Mobile Genomic Island GEI-FN1A in Aeromonas salmonicida FN1 Contributes to the Spread of Antibiotic-Resistance Genes. - Related Documents




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303001.0000Mobile Genomic Island GEI-FN1A in Aeromonas salmonicida FN1 Contributes to the Spread of Antibiotic-Resistance Genes. Antibiotics are used to treat severe bacterial infections. However, owing to excessive antibiotic use, bacteria under high selective pressure for antibiotics develop resistance through spontaneous mutation or by acquiring antibiotic-resistance genes (ARGs) through horizontal gene transfer (HGT). Horizontal transfer of ARGs among bacteria in the environment can lead to the emergence of multidrug-resistant (MDR) bacteria that infect animals and humans, thus causing disease outbreaks. In this study, MDR strain FN1 was isolated from a feces-contaminated soil sample from a chicken farm under pressure from the antibiotic florfenicol (16 mg/L) and identified as Aeromonas salmonicida. Whole-genome sequencing and analysis revealed the 86.8-kb antibiotic-resistant genomic island, GEI-FN1A, in the FN1 genome. Genome annotation revealed that GEI-FN1A carried several ARGs, including two tetracycline-resistance genes [tetR and tet(A)], three aminoglycoside-resistance genes [aph(6), aph(3"), and aac(3)], one trimethoprim-resistance gene (dfrB4), two chloramphenicol/florfenicol-resistance genes (catB3 and floR), three macrolide-resistance genes [mphR(A), mrx(A), and mph(A)] and two sul1 genes. GEI-FN1A also contained genes encoding integrase, transposase, and recombinase, which mediate the horizontal transfer of MDR genes. These findings suggest that GEI-FN1A in A. salmonicida FN1 can potentially spread ARGs among environmental bacteria.202540553200
344210.9991Florfenicol and oxazolidone resistance status in livestock farms revealed by short- and long-read metagenomic sequencing. Antibiotic resistance genes (ARGs) as a novel type of environmental pollutant pose a health risk to humans. Oxazolidinones are one of the most important antibiotics for the treatment of Gram-positive bacterial infections in humans. Although oxazolidinones are not utilized in the livestock industry, florfenicol is commonly used on farms to treat bacterial infections, which may contribute to the spread of the cfr, optrA, and poxtA genes on farms. Using metagenomics sequencing, we looked into the antibiotic resistome context of florfenicol and oxazolidinone in 10 large-scale commercial farms in China. We identified 490 different resistance genes and 1,515 bacterial genera in the fecal samples obtained from 10 farms. Florfenicol-resistant Kurthia, Escherichia, and Proteus were widely present in these samples. The situation of florfenicol and oxazolidone resistance in pig farms is even more severe. The total number of genes and the abundance of drug resistance genes were higher in pigs than in chickens, including optrA and poxtA. All the samples we collected had a high abundance of fexA and floR. Through nanopore metagenomic analysis of the genetic environment, we found that plasmids, integrative and conjugative element (ICE), and transposons (Tn7-like and Tn558) may play an important role in the spread of floR, cfr, and optrA. Our findings suggest that florfenicol and oxazolidinone resistance genes have diverse genetic environments and are at risk of co-transmission with, for example, tetracycline and aminoglycoside resistance genes. The spread of florfenicol- and oxazolidinone-resistant bacteria on animal farms should be continuously monitored.202236338088
344320.9991A hybrid DNA sequencing approach is needed to properly link genotype to phenotype in multi-drug resistant bacteria. Antibiotic resistance genes (ARGs) are now viewed as emerging contaminants posing a potential worldwide human health risk. The degree to which ARGs are transferred to other bacteria via mobile genetic elements (MGEs), including insertion sequences (ISs), plasmids, and phages, has a strong association with their likelihood to function as resistance transfer determinants. Consequently, understanding the structure and function of MGEs is paramount to assessing future health risks associated with ARGs in an environment subjected to strong antibiotic pressure. In this study we used whole genome sequencing, done using MinION and HiSeq platforms, to examine antibiotic resistance determinants among four multidrug resistant bacteria isolated from fish farm effluent in Jeju, South Korea. The combined data was used to ascertain the association between ARGs and MGEs. Hybrid assembly using HiSeq and MinION reads revealed the presence of IncFIB(K) and pVPH2 plasmids, whose sizes were verified using pulsed field gel electrophoresis. Twenty four ARGs and 95 MGEs were identified among the 955 coding sequences annotated on these plasmids. More importantly, 22 of 24 ARGs conferring resistance to various antibiotics were found to be located near MGEs, whereas about a half of the ARGs (11 out of 21) were so in chromosomes. Our results also suggest that the total phenotypic resistance exhibited by the isolates was mainly contributed by these putatively mobilizable ARGs. The study gives genomic insights into the origins of putatively mobilizable ARGs in bacteria subjected to selection pressure.202134330011
176330.9991Multidrug Resistance Genes Carried by a Novel Transposon Tn7376 and a Genomic Island Named MMGI-4 in a Pathogenic Morganella morganii Isolate. Antimicrobial resistance in Morganella morganii is increasing in recent years, which is mainly introduced via extra genetic and mobile elements. The aim of our study is to analyze the multidrug resistance (MDR) and characterize the mobile genetic elements (MGEs) in M. morganii isolates. Here, we report the characteristic of a pathogenic M. morganii isolate containing multidrug resistance genes that are mainly carried by a novel transposon Tn7376 and a genomic island. Sequence analysis suggested that the Tn7376 could be generated through homologous recombination between two different IS26-bounded translocatable units (TUs), namely, module A (IS26-Hp-IS26-mph(A)-mrx(A)-mphR-IS6100-chrA-sul1-qacEΔ1) and module B (ISCR1-sul1-qacEΔ1-cmlA1-aadA1-aadB-intI1-IS26), and the genomic island named MMGI-4 might derive from a partial structure of different original genomic islands that also carried IS26-mediated TUs. Notably, a 2,518-bp sequence linked to the module A and B contains a 570-bp dfrA24 gene. To the best of our knowledge, this is the first report of the novel Tn7376 possessing a complex class 1 integron that carried an infrequent gene dfrA24 in M. morganii. IMPORTANCE Mobile genetic elements (MGEs), especially for IS26-bounded translocatable units, may act as a reservoir for a variety of antimicrobial resistance genes in clinically important pathogenic bacteria. We expounded this significant genetic characteristic by investigating a representative M. morganii isolate containing multidrug resistance genes, including the infrequent dfrA24. Our study suggested that these acquired resistance genes were mainly driven by IS26-flanked important MGEs, such as the novel Tn7376 and the MMGI-4. We demonstrated that IS26-related MGEs contributed to the emergence of the extra gene dfrA24 in M. morganii through some potential genetic events like recombination, transposition, and integration. Therefore, it is of importance to investigate persistently the prevalence these MEGs in the clinical pathogens to provide risk assessment of emergence and development of novel resistance genes.202235510850
453240.9990Acquired genetic mechanisms of a multiresistant bacterium isolated from a treatment plant receiving wastewater from antibiotic production. The external environment, particularly wastewater treatment plants (WWTPs), where environmental bacteria meet human commensals and pathogens in large numbers, has been highlighted as a potential breeding ground for antibiotic resistance. We have isolated the extensively drug-resistant Ochrobactrum intermedium CCUG 57381 from an Indian WWTP receiving industrial wastewater from pharmaceutical production contaminated with high levels of quinolones. Antibiotic susceptibility testing against 47 antibiotics showed that the strain was 4 to >500 times more resistant to sulfonamides, quinolones, tetracyclines, macrolides, and the aminoglycoside streptomycin than the type strain O. intermedium LMG 3301T. Whole-genome sequencing identified mutations in the Indian strain causing amino acid substitutions in the target enzymes of quinolones. We also characterized three acquired regions containing resistance genes to sulfonamides (sul1), tetracyclines [tet(G) and tetR], and chloramphenicol/florfenicol (floR). Furthermore, the Indian strain harbored acquired mechanisms for horizontal gene transfer, including a type I mating pair-forming system (MPFI), a MOBP relaxase, and insertion sequence transposons. Our results highlight that WWTPs serving antibiotic manufacturing may provide nearly ideal conditions for the recruitment of resistance genes into human commensal and pathogenic bacteria.201324038701
451850.9990Resistome, Mobilome and Virulome Analysis of Shewanella algae and Vibrio spp. Strains Isolated in Italian Aquaculture Centers. Antimicrobial resistance is a major public health concern restricted not only to healthcare settings but also to veterinary and environmental ones. In this study, we analyzed, by whole genome sequencing (WGS) the resistome, mobilome and virulome of 12 multidrug-resistant (MDR) marine strains belonging to Shewanellaceae and Vibrionaceae families collected at aquaculture centers in Italy. The results evidenced the presence of several resistance mechanisms including enzyme and efflux pump systems conferring resistance to beta-lactams, quinolones, tetracyclines, macrolides, polymyxins, chloramphenicol, fosfomycin, erythromycin, detergents and heavy metals. Mobilome analysis did not find circular elements but class I integrons, integrative and conjugative element (ICE) associated modules, prophages and different insertion sequence (IS) family transposases. These mobile genetic elements (MGEs) are usually present in other aquatic bacteria but also in Enterobacteriaceae suggesting their transferability among autochthonous and allochthonous bacteria of the resilient microbiota. Regarding the presence of virulence factors, hemolytic activity was detected both in the Shewanella algae and in Vibrio spp. strains. To conclude, these data indicate the role as a reservoir of resistance and virulence genes in the environment of the aquatic microbiota present in the examined Italian fish farms that potentially might be transferred to bacteria of medical interest.202032326629
453160.9990Various pAQU plasmids possibly contribute to disseminate tetracycline resistance gene tet(M) among marine bacterial community. Emergence of antibiotic-resistant bacteria in the aquaculture environment is a significant problem for disease control of cultured fish as well as in human public health. Conjugative mobile genetic elements (MGEs) are involved in dissemination of antibiotic resistance genes (ARGs) among marine bacteria. In the present study, we first designed a PCR targeting traI gene encoding essential relaxase for conjugation. By this new PCR, we demonstrated that five of 83 strains isolated from a coastal aquaculture site had traI-positive MGEs. While one of the five strains that belonged to Shewanella sp. was shown to have an integrative conjugative element of the SXT/R391 family (ICEVchMex-like), the MGEs of the other four strains of Vibrio spp. were shown to have the backbone structure similar to that of previously described in pAQU1. The backbone structure shared by the pAQU1-like plasmids in the four strains corresponded to a ~100-kbp highly conserved region required for replication, partition and conjugative transfer, suggesting that these plasmids constituted "pAQU group." The pAQU group plasmids were shown to be capable of conjugative transfer of tet(M) and other ARGs from the Vibrio strains to E. coli. The pAQU group plasmid in one of the examined strains was designated as pAQU2, and its complete nucleotide sequence was determined and compared with that of pAQU1. The results revealed that pAQU2 contained fewer ARGs than pAQU1 did, and most of the ARGs in both of these plasmids were located in the similar region where multiple transposases were found, suggesting that the ARGs were introduced by several events of DNA transposition into an ancestral plasmid followed by drug selection in the aquaculture site. The results of the present study indicate that the "pAQU group" plasmids may play an important role in dissemination of ARGs in the marine environment.201424860553
177870.9990Four novel resistance integron gene-cassette occurrences in bacterial isolates from zhenjiang, china. Integrons, which are widely distributed among bacteria and are strongly associated with resistance, are specialized genetic elements that are capable of capturing, integrating, and mobilizing gene cassette. In this work, we investigated classes 1, 2, and 3 integrons associated integrases genes in 365 bacteria isolates, amplified and analyzed the structure of class 1 integron, detected 8 resistant gene cassettes [dfr17, aadA5, aadA1, aadA2, dhfrI, aadB, aac(6')-II, and pse-I], and found four novel gene-cassette arrays. We also found that commensal bacteria in the common microenvironment had the same integron gene cassette, which provided direct evidence that integron was an important horizontal transmission element.200919365688
996280.9990Metadata Analysis of mcr-1-Bearing Plasmids Inspired by the Sequencing Evidence for Horizontal Transfer of Antibiotic Resistance Genes Between Polluted River and Wild Birds. We sequenced the whole genomes of three mcr-1-positive multidrug-resistant E. coli strains, which were previously isolated from the environment of egret habitat (polluted river) and egret feces. The results exhibit high correlation between antibiotic-resistant phenotype and genotype among the three strains. Most of the mobilized antibiotic resistance genes (ARGs) are distributed on plasmids in the forms of transposons or integrons. Multidrug-resistant (MDR) regions of high homology are detected on plasmids of different E. coli isolates. Therefore, horizontal transfer of resistance genes has facilitated the transmission of antibiotic resistance between the environmental and avian bacteria, and the transfer of ARGs have involved multiple embedded genetic levels (transposons, integrons, plasmids, and bacterial lineages). Inspired by this, systematic metadata analysis was performed for the available sequences of mcr-1-bearing plasmids. Among these plasmids, IncHI2 plasmids carry the most additional ARGs. The composition of these additional ARGs varies according to their geographical distribution. The phylogenetic reconstruction of IncI2 and IncX4 plasmids provides the evidence for their multiregional evolution. Phylogenetic analysis at the level of mobile genetic element (plasmid) provides important epidemiological information for the global dissemination of mcr-1 gene. Highly homologous mcr-1-bearing IncI2 plasmids have been isolated from different regions along the East Asian-Australasian Flyway, suggesting that migratory birds may mediate the intercontinental transportation of ARGs.202032210943
497390.9990Plasmidome analysis of a hospital effluent biofilm: Status of antibiotic resistance. Plasmids are widely involved in the dissemination of characteristics within bacterial communities. Their genomic content can be assessed by high-throughput sequencing of the whole plasmid fraction of an environment, the plasmidome. In this study, we analyzed the plasmidome of a biofilm formed in the effluents of the teaching hospital of Clermont-Ferrand (France). Our analysis discovered >350 new complete plasmids, with a length ranging from 1219 to 40,193 bp. Forty-two plasmid incompatibility (Inc) groups were found among all the plasmid contigs. Ten large plasmids, described here in detail, were reconstructed from plasmid contigs, seven of which carried antibiotic resistance genes. Four plasmids potentially confer resistance to numerous families of antibiotics, including carbapenems, aminoglycosides, colistin, and chloramphenicol. Most of these plasmids were affiliated to Proteobacteria, a phylum of Gram-negative bacteria. This study therefore illustrates the composition of an environmental mixed biofilm in terms of plasmids and antibiotic resistance genes.202235691511
1775100.9990The IncC and IncX1 resistance plasmids present in multi-drug resistant Escherichia coli strains isolated from poultry manure in Poland. The study describes the whole-genome sequencing of two antibiotic-resistant representative Escherichia coli strains, isolated from poultry manure in 2020. The samples were obtained from a commercial chicken meat production facility in Poland. The antibiotic resistance profile was characterized by co-resistance to β-lactam antibiotics, aminoglycosides, and fluoroquinolones. The three identified resistance plasmids (R-plasmids), pECmdr13.2, pECmdr13.3, and pECmdr14.1, harbored various genes conferring resistance to tetracyclines (tetR[A]) for, aminoglycoside (aph, aac, and aad families), β-lactam (bla(CMY-2), bla(TEM-176)), sulfonamide (sul1, sul2), fluoroquinolone (qnrS1), and phenicol (floR). These plasmids, which have not been previously reported in Poland, were found to carry IS26 insertion elements, the intI1-integrase gene, and conjugal transfer genes, facilitating horizontal gene transfer. Plasmids pECmdr13.2 and pECmdr14.1 also possessed a mercury resistance gene operon related to transposon Tn6196; this promotes plasmid persistence even without antibiotic selection pressure due to co-selection mechanisms such as co-resistance. The chicken manure-derived plasmids belonged to the IncX1 (narrow host range) and IncC (broad host range) incompatibility groups. Similar plasmids have been identified in various environments, clinical isolates, and farm animals, including cattle, swine, and poultry. This study holds significant importance for the One Health approach, as it highlights the potential for antibiotic-resistant bacteria from livestock and food sources, particularly E. coli, to transfer through the food chain to humans and vice versa.202439007976
4517110.9990Integrative and Conjugative Elements-Positive Vibrio parahaemolyticus Isolated From Aquaculture Shrimp in Jiangsu, China. The development of multidrug- and toxin-resistant bacteria as a result of increasing industrialization and sustained and intense antimicrobial use in aquaculture results in human health problems through increased incidence of food-borne illnesses. Integrative and conjugative elements (ICEs) are self-transmissible mobile genetic elements that allow bacteria to acquire complex new traits through horizontal gene transfer and encode a wide variety of genetic information, including resistance to antibiotics and heavy metals; however, there is a lack of studies of ICEs of environmental origin in Asia. Here, we determined the prevalence, genotypes, heavy metal resistance and antimicrobial susceptibility of 997 presumptive strains of Vibrio parahaemolyticus (tlh (+), tdh (-)), a Gram-negative bacterium that causes gastrointestinal illness in humans, isolated from four species of aquaculture shrimp in Jiangsu, China. We found that 59 of the 997 isolates (5.9%) were ICE-positive, and of these, 9 isolates tested positive for all resistance genes. BLAST analysis showed that similarity for the eight strains to V. parahaemolyticus was 99%. Tracing the V. parahaemolyticus genotypes, showed no significant relevance of genotype among the antimicrobial resistance strains bearing the ICEs or not. Thus, in aquaculture, ICEs are not the major transmission mediators of resistance to antibiotics or heavy metals. We suggest future research to elucidate mechanisms that drive transmission of resistance determinants in V. parahaemolyticus.201931379767
3031120.9989Novel Mobilizable Genomic Island GEI-D18A Mediates Conjugational Transfer of Antibiotic Resistance Genes in the Multidrug-Resistant Strain Rheinheimera sp. D18. Aquatic environments act as reservoirs of antimicrobial-resistant bacteria and antimicrobial resistance (AMR) genes, and the dissemination of antibiotic resistance from these environments is of increasing concern. In this study, a multidrug-resistant bacterial strain, identified as Rheinheimera sp. D18, was isolated from the sea water of an industrial maricultural system in the Yellow Sea, China. Whole-genome sequencing of D18 revealed the presence of a novel 25.8 kb antibiotic resistance island, designated GEI-D18A, which carries several antibiotic resistance genes (ARGs), including aadA1, aacA3, tetR, tet(B), catA, dfrA37, and three sul1 genes. Besides, integrase, transposase, resolvase, and recombinase encoding genes were also identified in GEI-D18A. The transferability of GEI-D18A was confirmed by mating experiments between Rheinheimera sp. D18 and Escherichia coli 25DN, and efflux pump inhibitor assays also suggested that tet(B) in GEI-D18A was responsible for tetracycline resistance in both D18 and the transconjugant. This study represents the first characterization of a mobilizable antibiotic resistance island in a species of Rheinheimera and provides evidence that Rheinheimera spp. could be important reservoirs and vehicles for ARGs in the Yellow Sea area.202032318052
3353130.9989Plasmid and integron-associated antibiotic resistance in Escherichia coli isolated from domestic wastewater treatment plants. The rapid dissemination of antibiotic resistance genes (ARGs) represents a significant global threat, with wastewater treatment plants (WWTPs) playing an important role as reservoirs and propagation hubs. In this study, we performed whole-genome sequencing and bioinformatic analyses on eight multidrug-resistant Escherichia coli isolates previously obtained from domestic WWTPs in Costa Rica. We identified 61 ARGs (23 unique), with 40 located on plasmids, and 21 on chromosomal sequences, seven of which were within integrons. Several ARGs were associated with resistance to clinically and veterinary important antibiotics, including sulfamethoxazole/trimethoprim, beta-lactams, and tetracyclines. One hundred twenty-one virulence-associated genes (29 unique) were detected, with 16 located on plasmids. Notably, the presence of virulence factors such as ompT and hlyF genes alongside ARGs on plasmids underscores the transmissible pathogenic potential of WWTP-associated E. coli strains. These findings highlight the role of small domestic WWTPs in disseminating pathogenic and multidrug-resistant bacteria and their mobile genetic elements, emphasizing the need for further research to understand how these discharges impact aquatic environments.202540246693
9961140.9989Evolution and comparative genomics of pAQU-like conjugative plasmids in Vibrio species. OBJECTIVES: To investigate a set of MDR conjugative plasmids found in Vibrio species and characterize the underlying evolution process. METHODS: pAQU-type plasmids from Vibrio species were sequenced using both Illumina and PacBio platforms. Bioinformatics tools were utilized to analyse the typical MDR regions and core genes in the plasmids. RESULTS: The nine pAQU-type plasmids ranged from ∼160 to 206 kb in size and were found to harbour as many as 111 core genes encoding conjugative, replication and maintenance functions. Eight plasmids were found to carry a typical MDR region, which contained various accessory and resistance genes, including ISCR1-blaPER-1-bearing complex class 1 integrons, ISCR2-floR, ISCR2-tet(D)-tetR-ISCR2, qnrVC6, a Tn10-like structure and others associated with mobile elements. Comparison between a plasmid without resistance genes and different MDR plasmids showed that integration of different mobile elements, such as IS26, ISCR1, ISCR2, IS10 and IS6100, into the plasmid backbone was the key mechanism by which foreign resistance genes were acquired during the evolution process. CONCLUSIONS: This study identified pAQU-type plasmids as emerging MDR conjugative plasmids among important pathogens from different origins in Asia. These findings suggest that aquatic bacteria constitute a major reservoir of resistance genes, which may be transmissible to other human pathogens during food production and processing.201728637205
1981150.9989Detecting Class 1 Integrons and Their Variable Regions in Escherichia coli Whole-Genome Sequences Reported from Andean Community Countries. Various genetic elements, including integrons, are known to contribute to the development of antimicrobial resistance. Class 1 integrons have been identified in E. coli isolates and are associated with multidrug resistance in countries of the Andean Community. However, detailed information on the gene cassettes located on the variable regions of integrons is lacking. Here, we investigated the presence and diversity of class 1 integrons, using an in silico approach, in 2533 whole-genome sequences obtained from EnteroBase. IntFinder v1.0 revealed that almost one-third of isolates contained these platforms. Integron-bearing isolates were associated with environmental, food, human, and animal origins reported from all countries under scrutiny. Moreover, they were identified in clones known for their pathogenicity or multidrug resistance. Integrons carried cassettes associated with aminoglycoside (aadA), trimethoprim (dfrA), cephalosporin (blaOXA; blaDHA), and fluoroquinolone (aac(6')-Ib-cr; qnrB) resistance. These platforms showed higher diversity and larger numbers than previously reported. Moreover, integrons carrying more than three cassettes in their variable regions were determined. Monitoring the prevalence and diversity of genetic elements is necessary for recognizing emergent patterns of resistance in pathogenic bacteria, especially in countries where various factors are recognized to favor the selection of resistant microorganisms.202438786123
3446160.9989Prevalence and transmission risk of colistin and multidrug resistance in long-distance coastal aquaculture. Due to the wide use of antibiotics, intensive aquaculture farms have been recognized as a significant reservoir of antibiotic resistomes. Although the prevalence of colistin resistance genes and multidrug-resistant bacteria (MDRB) has been documented, empirical evidence for the transmission of colistin and multidrug resistance between bacterial communities in aquaculture farms through horizontal gene transfer (HGT) is lacking. Here, we report the prevalence and transmission risk of colistin and multidrug resistance in 27 aquaculture water samples from 9 aquaculture zones from over 5000 km of subtropical coastlines in southern China. The colistin resistance gene mcr-1, mobile genetic element (MGE) intl1 and 13 typical antibiotic resistance genes (ARGs) were prevalent in all the aquaculture water samples. Most types of antibiotic (especially colistin) resistance are transmissible in bacterial communities based on evidence from laboratory conjugation and transformation experiments. Diverse MDRB were detected in most of the aquaculture water samples, and a strain with high-level colistin resistance, named Ralstonia pickettii MCR, was isolated. The risk of horizontal transfer of the colistin resistance of R. pickettii MCR through conjugation and transformation was low, but the colistin resistance could be steadily transmitted to offspring through vertical transfer. The findings have important implications for the future regulation of antibiotic use in aquaculture farms globally to address the growing threat posed by antibiotic resistance to human health.202337935916
3447170.9989The Impact of Urban Pollution on Plasmid-Mediated Resistance Acquisition in Enterobacteria from a Tropical River. Background: The exposure of environmental bacteria to contaminants in aquatic ecosystems accelerates the dissemination of antibiotic-resistance genes (ARGs) through horizontal gene transfer (HGT). Methods: In this study, we sampled three locations along a contamination gradient of a polluted river, focusing on isolating Enterobacteria from the surface waters to investigate the relationship between urban pollution and antibiotic resistance. The genomes of 15 isolates (5 per site) were sequenced to identify plasmid-borne ARGs and their association with resistance phenotypes. Results: Isolates from the site with the highest contamination (Site 3) showeda larger number of ARGs, plasmids, and resistance phenotypes. Notably, one of the isolates analyzed, E. coli A231-12, exhibited phenotypic resistance to seven antibiotics, presumably conferred by a single plasmid carrying 12 ARGs. Comparative analysis of this plasmid revealed its close evolutionary relationship with another IncH plasmid hosted by Salmonella enterica, underscoring its high ARG burden in the aquatic environment. Other plasmids identified in our isolates carried sul and dfrA genes, conferring resistance to trimethoprim/sulfamethoxazole, a commonly prescribed antibiotic combination in clinical settings. Conclusions: These results highlight the critical need to expand research on the link between pollution and plasmid-mediated antimicrobial resistance in aquatic ecosystems, which can act as reservoirs of ARGs.202439596782
3263180.9989Short- and long-read metagenomics insight into the genetic contexts and hosts of mobile antibiotic resistome in Chinese swine farms. Antibiotic resistance genes (ARGs) are emerging environmental contaminants posing a threat to public health. Intensive swine farms are recognized as hotspots for antibiotic resistance genes (ARGs). However, antibiotic resistome and their genetic contexts, hosts, and transferability in Chinese swine farms remain largely unexplored. Here, we used Illumina and Oxford Nanopore metagenomics sequencing to investigate the antibiotic resistome context of 14 distantly located large-scale (10,000 animals per year) commercial swine farms in China. We identified high abundant and diverse ARGs (609,966.8 with 1433 types, belonging to 38 different antibiotic classes) in all samples, including those encoding resistance to clinically critical important antibiotics (such as mcr, tetX, optrA, poxtA, qnr and bla(CTX-M)). About 75% of the ARGs detected were carried by mobile genetic elements (mainly plasmids), suggesting their high transmission potential into receiving environments. Host-tracking analysis identified Clostridiales, Faecalibacterium prausnitzii and Escherichia coli as the predominant bacterial hosts of mobile ARGs. Notably, genome binning generated 246 high-completeness draft genomes. Genetic context analysis of the multiple resistant (MDR) genes in binned genomes showed the involvement of insertion sequences (ISs), integron and SGI2 genomic island, implying their importance role in promoting the development of MDR bacteria. Overall, these findings substantially expand our current knowledge of mobile antibiotic resistome in Chinese swine farms, and suggest reasonable management of animal wastes in swine farms to reduce the dissemination of antibiotic resistance to the environment.202235259381
4974190.9989Genomic Plasticity of Multidrug-Resistant NDM-1 Positive Clinical Isolate of Providencia rettgeri. We performed a detailed whole-genome sequence analysis of Providencia rettgeri H1736, a multidrug-resistant clinical pathogen isolated in Israel in 2011. The objective was to describe the genomic flexibility of this bacterium that has greatly contributed to its pathogenicity. The genome has a chromosome size of 4,609,352 bp with 40.22% GC content. Five plasmids were predicted, as well as other mobile genetic elements (MGEs) including phages, genomic islands, and integrative and conjugative elements. The resistome consisted of a total of 27 different antibiotic resistance genes including blaNDM-1, mostly located on MGEs. Phenotypically, the bacteria displayed resistance to a total of ten different antimicrobial classes. Various features such as metabolic operons (including a novel carbapenem biosynthesis operon) and virulence genes were also borne on the MGEs, making P. rettgeri H1736 significantly different from other P. rettgeri isolates. A large quantity of the genetic diversity that exists in P. rettgeri H1736 was due to extensive horizontal gene transfer events, leading to an enormous presence of MGEs in its genome. Most of these changes contributed toward the pathogenic evolution of this bacterium.201627386606