The diversity in antimicrobial resistance of MDR Enterobacteriaceae among Chinese broiler and laying farms and two mcr-1 positive plasmids revealed their resistance-transmission risk. - Related Documents




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295101.0000The diversity in antimicrobial resistance of MDR Enterobacteriaceae among Chinese broiler and laying farms and two mcr-1 positive plasmids revealed their resistance-transmission risk. This research aimed to investigate the microbial composition and diversity of antimicrobial resistance genes (ARGs) found in Chinese broiler and layer family poultry farms. We focused on the differences in resistance phenotypes and genotypes of multidrug-resistant Enterobacteriaceae (MDRE) isolated from the two farming environments and the existence and transmissibility of colistin resistance gene mcr-1. Metagenomic analysis showed that Firmicutes and Bacteroides were the dominant bacteria in broiler and layer farms. Many aminoglycoside and tetracycline resistance genes were accumulated in these environments, and their absolute abundance was higher in broiler than in layer farms. A total of 526 MDRE were isolated with a similar distribution in both farms. The results of the K-B test showed that the resistance rate to seven antimicrobials including polymyxin B and meropenem in broiler poultry farms was significantly higher than that in layer poultry farms (P ≤ 0.05). PCR screening results revealed that the detection rates of mcr-1, aph(3')Ia, aadA2, bla (oxa-1) , bla (CTX-M) , fosB, qnrD, sul1, tetA, and catA1 in broiler source MDRE were significantly higher than those in layers (P ≤0.05). A chimeric plasmid p20432-mcr which carried the novel integron In1866 was isolated from broiler source MDRE. The high frequency of conjugation (10(-1) to 10(-3)) and a wide range of hosts made p20432-mcr likely to play an essential role in the high detection rate of mcr-1, aph(3')-Ia, and aadA2 in broiler farms. These findings will help optimize disinfection and improve antimicrobial-resistant bacteria surveillance programs in poultry farms, especially broilers.202235992687
295310.9998Diverse 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
295220.9998Characterization of Integrons and Sulfonamide Resistance Genes among Bacteria from Drinking Water Distribution Systems in Southwestern Nigeria. BACKGROUND: The emergence of antibiotic resistance among pathogenic bacteria in clinical and environmental settings is a global problem. Many antibiotic resistance genes are located on mobile genetic elements such as plasmids and integrons, enabling their transfer among a variety of bacterial species. Water distribution systems may be reservoirs for the spread of antibiotic resistance. MATERIALS AND METHODS: Bacteria isolated from raw, treated, and municipal tap water samples from selected water distribution systems in south-western Nigeria were investigated using the point inoculation method with seeded antibiotics, PCR amplification, and sequencing for the determination of bacterial resistance profiles and class 1/2 integrase genes and gene cassettes, respectively. RESULTS: sul1,sul2, and sul3 were detected in 21.6, 27.8, and 0% of the isolates, respectively (n = 162). Class 1 and class 2 integrons were detected in 21.42 and 3.6% of the isolates, respectively (n = 168). Genes encoding resistance to aminoglycosides (aadA2, aadA1, and aadB), trimethoprim (dfrA15, dfr7, and dfrA1), and sulfonamide (sul1) were detected among bacteria with class 1 integrons, while genes that encodes resistance to strepthothricin (sat2) and trimethoprim (dfrA15) were detected among bacteria with class 2 integrons. CONCLUSIONS: Bacteria from these water samples are a potential reservoir of multidrug-resistant traits including sul genes and mobile resistance elements, i.e. the integrase gene.201727322615
293230.9998Resistance to Sulfonamides and Dissemination of sul Genes Among Salmonella spp. Isolated from Food in Poland. Antimicrobial resistance of pathogenic bacteria, including Salmonella spp., is an emerging problem of food safety. Antimicrobial use can result in selection of resistant organisms. The food chain is considered a route of transmission of resistant pathogens to humans. In many European countries, sulfonamides are one of the most commonly used antimicrobials. The aim of our investigation was to assess the prevalence of sul genes and plasmid occurrence among sulfonamide-resistant Salmonella spp. Eighty-four sulfonamide-resistant isolates were collected in 2008 and 2013 from retail products in Poland. Minimal inhibitory concentration of all of these isolates was ≥1024 μg/mL. Resistant isolates were tested for the presence of sul1, sul2, sul3, and int1 genes by using multiplex polymerase chain reaction. In total, 44.0% (37/84) isolates carried the sul1 gene, 46.4% (39/84) were sul2 positive, while the sul3 gene was not detected in any of the sulfonamide-resistant isolates tested. It was found that 3.6% (3/84) of resistant Salmonella spp. contained sul1, sul2, and intI genes. All 33 intI-positive isolates carried the sul1 gene. Eleven of the sulfonamide-resistant isolates were negative for all the sul genes. Most of the sulfonamide-resistant Salmonella spp. harbored plasmids; only in eight isolates were no plasmids detected. Generally, the size of the plasmids ranged from approximately 2 kb to ≥90 kb. Our results revealed a relatively a high prevalence of sulfonamides-resistant Salmonella spp. isolated from retail food. Additionally, we have detected a high dissemination of plasmids and class 1 integrons that may enhance the spread of resistance genes in the food chain.201525785781
295040.9998High rate of multidrug resistance and integrons in Escherichia coli isolates from diseased ducks in select regions of China. With the increasing number of ducks being raised and consumed, it is crucial to monitor the presence of multidrug resistant (MDR) bacteria in duck farming. Waterfowl, such as ducks, can contribute to the rapid dissemination of antibiotic resistance genes (ARGs). The objective of this study was to investigate the antimicrobial resistance (AMR), ARGs, and mobile genetic elements (MGEs), such as IS26, tbrC, ISEcp1 in Escherichia coli(E. coli) isolated from the intestinal contents of diseased ducks between 2021 and 2022 in Sichuan, Chongqing and Anhui, China. The AMR phenotypes of 201 isolated E. coli strains were determined using the minimum inhibitory concentrations (MICs) method. Subsequently, polymerase chain reaction and sequencing techniques were employed to screen for integron-integrase genes (intI1, intI2, intI3 genes), gene cassettes (GCs), MGEs, and ARGs. The results demonstrated that 96.5% of the E. coli isolates were resistant to at least 1 antibiotic, with 88.1% of the strains displaying MDR phenotype. The highest AMR phenotype observed was for trimethoprim-sulfamethoxazole (88.1%). Furthermore, class 1 and class 2 integrons were detected in 68.2% and 3.0% of all the isolates, respectively, whereas no class 3 integrons were found. Ten types of GCs were identified in the variable regions of class 1 and class 2 integrons. Moreover, 10 MGEs were observed in 46 combinations, with IS26 exhibiting the highest detection rate (89.6%). Among the 22 types of ARGs, tetA (77.1%) was the most frequently detected. In the conjugational transfer experiment, transconjugants were found to carry specific ARGs and MGEs, with their MIC values were significantly higher than those of recipient E. coli J53, indicating their status as MDR bacteria. This study emphasizes the necessity of monitoring MGEs, ARGs, and integrons in duck farms. It provides valuable insights into the complex formation mechanisms of AMR and may aid in preventing and controlling the spread of MDR bacteria in waterfowl breeding farm.202337586192
294850.9998Fecal cultivable aerobic microbiota of dairy cows and calves acting as reservoir of clinically relevant antimicrobial resistance genes. Antimicrobial resistance has become a global threat to public health since multidrug-resistant (MDR) bacteria have been reported worldwide carrying different antimicrobial resistance genes (ARGs), and animals have been described as a reservoir of ARGs. The presence of antimicrobial-resistant bacteria and ARGs in the food matrix is a risk to public health. This study aimed to research the presence of clinically relevant ARGs for important antimicrobials and genetic elements in fecal samples from dairy cows and calves on a Brazilian farm. In this study, a total of 21 fecal samples were collected, and then, the DNA of cultivable aerobic bacteria was extracted. Fifty-seven ARGs and twenty-three genetic elements were researched by PCR and confirmed by sequencing. Several ARGs that confer resistance to β-lactams, tetracyclines, fluoroquinolones, sulphonamides, phenicols, aminoglycoside, glycopeptides, and macrolides were detected. A total of 200 amplicons from 23 ARGs (bla(CTX-M-Gp2), bla(CMY), bla(SHV), tetA, tetB, tetC, qepA, qnrB, qnrS, oqxA, oqxB, vanC1, vanC2/3, aadA, sul1, sul2, sul3, ermB, mefAE, floR, cmlA, aadA, aph(3')-Ia, aac(3')-Ia), and 145 amplicons from 12 genetic elements (IncF, IncFIA, IncFIB, IncI1, IncY, IncU, IncK, IncP, IncR, IncHI1, ColE-like, intI1) were detected. The results presented in this study call attention to the monitoring of antimicrobial resistance in dairy farms worldwide. MDR bacteria and ARGs can spread to different sources, including milk products, which are one of the most consumed products worldwide, representing a potential risk to human health.202032246396
136360.9998Comparison of antimicrobial resistance and molecular characterization of Escherichia coli isolates from layer breeder farms in Korea. In Korea, 4 big layer companies that possess one grandparent and 3 parent stocks are in charge of 100% of the layer chicken industry. In this study, we investigated the antimicrobial resistance of commensal 578 E. coli isolated from 20 flocks of 4-layer breeder farms (A, B, C, and D), moreover, compared the characteristics of their resistance and virulence genes. Isolates from farms B and D showed significantly higher resistance to the β-lactam antimicrobials (amoxicillin, ampicillin, and 1st-, 2nd-, and 3rd-generation cephalosporins). However, resistance to ciprofloxacin, nalidixic acid, and tetracycline was significantly higher in the isolates from farm A (P < 0.05). Interestingly, the isolates from farm C showed significantly lower resistance to most antimicrobials tested in this study. The isolates from farms B, C, and D showed the high multiple resistance to the 3 antimicrobial classes. Furthermore, the isolates from farm A showed the highest multiple resistance against the 5 classes. Among the 412 β-lactam-resistant isolates, 123 (29.9%) carried bla(TEM-1), but the distribution was significantly different among the farms from 17.5% to 51.4% (P < 0.05). Similarly, the most prevalent tetracycline resistance gene in the isolates from farms B, C, and D was tetA (50.0-77.0%); however, the isolates from farm A showed the highest prevalence in tetB (70.6%). The distribution of quinolone (qnrB, qnrD, and qnrS) and sulfonamide (su12)-resistant genes were also significantly different among the farms but that of chloramphenicol (catA1)- and aminoglycoside (aac [3]-II, and aac [6']-Ib)-resistant genes possessed no significant difference among the farms. Moreover, the isolates from farm C showed significantly higher prevalence in virulence genes (iroN, ompT, hlyF, and iss) than the other 3 farms (P < 0.05). Furthermore, the phenotypic and genotypic characteristics of E. coli isolates were significantly different among the farms, and improved management protocols are required to control of horizontal and vertical transmission of avian disease, including the dissemination of resistant bacteria in breeder flocks.202234844113
289070.9998Genetic 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
136180.9998Multi-drug resistance and diversity of mobile genetic elements in Escherichia coli isolated from migratory bird in Poyang Lake. With the spread of antibiotic resistance genes such as blaCTX-M-2, dfrA1 and blaNDM-1, the problem of drug resistance in E. coli is becoming increasingly serious [1]. This study aimed to identify integrons genes and MGEs in E. coli isolated from migratory birds' feces at Poyang Lake, Jiangxi Province, focusing on their role in antimicrobial resistance (AMR). The 114 isolated E. coli strains were tested by standard disk diffusion method and genetic testing method. Results showed 64.04 % (73/114) of isolates were multi-drug resistance (MDR), mainly resistant to 3-6 antibiotics. Common resistances included neomycin (50 %) and streptomycin (48.25 %). We detected 21 mobile genetic elements, including IS903 (92.11 %), traA (72.81 %), ISCR3 (64.91 %), and ISpa7 (50 %). These elements were present in all isolates, forming 112 combinations. Significant differences in resistance rates were found between class I integron-positive and negative strains for doxycycline, tetracycline, bacitracin, and streptomycin (P < 0.01), and for neomycin (P < 0.05). Class II integron-positive bacteria showed higher resistance to doxycycline (P < 0.01) and ceftizoxime (P < 0.05). No significant differences were observed for class III integron-positive strains. This study underscores the prevalence of multidrug-resistant and the diversity of mobile genetic elements in E. coli, emphasizing the need for continuous monitoring.202540651621
273590.9998Insight 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
5271100.9998Occurrence 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
2929110.9998Occurrence 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
2931120.9998Molecular 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
2949130.9998Genomic analysis of multidrug-resistant Escherichia coli strains carrying the mcr-1 gene recovered from pigs in Lima-Peru. Antibiotic resistance is a current problem that significantly impacts overall health. The dissemination of antibiotic resistance genes (ARGs) to urban areas primarily occurs through ARG-carrying bacteria present in the gut microbiota of animals raised in intensive farming settings, such as pig production. Hence, this study aimed to isolate and analyzed 87 Escherichia coli strains from pig fecal samples obtained from intensive farms in Lima Department. The isolates were subjected to Kirby-Bauer-Disk Diffusion Test and PCR for mcr-1 gene identification. Disk-diffusion assay revealed a high level of resistance among these isolates to oxytetracycline, ampicillin, cephalothin, chloramphenicol, ciprofloxacin, and doxycycline. PCR analysis identified the mcr-1 gene in 8% (7/87) E. coli isolates. Further, whole genome sequencing was conducted on 17 isolates, including multidrug resistance (MDR) E. coli and/or mcr-1 gene carriers. This analysis unveiled a diverse array of ARGs. Alongside the mcr-1 gene, the bla(CTX-M55) gene was particularly noteworthy as it confers resistance to third generation cephalosporins, including ceftriaxone. MDR E. coli genomes exhibited other ARGs encoding resistance to fosfomycin (fosA3), quinolones (qnrB19, qnrS1, qnrE1), tetracyclines (tetA, tetB, tetD, tetM), sulfonamides (sul1, sul2, sul3), amphenicols (cmlA1, floR), lincosamides (inuE), as well as various aminoglycoside resistance genes. Additionally, Multi Locus Sequence Typing (MLST) revealed a high diversity of E. coli strains, including ST10, a pandemic clone. This information provides evidence of the dissemination of highly significant ARGs in public health. Therefore, it is imperative to implement measures aimed at mitigating and preventing the transmission of MDR bacteria carrying ARGs to urban environments.202337473695
2924140.9998Molecular characterization of selected multidrug resistant Pseudomonas from water distribution systems in southwestern Nigeria. BACKGROUND: Persistence of antibiotic resistant bacteria, including multidrug resistant (MDR) pseudomonads, is an important environmental health problem associated with drinking water distribution systems (DWDS) worldwide. There is paucity of data on the molecular characteristics of antibiotic resistance genes and their mode of transfer among pseudomonads from DWDS located in resource-challenged areas such as southwestern Nigeria. METHODS: MDR pseudomonads (n = 22) were selected from a panel of 296 different strains that were isolated from treated and untreated water in six DWDS located across southwest Nigeria. Primarily, the isolated pseudomonads strains were identified by 16S rDNA sequencing and antibiotic-resistance testing was completed using agar breakpoints assays. The final panel of strains of resistant to more than three classes of antibiotics (i.e. MDR), were further characterized by PCR genotyping, Sanger sequencing, and plasmid profiling. RESULTS: Pseudomonad resistance to gentamicin and streptomycin ranged from 22.7 to 54.6 % while resistance to tetracycline, ceftiofur and sulphamethoxazole ranged from 40.9 to 77.3 %. The most commonly detected antibiotic resistance genes were tet(A) (31.8 % of isolates), sul1 (31.8 %), bla TEM (40.9 %) and aph(3″) (c) (36.4 %). Class 1 integron sequences were evident in 27.3 % of isolates and they harbored genes encoding resistance to aminoglycosides (aadA2, aadA1), trimethoprim (dfrA15, dfr7) and sulphonamide (sul1) while the plasmid ranged between 22 and 130 kb. CONCLUSIONS: Pseudomonas spp, isolated from these DWDS possess resistance genes and factors that are of public and environmental health significance. Therefore, has the potential of contributing to the global scourge of resistance genes transfer in human, animals and environments, thereby, useful in the epidemiology of antimicrobial resistance.201526328550
5267150.9998Diversity and antibiotic resistance of cultivable bacteria in bulk tank milk from dairy farms in Shandong Province, China. INTRODUCTION: This study systematically analyzed bacterial diversity and antimicrobial resistance (AMR) profiles in bulk tank milk from five dairy farms (n = 30) in Shandong Province, China, to assess public health risks associated with microbial contamination and provide critical data for regional quality control and AMR risk assessment in dairy production systems. METHODS: Total bacterial counts were quantified, revealing significant inter-farm variation (P < 0.05) with a range of 3.94-6.68 log CFU/mL. Among 129 bacterial isolates, genus-level dominance and species prevalence were identified. Antimicrobial susceptibility testing (AST) against 10 agents was performed using integrated resistance criteria combining Clinical and Laboratory Standards Institute (CLSI) standards and epidemiological cutoff values (ECOFFs). Nine resistance genes targeting seven antibiotic classes were detected via PCR. RESULTS: The highest resistance rate was observed for sulfadiazine (53.2%) and the lowest for levofloxacin (6.0%). Multidrug resistance was detected in 23% (20/87) of isolates, with 14 strains meeting ECOFFs-based resistance criteria. PCR analysis showed sul1 (70.5%) and ant(4')-Ia (54.3%) as the most prevalent resistance genes, while mcr-1, lnu (B), and bla (NDM-1) were absent in all isolates. Regional resistance variations correlated significantly with farm management practices. DISCUSSION: These findings underscore the impact of historical antibiotic use on AMR dissemination. Enhanced AMR surveillance in raw milk, improved antibiotic stewardship, and targeted interventions are crucial to mitigate public health risks from microbial contamination and horizontal gene transfer of resistance determinants.202540771950
1368160.9998Prevalence and characterisation of antimicrobial resistance genes and class 1 and 2 integrons in multiresistant Escherichia coli isolated from poultry production. A global increase in the populations of drug resistant bacteria exerts negative effects on animal production and human health. Our study has been focused on the assessment of resistance determinants in relation to phenotypic resistance of the 74 commensal E. coli isolates present in different ecological environments. The samples were collected from poultry litter, feces, and neck skin. Among the microorganisms isolated from the poultry litter (group A), the highest resistance was noted against AMP and DOX (100%). In the E. coli extracts from the cloacal swabs (group B), the highest resistance was observed against AMP (100%) and CIP (92%). The meat samples (group C) were characterized by resistance to AMP (100%) and STX (94.7%). Genes encoding resistance to β-lactams (bla(TEM), bla(CTX-M)), fluoroquinolones (qnrA, qnrB, qnrS), aminoglycosides (strA-strB, aphA1, aac(3)-II), sulfonamides (sul1, sul2, sul3), trimethoprim (dfr1, dfr5, dfr7/17) and tetracyclines (tetA, tetB) were detected in the studied bacterial isolates. The presence of class 1 and 2 integrons was confirmed in 75% of the MDR E. coli isolates (plasmid DNA), of which 60% contained class 1 integrons, 15% contained class 2 integrons, and 11.7% carried integrons of both classes. Thus, it may be concluded that integrons are the common mediators of antimicrobial resistance among commensal multidrug resistant Escherichia coli at important stages of poultry production.202235410349
5268170.9998Occurrence of emerging sulfonamide resistance (sul1 and sul2) associated with mobile integrons-integrase (intI1 and intI2) in riverine systems. Global use of antibiotics has exceedingly enhanced in agricultural, veterinary and prophylactic human use in recent days. Hence, these antibiotics can easily be found in the environment. This study revealed the occurrence of emerging MDR and ESBL producing strains, pollution profile, and factors integrons (intI1 and intI2) and environmental factors associated, in the riverine systems under different ecological and geo-climatic zones were investigated. The samples were collected based on anthropogenic intervention such as discharge of domestic wastes, industrial wastes, hospital, and municipal wastes. Among 160bacterial morphotypes, 121 (75.62%) exhibited MDR trait with maximum resistance towards lincosamide (CD = 71.3%), beta-lactams (P = 70.6%; AMX = 66.3%), cephalosporin (CZ = 60.6%; CXM = 34.4%), sulfonamide (COT = 50.6%; TR = 43.8%) followed by macrolide (E = 29.4%), tetracycline (TET = 18.8%), aminoglycosides (S = 18.8%; GEN = 6.3%), fluoroquinolones (NX = 18.1%; OF = 4.4%) and carbapenem (IPM = 5.0%). IntI1 gene was detected in 73 (60.3%) of isolates, whereas intI2 was found in 11 (9.09%) isolates. Eight (6.61%) isolates carried both integron genes (intI1 and intI2). sul1 and dfrA1 genes were detected in 53 (72.6%) and 63 (86.3%) isolates, respectively. A total of 103 (85.1%) were found ESBL positive with the presence of ESBL genes in 100 (97.08%) isolates. In riverine systems most prevalent ESBL gene blaTEM (93.0%) was detected alone as well as in combination with bla genes. The data can be utilized for public awareness and regulation of guidelines by local governing bodies as an alarming threat to look-out against the prevalent resistance in environment thereby assisting in risk management during epidemics. This study is a comprehensive investigation of emerging antibiotic pollutants and its resistance in bacteria associated with factors integrons-integrase responsible for its dissemination. It may also assist in global surveillance of antibiotic resistance and policies to curtail unnecessary antibiotic use.202133181985
5254180.9998Dissemination of the tet(X)-Variant Genes from Layer Farms to Manure-Receiving Soil and Corresponding Lettuce. The occurrence of high-level tigecycline resistance tet(X) variant genes represents a new transferable resistance crisis to food safety and human health. Here, we investigated the abundance of tet(X)-variant genes [tet(X), tet(X1) to tet(X6)] in 33 samples collected from layer manures, manured/un-manured soils, and corresponding lettuce from three provinces in China. The results showed the occurrence of tet(X)/(X2), tet(X3), and tet(X4) in 24 samples. The detection rate of tet(X)/(X2) (23/24) is higher than that of tet(X3) (7/24) and tet(X4) (2/24), and tet(X)/tet(X2) and tet(X3) were found to be enriched and more abundant in most manured soil and several lettuce samples from manured soils than that from manure samples. Twenty six tigecycline-resistant bacteria were isolated, and tet(X)-variant genes were found to be disseminated not only by bacterial clone spreading but also via multidrug resistance plasmids. The total concentrations of tet(X)-variant genes showed significantly positive correlations (R = 0.683, p < 0.001) with ISCR2. Two veterinary tetracyclines (tetracycline and oxytetracycline) and other classes of antimicrobials (enrofloxacin, azithromycin, thiamphenicol, and florfenicol) showed significant correlations with the total concentrations of tet(X)-variant genes (R = 0.35-0.516, p < 0.05). The findings indicate the transmission of tet(X)-variant genes from layer manures to their receiving environmental soils and lettuce and highlight the contribution of veterinary antimicrobials to the spread of tet(X)-variant genes.202133427447
2895190.9998Diversity of antimicrobial resistance genes and class-1-integrons in phylogenetically related porcine and human Escherichia coli. Antimicrobial resistant bacteria and resistance genes can be transferred between the microbial flora of humans and animals. To assess the dimension of this risk, we compared the phylogenetic ancestry of human and porcine tetracycline-insusceptible Escherichia coli. Further, we compared the resistance gene profiles (tetA/tetB/tetC/tetD/tetM/sulI/sulII/sulIII/strA-strB/addA) and the prevalence of class-1-integrons in isolates of identical and different phylogroups by endpoint-PCR. This is the first genotypic comparison of antimicrobial resistance in E. coli from humans and animals which allows for the phylogenetic ancestry of the isolates. E. coli isolates from diseased humans belonged regularly to phylogroup B2 (24.3%) or D (30.9%) and were rarely not typeable (7.2%); by contrast, isolates from pig manure were regularly not typeable (46.7%) and rarely grouped into phylogroup B2 (2.2%) or D (2.9%). Class-1-integrons were detected in 40.8% of clinical (n=152), in 9.5% of community-derived (n=21) and in 10.9% of porcine (n=137) E. coli. The prevalence of sulI (42.4%/16.0%) in phylogroup A and of tetA, tetB and sulII in phylogroup B1 differed significantly between human clinical and porcine strains. Human clinical isolates (except B2-isolates) carried significantly more different resistance genes per strain, compared to porcine or community-derived isolates. ERIC-PCR-analysis of B2- (and D-) isolates with identical genetic profiles revealed that only a minor part was clonally related. The dominant resistance gene profiles differed depending on phylogroup and source. Human and porcine isolates do not exceedingly share their genes, and might rapidly adapt their resistance gene equipment to meet the requirements of a new environment. The study underlines that resistance gene transfer between human and porcine isolates is limited, even in phylogenetically related isolates.201222854332