Research on the microbiome and resistome in polar environments, such as the Arctic, is crucial for understanding the emergence and spread of antibiotic resistance genes (ARGs) in the environment. In this study, soil and reindeer faeces samples collected from Ny-Ålesund (Svalbard, High Arctic) were examined to analyze the microbiome, ARGs, and biocide/metal resistance genes (BMRGs). The dominant phyla in both soil and faeces were Pseudomonadota, Actinomycetota, and Bacteroidota. A total of 2,618 predicted Open Reading Frames (ORFs) containing antibiotic resistance genes (ARGs) were detected. These ARGs belong to 162 different genes across 17 antibiotic classes, with rifamycin and multidrug resistance genes being the most prevalent. We focused on investigating antibiotic resistance mechanisms in the Ny-Ålesund environment by analyzing the resistance genes and their biological pathways. Procrustes analysis demonstrated a significant correlation between bacterial communities and ARG/BMRG profiles in soil and faeces samples. Correlation analysis revealed that Pseudomonadota contributed most to multidrug and triclosan resistance, while Actinomycetota were predominant contributors to rifamycin and aminoglycoside resistance. The geochemical factors, SiO42- and NH4+, were found to significantly influence the microbial composition and ARG distribution in the soil samples. Analysis of ARGs, BMRGs, virulence factors (VFs), and pathogens identified potential health risks associated with certain bacteria, such as Cryobacterium and Pseudomonas, due to the presence of different genetic elements. This study provided valuable insights into the molecular mechanisms and geochemical factors contributing to antibiotic resistance and enhanced our understanding of the evolution of antibiotic resistance genes in the environment.

The gut microbiome plays a crucial role in maintaining animal health and is influenced by various factors, including light exposure; however, the response in laying hens of the gut microbiome to intermittent light regimes and the related impact on antibiotic resistance genes (ARGs) remain poorly understood. In this study, we divided 20-week-old laying hens into two groups. These groups were exposed to either continuous normal light or intermittent light for 8 weeks. The feces and cecal contents of laying hens were collected for analysis. Metagenomic analysis of both feces and cecal content samples revealed significant shifts in the microbial composition and abundance of ARGs under intermittent light exposure compared to normal light exposure (P < 0.05). Furthermore, metabolomic analysis of the cecal contents revealed substantial alterations in the abundance and composition of ARGs and mobile genetic elements (MGEs) in response to intermittent light exposure (P < 0.05). Network analysis revealed intricate co-occurrence patterns among bacterial communities, metabolites, and ARGs, highlighting correlations between Bacteroidetes species, ARGs, and metabolites. Although certain bacterial species showed differential associations, the dominant bacteria carrying ARGs or MGEs had relatively low numbers, suggesting that other bacterial communities may have had a greater influence on ARG dissemination. Moreover, our observations highlight the crucial role of metabolites as mediators between bacterial communities and ARGs, providing novel insights into the dynamics of antibiotic resistance development. Our findings underscore the impact of intermittent light exposure on ARG proliferation in poultry farming and emphasize interconnections among ARGs, bacterial communities, and metabolic pathways. The results underscore the importance of considering both microbial communities and metabolic processes to understand antibiotic resistance in agricultural settings.

Antibacterial resistance in wild animals has been increasingly reported worldwide, even though they are usually not directly exposed to clinically relevant antibiotics. Crested ibis, one of the rarest birds in the world, usually forages in paddy fields and prefer to nest and breed near villages that is greatly influenced by anthropogenic activities. We sampled the feces of crested ibises, as well as their habitat environment samples, to explore the pollution characteristics of heavy metals, antibiotics and antibiotic resistance genes (ARGs). Results showed that the pollution characteristics of heavy metals, antibiotic, ARGs and gut microbiota of crested ibis were more related by host lifestyle and habitats. Captive ibises had higher relative abundances of the total ARGs and tetracycline concentrations compared with feralization and wild ibises, while the heavy metal contents had shown the opposite result. The Characteristics of pollutants in the corresponding environmental samples also exhibited high similarity with the results of fecal samples. The relative abundances of Proteobacteria and Actinobacteria were significantly different between captive and wild individuals, while the abundance of majority bacterial genera was generally higher in wild populations. The concentrations of heavy metals in soil (Cd, Cu and Zn) and water (Cd, Cu, Zn and Cr) were both exceeded the background soil levels or surface water quality standards, suggesting multi-element contamination in the habitat. Ecological risk assessments of soils by Igeo and Er showed that the habitats of wild ibises were heavily and moderately contaminated by Cd, which would possibly pose a threat to the health of ibises. PLS-PM analysis indicated that microbial compositions and residual antibiotics had the most substantial impact on the dynamic changes in ARGs of ibis. Overall, this work provides a comprehensive understanding of the characteristics, risks of those contaminations, and their effects on the ARGs in the habitat of crested ibis.

Urban parks play a significant role in urban ecosystems and are strongly associated with human health. Nevertheless, the biological contamination of urban parks - opportunistic pathogens and antibiotic resistance genes (ARGs) - has been poorly reported. Here, metagenomic and 16 S rRNA sequencing methods were used to study the distribution and assembly of opportunistic pathogens and ARGs in soil and water from nine parks in Lanzhou city, and further compared them with local human gut microbiomes to investigate the potential transmission risk. Our results revealed that the most important type of drug resistance in urban parks was multidrug resistance, with various resistance mechanisms. Approximately half of ARGs were shared between human gut and park environment, and it was noteworthy that cross-species transmission might exist among some high-risk ARGs, such as mepA and mdtE, with a significant enrichment in human gut. Metagenomic binning uncovered several bacterial genomes carrying adjacent ARGs, MGEs, and virulence genes, indicating a possibility that these genes may jointly transfer among different environments, particularly from park environment to human. Our results provided a reference point for the management of environmental pollutants in urban parks.

Pathogenic microorganisms with antibiotic resistance genes (ARGs) pose a serious threat to public health and soil ecology. Although new drugs and available antibacterial materials can kill ARG carriers but accidentally kill beneficial microorganisms. Therefore, the rapid enrichment and separation of ARGs and their carriers from soil is becoming an important strategy for controlling the diffusion of ARGs. Hydroxamate siderophore (HDS) has gained widespread attentions for its involvement in trace element transfer among microorganisms in the soil environment, we thus explored an in-situ trapping-enrichment method for ARGs and their carriers via a small molecular HDS secreted by Pseudomonas fluorescens HMP01. In this study, we demonstrate that HDS significantly in-situ traps and enriches certain ARGs, including chloramphenicol, MLS, rifamycin, and tetracycline resistance genes in the soil environment. The enrichment efficiencies were 1473-fold, 38-fold, 17-fold, and 5-fold, respectively, higher than those in the control group. Specifically, the primary enriched ARGs were rpoB, mphL, catB2, and tetA(60), and Bacillus, Rhizobium, Rossellomorea, and Agrobacterium were hosts for these ARGs. This enrichment was caused by the upregulation of chemotaxis genes (e.g., cheW, cheC, and cheD) and rapid biofilm formation within the enriched bacterial population. Notably, representative ARGs such as cat, macB, and rpoB were significantly reduced by 36%, 85.7%, and 72%, respectively, in the paddy soil after HDS enrichment. Our research sheds light on the potential application of siderophore as a rapping agent for the eco-friendly reduction of ARGs and their carriers in soil environments.

We here present CLUES2, a full-likelihood method to infer natural selection from sequence data that is an extension of the method CLUES. We make several substantial improvements to the CLUES method that greatly increases both its applicability and its speed. We add the ability to use ancestral recombination graphs on ancient data as emissions to the underlying hidden Markov model, which enables CLUES2 to use both temporal and linkage information to make estimates of selection coefficients. We also fully implement the ability to estimate distinct selection coefficients in different epochs, which allows for the analysis of changes in selective pressures through time, as well as selection with dominance. In addition, we greatly increase the computational efficiency of CLUES2 over CLUES using several approximations to the forward-backward algorithms and develop a new way to reconstruct historic allele frequencies by integrating over the uncertainty in the estimation of the selection coefficients. We illustrate the accuracy of CLUES2 through extensive simulations and validate the importance sampling framework for integrating over the uncertainty in the inference of gene trees. We also show that CLUES2 is well-calibrated by showing that under the null hypothesis, the distribution of log-likelihood ratios follows a χ2 distribution with the appropriate degrees of freedom. We run CLUES2 on a set of recently published ancient human data from Western Eurasia and test for evidence of changing selection coefficients through time. We find significant evidence of changing selective pressures in several genes correlated with the introduction of agriculture to Europe and the ensuing dietary and demographic shifts of that time. In particular, our analysis supports previous hypotheses of strong selection on lactase persistence during periods of ancient famines and attenuated selection in more modern periods.

In contemporary society, the improper use of antibiotics leads to their persistent presence in the ecological environment. Due to the diverse physical and chemical properties of antibiotics, their spatial and temporal distribution in the environment varies. Moreover, antibiotics can stimulate the emergence of antibiotic resistance genes (ARGs), which complicates the monitoring and regulation of antibiotics and poses a significant threat to both aquatic and terrestrial environments. This study investigated the distribution of 15 antibiotics and 11 typical ARGs across four categories at 19 sites of drinking water sources in Wuhan, China. The findings revealed that the concentration of antibiotics during the dry season (nd~61,883 ng/L) was significantly higher compared to both the normal water season (nd~49,883 ng/L) and the wet season (nd~28,686 ng/L). Sulfamethoxazole (SMX), sulfamethoxazole (SMD), sulfadiazine (SD), and roxithromycin (RTM) were the predominant antibiotics in the target water environments. The study indicated that most of the antibiotics analyzed posed little to no risk to aquatic organisms. The primary ARGs detected in the surface water of the study area were sul1, qnrD, and tetO. Furthermore, some ARGs showed a negative correlation with their respective antibiotics. Additional research is necessary to evaluate the impact of these emerging pollutants (antibiotics and ARGs) on the safety of high-quality drinking water for residents in Wuhan City.

The overuse and misuse of antibiotics have accelerated the selection of antibiotic-resistant bacteria, significantly impacting human, animal, and environmental health. As aquatic environments are vulnerable to antibiotic resistance, suitable management practices should be adopted to tackle this phenomenon. Here we show an effective, nature-based solution for reducing antibiotic resistance from actual wastewater. We utilize a bioreactor that relies on benthic (biofilms) and planktonic microbial communities to treat secondary effluent from a small urban wastewater treatment plant (<10,000 population equivalent). This treated effluent is eventually released into the local aquatic ecosystem. We observe high removal efficiency for genes that provide resistance to commonly used antibiotic families, as well as for mobile genetic elements that could potentially aid in their spread. Importantly, we notice a buildup of sulfonamide (sul1 and sul2) and tetracycline (tet(C), tet(G), and tetR) resistance genes specifically in biofilms. This advancement marks the initial step in considering this bioreactor as a nature-based, cost-effective tertiary treatment option for small UWWTPs facing antibiotic resistance challenges.

The excessive use of antibiotics, disinfectants, and drugs in livestock and poultry breeding has resulted in a rise in the presence of antibiotic resistance genes (ARGs). Antibiotic-resistant bacteria (ARB) and ARGs have been widely found in animal feces, farm wastewater, and farm air. ARGs can not only spread across media through adsorption and migration, but also transfer resistance across bacterial genera through horizontal gene transfer. Livestock breeding has become a fixed and unavoidable source of ARGs in the environment. Existing technologies for controlling ARGs, such as composting, disinfection, and sewage treatment, are not efficient in removing ARB and ARGs from waste. Furthermore, the remaining ARGs still possess a strong capacity for dissemination. At present, antibiotics used in animal husbandry are difficult to replace in a short period of time. The growth and potential risks of resistance genes in livestock and poultry breeding sources in the receiving environment are not yet clear. In this paper, we summarize the current situation of ARGs in the livestock and poultry breeding environment. We also explain the key environmental processes, main influencing factors, and corresponding ecological risks associated with ARGs in this environment. The advantages and disadvantages of current technologies for the removal of ARGs are primarily discussed. There is a particular emphasis on clarifying the spatiotemporal evolution patterns and environmental process mechanisms of ARGs, as well as highlighting the importance and urgency of developing efficient pollution control technologies.

The increase in the prevalence of carbapenem-resistant Gram-negative bacteria, in particular Acinetobacter baumannii (CRAB) and Pseudomonas aeruginosa (CRPA), poses a serious threat for public health worldwide. This article reviews the alarming data on the prevalence of infections caused by CRAB and CRPA pathogens and their presence in hospital and municipal wastewater, and it highlights the environmental impact of antibiotic resistance. The article describes the key role of antibiotic resistance genes (ARGs) in the acquisition of carbapenem resistance and sheds light on bacterial resistance mechanisms. The main emphasis was placed on the transfer of ARGs not only in the clinical setting, but also in the environment, including water, soil, and food. The aim of this review was to expand our understanding of the global health risks associated with CRAB and CRPA in hospital and municipal wastewater and to analyze the spread of these micropollutants in the environment. A review of the literature published in the last decade will direct research on carbapenem-resistant pathogens, support the implementation of effective preventive measures and interventions, and contribute to the development of improved strategies for managing this problem.