Bacteria populating freshly appeared supraglacial lake possess metals and antibiotic-resistant genes. - Related Documents




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528101.0000Bacteria 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.202438262510
528010.9998High prevalence of antibiotic-resistant and metal-tolerant cultivable bacteria in remote glacier environment. Studies of antibiotic-resistant bacteria (ARB) have mainly originated from anthropic-influenced environments, with limited information from pristine environments. Remote cold environments are major reservoirs of ARB and have been determined in polar regions; however, their abundance in non-polar cold habitats is underexplored. This study evaluated antibiotics and metals resistance profiles, prevalence of antibiotic resistance genes (ARGs) and metals tolerance genes (MTGs) in 38 ARB isolated from the glacier debris and meltwater from Baishui Glacier No 1, China. Molecular identification displayed Proteobacteria (39.3%) predominant in debris, while meltwater was dominated by Actinobacteria (30%) and Proteobacteria (30%). Bacterial isolates exhibited multiple antibiotic resistance index values > 0.2. Gram-negative bacteria displayed higher resistance to antibiotics and metals than Gram-positive. PCR amplification exhibited distinct ARGs in bacteria dominated by β-lactam genes bla(CTX-M) (21.1-71.1%), bla(ACC) (21.1-60.5%), tetracycline-resistant gene tetA (21.1-60.5%), and sulfonamide-resistant gene sulI (18.4-52.6%). Moreover, different MTGs were reported in bacterial isolates, including mercury-resistant merA (21.1-63.2%), copper-resistant copB (18.4-57.9%), chromium-resistant chrA (15.8-44.7%) and arsenic-resistant arsB (10.5-44.7%). This highlights the co-selection and co-occurrence of MTGs and ARGs in remote glacier environments. Different bacteria shared same ARGs, signifying horizontal gene transfer between species. Strong positive correlation among ARGs and MTGs was reported. Metals tolerance range exhibited that Gram-negative and Gram-positive bacteria clustered distinctly. Gram-negative bacteria were significantly tolerant to metals. Amino acid sequences of bla(ACC,)bla(CTX-M,)bla(SHV,)bla(ampC,)qnrA, sulI, tetA and bla(TEM) revealed variations. This study presents promising ARB, harboring ARGs with variations in amino acid sequences, highlighting the need to assess the transcriptome study of glacier bacteria conferring ARGs and MTGs.202337858689
526220.9993High 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
527930.9993Occurrence of integrons and antibiotic resistance genes in cryoconite and ice of Svalbard, Greenland, and the Caucasus glaciers. The prevalence of integrons and antibiotic resistance genes (ARGs) is a serious threat for public health in the new millennium. Although commonly detected in sites affected by strong anthropogenic pressure, in remote areas their occurrence, dissemination, and transfer to other ecosystems is poorly recognized. Remote sites are considered as a benchmark for human-induced contamination on Earth. For years glaciers were considered pristine, now they are regarded as reservoirs of contaminants, thus studies on contamination of glaciers, which may be released to other ecosystems, are highly needed. Therefore, in this study we evaluated the occurrence and frequency of clinically relevant ARGs and resistance integrons in the genomes of culturable bacteria and class 1 integron-integrase gene copy number in the metagenome of cryoconite, ice and supraglacial gravel collected on two Arctic (South-West Greenland and Svalbard) and two High Mountain (the Caucasus) glaciers. Altogether, 36 strains with intI1 integron-integrase gene were isolated. Presence of class 1 integron-integrase gene was also recorded in metagenomic DNA from all sampling localities. The mean values of relative abundance of intI1 gene varied among samples and ranged from 0.7% in cryoconite from Adishi Glacier (the Caucasus) to 16.3% in cryoconite from Greenland. Moreover, antibiotic-resistant strains were isolated from all regions. Genes conferring resistance to β-lactams (bla(SHV), bla(TEM), bla(OXA), bla(CMY)), fluoroquinolones (qepA, qnrC), and chloramphenicol (cat, cmr) were detected in the genomes of bacterial isolates.202032059297
289040.9992Genetic diversity and antimicrobial resistance of Escherichia coli from Tagus estuary (Portugal). Fecal pollution of surface waters is a current world-wide public health concern and may contribute for the dissemination of antibiotic resistance. The Tagus estuary located in the south of Portugal is one of the largest wetlands in the west coast of Europe. In this study, water samples were collected from seven stations with different anthropic pressures along the estuary and evaluated for water quality indicator bacteria. Escherichia coli isolates (n=350) were typed by REP-PCR. Representatives of each REP profile (n=220) were evaluated phenotypically for resistance to 17 antibiotics and characterized in terms of phylogenetic group. Resistant isolates were screened for the presence of antibiotic resistance genes (tet(A), tet(B), sul1, sul2, qnrA, qnrB, qnrS, aacA4-cr, bla(TEM), bla(SHV), bla(CTX-M), bla(CMY-like), bla(IMP), bla(VIM)) and integrase genes (intI1 and intI2). The highest antibiotic resistance prevalence was observed for streptomycin and tetracycline followed by β-lactams and sulphonamides. Among E. coli isolates, 65.16% were resistant to at least one of the 17 antibiotics tested and approximately 19% were multiresistant. In our E. coli population phylo-groups A and D were predominant and characterized by higher prevalence of the antibiotic resistance. intI1 and intI2 genes were found in 12% of the isolates with prevalence of class 1 integrons. A strong correlation between the prevalence of integrons and multiresistance was observed. Differences in terms of antibiotic resistance between phylogenetic groups and between sampling sites were statistically significant. The results demonstrate a high prevalence of antibiotic resistance among E. coli circulating in the Tagus estuary with emphasis on the occurrence of resistance to last-resort antibiotics and on the high incidence of multiresistance.201323714246
275550.9992The Resistome of ESKAPEE Pathogens in Untreated and Treated Wastewater: A Polish Case Study. The aim of this study was to quantify ESKAPEE bacteria, genes encoding resistance to antibiotics targeting this group of pathogens, as well as integrase genes in municipal wastewater and river water. Environmental DNA was extracted from the collected samples and used in deep sequencing with the Illumina TruSeq kit. The abundance of bacterial genera and species belonging to the ESKAPEE group, 400 ARGs associated with this microbial group, and three classes of integrase genes were determined. A taxonomic analysis revealed that Acinetobacter was the dominant bacterial genus, whereas Acinetobacter baumannii and Escherichia coli were the dominant bacterial species. The analyzed samples were characterized by the highest concentrations of the following ARGs: bla(GES), bla(OXA-58), bla(TEM), qnrB, and qnrS. Acinetobacter baumannii, E. coli, and genes encoding resistance to β-lactams (bla(VEB-1), bla(IMP-1), bla(GES), bla(OXA-58), bla(CTX-M), and bla(TEM)) and fluoroquinolones (qnrS) were detected in samples of river water collected downstream from the wastewater discharge point. The correlation analysis revealed a strong relationship between A. baumannii (bacterial species regarded as an emerging human pathogen) and genes encoding resistance to all tested groups of antimicrobials. The transmission of the studied bacteria (in particular A. baumannii) and ARGs to the aquatic environment poses a public health risk.202236009054
537460.9992Molecular characterization of antibiotic resistance in cultivable multidrug-resistant bacteria from livestock manure. Diverse antibiotic-resistance genes (ARGs) are frequently reported to have high prevalence in veterinary manure samples due to extensive use of antibiotics in farm animals. However, the characteristics of the distribution and transmission of ARGs among bacteria, especially among different species of multiple antibiotic-resistant bacteria (MARB), have not been well explored. By applying high-throughput sequencing methods, our study uncovered a vast MARB reservoir in livestock manure. The genera Escherichia, Myroides, Acinetobacter, Proteus, Ignatzschineria, Alcaligenes, Providencia and Enterococcus were the predominant cultivable MARB, with compositions of 40.6%-85.7%. From chicken manure isolates, 33 MARB were selected for investigation of the molecular characteristics of antibiotic resistance. A total of 61 ARGs and 18 mobile genetic elements (MGEs) were investigated. We found that 47 ARGs were widely distributed among the 33 MARB isolates. Each isolate carried 27-36 genes responsible for resistance to eight classes of antibiotics frequently used in clinic or veterinary settings. ARGs to the six classes of antibiotics other than streptogramins and vancomycin were present in all 33 MARB isolates with a prevalence of 80%-100%. A total of 12 MGEs were widely distributed among the 33 MARB, with intI1, IS26, ISaba1, and ISEcp1 simultaneously present in 100% of isolates. In addition, 9 gene cassettes within integrons and ISCR1 were detected among MARB isolates encoding resistance to different antibiotic classes. This is the first report revealing the general co-presence of multiple ARGs, various MGEs and ARG cassettes in different species of individual MARB isolates in chicken manure. The results highlight a much higher risk of ARGs spreading through livestock manure to humans than we expected.201728599203
181070.9992Characterization of Metagenomes in Urban Aquatic Compartments Reveals High Prevalence of Clinically Relevant Antibiotic Resistance Genes in Wastewaters. The dissemination of antimicrobial resistance (AMR) is an escalating problem and a threat to public health. Comparative metagenomics was used to investigate the occurrence of antibiotic resistant genes (ARGs) in wastewater and urban surface water environments in Singapore. Hospital and municipal wastewater (n = 6) were found to have higher diversity and average abundance of ARGs (303 ARG subtypes, 197,816 x/Gb) compared to treated wastewater effluent (n = 2, 58 ARG subtypes, 2,692 x/Gb) and surface water (n = 5, 35 subtypes, 7,985 x/Gb). A cluster analysis showed that the taxonomic composition of wastewaters was highly similar and had a bacterial community composition enriched in gut bacteria (Bacteroides, Faecalibacterium, Bifidobacterium, Blautia, Roseburia, Ruminococcus), the Enterobacteriaceae group (Klebsiella, Aeromonas, Enterobacter) and opportunistic pathogens (Prevotella, Comamonas, Neisseria). Wastewater, treated effluents and surface waters had a shared resistome of 21 ARGs encoding multidrug resistant efflux pumps or resistance to aminoglycoside, macrolide-lincosamide-streptogramins (MLS), quinolones, sulfonamide, and tetracycline resistance which suggests that these genes are wide spread across different environments. Wastewater had a distinctively higher average abundance of clinically relevant, class A beta-lactamase resistant genes (i.e., bla(KPC), bla(CTX-M), bla(SHV), bla(TEM)). The wastewaters from clinical isolation wards, in particular, had a exceedingly high levels of bla(KPC-2) genes (142,200 x/Gb), encoding for carbapenem resistance. Assembled scaffolds (16 and 30 kbp) from isolation ward wastewater samples indicated this gene was located on a Tn3-based transposon (Tn4401), a mobilization element found in Klebsiella pneumonia plasmids. In the longer scaffold, transposable elements were flanked by a toxin-antitoxin (TA) system and other metal resistant genes that likely increase the persistence, fitness and propagation of the plasmid in the bacterial host under conditions of stress. A few bacterial species (Enterobacter cloacae, Klebsiella pneumoniae, Citrobacter freundii, Pseudomonas aeruginosa) that were cultured from the isolation ward wastewaters on CHROMagar media harbored the bla(KPC-2) gene. This suggests that hospital wastewaters derived from clinical specialty wards are hotspots for the spread of AMR. Assembled scaffolds of other mobile genetic elements such as IncQ and IncF plasmids bearing quinolone resistance genes (qnrS1, qnrS2) and the class A beta-lactamase gene (bla(TEM-1)) were recovered in wastewater samples which may aid the transfer of AMR.201729201017
530280.9992Antibiotic concentration and antibiotic-resistant bacteria in two shallow urban lakes after stormwater event. Stormwater runoff is generally characterized as non-point source pollution. In the present study, antibiotic concentration and antibiotic susceptibilities of cultivable heterotrophic bacteria were investigated in two small shallow urban lakes before and after strong storm event. Several antibiotics, lactose-fermenting bacteria and cultivable heterotrophic bacteria concentrations increased in surface water and/or surface sediment of two small urban lakes (Lake Xuanwu and Wulongtan) after strong storm event. In general, the frequencies of bacteria showing resistance to nine antibiotics increased after storm event. Based on the 16S rRNA genes of 50 randomly selected isolates from each water sample of two lakes, Aeromonas and Bacillus were dominant genera in samples from two lakes, while genera Proteus and Lysinibacillus were the third abundant genera in Lake Xuanwu and Wulongtu, respectively. Presences of nine antibiotic resistance genes (ARGs) in the 100 isolates were detected and most of these isolates harbored at least two ARGs with different functions. The detection frequency of ARGs in Gram-negative isolates was higher than that in Gram-positive isolates. The most prevalent integron in 100 isolates was int(II) (n = 28), followed by int(I) (n = 17) and int(III) (n = 17). Our results indicate that strong storm events potentially contribute to the transfer of ARGs and antibiotic-resistant bacteria from land-sewer system to the urban Lakes.201626865482
285890.9992Antibiotic resistance in fecal sludge and soil in Ho Chi Minh City, Vietnam. This study investigated the prevalence of antibiotic-resistant bacteria and genes in fecal sludge and soil in Ho Chi Minh City, Vietnam, and identified the factors contributing to the survival of antibiotic-resistant bacteria in soil. Sludge and soil samples (n = 24 and 55, respectively) were collected from residential septic systems and environmental reservoirs (i.e., canals, rivers, and parks) in twelve districts of Ho Chi Minh City and tested against a library of 12 antibiotic-resistant genes and 1 integron gene. The susceptibility of isolated Escherichia coli from sludge and soil (n = 104 and 129, respectively) was tested against nine antibiotics. Over 60% of sludge and soil samples harbored sul1, ere(A), intI1, cmIA, and tet(A) genes. The three most common phenotypic resistances found in E. coli isolated from sludge and soil were to ampicillin, tetracycline, and sulfamethoxazole/trimethoprim. In a temporal microcosm study of antibiotic-susceptible and multi-drug-resistant E. coli inoculated in soil, temperature (21.4 vs. 30 °C), resistance phenotype, and soil background microbial community were associated with E. coli decay rates over 73 days. This is the first study that provides insights into the high prevalence of antibiotic resistance in septic systems and environmental reservoirs in Ho Chi Minh City, Vietnam. Findings highlight that the fecal sludge and soil environments in Vietnam are likely reservoirs for dissemination of and human exposure to antibiotic resistance.201931643014
3515100.9992Impact of reclaimed water irrigation on antibiotic resistance in public parks, Beijing, China. The abundance and distribution of antibiotics and antibiotic resistance genes (ARGs) in soils from six parks using reclaimed water in Beijing, China, were characterized. Three classes of commonly used antibiotics (tetracycles, quinolones, and sulfonamides) were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The highest concentrations of tetracyclines and quinolones were 145.2 μg kg(-1) and 79.2 μg kg(-1), respectively. Detected tetG, tetW, sulI, and sulII genes were quantified by quantitative PCR. ARGs exhibited various abundances for different park soils. The integrase gene (intI1) as an indicator of horizontal gene transfer potential was also detected in high abundance, and had significant positive correlation with tetG, sulI, and sulII genes, suggesting that intI1 may be involved in ARGs dissemination. Both sulII and intI1 clones had high homology with some classes of pathogenic bacteria, such as Klebsiella oxytoca, Acinetobacter baumannii, Shigella flexneri, which could trigger potential public health concern.201424071635
5271110.9992Occurrence of Antibiotic-Resistant Bacteria and Genes in Two Drinking Water Treatment and Distribution Systems in the North-West Province of South Africa. With the increasing spread of antimicrobial resistance, there is growing attention to the contribution made by drinking water systems. The potential health impact of two drinking water treatment and distribution systems (A and B) in the North-West Province of South Africa was determined by investigating the water quality and occurrence of antimicrobial-resistant heterotrophic bacteria and genes in the raw and treated water over four seasons. Most of the physicochemical parameters except for electrical conductivity were within permissible limits. Coliform bacteria reduced from raw to potable water except for counts higher than the threshold recorded in Summer and Winter. A total of 203 heterotrophic bacterial isolates were recovered on chromogenic R2A medium and subjected to susceptibility testing to twelve antibiotics. Most of the isolates were resistant to β-lactam antibiotics and Trimethoprim, whereas they were susceptible to Ciprofloxacin, Erythromycin, and Neomycin. The proportions of Cephalothin and Kanamycin-resistant isolates were significantly higher (p < 0.05) after treatment for site A, compared to significantly lower β-lactam, Oxytetracycline, and Trimethoprim-resistant isolates for B. Over 50% of isolates were of high risk, indicating their origin from high antibiotic-use sources. Seventy-one (35%) isolates were multidrug-resistant, out of which the majority (53.5%, n = 38) possessed the strA gene, followed by strB 21 (29.6%), dfrB 13 (18.3%), aadA 11 (15.5%), bla(CTX-M) 5 (7.0%), and tetA 3 (4.2%). The 16S rRNA gene sequences of the isolates revealed strains belonging to eight bacterial families, some of which are clinically important.202033126462
3089120.9992Distribution characteristics of antibiotic resistance bacteria and related genes in urban recreational lakes replenished by different supplementary water source. The distribution characteristics of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in urban recreational water from different water-supply sources might be different. In this study, water samples were collected to detect the antibiotic resistance of heterotrophic bacteria to five antibiotics, and the content, phenotype, gene type and species distribution of resistant bacteria were analyzed. The results showed that the changes of bacteria resistance rate in two lakes to five kinds of antibiotics were synchronous with time, and it would reach its maximum in autumn. The detection of ARGs and int I in 80 resistance strains showed that the detection rate of tetG, tetA and int I was high. Here, 51.25% of the bacteria were doubly resistant to AMP-CTX. The 80 isolate strains were of nine genera and 19 species, among which Bacillus cereus, Escherichia coli, Aeromonas veronii, Aeromonas caviae and Raoultella ornithinolytica were the common ARB species in two lakes. Correlation analysis showed that the water temperature was significantly correlated with the content of ARB in sulfamethoxazole (SMZ) and cefotaxime (CTX) (p < 0.05), and the total phosphorus (TP) in FQ lake was significantly correlated with the content of AMP-resistant bacteria (p < 0.05), while there were no other correlations between the changes of other water quality indexes and the content of ARB (p > 0.05).202235228362
2842130.9992Assessing antimicrobial and metal resistance genes in Escherichia coli from domestic groundwater supplies in rural Ireland. Natural ecosystems can become significant reservoirs and/or pathways for antimicrobial resistance (AMR) dissemination, with the potential to affect nearby microbiological, animal, and ultimately human communities. This is further accentuated in environments that provide direct human exposure, such as drinking water. To date, however, few studies have investigated AMR dissemination potential and the presence of co-selective stressors (e.g., metals/metalloids) in groundwater environments of human health significance. Accordingly, the present study analysed samples from rural (drinking) groundwater supplies (i.e., private wells) in the Republic of Ireland, where land use is dominated by livestock grazing activities. In total, 48 Escherichia coli isolates tested phenotypically for antimicrobial susceptibility in an earlier study were further subject to whole genome sequencing (WGS) and corresponding water samples were further analysed for trace metal/metalloid concentrations. Eight isolates (i.e., 16.7%) were genotypically resistant to antimicrobials, confirming prior phenotypic results through the identification of ten antimicrobial resistance genes (ARGs); namely: aph(3″)-lb (strA; n=7), aph(6)-Id (strA; n = 6), blaTEM (n = 6), sul2 (n = 6), tetA (n = 4), floR (n = 2), dfrA5 (n = 1), tetB (n = 1), and tetY (n = 1). Additional bioinformatic analysis revealed that all ARGs were plasmid-borne, except for two of the six sul2 genes, and that 31.2% of all tested isolates (n = 15) and 37.5% of resistant ones (n = 3) carried virulence genes. Study results also found no significant relationships between metal concentrations and ARG abundance. Additionally, just one genetic linkage was identified between ARGs and a metal resistance gene (MRG), namely merA, a mercury-resistant gene found on the same plasmid as blaTEM, dfrA5, strA, strB, and sul2 in the only isolate of inferred porcine (as opposed to bovine) origin. Overall, findings suggest that ARG (and MRG) acquisition may be occurring prior to groundwater ingress, and are likely a legacy issue arising from agricultural practices.202337343911
5372140.9992Transfer potentials of antibiotic resistance genes in Escherichia spp. strains from different sources. Multidrug-resistant Escherichia coli and antibiotic-resistance genes (ARGs) present a danger to public health. However, information on the dissemination potentials of antibiotic resistance among bacteria from different environments is lacking. We isolated multiple antibiotic-resistant Escherichia spp. from animal farms, hospitals, and municipal wastewater-treatment plants (MWWTPs) using culture-based methods, and carried out resistance phenotype and gene analyses. Thirty-five isolates of multiple antibiotic-resistant Escherichia spp. were further screened to detect 61 ARGs, 18 mobile genetic elements (MGEs), and gene cassettes. The isolates from livestock manure and MWWTPs showed greater diversity in plasmid profiling than hospital wastewater. Each Escherichia sp. carried 21-26 ARGs and 8-12 MGEs. In addition, 11 gene cassettes were detected in 34 Escherichia isolates, with greater diversity in livestock manure and MWWTPs than in hospital wastewater. The results indicated that the potential for ARG transfer was higher in livestock manure and MWWTPs compared with human clinical sources, possibly related to the high occurrence of both residual antibiotics and heavy metals in these environments.202031896018
5340150.9992Hospital wastewaters: A reservoir and source of clinically relevant bacteria and antibiotic resistant genes dissemination in urban river under tropical conditions. The occurrence and dissemination of antibiotic resistant genes (ARGs) that are associated with clinical pathogens and the evaluation of associated risks are still under-investigated in developing countries under tropical conditions. In this context, cultivable and molecular approaches were performed to assess the dissemination of bacteria and the antibiotic resistance genes in aquatic environment in Kinshasa, Democratic Republic of the Congo. Cultivable approach quantified β-lactam, carbapenem resistant, and total Escherichia coli and Enterobacteriaceae in river sediments and surface waters that receive raw hospital effluents. The molecular approach utilized Quantitative Polymerase Chain Reaction (qPCR) to quantify the total bacteria and the richness of relevant bacteria (Escherichia coli, Enterococcus, and Pseudomonas), and antibiotic resistance genes (ARGs: bla(OXA-48), bla(CTX-M), bla(IMP), bla(TEM)) in sediment samples. Statistical analysis were employed to highlight the significance of hospital contribution and seasonal variation of bacteria and ARGs into aquatic ecosystems in suburban municipalities of Kinshasa, Democratic Republic of the Congo. The contribution of hospitals to antibiotic resistance proliferation is higher in the dry season than during the wet season (p < 0.05). Hospital similarly contributed Escherichia coli, Enterococcus, and Pseudomonas and ARGs significantly to the sediments in both seasons (p < 0.05). The organic matter content correlated positively with E. coli (r = 0.50, p < 0.05). The total bacterial load correlated with Enterococcus, and Pseudomonas (0.49 < r < 0.69, p < 0.05). Each ARG correlated with the total bacterial load or at least one relevant bacteria (0.41 < r < 0.81, p < 0.05). Our findings confirm that hospital wastewaters contributed significantly to antibiotic resistance profile and the significance of this contribution increased in the dry season. Moreover, our analysis highlights this risk from untreated hospital wastewaters in developing countries, which presents a great threat to public health.202032470679
3625160.9992Antibiotic resistant bacteria/genes dissemination in lacustrine sediments highly increased following cultural eutrophication of Lake Geneva (Switzerland). This study investigates faecal indicator bacteria (FIB), multiple antibiotic resistant (MAR), and antibiotic resistance genes (ARGs), of sediment profiles from different parts of Lake Geneva (Switzerland) over the last decades. MARs consist to expose culturable Escherichia coli (EC) and Enterococcus (ENT) to mixed five antibiotics including Ampicillin, Tetracycline, Amoxicillin, Chloramphenicol and Erythromycin. Culture-independent is performed to assess the distribution of ARGs responsible for, β-lactams (blaTEM; Amoxicillin/Ampicillin), Streptomycin/Spectinomycin (aadA), Tetracycline (tet) Chloramphenicol (cmlA) and Vancomycin (van). Bacterial cultures reveal that in the sediments deposited following eutrophication of Lake Geneva in the 1970s, the percentage of MARs to five antibiotics varied from 0.12% to 4.6% and 0.016% to 11.6% of total culturable EC and ENT, respectively. In these organic-rich bacteria-contaminated sediments, the blaTEM resistant of FIB varied from 22% to 48% and 16% to 37% for EC and ENT respectively, whereas the positive PCR assays responsible for tested ARGs were observed for EC, ENT, and total DNA from all samples. The aadA resistance gene was amplified for all the sediment samples, including those not influenced by WWTP effluent water. Our results demonstrate that bacteria MARs and ARGs highly increased in the sediments contaminated with WWTP effluent following the cultural eutrophication of Lake Geneva. Hence, the human-induced changing limnological conditions highly enhanced the sediment microbial activity, and therein the spreading of antibiotic resistant bacteria and genes in this aquatic environment used to supply drinking water in a highly populated area. Furthermore, the presence of the antibiotic resistance gene aadA in all the studied samples points out a regional dissemination of this emerging contaminant in freshwater sediments since at least the late nineteenth century.201222051343
2953170.9992Diverse Mobile Genetic Elements and Conjugal Transferability of Sulfonamide Resistance Genes (sul1, sul2, and sul3) in Escherichia coli Isolates From Penaeus vannamei and Pork From Large Markets in Zhejiang, China. High prevalence rates of sulfonamide resistance genes sul1, sul2, and sul3 have been observed in Gram-negative bacteria isolated from humans, domestic animals, and aquaculture species worldwide. We investigated the distribution characteristics, location, conjugative transferability, and genetic environments of sul genes from Escherichia coli isolates collected from Penaeus vannamei and pork samples from three large markets in Zhejiang, China. The prevalence rates of sul genes in sulfonamide-resistant E. coli isolates from P. vannamei and pork samples were 90.0 and 88.6%, respectively, and the prevalence of sul1 and sul2 was significantly higher than that of sul3 (p < 0.05). Twenty-four representative sul-positive E. coli isolates were analyzed in detail. Southern blot hybridization confirmed that sul genes of E. coli isolates were located on plasmids and/or chromosomes. Transfer of resistance through conjugation was observed in all 18 E. coli isolates harboring sul genes on plasmids. Replicon typing identified seven different incompatibility groups and IncF was the dominant replicon type among sul gene-containing plasmids from both sources. PCR walking analysis indicated that 87.5% (35/40) of sul gene-related fragments carried insertion sequences (ISs) belonging to a variety of families in diverse sites, with IS26 occurring most frequently. In addition, the sul1 gene was detected mainly in fragments carrying class 1 integrons. Co-location on the same fragment with resistance genes that may contribute to the persistence and dissemination of sul1 and/or sul2 genes. The diversity of mobile genetic elements and resistance genes adjacent to sul3 was much lower than those adjacent to sul1 and sul2, especially those located in chromosomes, which reduced the transmission potential of the sul3 gene. In conclusion, combined with the results of clonal relatedness analysis by PFGE and MLST of 24 representative E. coli isolates from P. vannamei and pork samples, it showed that a small number of sul genes were vertically transmitted among E. coli from P. vannamei and that horizontal gene transfer was likely the main transmission mechanism of sul genes from both sources. Our results provide important information to better understand the risk of transmission of sul genes from seafood and meat to humans.201931428076
5255180.9992Occurrence and removal of antibiotics, antibiotic resistance genes, and bacterial communities in hospital wastewater. Hospital wastewater contains a variety of human antibiotics and pathogens, which makes the treatment of hospital wastewater essential. However, there is a lack of research on these pollutants at hospital wastewater treatment plants. In this study, the characteristics and removal of antibiotics and antibiotic resistance genes (ARGs) in the independent treatment processes of hospitals of different scales (primary hospital, H1; secondary hospital, H2; and tertiary hospital, H3) were investigated. The occurrence of antibiotics and ARGs in wastewater from three hospitals varied greatly. The first-generation cephalosporin cefradine was detected at a concentration of 2.38 μg/L in untreated wastewater from H1, while the fourth-generation cephalosporin cefepime had the highest concentration, 540.39 μg/L, at H3. Ofloxacin was detected at a frequency of 100% and had removal efficiencies of 44.2%, 51.5%, and 81.6% at H1, H2, and H3, respectively. The highest relative abundances of the β-lactam resistance gene bla(GES-1) (1.77×10(-3) copies/16S rRNA), the quinolone resistance gene qnrA (8.81×10(-6) copies/16S rRNA), and the integron intI1 (1.86×10(-4) copies/16S rRNA) were detected in the treated wastewater. The concentrations of several ARGs were increased in the treated wastewater (e.g. bla(OXA-1), bla(OXA-10), and bla(TEM-1)). Several pathogenic or opportunistic bacteria (e.g. Acinetobacter, Klebsiella, Aeromonas, and Pseudomonas) were observed at high relative abundances in the treated wastewater. These results suggested the co-occurrence of antibiotics, ARGs, and antibiotic-resistant pathogens in hospital wastewater, and these factors may spread into the receiving aquatic environment.202134089156
2779190.9992Antibiotic resistance determinants among carbapenemase producing bacteria isolated from wastewaters of Kathmandu, Nepal. The emergence of carbapenem resistant bacteria (CRB) possesses a remarkable threat to the health of humans. CRB and carbapenem resistance genes (CRGs) have frequently been reported in clinical isolates from hospitals, however, their occurrence and distribution in wastewaters from various sources and river water have not been emphasized in Nepal. So, this study aimed to detect carbapenem resistant bacterial isolates and their resistance determinants in river water and different types of wastewaters. River water and both untreated and treated wastewater samples from hospitals, pharmaceutical industries, and municipal sewage were collected in summer and winter seasons. From 68 grab wastewater samples, CRB were detected only in 16 samples, which included eight hospital wastewater, and four each from untreated municipal sewage and river water. A total of 25 CRB isolates were detected with dominance of E. coli (44.0%) and K. pneumoniae (24.0%). The majority of the isolates harbored bla(NDM-1) (76.0%), followed by bla(OXA) (36.0%) and bla(KPC) (20.0%) genes. Hospital wastewater majorly contributed to the presence of bla(NDM-1), bla(KPC), and bla(OXA) along with intI1 genes compared to river water and untreated municipal sewage, especially during the winter season. However, CRB were not detected in treated effluents of hospitals and municipal sewage, and both influents and effluents from pharmaceutical industries. The combined presence of each bla(NDM-1) & bla(OXA) and bla(KPC) & bla(OXA) occurred in 16.0% of the bacterial isolates. The increased minimum inhibitory concentration (MIC) of meropenem was significantly associated with the presence of CRGs. The results of this study highlight the significance of carbapenem resistance in bacteria isolated from wastewater and river water, and underscore the necessity for efficient monitoring and control strategies to prevent the dispersion of carbapenem resistance in the environment and its potential consequences on human health.202438114055