Wastewater irrigation increases the abundance of potentially harmful gammaproteobacteria in soils in Mezquital Valley, Mexico. - Related Documents




#
Rank
Similarity
Title + Abs.
Year
PMID
012345
530301.0000Wastewater irrigation increases the abundance of potentially harmful gammaproteobacteria in soils in Mezquital Valley, Mexico. Wastewater contains large amounts of pharmaceuticals, pathogens, and antimicrobial resistance determinants. Only a little is known about the dissemination of resistance determinants and changes in soil microbial communities affected by wastewater irrigation. Community DNAs from Mezquital Valley soils under irrigation with untreated wastewater for 0 to 100 years were analyzed by quantitative real-time PCR for the presence of sul genes, encoding resistance to sulfonamides. Amplicon sequencing of bacterial 16S rRNA genes from community DNAs from soils irrigated for 0, 8, 10, 85, and 100 years was performed and revealed a 14% increase of the relative abundance of Proteobacteria in rainy season soils and a 26.7% increase in dry season soils for soils irrigated for 100 years with wastewater. In particular, Gammaproteobacteria, including potential pathogens, such as Pseudomonas, Stenotrophomonas, and Acinetobacter spp., were found in wastewater-irrigated fields. 16S rRNA gene sequencing of 96 isolates from soils irrigated with wastewater for 100 years (48 from dry and 48 from rainy season soils) revealed that 46% were affiliated with the Gammaproteobacteria (mainly potentially pathogenic Stenotrophomonas strains) and 50% with the Bacilli, whereas all 96 isolates from rain-fed soils (48 from dry and 48 from rainy season soils) were affiliated with the Bacilli. Up to six types of antibiotic resistance were found in isolates from wastewater-irrigated soils; sulfamethoxazole resistance was the most abundant (33.3% of the isolates), followed by oxacillin resistance (21.9% of the isolates). In summary, we detected an increase of potentially harmful bacteria and a larger incidence of resistance determinants in wastewater-irrigated soils, which might result in health risks for farm workers and consumers of wastewater-irrigated crops.201424951788
530710.9999Increased Antimicrobial and Multidrug Resistance Downstream of Wastewater Treatment Plants in an Urban Watershed. Development and spread of antimicrobial resistance (AMR) and multidrug resistance (MDR) through propagation of antibiotic resistance genes (ARG) in various environments is a global emerging public health concern. The role of wastewater treatment plants (WWTPs) as hot spots for the dissemination of AMR and MDR has been widely pointed out by the scientific community. In this study, we collected surface water samples from sites upstream and downstream of two WWTP discharge points in an urban watershed in the Bryan-College Station (BCS), Texas area, over a period of nine months. E. coli isolates were tested for resistance to ampicillin, tetracycline, sulfamethoxazole, ciprofloxacin, cephalothin, cefoperazone, gentamycin, and imipenem using the Kirby-Bauer disc diffusion method. Antimicrobial resistant heterotrophic bacteria were cultured on R2A media amended with ampicillin, ciprofloxacin, tetracycline, and sulfamethoxazole for analyzing heterotrophic bacteria capable of growth on antibiotic-containing media. In addition, quantitative real-time polymerase chain reaction (qPCR) method was used to measure eight ARG - tetA, tetW, aacA, ampC, mecA, ermA, blaTEM, and intI1 in the surface water collected at each time point. Significant associations (p < 0.05) were observed between the locations of sampling sites relative to WWTP discharge points and the rate of E. coli isolate resistance to tetracycline, ampicillin, cefoperazone, ciprofloxacin, and sulfamethoxazole together with an increased rate of isolate MDR. The abundance of antibiotic-resistant heterotrophs was significantly greater (p < 0.05) downstream of WWTPs compared to upstream locations for all tested antibiotics. Consistent with the results from the culture-based methods, the concentrations of all ARG were substantially higher in the downstream sites compared to the upstream sites, particularly in the site immediately downstream of the WWTP effluent discharges (except mecA). In addition, the Class I integron (intI1) genes were detected in high amounts at all sites and all sampling points, and were about ∼20 times higher in the downstream sites (2.5 × 10(7) copies/100 mL surface water) compared to the upstream sites (1.2 × 10(6) copies/100 mL surface water). Results suggest that the treated WWTP effluent discharges into surface waters can potentially contribute to the occurrence and prevalence of AMR in urban watersheds. In addition to detecting increased ARG in the downstream sites by qPCR, findings from this study also report an increase in viable AMR (HPC) and MDR (E. coli) in these sites. This data will benefit establishment of improved environmental regulations and practices to help manage AMR/MDR and ARG discharges into the environment, and to develop mitigation strategies and effective treatment of wastewater.202134108949
535820.9999Abundance of antibiotics, antibiotic resistance genes and bacterial community composition in wastewater effluents from different Romanian hospitals. Antimicrobial resistance represents a growing and significant public health threat, which requires a global response to develop effective strategies and mitigate the emergence and spread of this phenomenon in clinical and environmental settings. We investigated, therefore, the occurrence and abundance of several antibiotics and antibiotic resistance genes (ARGs), as well as bacterial community composition in wastewater effluents from different hospitals located in the Cluj County, Romania. Antibiotic concentrations ranged between 3.67 and 53.05 μg L(-1), and the most abundant antibiotic classes were β-lactams, glycopeptides, and trimethoprim. Among the ARGs detected, 14 genes confer resistance to β-lactams, aminoglycosides, chloramphenicol, macrolide-lincosamide-streptogramin B (MLSB) antibiotics, sulfonamides, and tetracyclines. Genes encoding quaternary ammonium resistance and a transposon-related element were also detected. The sulI and qacEΔ1 genes, which confer resistance to sulfonamides and quaternary ammonium, had the highest relative abundance with values ranging from 5.33 × 10(-2) to 1.94 × 10(-1) and 1.94 × 10(-2) to 4.89 × 10(-2) copies/16 rRNA gene copies, respectively. The dominant phyla detected in the hospital wastewater samples were Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. Among selected hospitals, one of them applied an activated sludge and chlorine disinfection process before releasing the effluent to the municipal collector. This conventional wastewater treatment showed moderate removal efficiency of the studied pollutants, with a 55-81% decrease in antibiotic concentrations, 1-3 order of magnitude lower relative abundance of ARGs, but with a slight increase of some potentially pathogenic bacteria. Given this, hospital wastewaters (raw or treated) may contribute to the spread of these emerging pollutants in the receiving environments. To the best of our knowledge, this study quantified for the first time the abundance of antibiotics and ARGs in wastewater effluents from different Romanian hospitals.201728347610
536330.9999Irrigation Ponds as Sources of Antimicrobial-Resistant Bacteria in Agricultural Areas with Intensive Use of Poultry Litter. Poultry litter is widely used worldwide as an organic fertilizer in agriculture. However, poultry litter may contain high concentrations of antibiotics and/or antimicrobial-resistant bacteria (ARB), which can be mobilized through soil erosion to water bodies, contributing to the spread of antimicrobial resistance genes (ARGs) in the environment. To better comprehend this kind of mobilization, the bacterial communities of four ponds used for irrigation in agricultural and poultry production areas were determined in two periods of the year: at the beginning (low volume of rainfall) and at the end of the rainy season (high volume of rainfall). 16S rRNA gene sequencing revealed not only significantly different bacterial community structures and compositions among the four ponds but also between the samplings. When the DNA obtained from the water samples was PCR amplified using primers for ARGs, those encoding integrases (intI1) and resistance to sulfonamides (sul1 and sul2) and β-lactams (bla(GES), bla(TEM) and bla(SHV)) were detected in three ponds. Moreover, bacterial strains were isolated from CHROMagar plates supplemented with sulfamethoxazole, ceftriaxone or ciprofloxacin and identified as belonging to clinically important Enterobacteriaceae. The results presented here indicate a potential risk of spreading ARB through water resources in agricultural areas with extensive fertilization with poultry litter.202236421294
530440.9998Water metagenomic analysis reveals low bacterial diversity and the presence of antimicrobial residues and resistance genes in a river containing wastewater from backyard aquacultures in the Mekong Delta, Vietnam. The environmental pathways for the dissemination of antibiotic resistance have recently received increased attention. Aquatic environments act as reservoirs or sources of antimicrobial-resistant bacteria, antimicrobial residues, and antimicrobial resistance genes (ARGs). Therefore, it is imperative to identify the role of polluted water in the dissemination of antimicrobial resistance. The aim of this study was to evaluate the antimicrobial residues, ARGs, and microbiota in the freshwater systems of the Mekong Delta. We selected 12 freshwater sites from aquacultures and rivers in Can Tho, Vietnam and analyzed them for 45 antimicrobial residues and 8 ARGs by LC/MS/MS and real-time PCR, respectively. A 16S rDNA-based metagenomic analysis was conducted to characterize the water microbiota. Residues of sulfamethoxazole (10/12) and sulfadimidine (7/12) were widely detected, together with the sulfa-resistance genes sul1 (11/12) and sul2 (9/12). Additionally, sulfamethoxazole residues and the β-lactamase-resistance gene bla(CTX-M-1) were detected in eight freshwater systems (8/12), suggesting that these freshwater systems may have been polluted by human activity. The metagenomic analysis showed that all the tested freshwater systems contained the phyla Proteobacteria, Actinobacteria, and Bacteroidetes, representing 64% of the total microbiota. Moreover, the Cai Rang River site (Ri-E), which is located at the merge point of wastewaters from backyard-based aquacultures, contained the genera Polynucleobacter, Variovorax, and Limnohabitans, representing more than 78.4% of the total microbiota. Bacterial diversity analysis showed that the Ri-E exhibited the lowest diversity compared with other regions. Principal coordinate analysis showed that the differences among water microbiotas in backyard-based aquacultures could be explained by the farmers' aquaculture techniques. In conclusion, this study demonstrated a collapse of bacterial diversity at the merge point of wastewaters from backyard-based aquacultures in the Mekong Delta.201728062224
537350.9998Impact of soil supplemented with pig manure on the abundance of antibiotic resistant bacteria and their associated genes. This study was conducted to evaluate the abundance of antibiotic resistant bacteria and their resistance genes from agriculture soil supplemented with pig manure. Uncultivable soil sample was supplemented with pig manure samples under microcosm experimental conditions and plated on Luria-Bertani (LB) agar incorporated with commercial antibiotics. The supplementation of soil with 15% pig manure resulted in the highest increase in the population of antibiotic resistant bacteria (ARB)/multiple antibiotic resistant bacteria (MARB). Seven genera that included Pseudomonas, Escherichia, Providencia, Salmonella, Bacillus, Alcaligenes and Paenalcaligenes were the cultivable ARB identified. A total of ten antibiotic resistant bacteria genes (ARGs) frequently used in clinical or veterinary settings and two mobile genetic elements (MGEs) (Class 1 and Class 2 integrons) were detected. Eight heavy metal, copper, cadmium, chromium, manganese, lead, zinc, iron, and cobalt were found in all of the manure samples at different concentrations. Tetracycline resistance genes were widely distributed with prevalence of 50%, while aminoglycoside and quinolone-resistance gene had 16% and 13%, respectively. Eighteen ARB isolates carried more than two ARGs in their genome. Class 1 integron was detected among all the 18 ARB with prevalence of 90-100%, while Class 2 integron was detected among 11 ARB. The two classes of integron were found among 10 ARB. Undoubtedly, pig manure collected from farms in Akure metropolis are rich in ARB and their abundance might play a vital role in the dissemination of resistance genes among clinically-relevant pathogens.202337308603
532360.9998Monitoring and assessing the impact of wastewater treatment on release of both antibiotic-resistant bacteria and their typical genes in a Chinese municipal wastewater treatment plant. Wastewater treatment plants (WWTPs) are important hotspots for the spread of antibiotic resistance. However, the release and impact factors of both antibiotic resistant bacteria and the relevant genes over long periods in WWTPs have rarely been investigated. In this study, the fate of bacteria and genes resistant to six commonly used antibiotics was assessed over a whole year. In WWTP effluent and biosolids, a high prevalence of heterotrophic bacteria resistant to vancomycin, cephalexin, sulfadiazine and erythromycin were detected, each with a proportion of over 30%. The corresponding genes (vanA, ampC, sulI and ereA) were all detected in proportions of (2.2 ± 0.8) × 10(-10), (6.2 ± 3.2) × 10(-9), (1.2 ± 0.8) × 10(-7) and (7.6 ± 4.8) × 10(-8), respectively, in the effluent. The sampling season imposed considerable influence on the release of all ARB. High release loads of most ARB were detected in the spring, while low release loads were generally found in the winter. In comparison, the ARG loads changed only slightly over various seasons. No statistical relevance was found between all ARB abundances and their corresponding genes over the long-term investigation period. This inconsistent behavior indicates that bacteria and genes should both be considered when exploring resistance characteristics in wastewater. A redundancy analysis was adopted to assess the impact of wastewater quality and operational conditions on antibiotic resistance. The results indicated that most ARB and ARG proportions were positively related to the COD and turbidity of the raw sewage, while negatively related to those of the effluent. DO and temperature exhibited strong negative relevance to most ARB prevalence.201424927359
531070.9998Antimicrobial-Resistant Bacterial Populations and Antimicrobial Resistance Genes Obtained from Environments Impacted by Livestock and Municipal Waste. This study compared the populations of antimicrobial-resistant bacteria and the repertoire of antimicrobial resistance genes in four environments: effluent of three municipal wastewater treatment facilities, three cattle feedlot runoff catchment ponds, three swine waste lagoons, and two "low impact" environments (an urban lake and a relict prairie). Multiple liquid and solid samples were collected from each environment. The prevalences and concentrations of antimicrobial-resistant (AMR) Gram-negative (Escherichia coli and Salmonella enterica) and Gram-positive (enterococci) bacteria were determined from individual samples (n = 174). The prevalences of 84 antimicrobial resistance genes in metagenomic DNA isolated from samples pooled (n = 44) by collection date, location, and sample type were determined. The prevalences and concentrations of AMR E. coli and Salmonella were similar among the livestock and municipal sample sources. The levels of erythromycin-resistant enterococci were significantly higher in liquid samples from cattle catchment ponds and swine waste lagoons than in liquid samples from municipal wastewater treatment facilities, but solid samples from these environments did not differ significantly. Similarly, trimethoprim/sulfamethoxazole-resistant E. coli concentrations were significantly higher in swine liquid than in municipal liquid samples, but there was no difference in solid samples. Multivariate analysis of the distribution of antimicrobial resistance genes using principal coordinate analysis showed distinct clustering of samples with livestock (cattle and swine), low impact environment and municipal samples forming three separate clusters. The numbers of class A beta-lactamase, class C beta-lactamase, and fluoroquinolone resistance genes detected were significantly higher (P < 0.05) in municipal samples than in cattle runoff or swine lagoon samples. In conclusion, we report that AMR is a very widespread phenomenon and that similar prevalences and concentrations of antimicrobial-resistant bacteria and antimicrobial resistance genes exist in cattle, human, and swine waste streams, but a higher diversity of antimicrobial resistance genes are present in treated human waste discharged from municipal wastewater treatment plants than in livestock environments.201526197056
534480.9998Seasonal dynamics of tetracycline resistance gene transport in the Sumas River agricultural watershed of British Columbia, Canada. Environmental transport of contaminants that can influence the development of antibiotic resistance in bacteria is an important concern in the management of ecological and human health risks. Agricultural regions are locales where practices linked to food crop and livestock production can introduce contaminants that could alter the selective pressures for the development of antibiotic resistance in microbiota. This is important in regions where the use of animal manure or municipal biosolids as waste and/or fertilizer could influence selection for antibiotic resistance in pathogenic bacterial species. To investigate the environmental transport of contaminants that could lead to the development of antibiotic resistance in bacteria, a watershed with one of the highest levels of intensity of agricultural activity in Canada was studied; the Sumas River located 60 km east of Vancouver, British Columbia. This two-year assessment monitored four selected tetracycline resistance genes (tet(O), tet(M), tet(Q), tet(W)) and water quality parameters (temperature, specific conductivity, turbidity, suspended solids, nitrate, phosphate and chloride) at eight locations across the watershed. The tetracycline resistance genes (Tc(r)) abundances in the Sumas River network ranged between 1.47 × 10(2) and 3.49 × 10(4) copies/mL and ranged between 2.3 and 6.9 copies/mL in a control stream (located far from agricultural activities) for the duration of the study. Further, Tc(r) abundances that were detected in the wet season months ranged between 1.3 × 10(3) and 2.29 × 10(4) copies/mL compared with dry season months (ranging between 0.6 and 31.2 copies/mL). Highest transport rates between 1.67 × 10(11) and 1.16 × 10(12) copies/s were observed in November 2005 during periods of high rainfall. The study showed that elevated concentrations of antibiotic resistance genes in the order of 10(2)-10(4) copies/mL can move through stream networks in an agricultural watershed but seasonal variations strongly influenced specific transport patterns of these genes.201829453178
712090.9998Impact of liquid hog manure applications on antibiotic resistance genes concentration in soil and drainage water in field crops. Agricultural practices such as manure applications could contribute to the spread of antibiotic resistance genes (ARGs) within the environment. Our objective was to assess the impact of certain fertilization methods (mineral or manure) and tillage practices (reduced or conventional) on the presence of ARGs and bacteria in soil and drainage water under wheat and grain corn crops. Targeted ARGs tet(T), sul1, and bla(CTX-M-1) in liquid hog manure, soil, and water samples were quantified by qPCR. Conventional PCR was used to detect mcr-1 and mcr-2. ARGs in control plots were detected despite the absence of manure, representing an environmental reservoir of resistant microorganisms. The manure application rate higher than 39 m(3)/ha increased tet(T) and sul1 gene concentrations in soil for more than 180 days. Tillage practices had no impact on ARG concentrations in soil and water samples. The bla(CTX-M-1) gene was only detected in seven water samples in 2016, but no link was established with the treatments. The mcr-1 and mcr-2 genes were not detected in all tested samples. This study demonstrated that tet(T) and sul1 gene concentrations increased in soil after liquid hog manure application as well as in drainage water in the next weeks.202032330390
5357100.9998Occurrence and diversity of antibiotic resistance in untreated hospital wastewater. Antibiotics, antibiotic-resistant bacteria (ARB), antibiotic-resistance genes (ARGs), and mobile genetic elements (MGEs) have been reported in many environments. However, the investigation of their occurrence and diversity in untreated hospital wastewater is still insufficient. High concentrations of antibiotic residues were found in hospital wastewater using solid-phase extraction and UPLC-MS/MS analysis. The concentrations of six of 14 antibiotics reached μg/L levels in the hospital wastewater, which is higher than reported in other aquatic environments. Results of high-throughput sequencing analysis indicated that sequences affiliated to genera Escherichia and Acinetobacter were the predominant in the cultivable multiple-antibiotic-resistant bacteria (CMARB) recovered from the wastewater of three hospitals in China, with compositions of 34%-74%. Notably, several genera containing clinically pathogenic or opportunistic CMARB (e.g., Escherichia, Acinetobacter, Aeromonas, Myroides, Enterococcus, Proteus, Pseudomonas, and Streptococcus) were detected at high relative abundances in the wastewaters of the three hospitals. High-capacity quantitative PCR showed that 131-139 unique ARGs of the 178 targeted genes were detected in the hospital wastewaters. The high prevalence of five MGEs and 12 ARGs was confirmed with qPCR, and some positive correlations between ARGs and MGEs were identified, such as between intI1 and qnrD, intI2 and sul3, intI3 and tetX, Tn916/Tn1545 and sul2, and ISCR1 and sul3. These results suggest that highly abundant antibiotic-resistant pathogens and highly mobile ARGs already exist in the human body, and that their release from hospitals without effective treatment poses high risks to environments and human health.201829054666
5301110.9998High levels of antibiotic resistance genes and opportunistic pathogenic bacteria indicators in urban wild bird feces. This study analyzed fresh feces from three common bird species that live in urban environments and interact with human communities. Antibiotic resistance genes (ARGs) encoding resistance to three major classes of antibiotics (i.e., tetracyclines, β-lactams, and sulfonamides) and the mobile genetic element integrase gene (intI1) were abundant (up to 10(9), 10(8), 10(9), and 10(10) copies/g dry feces for tetW, bla(TEM), sul1, and intI1, respectively), with relative concentrations surprisingly comparable to that in poultry and livestock that are occasionally fed antibiotics. Biomarkers for opportunistic pathogens were also abundant (up to 10(7) copies/g dry feces) and the dominant isolates (i.e., Enterococcus spp. and Pseudomonas aeruginosa) harbored both ARGs and virulence genes. ARGs in bird feces followed first-order attenuation with half-lives ranging from 1.3 to 11.1 days in impacted soil. Although residual antibiotics were detected in the feces, no significant correlation was observed between fecal antibiotic concentrations and ARG relative abundance. Thus, other unaccounted factors likely contributed selective pressure for ARG maintenance. These findings highlight the contribution of wild urban bird feces to the maintenance and dissemination of ARGs, and the associated health risks.202032663725
5348120.9998Characterization of microbial community and antibiotic resistome in intra urban water, Wenzhou China. The present study investigated the water quality index, microbial composition and antimicrobial resistance genes in urban water habitats. Combined chemicals testing, metagenomic analyses and qualitative PCR (qPCR) were conducted on 20 locations, including rivers from hospital surrounds (n = 7), community surrounds (n = 7), and natural wetlands (n = 6). Results showed that the indexes of total nitrogen, phosphorus, and ammonia nitrogen of hospital waters were 2-3 folds high than that of water from wetlands. Bioinformatics analysis revealed a total of 1,594 bacterial species from 479 genera from the three groups of water samples. The hospital-related samples had the greatest number of unique genera, followed by those from wetlands and communities. The hospital-related samples contained a large number of bacteria associated with the gut microbiome, including Alistipes, Prevotella, Klebsiella, Escherichia, Bacteroides, and Faecalibacterium, which were all significantly enriched compared to samples from the wetlands. Nevertheless, the wetland waters enriched bacteria from Nanopelagicus, Mycolicibacterium and Gemmatimonas, which are typically associated with aquatic environments. The presence of antimicrobial resistance genes (ARGs) that were associated with different species origins in each water sample was observed. The majority of ARGs from hospital-related samples were carried by bacteria from Acinetobacter, Aeromonas and various genera from Enterobacteriaceae, which each was associated with multiple ARGs. In contrast, the ARGs that were exclusively in samples from communities and wetlands were carried by species that encoded only 1 to 2 ARGs each and were not normally associated with human infections. The qPCR showed that water samples of hospital surrounds had higher concentrations of intI1 and antimicrobial resistance genes such as tetA, ermA, ermB, qnrB, sul1, sul2 and other beta-lactam genes. Further genes of functional metabolism reported that the enrichment of genes associated with the degradation/utilization of nitrate and organic phosphodiester were detected in water samples around hospitals and communities compared to those from wetlands. Finally, correlations between the water quality indicators and the number of ARGs were evaluated. The presence of total nitrogen, phosphorus, and ammonia nitrogen were significantly correlated with the presence of ermA and sul1. Furthermore, intI1 exhibited a significant correlation with ermB, sul1, and bla(SHV), indicating a prevalence of ARGs in urban water environments might be due to the integron intI1's diffusion-promoting effect. However, the high abundance of ARGs was limited to the waters around the hospital, and we did not observe the geographical transfer of ARGs along with the river flow. This may be related to water purifying capacity of natural riverine wetlands. Taken together, continued surveillance is required to assess the risk of bacterial horizontal transmission and its potential impact on public health in the current region.202337396356
5361130.9998Microbiome and Resistome in Poultry Litter-Fertilized and Unfertilized Agricultural Soils. Background: Poultry litter is the main waste of poultry farming and is widely used as an agricultural fertilizer. However, owing to the use of antimicrobials in animal production, it can accumulate antimicrobial residues, antimicrobial-resistant bacteria (ARB), and antimicrobial resistance genes (ARGs). This study aimed to evaluate the impact of poultry litter use on the microbiome and resistome of agricultural soils. Methods: Soil samples from fertilized and unfertilized plots were collected from two horticultural farms that intensively use poultry litter. Microbiome composition was assessed using 16S rRNA sequencing. A culture-dependent method was used to isolate resistant strains on CHROMagar plates supplemented with sulfamethoxazole or ciprofloxacin. ARGs and integrase-encoding genes were identified by PCR. Results: Microbiome analysis revealed significant differences in structure and composition between poultry litter-fertilized and unfertilized soils. Fertilized soils exhibited greater alpha diversity and richness. Bacillota, commonly found in the avian gastrointestinal tract, were more abundant in fertilized soils. A total of 62 resistant strains were isolated, and 23 clinically relevant strains harbored ARGs, including fluoroquinolone (qnrA and qnrB) and β-lactam (bla(GES), bla(TEM), and bla(SHV)) resistance genes. Class 1 and 2 integron-associated genes (intI1 and intI2) were also detected. Notably, the rare bla(GES) gene was detected in Bacillus sp. from unfertilized soil. Similarly, qnrA co-occurred with bla(SHV) in a Bosea sp. strain from unfertilized soil. Conclusions: These findings highlight the potential for ARB dissemination in agricultural environments, where ARB and ARGs, once introduced into soils, may spread by weathering and other environmental factors, complicating negative control selection in in situ studies.202540298506
5306140.9998Occurrence of tetracycline-resistant fecal coliforms and their resistance genes in an urban river impacted by municipal wastewater treatment plant discharges. Antibiotic resistance of fecal coliforms in an urban river poses great threats to both human health and the environment. To investigate the occurrence and distribution of antibiotic resistant bacteria in an urban river, water samples were collected from the Chanhe River in Xi'an, China. After membrane filtration of water samples, the tetracycline resistance rate of fecal coliforms and their resistance genes were detected by plating and polymerase chain reaction (PCR), respectively. We found that fecal coliforms were generally resistant to tetracycline and saw average resistance rates of 44.7%. The genes tetA and tetB were widely detected, and their positive rate was 60%-100% and 40%-90%, respectively. We found few strains containing tetC, tetK, tetQ and tetX, and we did not identify any strains containing tetG, tetM or tetO. The prevalence of tetA and tetB over other genes indicated that the main mechanism for resistance to tetracycline is by changes to the efflux pump. Our analysis of the types and proportion of tetracycline resistance genes in the Chanhe River at locations upstream and downstream of the urban center suggests that the increased number of tetracycline-resistant fecal coliforms and spatial variation of tetracycline resistance genes diversity were related to municipal wastewater treatment plant discharge.201525901852
5345150.9998Spread of antimicrobial resistance genes via pig manure from organic and conventional farms in the presence or absence of antibiotic use. AIMS: Antibiotic-resistant bacteria affect human and animal health. Hence, their environmental spread represents a potential hazard for mankind. Livestock farming is suspected to be a key factor for spreading antibiotic resistance; consumers expect organic farming to imply less environmental health risk. This study aimed to assess the role of manure from organic and conventional farms for spreading antimicrobial resistance (AMR) genes. METHODS AND RESULTS: AMR-genes-namely tet(A), tet(B), tet(M), sul2 and qacE/qacEΔ1 (potentially associated with multiresistance) were quantified by qPCR. Antimicrobial use during the study period was qualitatively assessed from official records in a binary mode (yes/no). Median concentrations were between 6.44 log copy-equivalents/g for tet(A) and 7.85 for tet(M) in organic liquid manure, and between 7.48 for tet(A) and 8.3 for sul2 in organic farmyard manure. In conventional manure, median concentrations were 6.67 log copy-equivalents/g for sul2, 6.89 for tet(A), 6.77 for tet(B) and 8.36 for tet(M). Integron-associated qac-genes reached median concentrations of 7.06 log copy-equivalents/g in organic liquid manure, 7.13 in conventional manure and 8.18 in organic farmyard manure. The use of tetracyclines or sulfonamides increased concentrations of tet(A) and tet(M), or of sul2, respectively. Comparing farms that did not apply tetracyclines during the study, the relative abundance of tet(A) and tet(M) was still higher for conventional piggeries than for organic ones. CONCLUSIONS: Relative abundances of AMR genes were higher in conventional farms, compared to organic ones. Antibiotic use was linked to the relative abundance of AMR-genes. However, due to the bacterial load, absolute concentrations of AMR-genes were comparable between fertilizers of organic and conventional farms. SIGNIFICANCE AND IMPACT OF STUDY: To our knowledge, this is the first absolute quantification of AMR-genes in manure from organic farms. Our study underlines the importance of long-term reduction in the use of antimicrobial agents in order to minimize antibiotic resistance.202235835564
5324160.9998Abundances of tetracycline, sulphonamide and beta-lactam antibiotic resistance genes in conventional wastewater treatment plants (WWTPs) with different waste load. Antibiotics and antibiotic resistant bacteria enter wastewater treatment plants (WWTPs), an environment where resistance genes can potentially spread and exchange between microbes. Several antibiotic resistance genes (ARGs) were quantified using qPCR in three WWTPs of decreasing capacity located in Helsinki, Tallinn, and Tartu, respectively: sulphonamide resistance genes (sul1 and sul2), tetracycline resistance genes (tetM and tetC), and resistance genes for extended spectrum beta-lactams (blaoxa-58, blashv-34, and blactx-m-32). To avoid inconsistencies among qPCR assays we normalised the ARG abundances with 16S rRNA gene abundances while assessing if the respective genes increased or decreased during treatment. ARGs were detected in most samples; sul1, sul2, and tetM were detected in all samples. Statistically significant differences (adjusted p<0.01) between the inflow and effluent were detected in only four cases. Effluent values for blaoxa-58 and tetC decreased in the two larger plants while tetM decreased in the medium-sized plant. Only blashv-34 increased in the effluent from the medium-sized plant. In all other cases the purification process caused no significant change in the relative abundance of resistance genes, while the raw abundances fell by several orders of magnitude. Standard water quality variables (biological oxygen demand, total phosphorus and nitrogen, etc.) were weakly related or unrelated to the relative abundance of resistance genes. Based on our results we conclude that there is neither considerable enrichment nor purification of antibiotic resistance genes in studied conventional WWTPs.201425084517
5295170.9998Occurrence of (fluoro)quinolones and (fluoro)quinolone resistance in soil receiving swine manure for 11 years. Because of the widespread use of antibiotics in animal breeding, the agricultural application of animal manure can lead to the introduction of antibiotics, antibiotic-resistant bacteria and antibiotic resistance genes to the soil and surrounding environment, which may pose a threat to public health. In this study, we investigated the status of (fluoro)quinolone (FQ) residues and FQ resistance levels in soil with and without receiving long-term swine manure. Six FQs (pipemidic acid, lomefloxacin, enrofloxacin, norfloxacin, ciprofloxacin, and ofloxacin) were only detected in manured soil, with individual concentrations ranging from below the detection limit to 27.2 μg kg(-1) and increasing with the increase in swine manure application rates. Higher load rates of swine manure yielded a higher number of ciprofloxacin-resistant (CIPr) bacteria after spreading. A total of 24 CIPr bacterial isolates were obtained from the tested soil, which belonged to four phyla (Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes) or were related to nine different genera. Only 18 isolates from manured soil were positive for five plasmid-mediated quinolone resistance (PMQR) genes (aac(6')-Ib-cr, qnrD, qepA, oqxA, and oqxB). To our knowledge, this study is the first to examine the occurrence of PMQR genes in FQ-resistant bacteria from the soil environment. A similar result was observed for the total DNA from soil, with the exception of aac(6')-Ib being detected in the control sample. The absolute and relative abundances of total PMQR genes also increased with fertilization quantity. Significant correlations were observed between FQ resistance levels and FQ concentrations. These results indicated that the agricultural application of swine manure led to FQ residues and enhanced FQ resistance. This investigation provides baseline data on FQ resistance profiles in soils receiving long-term swine manure.201526042895
5359180.9998Metagenomic insights into plasmid-mediated antimicrobial resistance in poultry slaughterhouse wastewater: antibiotics occurrence and genetic markers. Slaughterhouse wastewater represents important convergence and concentration points for antimicrobial residues, bacteria, and antibiotic resistance genes (ARG), which can promote antimicrobial resistance propagation in different environmental compartments. This study reports the assessment of the metaplasmidome-associated resistome in poultry slaughterhouse wastewater treated by biological processes, employing metagenomic sequencing. Antimicrobial residues from a wastewater treatment plant (WWTP) that treats poultry slaughterhouse influents and effluents were investigated through high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). Residues from the macrolide, sulfonamide, and fluoroquinolone classes were detected, the latter two persisting after the wastewater treatment. The genetic markers 16S rRNA rrs (bacterial community) and uidA (Escherichia coli) were investigated by RT-qPCR and the sul1 and int1 genes by qPCR. After treatment, the 16S rRNA rrs, uidA, sul1, and int1 markers exhibited reductions of 0.67, 1.07, 1.28, and 0.79 genes copies, respectively, with no statistical significance (p > 0.05). The plasmidome-focused metagenomics sequences (MiSeq platform (Illumina®)) revealed more than 100 ARG in the WWTP influent, which can potentially confer resistance to 14 pharmacological classes relevant in the human and veterinary clinical contexts, in which the qnr gene (resistance to fluoroquinolones) was the most prevalent. Only 7.8% of ARG were reduced after wastewater treatment, and the remaining 92.2% were associated with an increase in the prevalence of ARG linked to multidrug efflux pumps, substrate-specific for certain classes of antibiotics, or broad resistance to multiple medications. These data demonstrate that wastewater from poultry slaughterhouses plays a crucial role as an ARG reservoir and in the spread of AMR into the environment.202439395082
5352190.9998Microbiological characterization of aquatic microbiomes targeting taxonomical marker genes and antibiotic resistance genes of opportunistic bacteria. The dissemination of medically relevant antibiotic resistance genes (ARGs) (blaVIM-1, vanA, ampC, ermB, and mecA) and opportunistic bacteria (Enterococcus faecium/faecalis, Pseudomonas aeruginosa, Enterobacteriaceae, Staphylococcus aureus, and CNS) was determined in different anthropogenically influenced aquatic habitats in a selected region of Germany. Over a period of two years, four differently sized wastewater treatment plants (WWTPs) with and without clinical influence, three surface waters, four rain overflow basins, and three groundwater sites were analyzed by quantitative Polymerase Chain Reaction (qPCR). Results were calculated in cell equivalents per 100 ng of total DNA extracted from water samples and per 100 mL sample volume, which seems to underestimate the abundance of antibiotic resistance and opportunistic bacteria. High abundances of opportunistic bacteria and ARG were quantified in clinical wastewaters and influents of the adjacent WWTP. The removal capacities of WWTP were up to 99% for some, but not all investigated bacteria. The abundances of most ARG targets were found to be increased in the bacterial population after conventional wastewater treatment. As a consequence, downstream surface water and also some groundwater compartments displayed high abundances of all four ARGs. It became obvious that the dynamics of the ARG differed from the fate of the opportunistic bacteria. This underlines the necessity of an advanced microbial characterization of anthropogenically influenced environments.201525634736