# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 9254 | 0 | 0.9933 | Horizontal gene transfer in human pathogens. Horizontal gene transfer has a tremendous impact on the genome plasticity, adaptation and evolution of bacteria. Horizontally transferred mobile genetic elements are involved in the dissemination of antibiotic resistance and virulence genes, thus contributing to the emergence of novel "superbugs". This review provides update on various mechanisms of horizontal gene transfer and examines how horizontal gene transfer contributes to the evolution of pathogenic bacteria. Special focus is paid to the role horizontal gene transfer plays in pathogenicity of the emerging human pathogens: hypervirulent Clostridium difficile and Escherichia coli (including the most recent haemolytic uraemic syndrome outbreak strain) and methicillin-resistant Staphylococcus aureus (MRSA), which have been associated with largest outbreaks of infection recently. | 2015 | 23862575 |
| 9946 | 1 | 0.9931 | Genomic insights into plasmid-mediated antimicrobial resistance in the bacterium Bhargavaea beijingensis strain PS04. The dissemination of antimicrobial-resistant bacteria through environment is a major health concern for public health. Pathogenic bacteria in natural environment can mediate the transfer of antimicrobial-resistant genes via horizontal gene transfer to naturally occurring bacteria in the soil. Bhargavaea beijingensis is a Gram-negative bacterium that is commonly found in soil and water. In recent years, there has been an emergence of antibiotic-resistant strains of environmental bacteria, which pose a significant threat to human health. One mechanism of antibiotic resistance in bacteria is through the acquisition of plasmids, which can carry genes that confer resistance to various antibiotics. In this study, a novel plasmid of repUS12 replicon type was identified in the strain PS04 of B. beijingensis, which carried the ermT and tet(L) genes, encoding resistance to macrolides, lincosamides, and tetracycline. The plasmid was found to be the first of its kind in B. beijingensis and was thought to have been acquired through horizontal gene transfer. The emergence of plasmid-mediated resistance in B. beijingensis highlights the need for continued surveillance and monitoring of antibiotic resistance in environmental bacteria. | 2023 | 38133813 |
| 9836 | 2 | 0.9930 | Staphylococcus aureus mobile genetic elements. Among the bacteria groups, most of them are known to be beneficial to human being whereas only a minority is being recognized as harmful. The pathogenicity of bacteria is due, in part, to their rapid adaptation in the presence of selective pressures exerted by the human host. In addition, through their genomes, bacteria are subject to mutations, various rearrangements or horizontal gene transfer among and/or within bacterial species. Bacteria's essential metabolic functions are generally encoding by the core genes. Apart of the core genes, there are several number of mobile genetic elements (MGE) acquired by horizontal gene transfer that might be beneficial under certain environmental conditions. These MGE namely bacteriophages, transposons, plasmids, and pathogenicity islands represent about 15% Staphylococcus aureus genomes. The acquisition of most of the MGE is made by horizontal genomic islands (GEI), recognized as discrete DNA segments between closely related strains, transfer. The GEI contributes to the wide spread of microorganisms with an important effect on their genome plasticity and evolution. The GEI are also involve in the antibiotics resistance and virulence genes dissemination. In this review, we summarize the mobile genetic elements of S. aureus. | 2014 | 24728610 |
| 4366 | 3 | 0.9930 | Mercury bioremediation by mercury resistance transposon-mediated in situ molecular breeding. Mercury-resistant (Hg(R)) bacteria occur in various bacterial species from a wide variety of environmental sources. Resistance is conferred by a set of operon genes termed the mer operon. Many Hg(R) bacteria have been isolated from diverse environments and clinical samples, and it is recognized that mer operons are often localized on transposons. Previous research reports have suggested that Hg(R) transposons participate in the horizontal gene transfer of mer operons among bacteria. This was confirmed by a study that found that mer operons were distributed worldwide in Bacilli with dissemination of TnMERI1-like transposons. In this mini review, possible strategies for transposon-mediated in situ molecular breeding (ISMoB) of Hg(R) bacteria in their natural habitat are discussed. In ISMoB, the target microorganisms for breeding are indigenous bacteria that are not Hg(R) but that are dominant and robust in their respective environments. Additionally, we propose a new concept of bioremediation technology for environmental mercury pollution by applying transposon-mediated ISMoB for environmental mercury pollution control. | 2018 | 29479648 |
| 9253 | 4 | 0.9930 | Horizontally transferred genetic elements and their role in pathogenesis of bacterial disease. This article reviews the roles that laterally transferred genes (LTG) play in the virulence of bacterial pathogens. The features of LTG that allow them to be recognized in bacterial genomes are described, and the mechanisms by which LTG are transferred between and within bacteria are reviewed. Genes on plasmids, integrative and conjugative elements, prophages, and pathogenicity islands are highlighted. Virulence genes that are frequently laterally transferred include genes for bacterial adherence to host cells, type 3 secretion systems, toxins, iron acquisition, and antimicrobial resistance. The specific roles of LTG in pathogenesis are illustrated by specific reference to Escherichia coli, Salmonella, pyogenic streptococci, and Clostridium perfringens. | 2014 | 24318976 |
| 9839 | 5 | 0.9929 | The coexistence of monopartite integrative and conjugative elements in the genomes of Acidobacteria. Soil bacteria can rapidly adapt to environmental perturbations through horizontal gene transfer. Acidobacteria is one of the most persistent dominant phyla in the soil. However, the role of these organisms in terrestrial ecosystems remains elusive. Here we identified and describe the integrative and conjugative elements (ICEs) in the published complete genomes of Acidobacteria. In total, ten novel ICEs were identified, in which nine were found integrated as three separated monopartite ICEs in the single chromosome sequences of three Acidobacteria. These ICEs carry a repertoire of genes with potential environmental roles, including heavy metal resistance, iron uptake, secondary metabolism, and antibiotic resistance. To our knowledge, these are the first evidence of three monopartite ICEs identified in the single chromosome, and this might be due to the absence of recognizable entry exclusion systems. We hypothesis that the coexistence of multiples ICEs in the chromosome of Acidobacteria might reflect a major advantage for the survival, resistance, and persistence of phylum in the environment. | 2021 | 33549716 |
| 9711 | 6 | 0.9929 | Horizontal DNA transfer between bacteria in the environment. In the environment horizontal DNA transfer between various bacterial species and genera takes place by transformation, transduction, but mainly by conjugation. Conjugation is responsible for the spread of genes coding for antibiotic resistance and xenobiotic degradation. Transfer events are reported in animal, rhizosphere and phylloplane ecosystems and in non polluted and polluted water and soil. Genetic exchange between Bacteria and Archaea is also observed. Evaluation of the extent of interspecies gene transfer is crucial in view of the deliberate release of a variety of unmodified and genetically modified microorganisms into the natural environments. | 2003 | 14743976 |
| 4014 | 7 | 0.9929 | Dissemination of Antimicrobial Resistance in Microbial Ecosystems through Horizontal Gene Transfer. The emergence and spread of antibiotic resistance among pathogenic bacteria has been a rising problem for public health in recent decades. It is becoming increasingly recognized that not only antibiotic resistance genes (ARGs) encountered in clinical pathogens are of relevance, but rather, all pathogenic, commensal as well as environmental bacteria-and also mobile genetic elements and bacteriophages-form a reservoir of ARGs (the resistome) from which pathogenic bacteria can acquire resistance via horizontal gene transfer (HGT). HGT has caused antibiotic resistance to spread from commensal and environmental species to pathogenic ones, as has been shown for some clinically important ARGs. Of the three canonical mechanisms of HGT, conjugation is thought to have the greatest influence on the dissemination of ARGs. While transformation and transduction are deemed less important, recent discoveries suggest their role may be larger than previously thought. Understanding the extent of the resistome and how its mobilization to pathogenic bacteria takes place is essential for efforts to control the dissemination of these genes. Here, we will discuss the concept of the resistome, provide examples of HGT of clinically relevant ARGs and present an overview of the current knowledge of the contributions the various HGT mechanisms make to the spread of antibiotic resistance. | 2016 | 26925045 |
| 4037 | 8 | 0.9928 | Heavy metal resistance in bacteria from animals. Resistance to metals and antimicrobials is a natural phenomenon that existed long before humans started to use these products for veterinary and human medicine. Bacteria carry diverse metal resistance genes, often harboured alongside antimicrobial resistance genes on plasmids or other mobile genetic elements. In this review we summarize the current knowledge about metal resistance genes in bacteria and we discuss their current use in the animal husbandry. | 2019 | 30502728 |
| 4172 | 9 | 0.9928 | Variation on a theme; an overview of the Tn916/Tn1545 family of mobile genetic elements in the oral and nasopharyngeal streptococci. The oral and nasopharyngeal streptococci are a major part of the normal microbiota in humans. Most human associated streptococci are considered commensals, however, a small number of them are pathogenic, causing a wide range of diseases including oral infections such as dental caries and periodontitis and diseases at other body sites including sinusitis and endocarditis, and in the case of Streptococcus pneumoniae, meningitis. Both phenotypic and sequence based studies have shown that the human associated streptococci from the mouth and nasopharynx harbor a large number of antibiotic resistance genes and these are often located on mobile genetic elements (MGEs) known as conjugative transposons or integrative and conjugative elements of the Tn916/Tn1545 family. These MGEs are responsible for the spread of the resistance genes between streptococci and also between streptococci and other bacteria. In this review we describe the resistances conferred by, and the genetic variations between the many different Tn916-like elements found in recent studies of oral and nasopharyngeal streptococci and show that Tn916-like elements are important mediators of antibiotic resistance genes within this genus. We will also discuss the role of the oral environment and how this is conducive to the transfer of these elements and discuss the contribution of both transformation and conjugation on the transfer and evolution of these elements in different streptococci. | 2014 | 25368607 |
| 9710 | 10 | 0.9928 | Horizontal gene transfer as a biosafety issue: a natural phenomenon of public concern. The transfer of genetic information between distantly or even unrelated organisms during evolution had been inferred from nucleotide sequence comparisons. These studies provided circumstantial evidence that in rare cases genes had been laterally transmitted amongst organisms of the domains bacteria, archaea and eukarya. Laboratory-based studies confirmed that the gene pools of the various domains of organisms are linked. Amongst the bacterial gene exchange mechanisms transduction, transformation and conjugation, the latter was identified as the mechanism with potentially the broadest host range of transfer. Previously, the issue of horizontal gene transfer has become important in the context of biosafety. Gene transfer studies carried out under more natural conditions such as in model ecosystems or in the environment established that all gene transfer mechanisms worked under these conditions. Moreover, environmental hot-spots were identified where favourable conditions such as nutrient enrichment increased the probability of genetic exchange among bacteria. In particular, the phytosphere was shown to provide conducive conditions for conjugative gene exchange. Concern has been expressed that transfer of recombinant DNA (e.g. antibiotic resistance genes) from genetically modified organisms (GMOs) such as transgenic plants to phytosphere bacteria may occur and thus contribute to the undesirable spread of antibiotic resistance determinants. Studies which were performed to address this issue clearly showed that such a transfer occurs, if at all, at extremely low frequency. | 1998 | 9823660 |
| 9837 | 11 | 0.9927 | Mobilizable genomic islands, different strategies for the dissemination of multidrug resistance and other adaptive traits. Mobile genetic elements are near ubiquitous DNA segments that revealed a surprising variety of strategies for their propagation among prokaryotes and between eukaryotes. In bacteria, conjugative elements were shown to be key drivers of evolution and adaptation by efficiently disseminating genes involved in pathogenicity, symbiosis, metabolic pathways, and antibiotic resistance. Conjugative plasmids of the incompatibility groups A and C (A/C) are important vehicles for the dissemination of antibiotic resistance and the consequent global emergence and spread of multi-resistant pathogenic bacteria. Beyond their own mobility, A/C plasmids were also shown to drive the mobility of unrelated non-autonomous mobilizable genomic islands, which may also confer further advantageous traits. In this commentary, we summarize the current knowledge on different classes of A/C-dependent mobilizable genomic islands and we discuss other DNA hitchhikers and their implication in bacterial evolution. Furthermore, we glimpse at the complex genetic network linking autonomous and non-autonomous mobile genetic elements, and at the associated flow of genetic information between bacteria. | 2017 | 28439449 |
| 4038 | 12 | 0.9927 | Environmental macrolide-lincosamide-streptogramin and tetracycline resistant bacteria. Bacteria can become resistant to antibiotics by mutation, transformation, and/or acquisition of new genes which are normally associated with mobile elements (plasmids, transposons, and integrons). Mobile elements are the main driving force in horizontal gene transfer between strains, species, and genera and are responsible for the rapid spread of particular elements throughout a bacterial community and between ecosystems. Today, antibiotic resistant bacteria are widely distributed throughout the world and have even been isolated from environments that are relatively untouched by human civilization. In this review macrolides, lincosamides, streptogramins, and tetracycline resistance genes and bacteria will be discussed with an emphasis on the resistance genes which are unique to environmental bacteria which are defined for this review as species and genera that are primarily found outside of humans and animals. | 2011 | 21833302 |
| 6518 | 13 | 0.9927 | The role of aquatic ecosystems as reservoirs of antibiotic resistance. Although antibiotic resistance has become a major threat to human health worldwide, this phenomenon has been largely overlooked in studies in environmental settings. Aquatic environments may provide an ideal setting for the acquisition and dissemination of antibiotic resistance, because they are frequently impacted by anthropogenic activities. This review focuses primarily on the emergence and dissemination of antibiotic resistance in the aquatic environment, with a special emphasis on the role of antibiotic resistance genes. | 2014 | 24289955 |
| 4137 | 14 | 0.9927 | The Prehistory of Antibiotic Resistance. Antibiotic resistance is a global problem that is reaching crisis levels. The global collection of resistance genes in clinical and environmental samples is the antibiotic "resistome," and is subject to the selective pressure of human activity. The origin of many modern resistance genes in pathogens is likely environmental bacteria, including antibiotic producing organisms that have existed for millennia. Recent work has uncovered resistance in ancient permafrost, isolated caves, and in human specimens preserved for hundreds of years. Together with bioinformatic analyses on modern-day sequences, these studies predict an ancient origin of resistance that long precedes the use of antibiotics in the clinic. Understanding the history of antibiotic resistance is important in predicting its future evolution. | 2016 | 27252395 |
| 4032 | 15 | 0.9927 | Could bacteriophages transfer antibiotic resistance genes from environmental bacteria to human-body associated bacterial populations? Environments without any contact with anthropogenic antibiotics show a great abundance of antibiotic resistance genes that use to be chromosomal and are part of the core genes of the species that harbor them. Some of these genes are shared with human pathogens where they appear in mobile genetic elements. Diversity of antibiotic resistance genes in non-contaminated environments is much greater than in human and animal pathogens, and in environments contaminated with antibiotic from anthropogenic activities. This suggests the existence of some bottleneck effect for the mobilization of antibiotic resistance genes among different biomes. Bacteriophages have characteristics that make them suitable vectors between different biomes, and as well for transferring genes from biome to biome. Recent metagenomic studies and detection of bacterial genes by genomic techniques in the bacteriophage fraction of different microbiota provide indirect evidences that the mobilization of genes mediated by phages, including antibiotic resistance genes, is far more relevant than previously thought. Our hypothesis is that bacteriophages might be of critical importance for evading one of the bottlenecks, the lack of ecological connectivity that modulates the pass of antibiotic resistance genes from natural environments such as waters and soils, to animal and human microbiomes. This commentary concentrates on the potential importance of bacteriophages in transferring resistance genes from the environment to human and animal body microbiomes, but there is no doubt that transduction occurs also in body microbiomes. | 2013 | 24195016 |
| 4047 | 16 | 0.9927 | Integron involvement in environmental spread of antibiotic resistance. The spread of antibiotic-resistant bacteria is a growing problem and a public health issue. In recent decades, various genetic mechanisms involved in the spread of resistance genes among bacteria have been identified. Integrons - genetic elements that acquire, exchange, and express genes embedded within gene cassettes (GC) - are one of these mechanisms. Integrons are widely distributed, especially in Gram-negative bacteria; they are carried by mobile genetic elements, plasmids, and transposons, which promote their spread within bacterial communities. Initially studied mainly in the clinical setting for their involvement in antibiotic resistance, their role in the environment is now an increasing focus of attention. The aim of this review is to provide an in-depth analysis of recent studies of antibiotic-resistance integrons in the environment, highlighting their potential involvement in antibiotic-resistance outside the clinical context. We will focus particularly on the impact of human activities (agriculture, industries, wastewater treatment, etc.). | 2012 | 22509175 |
| 9732 | 17 | 0.9927 | Interactions of heavy metals with bacteria. The toxicity of heavy metals to bacteria, with particular reference to metal forms and species, has been reviewed. Factors which influence metal forms and thus their potential toxicity, such as pH, chelation and competitive interactions have been discussed. The mechanisms whereby bacteria may influence the forms of heavy metals to which they are exposed have been discussed with reference to the importance of the role of bacteria in immobilisation and environmental cycling of metals. Bacterial resistance to metal toxicity is an environmentally important phenomenon. It may occur from non-specific mechanisms, such as impermeability of the cell, or it may be due to specific resistance transfer factors. The coincidence and co-selection of resistance factors for antibiotics and heavy metals in bacterial populations and the clinical implications of this have been described. | 1980 | 6988964 |
| 9689 | 18 | 0.9927 | Evolution of foodborne pathogens via temperate bacteriophage-mediated gene transfer. Temperate bacteriophages have always been central to the evolution of bacteria, although their importance has been consistently underestimated compared to transformation and conjugation. In the last 20 years, as more gene and genome sequences have become available and researchers have more accurately determined bacteriophage populations in the environment, we are gaining a clearer picture of their role in the past and potential role in the future. The transductive and lysogenic capacities of this class of bacteriophages have contributed to the evolution and shaping of emerging foodborne pathogenic bacteria through the dissemination of virulence and antibiotic resistance genes. For example, the genome sequences of Shigella dysenteriae, Escherichia coli O157:H7, and the Stxencoding bacteriophages demonstrate the critical role bacteriophage-mediated gene transfer events played in the evolution of these high-profile human pathogens. In this review, we describe the basic genetic exchange mechanisms mediated by temperate bacteriophages and how these mechanisms have been central to the dissemination of virulence genes, such as toxins and antibiotics from one species to another (the shiga-like toxins, and multiple antibiotic resistance dissemination in Salmonella are used as specific examples). Data demonstrating the role of bacteriophages in the spread of antimicrobial resistance in bacteria, including interspecies transduction, are also presented. That temperate bacteriophages play a role in the on-going evolution of emerging pathogenic bacteria is obvious, but it is also clearly an on-going process with a breadth that must be appreciated as well as studied further if we are to be able to foresee what new challenges will arise to imperil food safety. | 2005 | 16366852 |
| 9195 | 19 | 0.9927 | Complement-resistance mechanisms of bacteria. Despite more than a century of parallel research on bacteria and the complement system, relatively little is known of the mechanisms whereby pathogenic bacteria can escape complement-related opsonophagocytosis and direct killing. It is likely that pathogenicity in bacteria has arisen more accidentally than in viruses, and on the basis of selection from natural mutants rather than by outright stealing or copying of genetic codes from the host. In this review we will discuss complement resistance as one of the features that makes a bacterium a pathogen. | 1999 | 10816084 |