# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 9907 | 0 | 1.0000 | Mobile Genetic Elements Associated with Antimicrobial Resistance. Strains of bacteria resistant to antibiotics, particularly those that are multiresistant, are an increasing major health care problem around the world. It is now abundantly clear that both Gram-negative and Gram-positive bacteria are able to meet the evolutionary challenge of combating antimicrobial chemotherapy, often by acquiring preexisting resistance determinants from the bacterial gene pool. This is achieved through the concerted activities of mobile genetic elements able to move within or between DNA molecules, which include insertion sequences, transposons, and gene cassettes/integrons, and those that are able to transfer between bacterial cells, such as plasmids and integrative conjugative elements. Together these elements play a central role in facilitating horizontal genetic exchange and therefore promote the acquisition and spread of resistance genes. This review aims to outline the characteristics of the major types of mobile genetic elements involved in acquisition and spread of antibiotic resistance in both Gram-negative and Gram-positive bacteria, focusing on the so-called ESKAPEE group of organisms (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., and Escherichia coli), which have become the most problematic hospital pathogens. | 2018 | 30068738 |
| 9910 | 1 | 0.9999 | Plasmid-Mediated Antibiotic Resistance and Virulence in Gram-Negatives: the Klebsiella pneumoniae Paradigm. Plasmids harbor genes coding for specific functions including virulence factors and antibiotic resistance that permit bacteria to survive the hostile environment found in the host and resist treatment. Together with other genetic elements such as integrons and transposons, and using a variety of mechanisms, plasmids participate in the dissemination of these traits, resulting in the virtual elimination of barriers among different kinds of bacteria. In this article we review the current information about the physiology of plasmids and their role in virulence and antibiotic resistance from the Gram-negative opportunistic pathogen Klebsiella pneumoniae. This bacterium has acquired multidrug resistance and is the causative agent of serious community- and hospital-acquired infections. It is also included in the recently defined ESKAPE group of bacteria that cause most U.S. hospital infections. | 2014 | 26104358 |
| 9908 | 2 | 0.9999 | Insights on the Horizontal Gene Transfer of Carbapenemase Determinants in the Opportunistic Pathogen Acinetobacter baumannii. Horizontal gene transfer (HGT) is a driving force to the evolution of bacteria. The fast emergence of antimicrobial resistance reflects the ability of genetic adaptation of pathogens. Acinetobacter baumannii has emerged in the last few decades as an important opportunistic nosocomial pathogen, in part due to its high capacity of acquiring resistance to diverse antibiotic families, including to the so-called last line drugs such as carbapenems. The rampant selective pressure and genetic exchange of resistance genes hinder the effective treatment of resistant infections. A. baumannii uses all the resistance mechanisms to survive against carbapenems but production of carbapenemases are the major mechanism, which may act in synergy with others. A. baumannii appears to use all the mechanisms of gene dissemination. Beyond conjugation, the mostly reported recent studies point to natural transformation, transduction and outer membrane vesicles-mediated transfer as mechanisms that may play a role in carbapenemase determinants spread. Understanding the genetic mobilization of carbapenemase genes is paramount in preventing their dissemination. Here we review the carbapenemases found in A. baumannii and present an overview of the current knowledge of contributions of the various HGT mechanisms to the molecular epidemiology of carbapenem resistance in this relevant opportunistic pathogen. | 2016 | 27681923 |
| 9906 | 3 | 0.9999 | Multi-resistant Gram-negative bacilli: from epidemics to endemics. PURPOSE OF REVIEW: Infections due to multi-drug resistant Gram-negative bacilli represent a worrying situation for the management of hospitalized patients. In addition, these bacteria are increasingly involved in epidemics throughout the world. This review focuses on recent data that may help to understand the emergence and dissemination of multi-drug resistant bacilli and the current trend from epidemic to endemic situations. RECENT FINDINGS: Well-established clones enhance their resistance phenotype by the acquisition of new resistant genes, via gene capture genetic units (plasmids, transposons or integrons), thus facilitating the co-selective process under different antimicrobial selective pressures and therefore the long-term persistence of organisms in selective environments. Not only resistant bacterial clones are selected, but also their genetic structures carrying resistance genes. Therefore, current epidemiology of multi-drug resistant bacilli is not only focused on bacterial clones but also on any kind of resistance gene capture units. In this scenario a multiclonal population structure of bacterial organisms corresponds to a collection of different strains sharing resistance genes carried by horizontally transferred genetic structures. As different strains tend to prefer different environments, this concept helps understand why the epidemiology of multi-drug resistant Gram-negative bacilli is moving from epidemics to endemics. SUMMARY: The emergence and spread of multi-drug resistant bacilli in the nosocomial setting should be understood in terms of a complex interplay of bacterial clonality, resistance genes and genetic structures promoting rapid dissemination of antimicrobial resistance. Intervention strategies in the forthcoming scenario should identify existing epidemic and/or endemic situations involving clonal organisms or resistance genes carried by epidemic gene capture units. | 2003 | 12861084 |
| 9882 | 4 | 0.9999 | Integrons in Enterobacteriaceae: diversity, distribution and epidemiology. Integrons are versatile gene acquisition systems that allow efficient capturing of exogenous genes and ensure their expression. Various classes of integrons possessing a wide variety of gene cassettes are ubiquitously distributed in enteric bacteria worldwide. The epidemiology of integrons associated multidrug resistance in Enterobacteriaceae is rapidly evolving. In the past two decades, the incidence of integrons in enteric bacteria has increased drastically with evolution of multiple gene cassettes, novel gene arrangements and complex chromosomal integrons such as Salmonella genomic islands. This review focuses on the distribution, versatility, spread and global trends of integrons among important members of the Enterobacteriaceae, including Escherichia coli, Klebsiella, Shigella and Salmonella, which are known to cause infections globally. Such a comprehensive understanding of integron-associated antibiotic resistance, their role in the spread of such resistance traits and their clinical relevance especially with regard to each genus individually is paramount to contain the global spread of antibiotic resistance. | 2018 | 29038087 |
| 9911 | 5 | 0.9999 | Plasmid-Mediated Antibiotic Resistance and Virulence in Gram-negatives: the Klebsiella pneumoniae Paradigm. Plasmids harbor genes coding for specific functions including virulence factors and antibiotic resistance that permit bacteria to survive the hostile environment found in the host and resist treatment. Together with other genetic elements such as integrons and transposons, and using a variety of mechanisms, plasmids participate in the dissemination of these traits resulting in the virtual elimination of barriers among different kinds of bacteria. In this article we review the current information about physiology and role in virulence and antibiotic resistance of plasmids from the gram-negative opportunistic pathogen Klebsiella pneumoniae. This bacterium has acquired multidrug resistance and is the causative agent of serious communityand hospital-acquired infections. It is also included in the recently defined ESKAPE group of bacteria that cause most of US hospital infections. | 2014 | 25705573 |
| 4313 | 6 | 0.9999 | Molecular epidemiology of clinically significant antibiotic resistance genes. Antimicrobials were first introduced into medical practice a little over 60 years ago and since that time resistant strains of bacteria have arisen in response to the selective pressure of their use. This review uses the paradigm of the evolution and spread of beta-lactamases and in particular beta-lactamases active against antimicrobials used to treat Gram-negative infections. The emergence and evolution particularly of CTX-M extended-spectrum beta-lactamases (ESBLs) is described together with the molecular mechanisms responsible for both primary mutation and horizontal gene transfer. Reference is also made to other significant antibiotic resistance genes, resistance mechanisms in Gram-negative bacteria, such as carbepenamases, and plasmid-mediated fluoroquinolone resistance. The pathogen Staphylococcus aureus is reviewed in detail as an example of a highly successful Gram-positive bacterial pathogen that has acquired and developed resistance to a wide range of antimicrobials. The role of selective pressures in the environment as well as the medical use of antimicrobials together with the interplay of various genetic mechanisms for horizontal gene transfer are considered in the concluding part of this review. | 2008 | 18311156 |
| 4132 | 7 | 0.9999 | Mobilization of transposons : rationale and techniques for detection. The ability to share genetic information with other bacteria represents one of the most important adaptive mechanisms available to bacteria pathogenic for humans. The exchange of many different types of genetic information appears to occur frequently and exchange of determinants responsible for antimicrobial resistance is the best studied, since the movements of resistance determinants are easy to follow and the clinical importance of resistance dissemination is so great. The most common vehicles by which bacteria exchange resistance determinants are plasmids and transposons. | 2001 | 21374427 |
| 9894 | 8 | 0.9998 | Mechanisms of Evolution in High-Consequence Drug Resistance Plasmids. The dissemination of resistance among bacteria has been facilitated by the fact that resistance genes are usually located on a diverse and evolving set of transmissible plasmids. However, the mechanisms generating diversity and enabling adaptation within highly successful resistance plasmids have remained obscure, despite their profound clinical significance. To understand these mechanisms, we have performed a detailed analysis of the mobilome (the entire mobile genetic element content) of a set of previously sequenced carbapenemase-producing Enterobacteriaceae (CPE) from the National Institutes of Health Clinical Center. This analysis revealed that plasmid reorganizations occurring in the natural context of colonization of human hosts were overwhelmingly driven by genetic rearrangements carried out by replicative transposons working in concert with the process of homologous recombination. A more complete understanding of the molecular mechanisms and evolutionary forces driving rearrangements in resistance plasmids may lead to fundamentally new strategies to address the problem of antibiotic resistance. IMPORTANCE: The spread of antibiotic resistance among Gram-negative bacteria is a serious public health threat, as it can critically limit the types of drugs that can be used to treat infected patients. In particular, carbapenem-resistant members of the Enterobacteriaceae family are responsible for a significant and growing burden of morbidity and mortality. Here, we report on the mechanisms underlying the evolution of several plasmids carried by previously sequenced clinical Enterobacteriaceae isolates from the National Institutes of Health Clinical Center (NIH CC). Our ability to track genetic rearrangements that occurred within resistance plasmids was dependent on accurate annotation of the mobile genetic elements within the plasmids, which was greatly aided by access to long-read DNA sequencing data and knowledge of their mechanisms. Mobile genetic elements such as transposons and integrons have been strongly associated with the rapid spread of genes responsible for antibiotic resistance. Understanding the consequences of their actions allowed us to establish unambiguous evolutionary relationships between plasmids in the analysis set. | 2016 | 27923922 |
| 4134 | 9 | 0.9998 | Plasmid-Mediated Antimicrobial Resistance in Staphylococci and Other Firmicutes. In staphylococci and other Firmicutes, resistance to numerous classes of antimicrobial agents, which are commonly used in human and veterinary medicine, is mediated by genes that are associated with mobile genetic elements. The gene products of some of these antimicrobial resistance genes confer resistance to only specific members of a certain class of antimicrobial agents, whereas others confer resistance to the entire class or even to members of different classes of antimicrobial agents. The resistance mechanisms specified by the resistance genes fall into any of three major categories: active efflux, enzymatic inactivation, and modification/replacement/protection of the target sites of the antimicrobial agents. Among the mobile genetic elements that carry such resistance genes, plasmids play an important role as carriers of primarily plasmid-borne resistance genes, but also as vectors for nonconjugative and conjugative transposons that harbor resistance genes. Plasmids can be exchanged by horizontal gene transfer between members of the same species but also between bacteria belonging to different species and genera. Plasmids are highly flexible elements, and various mechanisms exist by which plasmids can recombine, form cointegrates, or become integrated in part or in toto into the chromosomal DNA or into other plasmids. As such, plasmids play a key role in the dissemination of antimicrobial resistance genes within the gene pool to which staphylococci and other Firmicutes have access. This chapter is intended to provide an overview of the current knowledge of plasmid-mediated antimicrobial resistance in staphylococci and other Firmicutes. | 2014 | 26104453 |
| 4133 | 10 | 0.9998 | Importance of integrons in the diffusion of resistance. Horizontal transfer of resistance genes is a successful mechanism for the transmission and dissemination of multiple drug resistance among bacterial pathogens. The impact of horizontally transmitted genetic determinants in the evolution of resistance is particularly evident when resistance genes are physically associated in clusters and transferred en bloc to the recipient cell. Recent advances in the molecular characterisation of antibiotic resistance mechanisms have highlighted the existence of genetic structures. called integrons, involved in the acquisition of resistance genes. These DNA elements have frequently been reported in multi-drug resistant strains isolated from animals and humans, and are located either on the bacterial chromosome or on broad-host-range plasmids. The role of integrons in the development of multiple resistance relies on their unique capacity to cluster and express drug resistance genes. Moreover, the spread of resistance genes among different replicons and their exchange between plasmid and bacterial chromosome are facilitated by the integration of integrons into transposable elements. The association of a highly efficient gene capture and expression system, together with the capacity for vertical and horizontal transmission of resistance genes represents a powerful weapon used by bacteria to combat the assault of antibiotics. | 2001 | 11432416 |
| 4142 | 11 | 0.9998 | Antimicrobial Resistance in Pasteurellaceae of Veterinary Origin. Members of the highly heterogeneous family Pasteurellaceae cause a wide variety of diseases in humans and animals. Antimicrobial agents are the most powerful tools to control such infections. However, the acquisition of resistance genes, as well as the development of resistance-mediating mutations, significantly reduces the efficacy of the antimicrobial agents. This article gives a brief description of the role of selected members of the family Pasteurellaceae in animal infections and of the most recent data on the susceptibility status of such members. Moreover, a review of the current knowledge of the genetic basis of resistance to antimicrobial agents is included, with particular reference to resistance to tetracyclines, β-lactam antibiotics, aminoglycosides/aminocyclitols, folate pathway inhibitors, macrolides, lincosamides, phenicols, and quinolones. This article focusses on the genera of veterinary importance for which sufficient data on antimicrobial susceptibility and the detection of resistance genes are currently available (Pasteurella, Mannheimia, Actinobacillus, Haemophilus, and Histophilus). Additionally, the role of plasmids, transposons, and integrative and conjugative elements in the spread of the resistance genes within and beyond the aforementioned genera is highlighted to provide insight into horizontal dissemination, coselection, and persistence of antimicrobial resistance genes. The article discusses the acquisition of diverse resistance genes by the selected Pasteurellaceae members from other Gram-negative or maybe even Gram-positive bacteria. Although the susceptibility status of these members still looks rather favorable, monitoring of their antimicrobial susceptibility is required for early detection of changes in the susceptibility status and the newly acquired/developed resistance mechanisms. | 2018 | 29916344 |
| 9909 | 12 | 0.9998 | Enterobacter aerogenes and Enterobacter cloacae; versatile bacterial pathogens confronting antibiotic treatment. Enterobacter aerogenes and E. cloacae have been reported as important opportunistic and multiresistant bacterial pathogens for humans during the last three decades in hospital wards. These Gram-negative bacteria have been largely described during several outbreaks of hospital-acquired infections in Europe and particularly in France. The dissemination of Enterobacter sp. is associated with the presence of redundant regulatory cascades that efficiently control the membrane permeability ensuring the bacterial protection and the expression of detoxifying enzymes involved in antibiotic degradation/inactivation. In addition, these bacterial species are able to acquire numerous genetic mobile elements that strongly contribute to antibiotic resistance. Moreover, this particular fitness help them to colonize several environments and hosts and rapidly and efficiently adapt their metabolism and physiology to external conditions and environmental stresses. Enterobacter is a versatile bacterium able to promptly respond to the antibiotic treatment in the colonized patient. The balance of the prevalence, E. aerogenes versus E. cloacae, in the reported hospital infections during the last period, questions about the horizontal transmission of mobile elements containing antibiotic resistance genes, e.g., the efficacy of the exchange of resistance genes Klebsiella pneumoniae to Enterobacter sp. It is also important to mention the possible role of antibiotic use in the treatment of bacterial infectious diseases in this E. aerogenes/E. cloacae evolution. | 2015 | 26042091 |
| 4046 | 13 | 0.9998 | Horizontal Gene Transfer and Its Association with Antibiotic Resistance in the Genus Aeromonas spp. The evolution of multidrug resistant bacteria to the most diverse antimicrobials known so far pose a serious problem to global public health. Currently, microorganisms that develop resistant phenotypes to multiple drugs are associated with high morbidity and mortality. This resistance is encoded by a group of genes termed 'bacterial resistome', divided in intrinsic and extrinsic resistome. The first one refers to the resistance displayed on an organism without previous exposure to an antibiotic not involving horizontal genetic transfer, and it can be acquired via mutations. The latter, on the contrary, is acquired exclusively via horizontal genetic transfer involving mobile genetic elements that constitute the 'bacterial mobilome'. This transfer is mediated by three different mechanisms: transduction, transformation, and conjugation. Recently, a problem of public health due to implications in the emergence of multi-drug resistance in Aeromonas spp. strains in water environments has been described. This is derived from the genetic material transfer via conjugation events. This is important, since bacteria that have acquired antibiotic resistance in natural environments can cause infections derived from their ingestion or direct contact with open wounds or mucosal tissue, which in turn, by their resistant nature, makes their eradication complex. Implications of the emergence of resistance in Aeromonas spp. by horizontal gene transfer on public health are discussed. | 2019 | 31540466 |
| 9895 | 14 | 0.9998 | Clinically Relevant Plasmid-Host Interactions Indicate that Transcriptional and Not Genomic Modifications Ameliorate Fitness Costs of Klebsiella pneumoniae Carbapenemase-Carrying Plasmids. The rapid dissemination of antimicrobial resistance (AMR) around the globe is largely due to mobile genetic elements, such as plasmids. They confer resistance to critically important drugs, including extended-spectrum beta-lactams, carbapenems, and colistin. Large, complex resistance plasmids have evolved alongside their host bacteria. However, much of the research on plasmid-host evolution has focused on small, simple laboratory plasmids in laboratory-adapted bacterial hosts. These and other studies have documented mutations in both host and plasmid genes which occur after plasmid introduction to ameliorate fitness costs of plasmid carriage. We describe here the impact of two naturally occurring variants of a large AMR plasmid (pKpQIL) on a globally successful pathogen. In our study, after pKpQIL plasmid introduction, no changes in coding domain sequences were observed in their natural host, Klebsiella pneumoniae However, significant changes in chromosomal and plasmid gene expression may have allowed the bacterium to adapt to the acquisition of the AMR plasmid. We hypothesize that this was sufficient to ameliorate the associated fitness costs of plasmid carriage, as pKpQIL plasmids were maintained without selection pressure. The dogma that removal of selection pressure (e.g., antimicrobial exposure) results in plasmid loss due to bacterial fitness costs is not true for all plasmid/host combinations. We also show that pKpQIL impacted the ability of K. pneumoniae to form a biofilm, an important aspect of virulence. This study used highly relevant models to study the interaction between AMR plasmids and pathogens and revealed striking differences from results of studies done on laboratory-adapted plasmids and strains.IMPORTANCE Antimicrobial resistance is a serious problem facing society. Many of the genes that confer resistance can be shared between bacteria through mobile genetic elements, such as plasmids. Our work shows that when two clinically relevant AMR plasmids enter their natural host bacteria, there are changes in gene expression, rather than changes to gene coding sequences. These changes in gene expression ameliorate the potential fitness costs of carriage of these AMR plasmids. In line with this, the plasmids were stable within their natural host and were not lost in the absence of selective pressure. We also show that better understanding of the impact of resistance plasmids on fundamental pathogen biology, including biofilm formation, is crucial for fighting drug-resistant infections. | 2018 | 29691332 |
| 4876 | 15 | 0.9998 | Epidemiology of mobile colistin resistance (mcr) genes in aquatic environments. Colistin is one of the last-line therapies against multidrug-resistant Gram-negative pathogens, especially carbapenemase-producing isolates, making resistance to this compound a major global public-health crisis. Until recently, colistin resistance in Gram-negative bacteria was known to arise only by chromosomal mutations. However, a plasmid-mediated colistin resistance mechanism was described in late 2015. This mechanism is encoded by different mobile colistin resistance (mcr) genes that encode phosphoethanolamine (pEtN) transferases. These enzymes catalyse the addition of a pEtN moiety to lipid A in the bacterial outer membrane leading to colistin resistance. MCR-producing Gram-negative bacteria have been largely disseminated worldwide. However, their environmental dissemination has been underestimated. Indeed, water environments act as a connecting medium between different environments, allowing them to play a crucial role in the spread of antibiotic resistance between the natural environment and humans and other animals. For a better understanding of the role of such environments as reservoirs and/or dissemination routes of mcr genes, this review discusses primarily the various water habitats contributing to the spread of antibiotic resistance. Thereafter, we provide an overview of existing knowledge regarding the global epidemiology of mcr genes in water environments. This review confirms the global distribution of mcr genes in several water environments, including wastewater from different origins, surface water and tap water, making these environments reservoirs and dissemination routes of concern for this resistance mechanism. | 2021 | 34438108 |
| 4323 | 16 | 0.9998 | Current trends of human infections and antibiotic resistance of the genus Shewanella. Shewanella spp. are commonly known as environmental bacteria and are most frequently isolated from aquatic areas. Currently, diseases syndromes and multidrug resistance have increasingly been reported in the genus Shewanella. Some species are associated with various infections, such as skin and soft tissue infections, as well as bacteremia. Generally, these bacteria are opportunistic and mostly affect people with an impaired immune system. This genus is also a probable vehicle and progenitor of antibiotic resistance genes. In fact, several resistance genes and mobile genetic elements have been identified in some resistant species isolated from environmental or clinical settings. These genes confer resistance to different antibiotic classes, including those used in therapies such as β-lactams and quinolones, and are generally located on the chromosome. Recently, a multidrug-resistant (MDR) plasmid harboring several drug resistance genes associated with transposons and integrons has been identified in Shewanella xiamenensis. These antibiotic resistance genes can circulate in the environment and contribute to the emergence of antibiotic resistance. This review describes different aspects of Shewanella, focusing on the infections caused by this genus, as well as their role in the propagation of antibiotic resistance via mobile genetic elements. | 2017 | 28299457 |
| 4423 | 17 | 0.9998 | Inactivation of antibiotics and the dissemination of resistance genes. The emergence of multidrug-resistant bacteria is a phenomenon of concern to the clinician and the pharmaceutical industry, as it is the major cause of failure in the treatment of infectious diseases. The most common mechanism of resistance in pathogenic bacteria to antibiotics of the aminoglycoside, beta-lactam (penicillins and cephalosporins), and chloramphenicol types involves the enzymic inactivation of the antibiotic by hydrolysis or by formation of inactive derivatives. Such resistance determinants most probably were acquired by pathogenic bacteria from a pool of resistance genes in other microbial genera, including antibiotic-producing organisms. The resistance gene sequences were subsequently integrated by site-specific recombination into several classes of naturally occurring gene expression cassettes (typically "integrons") and disseminated within the microbial population by a variety of gene transfer mechanisms. Although bacterial conjugation once was believed to be restricted in host range, it now appears that this mechanism of transfer permits genetic exchange between many different bacterial genera in nature. | 1994 | 8153624 |
| 4235 | 18 | 0.9998 | Molecular mechanisms of antibacterial multidrug resistance. Treatment of infections is compromised worldwide by the emergence of bacteria that are resistant to multiple antibiotics. Although classically attributed to chromosomal mutations, resistance is most commonly associated with extrachromosomal elements acquired from other bacteria in the environment. These include different types of mobile DNA segments, such as plasmids, transposons, and integrons. However, intrinsic mechanisms not commonly specified by mobile elements-such as efflux pumps that expel multiple kinds of antibiotics-are now recognized as major contributors to multidrug resistance in bacteria. Once established, multidrug-resistant organisms persist and spread worldwide, causing clinical failures in the treatment of infections and public health crises. | 2007 | 17382878 |
| 4149 | 19 | 0.9998 | Antibiotic resistance genes from the environment: a perspective through newly identified antibiotic resistance mechanisms in the clinical setting. Soil bacteria may contain antibiotic resistance genes responsible for different mechanisms that permit them to overcome the natural antibiotics present in the environment. This gene pool has been recently named the 'resistome', and its components can be mobilized into the microbial community affecting humans because of the participation of genetic platforms that efficiently facilitate the mobilization and maintenance of these resistance genes. Evidence for this transference has been suggested or demonstrated with newly identified widespread genes in multidrug-resistant bacteria. These resistance genes include those responsible for ribosomal methylases affecting aminoglycosides (armA, rtmB), methyltransferases affecting linezolid (cfr) or plasmid-mediated efflux pumps conferring low-level fluoroquinolone resistance (qepA), all of which are associated with antibiotic-producing bacteria. In addition, resistance genes whose ancestors have been identified in environmental isolates that are not recognized as antibiotic producers have also been recently detected. These include the qnr and the bla(CTX) genes compromising the activity of fluoroquinolones and extended-spectrum cephalosporins, respectively. The application of metagenomic tools and phylogenetic analysis will facilitate future identification of other new resistance genes and their corresponding ancestors in environmental bacteria, and will enable further exploration of the concept of the resistome as being a unique reservoir of antibiotic resistance genes and genetic elements participating in resistance gene transfer. | 2009 | 19220348 |