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532000.8888Antimicrobial resistance genes in microbiota associated with sediments and water from the Akaki river in Ethiopia. The spread of antimicrobial-resistant pathogens is a global health concern. Most studies report high levels of antimicrobial resistance genes (ARGs) in the aquatic environment; however, levels associated with sediments are limited. This study aimed to investigate the distribution of ARGs in the sediments and water of the Akaki river in Addis Ababa, Ethiopia. The diversity and abundance of 84 ARGs and 116 clinically important bacteria were evaluated from the sediments and water collected from five sites in the Akaki river. Most of the ARGs were found in the city close to anthropogenic activities. Water samples collected in the middle catchment of the river contained 71-75% of targeted ARGs, with genes encoding aminoglycoside acetyltransferase (aac(6)-Ib-cr), aminoglycoside adenylyl transferase (aadA1), β-lactamase (bla(OXA-10))(,) quinolone resistance S (qnrS), macrolide efflux protein A (mefA), and tetracycline resistance (tetA), were detected at all sampling sites. Much fewer ARGs were detected in all sediments, and those near the hospitals had the highest diversity and level. Despite the lower levels and diversity, there were no unique ARGs detected in the sediments that were also not detected in the waters. A wide range of clinically relevant pathogens were also detected in the Akaki river. The findings suggest that the water phase, rather than the sediments in the Akaki river, is a potential conduit for the spread of ARGs and antibiotic-resistant bacteria.202235583762
775510.8886Anthropogenic impacts on sulfonamide residues and sulfonamide resistant bacteria and genes in Larut and Sangga Besar River, Perak. The environmental reservoirs of sulfonamide (SA) resistome are still poorly understood. We investigated the potential sources and reservoir of SA resistance (SR) in Larut River and Sangga Besar River by measuring the SA residues, sulfamethoxazole resistant (SMX(r)) in bacteria and their resistance genes (SRGs). The SA residues measured ranged from lower than quantification limits (LOQ) to 33.13 ng L(-1) with sulfadiazine (SDZ), sulfadimethoxine (SDM) and SMX as most detected. Hospital wastewater effluent was detected with the highest SA residues concentration followed by the slaughterhouse and zoo wastewater effluents. The wastewater effluents also harbored the highest abundance of SMX(r)-bacteria (10(7) CFU mL(-1)) and SRGs (10(-1)/16S copies mL(-1)). Pearson correlation showed only positive correlation between the PO(4) and SMX(r)-bacteria. In conclusion, wastewater effluents from the zoo, hospital and slaughterhouse could serve as important sources of SA residues that could lead to the consequent emergence of SMX(r)-bacteria and SRGs in the river.201931726563
348120.8878Antibiotics and Antibiotic Resistance Genes in Sediment of Honghu Lake and East Dongting Lake, China. Sediment is an ideal medium for the aggregation and dissemination of antibiotics and antibiotic resistance genes (ARGs). The levels of antibiotics and ARGs in Honghu Lake and East Dongting Lake of central China were investigated in this study. The concentrations of eight antibiotics (four sulfonamides and four tetracyclines) in Honghu Lake were in the range 90.00-437.43 μg kg(-1) (dry weight (dw)) with mean value of 278.21 μg kg(-1) dw, which was significantly higher than those in East Dongting Lake (60.02-321.04 μg kg(-1) dw, mean value of 195.70 μg kg(-1) dw). Among the tested three sulfonamide resistance genes (sul) and eight tetracycline resistance genes (tet), sul1, sul2, tetA, tetC, and tetM had 100 % detection frequency in sediment samples of East Dongting Lake, while only sul1, sul2, and tetC were observed in all samples of Honghu Lake. The relative abundance of sul2 was higher than that of sul1 at p < 0.05 level in both lakes. The relative abundance of tet genes in East Dongting Lake was in the following order: tetM > tetB > tetC > tetA. The relative abundance of sul1, sul2, and tetC in East Dongting Lake was significantly higher than those in Honghu Lake. The abundance of background bacteria may play an important role in the horizontal spread of sul2 and tetC genes in Honghu Lake and sul1 in East Dongting Lake, respectively. Redundancy analysis indicated that tetracyclines may play a more important role than sulfonamides in the abundance of sul1, sul2, and tetC gens in Honghu Lake and East Dongting Lake.201627418176
306330.8875Antibiotic resistance among coliform and fecal coliform bacteria isolated from the freshwater mussel Hydridella menziesii. Freshwater mussels (Hydridella menziesii) collected from Lakes Rotoroa, Rotoiti, and Brunner, South Island, New Zealand, contained coliform and fecal coliform bacteria. The majority of these bacteria were resistant to one or more antibiotics, but none transferred streptomycin, tetracycline, or kanamycin resistance to an antibiotic-susceptible strain of Escherichia coli K-12.1976779633
138340.8873Detection of Tetracycline Resistance Genes in European Hedgehogs (Erinaceus europaeus) and Crested Porcupines (Hystrix cristata). Relatively little is known regarding the role of wildlife in the development of antibiotic resistance. Our aim was to assess the presence of the tetracycline resistance genes, tet(A), tet(B), tet(C), tet(D), tet(E), tet(G), tet(K), tet(L), tet(M), tet(O), tet(P), tet(Q), tet(S), and tet(X), in tissue samples of 14 hedgehogs (Erinaceus europaeus) and 15 crested porcupines (Hystrix cristata) using PCR assays. One or more tet genes were found in all but three hedgehogs and one crested porcupine. Of the 14 tetracycline resistance genes investigated, 13 were found in at least one sample; tet(G) was not detected. We confirmed the potential role of wild animals as bioindicators, reservoirs, or vectors of antibiotic-resistant bacteria in the environment.202031526277
121450.8866Plasmid-mediated quinolone resistance genes in fecal bacteria from rooks commonly wintering throughout Europe. This study concerned the occurrence of fecal bacteria with plasmid-mediated quinolone resistance (PMQR) genes in rooks (Corvus frugilegus, medium-sized corvid birds) wintering in continental Europe during winter 2010/2011. Samples of fresh rook feces were taken by cotton swabs at nine roosting places in eight European countries. Samples were transported to one laboratory and placed in buffered peptone water (BPW). The samples from BPW were enriched and subcultivated onto MacConkey agar (MCA) supplemented with ciprofloxacin (0.06 mg/L) to isolate fluoroquinolone-resistant bacteria. DNA was isolated from smears of bacterial colonies growing on MCA and tested by PCR for PMQR genes aac(6')-Ib, qepA, qnrA, qnrB, qnrC, qnrD, qnrS, and oqxAB. All the PCR products were further analyzed by sequencing. Ciprofloxacin-resistant bacteria were isolated from 37% (392 positive/1,073 examined) of samples. Frequencies of samples with ciprofloxacin-resistant isolates ranged significantly from 3% to 92% in different countries. The qnrS1 gene was found in 154 samples and qnrS2 in 2 samples. The gene aac(6')-Ib-cr was found in 16 samples. Thirteen samples were positive for qnrB genes in variants qnrB6 (one sample), qnrB18 (one), qnrB19 (one), qnrB29 (one), and qnrB49 (new variant) (one). Both the qnrD and oqxAB genes were detected in six samples. The genes qnrA, qnrC, and qepA were not found. Wintering omnivorous rooks in Europe were commonly colonized by bacteria supposedly Enterobacteriaceae with PMQR genes. Rooks may disseminate these epidemiologically important bacteria over long distances and pose a risk for environmental contamination.201222731858
264560.8864High prevalence of a gene cluster conferring resistance to streptomycin, sulfonamide, and tetracycline in Escherichia coli isolated from indigenous wild birds. A total of 116 Escherichia coli isolates from cecal contents of 81 indigenous wild birds in Korea were tested for antimicrobial susceptibility. Seventy-one isolates from sparrows (Passer montanus) and one isolate from doves (Columba livia) were resistant to three antimicrobials, including streptomycin, sulfonamide, and tetracycline (SSuT). PCR and subsequent sequence analysis revealed the SSuT gene cluster region (approximately 13 kb) harboring genes encoding resistance to streptomycin (strA and strB), sulfonamide (sul2), and tetracycline (tetB, tetC, tetD, and tetR). In particular, tetracycline resistance genes were located on the transposon Tn10-like element. The SSuT element-harboring E. coli can be an important source of the transmission of antimicrobial resistance to other pathogenic bacteria. Therefore, strict sanitary measures in human and animal environments are necessary to prevent the spread of resistant bacteria through fecal residues of wild birds.202133487603
526270.8863High abundances of class 1 integrase and sulfonamide resistance genes, and characterisation of class 1 integron gene cassettes in four urban wetlands in Nigeria. There is little information about environmental contamination with antibiotic resistance genes (ARG) in Sub-Saharan Africa, home to about 1 billion people. In this study we measured the abundance of three genes (sul1, sul2, and intI1) used as indicators of environmental contamination with ARGs in the sediments of four urban wetlands in southwestern Nigeria by qPCR. In addition, we characterised the variable regions of class 1 integrons in sulfamethoxazole/trimethoprim (SMX/TRI)-resistant bacteria isolated from the wetlands by PCR and DNA sequencing. The indicator ARGs were present in all wetlands with mean absolute copy numbers/gram of sediment ranging between 4.7x106 and 1.2x108 for sul1, 1.1x107 and 1x108 for sul2, and 5.3x105 and 1.9x107 for intI1. The relative abundances (ARG/16S rRNA copy number) ranged from about 10-3 to 10-1. These levels of ARG contamination were similar to those previously reported for polluted environments in other parts of the world. The integrase genes intI1 and intI2 were detected in 72% and 11.4% SMX/TRI-resistant isolates, respectively. Five different cassette array types (dfrA7; aadA2; aadA1|dfrA1; acc(6')lb-cr|arr3|dfrA27; arr3|acc(6')lb-cr|dfrA27) were detected among 34 (59.6%) intI1-positive isolates. No gene cassettes were found in the nine intI2-positive isolates. These results show that African urban ecosystems impacted by anthropogenic activities are reservoirs of bacteria harbouring transferable ARG.201830496274
354380.8863Precipitation influences pathogenic bacteria and antibiotic resistance gene abundance in storm drain outfalls in coastal sub-tropical waters. Stormwater contamination can threaten the health of aquatic ecosystems and human exposed to runoff via nutrient and pathogen influxes. In this study, the concentrations of 11 bacterial pathogens and 47 antibiotic resistance genes (ARGs) were determined by using high-throughput microfluidic qPCR (MFQPCR) in several storm drain outfalls (SDOs) during dry and wet weather in Tampa Bay, Florida, USA. Data generated in this study were also compared with the levels of fecal indicator bacteria (FIB) and sewage-associated molecular markers (i.e., Bacteroides HF183 and crAssphage markers) in same SDOs collected in a recent study (Ahmed et al., 2018). Concentration of FIB, sewage-associated markers, bacterial pathogens and many ARGs in water samples were relatively high and SDOs may be potentially hotspots for microbial contamination in Tampa Bay. Mean concentrations of culturable E. coli and Enterococcus spp. were tenfold higher in wet compared to dry weather. The majority of microbiological contaminants followed this trend. E. coli eaeA, encoding the virulence factor intimin, was correlated with levels of 20 ARGs, and was more frequently detected in wet weather than dry weather samples. The bla(KPC) gene associated with carbapenem resistant Enterobacteriaceae and the beta-lactam resistant gene (bla(NPS)) were only detected in wet weather samples. Frequency of integron genes Intl2 and Intl3 detection increased by 42% in wet weather samples. Culturable E. coli and Enterococcus spp. significantly correlated with 19 of 47 (40%) ARG tested. Sewage-associated markers crAssphage and HF183 significantly correlated (p < 0.05) with the following ARGs: intl1, sul1, tet(M), ampC, mexB, and tet(W). The presence of sewage-associated marker genes along with ARGs associated with sewage suggested that aging sewage infrastructure contributed to contaminant loading in the Bay. Further research should focus on collecting spatial and temporal data on the microbiological contaminants especially viruses in SDOs.201829754026
526190.8861Prevalence of antibiotic resistance genes from effluent of coastal aquaculture, South Korea. The wide use of antibiotics in aquaculture for prophylactic and therapeutic purposes can potentially lead to the prevalence of antibiotic resistance genes (ARGs). This study reports for the first time the profile of ARGs from effluents of coastal aquaculture located in South Jeolla province and Jeju Island, South Korea. Using quantitative PCR (qPCR), twenty-two ARGs encoding tetracycline resistance (tetA, tetB, tetD, tetE, tetG, tetH, tetM, tetQ, tetX, tetZ, tetBP), sulfonamide resistance (sul1, sul2), quinolone resistance (qnrD, qnrS, aac(6')-Ib-cr), β-lactams resistance (bla(TEM), bla(CTX), bla(SHV)), macrolide resistance (ermC), florfenicol resistance (floR) and multidrug resistance (oqxA) and a class 1 integrons-integrase gene (intI1) were quantified. In addition, Illumina Miseq sequencing was applied to investigate microbial community differences across fish farm effluents. Results from qPCR showed that the total number of detected ARGs ranged from 4.24 × 10(-3) to 1.46 × 10(-2) copies/16S rRNA gene. Among them, tetB and tetD were predominant, accounting for 74.8%-98.0% of the total ARGs. Furthermore, intI1 gene showed positive correlation with tetB, tetD, tetE, tetH, tetX, tetZ tetQ and sul1. Microbial community analysis revealed potential host bacteria for ARGs and intI1. Two genera, Vibrio and Marinomonas belonging to Gammaproteobacteria, showed significant correlation with tetB and tetD, the most dominant ARGs in all samples. Also, operational taxonomic units (OTUs)-based network analysis revealed that ten OTUs, classified into the phyla Proteobacteria, Cyanobacteria/Chloroplast, Bacteroidetes, Verrucomicrobia and an unclassified phylum, were potential hosts of tetracycline resistance genes (i.e., tetA, tetG, tetH, tetM, tetQ and tetZ). Further systematic monitoring of ARGs is warranted for risk assessment and management of antibacterial resistance from fish farm effluents.201829031406
1382100.8856Surveillance of antimicrobial-resistant Escherichia coli in Sheltered dogs in the Kanto Region of Japan. There is a lack of an established antimicrobial resistance (AMR) surveillance system in animal welfare centers. Therefore, the AMR prevalence in shelter dogs is rarely known. Herein, we conducted a survey in animal shelters in Chiba and Kanagawa prefectures, in the Kanto Region, Japan, to ascertain the AMR status of Escherichia coli  (E. coli) prevalent in shelter dogs. E. coli was detected in the fecal samples of all 61 and 77 shelter dogs tested in Chiba and Kanagawa, respectively. The AMR was tested against 20 antibiotics. E. coli isolates derived from 16.4% and 26.0% of samples from Chiba and Kanagawa exhibited resistance to at least one antibiotic, respectively. E. coli in samples from Chiba and Kanagawa prefectures were commonly resistant to ampicillin, piperacillin, streptomycin, kanamycin, tetracycline, and nalidixic acid; that from the Kanagawa Prefecture to cefazolin, cefotaxime, aztreonam, ciprofloxacin, and levofloxacin and that from Chiba Prefecture to chloramphenicol and imipenem. Multidrug-resistant bacteria were detected in 18 dogs from both regions; β-lactamase genes (blaTEM, blaDHA-1, blaCTX-M-9 group CTX-M-14), quinolone-resistance protein genes (qnrB and qnrS), and mutations in quinolone-resistance-determining regions (gyrA and parC) were detected. These results could partially represent the AMR data in shelter dogs in the Kanto Region of Japan.202235031646
3498110.8854Comparative study on the bacterial diversity and antibiotic resistance genes of urban landscape waters replenished by reclaimed water and surface water in Xi'an, China. Pathogenic bacteria and antibiotic resistance genes (ARGs) in urban landscape waters may pose a potential threat to human health. However, the investigation of their occurrence in the urban landscape waters replenished by reclaimed water (RW) and surface water (SW) is still insufficient. The water samples collected from six urban landscape waters replenished by RW or SW were used to analyze bacterial diversity using high-throughput sequencing of 16S rRNA gene and to detect 18 ARGs and 2 integron-integrase genes by means of quantitative PCR array. Results indicated that Proteobacteria was the dominant phylum in all six urban landscape waters. The bacterial species richness was lower in urban landscape waters replenished by RW than that by SW. Sulfonamide resistance genes (sulI and sulIII) were the major ARGs in these urban landscape waters. No significant difference in the relative abundance of sulfonamide resistance genes, tetracycline resistance genes, and most of beta-lactam resistance genes was observed between RW-replenished and SW-replenished urban landscape waters. By contrast, the relative abundance of bla(ampC) gene and qnrA gene in RW-replenished urban landscape waters was significantly higher than that in SW-replenished urban landscape waters (p < 0.05), which suggested that use of RW may increase the amount of specific ARGs to urban landscape waters. Interestingly, among six urban landscape waters, RW-replenished urban landscape waters had a relatively rich variety of ARGs (12-15 of 18 ARGs) but a low relative abundance of ARGs (458.90-1944.67 copies/16S × 10(6)). The RW replenishment was found to have a certain impact on the bacterial diversity and prevalence of ARGs in urban landscape waters, which provide new insight into the effect of RW replenishment on urban landscape waters.202133786766
3482120.8854Metagenomic profiling of ARGs in airborne particulate matters during a severe smog event. Information is currently limited regarding the distribution of antibiotic resistance genes (ARGs) in smog and their correlations with airborne bacteria. This study characterized the diversity and abundance of ARGs in the particulate matters (PMs) of severe smog based on publicly available metagenomic data, and revealed the occurrence of 205 airborne ARG subtypes, including 31 dominant ones encoding resistance to 11 antibiotic types. Among the detectable ARGs, tetracycline, β-lactam and aminoglycoside resistance genes had the highest abundance, and smog and soil had similar composition characteristics of ARGs. During the smog event, the total abundance of airborne ARGs ranged from 4.90 to 38.07ppm in PM(2.5) samples, and from 7.61 to 38.49ppm in PM(10) samples, which were 1.6-7.7 times and 2.1-5.1 times of those in the non-smog day, respectively. The airborne ARGs showed complicated co-occurrence patterns, which were heavily influenced by the interaction of bacterial community, and physicochemical and meteorological factors. Lactobacillus and sulfonamide resistance gene sul1 were determined as keystones in the co-occurrence network of microbial taxa and airborne ARGs. The results may help to understand the distribution patterns of ARGs in smog for the potential health risk evaluation.201829751438
7096130.8853Sulfonamide and tetracycline resistance genes in total- and culturable-bacterial assemblages in South African aquatic environments. Antibiotic resistant bacteria are ubiquitous in the natural environment. The introduction of effluent derived antibiotic resistance genes (ARGs) into aquatic environments is of concern in the spreading of genetic risk. This study showed the prevalence of sulfonamide and tetracycline resistance genes, sul1, sul2, sul3, and tet(M), in the total bacterial assemblage and colony forming bacterial assemblage in river and estuarine water and sewage treatment plants (STP) in South Africa. There was no correlation between antibiotic concentrations and ARGs, suggesting the targeted ARGs are spread in a wide area without connection to selection pressure. Among sul genes, sul1 and sul2 were major genes in the total (over 10(-2) copies/16S) and colony forming bacteria assemblages (∼10(-1) copies/16S). In urban waters, the sul3 gene was mostly not detectable in total and culturable assemblages, suggesting sul3 is not abundant. tet(M) was found in natural assemblages with 10(-3) copies/16S level in STP, but was not detected in colony forming bacteria, suggesting the non-culturable (yet-to-be cultured) bacterial community in urban surface waters and STP effluent possess the tet(M) gene. Sulfamethoxazole (SMX) resistant (SMX(r)) and oxytetracycline (OTC) resistant (OTC(r)) bacterial communities in urban waters possessed not only sul1 and sul2 but also sul3 and tet(M) genes. These genes are widely distributed in SMX(r) and OTC(r) bacteria. In conclusion, urban river and estuarine water and STP effluent in the Durban area were highly contaminated with ARGs, and the yet-to-be cultured bacterial community may act as a non-visible ARG reservoir in certain situations.201526300864
7757140.8853Removal of antibiotics and antibiotic resistance genes from domestic sewage by constructed wetlands: Effect of flow configuration and plant species. This study aims to investigate the removal of antibiotics and antibiotic resistance genes (ARGs) in raw domestic wastewater by various mesocosm-scale constructed wetlands (CWs) with different flow configurations or plant species including the constructed wetland with or without plant. Six mesocosm-scale CWs with three flow types (surface flow, horizontal subsurface flow and vertical subsurface flow) and two plant species (Thaliadealbata Fraser and Iris tectorum Maxim) were set up in the outdoor. 8 antibiotics including erythromycin-H2O (ETM-H2O), monensin (MON), clarithromycin (CTM), leucomycin (LCM), sulfamethoxazole (SMX), trimethoprim (TMP), sulfamethazine (SMZ) and sulfapyridine (SPD) and 12 genes including three sulfonamide resistance genes (sul1, sul2 and sul3), four tetracycline resistance genes (tetG, tetM, tetO and tetX), two macrolide resistance genes (ermB and ermC), two chloramphenicol resistance genes (cmlA and floR) and 16S rRNA (bacteria) were determined in different matrices (water, particle, substrate and plant phases) from the mesocosm-scale systems. The aqueous removal efficiencies of total antibiotics ranged from 75.8 to 98.6%, while those of total ARGs varied between 63.9 and 84.0% by the mesocosm-scale CWs. The presence of plants was beneficial to the removal of pollutants, and the subsurface flow CWs had higher pollutant removal than the surface flow CWs, especially for antibiotics. According to the mass balance analysis, the masses of all detected antibiotics during the operation period were 247,000, 4920-10,600, 0.05-0.41 and 3500-60,000μg in influent, substrate, plant and effluent of the mesocosm-scale CWs. In the CWs, biodegradation, substrate adsorption and plant uptake all played certain roles in reducing the loadings of nutrients, antibiotics and ARGs, but biodegradation was the most important process in the removal of these pollutants.201627443461
3483150.8850Abundance and diversity of antibiotic resistance genes and bacterial communities in the western Pacific and Southern Oceans. This study investigated the abundance and diversity of antibiotic resistance genes (ARGs) and the composition of bacterial communities along a transect covering the western Pacific Ocean (36°N) to the Southern Ocean (74°S) using the Korean icebreaker R/V Araon (total cruise distance: 14,942 km). The relative abundances of ARGs and bacteria were assessed with quantitative PCR and next generation sequencing, respectively. The absolute abundance of ARGs was 3.0 × 10(6) ± 1.6 × 10(6) copies/mL in the western Pacific Ocean, with the highest value (7.8 × 10(6) copies/mL) recorded at a station in the Tasman Sea (37°S). The absolute abundance of ARGs in the Southern Ocean was 1.8-fold lower than that in the western Pacific Ocean, and slightly increased (0.7-fold) toward Terra Nova Bay in Antarctica, possibly resulting from natural terrestrial sources or human activity. β-Lactam and tetracycline resistance genes were dominant in all samples (88-99%), indicating that they are likely the key ARGs in the ocean. Correlation and network analysis showed that Bdellovibrionota, Bacteroidetes, Cyanobacteria, Margulisbacteria, and Proteobacteria were positively correlated with ARGs, suggesting that these bacteria are the most likely ARG carriers. This study highlights the latitudinal profile of ARG distribution in the open ocean system and provides insights that will help in monitoring emerging pollutants on a global scale.202235085628
7214160.8849Long-term application of fresh and composted manure increase tetracycline resistance in the arable soil of eastern China. The aim of this study was to compare the occurrence, abundance, and diversity of tetracycline resistance genes (tet) in agricultural soils after 6 years' application of fresh or composted swine manure. Soil samples were collected from fresh or composted manure-treated farmland at three depths (0-5 cm, 5-10 cm, and 10-20 cm). Nine classes of tet genes [tetW, tetB(P), tetO, tetS, tetC, tetG, tetZ, tetL, and tetX] were detected; tetG, tetZ, tetL, and tetB(P) were predominant in the manure-treated soil. The abundances of tetB(P), tetW, tetC, and tetO were reduced, while tetG and tetL were increased by fertilizing with composted versus fresh manure; thus, the total abundance of tet genes was not significantly reduced by compost manuring. tetG was the most abundant gene in manure-treated soil; the predominant tetG genotypes shared high homology with pathogenic bacteria. The tetG isolates were more diverse in soils treated with fresh versus composted manure, although the residual tet genes in composted manure remain a pollutant and produce a different influence on the tet gene resistome in field soil.201525460961
3542170.8849Fecal indicators, pathogens, antibiotic resistance genes, and ecotoxicity in Galveston Bay after Hurricane Harvey. Unprecedented rainfall after Hurricane Harvey caused a catastrophic flood in the southern coast of Texas, and flushed significant floodwater and sediments into Galveston Bay, the largest estuary along the Texas Gulf Coast. This study investigated the immediate and long-term (6 months post-Harvey) fecal indicators, pathogenic bacteria, antibiotic resistance genes (ARGs), and ecotoxicity in the Galveston Bay. Dramatic decrease of salinity profile to zero, increased levels of fecal indicator bacteria and pathogenic bacteria, and detection of various ARGs were observed in the water and sediment samples collected 2 weeks post-Harvey. High levels of Bla(TEM) and cytotoxicity measured by yeast bioluminescent assay (BLYR) were also observed especially near the river mouths. While Vibrio spp. was dominant in water, much higher abundance of fecal indicator bacteria and pathogen were detected in the sediments. A decreasing trend of Bla(TEM) and cytotoxicity was observed in March 2018 samples, suggesting the Bay has returned to its pre-hurricane conditions 6 months post-Harvey. Interestingly, the abundance of fecal indicator bacteria and pathogens were shifted dramatically according to high-streamflow and low-streamflow seasons in the Bay. The data are useful to construct the model of risk assessment in coastal estuaries system and predict the effects of extreme flooding events in the future.202133445049
7211180.8848Contribution of Manure-Spreading Operations to Bioaerosols and Antibiotic Resistance Genes' Emission. Manure spreading from farm animals can release antibiotic-resistant bacteria (ARB) carrying antimicrobial resistance genes (ARGs) into the air, posing a potential threat to human and animal health due to the intensive use of antibiotics in the livestock industry. This study analyzed the effect of different manure types and spreading methods on airborne bacterial emissions and antibiotic resistance genes in a controlled setting. Cow, poultry manure, and pig slurry were spread in a confined environment using two types of spreaders (splash plate and dribble bar), and the resulting emissions were collected before, during, and after spreading using high-volume air samplers coupled to a particle counter. Total bacteria, fecal indicators, and a total of 38 different subtypes of ARGs were further quantified by qPCR. Spreading poultry manure resulted in the highest emission rates of total bacteria (10(11) 16S gene copies/kg manure spread), Archaea (10(6) 16S gene copies/kg manure), Enterococcus (10(5) 16S gene copies/kg manure), and E. coli (10(4) 16S gene copies/kg manure), followed by cow manure and pig slurry with splash plates and the dribble bar. Manure spreading was associated with the highest rates of airborne aminoglycoside genes for cow and poultry (10(6) gene copies/kg manure), followed by pig slurry (10(4) gene copies/kg manure). This study shows that the type of manure and spreading equipment can affect the emission rates of airborne bacteria, and ARGs.202337512969
7213190.8848Distribution characteristics of antibiotic resistant bacteria and genes in fresh and composted manures of livestock farms. Livestock manure is a major reservoir of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). This study investigated the distribution characteristics of ARB, ARGs in fresh and composted manures of traditional breading industry in rural areas in China. Samples collected were naturally piled without professional composting, and will be applied to farmland. The real-time quantitative polymerase chain reaction (qPCR) results showed the presence of ten target ARGs and two mobile genetic elements (MGEs) in the tested manure samples. The relative abundance of tetracycline and sulfonamide resistance genes (TRGs and SRGs) was generally higher than that of macrolide resistance genes (MRGs), followed by quinolone resistance genes (QRGs). There were significant positive correlations between the abundance of sul1, sul2, tetW and MGEs (intl1, intl2). In addition, the distribution of target ARGs was associated with the residual concentrations of doxycycline (DOX), sulfamethazine (SM2), enrofloxacin (ENR) and tylosin (TYL). Overall, a total of 24 bacterial genera were identified. The resistance rates of ARB were 17.79%-83.70% for SM2, followed 0.40%-63.77% for TYL, 0.36%-43.90% for DOX and 0.00%-13.36% for ENR, which showed a significant dose-effect. This study also demonstrated that the abundance of clinically relevant ARB and ARGs in chicken, swine and cow fresh manures significantly greater than that in composted manures, and chicken and swine manures had higher proportion of ARB and higher abundance of ARGs than that in cow manures.201931756854