Transmission mechanism of antibiotic resistance genes and their differences between water and sediment in the Weihe River Basin.

Antibiotic resistance genes (ARGs) are emerging microbial pollutants that are regulated by many factors and pose potential threats to aquatic environments. In this study, we used network analysis, correlation analysis, and constructed models based on metagenomic sequencing results to explore the spatial patterns, impact mechanisms, transmission risks and differences in ARGs in the water and sediment of the Weihe River Basin. The findings revealed notable disparities in ARGs, mobile genetic elements (MGEs), and bacterial communities. In the sediment, the abundance of ARGs was considerably greater than that in water. Moreover, the percentage of ARGs shared by the two components reached a value of 85.8%. Through network analysis, it was determined that the presence of 16 MGEs and 20 bacterial phyla was strongly associated with ARGs (R2 > 0.7, P < 0.05). The Mantel test showed that abiotic factors including DO, pH, nutrients, and heavy metals played important roles in the distribution of ARGs (P < 0.05). A structural equation model revealed that the key factors influencing the distribution of ARGs in water were bacterial diversity and environmental parameters (standardized effects of -0.730 and -0.667), and those in sediment were bacterial diversity and MGEs (standardized effects of -0.751 and 0.851). Neutral modeling indicated that deterministic processes played an important role in the assembly of ARGs in the water of the Weihe River Basin, and stochastic processes were dominant in the sediment. There was a highly significant positive linear correlation between ARGs and pathogens, and there was more complex co-occurrence in the water than in the sediment (R2 > 0.9, P < 0.05), with stronger migration and transmission occurring. Exploring ARGs in large-scale watersheds is immensely important for elucidating their traits and transmission mechanisms and consequently paving the way for the formulation of efficient strategies to mitigate resistance threats.

Enhancing short-chain fatty acids production via acidogenic fermentation of municipal sewage sludge: Effect of sludge characteristics and peroxydisulfate pre-oxidation.

This study first employed a combined pretreatment of low-dose peroxy-disulfate (PDS) and initial pH 10 to promote short-chain fatty acids (SCFAs) production via acidogenic fermentation using different types of sewage sludge as substrates. The experimental results showed that the yield of maximal SCFAs and acetate proportion after the combined pretreatment were 1513.82 ± 28.25 mg chemical oxygen demand (COD)/L and 53.64%, and promoted by 1.28 and 1.56 times higher, respectively, compared to the sole initial pH 10 pretreatment. Furthermore, in terms of the disintegration degree of sewage sludge, it increased by more than 18% with the combined pretreatment compared to the pretreatment of sole initial pH 10. Waste-activated sludge (WAS) from A2/O and Bardenpho processes were more biodegradable, explained by the 1.47- and 1.35-times higher disintegration rate than those from oxidation ditch and they favored acetate dominant fermentation. Correlation analysis revealed a strong correlation (p ≤ 0.01) between SCFAs production and soluble COD, total proteins, proteins in soluble-extracellular polymeric substances (SEPS), total polysaccharides, and polysaccharides in SEPS. Mechanism explorations showed that preoxidation with PDS enhanced the solubilization and biodegradability of complex substrates, and altered the microbial community structure during the fermentation process. Firmicutes and Tetrasphaera were proven to play a key role in improving SCFA production, especially in promoting acetate production by converting additional SCFAs into acetate. Additionally, the addition of PDS greatly promoted sulfur and iron-related metabolic activities. Finally, the combined pretreatment was estimated to be a cost-effective solution for reutilizing and treating Fe-sludge.

Effects of water environmental factors and antibiotics on bacterial community in urban landscape lakes.

The presence of antibiotics can affect the natural microbial community and exert selective pressure on the environment's microorganisms. This study focused on three types of urban landscape lakes in Xi'an that were closely related to human activities. By combining basic water quality indicators, antibiotic occurrence status, bacterial communities and their potential metabolic functions, Spearman correlation coefficient and redundancy analysis were used to explore the relationship between them, and further explore the impact mechanism of environmental factors and antibiotics on bacterial community structure. The results showed that ofloxacin, erythromycin, and roxithromycin were the main types of antibiotics in the three landscape lakes, with low ecological risks, and there was a clear clustering of antibiotic occurrence. Proteobacteria was the most abundant bacterial phylum, and each lake had its own unique dominant bacteria, which indicates that they are influenced by varying water sources, pollution, and other nearby environments. Statistical analysis showed that pH and nitrogen nutrients were the most critical environmental factors affecting bacterial communities (P<0.01), while tetracyclines and lincomycins were the antibiotics that had a significant impact on bacterial communities (P<0.05). Antibiotics mainly promote defense- and signal transduction-related functions, and inhibit the metabolic activity of bacterial communities. However, the impact of antibiotics on bacterial diversity, community structure, and potential metabolic function in the three urban lakes was less than that of environmental factors. These results help to clarify the mechanism and degree of impact of different interference factors (environmental factors, conventional pollutants, and antibiotics) on bacterial communities in the water environment and are important for the management of urban landscape lake water environments.

Promoting short-chain fatty acids production from sewage sludge via acidogenic fermentation: Optimized operation factors and iron-based persulfate activation system.

Promoting short-chain fatty acids (SCFAs) production and ensuring the stability of SCFAs-producing process are becoming the two major issues for popularizing the acidogenic fermentation (AF). The key controlling operating and influencing factors during anaerobic fermentation process were thoroughly reviewed to facilitate better process performance prediction and to optimize the process control of SCFAs promotion. The wide utilization of iron salt flocculants during wastewater treatment could result in iron accumulating in sewage sludge which influenced AF performance. Additionally, appropriate ferric chloride (FC) could promote the SCFAs accumulation, while poly ferric sulfate (PFS) inhibited the bioprocess. Iron/persulfate (PS) system was proved to effectively enhance the SCFAs production while mechanism analysis revealed that the strong oxidizing radicals remarkably enhanced the solubilization and hydrolysis. Moreover, the changes of oxidation-reduction potential (ORP) and pH caused by iron/PS system exhibited more negative effects on the methanogens, comparing to the acidogenic bacteria. Furthermore, performance and mechanisms of different iron species-activating PS, organic chelating agents and iron-rich biochar derived from sewage sludge were also elucidated to extend and strengthen understanding of the iron/PS system for enhancing SCFAs production. Considering the large amount of generated Fe-sludge and the multiple benefits of iron activating PS system, carbon neutral wastewater treatment plants (WWTPs) were proposed with Fe-sludge as a promising recycling composite to improve AF performance. It is expected that this review can deepen the knowledge of optimizing AF process and improving the iron/PS system for enhancing SCFAs production and provide useful insights to researchers in this field.

Temporal and Spatial Variation Characteristics and Influencing Factors of Bacterial Community in Urban Landscape Lakes.

Urban landscape lakes are closely related to human activity, but there are limited studies on their bacterial community characteristics and risks to human health. In this study, four different types of urban landscape lakes in Xi'an were selected, and the bacterial community structures in different seasons were analyzed by Illumina Nova high-throughput sequencing technology. Seasonal variations in bacterial communities were analyzed by linear discriminant analysis, STAMP difference analysis, and nonmetric multidimensional scaling. Redundancy analysis was used to investigate the influencing factors. Furthermore, the metabolic functions of bacterial communities were predicted by Tax4Fun. There were clear seasonal differences in the α-diversity of bacteria, with bacterial diversity being higher in winter than in summer in the four urban landscape lakes, and the diversity of different water sources was different; the distributions of Proteobacteria, Actinobacteria, Chloroflexi, and Verrucomicrobia had significant seasonal differences; and the dominant bacteria at the genus level had obvious temporal and spatial differences. Furthermore, a variety of environmental factors had an impact on bacterial communities, and temperature, DO, and nitrogen were the primary factors affecting the seasonal variation in bacteria. There are also significant seasonal differences in the metabolic functions of bacterial communities. These results are helpful for understanding the current status of bacteria in the aquatic environments of such urban landscape lakes.

[Bacterial Community Structure and the Prediction of Metabolic Function in Landscape Lake Water in Xi'an].

The study of bacterial community diversity and metabolic function in lake water is of great significance to the healthy development of the urban landscape lake water environment. In this study, Hancheng Lake, Nanhu Lake, Xingqing Lake, and Taohuatan Lake were selected as the study area. Illumina Nova high-throughput sequencing technology was used to study the composition and structure of bacterial communities in four different types of lakes. The correlation between bacterial communities and environmental factors was analyzed using the RDA method. Tax4Fun was used to predict the metabolic function of bacterial communities. The results showed that the diversity of bacterial communities was different in different lakes. The α diversity of Taohuatan Lake was the highest, and that of Xingqing Lake was the lowest. The bacterial community structure of the same lake had a trend of aggregation. The dominant phyla of bacteria in the four lakes were similar, mainly Proteobacteria, Bacteroidetes, and Actinobacteria. The difference was only in the proportion of bacteria. Additionally, the distribution of bacterial communities at the genus level in the four lakes was quite different. The physical and chemical properties of lakes were significantly correlated with bacterial community, and the most critical factor was nitrogen and phosphorus nutrients(P<0.05). Tax4Fun function prediction showed that the metabolic function of bacterial communities in the four lakes was similar, and the relative abundance of amino acid metabolism and carbohydrate metabolism was the highest. In addition, the potential drug-resistant bacterial pollution and the possibility of human infectious diseases were higher. These results are helpful for understanding the current situation of bacteria in urban lakes in Xi'an and providing a theoretical basis for the management and sustainable development of urban lakes.

In vitro toxicity assessment of haloacetamides via a toxicogenomics assay.

It is important to study the stress effects and mechanisms of haloacetamide (HAcAm) disinfection byproducts to reveal their health hazards. In this context, toxicological g was applied to evaluate the effects of four HAcAms, revealing the status of gene expression on Escherichia coli in different stress response types (oxidative, protein, membrane, general, DNA). This study revealed that the main toxic action modes of these HAcAms were general and membrane stresses by high-resolution, real-time gene expression profiling combined with clustering analysis. The results of time-gene evaluation showed that the presence of chloroacetamide (CAcAm) and bromoacetamide (BAcAm) generated more reactive oxygen species, thus activating oxidative stress. Trichloroacetamide (tCAcAm) induced altered expression of glutathione marker genes and membrane stress-related genes, and iodoacetamide (IAcAm) caused severe DNA damage by damaging DNA strands and individual nucleotides mainly through damage to nucleic acids and bases. Furthermore, quantitative structure-activity relationship (QSAR) modelling results indicated that the biological activities of HAcAms were related to their quantum chemical and topological properties.

Influence of Aeration Pipe Length on Oxygen Mass Transfer Efficiency in Terms of Bubble Motion Flow Field.

Improving the gas-liquid mass transfer efficiency in microporous aeration technology is the key to strengthening the restoration effect of black and odorous water bodies. However, the effect of bubble motion characteristics on oxygen mass transfer has not been systematically studied, which limits the efficient and economical application of microporous aeration remediation technology in black and odorous water. The influence under different aeration pipe lengths was analyzed for oxygen mass transfer and bubble movement in microporous aeration technology. The aeration pipe length (0.1-0.5 m) was positively correlated (R = 1.000, R = 0.997) with the number of bubbles and the specific surface area of bubbles and negatively correlated with the time-average velocity of bubbles and Sauter average diameter (R = -0.999, R = -0.997). Moreover, the increase in pipe length weakened the disturbance intensity of plume to water body. The results of oxygen mass transfer showed that the oxygen mass transfer coefficient (K L a) and oxygen utilization rate (E A) increased (K L a from 1.96 to 4.57 h-1, E A from 6.47 to 15.07%) with the increase of pipe length, which was significantly positively correlated (R = 0.985, R = 0.969) with the number of bubbles and bubble specific surface area (S b). This study provided theoretical parameters for the mechanism of oxygen mass transfer during microporous aeration.

Coupling anammox with denitrification in a full-scale combined biological nitrogen removal process for swine wastewater treatment.

In order to enhance nitrogen removal through anammox process in the full-scale swine wastewater treatment plant, an innovative regulation strategy of nitrate-based carbon dosage and intermittent aeration was developed to apply the combined biological nitrogen removal process in a full scale anaerobic-anoxic-oxic (A2/O) system. TN removal efficiency reached at 65.5 ± 6.0% in Phase 1 with decreasing external carbon dosage in influent due to the reduction of return nitrate concentration, and it increased to 83.5 ± 6.7% when intermittent aeration was adopted in oxic zone and external carbon source was stopped adding into influent in Phase 2. As a result, the energy consumption for the swine wastewater treatment decreased from 1.93 to 0.9 kW h/m3 and 4.18 to 2.57 kW h/kg N, respectively. Microbial community analysis revealed that the average abundances of Candidatus Brocadia increased from 0.76% to 2.43% and removal of TN through anammox increased from 39% to 77%.

Characteristics of oxygen mass transfer and its impact on pollutant removal performance and microbial community structure in an aerobic fluidized bed biofilm reactor for treatment of municipal wastewater.

A laboratory-scale aerobic fluidized bed biofilm reactor (AFBBR) was established to evaluate the oxygen mass transfer (OMT) process and its impact on municipal wastewater treatment performance. Aeration rates had different effects on the OMT of the wastewater and biofilm. In the wastewater, oxygenation performance, oxygen uptake rate (OUR), and volumetric OMT coefficient (kLa) improved under high aeration rates. However, within the biofilm, the OMT process under the aeration rate of 0.096 L/(min·L) were higher than under other conditions [0.064 L/(min·L) and 0.128 L/(min·L)]. The denitrifying bacteria (DNB) abundance under the aeration rate of 0.096 L/(min·L) were improved so that total nitrogen (TN, 66.98 ± 4.23%) and ammonia nitrogen (NH4+-N, 74.70 ± 2.30%) removal were higher than those under other aeration conditions. These results showed that suitable aeration could improve wastewater treatment efficiency through changing the OMT process and microbial community structure.

Occurrence of antibiotics in rural drinking water and related human health risk assessment.

Antibiotic residues in drinking water can have a negative impact on both human and environmental health. However, drinking water purification processes employed in rural areas are often less complicated than those used in urban areas. The occurrence of antibiotic residues in rural drinking water and their potential effects on residents' health remains to be established. In this study, we measured antibiotic levels in rural drinking water using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and evaluated the associated health risks based on Chinese population exposure parameters. Twenty-three antibiotics were detected in drinking water samples, of which fluoroquinolones and macrolides were the most common. The type and concentration of antibiotics in drinking water were affected both by the quality of the water source and by the water purification process used. The health risks associated with antibiotics in drinking water were within acceptable levels and likely to have little impact on human health. Of the antibiotics detected, salinomycin presented the greatest risk to human health. These findings can help to play a role in devising strategies to ensure drinking water safety.

In situ startup of a full-scale combined partial nitritation and anammox process treating swine digestate by regulation of nitrite and dissolved oxygen.

A challenge during the startup of the combined partial nitritation and anammox process is how to balance dissolved oxygen control and nitrite accumulation for converting partial nitritation into anammox, maintaining stable partial nitritation and promoting growth of anammox bacteria. An innovative regulation strategy of nitrite dosing and dissolved oxygen control in this study was developed to achieve the rapid startup of a full-scale combined partial nitritation and anammox reactor within 77 days and the total nitrogen removal rate of reactor was 0.097 kg N/kgMLSS·d-1, and the activity and gene copy concentration of anammox bacteria reached 0.307 kg N/kgMLVSS·d-1 and 7.79 × 109 copies/gMLVSS, respectively. Microbial community analysis revealed that Candidatus_Kuenenia and Nitrosomonas were the dominant nitrogen transformation bacteria with an abundance of 2.49% and 14.86%, respectively. This study offers a new method for rapid startup and spreading application of the full-scale anammox process.

[Environmental Response and Ecological Function Prediction of Aquatic Bacterial Communities in the Weihe River Basin].

The diversity of bacterial communities and their metabolic function in the waters of the Weihe River Basin are of great significance for water pollution remediation, ecological restoration, and water quality assessment. Illumina MiSeq high-throughput sequencing technology was applied to study the bacterial community distribution characteristics after the comprehensive treatment of the Shaanxi part of the Weihe River Basin. Furthermore, the correlation between the bacterial communities and environmental factors was analyzed by redundancy analysis (RDA), and the PICRUSt method was adopted to evaluate the ecological function of the bacterial communities. The results showed that Proteobacteria, Actinobacteria, Cyanobacteria, and Bacteroidetes were the main bacterial communities in the water, accounting for 85% of the total microbial community. Additionally, these bacteria showed a significant positive correlation (P=0.02, <0.05) with the TP, NO2--N, NO3--N, and TN. The bacteria community richness of water samples collected in Zaohe River was the lowest of all samples, while which in the downstream of the junction of Bahe river and Weihe river was the highest. In addition, water in the Weihe River Basin had great impact on the endocrine systems of aquatic organisms, and also had a possibility of infectious diseases for humans. Our research provides a theoretical basis for the safe and sustainable development of the water environment in the Weihe River Basin.

Characteristics of the extracellular polymeric substance composition in an up-flow biological aerated filter reactor: The impacts of different aeration rates and filter medium heights.

In this study, the compositional characteristics of extracellular polymeric substances (EPS) were systematically explored to reveal their relationship with microbial community under different conditions in an up-flow biological aerated filter reactor. The aeration rates had a significant positive correlation (0.898 ≤ R ≤ 0.979) with the tightly bound (TB)-EPS contents, but basically showed an opposite trend (R < -0.631) with the loosely bound (LB)-EPS. Moreover, the filter medium heights also affected EPS distribution. The microbial biofilm produced more LB-EPS and TB-EPS to withdraw from the extreme environment. Five fluorescent substances were identified in the EPS by EEM-PARAFAC modeling; namely, two protein-like components (protein-like C1 and tryptophan-like C2) and three humic-like components (UVA marine humic-like C3, hydrophobic humic acid-like C4, and humic acid-like C5). Under different conditions, the relative abundance of Proteobacteria and Nitrospirae had a significant positive correlation with C5 and C4, respectively. These results demonstrated that microbial community distribution could affect EPS composition.

A spectroscopic and theoretical investigation of interaction mechanisms of tetracycline and polystyrene nanospheres under different conditions.

Interaction mechanisms of tetracycline (TC, as a typical antibiotic) on polystyrene microsphere (PSs, as a typical nanoplastic) were conducted by the batch, spectroscopic and theoretical techniques. The batch results showed that Na+ and K+ had no obvious effects on TC adsorption towards PSs, whereas Mg2+ significantly inhibited TC adsorption at pH > 5.0 due to its induced aggregations of PSs. The maximum TC adsorption capacity of PSs in the presence of humic acid (50.99 mg/g) was higher than that of PSs (44.77 mg/g) at pH 6.0. The highly effective adsorption was attributed to electrostatic attraction, π-π interaction and hydrophobic effect, which was determined by FT-IR and XPS analysis. According to DFT (density functional theory) calculations, the adsorption energy of TC/TC+ on PSs (1.52 eV) was significantly higher than that of negative TC- (0.57 eV), whereas minimum distance of TC on PSs (3.684 Å) was shorter than that of TC- on PSs (3.988 Å). The results of theoretical calculations indicated that TC was more preferably adsorbed on PSs with more stable configuration compared to TC-. These findings indicated that PSs can be used as a promising adsorbent for immobilization and pre-concentration of TC from aqueous solutions.

Use of acupuncture in the USA: changes over a decade (2002-2012).

BACKGROUND: The use of acupuncture has gained popularity in the USA. The number of acupuncture users and licensed acupuncturists increased by 50% and 100%, respectively, between 2002 and 2012, coinciding with increasing acknowledgement of the importance and efficacy of acupuncture over this time period. METHODS: This paper presents new findings from the complementary health approaches section of the 2012 National Health Interview Survey (n=33 373 respondents). In particular, data on the use of acupuncture and user characteristics were compared against data collected from an earlier survey in 2002. Statistical analyses included weighted distribution, logistical regression and Pearson's χ2 tests. RESULTS: The profile of the most common acupuncture users comprised the following sociodemographics age 41-65 years (47.4%); female gender (69.6%); and non-Hispanic (85.3%) and/or white (78.1%) ethnicity. Respondents also tended to be US citizens (92.1%) with some college education (57.1%) and in very good to excellent health (60.8%). The proportion of respondents using acupuncture for treatment of a specific health problem, as opposed to promotion of general wellness, was 84.7% in 2002 and 55.3% in 2012. CONCLUSIONS: Our data suggest a growing development of acupuncture in the USA. We anticipate that the findings of our analysis of the changes in acupuncture use over the 10-year period from 2002 to 2012 will provide information for users, acupuncturists, researchers and the general public to help better understand the status of acupuncture and reasons for its usage, and to anticipate future trends for acupuncture use in the USA.

Sustained high prevalence of viral hepatitis and sexually transmissible infections among female sex workers in China: a systematic review and meta-analysis.

BACKGROUND: The 1980's economic boom has been associated with a rapid expansion of China's sex industry over the past three decades. Consequently, the spread of sexually transmitted infections (STIs) and hepatitis infections among female sex workers (FSW) has become an important public health issue in China. This study identifies prevalence and risks of hepatitis and STIs in Chinese FSWs. METHOD: Four electronic databases were searched for Chinese and English language peer-reviewed studies conducted between 01/2000-12/2011 that reported prevalence of hepatitis and STIs (excluding HIV) among Chinese FSW. Following the PRISMA guidelines, meta-analysis was used to estimate pooled prevalence and 95% confidence intervals for each infection. RESULT: Three hundred and thirty nine articles (34 in English and 305 in Chinese) investigating 603,647 FSWs in 29 Chinese provinces were included in this review. Over the period 2000-2011, the seroprevalence of active hepatitis B and hepatitis C among FSW were 10.7% (7.3-15.5%) and 1.0% (0.7-1.3%), respectively. The most prevalent STI was human papillomavirus (HPV, 27.0% [10.1-55.1%]), followed by herpes simplex virus-2 (HSV-2, 15.8% [11.7-20.9%]), chlamydia (13.7% [12.1-15.4%]), gonorrhoea (6.1% [5.3-7.0%]), syphilis (5.2% [4.8-5.7%]), genital warts (3.3% [2.5-4.2%]) and Trichomonas vaginitis (2.1% [1.5-24.2%]). Disease burden of both hepatitis and STI among FSW were concentrated in South Central and Southwest China. In particular, chlamydia and syphilis demonstrated a significant declining trend during the studied period (P < 0.05). Compared with the general Chinese population, FSW had significantly higher prevalence of all STIs except Trichomonas vaginitis. Further, compared to the general FSW population, HIV-positive FSW had significantly higher prevalence of syphilis, chlamydia, HSV-2 and Trichomonas vaginitis. CONCLUSION: Prevalence of hepatitis and STIs remained high and mostly stable among Chinese FSW over the period of 2000-2011. Targeted STI and hepatitis surveillance and interventions should be strengthened among Chinese FSWs, especially those who are HIV-positive.

Factors associated with women's entry into the sex industry: findings from interviews conducted with female sex workers in Chinese detention centres.

BACKGROUND: To date, limited research has been conducted to identify the personal and contextual factors that contribute to women's entry into the sex industry in China. METHODS: The reasons for and factors associated with voluntary entry into the sex industry were explored through in-depth interviews conducted with 38 Chinese women who were held in detention centres for selling sex. RESULTS: Women's personal accounts reveal that entry into sex work is influenced by life aspirations, family responsibilities and social connections, which facilitate mobility to a new urban environment in which they encounter opportunities and challenges. Findings highlight the complex interactions between individual and contextual factors in relation to women's entry into sex work. CONCLUSIONS: In a rapidly developing country such as China, entry into sex work may appeal to women of low socioeconomic status, particularly young women who have recently migrated to urban areas. For members of this mobile and relatively disadvantaged population, comprehensive social services and support are urgently needed.