# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 1214 | 0 | 0.9860 | Plasmid-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. | 2012 | 22731858 |
| 5262 | 1 | 0.9848 | High 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. | 2018 | 30496274 |
| 5245 | 2 | 0.9844 | Antimicrobial Resistance in U.S. Retail Ground Beef with and without Label Claims Regarding Antibiotic Use. ABSTRACT: Antibiotics used during food animal production account for approximately 77% of U.S. antimicrobial consumption by mass. Ground beef products labeled as raised without antibiotics (RWA) are perceived to harbor lower levels of antimicrobial-resistant bacteria than conventional (CONV) products with no label claims regarding antimicrobial use. Retail ground beef samples were obtained from six U.S. cities. Samples with an RWA or U.S. Department of Agriculture Organic claim (n = 299) were assigned to the RWA production system. Samples lacking these claims (n = 300) were assigned to the CONV production system. Each sample was cultured for the detection of five antimicrobial-resistant bacteria. Genomic DNA was isolated from each sample, and a quantitative PCR assay was used to determine the abundance of 10 antimicrobial resistance (AMR) genes. Prevalence of tetracycline-resistant Escherichia coli (CONV, 46.3%; RWA, 34.4%; P < 0.01) and erythromycin-resistant Enterococcus (CONV, 48.0%; RWA, 37.5%; P = 0.01) was higher in CONV ground beef. Salmonella was detected in 1.2% of samples. The AMR gene blaCTX-M (CONV, 4.1 log-normalized abundance; RWA, 3.8 log-normalized abundance; P < 0.01) was more abundant in CONV ground beef. The AMR genes mecA (CONV, 4.4 log-normalized abundance; RWA, 4.9 log-normalized abundance; P = 0.05), tet(A) (CONV, 3.9 log-normalized abundance; RWA, 4.5 log-normalized abundance; P < 0.01), tet(B) (CONV, 3.9 log-normalized abundance; RWA, 4.5 log-normalized abundance; P < 0.01), and tet(M) (CONV, 5.4 log-normalized abundance; RWA, 5.8 log-normalized abundance; P < 0.01) were more abundant in RWA ground beef. Although these results suggest that antimicrobial use during U.S. cattle production does not increase human exposure to antimicrobial-resistant bacteria via ground beef, quantitative microbiological risk assessments are required for authoritative determination of the human health impacts of the use of antimicrobial agents during beef production. | 2021 | 33302298 |
| 3550 | 3 | 0.9841 | Conjugative transmission of antibiotic-resistance from stream water Escherichia coli as related to number of sulfamethoxazole but not class 1 and 2 integrase genes. A conjugation assay was used to determine the effects of phenotypic resistance to one to up to 5 antibiotics, sampling site of origin, presence or absence of class 1 and/or class 2 integrase (intI) genes (intI1 and intI2), and the number of sulfamethoxazole resistance (sul) and trimethoprim resistance (dfr) genes on the transfer frequencies of plasmids from environmental, antibiotic-resistant Escherichia coli. Of 51 sulfamethoxazole and trimethoprim-resistant E. coli isolates conferring at least one mob gene (mob(P51), mob(F11), mob(F12), mob(Q11), mob(Q12) , or mob(Qu) ), 38 produced transconjugants with an overall mean frequency of 1.60 × 10(-3) transconjugants/ donors (T/D) or 5.89 × 10(-3) transconjugants/recipients (T/R). The presence or absence of intI1 and intI2 and the presence or absence of different targeted dfr genes (dfrA1, dfrA8, dfrA12, dfrA14, dfrA17, and/or dfrB3) were not statistically related to plasmid transfer frequencies as determined by ANOVA (P ≥ 0.05). However, E. coli isolates recovered 2 km downstream of wastewater treatment plant effluent input, and those possessing resistance to 3 antibiotics had significantly greater plasmid transfer frequency than their counterparts when calculated as T/D (ANOVA followed by Fisher's least significant difference means comparison, P < 0.05). Greater plasmid transfer frequency calculated as T/D was also measured for E. coli possessing 3 compared to a single sul gene. The in-vitro frequency suggests that horizontal gene transfer of conjugative mediated-antibiotic (sul) resistance genes may be significant among resistant, stream bacteria. | 2016 | 28090382 |
| 834 | 4 | 0.9841 | Molecular diversity of class 2 integrons in antibiotic-resistant gram-negative bacteria found in wastewater environments in China. The molecular architecture of class 2 integrons among gram-negative bacteria from wastewater environments was investigated in Jinan, China. Out of the 391 antibiotic-resistant bacteria found, 38 isolates harboring class 2 integrons encoding potentially transferrable genes that could confer antibiotic resistance were found. These isolates were classified into 19 REP-PCR types. These strains were identified using 16S rRNA gene sequencing and found to be as follows: Proteus mirabilis (16), Escherichia coli (7), Providencia spp. (7), Proteus spp. (2), P. vulgaris (3), Shigella sp. (1), Citrobacter freundii (1), and Acinetobacter sp. (1). Their class 2 integron cassette arrays were amplified and then either analyzed using PCR-RFLP or sequenced. The typical array dfrA1-sat2-aadA1 was detected in 27 isolates. Six atypical arrays were observed, including three kinds of novel arrangements (linF2(∆attC1)-dfrA1(∆attC2)-aadA1-orf441 or linF2(∆attC1)-dfrA1(∆attC2)-aadA1, dfrA1-catB2-sat2-aadA1, and estX(Vr)-sat2-aadA1) and a hybrid with the 3'CS of class 1 integrons (dfrA1-sat2-aadA1-qacH), and dfrA1-sat1. Twenty-four isolates were also found to carry class 1 integrons with 10 types of gene cassette arrays. Several non-integron-associated antibiotic resistance genes were found, and their transferability was investigated. Results showed that water sources in the Jinan region harbored a diverse community of both typical and atypical class 2 integrons, raising concerns about the overuse of antibiotics and their careless disposal into the environment. | 2013 | 23264021 |
| 5257 | 5 | 0.9839 | Removal of fecal indicator bacteria and antibiotic resistant genes in constructed wetlands. Wastewater discharge evidently increased bacterial diversity in the receiving waterbodies. The objective of this study was to evaluate the effectiveness of a constructed wetland in reducing fecal indicator bacteria (FIB) and antibiotic resistant genes (ARGs). We determined the prevalence and attenuation of fecal indicator bacteria including Escherichia coli and enterococci, along with ARGs, and human-associated Bacteroidales (HF183) markers by quantitative polymerase chain reaction (qPCR) method. Three types of water samples (inlet, intermediate, and outlet) from a constructed wetland were collected once a month from May to December in 2013. The overall reduction of E. coli was 50.0% based on culture method. According to the qPCR result, the overall removal rate of E. coli was only 6.7%. Enterococci were found in 62.5% of the wetland samples. HF183 genetic marker was detected in all final effluent samples with concentration ranging from 1.8 to 4.22 log(10) gene copies (GC)/100 ml. Of the ARGs tested, erythromycin resistance genes (ermF) were detected in 79.2% of the wetland samples. The class 1 integrase (intI1) was detected in all water samples with concentration ranging from 0.83 to 5.54 log(10) GC/100 ml. The overall removal rates of enterococci, HF183, intI1, and ermF were 84.0%, 66.6%, 67.2%, and 13.1%, respectively. | 2019 | 30758793 |
| 7214 | 6 | 0.9838 | Long-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. | 2015 | 25460961 |
| 5281 | 7 | 0.9837 | Bacteria populating freshly appeared supraglacial lake possess metals and antibiotic-resistant genes. Antibiotic resistance (AR) has been extensively studied in natural habitats and clinical applications. AR is mainly reported with the use and misuse of antibiotics; however, little is known about its presence in antibiotic-free remote supraglacial lake environments. This study evaluated bacterial strains isolated from supraglacial lake debris and meltwater in Dook Pal Glacier, northern Pakistan, for antibiotic-resistant genes (ARGs) and metal-tolerant genes (MTGs) using conventional PCR. Several distinct ARGs were reported in the bacterial strains isolated from lake debris (92.5%) and meltwater (100%). In lake debris, 57.5% of isolates harbored the bla(TEM) gene, whereas 58.3% of isolates in meltwater possessed bla(TEM) and qnrA each. Among the ARGs, qnrA was dominant in debris isolates (19%), whereas in meltwater isolates, qnrA (15.2%) and bla(TEM) (15.2%) were dominant. ARGs were widely distributed among the bacterial isolates and different bacteria shared similar types of ARGs. Relatively greater number of ARGs were reported in Gram-negative bacterial strains. In addition, 92.5% of bacterial isolates from lake debris and 83.3% of isolates from meltwater harbored MTGs. Gene copA was dominant in meltwater isolates (50%), whereas czcA was greater in debris bacterial isolates (45%). Among the MTGs, czcA (18.75%) was dominant in debris strains, whereas copA (26.0%) was greater in meltwater isolates. This presents the co-occurrence and co-selection of MTGs and ARGs in a freshly appeared supraglacial lake. The same ARGs and MTGs were present in different bacteria, exhibiting horizontal gene transfer (HGT). Both positive and negative correlations were determined between ARGs and MTGs. The research provides insights into the existence of MTGs and ARGs in bacterial strains isolated from remote supraglacial lake environments, signifying the need for a more detailed study of bacteria harboring ARGs and MTGs in supraglacial lakes. | 2024 | 38262510 |
| 5260 | 8 | 0.9837 | Occurrence and Abundance of Antibiotic Resistance Genes in Chinese Traditional Pickles. With the widespread application and even misuse of antibiotics, antibiotic resistance genes (ARGs) are extensively present in various environments, from natural environment to fermented foods, posing emerging threat to public and environmental health. The real-time fluorescence quantitative PCR (qPCR) technique is commonly used to detect ARGs of environmental samples such as soil or water. In this study, eight types of pickles were collected from four regions of China and the existence of 13 resistance genes was assessed by qPCR. The results showed that a total of 11 resistance genes were detected in pickles, the blaTEM gene was detected in all samples, and the neo and cat genes were absent. The abundance of resistance genes varied, aada1 (1.09 × 10(5) to 5.94 × 10(6) copies/g), blaTEM (1.48 × 10(5) to 2.2 × 10(6) copies/g), ermc (1.01 × 10(5) to 5.35 × 10(5) copies/g), hyg (1.35 × 10(5) to 1.93 × 10(6) copies/g), aadd (4.46 × 10(5) to 1.60 × 10(6) copies/g), nat1 (1.04 × 10(5) to 5.04 × 10(5) copies/g), nptII (2.17 × 10(4) to 1.69 × 10(5) copies/g), sul1 (2.01 × 10(5) to 4.60 × 10(5) copies/g), tetl (1.23 × 10(5) to 6.18 × 10(5) copies/g), shble (1.68 × 10(4) copies/g), and stra (4.8 × 10(4) to 1.9 × 10(5)copies/g). We also discussed the specificity and sensitivity assessment of qPCR applied to ARGs analysis in pickles, verifying the feasibility and validity of the method. Bacteria were isolated and purified from pickles as well and their antimicrobial resistance was studied. This study is of great significance for the risk assessment of resistance genes in pickles. Effective and preventive solutions were proposed to reduce the spread of resistance genes and protect public dietary health. | 2025 | 40230011 |
| 7210 | 9 | 0.9837 | Managing Beef Backgrounding Residual Soil Contaminants by Alum and Biochar Amendments. Heavy manure-derived contamination of soils can make animal congregating areas nonpoint sources for environmental pollution. In situ soil stabilization is a cost-effective management strategy with a focus on lowering contaminant availability and limiting release to the environment. Soil stabilizing amendments can help mitigate the negative environmental impacts of contaminated soils. In this 2-yr study, we examined the effects of adding no amendment (control) or treating with alum [Al (SO)⋅18HO] or biochar as soil amendments on Mehlich-3 extractable soil P, Cu, and Zn contents, antimicrobial monensin concentrations, total bacteria (16S ribosomal RNA [rRNA] gene), antibiotic resistance genes (1 and B), and Class 1 integrons (1) in an abandoned beef backgrounding setting. The alum reduced soil P (1374 to 1060 mg kg), Cu (7.7 to 3.2 mg kg), and Zn (52.4 to 19.6 mg kg) contents. Both alum and biochar reduced monesin concentrations (1.8 to 0.7 and 2.1 to 1.1 ng g, respectively). All the treatments harbored consistent 16 rRNA concentrations (10 copies g) throughout. The B gene concentration (10 copies g) was lower than either the 1 or the 1 genes (10 copies g), regardless of treatments. However, concentrations of all genes in the soils of animal congregation areas were higher than those in background soils with the least animal impact. In contrast with the effect on other contaminants, the effect of soil amendments on bacteria with antibiotic resistance genes was not biologically significant. Future research should be directed toward evaluating effective alternative methods to mitigate these bacterial populations. | 2018 | 30272780 |
| 1138 | 10 | 0.9837 | Occurrence of plasmid mediated fluoroquinolone resistance genes amongst enteric bacteria isolated from human and animal sources in Delta State, Nigeria. Plasmid mediated quinolone resistance (PMQR) is a public health challenge arising among other things, from indiscriminate use of the floroquinolones (FQr) prophylactically in animal husbandry. This study examines the occurrence of PMQR genes amongst enteric bacteria isolated from human and animal sources. A total of 720 (360 stool and 360 fish pond water/poultry litter) samples were examined for fluoroquinolone resistant (FQr) bacteria. Percentage FQr was generally higher among human isolates than isolates from animals. Proportion of PMQR amongst FQr isolates were (1.05 and 4.32) % for E. coli from human and animal sources. For Salmonella spp., Shigella spp., Klebsiella spp. and Aeromonas spp., percentages PMQR were 0.00 & 6.93, 0.00 & 6.38, 4.26 & 5.26 and 0.00 &3.03 for human and animal sources respectively, for the isolates. The PMQR genes: qnrA, qnr B, qnr S and qep A were 11, 15, 7 and 1 amongst a total of 1018 FQr and 29 PMQR isolates respectively. The aac (6')-Ib-cr gene was not detected in this study. Approximate Plasmid bands of PCR amplicon for qnr A, qnr B, qnr S and qep A respectively were established. The proportion of PMQR genes especially among isolates from animal sources is of public health concern due to the higher possibility of a horizontal FQ resistance transfer to humans. | 2021 | 33659770 |
| 5261 | 11 | 0.9837 | Prevalence 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. | 2018 | 29031406 |
| 7212 | 12 | 0.9837 | Simulated Winter Incubation of Soil With Swine Manure Differentially Affects Multiple Antimicrobial Resistance Elements. Gastrointestinal bacteria that harbor antibiotic resistance genes (ARG) become enriched with antibiotic use. Livestock manure application to cropland for soil fertility presents a concern that ARG and bacteria may proliferate and be transported in the environment. In the United States, manure applications typically occur during autumn with slow mineralization until spring planting season. A laboratory soil incubation study was conducted mimicking autumn swine manure application to soils with concentrations of selected ARG monitored during simulated 120-day winter incubation with multiple freeze-thaw events. Additionally, the effects of two soil moistures [10 and 30% water holding capacity (WHC)] and two manure treatments [raw versus hydrated lime alkaline stabilization (HLAS)] were assessed. Fourteen tetracycline resistance genes were evaluated; tet(D), tet(G), and tet(L) were detected in background soil while swine manure contained tet(A), tet(B), tet(C), tet(G), tet(M), tet(O), tet(Q), and tet(X). By day 120, the manure-borne tet(M) and tet(O) were still detected while tet(C), tet(D), tet(L), and tet(X) genes were detected less frequently. Other tet resistance genes were detected rarely, if at all. The sum of unique tet resistance genes among all treatments decreased during the incubation from an average of 8.9 to 3.8 unique tet resistance genes. Four resistance elements, intI1, bla (ctx-m-32), sul(I), erm(B), and 16s rRNA genes were measured using quantitative PCR. ARG abundances relative to 16S abundance were initially greater in the raw manure compared to background soil (-1.53 to -3.92 log abundance in manure; -4.02 to <-6.7 log abundance in soil). In the mixed manure/soil, relative abundance of the four resistance elements decreased (0.87 to 1.94 log abundance) during the incubation largely because 16S rRNA genes increased by 1.21 log abundance. Throughout the incubation, the abundance of intI1, bla (ctx-m-32), sul(I), and erm(B) per gram in soil amended with HLAS-treated manure was lower than in soil amended with raw manure. Under low initial soil moisture conditions, HLAS treatment reduced the abundance of intI1 and resulted in loss of bla (ctx-m-32), sul(I), and erm(B)] compared to other treatment-moisture combinations. Although one might expect antibiotic resistance to be relatively unchanged after simulated winter manure application to soil, a variety of changes in diversity and relative abundance can be expected. | 2020 | 33391241 |
| 7773 | 13 | 0.9835 | Correlation of tetracycline and sulfonamide antibiotics with corresponding resistance genes and resistant bacteria in a conventional municipal wastewater treatment plant. Antibiotics and corresponding resistance genes and resistant bacteria have been considered as emerging pollutants worldwide. Wastewater treatment plants (WWTPs) are potential reservoirs contributing to the evolution and spread of antibiotic resistance. In this study, total concentrations of tetracycline and sulfonamide antibiotics in final effluent were detected at 652.6 and 261.1ng/L, respectively, and in treated sludge, concentrations were at 1150.0 and 76.0μg/kg dry weight (dw), respectively. The quantities of antibiotic resistance genes and antibiotic resistant bacteria in final effluent were quantified in the range of 9.12×10(5)-1.05×10(6) gene abundances /100mL (genomic copies/100mL) and 1.05×10(1)-3.09×10(3)CFU/mL, respectively. In treated sludge, they were quantified at concentrations of 1.00×10(8)-1.78×10(9) gene abandances/100mL and 7.08×10(6)-1.91×10(8)CFU/100mL, respectively. Significant reductions (2-3 logs, p<0.05) of antibiotic resistance genes and antibiotic resistant bacteria were observed between raw influent and final effluent. The gene abundances of tetO and tetW normalized to that of 16S rRNA genes indicated an apparent decrease as compared to sulI genes, which remained stable along each treatment stage. Significant correlations (R(2)=0.75-0.83, p<0.05) between numbers of resistant bacteria and antibiotic concentrations were observed in raw influent and final effluent. No significance (R(2)=0.15, p>0.05) was found between tet genes (tetO and tetW) with concentration of tetracyclines identified in wastewater, while a significant correlation (R(2)=0.97, p<0.05) was observed for sulI gene and total concentration of sulfonamides. Correlations of the quantities of antibiotic resistance genes and antibiotic resistant bacteria with corresponding concentrations of antibiotics in sludge samples were found to be considerably weak (R(2)=0.003-0.07). | 2012 | 22369865 |
| 7786 | 14 | 0.9835 | Effect of solar photo-Fenton process in raceway pond reactors at neutral pH on antibiotic resistance determinants in secondary treated urban wastewater. Solar photo-Fenton process in raceway pond reactors was investigated at neutral pH as a sustainable tertiary treatment of real urban wastewater. In particular, the effect on antibiotic resistance determinants was evaluated. An effective inactivation of different wild bacterial populations was achieved considering total and cefotaxime resistant bacteria. The detection limit (1 CFU mL(-1)) was achieved in the range 80-100 min (5.4-6.7 kJ L(-1) of cumulative solar energy required) for Total Coliforms (TC) (40-60 min for resistant TC, 4.3-5.2 kJ L(-1)), 60-80 min (4.5-5.4 kJ L(-1)) for Escherichia coli (E. coli) (40 min for resistant E. coli, 4.1-4.7 kJ L(-1)) and 40-60 min (3.9-4.5 kJ L(-1)) for Enterococcus sp. (Entero) (30-40 min for resistant Entero, 3.2-3.8 kJ L(-1)) with 20 mg L(-1) Fe(2+) and 50 mg L(-1) H(2)O(2). Under these mild oxidation conditions, 7 out of the 10 detected antibiotics were effectively removed (60-100%). As the removal of antibiotic resistance genes (ARGs) is of concern, no conclusive results were obtained, as sulfonamide resistance gene was reduced to some extent (relative abundance <1), meanwhile class 1 integron intI1 and ß-lactam resistance genes were not affected. Accordingly, more research and likely more intensive oxidative conditions are needed for an efficient ARGs removal. | 2019 | 31202058 |
| 1380 | 15 | 0.9835 | Distribution of tetracycline and streptomycin resistance genes and class 1 integrons in Enterobacteriaceae isolated from dairy and nondairy farm soils. The prevalence of selected tetracycline and streptomycin resistance genes and class 1 integrons in Enterobacteriaceae (n = 80) isolated from dairy farm soil and nondairy soils was evaluated. Among 56 bacteria isolated from dairy farm soils, 36 (64.3%) were resistant to tetracycline, and 17 (30.4%) were resistant to streptomycin. Lower frequencies of tetracycline (9 of 24 or 37.5%) and streptomycin (1 of 24 or 4.2%) resistance were observed in bacteria isolated from nondairy soils. Bacteria (n = 56) isolated from dairy farm soil had a higher frequency of tetracycline resistance genes including tetM (28.6%), tetA (21.4%), tetW (8.9%), tetB (5.4%), tetS (5.4%), tetG (3.6%), and tetO (1.8%). Among 24 bacteria isolated from nondairy soils, four isolates carried tetM, tetO, tetS, and tetW in different combinations; whereas tetA, tetB, and tetG were not detected. Similarly, a higher prevalence of streptomycin resistance genes including strA (12.5%), strB (12.5%), ant(3'') (12.5), aph(6)-1c (12.5%), aph(3'') (10.8%), and addA (5.4%) was detected in bacteria isolated from dairy farm soils than in nondairy soils. None of the nondairy soil isolates carried aadA gene. Other tetracycline (tetC, tetD, tetE, tetK, tetL, tetQ, and tetT) and streptomycin (aph(6)-1c and ant(6)) resistance genes were not detected in both dairy and nondairy soil isolates. A higher distribution of multiple resistance genes was observed in bacteria isolated from dairy farm soil than in nondairy soil. Among 36 tetracycline- and 17 streptomycin-resistant isolates from dairy farm soils, 11 (30.6%) and 9 (52.9%) isolates carried multiple resistance genes encoding resistance to tetracycline and streptomycin, respectively, which was higher than in bacteria isolated from nondairy soils. One strain each of Citrobacter freundii and C. youngae isolated from dairy farm soils carried class 1 integrons with different inserted gene cassettes. Results of this small study suggest that the presence of multiple resistance genes and class 1 integrons in Enterobacteriaceae in dairy farm soil may act as a reservoir of antimicrobial resistance genes and could play a role in the dissemination of these antimicrobial resistance genes to other commensal and indigenous microbial communities in soil. However, additional longer-term studies conducted in more locations are needed to validate this hypothesis. | 2008 | 17701242 |
| 8033 | 16 | 0.9835 | Fate of pirlimycin and antibiotic resistance genes in dairy manure slurries in response to temperature and pH adjustment. Quantifying the fate of antibiotics and antibiotic resistance genes (ARGs) in response to physicochemical factors during storage of manure slurries will aid in efforts to reduce the spread of resistance when manure is land-applied. The objectives of this study were to determine the effects of temperature (10, 35, and 55 °C) and initial pH (5, 7, 9, and 12) on the removal of pirlimycin and prevalence of ARGs during storage of dairy manure slurries. We collected and homogenized feces and urine from five lactating dairy cows treated with pirlimycin and prepared slurries by mixing manure and sterile water. Aliquots (200 mL) of slurry were transferred and incubated in 400 mL glass beakers under different temperatures (10, 35, and 55 °C) or initial pH (5, 7, 9, and 12). Pirlimycin concentration and abundances of 16S rRNA, mefA, tet(W), and cfxA as indicators of total bacteria and ARGs corresponding to macrolide, tetracycline, and β-lactam resistance, respectively, were analyzed during manure incubation. The thermophilic environment (55 °C) increased the deconjugation and removal of pirlimycin, while the acidic shock at pH 5 increased deconjugation but inhibited removal of pirlimycin, suggesting that the chemical stability of pirlimycin could be affected by temperature and pH. The thermophilic environment decreased mefA relative abundance on day 7 and 28 (P = 0.02 and 0.04), which indicates that the bacteria that encoded mefA gene were not thermotolerant. Although mefA relative abundance was greater at the pH 9 shock than the rest of pH treatments on day 7 (P = 0.04), no significant pH effect was observed on day 28. The tet(W) abundance under initial pH 12 shock was less than other pH shocks on day 28 (P = 0.01), while no temperature effect was observed on day 28. There was no significant temperature and initial pH effect on cfxA abundance at any time point during incubation, implying that the bacteria that carrying cfxA gene are relatively insensitive to these environmental factors. Overall, directly raising temperature and pH can facilitate pirlimycin removal and decrease mefA and tet(W) relative abundances during storage of manure slurries. | 2020 | 32050366 |
| 1369 | 17 | 0.9835 | Antimicrobial resistance genes in Escherichia coli isolates recovered from a commercial beef processing plantt. The goal of this study was to assess the distribution of antimicrobial resistance (AMR) genes in Escherichia coli isolates recovered from a commercial beef processing plant. A total of 123 antimicrobial-resistant E. coli isolates were used: 34 from animal hides, 10 from washed carcasses, 27 from conveyers for moving carcasses and meat, 26 from beef trimmings, and 26 from ground meat. The AMR genes for beta-lactamase (bla(CMY), bla(SHV), and bla(TEM), tetracycline (tet(A), tet(B), and tet(C)), sulfonamides (sul1, sul2, and sul3), and aminoglycoside (strA and strB) were detected by PCR assay. The distribution of tet(B), tet(C), sul1, bla(TEM), strA, and strB genes was significantly different among sample sources. E. coli isolates positive for the tet(B) gene and for both strA and strB genes together were significantly associated with hide, washed carcass, and ground meat samples, whereas sull gene was associated with washed carcass and beef trimming samples. The bla(TEM) gene was significantly associated with ground meat samples. About 50% of tetracycline-resistant E. coli isolates were positive for tet(A) (14%), tet(B) (15%), or tet(C) (21%) genes or both tet(B) and tet(C) genes together (3%). The sul2 gene or both sul1 and sul2 genes were found in 23% of sulfisoxazole-resistant E. coli isolates, whereas the sul3 gene was not found in any of the E. coli isolates tested. The majority of streptomycin-resistant E. coli isolates (76%) were positive for the strA and strB genes together. The bla(CMY), bla(TEM), and bla(SHV) genes were found in 12, 56, and 4%, respectively, of ampicillin-resistant E. coli isolates. These data suggest that E. coli isolates harboring AMR genes are widely distributed in meat processing environments and can create a pool of transferable resistance genes for pathogens. The results of this study underscore the need for effective hygienic and sanitation procedures in meat plants to reduce the risks of contamination with antimicrobial-resistant bacteria. | 2009 | 19517739 |
| 5247 | 18 | 0.9835 | Similar Levels of Antimicrobial Resistance in U.S. Food Service Ground Beef Products with and without a "Raised without Antibiotics" Claim. U.S. ground beef with "raised without antibiotics" (RWA) label claims are perceived as harboring fewer bacteria with antimicrobial resistance (AMR) than are found in conventional (CONV) ground beef with no such label claim. A total of 370 ground beef samples from CONV ( n = 191) and RWA ( n = 179) production systems were collected over 13 months from three food service suppliers. The following bacteria were cultured: Escherichia coli, tetracycline-resistant (TET(r)) E. coli, third-generation cephalosporin-resistant (3GC(r)) E. coli, Salmonella enterica, TET(r) S. enterica, 3GC(r) S. enterica, nalidixic acid-resistant S. enterica, Enterococcus spp., erythromycin-resistant Enterococcus spp., TET(r) Enterococcus spp., Staphylococcus aureus, and methicillin-resistant S. aureus. TET(r) E. coli was more frequently detected in CONV ground beef (CONV, 54.2%; RWA, 35.2%; P < 0.01), but supplier ( P < 0.01) and production system × suppler interaction ( P < 0.01) effects were also significant. Metagenomic DNA was isolated from each sample, and equal amounts of metagenomic DNA were pooled by supplier, month, and production system for 75 pooled samples (38 CONV, 37 RWA). The abundance of aac(6')-Ie-aph(2″)-Ia, aadA1, bla(CMY-2), bla(CTX-M), bla(KPC-2), erm(B), mecA, tet(A), tet(B), and tet(M) genes was assessed by quantitative PCR. The tet(A) (2.9-log(2)-fold change, P = 0.04) and tet(B) (5.6-log(2)-fold change) ( P = 0.03) genes were significantly more abundant in RWA ground beef. Phylogenetic analyses revealed that ground beef microbiomes differed more by supplier than by production system. These results were consistent with prior research suggesting antimicrobial use in U.S. beef cattle has minimal impact on the AMR of bacteria found in these products. These results should spur a reevaluation of assumptions regarding the impact of antimicrobial use during U.S. beef production on the AMR of bacteria in ground beef. | 2018 | 30476443 |
| 2767 | 19 | 0.9834 | Characterisation of class 3 integrons with oxacillinase gene cassettes in hospital sewage and sludge samples from France and Luxembourg. In this study, antibiotic resistance class 3 integrons in Gram-negative bacteria isolated from hospital sewage and sludge and their genetic contents were characterised. Two samples of hospital effluent from France and Luxembourg and one sample of sludge from a wastewater treatment plant in France were collected in 2010 and 2011. Bacteria were cultured on selective agar plates and integrons were detected in colonies by quantitative PCR. Integron gene cassette arrays and their genetic environments were analysed by next-generation sequencing. Three class 3 integron-positive isolates were detected, including Acinetobacter johnsonii LIM75 (French hospital effluent), Aeromonas allosaccharophila LIM82 (sludge) and Citrobacter freundii LIM86 (Luxembourg hospital effluent). The gene cassettes were all implicated in antibiotic (aminoglycoside and β-lactam) or antiseptic resistance. An oxacillinase gene cassette (blaOXA-10, blaOXA-368 or blaOXA-2) was found in each integron. All of the class 3 integrons were located on small mobilisable plasmids. This study highlights the role of class 3 integrons in the dissemination of clinically relevant antibiotic resistance genes, notably oxacillinase genes, in hospital effluent. | 2016 | 27499434 |