncertainties and challenges of current ecotoxicity testing, especially outcomes of chronic and nonlethal effects.

Solar-matched S-scheme ZnO/g-C3N4 for visible light-driven paracetamol degradation

In pursuit of an efficient visible light driven photocatalyst for paracetamol degradation in wastewater, we have fabricated the ZnO/g-C3N4 S-Scheme photocatalysts and explored the optimal percentage to form a composite of graphitic carbon nitride (g-C3N4) with zinc oxide (ZnO) for enhanced performance. Our study aimed to address the urgent need for a catalyst capable of environmentally friendly degradation of paracetamol, a common pharmaceutical pollutant, using visible light conditions. Here, we tailored the band gap of a photocatalyst to match solar radiation as a transformative advancement in environmental catalysis. Notably, the optimized composite, containing 10 wt.% g-C3N4 with ZnO, demonstrated outstanding paracetamol degradation efficiency of 95% within a mere 60-min exposure to visible light. This marked enhancement represented a 2.24-fold increase in the reaction rate compared to lower wt. percentage composites (3 wt.% g-C3N4) and pristine g-C3N4. The exceptional photocatalytic activity of the optimized composite can be attributed to the band gap narrowing that closely matched the maximum solar radiation spectrum. This, coupled with efficient charge transfer mechanisms through S-scheme heterojunction formation and an abundance of active sites due to increased surface area and reduced particle size, contributed to the remarkable performance. Trapping experiments identified hydroxyl radicals as the primary reactive species responsible for paracetamol photoreduction. Furthermore, the synthesized ZnO/g-C3N4 composite exhibited exceptional photostability and reusability, underscoring its practical applicability. Thus, this research marks a significant stride towards the development of an effective and sustainable visible light photocatalyst for the removal of pharmaceutical contaminants from aquatic environments.

Tackling Losartan Contamination: The Promise of Peroxymonosulfate/Fe(II) Advanced Oxidation Processes

Losartan, an angiotensin II receptor antagonist frequently detected in wastewater effluents, poses considerable risks to both aquatic ecosystems and human health. Seeking to address this challenge, advanced oxidation processes (AOPs) emerge as robust methodologies for the efficient elimination of such contaminants. In this study, the degradation of Losartan was investigated in the presence of activated peroxymonosulfate (PMS), leveraging ferrous iron as a catalyst to enhance the oxidation process. Utilizing advanced analytical techniques such as NMR and mass spectrometry, nine distinct byproducts were characterized. Notably, seven of these byproducts were identified for the first time, providing novel insights into the degradation pathway of Losartan. The study delved into the kinetics of the degradation process, assessing the degradation efficiency attained when employing the catalyst alone versus when using it in combination with PMS. The results revealed that Losartan degradation reached a significant level of 64%, underscoring the efficacy of PMS/Fe(II) AOP techniques as promising strategies for the removal of Losartan from water systems. This research not only enriches our understanding of pollutant degradation mechanisms, but also paves the way for the development of sustainable water treatment technologies, specifically targeting the removal of pharmaceutical contaminants from aquatic environments.

Would Pharmacy Students Advocate Green Pharmacy Given Their Preference for Medicines With Environmental Impact?

OBJECTIVE

To investigate the preferences among university students in Gothenburg, Sweden for medicines that have a different environmental impact with respect to effect and explore to what extent having received information about pharmaceuticals' potential harm to the environment is associated with the stated preferences.

METHODS

A survey was conducted among students in different study programs at the University of Gothenburg, Sweden. In all, 704 students received oral and written information about the study at the end of a lecture and were invited to take part (response rate: 83.5%). The questionnaire contained items about medicinal environmental information and 2 scenarios with fictious medicines as options for the treatment or symptom relief of minor ailments in humans.

RESULTS

Overall, 53.3% of the students (pharmacy students: 57.8%) had received information about the environmental impact of medicines, and 79.6% (pharmacy students: 80.6%) reported that they had concerns about the consequences. Twenty percent (pharmacy students: 9.0%) named the university as an information source. The students were most satisfied overall with the least effective and most environmentally friendly medicines. Consistently, pharmacy students gave higher scores to the most environmentally harmful medicines, especially compared with medical and health care students. Pharmacy students, who, to the same extent as medical and health care students had received information about medicines' environmental impact, were less likely to state environmentally friendly options with an inferior effect as their preferred choice.

CONCLUSION

Pharmacy students generally rated the medicines higher than other student groups, despite being aware of the harmful effects on the environment.

Environmental considerations along the life cycle of pharmaceuticals: Interview study on views regarding environmental challenges, concerns, strategies, and prospects within the pharmaceutical industry

Environmental impacts of medicines arise throughout their entire life cycle. The pharmaceutical industry has a key role in reducing these impacts in early production phases, but currently has limited possibilities to reduce the environmental exposure arising from drug consumption and end-of-life. The aim of this interview study was to explore the current environmental actions within the industry, as well as the views and attitudes toward the strategies to address the environmental challenges and concerns. Semi-structured interviews were conducted among representatives (n = 15) from twelve pharmaceutical companies operating in Finland in February-May 2021. The data were analyzed using qualitative content analysis. The representatives of pharmaceutical industry were overall well aware of the multifaceted environmental challenges related to the life cycle of pharmaceuticals and of their role in improving sustainability in production. Improving waste management and reducing impacts from companies' own operations were the most commonly mentioned actions already taking place within the companies (15/15). "Environmental impacts arising from drug consumption" (6/15) and "centralized drug manufacturing in countries with lax environmental regulation" (4/15) were most frequently brought up challenges difficult to resolve. "Development of environmentally more sustainable drug production in the company" was the most frequently raised key development need (5/15). To address this, establishment of tangible economic drivers, regulatory incentives, or reputational rewards were called for. "Incorporation of environmental aspects into decision-making in different situations" was suggested by 11/15 interviewees as a means to promote sustainable development, e.g. in selection of medicines by physicians and consumers. However, the attitudes towards the types of criteria and their evaluation differed between interviewees. Attitudes towards the "incorporation of environmental fate assessment into early phases of drug design and development" were mostly positive (10/11), suggesting that there is a keen interest in the industry to foster the introduction of new tools enabling the development of pharmaceuticals intrinsically less harmful for the environment.

Illicit Drugs in Surface Waters: How to Get Fish off the Addictive Hook

The United Nations World Drug Report published in 2022 alarmed that the global market of illicit drugs is steadily expanding in space and scale. Substances of abuse are usually perceived in the light of threats to human health and public security, while the environmental aspects of their use and subsequent emissions usually remain less explored. However, as with other human activities, drug production, trade, and consumption of drugs may leave their environmental mark. Therefore, this paper aims to review the occurrence of illicit drugs in surface waters and their bioaccumulation and toxicity in fish. Illicit drugs of different groups, i.e., psychostimulants (methamphetamines/amphetamines, cocaine, and its metabolite benzoylecgonine) and depressants (opioids: morphine, heroin, methadone, fentanyl), can reach the aquatic environment through wastewater discharge as they are often not entirely removed during wastewater treatment processes, resulting in their subsequent circulation in nanomolar concentrations, potentially affecting aquatic biota, including fish. Exposure to such xenobiotics can induce oxidative stress and dysfunction to mitochondrial and lysosomal function, distort locomotion activity by regulating the dopaminergic and glutamatergic systems, increase the predation risk, instigate neurological disorders, disbalance neurotransmission, and produce histopathological alterations in the brain and liver tissues, similar to those described in mammals. Hence, this drugs-related multidimensional harm to fish should be thoroughly investigated in line with environmental protection policies before it is too late. At the same time, selected fish species (e.g., Danio rerio, zebrafish) can be employed as models to study toxic and binge-like effects of psychoactive, illicit compounds.

Synthesis and characterization of nanocomposite based polymeric membrane (PES/PVP/GO-TiO2) and performance evaluation for the removal of various antibiotics (amoxicillin, azithromycin & ciprofloxacin) from aqueous solution

The escalating global concern regarding antibiotic pollution necessitates the development of advanced water treatment strategies. This study presents an innovative approach through the fabrication and evaluation of a Polyethersulfone (PES) membrane adorned with GO-TiO2 nanocomposites. The objective is to enhance the removal efficiency of various antibiotics, addressing the challenge of emerging organic compounds (EOCs) in water systems. The nanocomposite membranes, synthesized via the phase inversion method, incorporate hydrophilic agents, specifically GO-TiO2 nanocomposites and Polyvinylpyrrolidone (PVP). The resultant membranes underwent comprehensive characterization employing AFM, EDS, tensile strength testing, water contact angle measurements, and FESEM to elucidate their properties. Analysis revealed a substantial improvement in the hydrophilicity of the modified membranes attributed to the presence of hydroxyl groups within the GO-TiO2 structure. AFM images demonstrated an augmentation in surface roughness with increasing nanocomposite content. FESEM images unveiled structural modifications, leading to enhanced porosity and augmented water flux. The pure water flux elevated from 0.980 L/m2.h-1 for unmodified membranes to approximately 6.85 L/m2.h-1 for membranes modified with 2 wt% nanocomposites. Membrane performance analysis indicated a direct correlation between nanocomposite content and antibiotic removal efficiency, ranging from 66.52% to 89.81% with 4 wt% nanocomposite content. Furthermore, the nanocomposite-modified membrane exhibited heightened resistance to fouling. The efficacy of the membrane extended to displaying potent antibacterial properties against microbial strains, including S. aureus, E. coli, and Candida. This study underscores the immense potential of GO-TiO2 decorated PES membranes as a sustainable and efficient solution for mitigating antibiotic contamination in water systems. The utilization of nanocomposite membranes emerges as a promising technique to combat the presence of EOC pollutants, particularly antibiotics, in water bodies, thus addressing a critical environmental concern.

Fluorometric and colorimetric platforms for rapid and sensitive hydroxychloroquine detection in aqueous samples

The detection of pharmaceuticals has been an active area of research with numerous application areas ranging from therapeutic and environmental monitoring to pharmaceutical manufacturing and diagnostics. And, the emergence of COVID-19 pandemic has increased the demand for detection of certain active pharmaceutical ingredients such as Hydroxychloroquine (HCQ) mainly due to their increased manufacturing and usage. In this study, we present two optical, fluorometric and colorimetric, detection platforms for the rapid and sensitive detection of HCQ. These platforms take advantage of the interactions between the highly fluorescent dye Thioflavin T (ThT) and Tel24 G-quadruplex (G4) DNA structure, as well as the salt-induced aggregation behavior of negatively charged citrate-capped silver nanoparticles (Cit-AgNPs) in the presence of HCQ. In the fluorometric method, the addition of HCQ led to a significant and rapid decrease in the fluorescence signal of the ThT + Tel24 probe. In the colorimetric method, HCQ induced the aggregation of Cit-AgNPs in the presence of NaCl, resulting in a noticeable color change from yellowish-gray to colorless. Under the optimized conditions, the colorimetric platform exhibited a linear range of 18.0-240.0 nM and a detection limit of 9.2 nM, while the fluorometric platform showed a linear range of 0.24-5.17 μM and a detection limit of 120 nM. The selectivity of the proposed optical methods towards the target analyte was demonstrated by evaluating the response to other structurally similar small molecules. Finally, the practical applicability of both detection systems was confirmed by analyzing HCQ-spiked human urine samples that yielded average recoveries ranging from 75.4 to 110.2 % for the fluorometric platform and 86.9-98.2 % for the colorimetric platform. These results indicate the potential of the developed methods for HCQ detection in complex matrices.

Does Environmental Exposure to Pharmaceutical and Personal Care Product Residues Result in the Selection of Antimicrobial-Resistant Microorganisms, and is this Important in Terms of Human Health Outcomes?

The environment plays a critical role in the development, dissemination, and transmission of antimicrobial resistance (AMR). Pharmaceuticals and personal care products (PPCPs) enter the environment through direct application to the environment and through anthropogenic pollution. Although there is a growing body of evidence defining minimal selective concentrations (MSCs) of antibiotics and the role antibiotics play in horizontal gene transfer (HGT), there is limited evidence on the role of non-antibiotic PPCPs. Existing data show associations with the development of resistance or effects on bacterial growth rather than calculating selective endpoints. Research has focused on laboratory-based systems rather than in situ experiments, although PPCP concentrations found throughout wastewater, natural water, and soil environments are often within the range of laboratory-derived MSCs and at concentrations shown to promote HGT. Increased selection and HGT of AMR by PPCPs will result in an increase in total AMR abundance in the environment, increasing the risk of exposure and potential transmission of environmental AMR to humans. There is some evidence to suggest that humans can acquire resistance from environmental settings, with water environments being the most frequently studied. However, because this is currently limited, we recommend that more evidence be gathered to understand the risk the environment plays in regard to human health. In addition, we recommend that future research efforts focus on MSC-based experiments for non-antibiotic PPCPS, particularly in situ, and investigate the effect of PPCP mixtures on AMR. Environ Toxicol Chem 2024;43:623-636. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Chronic toxicity of pharmaceuticals to the benthic green alga Closterium ehrenbergii

Pharmaceuticals in the environment have emerged to a topic of global concern. Since these substances are designed to be biologically active, hazardous effects on non-target organisms are frequently reported. Here, the effects of five pharmaceuticals, one radiocontrast agent, and one degradation product on the freshwater green alga Closterium ehrenbergii were evaluated after chronic exposure of 168 h. Growth and maximum quantum yield (FV/FM) were used as endpoints and complemented by the assessment of morphology and chlorophyll fluorescence. We found that the tested antibiotics Ciprofloxacin and Ofloxacin impaired chloroplast integrity, resulting in a reduction of FV/FM from 0.1 mg/L. The disintegration of chloroplasts at higher concentrations (c = 0.3 and 0.8 mg/L, respectively) was visualized by brightfield and fluorescence microscopy. In contrast, Sulfamethoxazole interfered with cell division, leading to malformation of cells from 0.8 mg/L. Furthermore, the antibiotics exhibited a latency period of 72 h after which they started to reveal their true effects. Therefore, the importance of long-term toxicity testing is outlined in order to avoid underestimation of toxic effects of pharmaceuticals. Based on the EC10 values obtained, the antibiotics were considered to meet the criteria for classification as toxic to aquatic life with long lasting effects. The other test substances were found to exert no effects on C. ehrenbergii or only at very high concentrations and were classified as nontoxic.

Toxic effects of combined exposure to cadmium and diclofenac on freshwater crayfish (Procambarus clarkii): Insights from antioxidant enzyme activity, histopathology, and gut microbiome

In recent years, excessive discharge of pollutants has led to increasing concentrations of cadmium (Cd) and diclofenac (DCF) in water; however, the toxicity mechanism of combined exposure of the two pollutants to aquatic animals has not been fully studied. Procambarus clarkii is an economically important aquatic species that is easily affected by Cd and DCF. This study examined the effects of combined exposure to Cd and DCF on the tissue accumulation, physiology, biochemistry, and gut microflora of P. clarkii. The results showed that Cd and DCF accumulated in tissues in the order of hepatopancreas > gill > intestine > muscle. The hepatopancreas and intestines were subjected to severe oxidative stress, with significantly increased antioxidant enzyme activity. Pathological examination revealed lumen expansion and epithelial vacuolisation in the hepatopancreas and damage to the villous capillaries and wall in the intestine. The co-exposure to Cadmium (Cd) and Diclofenac (DCF) disrupts the Firmicutes/Bacteroidetes (F/B) ratio, impairing the regular functioning of intestinal microbiota in carbon (C) and nitrogen (N) cycling. This disturbance consequently hinders the absorption and utilization of energy and nutrients in Procambarus clarkii. This study offers critical insights into the toxicological mechanisms underlying the combined effects of Cd and DCF, and suggests potential approaches to alleviate their adverse impacts on aquatic ecosystems.

Metagenomic insights into microorganisms and antibiotic resistance genes of waste antibiotic fermentation residues along production, storage and treatment processes

Antibiotic fermentation residue (AFR) is nutrient-rich solid waste generated from fermentative antibiotic production process. It is demonstrated that AFR contains high-concentration of remaining antibiotics, and thus may promote antibiotic resistance development in receiving environment or feeding farmed animals. However, the dominate microorganisms and antibiotic resistance genes (ARGs) in AFRs have not been adequately explored, hampering understanding on the potential antibiotic resistance risk development caused by AFRs. Herein, seven kinds of representative AFRs along their production, storage, and treatment processes were collected, and multiple methods including amplicon sequencing, metagenomic sequencing, and bioinformatic approaches were adopted to explore the biological characteristics of AFRs. As expected, antibiotic fermentation producer was found as the predominant species in raw AFRs, which were collected at the outlet of fermentation tanks. However, except for producer species, more environment-derived species persisted in stored AFRs, which were temporarily stored at a semi-open space. Lactobacillus genus, classified as Firmicutes phylum and Bacilli class, became predominant bacterial taxa in stored AFRs, which might attribute to its tolerance to high concentration of antibiotics. Results from metagenomic sequencing together with assembly and binning approaches showed that these newly-colonizing species (e.g., Lactobacillus genus) tended to carry ARGs conferring resistance to the remaining antibiotic. However, after thermal treatment, remaining antibiotic could be efficiently removed from AFRs, and microorganisms together with DNA could be strongly destroyed. In sum, the main risk from the AFRs was the remaining antibiotic, while environment-derived bacteria which tolerate extreme environment, survived in ARFs with high content antibiotics, and may carry ARGs. Thus, hydrothermal or other harmless treatment technologies are recommended to remove antibiotic content and inactivate bacteria before recycling of AFRs in pharmaceutical industry.

Dissemination of mcr-1 and β-lactamase genes among Pseudomonas aeruginosa: molecular characterization of MDR strains in broiler chicks and dead-in-shell chicks infections

OBJECTIVES

Pseudomonas aeruginosa (P. aeruginosa) is one of the most serious pathogens implicated in antimicrobial resistance, and it has been identified as an ESKAPE along with other extremely significant multidrug resistance pathogens. The present study was carried out to explore prevalence, antibiotic susceptibility phenotypes, virulence-associated genes, integron (int1), colistin (mcr-1), and β-lactamase resistance' genes (ESBls), as well as biofilm profiling of P. aeruginosa isolated from broiler chicks and dead in-shell chicks.

DESIGN

A total of 300 samples from broiler chicks (n = 200) and dead in-shell chicks (n = 100) collected from different farms and hatcheries located at Mansoura, Dakahlia Governorate, Egypt were included in this study. Bacteriological examination was performed by cultivation of the samples on the surface of both Cetrimide and MacConkey's agar. Presumptive colonies were then subjected to biochemical tests and Polymerase Chain Reaction (PCR) targeting 16S rRNA. The recovered isolates were tested for the presence of three selected virulence-associated genes (lasB, toxA, and exoS). Furthermore, the retrieved isolates were subjected to phenotypic antimicrobial susceptibility testing by Kirby-Bauer disc diffusion method as well as phenotypic detection of ESBLs by both Double Disc Synergy Test (DDST) and the Phenotypic Confirmatory Disc Diffusion Test (PCDDT). P. aeruginosa isolates were then tested for the presence of antibiotic resistance genes (ARGs): int1, mcr-1, and ESBL genes (OXA-10, OXA-2, VEB-1, SHV, TEM, and CTX-M). Additionally, biofilm production was examined by the Tube Adherent method (TA) and Microtiter Plate assay (MTP).

RESULTS

Fifty -five isolates were confirmed to be P. aeruginosa, including 35 isolates from broiler chicks and 20 isolates from dead in-shell chicks. The three tested virulence genes (lasB, toxA, and exoS) were detected in all isolates. Antibiogram results showed complete resistance against penicillin, amoxicillin, ceftriaxone, ceftazidime, streptomycin, erythromycin, spectinomycin, and doxycycline, while a higher sensitivity was observed against meropenem, imipenem, colistin sulfate, ciprofloxacin, and gentamicin. ESBL production was confirmed in 12 (21.8%) and 15 (27.3%) isolates by DDST and PCDDT, respectively. Antibiotic resistance genes (ARGs): int1, mcr-1, and ESBL genes (OXA-10, SHV, TEM, and CTX-M), were detected in 87.3%, 18.2%, 16.4%, 69.1%, 72.7%, and 54.5% of the examined isolates respectively, whereas no isolate harbored the OXA-2 or VEB-1 genes. Based on the results of both methods used for detection of biofilm formation, Kappa statistics [kappa 0.324] revealed a poor agreement between both methods.

CONCLUSIONS

the emergence of mcr-1 and its coexistence with other resistance genes such as β-lactamase genes, particularly blaOXA-10, for the first time in P. aeruginosa from young broiler chicks and dead in-shell chicks in Egypt pose a risk not only to the poultry industry but also to public health.

Antibiotic persistence and its impact on the environment

From boon molecules to molecules contributing to rising concern has been the sojourn of antibiotics. The problem of antibiotic contamination has gotten worse due to antibiotics' pervasive use in every aspect of the environment. One such consequence of pollution is the increase in infections with antibiotic resistance. All known antimicrobials being used for human benefit lead to their repetitive and routine release into the environment. The misuse of antibiotics has aggravated the situation to a level that we are short of antibiotics to treat infections as organisms have developed resistance against them. Overconsumption is not just limited to human health care, but also occurs in other areas such as aquaculture, livestock, and veterinary applications for the purpose of improving feed and meat products. Due to their harmful effects on non-target species, the trace level of antibiotics in the aquatic ecosystem presents a significant problem. Since the introduction of antibiotics into the environment is more than their removal, they have been given the status of persistent pollutants. The buildup of antibiotics in the environment threatens aquatic life and may lead to bacterial strains developing resistance. As newer organisms are becoming resistant, there exists a shortage of antibiotics to treat infections. This has presented a very critical problem for the health-care community. Another rising concern is that the development of newer drug molecules as antibiotics is minimal. This review article critically explains the cause and nature of the pollution and the effects of this emerging trend. Also, in the latter sections, why we need newer antibiotics is questioned and discussed.

Using intersectionality to study gender and antimicrobial resistance in low- and middle-income countries

Different sexes and genders experience differentiated risks of acquiring infections, including drug-resistant infections, and of becoming ill. Different genders also have different health-seeking behaviours that shape their likelihood of having access to and appropriately using and administering antimicrobials. Consequently, they are distinctly affected by antimicrobial resistance (AMR). As such, it is crucial to incorporate perspectives on sex and gender in the study of both AMR and antimicrobial use in order to present a full picture of AMR's drivers and impact. An intersectional approach to understanding gender and AMR can display how gender and other components 'intersect' to shape the experiences of individuals and groups affected by AMR. However, there are insufficient data on the burden of AMR disaggregated by gender and other socio-economic characteristics, and where available, it is fragmented. For example, to date, the best estimate of the global burden of bacterial AMR published in The Lancet does not consider gender or other social stratifiers in its analysis. To address this evidence gap, we undertook a scoping review to examine how sex and gender compounded by other axes of marginalization influence one's vulnerability and exposure to AMR as well as one's access to and use of antimicrobials. We undertook a gendered analysis of AMR, using intersectionality as a concept to help us understand the multiple and overlapping ways in which different people experience exposure vulnerability to AMR. This approach is crucial in informing a more nuanced view of the burden and drivers of AMR. The intersectional gender lens should be taken into account in AMR surveillance, antimicrobial stewardship, infection prevention and control and public and professional awareness efforts, both donor and government funded, as well as national and international policies and programmes tackling AMR such as through national action plans.

Contribution of wastewater to antimicrobial resistance: A review article

OBJECTIVES

Antimicrobial resistance (AMR) is a global challenge that has raised concern globally, owing to its detrimental effects on the health and economy of countries. The ever-growing threat of AMR and sources of AMR are still being investigated. Wastewater plays an important role as a habitat for bacteria and an environment conducive to gene transfer. The primary aim of this review was to highlight the contribution of wastewater to AMR.

METHODS

Evidence of AMR in wastewater was drawn from literature published in the last 10 years, from 2012 to 2022.

RESULTS

Wastewater from agricultural practices, pharmaceutical manufacturing plants, and hospital effluents was established to promote AMR. Furthermore, stress factors such as the presence of antibiotics, heavy metals, pH, and temperature initiate and propagate AMR in bacteria living in wastewater. AMR in bacteria from wastewater was established to be either natural or acquired. Wastewater treatment techniques such as membrane filtration, coagulation, adsorption, and advanced oxidation processes have been used to remove resistant bacteria with varying success levels.

CONCLUSION

Wastewater is a major contributor to AMR, and an understanding of its role in AMR is necessary to find a lasting solution. In this regard, the spread of AMR in wastewater should be considered a threat that requires a strategy to stop further damage.

Photocatalytic degradation of four emerging antibiotic contaminants and toxicity assessment in wastewater: A comprehensive study

Excessive usage and unrestricted discharge of antibiotics in the environment lead to their accumulation in the ecosystem due to their highly stable and non-biodegradation nature. Photodegradation of four most consumed antibiotics such as amoxicillin, azithromycin, cefixime, and ciprofloxacin were studied using Cu2O-TiO2 nanotubes. Cytotoxicity evaluation of the native and transformed products was conducted on the RAW 264.7 cell lines. Photocatalyst loading (0.1-2.0 g/L), pH (5, 7 and 9), initial antibiotic load (50-1000 μg/mL) and cuprous oxide percentage (5, 10 and 20) were optimized for efficient photodegradation of antibiotics. Quenching experiments to evaluate the mechanism of photodegradation with hydroxyl and superoxide radicals were found the most reactive species of the selected antibiotics. Complete degradation of selected antibiotics was achieved in 90 min with 1.5 g/L of 10% Cu2O-TiO2 nanotubes with initial antibiotic concentration (100 μg/mL) at neutral pH of water matrix. The photocatalyst showed high chemical stability and reusability up to five consecutive cycles. Zeta potential studies confirms the high stability and activity of 10% C-TAC (Cuprous oxide doped Titanium dioxide nanotubes for Applied Catalysis) in the tested pH conditions. Photoluminescence and Electrochemical Impedance Spectroscopy data speculates that 10% C-TAC photocatalyst have efficient photoexcitation in the visible light for photodegradation of antibiotics samples. Inhibitory concentration (IC50) interpretation from the toxicity analysis of native antibiotics concluded that ciprofloxacin was the most toxic antibiotic among the selected antibiotics. Cytotoxicity percentage of transformed products showed r: -0.985, p: 0.01 (negative correlation) with the degradation percentage revealing the efficient degradation of selected antibiotics with no toxic by-products.

Towards monitoring of antimicrobial resistance in the environment: For what reasons, how to implement it, and what are the data needs?

Antimicrobial resistance (AMR) is a global threat to human and animal health and well-being. To understand AMR dynamics, it is important to monitor resistant bacteria and resistance genes in all relevant settings. However, while monitoring of AMR has been implemented in clinical and veterinary settings, comprehensive monitoring of AMR in the environment is almost completely lacking. Yet, the environmental dimension of AMR is critical for understanding the dissemination routes and selection of resistant microorganisms, as well as the human health risks related to environmental AMR. Here, we outline important knowledge gaps that impede implementation of environmental AMR monitoring. These include lack of knowledge of the 'normal' background levels of environmental AMR, definition of high-risk environments for transmission, and a poor understanding of the concentrations of antibiotics and other chemical agents that promote resistance selection. Furthermore, there is a lack of methods to detect resistance genes that are not already circulating among pathogens. We conclude that these knowledge gaps need to be addressed before routine monitoring for AMR in the environment can be implemented on a large scale. Yet, AMR monitoring data bridging different sectors is needed in order to fill these knowledge gaps, which means that some level of national, regional and global AMR surveillance in the environment must happen even without all scientific questions answered. With the possibilities opened up by rapidly advancing technologies, it is time to fill these knowledge gaps. Doing so will allow for specific actions against environmental AMR development and spread to pathogens and thereby safeguard the health and wellbeing of humans and animals.

Removal of the Water Pollutant Ciprofloxacin Using Biodegradable Sorbent Polymers Obtained from Polysaccharides

Water use has been increasing globally by 1% per year, and recycling and re-use are critical issues compromised by the presence of pollutants. In this context, the design of novel materials and/or procedures for the large scale-removal of pollutants must be economically and environmentally feasible in order to be considered as part of the solution by emerging economies. We demonstrate that the cross-linking of biodegradable polysaccharides such as starch, dextrin, or dextrin and β-cyclodextrin with divinyl sulfone is an innovative strategy for synthesizing insoluble and eco-friendly sorbent polymers, including pSt, pDx and pCD-Dx. The evaluation of these polymers' ability to remove ciprofloxacin (CIP), a prime example of antibiotic pollution, revealed that pSt, with a Kd of 1469 L/kg and a removal rate higher than 92%, is a favorable material. Its sorption is pH-dependent and enhanced at a mildly alkaline pH, allowing for the desorption (i.e., cleaning) and reuse of pSt through an environmentally friendly treatment with 20 mM AcONa pH 4.6. The facts that pSt (i) shows a high affinity for CIP even at high NaCl concentrations, (ii) can be obtained from affordable starting materials, and (iii) is synthesized and regenerated through organic, solvent-free procedures make pSt a novel sustainable material for inland water and seawater remediation, especially in less developed countries, due to its simplicity and low cost.

Assessment of selected pharmaceuticals in Riyadh wastewater treatment plants, Saudi Arabia: Mass loadings, seasonal variations, removal efficiency and environmental risk

Despite increasing interest in pharmaceutical emissions worldwide, studies of environmental contamination with pharmaceuticals arising from wastewater discharges in Saudi Arabia are scarce. Therefore, this study examined occurrence, mass loads and removal efficiency for 15 pharmaceuticals and one metabolite (oxypurinol) from different therapeutic classes in three wastewater treatment plants (WWTPs), in Riyadh city in Saudi Arabia. A total of 144 samples were collected from the influents and effluents between March 2018 and July 2019 and analyzed using Solid Phase Extraction followed by triple quadrupole LC-MS/MS. The average concentrations in the influents and effluents were generally higher than their corresponding concentrations found either in previous Saudi Arabian or global studies. The four most dominant compounds in the influent were acetaminophen, ciprofloxacin, caffeine, and diclofenac, with caffeine and acetaminophen having the highest concentrations ranging between 943 and 2282 μg/L. Metformin and ciprofloxacin were the most frequently detected compounds in the effluents at concentrations as high as 33.2 μg/L. Ciprofloxacin had the highest mass load in the effluents of all three WWTPs, ranging between 0.20 and 20.7 mg/day/1000 inhabitants for different WWTPs. The overall average removal efficiency was estimated high (≥80), with no significant different (p > 0.05) between the treatment technology applied. Acetaminophen and caffeine were almost completely eliminated in all three WWTPs. The samples collected in the cold season generally had higher levels of detected compounds than those from the warm seasons, particularly for NSAID and antibiotic compounds. The estimated environmental risk from pharmaceutical compounds in the studied effluents was mostly low, except for antibiotic compounds. Thus, antibiotics should be considered for future monitoring programmes of the aquatic environment in Saudi Arabia.

Ligninolytic enzyme activity and removal efficiency of pharmaceuticals in a water matrix by fungus Rhizopus sp. Isolated from cassava

Residual amounts of pharmaceutical compounds (PhCs) and by-products are continually released into surface water with effluents from conventional wastewater treatment plants (WWTPs). This study evaluated the ability of fungal isolate to remove selected PhCs [carbamazepine (CBZ), diclofenac (DCF) and ibuprofen (IBP)] from wastewater. The fungus used was Rhizopus sp. which was isolated from tuberous roots of cassava (Manihot esculenta). The isolate exhibited an important removal efficiency up to 100% and this was linked to ligninolytic enzymatic activity for lignin peroxidase (15.29 ± 2.69U/L) and manganese peroxidase (85.22 ± 4.26U/L), except laccase. This activity was optimum on day 9 of treatment. PhC metabolites were identified during the experiment revealing the existence of a biotransformation process catalysed by the isolated fungus. The disappearance of PhCs was attributed to their biosorption and biotransformation. However, it was not possible to establish a relationship between the ligninolytic enzymatic activity and the removal efficiency, which leads to the conclusion that there are other fungal metabolites which also play an important role in the biotransformation and biodegradation of the selected PhCs.

Lignocellulosic residues from bioethanol production: a novel source of biopolymers for laccase immobilization

The full utilization of the main components in the lignocellulosic biomass is the major goal from a biorefinery point of view, giving not only environmental benefits but also making the process economically viable. In this sense the solid residue obtained in bioethanol production after steam explosion pretreatment, enzymatic hydrolysis, and fermentation of the lignocellulosic biomass, was studied for further valorization. Two different residues were analyzed, one generated by the production of cellulosic ethanol from an energy crop such as switchgrass (Panicum virgatum) and the other, from wood (Eucalyptus globulus). The chemical composition of these by-products showed that they were mainly composed of lignin with a total content range from 70 to 83% (w/w) and small amounts of cellulose and hemicellulose. The present work was focused on devising a new alternative for processing these materials, based on the ability of the ionic liquids (IL) to dissolve lignocellulosic biomass. The resulting mixture of biopolymers and IL constituted the raw material for developing new insoluble biocatalysts. Active hydrogels based on fungal laccase from Dichostereum sordulentum 1488 were attained. A multifactorial analysis of the main variables involved in the immobilization process enabled a more direct approach to improving hydrogel-bound activity. These hydrogels achieved a 97% reduction in the concentration of the estrogen ethinylestradiol, an emerging contaminant of particular concern due to its endocrine activity. The novel biocatalysts based on fungal laccase entrapped on a matrix made from a by-product of second-generation bioethanol production presents great potential for performing heterogeneous catalysis offering extra value to the ethanol biorefinery.

Spatial Distribution and Risk Assessment of Antibiotics in 15 Pharmaceutical Plants in the Pearl River Delta

Pharmaceutical plants are an essential source of antibiotics emitted into the aqueous environment. The monitoring of target antibiotics in pharmaceutical plants through various regions is vital to optimize contaminant release. The occurrence, distribution, removal, and ecological risk of 30 kinds of selected antibiotics in 15 pharmaceutical plants in the Pearl River Delta (PRD) were investigated in this study. Lincomycin (LIN) showed the highest concentration (up to 56,258.3 ng/L) in the pharmaceutical plant influents from Zhongshan city. Norfloxacin (NFX) showed a higher detection frequency than other antibiotics. In addition, the spatial distribution of antibiotics in pharmaceutical plants showed significant differences, with higher concentrations of total antibiotics found in pharmaceutical plant influents in Shenzhen City than those of different regions in PRD. The treatment processes adopted by pharmaceutical plants were commonly ineffective in removing antibiotics, with only 26.7% of antibiotics being effectively removed (average removal greater than 70%), while 55.6% of antibiotics had removal rates of below 60%. The anaerobic/anoxic/oxic (AAO)-membrane bioreactor (MBR) combined process exhibited better treatment performance than the single treatment process. Sulfamethoxazole (SMX), ofloxacin (OFL), erythromycin-H₂O (ETM-H₂O), sulfadiazine (SDZ), sulfamethazine (SMZ), norfloxacin (NFX), and ciprofloxacin (CIP) in pharmaceutical plant effluents posed high or moderate ecological risk and deserve particular attention.

Fish liver damage related to the wastewater treatment plant effluents

Wastewater treatment plants (WWTPs) continuously release a complex mixture of municipal, hospital, industrial, and runoff chemicals into the aquatic environment. These contaminants are both legacy contaminants and emerging-concern contaminants, affecting all tissues in a fish body, particularly the liver. The fish liver is the principal detoxifying organ and effects of consistent pollutant exposure can be evident on its cellular and tissue level. The objective of this paper is thus to provide an in-depth analysis of the WWTP contaminants' impact on the fish liver structure, physiology, and metabolism. The paper also gives an overview of the fish liver biotransformation enzymes, antioxidant enzymes, and non-enzymatic antioxidants, their role in metabolizing xenobiotic compounds and coping with oxidative damage. Emphasis has been placed on highlighting the vulnerability of fish to xenobiotic compounds, and on biomonitoring of exposed fish, generally involving observation of biomarkers in caged or native fish. Furthermore, the paper systematically assesses the most common contaminants with the potential to affect fish liver tissue.

Evidence for wastewaters as environments where mobile antibiotic resistance genes emerge

The emergence and spread of mobile antibiotic resistance genes (ARGs) in pathogens have become a serious threat to global health. Still little is known about where ARGs gain mobility in the first place. Here, we aimed to collect evidence indicating where such initial mobilization events of clinically relevant ARGs may have occurred. We found that the majority of previously identified origin species did not carry the mobilizing elements that likely enabled intracellular mobility of the ARGs, suggesting a necessary interplay between different bacteria. Analyses of a broad range of metagenomes revealed that wastewaters and wastewater-impacted environments had by far the highest abundance of both origin species and corresponding mobilizing elements. Most origin species were only occasionally detected in other environments. Co-occurrence of origin species and corresponding mobilizing elements were rare in human microbiota. Our results identify wastewaters and wastewater-impacted environments as plausible arenas for the initial mobilization of resistance genes.

Emissions of pharmaceuticals and plant protection products to the lagoon of Venice: development of a new emission inventory

Estimating the emissions of chemical pollutants to water is a fundamental step for the development and application of effective and sustainable management strategies of water resources, but methods applied so far to build chemicals inventories at the European or national scale show several limitations when applied at the local scale. The issue is particularly relevant when considering contaminants of emerging concern (CECs), whose environmental releases and occurrence are still poorly studied and understood. In this work, an approach to estimate water emissions of nine active pharmaceutical ingredients (APIs) and ten most applied plant protection products (PPPs) is presented, considering proxy indicators (e.g., sales data and census information). The application area is the lagoon of Venice (Italy), a complex transitional environment highly influenced by anthropic pressures (e.g., agricultural and industrial activities, animal breeding, and wastewater discharge). The presented approach can be tailored to the information available for any local scale case study. Data on annual regional sales of PPPs and APIs were integrated with georeferenced demographic and economic statistics (such as census and land-use information) to estimate chemicals emissions to surface water and groundwater. A sensitivity and uncertainty analysis identified the main factors affecting emissions estimates, and those contributing more significantly to results uncertainty. Results showed the highest estimated emissions of APIs for antibiotics (i.e., amoxicillin, clarithromycin, azithromycin, and ciprofloxacin) used for humans and animals, while most of hormones' emission (i.e., 17- α-ethinylestradiol and 17-β-estradiol) derived from animal breeding. Regarding PPPs, glyphosate and imidacloprid emissions were one to two orders of magnitude higher compared to the other chemicals. Uncertainty and sensitivity analysis showed that the variability of each parameter used to estimate emissions depends greatly both on the target chemical and the specific emission source considered. Excretion rates and removal during wastewater treatment were major key parameters for all the target pharmaceutical compounds, while for PPPs the key parameter was their loss into the natural waters after application.

Latent antibiotic resistance genes are abundant, diverse, and mobile in human, animal, and environmental microbiomes

BACKGROUND

Bacterial communities in humans, animals, and the external environment maintain a large collection of antibiotic resistance genes (ARGs). However, few of these ARGs are well-characterized and thus established in existing resistance gene databases. In contrast, the remaining latent ARGs are typically unknown and overlooked in most sequencing-based studies. Our view of the resistome and its diversity is therefore incomplete, which hampers our ability to assess risk for promotion and spread of yet undiscovered resistance determinants.

RESULTS

A reference database consisting of both established and latent ARGs (ARGs not present in current resistance gene repositories) was created. By analyzing more than 10,000 metagenomic samples, we showed that latent ARGs were more abundant and diverse than established ARGs in all studied environments, including the human- and animal-associated microbiomes. The pan-resistomes, i.e., all ARGs present in an environment, were heavily dominated by latent ARGs. In comparison, the core-resistome, i.e., ARGs that were commonly encountered, comprised both latent and established ARGs. We identified several latent ARGs shared between environments and/or present in human pathogens. Context analysis of these genes showed that they were located on mobile genetic elements, including conjugative elements. We, furthermore, identified that wastewater microbiomes had a surprisingly large pan- and core-resistome, which makes it a potentially high-risk environment for the mobilization and promotion of latent ARGs.

CONCLUSIONS

Our results show that latent ARGs are ubiquitously present in all environments and constitute a diverse reservoir from which new resistance determinants can be recruited to pathogens. Several latent ARGs already had high mobile potential and were present in human pathogens, suggesting that they may constitute emerging threats to human health. We conclude that the full resistome-including both latent and established ARGs-needs to be considered to properly assess the risks associated with antibiotic selection pressures. Video Abstract.

Neuroactive pharmaceuticals in estuaries: Occurrence and tissue-specific bioaccumulation in multiple fish species

Contamination of surface waters by pharmaceuticals is an emerging problem globally. This is because the increased access and use of pharmaceuticals by a growing world population lead to environmental contamination, threatening non-target species in their natural environment. Of particular concern are neuroactive pharmaceuticals, which are known to bioaccumulate in fish and impact a variety of individual processes such as fish reproduction or behaviour, which can have ecological impacts and compromise fish populations. In this work, we investigate the occurrence and bioaccumulation of 33 neuroactive pharmaceuticals in brain, muscle and liver tissues of multiple fish species collected in four different estuaries (Douro, Tejo, Sado and Mira). In total, 28 neuroactive pharmaceuticals were detected in water and 13 in fish tissues, with individual pharmaceuticals reaching maximum concentrations of 1590 ng/L and 207 ng/g ww, respectively. The neuroactive pharmaceuticals with the highest levels and highest frequency of detection in the water samples were psychostimulants, antidepressants, opioids and anxiolytics, whereas in fish tissues, antiepileptics, psychostimulants, anxiolytics and antidepressants showed highest concentrations. Bioaccumulation was ubiquitous, occurring in all seven estuarine and marine fish species. Notably, neuroactive compounds were detected in every water and fish brain samples, and in 95% of fish liver and muscle tissues. Despite variations in pharmaceutical occurrence among estuaries, bioaccumulation patterns were consistent among estuarine systems, with generally higher bioaccumulation in fish brain followed by liver and muscle. Moreover, no link between bioaccumulation and compounds' lipophilicity, species habitat use patterns or trophic levels was observed. Overall, this work highlights the occurrence of a highly diverse suite of neuroactive pharmaceuticals and their pervasiveness in waters and fish from estuarine systems with contrasting hydromorphology and urban development and emphasizes the urgent need for toxicity assessment of these compounds in natural ecosystems, linked to internalized body concentration in non-target species.

Modelling the synergistic effect of bacteriophage and antibiotics on bacteria: Killers and drivers of resistance evolution

Bacteriophage (phage) are bacterial predators that can also spread antimicrobial resistance (AMR) genes between bacteria by generalised transduction. Phage are often present alongside antibiotics in the environment, yet evidence of their joint killing effect on bacteria is conflicted, and the dynamics of transduction in such systems are unknown. Here, we combine in vitro data and mathematical modelling to identify conditions where phage and antibiotics act in synergy to remove bacteria or drive AMR evolution. We adapt a published model of phage-bacteria dynamics, including transduction, to add the pharmacodynamics of erythromycin and tetracycline, parameterised from new in vitro data. We simulate a system where two strains of Staphylococcus aureus are present at stationary phase, each carrying either an erythromycin or tetracycline resistance gene, and where multidrug-resistant bacteria can be generated by transduction only. We determine rates of bacterial clearance and multidrug-resistant bacteria appearance, when either or both antibiotics and phage are present at varying timings and concentrations. Although phage and antibiotics act in synergy to kill bacteria, by reducing bacterial growth antibiotics reduce phage production. A low concentration of phage introduced shortly after antibiotics fails to replicate and exert a strong killing pressure on bacteria, instead generating multidrug-resistant bacteria by transduction which are then selected for by the antibiotics. Multidrug-resistant bacteria numbers were highest when antibiotics and phage were introduced simultaneously. The interaction between phage and antibiotics leads to a trade-off between a slower clearing rate of bacteria (if antibiotics are added before phage), and a higher risk of multidrug-resistance evolution (if phage are added before antibiotics), exacerbated by low concentrations of phage or antibiotics. Our results form hypotheses to guide future experimental and clinical work on the impact of phage on AMR evolution, notably for studies of phage therapy which should investigate varying timings and concentrations of phage and antibiotics.

Machine learning-assisted evaluation of potential biochars for pharmaceutical removal from water

A popular approach to select optimal adsorbents is to perform parallel experiments on adsorbents based on an initially decided goal such as specified product purity, efficiency, or binding capacity. To screen optimal adsorbents, we focused on the max adsorption capacity of the candidates at equilibrium in this work because the adsorption capacity of each adsorbent is strongly dependent on certain conditions. A data-driven machine learning tool for predicting the max adsorption capacity (Q_m) of 19 pharmaceutical compounds on 88 biochars was developed. The range of values of Q_m (mean 48.29 mg/g) was remarkably large, with a high number of outliers and large variability. Modified biochars enhanced the Q_m and surface area values compared with the original biochar, with a statistically significant difference (Chi-square value = 7.21-18.25, P < 0.005). K- nearest neighbors (KNN) was found to be the most optimal algorithm with a root mean square error (RMSE) of 23.48 followed by random forest and Cubist with RMSE of 26.91 and 29.56, respectively, whereas linear regression and regularization were the worst algorithms. KNN model achieved R² of 0.92 and RMSE of 16.62 for the testing data. A web app was developed to facilitate the use of the KNN model, providing a reliable solution for saving time and money in unnecessary lab-scale adsorption experiments while selecting appropriate biochars for pharmaceutical adsorption.

Risk assessment of selected pharmaceuticals on wildlife with nanomaterials based aptasensors

Pharmaceuticals have improved human and veterinary health tremendously over the years. But the implications of the presence of pharmaceuticals in the environment on terrestrial, avian, and aquatic organisms are still not fully comprehended. The bioaccumulation and biomagnifications of these chemicals through the food chain have long-term effects on the wildlife. The detection and quantification of such pharmaceutical residues in the environment is a tedious process and quicker methods are needed. Aptasensors are one such quick and reliable method for the identification of pharmaceutical residues in the wildlife. Aptasensors are a class of biosensors that work on the principles of biological recognition of elements. The aptamers are unique biological recognition elements with high specificity and affinity to various targets. Their efficiency makes them a very promising candidate for such sensitive research. In this review, the pharmaceutical threats to wildlife and their detection techniques using aptasensors have been discussed.

Advocacy for Responsible Antibiotic Production and Use

Antibiotic-resistant bacteria have become one of humankind’s major challenges, as testified by the UN’s Call to Action on Antimicrobial Resistance in 2021. Our knowledge of the underlying processes of antibiotic resistance is steadily improving. Beyond the inappropriate use of antimicrobials in human medicine, other causes have been identified, raising ethical issues and requiring an approach to the problem from a “One Health” perspective. Indeed, it is now clear that the two main issues regarding the subject of antibiotics are their misuse in the global food industry and their method of production, both leading to the emergence and spread of bacterial resistance.

Antimicrobial Resistance Monitoring of Water Environments: A Framework for Standardized Methods and Quality Control

Antimicrobial resistance (AMR) is a grand societal challenge with important dimensions in the water environment that contribute to its evolution and spread. Environmental monitoring could provide vital information for mitigating the spread of AMR; this includes assessing antibiotic resistance genes (ARGs) circulating among human populations, identifying key hotspots for evolution and dissemination of resistance, informing epidemiological and human health risk assessment models, and quantifying removal efficiencies by domestic wastewater infrastructure. However, standardized methods for monitoring AMR in the water environment will be vital to producing the comparable data sets needed to address such questions. Here we sought to establish scientific consensus on a framework for such standardization, evaluating the state of the science and practice of AMR monitoring of wastewater, recycled water, and surface water, through a literature review, survey, and workshop leveraging the expertise of academic, governmental, consulting, and water utility professionals.

Antimicrobial Resistance Monitoring of Water Environments: A Framework for Standardized Methods and Quality Control

Antimicrobial resistance (AMR) is a grand societal challenge with important dimensions in the water environment that contribute to its evolution and spread. Environmental monitoring could provide vital information for mitigating the spread of AMR; this includes assessing antibiotic resistance genes (ARGs) circulating among human populations, identifying key hotspots for evolution and dissemination of resistance, informing epidemiological and human health risk assessment models, and quantifying removal efficiencies by domestic wastewater infrastructure. However, standardized methods for monitoring AMR in the water environment will be vital to producing the comparable data sets needed to address such questions. Here we sought to establish scientific consensus on a framework for such standardization, evaluating the state of the science and practice of AMR monitoring of wastewater, recycled water, and surface water, through a literature review, survey, and workshop leveraging the expertise of academic, governmental, consulting, and water utility professionals.

Antimicrobial Resistance Development Pathways in Surface Waters and Public Health Implications

Human health is threatened by antibiotic-resistant bacteria and their related infections, which cause thousands of human deaths every year worldwide. Surface waters are vulnerable to human activities and natural processes that facilitate the emergence and spread of antibiotic-resistant bacteria in the environment. This study evaluated the pathways and drivers of antimicrobial resistance (AR) in surface waters. We analyzed antibiotic resistance healthcare-associated infection (HAI) data reported to the CDC's National Healthcare Safety Network to determine the number of antimicrobial-resistant pathogens and their isolates detected in healthcare facilities. Ten pathogens and their isolates associated with HAIs tested resistant to the selected antibiotics, indicating the role of healthcare facilities in antimicrobial resistance in the environment. The analyzed data and literature research revealed that healthcare facilities, wastewater, agricultural settings, food, and wildlife populations serve as the major vehicles for AR in surface waters. Antibiotic residues, heavy metals, natural processes, and climate change were identified as the drivers of antimicrobial resistance in the aquatic environment. Food and animal handlers have a higher risk of exposure to resistant pathogens through ingestion and direct contact compared with the general population. The AR threat to public health may grow as pathogens in aquatic systems adjust to antibiotic residues, contaminants, and climate change effects. The unnecessary use of antibiotics increases the risk of AR, and the public should be encouraged to practice antibiotic stewardship to decrease the risk.

Antimicrobial Resistance in New Zealand-A One Health Perspective

Antimicrobial resistance (AMR) is an increasing global threat that affects human, animal and, often less acknowledged, environmental health. This complex issue requires a multisectoral One Health approach to address the interconnectedness of humans, animals and the natural environment. The prevalence of AMR in these reservoirs varies widely among countries and thus often requires a country-specific approach. In New Zealand (NZ), AMR and antimicrobial usage in humans are relatively well-monitored and -understood, with high human use of antimicrobials and the frequency of resistant pathogens increasing in hospitals and the community. In contrast, on average, NZ is a low user of antimicrobials in animal husbandry systems with low rates of AMR in food-producing animals. AMR in New Zealand’s environment is little understood, and the role of the natural environment in AMR transmission is unclear. Here, we aimed to provide a summary of the current knowledge on AMR in NZ, addressing all three components of the One Health triad with a particular focus on environmental AMR. We aimed to identify knowledge gaps to help develop research strategies, especially towards mitigating AMR in the environment, the often-neglected part of the One Health triad.