Algae blooms with resistance in fresh water: Potential interplay between Microcystis and antibiotic resistance genes. - Related Documents




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643701.0000Algae blooms with resistance in fresh water: Potential interplay between Microcystis and antibiotic resistance genes. Microcystis, a type of cyanobacteria known for producing microcystins (MCs), is experiencing a global increase in blooms. They have been recently recognized as potential contributors to the widespread of antibiotic resistance genes (ARGs). By reviewing approximately 150 pieces of recent studies, a hypothesis has been formulated suggesting that significant fluctuations in MCs concentrations and microbial community structure during Microcystis blooms could influence the dynamics of waterborne ARGs. Among all MCs, microcystin-LR (MC-LR) is the most widely distributed worldwide, notably abundant in reservoirs during summer. MCs inhibit protein phosphatases or increase reactive oxygen species (ROS), inducing oxidative stresses, enhancing membrane permeability, and causing DNA damage. This further enhances selective pressures and horizontal gene transfer (HGT) chances of ARGs. The mechanisms by which Microcystis regulates ARG dissemination have been systematically organized for the first time, focusing on the secretion of MCs and the alterations of bacterial community structure. However, several knowledge gaps remain, particularly concerning how MCs interfere with the electron transport chain and how Microcystis facilitates HGT of ARGs. Concurrently, the predominance of Microcystis forming the algal microbial aggregates is considered a hotspot for preserving and transferring ARGs. Yet, Microcystis can deplete the nutrients from other taxa within these aggregates, thereby reducing the density of ARG-carrying bacteria. Therefore, further studies are needed to explore the 'symbiotic - competitive' relationships between Microcystis and ARG-hosting bacteria under varied nutrient conditions. Addressing these knowledge gaps is crucial to understand the impacts of the algal aggregates on dynamics of waterborne antibiotic resistome, and underscores the need for effective control of Microcystis to curb the spread of antibiotic resistance. Constructed wetlands and photocatalysis represent advantageous strategies for halting the spread of ARGs from the perspective of Microcystis blooms, as they can effectively control Microcystis and MCs while maintaining the stability of aquatic ecosystem.202438802023
861310.9997Insights into the role of extracellular polymeric substances (EPS) in the spread of antibiotic resistance genes. Antibiotic resistance genes (ARG) are prevalent in aquatic environments. Discharge from wastewater treatment plants is an important point source of ARG release into the environment. It has been reported that biological treatment processes may enhance rather than remove ARG because of their presence in sludge. Attenuation of ARG in biotechnological processes has been studied in depth, showing that many microorganisms can secrete complex extracellular polymeric substances (EPS). These EPS can serve as multifunctional elements of microbial communities, involving aspects, such as protection, structure, recognition, adhesion, and physiology. These aspects can influence the interaction between microbial cells and extracellular ARG, as well as the uptake of extracellular ARG by microbial cells, thus changing the transformative capability of extracellular ARG. However, it remains unclear whether EPS can affect horizontal ARG transfer, which is one of the main processes of ARG dissemination. In light of this knowledge gap, this review provides insight into the role of EPS in the transmission of ARGs; furthermore, the mechanism of ARG spread is analyzed, and the molecular compositions and functional properties of EPS are summarized; also, how EPS influence ARG mitigation is addressed, and factors impacting how EPS facilitate ARG during wastewater treatment are summarized. This review provides comprehensive insights into the role of EPS in controlling the transport and fate of ARG during biodegradation processes at the mechanistic level.202438169168
963820.9996Response of microbial antibiotic resistance to pesticides: An emerging health threat. The spread of microbial antibiotic resistance has seriously threatened public health globally. Non-antibiotic stressors have significantly contributed to the evolution of bacterial antibiotic resistance. Although numerous studies have been conducted on the potential risk of pesticide pollution for bacterial antibiotic resistance, a systematic review of these concerns is still lacking. In the present study, we elaborate the mechanism underlying the effects of pesticides on bacterial antibiotic resistance acquisition as well as the propagation of antimicrobial resistance. Pesticide stress enhanced the acquisition of antibiotic resistance in bacteria via various mechanisms, including the activation of efflux pumps, inhibition of outer membrane pores for resistance to antibiotics, and gene mutation induction. Horizontal gene transfer is a major mechanism whereby pesticides influence the transmission of antibiotic resistance genes (ARGs) in bacteria. Pesticides promoted the conjugation transfer of ARGs by increasing cell membrane permeability and increased the proportion of bacterial mobile gene elements, which facilitate the spread of ARGs. This review can improve our understanding regarding the pesticide-induced generation and spread of ARGs and antibiotic resistant bacteria. Moreover, it can be applied to reduce the ecological risks of ARGs in the future.202235977623
749730.9996Microplastic biofilms promote the horizontal transfer of antibiotic resistance genes in estuarine environments. As emerging pollutants, microplastics can aggregate microorganisms on their surfaces and form biofilms, enriching antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Consequently, microplastic biofilms have become a focal point of research. Horizontal gene transfer is one of the primary mechanisms by which bacteria acquire antibiotic resistance, with much of the research focusing on suspended bacteria. However, microplastic biofilms, as hotspots for horizontal gene transfer, also merit significant investigation. This study primarily explored and compared the frequency of ARG conjugative transfer between suspended bacteria and microplastic biofilms. The results demonstrated that, compared to suspended bacteria, microplastic biofilms enhanced the frequency of ARG conjugative transfer by 7.2-19.6 times. Among them, biofilms on polyethylene microplastics showed the strongest promotion of conjugation. After the formation of microplastic biofilms, there was a significant increase in bacterial density within the biofilms, which raised the collision frequency of donor and recipient bacteria. Then microplastic biofilms facilitated the gene expression levels of outer membrane proteins, enhanced bacterial gene transfer capabilities, promoted the synthesis of conjugative pili, accelerated the formation of conjugative pairing systems, and elevated the expression levels of genes related to DNA replication and transfer systems, thereby enhancing the conjugative transfer of ARGs within microplastic biofilms. Among different types of microplastic biofilms, polyethylene biofilms exhibited the highest bacterial density, thus showing the highest frequency of ARG conjugation. This study highlights the risks associated with ARG conjugative transfer following the formation of microplastic biofilms and provides insights into the risks of microplastic and antibiotic resistance propagation in estuarine environments.202439368156
744240.9996Potential impacts of disinfection processes on elimination and deactivation of antibiotic resistance genes during water and wastewater treatment. Antibiotic resistance genes (ARGs), in association with antibiotic resistant bacteria (ARB), have been identified as widespread contaminants of treated drinking waters and wastewaters. As a consequence, concerns have been raised that ARB or ARG transport between aquatic compartments may enhance the spread of antibiotic resistance amongst non-resistant bacterial communities by means of horizontal gene transfer processes. Most often, discussion of horizontal gene transfer focuses on the probable role of conjugative plasmid or transposon exchange, which requires live ARB donor cells. Conventional water and wastewater disinfection processes generally provide highly effective means for mitigating the transport of live ARB; thereby minimizing risks of conjugative gene transfer. However, even if ARB present in a treated water are fully inactivated during a disinfection process, the possibility remains that intact remnants of DNA contained within the resulting cell debris could still confer resistance genotypes to downstream bacterial populations by means of natural transformation and/or transduction, which do not require live donor cells. Thus, a systematic evaluation of the capability of common disinfection technologies to ensure the destruction of bacterial DNA, in addition to pathogen inactivation, seems warranted. With that objective in mind, this review seeks to provide a concise introduction to the significance of ARB and ARG occurrence in environmental systems, coupled with a review of the role that commonly used water and wastewater disinfection processes may play in minimizing ARG transport and dissemination.201222572858
648350.9996Soil Component: A Potential Factor Affecting the Occurrence and Spread of Antibiotic Resistance Genes. In recent years, antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) in soil have become research hotspots in the fields of public health and environmental ecosystems, but the effects of soil types and soil components on the occurrence and spread of ARGs still lack systematic sorting and in-depth research. Firstly, investigational information about ARB and ARGs contamination of soil was described. Then, existing laboratory studies about the influence of the soil component on ARGs were summarized in the following aspects: the influence of soil types on the occurrence of ARGs during natural or human activities and the control of exogenously added soil components on ARGs from the macro perspectives, the effects of soil components on the HGT of ARGs in a pure bacterial system from the micro perspectives. Following that, the similarities in pathways by which soil components affect HGT were identified, and the potential mechanisms were discussed from the perspectives of intracellular responses, plasmid activity, quorum sensing, etc. In the future, related research on multi-component systems, multi-omics methods, and microbial communities should be carried out in order to further our understanding of the occurrence and spread of ARGs in soil.202336830244
643060.9996Plastic leachate exposure drives antibiotic resistance and virulence in marine bacterial communities. Plastic pollution is a serious global problem, with more than 12 million tonnes of plastic waste entering the oceans every year. Plastic debris can have considerable impacts on microbial community structure and functions in marine environments, and has been associated with an enrichment in pathogenic bacteria and antimicrobial resistance (AMR) genes. However, our understanding of these impacts is largely restricted to microbial assemblages on plastic surfaces. It is therefore unclear whether these effects are driven by the surface properties of plastics, providing an additional niche for certain microbes residing in biofilms, and/or chemicals leached from plastics, the effects of which could extend to surrounding planktonic bacteria. Here, we examine the effects of polyvinyl chloride (PVC) plastic leachate exposure on the relative abundance of genes associated with bacterial pathogenicity and AMR within a seawater microcosm community. We show that PVC leachate, in the absence of plastic surfaces, drives an enrichment in AMR and virulence genes. In particular, leachate exposure significantly enriches AMR genes that confer multidrug, aminoglycoside and peptide antibiotic resistance. Additionally, enrichment of genes involved in the extracellular secretion of virulence proteins was observed among pathogens of marine organisms. This study provides the first evidence that chemicals leached from plastic particles alone can enrich genes related to microbial pathogenesis within a bacterial community, expanding our knowledge of the environmental impacts of plastic pollution with potential consequences for human and ecosystem health.202337019264
648270.9996Potential risks of antibiotic resistant bacteria and genes in bioremediation of petroleum hydrocarbon contaminated soils. Bioremediation represents a sustainable approach to remediating petroleum hydrocarbon contaminated soils. One aspect of sustainability includes the sourcing of nutrients used to stimulate hydrocarbon-degrading microbial populations. Organic nutrients such as animal manure and sewage sludge may be perceived as more sustainable than conventional inorganic fertilizers. However, organic nutrients often contain antibiotic residues and resistant bacteria (along with resistance genes and mobile genetic elements). This is further exacerbated since antibiotic resistant bacteria may become more abundant in contaminated soils due to co-selection pressures from pollutants such as metals and hydrocarbons. We review the issues surrounding bioremediation of petroleum-hydrocarbon contaminated soils, as an example, and consider the potential human-health risks from antibiotic resistant bacteria. While awareness is coming to light, the relationship between contaminated land and antibiotic resistance remains largely under-explored. The risk of horizontal gene transfer between soil microorganisms, commensal bacteria and/or human pathogens needs to be further elucidated, and the environmental triggers for gene transfer need to be better understood. Findings of antibiotic resistance from animal manures are emerging, but even fewer bioremediation studies using sewage sludge have made any reference to antibiotic resistance. Resistance mechanisms, including those to antibiotics, have been considered by some authors to be a positive trait associated with resilience in strains intended for bioremediation. Nevertheless, recognition of the potential risks associated with antibiotic resistant bacteria and genes in contaminated soils appears to be increasing and requires further investigation. Careful selection of bacterial candidates for bioremediation possessing minimal antibiotic resistance as well as pre-treatment of organic wastes to reduce selective pressures (e.g., antibiotic residues) are suggested to prevent environmental contamination with antibiotic-resistant bacteria and genes.202032236187
964280.9996Towards the fate of antibiotics and the development of related resistance genes in stream biofilms. Antibiotics are ubiquitously found in natural surface waters and cause great harm to aquatic organisms. Stream biofilm is a complex and active community composed of algae, bacteria, fungi and other microorganisms, which mainly adheres to solid substances such as rocks and sediments. The durability and diverse structural and metabolic characteristics of biofilms make them a representative of microbial life in aquatic micrecosystems and can reflect major ecosystem processes. Microorganisms and extracellular polymeric substances in biofilms can adsorb and actively accumulate antibiotics. Therefore, biofilms are excellent biological indicators for detecting antibiotic in polluted aquatic environments, but the biotransformation potential of stream biofilms for antibiotics has not been fully explored in the aquatic environment. The characteristics of stream biofilm, such as high abundance and activity of bacterial community, wide contact area with pollutants, etc., which increases the opportunity of biotransformation of antibiotics in biofilm and contribute to bioremediation to improve ecosystem health. Recent studies have demonstrated that both exposure to high and sub-minimum inhibitory concentrations of antibiotics may drive the development of antibiotic resistance genes (ARGs) in natural stream biofilms, which are susceptible to the effects of antibiotic residues, microbial communities and mobile genetic elements, etc. On the basis of peer-reviewed papers, this review explores the distribution behavior of antibiotics in stream biofilms and the contribution of biofilms to the acquisition and spread of antibiotic resistance. Considering that antibiotics and ARGs alter the structure and ecological functions of natural microbial communities and pose a threat to river organisms and human health, our research findings provide comprehensive insights into the migration, transformation, and bioavailability of antibiotics in biofilms.202337454845
963490.9996New perspectives on bacterial chlorine resistance: Phages encoding chlorine resistance genes improve bacterial adaptation. Bacterial resistance to chlorine disinfectant reduces its effectiveness in killing pathogenic bacteria and poses a severe threat to environmental and health safety. The interaction between bacteria and phages is the most frequent biological activity in Earth's biosphere, but little is known about what role and mechanism phages play in the resistance of bacterial communities to chlorine disinfectants. Here, we investigated the changes in the abundance, activity and function of the bacterial-phage community under the effect of chlorine disinfectants in a 92-day running anaerobic-anoxic-oxic system, using metagenomics and metatranscriptomics sequencing. We found that transcriptional activities of both bacteria and phage are highly sensitive to chlorine disinfectants, although their relative abundance was not obviously altered. The increase in both phage diversity and the ratio of temperate to lytic phages' average activity indicated phages, especially temperate, could play a crucial role in the response to chlorine disinfectants. Interestingly, the phages that carry chlorine resistance genes (CRGs) were the drivers of the phage and microbial community when chlorine disinfectants were present, but they followed the dynamics of community in the absence of chlorine disinfectants. Based on the association bipartite network, we further found that phages directly mediated the horizontal transfer of CRGs among bacteria, facilitating the spread of CRGs in the bacterial community. Moreover, the 4 CRGs related to cell wall repair, redox balance regulation, and efflux pumps that were carried by the phages but lacking in the hosts suggest the potential compensatory effects of the phage for the chlorine resistance of their hosts. Our findings reveal the important role of phages in improving the resistance of bacterial communities to chlorine disinfectants, providing a new perspective on the co-evolution of phages and bacteria to adapt to environments.202540245807
8565100.9996Deciphering the transfers of antibiotic resistance genes under antibiotic exposure conditions: Driven by functional modules and bacterial community. Antibiotics can exert selective pressures on sludge as well as affect the emergence and spread of antibiotic resistance genes (ARGs). However, the underlying mechanisms of ARGs transfers are still controversial and not fully understood in sludge system. In present study, two anaerobic sequence batch reactors (ASBR) were constructed to investigate the development of ARGs exposed to two sulfonamide antibiotics (SMs, sulfadiazine SDZ and sulfamethoxazole SMX) with increasing concentrations. The abundance of corresponding ARGs and total ARGs obviously increased with presence of SMs. Functional analyses indicated that oxidative stress response, signal transduction and type IV secretion systems were triggered by SMs, which would promote ARGs transfers. Network analysis revealed 18 genera were possible hosts of ARGs, and their abundances increased with SMs. Partial least-squares path modeling suggested functional modules directly influenced mobile genetic elements (MGEs) as well as the ARGs might be driven by both functional modules and bacteria community, while bacteria community composition played a more key role. Sludge with refractory antibiotics (SDZ) may stimulate the relevant functions and shift the microbial composition to a greater extent, causing more ARGs to emerge and spread. The mechanisms of ARGs transfers are revealed from the perspective of functional modules and bacterial community in sludge system for the first time, and it could provide beneficial directions, such as oxidative stress reduction, cellular communication control, bacterial composition directional regulation, for ARGs spread controlling in the future.202134563930
7486110.9996Body size: A hidden trait of the organisms that influences the distribution of antibiotic resistance genes in soil. Body size is a key life-history trait of organisms, which has important ecological functions. However, the relationship between soil antibiotic resistance gene (ARG) distribution and organisms' body size has not been systematically reported so far. Herein, the impact of organic fertilizer on the soil ARGs and organisms (bacteria, fungi, and nematode) at the aggregate level was analyzed. The results showed that the smaller the soil aggregate size, the greater the abundance of ARGs, and the larger the body size of bacteria and nematodes. Further analysis revealed significant positive correlations of ARG abundance with the body sizes of bacteria, fungi, and nematodes, respectively. Additionally, the structural equation model demonstrated that changes in soil fertility mainly regulate the ARG abundance by affecting bacterial body size. The random forest model revealed that total phosphorus was the primary soil fertility factor influencing the body size of organisms. Therefore, these findings proposed that excessive application of phosphate fertilizers could increase the risk of soil ARG transmission by increasing the body size of soil organisms. This study highlights the significance of organisms' body size in determining the distribution of soil ARGs and proposes a new disadvantage of excessive fertilization from the perspective of ARGs.202438696961
6458120.9996Overview of Direct and Indirect Effects of Antibiotics on Terrestrial Organisms. Antibiotics (ABs) have made it possible to treat bacterial infections, which were in the past untreatable and consequently fatal. Regrettably, their use and abuse among humans and livestock led to antibiotic resistance, which has made them ineffective in many cases. The spread of antibiotic resistance genes (ARGs) and bacteria is not limited to nosocomial environments, but also involves water and soil ecosystems. The environmental presence of ABs and ARGs is a hot topic, and their direct and indirect effects, are still not well known or clarified. A particular concern is the presence of antibiotics in agroecosystems due to the application of agro-zootechnical waste (e.g., manure and biosolids), which can introduce antibiotic residues and ARGs to soils. This review provides an insight of recent findings of AB direct and indirect effects on terrestrial organisms, focusing on plant and invertebrates. Possible changing in viability and organism growth, AB bioaccumulation, and shifts in associated microbiome composition are reported. Oxidative stress responses of plants (such as reactive oxygen species production) to antibiotics are also described.202337760767
6419130.9996Can microplastics and disinfectant resistance genes pose conceivable threats to water disinfection process? Microplastic pollution in the environment has aroused widespread concerns, however, the potential environmental risks caused by excessive use of disinfectants are still unknown. Disinfectants with doses below the threshold can enhance the communication of resistance genes in pathogenic microorganisms, promoting the development and spread of antimicrobial activity. Problematically, the intensification of microplastic pollution and the increase of disinfectant consumption will become a key driving force for the growth of disinfectant resistance bacteria (DRB) and disinfectant resistance genes (DRGs) in the environment. Disinfection plays a crucial role in ensuring water safety, however, the presence of microplastics and DRGs seriously disturb the water disinfection process. Microplastics can reduce the concentration of disinfectant in the local environment around microorganisms and improve their tolerance. Microorganisms can improve their resistance to disinfectants or generate resistance genes via phenotypic adaptation, gene mutations, and horizontal gene transfer. However, very limited information is available on the impact of DRB and DRGs on disinfection process. In this paper, the contribution of microplastics to the migration and transmission of DRGs was analyzed. The challenges posed by the presence of microplastics and DRGs on conventional disinfection were thoroughly discussed. The knowledge gaps faced by relevant current research and further research priorities have been proposed in order to provide a scientific basis in the future.202337730038
7485140.9996Fungal networks serve as novel ecological routes for enrichment and dissemination of antibiotic resistance genes as exhibited by microcosm experiments. Antibiotic resistance genes (ARGs) in the environment and their subsequent acquisition by clinically important microorganisms are a serious concern. However, the spread of environmental ARGs remain largely unknown. We report, for the first time, the involvement of soil fungi in the distribution of bacteria with ARGs via soil microcosms. qPCR assay detected unique ARGs specifically found in the mycosphere of different fungi. Interestingly, the taxonomically and ecologically different fungi exerted different selection pressures on ARGs originating from the same source. Test fungi supported different antibiotic resistance bacteria enriched in the mycosphere and even transported to distant places. The relative abundance of the tnpA gene decreased, for manure, along mycelial networks of all fungi. While the fungal strain NFC-5 enriched the intI1 gene more, opposite to two other fungi at the migration front compared with the inoculation point for both sources. Such data indicate the differential effect of different fungi to facilitate horizontal gene transfer potential under fungal selection pressure. Our study provides the evidence that fungi can contribute ARGs, host bacterial diversity and abundance, and such interactive microbial consortia have the potential to disseminate the resistance determinants from one place to another, thus increasing the ARGs exposure risk to humans.201729133838
6431150.9996The dynamics and transmission of antibiotic resistance associated with plant microbiomes. Antibiotic resistance genes (ARGs) have been widely found and studied in soil and water environments. However, the propagation of ARGs in plant microbiomes has attracted insufficient attention. Plant microbiomes, especially the rhizosphere microorganisms, are closely connected with water, soil, and air, which allows ARGs to spread widely in ecosystems and pose a threat to human health after entering the human body with bacteria. Therefore, it is necessary to deeply understand and explore the dynamics and the transmission of ARGs in rhizosphere microorganisms and endophytes of plants. In this review, the transmission and influencing factors of ARGs in the microorganisms associated with plants, especially the influence of root exudates on plant microbiomes, are analyzed. Notably, the role of intrinsic genes of plants in determining root exudates and their potential effects on ARGs are proposed and analyzed. The important role of phyllosphere microorganisms and endophytes in the transmission of ARGs and co-resistance of antibiotics and other substances are also emphasized. The proliferation and transmission of ARGs associated with plant microbiomes addressed in this review is conducive to revealing the fate of ARGs in plant microorganisms and alleviating ARG pollution.202337257204
6455160.9996Bacteriophages: Underestimated vehicles of antibiotic resistance genes in the soil. Bacteriophages (phages), the most abundant biological entities on Earth, have a significant effect on the composition and dynamics of microbial communities, biogeochemical cycles of global ecosystems, and bacterial evolution. A variety of antibiotic resistance genes (ARGs) have been identified in phage genomes in different soil samples. Phages can mediate the transfer of ARGs between bacteria via transduction. Recent studies have suggested that anthropogenic activities promote phage-mediated horizontal gene transfer events. Therefore, the role of phages in the dissemination of ARGs, which are a potential threat to human health, may be underestimated. However, the contribution of phages to the transfer of ARGs is still poorly understood. Considering the growing and wide concerns of antibiotic resistance, phages should be considered a research focus in the mobile resistome. This review aimed to provide an overview of phages as vehicles of ARGs in soil. Here, we summarized the current knowledge on the diversity and abundance of ARGs in soilborne phages and analyzed the contribution of phages to the horizontal transfer of ARGs. Finally, research deficiencies and future perspectives were discussed. This study provides a reference for preventing and controlling ARG pollution in agricultural systems.202235992716
6409170.9996Bacterial perspectives on the dissemination of antibiotic resistance genes in domestic wastewater bio-treatment systems: beneficiary to victim. Domestic wastes, ranging from sewage and sludge to municipal solid waste, are usually treated in bioprocessing systems. These systems are regarded as main conduits for the elevated levels of antibiotic resistance genes (ARGs) observed in the environment. This paper mainly reviews recent studies on the occurrence and dynamics of ARGs in wastewater bio-treatment systems and discusses the ins and outs of ARG dissemination from the perspective of the microbial community. Our analysis shows that concentration of antibiotics through adsorption to microbial aggregates triggers the bacteria to acquire ARGs, which can be facilitated by the presence of mobile genetic elements. Notably, the acquisition and flow of ARGs during the rapid dissemination process is directed towards and for the best interests of the microbial community as a whole, and is influenced by surrounding nutrient levels, toxicant types, and sensitivities of the species in the prevailing antibiotic-stressed conditions. Furthermore, our review argues that predation of ARG-carrying bacteria by bacteriophages does periodically enhance the accessibility of ARGs to bacteria, which indirectly facilitates the recruitment of ARGs into environmental microbial communities.201829198067
6406180.9996The Environmental Lifecycle of Antibiotics and Resistance Genes: Transmission Mechanisms, Challenges, and Control Strategies. Antibiotics are widely used in modern medicine. However, as global antibiotic consumption rises, environmental contamination with antibiotics and antibiotic resistance genes (ARGs) is becoming a serious concern. The impact of antibiotic use on human health is now under scrutiny, particularly regarding the emergence of antibiotic-resistant bacteria (ARB) in the environment. This has heightened interest in technologies for treating ARGs, highlighting the need for effective solutions. This review traces the life cycle of ARB and ARGs driven by human activity, revealing pathways from antibiotic use to human infection. We address the mechanisms enabling resistance in ARB during this process. Beyond intrinsic resistance, the primary cause of ARB resistance is the horizontal gene transfer (HGT) of ARGs. These genes exploit mobile genetic elements (MGEs) to spread via conjugation, transformation, transduction, and outer membrane vesicles (OMVs). Currently, biological wastewater treatment is the primary pollution control method due to its cost-effectiveness. However, these biological processes can promote ARG propagation, significantly amplifying the environmental threat posed by antibiotics. This review also summarizes key mechanisms in the biological treatment of antibiotics and evaluates risks associated with major ARB/ARG removal processes. Our aim is to enhance understanding of ARB risks, their pathways and mechanisms in biotreatment, and potential biomedical applications for pollution control.202541011444
9640190.9996Effects of microplastic concentration, composition, and size on Escherichia coli biofilm-associated antimicrobial resistance. Microplastics (MPs) have emerged as a significant environmental pollutant with profound implications for public health, particularly as substrates to facilitate bacterial antimicrobial resistance (AMR). Recently, studies have shown that MPs may accommodate biofilm communities, chemical contaminants, and genetic material containing AMR genes. This study investigated the effects of MP concentration, composition, and size on the development of multidrug resistance in Escherichia coli. Specifically, we exposed E. coli to varying concentrations of different MP types, including polyethylene, polystyrene, and polypropylene, across a range of sizes (3-10, 10-50, and 500 µm). Results indicated that the biofilm cells attached to MPs had elevated multidrug resistance (in E. coli. Notably, MPs exhibited a higher propensity for facilitating biofilm and resistance than control substrates such as glass, likely due to their hydrophobicity, greater adsorption capacities, and surface chemistries. Notably, we found that the bacteria passaged with MPs formed stronger biofilms once the MPs were removed, which was associated with changes in motility. Thus, MPs select cells that are better at forming biofilms, which can lead to biofilm-associated AMR and recalcitrant infections in the environment and healthcare setting. Our study highlights the importance of developing effective strategies to address the challenges posed by MPs. IMPORTANCE: Antimicrobial resistance (AMR) is one of the world's most pressing global health crises. With the pipeline of antibiotics running dry, it is imperative that mitigation strategies understand the mechanisms that drive the genesis of AMR. One emerging dimension of AMR is the environment. This study highlights the relationship between a widespread environmental pollutant, microplastics (MPs), and the rise of drug-resistant bacteria. While it is known that MPs facilitate resistance through several modes (biofilm formation, plastic adsorption rates, etc.), this study fills the knowledge gap on how different types of MPs are contributing to AMR.202540067049