Unveiling the kinetics and mechanism of carbonate radicals in antibiotic resistance dissemination. - Related Documents




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849001.0000Unveiling the kinetics and mechanism of carbonate radicals in antibiotic resistance dissemination. The escalating contamination of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in aquatic systems has driven extensive investigations into their interactions with reactive intermediates. However, the reaction kinetics and mechanisms underlying the degradation of ARB and ARGs by CO(3)(•-) remain unelucidated. This study quantifies the reaction rate constants between CO(3)(•-) and ARB, ARGs, and critical biomolecules including extracellular polymeric substances, phospholipids, amino acids, and deoxynucleotides. Results demonstrate negligible CO(3)(•-) reactivity with phospholipids and amino acids (< 10(5) M(-1)·s(-1)), yet remarkably high reaction rates (∼10(7) M(-1)·s(-1)) with ARB, ARGs and deoxynucleotides. Mechanistic studies demonstrate that CO(3)(•-) enhances membrane fluidity by attenuating inter-lipid interactions and reducing lipid ordering (Δη = -60.44 %), thereby driving transmembrane co-transport with HCO(3)⁻. Notably, CO(3)(•-) exhibits an extended reaction radius (1.30-2.31 μm, far exceeding typical membrane-targeting radicals) and exploits its low membrane affinity to achieve deep cellular penetration. Within cells, it selectively oxidizes biomolecules, primarily via deoxyguanosine modification, inducing ARGs damage and systemic biomolecular dysregulation. Integrated transcriptomic and metabolomic analyses confirm these genotoxic impacts, revealing perturbations at transcriptional regulation and metabolic pathway levels. These results establish CO(3)(•-) as a potential key agent in suppressing antibiotic resistance dissemination, resolving a critical knowledge gap in environmental radical-ARB/ARGs interactions.202541101271
678310.9995Mechanism of earthworm coelomic fluid inhibits multidrug-resistant bacteria and blocks resistance transmission. Antibiotic resistance is a growing global health crisis, especially the spread of multi-drug resistance. In this study, the inhibitory effects of earthworm coelomic fluid (ECF) on multidrug-resistant bacteria (MRB) were investigated during employing vermicomposting to treat excess sludge generated from wastewater treatment. The results demonstrated that the ECF was able to inhibit, even completely decompose the MRB. Notably, when the ECF concentration reached 1.0 mg/mL, the intracellular reactive oxygen species (ROS) level increased by 46.7 %, while cell viability decreased by 55.2 % compared to the control, demonstrating that ECF exerts strong antibacterial activity by inducing oxidative stress and disrupting cellular homeostasis. Furthermore, ECF effectively degraded the DNA of MRB, with removal rates of aphA, KanR, and tetA reaching 51.8 %, 42.3 %, and 35.0 %, respectively, indicating its ability to eliminate resistance genes and hinder their potential transfer. Additionally, the upregulation of genes involved in signaling, DNA replication and repair, and energy metabolism pathways suggests a systemic stress response in MRB, further supporting the broad-spectrum inhibitory effects of ECF on bacterial viability and resistance maintenance. Taken together, these findings may open a door to naturally and ecologically combat antibiotic resistance in pollutants control in wastewater treatment.202540706790
850620.9995Extracellular Polymeric Substances Acting as a Permeable Barrier Hinder the Lateral Transfer of Antibiotic Resistance Genes. Antibiotic resistance genes (ARGs) in bacteria are emerging contaminants as their proliferation in the environment poses significant threats to human health. It is well recognized that extracellular polymeric substances (EPS) can protect microorganisms against stress or damage from exogenous contaminants. However, it is not clear whether EPS could affect the lateral transfer of ARGs into bacteria, which is one of the major processes for the dissemination of ARGs. This study investigated the lateral transfer of ARGs carried by plasmids (pUC19, pHSG298, and pHSG396) into competent Escherichia coli cells with and without EPS. Transformant numbers and transformation efficiency for E. coli without EPS were up to 29 times of those with EPS at pH 7.0 in an aqueous system. The EPS removal further increased cell permeability in addition to the enhanced cell permeability by Ca(2+), which could be responsible for the enhanced lateral transfer of ARGs. The fluorescence quenching experiments showed that EPS could strongly bind to plasmid DNA in the presence of Ca(2+) and the binding strength (LogK (A) = 10.65-15.80 L mol(-1)) between EPS and plasmids was positively correlated with the enhancement percentage of transformation efficiency resulting from the EPS removal. X-ray photoelectron spectroscopy (XPS) analyses and model computation further showed that Ca(2+) could electrostatically bind with EPS mainly through the carboxyl group, hydroxyl group, and RC-O-CR in glucoside, thus bridging the plasmid and EPS. As a result, the binding of plasmids with EPS hindered the lateral transfer of plasmid-borne ARGs. This study improved our understanding on the function of EPS in controlling the fate and transport of ARGs on the molecular and cellular scales.201931057498
852830.9995Non-negligible effects of sunlight irradiation on generation of VBNC-state antibiotic resistant bacteria in natural water. The viable but non-culturable (VBNC) state antibiotic resistant bacteria (ARB) poses significant environmental risk. The mechanism by which simulated sunlight irradiation induces ARB to enter the VBNC state remains unclear. This study systematically explored the photochemical generation mechanism of VBNC-ARB in natural water. Ampicillin-resistant Escherichia coli (AR E. coli) was selected as a representative ARB. The results showed that AR E. coli lost cultivability under sunlight with 91.1 % of AR E. coli entering the VBNC state. Suwannee River fulvic acid (SRFA) slightly enhanced this effect and can induce 95.9 % of AR E. coli into the VBNC state. Under sunlight exposure, oxidative stress and the toxin-antitoxin (TA) system in AR E. coli were identified as key factors in inducing the VBNC state. This process was accompanied by a deterioration in cell membrane fluidity, upregulation of cell wall and outer membrane-related genes, and toxin-mediated inhibition of DNA replication. Importantly, AR E. coli retained intact antibiotic resistance genes (ARGs) and could reactivate these genes in the dark, with SRFA promoting this recovery. Therefore, VBNC-ARB remains antibiotic resistance and increases virulence expression, consequently increasing human health risks. These findings underscore the need for effective strategies to manage VBNC-ARB in environmental systems.202540280065
850240.9995Simultaneously disinfection of amoebae, endosymbiotic bacteria, and resistance genes using a novel two-electron water oxidation strategy. Amoebae, which serve as important vectors for various pathogenic bacteria, are ubiquitous in natural and artificial water systems. Their robust survival capabilities and protective characteristics render conventional disinfection methods largely ineffective. Moreover, amoeba cells provide an ideal environment for the replication and transfer of antibiotic resistance genes, posing a significant threat to human health and safety. In this study, an in-situ activation system for electrocatalytic water oxidation was developed. This system effectively inactivates amoeba spores and their intracellular symbiotic bacteria while simultaneously reducing the abundance of resistance genes through the generation of hydroxyl radicals (•OH) and carbonate free radicals (•CO(3)(-)). The results demonstrated a 99.9 % inactivation rate for amoeba spores and a 99.999 % inactivation rate for intracellular bacteria. In addition, the prevalence of resistant genes in bacteria within amoebae, specifically including sul1 (sulfonamide resistance), tetA (tetracycline resistance), blaFOX (cefoxitin resistance), arsB (arsenic resistance), czcA (cadmium resistance), and copA (copper resistance), was significantly reduced by approximately 16 %-62.6 %. Therefore, this study introduces a new technology capable of simultaneously treating amoeba spores, intracellular bacteria, and resistance genes, which holds significant importance for reducing the spread of resistant genes and enhancing public health safety.202540449332
850150.9994Mechanistic insight of simultaneous removal of tetracycline and its related antibiotic resistance bacteria and genes by ferrate(VI). The emergence of antibiotics and their corresponding antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have posed great challenges to the public health. The paper demonstrates the removal of co-existing tetracycline (TC), its resistant Escherichia coli (E. coli), and ARGs (tetA and tetR) in a mixed system by applying ferrate(VI) (Fe(VI)O(4)(2-), Fe(VI)) at pH 7.0. TC was efficiently degraded by Fe(VI), and the rapid inactivation of the resistant E. coli was found with the complete loss of culturability. The results of flow cytometry suggested that the damage of membrane integrity and respiratory activity were highly correlated with the Fe(VI) dosages. Moreover, high-dose Fe(VI) eliminates 6 log(10) viable but non-culturable (VBNC) cells and even breaks the cells into fragments. ARGs in extracellular form (e-ARGs) exhibited a high sensitivity of 4.44 log(10) removal to Fe(VI). Comparatively, no removal of intracellular ARGs (i-ARGs) was observed due to the multi-protection of cellular structure and rapid decay of Fe(VI). The oxidized products of TC were assessed to be less toxic than the parent compound. Overall, this study demonstrated the superior efficiency and great promise of Fe(VI) on simultaneous removal of antibiotics and their related ARB and ARGs in water.202133984704
851260.9994Dissolved oxygen facilitates efficiency of chlorine disinfection for antibiotic resistance. Controlling the dissemination of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) is a global concern. While commonly used chlorine disinfectants can damage or even kill ARB, dissolved oxygen (DO) may affect the formation of reactive chlorine species. This leads to the hypothesis that DO may play roles in mediating the effectiveness of chlorine disinfection for antibiotic resistance. To this end, this study investigated the impacts of DO on the efficiency of chlorine disinfection for antibiotic resistance. The results revealed that DO could increase the inactivation efficiency of ARB under chloramine and free chlorine exposure at practically relevant concentrations. Reactive species induced by DO, including H(2)O(2), O(2)(-), and OH, inactivated ARB strains by triggering oxidative stress response and cell membrane damage. In addition, the removal efficiency of extracellular ARGs (i.e. tetA and bla(TEM)) was enhanced with increasing dosage of free chlorine or chloramine under aerobic conditions. DO facilitated the fragmentation of plasmids, contributing to the degradation of extracellular ARGs under exposure to chlorine disinfectants. The findings suggested that DO facilitates disinfection efficiency for antibiotic resistance in water treatment systems.202438750753
881970.9994Responses of Bacillus sp. under Cu(II) stress in relation to extracellular polymeric substances and functional gene expression level. The production and composition of extracellular polymeric substances (EPS), as well as the EPS-related functional resistance genes and metabolic levels of Bacillus sp. under Cu(II) stress, were investigated. EPS production increased by 2.73 ± 0.29 times compared to the control when the strain was treated with 30 mg L(-1) Cu(II). Specifically, the polysaccharide (PS) content in EPS increased by 2.26 ± 0.28 g CDW(-1) and the PN/PS (protein/polysaccharide) ratio value increased by 3.18 ± 0.33 times under 30 mg L(-1) Cu(II) compared to the control. The increased EPS secretion and higher PN/PS ratio in EPS strengthened the cells' ability to resist the toxic effect of Cu(II). Differential expression of functional genes under Cu(II) stress was revealed by Gene Ontology pathway enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. The enriched genes were most obviously upregulated in the UMP biosynthesis pathway, the pyrimidine metabolism pathway, and the TCS metabolism pathway. This indicates an enhancement of EPS regulation-related metabolic levels and their role as a defense mechanism for cells to adapt to Cu(II) stress. Additionally, seven copper resistance genes were upregulated while three were downregulated. The upregulated genes were related to the heavy metal resistance, while downregulated genes were related to cell differentiation, indicating that the strain had initiated an obvious resistance to Cu(II) despite its severe cell toxicity. These results provided a basis for promoting EPS-regulated associated functional genes and the application of gene-regulated bacteria in heavy metal-containing wastewater treatment.202337195605
677780.9994Unveiling the role of uranium in enhancing the transformation of antibiotic resistance genes. Transformation represents one of the most important pathways for the horizontal transfer of antibiotic resistance genes (ARGs), which enables competent bacteria to acquire extracellular ARGs from the surrounding environment. Both heavy metals and irradiation have been demonstrated to influence the bacterial transformation process. However, the impact of ubiquitously occurring radioactive heavy metals on the transformation of ARGs remains largely unknown. Here, we showed that a representative radioactive nuclide, uranium (U), at environmental concentrations (0.005-5 mg/L), improved the transformation frequency of resistant plasmid pUC19 into Escherichia coli by 0.10-0.85-fold in a concentration-dependent manner. The enhanced ARGs transformation ability under U stress was demonstrated to be associated with reactive oxygen species (ROS) overproduction, membrane damage, and up-regulation of genes related to DNA uptake and recombination. Membrane permeability and ROS production were the predominant direct and indirect factors affecting transformation ability, respectively. Our findings provide valuable insight into the underlying mechanisms of the impacts of U on the ARGs transformation process and highlight concerns about the exacerbated spread of ARGs in radioactive heavy metal-contaminated ecosystems, especially in areas with nuclear activity or accidents.202439208634
673690.9994Biotic pathways of reciprocal responses between antibiotic resistance genes and inorganic nitrogen cycling genes in amoxicillin-stressed compost ecosystems. This study explored the transformation of inorganic nitrogen, the expression levels of antibiotic resistance genes (ARGs), and the regulatory mechanisms of key species on ARGs and inorganic nitrogen cycling genes (INCGs) under different levels of amoxicillin (AMX) stress. High level of AMX inhibited the accumulation of NH(4)(+)-N, which increased by 531 % relative to the initial. Moreover, AMX to some extent increased the levels of nirS and nirK, which could potentially result in nitrogen loss and the accumulation of NO(2)(-). Actinobacteria might serve as potential hosts for ARGs during sludge composting. This stress induced a complex response between INCGs and ARGs more complex due to key species. Under high-level AMX pressure, most species associated with ARGs likely derived from nitrogen cycling functional species. To conclude, high levels of AMX stress might lead to nitrogen cycling imbalance and the dissemination of antibiotic resistance genes in composting systems.202438387840
8504100.9994Chloroxylenol at environmental concentrations can promote conjugative transfer of antibiotic resistance genes by multiple mechanisms. The intergeneric conjugative transfer of antibiotic resistance genes (ARGs) is recognized as an important way to the dissemination of antibiotic resistance. However, it is unknown whether the extensive use of chloroxylenol (para-chloro-meta-xylenol, PCMX) in many pharmaceutical personal care products will lead to the spread of ARGs. In this study, the abilities and mechanisms of PCMX to accelerate the intergeneric conjugative transfer were investigated. Results showed that exposure of bacteria to environmental concentrations of PCMX (0.20-1.00 mg/L) can significantly stimulate the increase of conjugative transfer by 8.45-9.51 fold. The phenotypic experiments and genome-wide RNA sequencing revealed that 0.02-5.00 mg/L PCMX exposure could increase the content of alkaline phosphatase and malondialdehyde, which are characteristic products of cell wall and membrane damage. In addition, PCMX could lead to excessive production of reactive oxygen species (ROS) by 1.26-2.00 times, the superoxide dismutase and catalase produced by bacteria in response to oxidative stress were not enough to neutralize the damage of ROS, thus promoting the conjugative transfer. Gene Ontology enrichment analysis indicated that cell membrane permeability, pili, some chemical compounds transport and energy metabolism affected conjugative transfer. This study deepened the understanding of PCMX in promoting propagation of ARGs, and provided new perspectives for use and treatment of personal care products.202234774958
8540110.9994Metagenomic insights into the mechanism for the rapid enrichment and high stability of Candidatus Brocadia facilitated by Fe(Ⅲ). The rapid enrichment of anammox bacteria and its fragile resistance to adverse environment are the critical problems facing of anammox processes. As an abundant component in anammox bacteria, iron has been proved to promote the activity and growth of anammox bacteria in the mature anammox systems, but the functional and metabolic profiles in Fe(III) enhanced emerging anammox systems have not been evaluated. Results indicated that the relative abundance of functional genes involved in oxidative phosphorylation, nitrogen metabolism, cofactors synthesis, and extracellular polymers synthesis pathways was significantly promoted in the system added with 5 mg/L Fe(III) (R5). These enhanced pathways were crucial to energy generation, nitrogen removal, cell activity and proliferation, and microbial self-defense, thereby accelerating the enrichment of anammox bacteria Ca. Brocadia and facilitating their resistance to adverse environments. Microbial community analysis showed that the proportion of Ca. Brocadia in R5 also increased to 64.42 %. Hence, R5 could adapt rapidly to the increased nitrogen loading rate and increase the nitrogen removal rate by 108 % compared to the system without Fe(III) addition. However, the addition of 10 and 20 mg/L Fe(III) showed inhibitory effects on the growth and activity of anammox bacteria, which exhibited the lower relative abundance of Ca. Brocadia and unstable or even collapsed nitrogen removal performance. This study not only clarified the concentration range of Fe(III) that promoted and inhibited the enrichment of anammox bacteria, but also deepened our understanding of the functional and metabolic mechanisms underlying enhanced enrichment of anammox bacteria by Fe(III), providing a potential strategy to hasten the start-up of anammox from conventional activated sludge.202438309072
8503120.9994Dual-pathway inhibition of antibiotic resistance genes by ferrate (Fe(VI)): Oxidative inactivation and genetic mobility impairment in anaerobically digested sludge. Antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB) are emerging environmental contaminants that threaten public health, highlighting the urgent need for effective control strategies. Ferrate (Fe(VI)), a strong and eco-friendly oxidant, shows great potential for this purpose. This study systematically evaluated the efficacy of Fe(VI) in mitigating ARGs and ARB in anaerobically digested sludge, with a particular focus on elucidating the underlying mechanisms by which Fe(VI) effects ARGs dissemination through both vertical gene transfer (VGT) and horizontal gene transfer (HGT). Result shows that Fe(VI) doses of 20 and 60 mg/g-TS reduce ARGs by 9.75 % and 19.12 %, respectively, while inactivating up to 24.7 % of ARB at the higher dose. Pathogenic ARB, such as Escherichia coli and Shigella sonnei, are preferentially removed, with abundances decrease by 63.7 % and 28.0 %. Mechanistically, the structural disruption of bacterial cells caused by Fe(VI) in anaerobically digested sludge, as indicated by a 29 % reduction in extracellular polymeric substances and a 23.7 % increase in cell membrane permeability. Subsequently, a marked release of intracellular ARGs into the extracellular environment is also observed, where they are likely subjected to degradation by Fe(VI). This oxidative killing accounts for the observed ARB decrease, thereby limiting the VGT of ARGs. In addition, Fe(VI) impairs the HGT of ARGs by diminishing their mobility potential, reflected in the reduced co-occurence with mobile genetic elements. Meanwhile, sludge bacterial competence for DNA uptake and recombination is markedly reduced, as evidenced by a 9.8 % decline in the abundance of related functional genes. These findings demonstrate that Fe(VI) effectively inhibits the dissemination of ARGs by targeting both primary transmission pathways. It suppresses VGT, thereby reducing the inheritance of ARB within populations, and limits HGT, curbing the spread of mobile ARGs among competent species. By disrupting these two critical routes, Fe(VI) shows strong potential as an effective strategy for mitigating ARGs propagation in sludge systems.202541138327
8981130.9994Response mechanisms of different antibiotic-resistant bacteria with different resistance action targets to the stress from photocatalytic oxidation. The stress response of antibiotic-resistant bacteria (ARB) and the spread of antibiotic resistance genes (ARGs) pose a serious threat to the aquatic environment and human beings. This study mainly explored the effect of the heterogeneous photocatalytic oxidation (UVA-TiO(2) system) on the stress response mechanism of ARB with different antibiotic resistance action targets, including the cell wall, proteins, DNA, RNA, folate and the cell membrane. Results indicate that the stress response mechanism of tetracycline- and sulfamethoxazole-resistant E. coli DH5α, which targets the synthesis of protein and folate, could rapidly induce global regulators by the overexpression of relative antibiotic resistance action target genes. Different stress response systems were mediated via cross-protection mechanism, causing stronger tolerance to an adverse environment than other ARB. Moreover, the photocatalytic inactivation mechanism of bacterial cells and a graded response of cellular stress mechanism caused differences in the intensity of the stress mechanism of antibiotic resistance action targets. E. coli DH5α resistant to cefotaxime and polymyxin, targeting synthesis of the cell wall and cell membrane, respectively, could confer greater advantages to bacterial survival and higher conjugative transfer frequency than E. coli DH5α resistant to nalidixic acid and rifampicin, which target the synthesis of DNA and RNA, respectively. This new perspective provides detailed information on the practical application of photocatalytic oxidation for inactivating ARB and hampering the spreading of ARGs in the aquatic environment.202235453030
8489140.9994Signaling molecules accelerate the transmission of antibiotic resistance genes under the stress of copper. Heavy metals can accelerate the dissemination of antibiotic resistance genes (ARGs) in aquatic environments by imposing environmental stresses. Signaling molecules play a role in bacterial communication and help bacteria adapt to environmental stresses. However, little is known whether the presence of signaling molecules has an effect on the spread of ARGs induced by heavy metals. In this study, we investigated how N-decanoyl-L-homoserine lactone (C10-HSL) affects copper-induced conjugative transfer of ARGs. We calculated the conjugative transfer frequency and measured reactive oxygen species (ROS) production, membrane permeability, and the expression of relevant genes. The results demonstrated that the addition of C10-HSL increased the conjugative transfer frequency of ARGs under copper ions (Cu(2+)) stress, showing a 7.2-fold increase under 0.5 μM Cu(2+) and 0.39 μM C10-HSL treatment compared to the control. This enhancement was associated with elevated intracellular ROS production and increased membrane permeability. The reduced conjugative transfer frequency under anaerobic conditions or with thiourea treatment supported the key role of ROS in this process. Furthermore, ROS overproduction triggered the SOS response, as evidenced by a 9-fold upregulation of recA expression. C10-HSL also modulated membrane-associated gene expression by upregulating outer membrane porins and downregulating efflux pump genes under Cu(2+)stress. This study provides a new insight into the spread of ARGs in aquatic environments.202540840413
7601150.9994Evaluating the Impact of Cl(2)(•-) Generation on Antibiotic-Resistance Contamination Removal via UV/Peroxydisulfate. The removal of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) using sulfate anion radical (SO(4)(•-))-based advanced oxidation processes has gained considerable attention recently. However, immense uncertainties persist in technology transfer. Particularly, the impact of dichlorine radical (Cl(2)(•-)) generation during SO(4)(•-)-mediated disinfection on ARB/ARGs removal remains unclear, despite the Cl(2)(•-) concentration reaching levels notably higher than those of SO(4)(•-) in certain SO(4)(•-)-based procedures applied to secondary effluents, hospital wastewaters, and marine waters. The experimental results of this study reveal a detrimental effect on the disinfection efficiency of tetracycline-resistant Escherichia coli (Tc-ARB) during SO(4)(•-)-mediated treatment owing to Cl(2)(•-) generation. Through a comparative investigation of the distinct inactivation mechanisms of Tc-ARB in the Cl(2)(•-)- and SO(4)(•-)-mediated disinfection processes, encompassing various perspectives, we confirm that Cl(2)(•-) is less effective in inducing cellular structural damage, perturbing cellular metabolic activity, disrupting antioxidant enzyme system, damaging genetic material, and inducing the viable but nonculturable state. Consequently, this diminishes the disinfection efficiency of SO(4)(•-)-mediated treatment owing to Cl(2)(•-) generation. Importantly, the results indicate that Cl(2)(•-) generation increases the potential risk associated with the dark reactivation of Tc-ARB and the vertical gene transfer process of tetracycline-resistant genes following SO(4)(•-)-mediated disinfection. This study underscores the undesired role of Cl(2)(•-) for ARB/ARGs removal during the SO(4)(•-)-mediated disinfection process.202438477971
6751160.9994Assessment of chlorine and hydrogen peroxide on airborne bacteria: Disinfection efficiency and induction of antibiotic resistance. Airborne pathogens severely threaten public health worldwide. Air disinfection is essential to ensure public health. However, excessive use of disinfectants may endanger environmental and ecological security due to the residual disinfectants and their by-products. This study systematically evaluated disinfection efficiency, induction of multidrug resistance, and the underlying mechanisms of disinfectants (NaClO and H(2)O(2)) on airborne bacteria. The results showed that airborne bacteria were effectively inactivated by atomized NaClO (>160 μg/L) and H(2)O(2) (>320 μg/L) after 15 min. However, some bacteria still survived after disinfection by atomized NaClO (0-80 μg/L) and H(2)O(2) (0-160 μg/L), and they exhibited significant increases in antibiotic resistance. The whole-genome sequencing of the resistant bacteria revealed distinct mutations that were responsible for both antibiotic resistance and virulence. This study also provided evidences and insights into possible mechanisms underlying the induction of antibiotic resistance by air disinfection, which involved intracellular reactive oxygen species formation, oxidative stress responses, alterations in bacterial membranes, activation of efflux pumps, and the thickening of biofilms. The present results also shed light on the role of air disinfection in inducing antibiotic resistance, which could be a crucial factor contributing to the global spread of antibiotic resistance through the air.202438823102
8604170.9994Reactive chlorine species inhibiting interspecies spread of antibiotic resistance via disrupting donor - Recipient cells and regulating plasmid conjugation genes. Current drinking water treatment plant (DWTP) disinfection technologies face limitations, allowing plasmid-mediated antibiotic resistance genes (ARGs) transfer to occur among viable but nonculturable (VBNC) bacteria, heightening the risk of antibiotic-resistant infections. While UV/Chlorine has been adopted to curb ARGs abundance, its impacts on the interspecies transfer of ARG-carrying plasmids remain hardly explored. This study investigated how reactive chlorine species (RCS) in the UV/Chlorine system inhibited the transfer of antibiotic resistance from antibiotic-resistant Escherichia coli (AR E. coli) to Bacillus subtilis (B.S) by inactivating both donor and recipient strains and regulating plasmid conjugation genes. RCS reduced plasmid transfer frequencies by 2.1-log and 3.2-log compared to UV or chlorine alone. By impairing (•)OH scavenging ability, it led to ROS accumulation in AR E. coli, disrupting cellular energy metabolism and DNA repair, ultimately causing DNA degradation and membrane damage, resulting in AR E. coli inactivation rather than entering the VBNC state. Additionally, RCS induced structural and intracellular disruption in B.S, compromising its capacity for plasmid uptake and stable maintenance. Finally, RCS inhibited plasmid horizontal transfer while enhancing vertical transfer, with its damage to outer membrane proteins further restricting interspecies plasmid conjugation transfer. This study provides novel insights for DWTPs to better control ARGs interspecies transfer and improve drinking water safety.202540505407
8516180.9994Graphene Oxide Inhibits Antibiotic Uptake and Antibiotic Resistance Gene Propagation. Antibiotics and antibiotic resistance genes (ARGs) in the natural environment have become substantial threats to the ecosystem and public health. Effective strategies to control antibiotics and ARG contaminations are emergent. A novel carbon nanomaterial, graphene oxide (GO), has attracted a substantial amount of attention in environmental fields. This study discovered the inhibition effects of GO on sulfamethoxazole (SMZ) uptake for bacteria and ARG transfer among microorganisms. GO promoted the penetration of SMZ from intracellular to extracellular environments by increasing the cell membrane permeability. In addition, the formation of a GO-SMZ complex reduced the uptake of SMZ in bacteria. Moreover, GO decreased the abundance of the sulI and intI genes by approximately 2-3 orders of magnitude, but the global bacterial activity was not obviously inhibited. A class I integron transfer experiment showed that the transfer frequency was up to 55-fold higher in the control than that of the GO-treated groups. Genetic methylation levels were not significant while sulI gene replication was inhibited. The biological properties of ARGs were altered due to the GO-ARG noncovalent combination, which was confirmed using multiple spectral analyses. This work suggests that GO can potentially be applied for controlling ARG contamination via inhibiting antibiotic uptake and ARG propagation.201627934199
6773190.9994Regulation of intracellular process by two-component systems: Exploring the mechanism of plasmid-mediated conjugative transfer. Plasmid-mediated conjugative transfer facilitates the dissemination of antibiotic resistance, yet the comprehensive regulatory mechanisms governing this process remain elusive. Herein, we established pure bacteria and activated sludge conjugation system to investigate the regulatory mechanisms of conjugative transfer, leveraging metformin as an exogenous agent. Transcriptomic analysis unveiled that substantial upregulation of genes associated with the two-component system (e.g., AcrB/AcrA, EnvZ/Omp, and CpxA/CpxR) upon exposure to metformin. Furthermore, downstream regulators of the two-component system, including reactive oxygen species (ROS), cytoplasmic membrane permeability, and adenosine triphosphate (ATP) production, were enhanced by 1.7, 1.4 and 1.1 times, respectively, compared to the control group under 0.1 mg/L metformin exposure. Moreover, flow sorting and high-throughput sequencing revealed increased microbial community diversity among transconjugants in activated sludge systems. Notably, the antibacterial potential of human pathogenic bacteria (e.g., Bacteroides, Escherichia-Shigella, and Lactobacillus) was augmented, posing a potential threat to human health. Our findings shed light on the spread of antibiotic resistance bacteria and assess the ecological risks associated with plasmid-mediated conjugative transfer in wastewater treatment systems.202438838482