Spread Of Antibiotic Resistance Genes Research Articles

Effects and mechanisms of polystyrene micro- and nano-plastics on the spread of antibiotic resistance genes from soil to lettuce

Effects of microplastics (MPs) and nanoplastics (NPs) on the spread of antibiotic resistance genes (ARGs) in soil-plant systems are still unclear. To investigate the spread and mechanisms of ARGs from soil to lettuce, lettuce was exposed to soil spiked with two environmentally relevant concentrations of polystyrene MPs (100 μm) and NPs (100 nm). Results showed that microorganisms that carried ARGs in soil were increased after exposure to MPs/NPs, which led to an increase in ARGs in roots. NPs were absorbed by roots and can be transported to leaves. Analysis of transcriptomics, proteomics and metabolomics indicated that high concentration of NPs regulated the expression of related genes and proteins and improved the accumulation of flavonoids in the lettuce, therefore decreased the abundance of microorganisms that contained ARGs. Our work emphasizes the size and dose influences of MPs and NPs on the spread of ARGs from soil to plant.

Nanoscale zero-valent iron alleviate antibiotic resistance risk during managed aquifer recharge (MAR) by regulating denitrifying bacterial network

The frequent occurrence of antibiotics in reclaimed water is concerning, in the case of managed aquifer recharge (MAR), it inevitably hinders further water purification and accelerates the evolutionary resistance in indigenous bacteria. In this study, we constructed two column reactors and nanoscale zero-valent iron (nZVI) amendment was applied for its effects on water quality variation, microbial community succession, and antibiotic resistance genes (ARGs) dissemination, deciphered the underlying mechanism of resistance risk reduction. Results showed that nZVI was oxidized to iron oxides in the sediment column, and total effluent iron concentration was within permissible limits. nZVI enhanced NO3--N removal by 15.5% through enriching denitrifying bacteria and genes, whereas made no effects on oxacillin (OXA) removal. In addition, nZVI exhibited a pivotal impact on ARGs and plasmids decreasing. Network analysis elucidated that the diversity and richness of ARG host declined with nZVI amendment. Denitrifying bacteria play a key role in suppressing horizontal gene transfer (HGT). The underlying mechanisms of inhibited HGT included the downregulated SOS response, the inhibited Type-Ⅳ secretion system and the weakened driving force. This study afforded vital insights into ARG spread control, providing a reference for future applications of nZVI in MAR.

Shotgun Metagenomics-Guided Prediction Reveals the Metal Tolerance and Antibiotic Resistance of Microbes in Poly-Extreme Environments in the Danakil Depression, Afar Region.

The occurrence and spread of antibiotic resistance genes (ARGs) in environmental microorganisms, particularly in poly-extremophilic bacteria, remain underexplored and have received limited attention. This study aims to investigate the prevalence of ARGs and metal resistance genes (MRGs) in shotgun metagenome sequences obtained from water and salt crust samples collected from Lake Afdera and the Assale salt plain in the Danakil Depression, northern Ethiopia. Potential ARGs were characterized by the comprehensive antibiotic research database (CARD), while MRGs were identified by using BacMetScan V.1.0. A total of 81 ARGs and 39 MRGs were identified at the sampling sites. We found a copA resistance gene for copper and the β-lactam encoding resistance genes were the most abundant the MRG and ARG in the study area. The abundance of MRGs is positively correlated with mercury (Hg) concentration, highlighting the importance of Hg in the selection of MRGs. Significant correlations also exist between heavy metals, Zn and Cd, and ARGs, which suggests that MRGs and ARGs can be co-selected in the environment contaminated by heavy metals. A network analysis revealed that MRGs formed a complex network with ARGs, primarily associated with β-lactams, aminoglycosides, and tetracyclines. This suggests potential co-selection mechanisms, posing concerns for both public health and ecological balance.

Efficacy of Fosfomycin against Extended Spectrum Beta-Lactamase-Producing Escherichia coli Isolated from Patient Urinary Cultures in the General Reference Hospital of Niamey, Niger

Urinary tract infection (UTI) is a common patient infection and a major public health problem today. The rapid spread of antibiotic resistance genes in Enterobacterales, particularly in Extended-spectrum beta-lactamases producing Escherichia coli (ESBL-E. coli), is compromising treatment with the antibiotics that are normally used. The aim of this study was to evaluate the level of susceptibility of uropathogenic ESBL-producing E. coli to fosfomycin as an alternative treatment. A total of 3369 samples of urine were received and processed in the Bacteriology Laboratory of the Niamey General Reference Hospital (NGRH) throughout 2021. Synergy testing was performed for phenotypic detection of ESBLs, and fosfomycin sensibility of ESBLs-producing uropathogenic E. coli isolates were determined using the Viteck-2 system. Of the 280 enterobacteria identified in the urine samples, 104 Escherichia coli isolates were positive to the synergy test. The average age of the patients was 54 ± 17. The age range of 46–65 years was the most affected by these infections. The female patients predominated over the male ones, with a prevalence of 51.90%, a sex ratio of 1.08. The ESBL-producing E. coli isolates were 0.97% resistant to fosfomycin. Fosfomycin is highly effective against uropathogenic ESBL-producing E. coli isolates. It could be used as an alternative treatment for both uncomplicated and complicated urinary tract infections.

Routes of dispersion of antibiotic resistance genes from the poultry farm system

Poultry farms are hotspots for the development and spread of antibiotic resistance genes (ARGs), due to high stocking densities and extensive use of antibiotics, posing a threat of spread and contagion to workers and the external environment. Here, we applied shotgun metagenome sequencing to characterize the gut microbiome and resistome of poultry, workers and their households - also including microbiomes from the internal and external farm environment – in three different farms in Italy during a complete rearing cycle. Our results highlighted a relevant overlap among the microbiomes of poultry, workers, and their families (gut and skin), with clinically relevant ARGs and associated mobile elements shared in both poultry and human samples. On a finer scale, the reconstruction of species-level genome bins (SGBs) allowed us to delineate the dynamics of microorganism and ARGs dispersion from farm systems. We found the associations with worker microbiomes representing the main route of ARGs dispersion from poultry to human populations. Collectively, our findings clearly demonstrate the urgent need to implement more effective procedures to counteract ARGs dispersion from poultry food systems and the relevance of metagenomics-based metacommunity approaches to monitor the ARGs dispersion process for the safety of the working environment on farms.

Long-term seawall barriers lead to the formation of an urban coastal lagoon with increased antibiotic resistome

Urbanization has increased the spread of antibiotic resistance genes (ARGs) impacting urban aquatic ecosystems and threatening human health. However, an overview of the antibiotic resistome in artificial coastal lagoons formed by coastal seawall construction is unclear. This study investigated the resistome of sediment in a coastal lagoon, established for over 60 years and found that the composition of the resistome in the lagoon sediments associated with the seawall significantly differed from that of marine sediment external to the seawall. Moreover, the diversity, number, relative abundance, and absolute abundance of the antibiotic resistome in the lagoon sediments were significantly higher compared to marine sediment. Network analyses revealed that more co-occurrences were found in lagoon sediment between bacterial communities, ARGs and mobile genetic elements (MGEs) than in marine sediments, suggesting that bacteria in lagoon sediments may be associated with multiple antibiotic resistances. Random forest and structural equation models showed that an increase in the absolute abundance of MGEs had a concomitant effect on the absolute abundance and diversity of ARGs, whereas increasing salinity decreased the absolute abundance of ARGs. This study provides a basis to assess the risk of resistome diffusion and persistence in an artificial coastal lagoon.

Inhibition mechanisms of biochar-derived dissolved organic matter to triclosan photodegradation: A remarkable role of aliphatics

Endocrine disrupting chemicals like triclosan (TCS) have been thought to be an emergent environmental pollutant. The ubiquitous dissolved organic matter (DOM) is able to interrelate with TCS and hamper its phototransformation. However, how the components in DOM can inhibit the photodegradation of DOM/TCS complex is largely unknown. Herein, we discovered that TCS photodegradation with biochar-derived DOM (BDOM) was interfered by both binding affinity and reactive oxygen species (ROS) productivity. BDOM can not only stimulate TCS photodegradation by producing ROS, but also inhibit the removal of TCS through the interactions between BDOMs and TCS. The quantification of BDOM's impact on TCS photodegradation revealed that BDOM hampered TCS removal with the proportion of −7.95 to −11.24% at pH 8.5, but strengthened it to 13.20% at pH 7.0. Binding process was more easily to inhibit TCS photodegradation in molecular form, while anionic TCS photodegradation was dominated by ROS productivity. Different inhibition mechanisms were involved in TCS photodegradation depending on the components of BDOMs. The hydroxyls and aromatic carbonyls might have hindered the attack of ROS on the phenolic hydroxyl of TCS via hydrogen bond interaction or π-π electron donor-acceptor interaction. Through hydrophobic interaction, the mobile aliphatics could greatly shield TCS to prevent ROS attack by wrapping or twining TCS, playing a significant role in inhibiting TCS removal. Results from this present study can afford a new viewpoint in elucidating the function of BDOMs in the phototransformation of organics and decrease the spread of antibiotic resistance genes.

Concentrations, distribution, and key influencing factors of antibiotic resistance genes and bacterial community in water and reared fish tissues in a typical tilapia farm in South China

Although previous studies have investigated the occurrence of antibiotic resistance genes (ARGs) in aquaculture, few have monitored the concentrations and propagation of ARGs in biological tissues or investigated the key factors influencing their spread in aquaculture. This study investigated the concentration, propagation, and distribution of ARGs and bacterial communities in water sources, pond water, and tilapia tissues, and their key influencing factors, in a typical tilapia farm. ErmF, sul1, and sul2 were the dominant ARGs with high concentrations. The total concentrations of ARGs (TCAs) in tilapia tissues decreased in the following order: stomach > scales > intestine > gills (P < 0.05). Redundancy analysis and multiple linear regression revealed that suspended solids (SS) and chemical oxygen demand (COD) were positively correlated with the dominant ARGs ermF sul2, and the TCAs (P < 0.05); additionally, Chloroflexi and Bacteroidetes in tilapia aquaculture water were positively correlated with the dominant ARGs ermF and sul2, as well as the TCAs (P < 0.05). This study suggests that SS and COD were the key factors driving the distribution and spread of ARGs in tilapia aquaculture water. Additionally, Chloroflexi and Bacteroidetes were the key bacterial flora affecting the propagation of ARGs in tilapia aquaculture systems.

Free-living lifestyle preferences drive the antibiotic resistance promotion during drinking water chlorination

The risk associated with antibiotic resistance genes (ARGs) in size-fractionated bacterial community during drinking water chlorination remains unclear, and is of paramount importance for risk mitigation through process selection and optimization. This study employed metagenomic approaches to reveal the alterations of ARGs, their potential functions and hosts within the free-living and particle-associated fractions. The total relative abundance of ARGs, mobile genetic elements (MGEs), and virulence factor genes (VFGs) significantly increased in the free-living fraction after chlorination. The contribution of the free-living fraction to the ARG relative abundance rose from 16.40 ± 1.31 % to 93.62 ± 0.47 % after chlorination. Multidrug resistance genes (e.g. mexF and mexW) were major contributors, and their co-occurrence with MGEs in the free-living fraction was enhanced after chlorination. Considering multiple perspectives, including presence, mobility, and pathogenicity, chlorination led to a significant risk of the antibiotic resistome in the free-living fraction. Moreover, potential functions of ARGs, such as cell wall/membrane/envelope biogenesis, defense mechanisms, and transcription in the free-living fraction, were intensified following chlorination. Potential pathogens, including Pseudomonas aeruginosa, Pseudomonas alcaligenes, and Acinetobacter junii, were identified as the predominant hosts of multidrug resistance genes, with their increased abundances primarily contributing to the rise of the corresponding ARGs. Overall, alterations of hosts as well as enhancing mobility and biological functions could collectively aid the proliferation and spread of ARGs in the free-living fraction after chlorination. This study provides novel insights into antibiotic resistance evolution in size-fractionated bacteria community and offers a management strategy for microbiological safety in drinking water.

Ozone micron bubble pretreatment for antibiotic resistance genes reduction in hospital wastewater treatment

Ozone micron bubble (OMB) treatment offers a promising approach to effectively eliminate Antibiotic Resistance Genes (ARGs) from infectious medical wastewater and mitigate the threat of drug resistance transmission. This study evaluated the effectiveness of OMB treatment for reducing ARGs from infectious medical wastewater in laboratory and on-site pilot treatment setups. In part, the presence of antibiotic residues in a hospital wastewater treatment plant (WWTP) and the impact of hospital wastewater on the distribution of ARGs in a wastewater collection system were also investigated. The results of wastewater collection system survey revealed a high prevalence of ARGs in the system, particularly mcr-1, largely originating from medical wastewater discharges. Furthermore, analysis of antibiotic residues in the hospital wastewater treatment system showed significant accumulation, particularly of quinolone antibiotics, in the biomass of the biological oxidation tank, suggesting a potential risk of ARG proliferation within the system. Comparison of wastewater samples from domestic and hospital WWTPs revealed a relatively higher abundance of ARGs in the latter, with differences ranging from 2.2 to sixfold between corresponding locations in the treatment plants. Notably, the biological oxidation unit of both WWTPs exhibited a greater proportion of ARGs among all sampled points, indicating the potential proliferation of ARGs within the biomass of the treatment units. ARG degradation experiments showed that OMB treatment resulted in a significantly lower CT value (9.3 mg O3 L−1 min) compared to ozone coarse bubble treatment (102 mg O3 L−1 min) under identical test conditions. Moreover, the use of OMB on site significantly reduced the accumulation of ARGs in hospital wastewater, underscoring its potential as an effective solution for mitigating ARG spread.

Identifying ARG-carrying bacteriophages in a lake replenished by reclaimed water using deep learning techniques

As important mobile genetic elements, phages support the spread of antibiotic resistance genes (ARGs). Previous analyses of metaviromes or metagenome-assembled genomes (MAGs) failed to assess the extent of ARGs transferred by phages, particularly in the generation of antibiotic pathogens. Therefore, we have developed a bioinformatic pipeline that utilizes deep learning techniques to identify ARG-carrying phages and predict their hosts, with a special focus on pathogens. Using this method, we discovered that the predominant types of ARGs carried by temperate phages in a typical landscape lake, which is fully replenished by reclaimed water, were related to multidrug resistance and β-lactam antibiotics. MAGs containing virulent factors (VFs) were predicted to serve as hosts for these ARG-carrying phages, which suggests that the phages may have the potential to transfer ARGs. In silico analysis showed a significant positive correlation between temperate phages and host pathogens (R = 0.503, p < 0.001), which was later confirmed by qPCR. Interestingly, these MAGs were found to be more abundant than those containing both ARGs and VFs, especially in December and March. Seasonal variations were observed in the abundance of phages harboring ARGs (from 5.62 % to 21.02 %) and chromosomes harboring ARGs (from 18.01 % to 30.94 %). In contrast, the abundance of plasmids harboring ARGs remained unchanged. In summary, this study leverages deep learning to analyze phage-transferred ARGs and demonstrates an alternative method to track the production of potential antibiotic-resistant pathogens by metagenomics that can be extended to microbiological risk assessment.

Key taxa and mobilome-mediated responses co-reshape the soil antibiotic resistome under dazomet fumigation stress

Agrochemicals are emergingly being implicated in the widespread dissemination of antibiotic resistance genes (ARGs) in agroecosystems. However, minimal research exists on the disturbance of fumigant on soil ARGs. Focusing on a typical fumigant dazomet in a simulated soil microcosm, we characterized the dazomet-triggered timely response and longstanding dynamic of ARGs at one-fold and two-fold field recommended doses using metagenome and quantitative PCR. Dazomet treatments reduced 13.17%-69.98% of absolute abundance of 16S rRNA gene and targeted ARGs, but, awfully, boosted diversity and relative abundance of ARGs up to 1.33–1.60 and 1.62–1.90 folds, respectively. Approximately 77.28% of changes in relative abundance of ARGs could be explained by bacterial community and mobile genetic elements (MGEs). Mechanistically, primary hosts of ARGs shifted from Proteobacteria (control) to Firmicutes and Actinobacteria (treatments) accompanied with corresponding changes in their abundance by combining community analysis, host tracking analysis and antibiotic resistant bacteria assay. Meanwhile, dazomet exposure significantly increased the incidence of MGEs and stimulated the conjugation of antibiotic-resistant plasmid. In addition, absolute abundance of targeted ARGs gradually recovered in the post-fumigation stage. Collectively, our results elucidate the dazomet-triggered emergence and spread of soil ARGs and highlight the importance of navigating toward rational use of fumigant in agricultural fields.

Longitudinal metagenomic study reveals the dynamics of fecal antibiotic resistome in pigs throughout the lifetime

BackgroundThe dissemination of antibiotic resistance genes (ARGs) poses a substantial threat to environmental safety and human health. Herein, we present a longitudinal paired study across the swine lifetime from birth to market, coupled with metagenomic sequencing to explore the dynamics of ARGs and their health risk in the swine fecal microbiome.ResultsWe systematically characterized the composition and distribution of ARGs among the different growth stages. In total, 829 ARG subtypes belonging to 21 different ARG types were detected, in which tetracycline, aminoglycoside, and MLS were the most abundant types. Indeed, 134 core ARG subtypes were shared in all stages and displayed a growth stage-associated pattern. Furthermore, the correlation between ARGs, gut microbiota and mobile genetic elements (MGEs) revealed Escherichia coli represented the main carrier of ARGs. We also found that in most cases, the dominant ARGs could be transmitted to progeny piglets, suggesting the potential ARGs generation transmission. Finally, the evaluation of the antibiotic resistance threats provides us some early warning of those high health risk ARGs.ConclusionsCollectively, this relatively more comprehensive study provides a primary overview of ARG profile in swine microbiome across the lifetime and highlights the health risk and the intergenerational spread of ARGs in pig farm.Graphical

The pH-specific response of soil resistome to triclocarban and arsenic co-contamination

Heavy metals as well as disinfectants affect the spread of antibiotic resistance genes (ARGs) in soil microbes, however, their cumulative impacts on the proliferation of ARGs are not well studied. In addition, both the chemical stability/availability and ARG profiles are affected by the soil pH, but it has never been considered in the systematic evaluation of soil resistome. In the present study, a microcosm experiment was conducted to study the combined effects of arsenic and triclocarban on the resistome in soil samples with variable pH (pH 4–7). The simultaneous additions of arsenic and triclocarban increase the ARG abundance at pH > 6, because of the intensive co-selective pressures triggered by the increase in concentrations of available arsenic and triclocarban. The occurrence of multidrug ARGs increases with the addition of arsenic and triclocarban, due to the preferred selection of their functional flexibility. The presence of arsenic and triclocarban is strongly related to the spread of MGEs affecting the soil resistome. Furthermore, pH alters the patterns of microbial inhabitants, increasing the relative abundance of Bacteroidota and Proteobacteria and contributing to the prevalence of tetracycline and sulfonamide ARGs at neutral pH. These findings have insight that the effects of arsenic and triclocarban co-contamination on the soil antibiotic resistome is pH dependent.

The Antimicrobial Resistance of Staphylococcus Haemolyticus Isolated from Patients in Taif, Saudi Arabia

Background: The spread of antibiotic-resistance genes in ecosystems has led to the emergence of antibiotic- resistant bacteria, leading to various antibiotic-resistant diseases worldwide. Materials and methods: This study aimed to characterize mute-drug resistant Staphylococci isolates from urine and wounds. We obtained 400 bacterial isolates that were tested for their pathogenicity through cultivation on blood agar, Vitek instrument was used for characterization of different antibiotic sensitivity, while PCR was used to detect the resistance gene. Excel and SPSS were used to analyze the data. All samples were obtained after institutional ethics review and participant's-consents Result: Of 400 160=40% females, 60%=240 were males) isolates were carried out from. Out of 1640 twenty-one were beta-hemolysis almost of them were described as extensive Multi-drug resistant isolates were 4(21) as they resist 10 antibiotics, 1(21) resist nine antibiotics, 7(21) resist eight antibiotics, 3(21) against seven, 2(21) six antibiotics, 2(21) resist five antibiotics,1(21) resist four antibiotic and 1(21) resist two antibiotics. These twenty-one were positive in mecA gene amplification through PCR technique but negative for the Vancomycin resistance gene. Conclusion: There are high mecA genes among clinical isolates in our study further studies with a high sample size Staphylococcus haemolyticous is recommended.

Interaction of pAsa5 and pAsa8 Plasmids in Aeromonas salmonicida subsp. salmonicida.

The plasmid known as pAsa5 is present in Aeromonas salmonicida subsp. salmonicida, a fish pathogen. The pAsa5 plasmid carries genes that are essential for the bacterium's virulence. Recombination events are known to occur in pAsa5, resulting in the loss of certain segments or the acquisition of additional genetic elements. For example, the transposon carried by the large pAsa8 plasmid was found to be inserted into the pAsa5 plasmid in the SHY16-3432 strain, enabling the addition of antibiotic resistance genes to this plasmid, which does not normally possess any. In this study, we present the isolation of additional strains carrying pAsa8. Further analyses of these strains revealed that a fusion between pAsa5 and the complete version of pAsa8 is possible. The pAsa8 transposon insertion in pAsa5 seen in the SHY16-3432 strain appears to be an aberrant event compared to the fusion of the two full-length plasmids. A 22-nucleotide sequence, present in both plasmids, serves as the site for the fusion of the two plasmids. Moreover, it is possible to introduce pAsa8 through conjugation into naive strains of A. salmonicida subsp. salmonicida and once the plasmid is within a new strain, the fusion with pAsa5 is detectable. This study reveals a previously unexplored aspect of pAsa5 plasmid biology, highlighting an additional risk for the spread of antibiotic resistance genes in A. salmonicida subsp. salmonicida.

Mass-immigration shapes the antibiotic resistome of wastewater treatment plants

Wastewater treatment plants (WWTPs) are the hotspots for the spread of antibiotic resistance genes (ARGs) into the environment. Nevertheless, a comprehensive assessment of the city-level and short-term daily (inter-day) variations of ARG profiles in the whole process (influent-INF, activated sludge-AS and effluent-EF) of WWTPs is still lacking. Here, 285 ARGs and ten mobile gene elements were monitored in seven WWTPs in Xiamen for seven days via high-throughput qPCR. The average daily load of ARGs to WWTPs was about 1.32 × 1020 copies/d, and a total of 1.56 × 1018 copies/d was discharged to the environment across the entire city. Stochastic processes were the main force determining the assembly of ARG communities during sampling campaign, with their relative importance ranked in the order of INF > EFF > AS. There're little daily variations in ARG richness, abundance, β-diversity composition as well as assembly mechanisms. The results of SourceTracker, variation partitioning analysis, and hierarchical partitioning analysis indicated that bacteria and ARGs from upstream treatment processes played an increasingly dominant role in shaping ARG communities in AS and EFF, respectively, suggesting the importance of mass-immigration of bacteria and ARGs from the source on ARG transport in wastewater treatment processes. This emphasizes the need to revise the way we mitigate ARG contamination but focus on the source of ARGs in urban wastewater.

Incomplete degradation of aromatic–aliphatic copolymer leads to proliferation of microplastics and antibiotic resistance genes

Biodegradable plastics (BDPs) have attracted extensive attention as an alternative to conventional plastics. BDPs could be mineralized by composting, while the quality of compost affected by the presence of BDPs and the residual microplastics (MPs) has not been well evaluated. This study aimed to explore the MPs release potential and environmental implications of commercial BDPs (aromatic−aliphatic copolymer) films in uncontrolled composting. Results showed that the molecular weight of BDPs decreased by >60% within 60 d. However, the non-extracted organic matter and wet-sieving measurements indicated that MPs continuously released and accumulated during regular composting. The average MPs release potential (0.1–5 mm) was 134.6 ± 18.1 particles/mg (BDPs), which resulted in 103–104 particles/g dw in compost. The plastisphere of MPs showed a significantly higher (0.95–16.76 times) abundance of antibiotic resistance genes (ARGs), which resulted in the rising (1.34–2.24 times) of ARGs in compost heaps, in comparison to the control groups. Overall, BDPs promote the spread of ARGs through the selective enrichment of bacteria and horizontal transfer from released MPs. These findings confirmed that BDPs could enhance the release potential of MPs and the dissemination of ARGs, which would promote the holistic understanding and environmental risk of BDPs.

Occurrence and removal prediction of pharmaceuticals positively correlated with antibiotic resistance genes in wastewater treatment processes

Wastewater treatment plants (WWTPs) are important source of pharmaceuticals in the environment, identifying their relationship with antibiotic resistance genes (ARGs) and removal behavior is important for risk control. In this study, the correlations of common pharmaceuticals (including antibiotics and non-antibiotics) and ARGs both in wastewater and sludge were investigated, and machine learning was applied to predict the removal efficiencies of typical pharmaceuticals positively correlated with ARGs. Among the 23 kinds of target pharmaceuticals, both antibiotics and non-antibiotics were found to be positive with typical ARGs in wastewater (e.g. correlation coefficients between caffeine and blaTEM, aadD and qnrS were 0.738, 0.609, 0.936, p < 0.01) but negative in sludge (e.g. correlation coefficients between ofloxacin and tetO, tetW and qnrS were −0.922, −0.933 and −0.902, p < 0.01), indicating the high risk of pharmaceuticals in wastewater promoting ARG spread. Furthermore, based on pharmaceutical removal efficiencies in different wastewater treatment processes in this and previous studies, the removal efficiencies of typical pharmaceuticals highly correlated with ARGs were well predicted through process operation parameters and wastewater characteristics by Random Forest model. HRT and temperature were identified as the most important explanatory variables. This study could provide comprehensive references for controlling pharmaceuticals in WWTPs.

The Antibiotic Resistome and Its Association with Bacterial Communities in Raw Camel Milk from Altay Xinjiang.

Raw camel milk is generally contaminated with varied microbiota, including antibiotic-resistant bacteria (ARB), that can act as a potential pathway for the spread of antibiotic resistance genes (ARGs). In this study, high-throughput quantitative PCR and 16S rRNA gene-based Illumine sequencing data were used to establish a comprehensive understanding of the antibiotic resistome and its relationship with the bacterial community in Bactrian camel milk from Xinjiang. A total of 136 ARGs and up to 1.33 × 108 total ARG copies per gram were identified, which predominantly encode resistance to β-lactamas and multidrugs. The ARGs' profiles were mainly explained by interactions between the bacteria community and physicochemical indicators (77.9%). Network analysis suggested that most ARGs exhibited co-occurrence with Corynebacterium, Leuconostoc and MGEs. Overall, raw camel milk serves as a reservoir for ARGs, which may aggravate the spread of ARGs through vertical and horizontal gene transfer in the food chain.