Environmental antibiotic stress and high-risk resistance genes in bacterial communities of the Gomti and Ganga Rivers, India. - Related Documents




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527001.0000Environmental antibiotic stress and high-risk resistance genes in bacterial communities of the Gomti and Ganga Rivers, India. BACKGROUND: The river ecosystems provide habitats and source of water for a number of species including humans. The uncontrolled accumulation of pollutants in the aquatic environment enhances the development of antibiotic-resistant bacteria and genes. METHODS: Water samples were collected seasonally from different sites of Gomti and Ganga River. Bacteria were isolated by plating on nutrient agar supplemented with individual antibiotics (100 µg/ml) to select the resistant strains. These isolates were subsequently tested for cross-resistance to other antibiotics using the disc diffusion method. PCR was performed to detect selected ARGs. RESULTS: The enumeration of microbial population of Gomti River, the tetracycline-resistant bacteria comprised 38% of the bacterial population during spring and chloramphenicol resistance during autumn was a mere 11.9%. Nevertheless, erythromycin resistance was widespread amongst Ganga river bacteria during winter by 28%, while ciprofloxacin resistance was seen in autumn with only 15.8%. Bacterial population led to decline due to antibiotic-induced stress. The tetracycline-resistant bacteria were completely resistant to ampicillin and 66.6% were resistant to erythromycin. In Ganga river water, 53.5% of ampicillin-resistant isolates were resistant to erythromycin and sulphadiazine 93.3% were resistant to nalidixic acid. In the Gomti River water, the most common resistance gene among tetracycline resistant isolates was tetM (83.3%), followed by ampC (83.3%) in ampicillin-resistant isolates. In the Ganga River, 66.6% of bacterial isolates were found to have ampC and ermB genes. The sul1 gene was absent in all the bacterial isolates in both water samples. CONCLUSION: These findings indicate that both rivers act as reservoirs for multidrug-resistant bacteria harbouring complex resistance gene profiles.202540928717
527110.9999Occurrence 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
273520.9999Insight into the Antibiotic Resistance of Bacteria Isolated from Popular Aquatic Products Collected in Zhejiang, China. The present study was aimed to obtain a close insight into the distribution and diversity of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) among the aquatic products collected in Zhejiang, China. A total of 136 presumptive ARB picked up from six aquatic samples were classified into 22 genera and 49 species based on the 16S rDNA sequencing. Aeromonas spp., Shewanella spp., Acinetobacter spp., Myroides spp., Pseudomonas spp., and Citrobacter spp. accounted for 80% of the ARB. Among them, 109 isolates (80.15%) exhibited resistance to at least one antibiotic. Most isolates showed resistance to not only the originally selected drug but also to one to three other tested drugs. The diversity of ARB distributed in different aquatic products was significant. Furthermore, the resistance data obtained from genotypic tests were not entirely consistent with the results of the phenotypic evaluation. The genes qnrS, tetA, floR, and cmlA were frequently detected in their corresponding phenotypic resistant isolates. In contrast, the genes sul2, aac(6')-Ib, and bla (PSE) were less frequently found in the corresponding phenotypically resistant strains. The high diversity and detection rate of ARB and ARGs in aquaculture might be a significant threat to the food chains closely related to human health.202336929890
526930.9999Prevalence of antibiotic resistance genes in bacteria from Gomti and Ganga rivers: implications for water quality and public health. Rivers serve as a significant habitat and water sources for diverse organisms, including humans. An important environmental and public health concern is the increase in antibiotic-resistant bacteria (ARBs) and genes (ARGs) in aquatic ecosystems brought about by excessive pollutant flow. The research highlighted that river water, which is receiving discharge from wastewater treatment plants, is harbouring multidrug-resistant bacteria. River water samples were collected in January, April, July and October 2022 from three separate locations of each Gomti and Ganga river. A total of 114 bacteria were isolated from Gomti as well as the Ganga River. All the isolates were tested for their resistance to various antibiotics by disc diffusion method. The isolated bacteria were tested for the antibiotic resistance genes using PCR and were identified by 16s rRNA sequencing. The ARBs percentages for each antibiotic were as follows: ampicillin (100%); cefotaxime (96.4, 63.1%); erythromycin (52.6, 57.8%); amikacin (68.4, 50.8%); tetracycline (47.3, 54.3%); nalidixic acid (47.3, 45.6%); streptomycin (68.4, 49.1%); gentamycin (43.8, 35%); chloramphenicol (26.3, 33.3%); neomycin (49.1, 29.8%) and ciprofloxacin (24.5, 7.01%). Further, antibiotic resistance genes in Gomti and Ganga water samples disclose distinctive patterns, including resistance to ermB (25, 40%); tetM (25, 33.3%); ampC (44.4, 40%) and cmlA1 (16.6%). Notably cmlA1 resistant genes were absent in all bacterial strains of the Gomti River. Additionally, gyrA gene was not found in both the river water samples. The presence of ARGs in the bacteria from river water shows threat of transferring these genes to native environmental bacteria. To protect the environment and public health, constant research is necessary to fully understand the extent and consequences of antibiotic resistance in these aquatic habitats.202439349711
285440.9999Occurrence of antibiotic resistance genes in culturable bacteria isolated from Turkish trout farms and their local aquatic environment. Antibiotic resistance and presence of the resistance genes were investigated in the bacteria isolated from water, sediment, and fish in trout farms. A total of 9 bacterial species, particularly Escherichia coli, were isolated from the water and sediment samples, and 12 species were isolated from fish. The antimicrobial test indicated the highest resistance against sulfamethoxazole and ampicillin in coliform bacteria, and against sulfamethoxazole, imipenem, and aztreonam in known pathogenic bacteria isolated from fish. The most effective antibiotics were rifampicin, chloramphenicol, and tetracycline. The multiple antibiotic resistance index was above the critical limit for almost all of the bacteria isolated. The most common antibiotic resistance gene was ampC, followed by tetA, sul2, blaCTX-M1, and blaTEM in the coliform bacteria. At least one resistance gene was found in 70.8% of the bacteria, and 66.6% of the bacteria had 2 or more resistance genes. Approximately 36.54% of the bacteria that contain plasmids were able to transfer them to other bacteria. The plasmid-mediated transferable resistance genes were ampC, blaCTX-M1, tetA, sul2, and blaTEM. These results indicate that the aquatic environment could play an important role in the development of antibiotic resistance and the dissemination of resistance genes among bacteria.201525993887
285150.9999Detection of antibiotic resistance and tetracycline resistance genes in Enterobacteriaceae isolated from the Pearl rivers in South China. This study investigated antibiotic resistance profiles and tetracycline resistance genes in Enterobacteriaceae family isolates from the Pearl rivers. The Enterobacteriaceae isolates were tested for susceptibility to seven antibiotics ampicillin, chloramphenicol, ciprofloxacin, levofloxacin, sulphamethoxazole/trimethoprim, tetracycline and trimethoprim. In Liuxi reservoir, with an exception to ampicillin resistant strains (11%) no other antibiotic resistance bacterial strains were detected. However, multiple drug resistance in bacterial isolates from the other sites of Pearl rivers was observed which is possibly due to sewage discharge and input from other anthropogenic sources along the rivers. Four tetracycline resistance genes tet A, tet B, tet C and tet D were detected in the isolates from the rivers. The genes tet A and tet B were widely detected with the detection frequencies of 43% and 40% respectively. Ciprofloxacin and levofloxacin resistant enteric bacteria were also isolated from the pig and duck manures which suggest a wider distribution of human specific drugs in the environment. This investigation provided a baseline data on antibiotic resistance profiles and tetracycline resistance genes in the Pearl rivers delta.201020356660
526560.9999Prevalence of antibiotic-resistant fecal bacteria in a river impacted by both an antibiotic production plant and urban treated discharges. In this study, the abundance and spatial dynamics of antibiotic-resistant fecal bacteria (Escherichia coli, total coliforms and Enterococcus spp.) were determined in water and sediment samples from a river impacted by both antibiotic production plant (APP) and urban wastewater treatment plant (WWTP) discharges. Agar dilution and disk diffusion methods were also used for antimicrobial susceptibility testing. Two antimicrobial agents, cephalexin (25 μg/ml) and amoxicillin (50 μg/ml), were evaluated using the agar dilution method for E. coli, total coliforms (TC) and Enterococcus spp., whereas the degree of sensitivity or resistance of E. coli isolates to penicillin (10 U), ampicillin (10 μg), doxycycline (30 μg), tetracycline (30 μg), erythromycin (15 μg), azithromycin (15 μg) and streptomycin (10 μg) was performed using the disk diffusion method. Real-time PCR assays were used to determine the prevalence of three antibiotic-resistance genes (ARGs). The agar dilution method showed that most E. coli isolates and TC were resistant to amoxicillin, especially after receiving the APP discharges. Antibiotic resistances to amoxicillin and cephalexin were higher after the APP discharge point than after the WWTP effluent. The disk diffusion method revealed that 100% of bacterial isolates were resistant to penicillin and erythromycin. Multidrug-resistant bacteria were detected and showed a higher proportion at the WWTP discharge point than those in the APP. Highly multidrug-resistant bacteria (resistance to more than 4 antibiotics) were also detected, reaching mean values of 41.6% in water samples and 50.1% in sediments. The relative abundance of the blaTEM, blaCTX-M and blaSHV genes was higher in samples from the treatment plants than in those collected upstream from the discharges, especially for water samples collected at the APP discharge point. These results clearly demonstrate that both the APP and the WWTP contribute to the emergence and spread of antibiotic resistance in the environment.201424836130
293070.9998Prevalence of antibiotic resistance genes in the bacterial flora of integrated fish farming environments of Pakistan and Tanzania. The use of a wide variety of antimicrobials in human and veterinary medicine, including aquaculture, has led to the emergence of antibiotic resistant pathogens. In the present study, bacteria from water, sediments, and fish were collected from fish farms in Pakistan and Tanzania with no recorded history of antibiotic use. The isolates were screened for the presence of resistance genes against various antimicrobials used in aquaculture and animal husbandry. Resistant isolates selected by disk diffusion and genotyped by Southern hybridization were further screened by polymerase chain reaction (PCR) and amplicon sequencing. The prominent resistance genes identified encoded tetracycline [tetA(A) and tetA(G)], trimethoprim [dfrA1, dfrA5, dfrA7, dfrA12, and dfrA15], amoxicillin [bla(TEM)], streptomycin [strA-strB], chloramphenicol [cat-1], and erythromycin resistance [mefA]. The int1 gene was found in more than 30% of the bacterial isolates in association with gene cassettes. MAR indices ranged from 0.2 to 1. The bla(NDM-1) gene was not identified in ertapenem resistant isolates. It is hypothesized that integrated fish farming practices utilizing domestic farm and poultry waste along with antibiotic residues from animal husbandry may have contributed to a pool of resistance genes in the aquaculture systems studied.201222823142
285280.9998The emergence of antimicrobial resistance in environmental strains of the Bacteroides fragilis group. Anaerobic bacteria of the genus Bacteroides are a large group of commensal microorganisms that colonize the human and animal digestive tract. The genus Bacteroides and the closely related genus Parabacteroides include the Bacteroides fragilis group (BFG) of potentially pathogenic bacteria which are frequently isolated from patients with anaerobic infections. The aim of this study was to assess the antimicrobial resistance of environmental strains of the Bacteroides fragilis group. Strains were isolated from human feces, hospital wastewater, influent (UWW) and effluent (TWW) wastewater from a wastewater treatment plant (WWTP), and from the feces of lab rats as a negative control to monitor the entire route of transmission of BFG strains from humans to the environment. The resistance of 123 environmental BFG strains to six antibiotic groups was analyzed with the use of culture-dependent methods. Additionally, the presence of 25 genes encoding antibiotic resistance was determined by PCR. The analyzed environmental BFG strains were highly resistant to the tested antibiotics. The percentage of resistant strains differed between the analyzed antibiotics and was determined at 97.56% for ciprofloxacin, 49.59% for erythromycin, 44.71% for ampicillin, 35.77% for tetracycline, 32.52% for amoxicillin/clavulanic acid, 26.83% for chloramphenicol, 26.01% for clindamycin, 11.38% for moxifloxacin, and 8.94% for metronidazole. The highest drug-resistance levels were observed in the strains isolated from UWW and TWW samples. The mechanisms of antibiotic-resistance were determined in phenotypically resistant strains of BFG. Research has demonstrated the widespread presence of genes encoding resistance to chloramphenicol (100% of all chloramphenicol-resistant strains), tetracyclines (97.78% of all tetracycline-resistant strains), macrolides, lincosamides and streptogramins (81.97% of all erythromycin-resistant strains). Genes encoding resistance to β-lactams and fluoroquinolones were less prevalent. None of the metronidazole-resistant strains harbored the gene encoding resistance to nitroimidazoles. BFG strains isolated from UWW and TWW samples were characterized by the highest diversity of antibiotic-resistance genes and were most often drug-resistant and multidrug-resistant. The present study examines the potential negative consequences of drug-resistant and multidrug-resistant BFG strains that are evacuated with treated wastewater into the environment. The transmission of these bacteria to surface water bodies can pose potential health threats for humans and animals; therefore, the quality of treated wastewater should be strictly monitored.201930682596
286190.9998Antibiotic Resistance Profiles and Genomic Analysis of Endophytic Bacteria Isolates from Wild Edible Fungi in Yunnan. The use of antibiotics has led to the emergence of antibiotic resistance, posing significant challenges in the prevention, control, and treatment of microbial diseases, while threatening public health, the environment, and food safety. In this study, the antibiotic resistance phenotypes and genotypes of 56 endophytic bacteria isolates from three species of wild edible fungi in Yunnan were analyzed using the Kirby-Bauer disk diffusion method and PCR amplification. The results revealed that all isolates were sensitive to ofloxacin, but resistance was observed against 17 other antibiotics. Specifically, 55, 53, and 51 isolates exhibited resistance to amoxicillin, penicillin, and vancomycin, respectively. Antibiotic resistance gene (ARG) detection indicated that the sulfonamide sul1 gene had the highest detection rate (53.57%). Excluding the ARG that was not detected, the lowest detection rates were the sulfonamide sul2 and sul3 genes, both at 1.79%. Among six tetracycline resistance genes, only tetK and tetM were detected. For β-lactam antibiotics, blaTEM, blaVIM, and blaSHV genes were present, while blaOXA was absent. In aminoglycoside resistance genes, aadB was not detected, while detection rates for aac(3')-IIa, acrB, and aadA1 were 3.57%, 1.79%, and 37.5%, respectively. The chloramphenicol Cat gene was detected at a rate of 14.29%, whereas floR was absent. For polypeptide resistance, VanC was detected at 3.57%, with EmgrB not detected. All three quinolone genes were detected, with detection rates of 8.92% for GyrA, 39.29% for GyrB, and 37.5% for ParC. Through phylogenetic analysis, 12 isolates that are closely related to ten common foodborne pathogenic bacteria were further selected for whole-genome sequencing and assembly. Gene annotations revealed that each isolate contained more than 15 ARGs and over 30 virulence factors. Notably, the detection rate of antibiotic resistance phenotypes was higher than that of genotypes, highlighting the importance of studying phenotypic antibiotic resistance that lacks identifiable ARGs. This study enriches the research on endophytes in wild edible fungi and provides new data for microbial ecology and antibiotic resistance research. It also offers critical insights for monitoring microbial antibiotic resistance in wild edible fungi and potentially other food sources, contributing to more effective strategies for ecological protection, sustainable agricultural development, and public health security.202540005728
2929100.9998Occurrence of antibiotic resistance and characterization of resistance genes and integrons in Enterobacteriaceae isolated from integrated fish farms in South China. Antibiotics are still widely applied in animal husbandry to prevent diseases and used as feed additives to promote animal growth. This could result in antibiotic resistance to bacteria and antibiotic residues in animals. In this paper, Enterobacteriaceae isolated from four integrated fish farms in Zhongshan, South China were tested for antibiotic resistance, tetracycline resistance genes, sulfonamide resistance genes, and class 1 integrons. The Kirby-Bauer disk diffusion method and polymerase chain reaction (PCR) assays were carried out to test antibiotic susceptibility and resistance genes, respectively. Relatively high antibiotic resistance frequencies were found, especially for ampicillin (80%), tetracycline (52%), and trimethoprim (50%). Out of 203 Enterobacteriaceae isolates, 98.5% were resistant to one or more antibiotics tested. Multiple antibiotic resistance (MAR) was found highest in animal manures with a MAR index of 0.56. Tetracycline resistance genes (tet(A), tet(C)) and sulfonamide resistance genes (sul2) were detected in more than 50% of the isolates. The intI1 gene was found in 170 isolates (83.7%). Both classic and non-classic class 1 integrons were found. Four genes, aadA5, aadA22, dfr2, and dfrA17, were detected. To our knowledge, this is the first report for molecular characterization of antibiotic resistance genes in Enterobacteriaceae isolated from integrated fish farms in China and the first time that gene cassette array dfrA17-aadA5 has been detected in such fish farms. Results of this study indicated that fish farms may be a reservoir of highly diverse and abundant antibiotic resistant genes and gene cassettes. Integrons may play a key role in multiple antibiotic resistances posing potential health risks to the general public and aquaculture.201121975604
2736110.9998Characterization of Bacterial Communities and Their Antibiotic Resistance Profiles in Wastewaters Obtained from Pharmaceutical Facilities in Lagos and Ogun States, Nigeria. In Nigeria, pharmaceutical wastewaters are routinely disseminated in river waters; this could be associated with public health risk to humans and animals. In this study, we characterized antibiotic resistant bacteria (ARB) and their antibiotic resistance profile as well as screening for sul1 and sul2 genes in pharmaceutical wastewater effluents. Bacterial composition of the wastewater sources was isolated on non-selective media and characterized by the polymerase chain reaction (PCR) amplification of the 16S rRNA genes, with subsequent grouping using restriction fragment length polymorphism (RFLP) and sequencing. The antibiotics sensitivity profiles were investigated using the standard disk diffusion plate method and the minimum inhibitory concentrations (MICs) of selected antibiotics on the bacterial isolates. A total of 254 bacterial strains were isolated, and majority of the isolates were identified as Acinetobacter sp., Klebsiella pneumonia, Proteus mirabilis, Enterobacter sp. and Bacillus sp. A total of 218 (85.8%) of the bacterial isolates were multidrug resistant. High MICs values were observed for all antibiotics used in the study. The result showed that 31.7%, 21.7% and 43.3% of the bacterial isolates harbored sul1, sul2, and Intl1 genes, respectively. Pharmaceuticals wastewaters are potential reservoirs of ARBs which may harbor resistance genes with possible risk to public health.201829966226
2865120.9998Antibiotic resistance in soil and water environments. Seven locations were screened for antibiotic-resistant bacteria using a modified agar dilution technique. Isolates resistant to high levels of antibiotics were screened for r plasmids. Low-level resistance (25 micro g x ml(-1)) was widespread for ampicillin, penicillin, tetracycline, vancomycin and streptomycin but not for kanamycin. Resistant populations dropped sharply at high antibiotic levels, suggesting that intrinsic non-emergent mechanisms were responsible for the multiple drug resistance exhibited at low doses. Dairy farm manure contained significantly (P < 0.01) more (%) resistant bacteria than the other sites. Bacteria isolated from a dairy water canal, a lake by a hospital and a residential garden (fertilized by farm manure) displayed resistance frequencies of 77, 75 and 70%, respectively. Incidence of tetracycline resistance was most prevalent at 47-89% of total bacteria. Out of 200 representative isolates analyzed, Pseudomonas, Enterococcus-like bacteria, Enterobacter and Burkholderia species constituted the dominant reservoirs of resistance at high drug levels (50-170 micro g x ml(-1)). Plasmids were detected in only 29% (58) of these bacteria with tetracycline resistance accounting for 65% of the plasmid pool. Overall, resistance trends correlated to the abundance and type of bacterial species present in the habitat. Environmental reservoirs of resistance include opportunistic pathogens and constitute some public health concern.200212396530
2862130.9998Regulation Transcriptional of Antibiotic Resistance Genes (ARGs) in Bacteria Isolated from WWTP. The incidence of antibiotics and transcriptional regulation of ARGs in isolated bacteria from wastewater needs to be explored. By HPLC, in samples of untreated wastewater, ampicillin (49.74 ± 5.70 µg/mL), chloramphenicol (0.60 ± 0.03 µg/mL), tylosin (72.95 ± 2.03 µg/mL), and oxytetracycline (0.22 ± 0.01 µg/mL) was determined. Through metagenomic analysis identified 58 bacterial species belonging to 9 phyla and at least 14 species have shown resistance to a variety of antibiotics. Twenty-two bacterial isolates were proved to be resistant to fifteen antibiotics of new generation and used in medical research to combat infectious diseases. Fourteen strains were shown to harbor plasmids in size ranges of 2-5 Kb, 6-10 Kb and plasmids with size greater than 10 Kb. By quantitative PCR it was possible to identify genes sul, qnr, cat1, aadA1, and sat-1 gene were shown to be present in gDNA samples from treated and untreated samples of wastewater and by relative expression analysis, differential expression of cat1, ermB, act, and tetA genes was demonstrated in strains that showed identity with Escherichia coli, Bacteroides fragilis, and Salmonella thyphi, and that were stressed with different concentrations of antibiotics. The presence of ARGs in untreated water samples, as well as in bacterial isolates, was indicative that in these habitats there are microorganisms that can resist β-lactams, aminoglycosides, tetracyclines, sulfonamides, and quinolones.202337672120
2847140.9998Phenotypic and genotypic antimicrobial resistance patterns of Escherichia coli and Klebsiella isolated from dairy farm milk, farm slurry and water in Punjab, India. Antibiotic resistance is a mushrooming pandemic at national and international levels which if not controlled at this very moment, can lead to global problems. Main reason for emerging bacterial resistance is repeated exposure of bacteria to antimicrobial agents and access of bacteria to increasingly large pools of antimicrobial resistance genes in mixed bacterial populations. A total of 51 villages were sampled in the current study contributing to a total of 153 farms. A total of 612 samples comprising 153 each of raw pooled milk samples, slurry, animal drinking water and human drinking water were gathered from small, medium and large farms located in all seven tehsils of Ludhiana district of Punjab. In addition to that, 37 samples of village pond water were also collected from the targeted villages. Out of total 153 slurry, raw pooled milk samples, animal drinking water and human drinking water samples (each), the prevalence of 24.8%, 60%, 26.7% and 16.3% was found for E. coli respectively. On the other hand, for Klebsiella, the overall prevalence of 19.6%, 51%, 20.2% and 5.8% was found from slurry, raw pooled milk samples, animal drinking water and human drinking water respectively. In all matrices, the comparative frequency of resistance genes in positive isolates of E. coli and K. pneumoniae was: tetA > tetB > tetC, qnrS > qnrB > qnrA, sulII > sulI > sulIII. The highest proportion of resistance genes was found in slurry (193 genes) followed by milk (71 genes). The overall pattern of resistant genes was tetA > sulII > qnrS. In conclusion, data from the present study suggested that commensal E. coli and Klebsiella may act as reservoirs of antimicrobial drug resistance genes which may be mobilised into human populations and untreated animal waste may be considered an important source of resistant bacteria leading to environmental pollution.202133544346
2860150.9998Multi-drug resistance, integron and transposon-mediated gene transfer in heterotrophic bacteria from Penaeus vannamei and its culture environment. Multi-drug resistance (MDR) in bacteria is regarded as an emerging pollutant in different food production avenues including aquaculture. One hundred and sixty out of 2304 bacterial isolates from shrimp farm samples (n = 192) of Andhra Pradesh, India, were MDR. Based on biochemical identification and 16S rRNA sequencing, they were grouped into 35 bacterial species with the predominance of Vibrio parahaemolyticus (12.5%). The MDR isolates showed highest resistance toward oxytetracycline (89%) with more than 0.2 MAR (multiple antibiotic resistance), demonstrates a high-risk source. The most prevalent antibiotic-resistance gene (ARG) and mobile genetic element (MGE) detected were tetA (47.5%) and int1 (46.2%), respectively. In conjugation experiments, overall transfer frequency was found to be in the range of 1.1 × 10(-9) to 1.8 × 10(-3) with the transconjugants harbouring ARGs and MGEs. This study exposed the wide distribution of MDR bacteria in shrimp and its environment, which can further aggravate the already raised concerns of antibiotic residues in the absence of proper mitigation measures.202235066837
2864160.9998Case study on the soil antibiotic resistome in an urban community garden. Urban agricultural soils can be an important reservoir of antibiotic resistance, and have great food safety and public health indications. This study investigated antibiotic-resistant bacteria and antibiotic resistance genes in urban agricultural soils using phenotypic and metagenomic tools. In total, 207 soil bacteria were recovered from 41 soil samples collected from an urban agricultural garden in Detroit, MI, USA. The most prevalent antibiotic resistance phenotype demonstrated by Gram-negative bacteria was resistance to ampicillin (94.2%), followed by chloramphenicol (80.0%), cefoxitin (79.5%), gentamicin (78.4%) and ceftriaxone (71.1%). All Gram-positive bacteria were resistant to gentamicin, kanamycin and penicillin. Genes encoding resistance to quinolones, β-lactams and tetracyclines were the most prevalent and abundant in the soil. qepA and tetA, both encoding efflux pumps, predominated in the quinolone and tetracycline resistance genes tested, respectively. Positive correlation (P<0.05) was identified among groups of antibiotic resistance genes, and between antibiotic resistance genes and metal resistance genes. The data demonstrated a diverse population of antibiotic resistance in urban agricultural soils. Phenotypic determination together with soil metagenomics proved to be a valuable tool to study the nature and extent of antibiotic resistance in the environment.201829857032
2853170.9998Antibiotic resistance and virulence genes in coliform water isolates. Widespread fecal pollution of surface water may present a major health risk and a significant pathway for dissemination of antibiotic resistance bacteria. The River Rhine is one of the longest and most important rivers in Europe and an important raw water source for drinking water production. A total of 100 coliform isolates obtained from River Rhine (Germany) were examined for their susceptibility to seven antimicrobial agents. Resistances against amoxicillin, trimethoprim/sulfamethoxazole and tetracycline were detected in 48%, 11% and 9% of isolates respectively. The antibiotic resistance could be traced back to the resistance genes bla(TEM), bla(SHV), ampC, sul1, sul2, dfrA1, tet(A) and tet(B). Whereby, the ampC gene represents a special case, because its presence is not inevitably linked to a phenotypic antibiotic resistance. Multiple antibiotics resistance was often accompanied by the occurrence of class 1 or 2 integrons. E. coli isolates belonging to phylogenetic groups A and B1 (commensal) were more predominant (57%) compared to B2 and D groups (43%) which are known to carry virulent genes. Additionally, six E. coli virulence genes were also detected. However, the prevalence of virulence genes in the E. coli isolates was low (not exceeding 4.3% per gene) and no diarrheagenic E. coli pathotypes were detected. This study demonstrates that surface water is an important reservoir of ARGs for a number of antibiotic classes such as sulfonamide, trimethoprim, beta-lactam-antibiotics and tetracycline. The occurrence of antibiotic resistance in coliform bacteria isolated from River Rhine provides evidence for the need to develop management strategies to limit the spread of antibiotic resistant bacteria in aquatic environment.201627497615
2869180.9998Antibiotic resistance and antibiotic-resistance genes of Pseudomonas spp. and Escherichia coli isolated from untreated hospital wastewater. Hospitals are considered an important factor in the spread of antibiotic-resistant bacteria (ARBs) and antibiotic-resistance genes (ARGs). The purpose of this research was to characterize the microbial populations in hospital wastewater and investigated the prevalence of β-lactamase, SulІ and QnrS resistance genes. In the first step, culture method was used to isolate Pseudomonas aeruginosa and Escherichia coli. In the next step, accurate identification of isolated bacteria was carried out using the polymerase chain reaction (PCR) method, then the resistance of the bacteria at different concentrations of antibiotics (8-128 μg/mL) was examined. Finally the ARGs were detected using the PCR method. The averages of heterotrophic plate count (HPC) and ARB concentration in wastewater samples were 1.8 × 10(8) and 4.3 × 10(6) CFU/100 mL, respectively. The highest resistance rates were found for sulfamethoxazole and the highest resistance rates in the β-lactamase group were for ceftazidime, while highest sensitivity was for gentamicin and there was no isolate that was sensitive to the studied antibiotics. SulІ and QnrS were the highest and lowest abundance of all ARGs in samples respectively and blaSHV was the highest β-lactam resistance gene. Our results indicated an increase in the resistance of identified bacteria to several antibiotics. So it can be concluded that numerous antibiotic-resistant pathogens and vast numbers of ARGs exist in the human body so that their release from hospitals without effective treatment can cause many dangers to the environment and human health.202134280162
2931190.9998Molecular characterization of antibiotic resistance in Escherichia coli strains from a dairy cattle farm and its surroundings. BACKGROUND: This study describes the phenotypic and genotypic characteristics of 78 genetically different Escherichia coli recovered from air and exudate samples of a dairy cattle farm and its surroundings in Spain, in order to gain insight into the flow of antimicrobial resistance through the environment and food supply. RESULTS: Antimicrobial resistance was detected in 21.8% of the 78 E. coli isolates analyzed (resistance for at least one of the 14 agents tested). The highest resistance rates were recorded for ampicillin, nalidixic acid, trimethoprim/sulfamethoxazole and tetracycline. The resistance genes detected were as follows (antibiotic (number of resistant strains), gene (number of strains)): ampicillin (9), bla(TEM-1) (6); tetracycline (15), tet(A) (7), tet(B) (4), tet(A) + tet(B) (1); chloramphenicol (5), cmlA (2), floR (2); trimethoprim/sulfamethoxazole (10), sul2 (4), sul1 (3), sul3 (2), sul1 + sul2 (1); gentamicin-tobramycin (1), ant(2″) (1). About 14% of strains showed a multidrug-resistant phenotype and, of them, seven strains carried class 1 integrons containing predominantly the dfrA1-aadA1 array. One multidrug-resistant strain was found in both inside and outside air, suggesting that the airborne spread of multidrug-resistant bacteria from the animal housing facilities to the surroundings is feasible. CONCLUSIONS: This study gives a genetic background of the antimicrobial resistance problem in a dairy cattle farm and shows that air can act as a source for dissemination of antimicrobial-resistant bacteria. © 2016 Society of Chemical Industry.201726969806