Apparent nosocomial adaptation of Enterococcus faecalis predates the modern hospital era.
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ABSTRACT:
SUBMITTER: Pontinen AK
PROVIDER: S-EPMC7943827 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Emerging antibiotic resistance among clinically relevant bacteria, paired with their ability to form biofilms on medical and technical devices, represents a serious problem in terms of effective and long-term decontamination in health care environments and gives rise to an urgent need for new antimicrobial materials. Here we present the first study of the impact of AGXX®, a novel broad-spectrum antimicrobial surface coating consisting of micro galvanic elements formed by silver and ruthenium, on the transcriptome of the nosocomial pathogen Enterococcus faecalis. E. faecalis was subjected to metal stress by growing it for different periods of time in the presence of AGXX® or silver-coated steel meshes. Subsequently, total RNA was isolated and next-generation RNA sequencing was performed to analyze variations in gene expression levels in the presence of the antimicrobial materials with focus on known stress genes. Exposure to AGXX® had a large impact on the transcriptome of E. faecalis. After 24 minutes almost 1/5 of the E. faecalis genome displayed differential expression. At each time-point the cop operon was strongly up-regulated, providing indirect evidence for the presence of free Ag+-ions. Moreover, exposure to AGXX® induced a broad general stress response in E. faecalis. Genes coding for the chaperones GroEL and GroES as well as the Clp proteases ClpE and ClpB were among the top up-regulated heat shock genes. Furthermore, differential expression of genes coding for thioredoxin, superoxide dismutase and glutathione synthetase indicates a high level of oxidative stress. We postulate a mechanism of action where the combination of Ag+-ions and reactive oxygen species generated by AGXX® results in a synergistic antimicrobial effect, which is superior to that of conventional silver coatings.
2016-03-16 | GSE79250 | GEO
Project description:In this study, we present a trilocus sequence typing (TLST) scheme based on intragenic regions of two antigenic genes, ace and salA (encoding a collagen/laminin adhesin and a cell wall-associated antigen, respectively), and a gene associated with antibiotic resistance, lsa (encoding a putative ABC transporter), for subspecies differentiation of Enterococcus faecalis. Each of the alleles was analyzed using 50 E. faecalis isolates representing 42 diverse multilocus sequence types (ST(M); based on seven housekeeping genes) and four groups of clonally linked (by pulsed-field gel electrophoresis [PFGE]) isolates. The allelic profiles and/or concatenated sequences of the three genes agreed with multilocus sequence typing (MLST) results for typing of 49 of the 50 isolates; in addition to the one exception, two isolates were found to have identical TLST types but were single-locus variants (differing by a single nucleotide) by MLST and were therefore also classified as clonally related by MLST. TLST was also comparable to PFGE for establishing short-term epidemiological relationships, typing all isolates classified as clonally related by PFGE with the same type. TLST was then applied to representative isolates (of each PFGE subtype and isolation year) of a collection of 48 hospital isolates and demonstrated the same relationships between isolates of an outbreak strain as those found by MLST and PFGE. In conclusion, the TLST scheme described here was shown to be successful for investigating short-term epidemiology in a hospital setting and may provide an alternative to MLST for discriminating isolates.
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Project description:Comparative genomic hybridization of 15 strains isolated in European hospital environments and selected for CGH based on MLST sequence types
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Project description:Emerging antibiotic resistance among clinically relevant bacteria, paired with their ability to form biofilms on medical and technical devices, represents a serious problem in terms of effective and long-term decontamination in health care environments and gives rise to an urgent need for new antimicrobial materials. Here we present the first study of the impact of AGXX®, a novel broad-spectrum antimicrobial surface coating consisting of micro galvanic elements formed by silver and ruthenium, on the transcriptome of the nosocomial pathogen Enterococcus faecalis. E. faecalis was subjected to metal stress by growing it for different periods of time in the presence of AGXX® or silver-coated steel meshes. Subsequently, total RNA was isolated and next-generation RNA sequencing was performed to analyze variations in gene expression levels in the presence of the antimicrobial materials with focus on known stress genes. Exposure to AGXX® had a large impact on the transcriptome of E. faecalis. After 24 minutes almost 1/5 of the E. faecalis genome displayed differential expression. At each time-point the cop operon was strongly up-regulated, providing indirect evidence for the presence of free Ag+-ions. Moreover, exposure to AGXX® induced a broad general stress response in E. faecalis. Genes coding for the chaperones GroEL and GroES as well as the Clp proteases ClpE and ClpB were among the top up-regulated heat shock genes. Furthermore, differential expression of genes coding for thioredoxin, superoxide dismutase and glutathione synthetase indicates a high level of oxidative stress. We postulate a mechanism of action where the combination of Ag+-ions and reactive oxygen species generated by AGXX® results in a synergistic antimicrobial effect, which is superior to that of conventional silver coatings. Gene expression analysis of Enterococcus faecalis 12030 either subjected to metal stress by exposure to an antimicrobial AGXX®- or Ag-coated V2A steel mesh or exposed to an uncoated V2A steel mesh or left untreated performing RNA Sequencing with an Ion ProtonTM Sequencer and subsequent data analysis with a T-REx RNA-Sequencing expression analysis pipeline.
2016-03-16 | E-GEOD-79250 | biostudies-arrayexpress
Project description:Vancomycin-resistant Enterococcus faecalis (VREfs) is an important nosocomial pathogen1,2. We undertook whole genome sequencing of E. faecalis associated with bloodstream infection in the UK and Ireland over more than a decade to determine the population structure and genetic associations with hospital adaptation. Three lineages predominated in the population, two of which (L1 and L2) were nationally distributed, and one (L3) geographically restricted. Genome comparison with a global collection identified that L1 and L3 were also present in the USA, but were genetically distinct. Over 90% of VREfs belonged to L1-L3, with resistance acquired and lost multiple times in L1 and L2, but only once followed by clonal expansion in L3. Putative virulence and antibiotic resistance genes were over-represented in L1, L2 and L3 isolates combined, versus the remainder. Each of the three main lineages contained a mixture of vancomycin-resistant and -susceptible E. faecalis (VSEfs), which has important implications for infection control and antibiotic stewardship.
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Project description:Enterococcus faecalis and faecium are two major representative clinical strains of the Enterococcus genus and are sadly notorious to be part of the top agents responsible for nosocomial infections. Despite their critical implication in worldwide public healthcare, essential and available resources such as deep transcriptome annotations remain poor, which also limits our understanding of post-transcriptional control small regulatory RNA (sRNA) functions in these bacteria. Here, using the dRNA-seq technique in combination with ANNOgesic analysis, we successfully mapped and annotated transcription start sites (TSS) of both E. faecalis V583 and E. faecium AUS0004 at single nucleotide resolution. Analyzing bacteria in late exponential phase, we capture ~40% (E. faecalis) and 43% (E. faecium) of the annotated protein-coding genes, determine 5' and 3' UTR (untranslated region) length, and detect instances of leaderless mRNAs. The transcriptome maps revealed sRNA candidates in both bacteria, some found in previous studies and new ones. Expression of candidate sRNAs is being confirmed under biologically relevant environmental conditions. This comprehensive global TSS mapping atlas provides a valuable resource for RNA biology and gene expression analysis in the Enterococci. It can be accessed online at www.helmholtz-hiri.de/en/datasets/enterococcus through an instance of the genomic viewer JBrowse.
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Project description:BackgroundEnterococcus faecalis plays a dual role in human ecology, predominantly existing as a commensal in the alimentary canal, but also as an opportunistic pathogen that frequently causes nosocomial infections like bacteremia. A number of virulence factors that contribute to the pathogenic potential of E. faecalis have been established. However, the process in which E. faecalis gains access to the bloodstream and establishes a persistent infection is not well understood.Methodology/principal findingsTo enhance our understanding of how this commensal bacterium adapts during a bloodstream infection and to examine the interplay between genes we designed an in vitro experiment using genome-wide microarrays to investigate what effects the presence of and growth in blood have on the transcriptome of E. faecalis strain V583. We showed that growth in both 2xYT supplemented with 10% blood and in 100% blood had a great impact on the transcription of many genes in the V583 genome. We identified several immediate changes signifying cellular processes that might contribute to adaptation and growth in blood. These include modulation of membrane fatty acid composition, oxidative and lytic stress protection, acquisition of new available substrates, transport functions including heme/iron transporters and genes associated with virulence in E. faecalis.Conclusions/significanceThe results presented here reveal that cultivation of E. faecalis in blood in vitro has a profound impact on its transcriptome, which includes a number of virulence traits. Observed regulation of genes and pathways revealed new insight into physiological features and metabolic capacities which enable E. faecalis to adapt and grow in blood. A number of the regulated genes might potentially be useful candidates for development of new therapeutic approaches for treatment of E. faecalis infections.
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Project description:With increasing numbers of hospital-acquired antibiotic resistant infections each year and staggering health care costs, there is a clear need for new antimicrobial agents, as well as novel strategies to extend their clinical efficacy. While genomic studies have provided a wealth of information about the alleles associated with adaptation to antibiotics, they do not provide essential information about the relative importance of genomic changes, their order of appearance, or potential epistatic relationships between adaptive changes. Here we used quantitative experimental evolution of a single polymorphic population in continuous culture with whole-genome sequencing and allelic frequency measurements to study daptomycin (DAP) resistance in the vancomycin-resistant clinical pathogen Enterococcus faecalis S613. Importantly, we sustained both planktonic and nonplanktonic (i.e., biofilm) populations in coculture as the concentration of antibiotic was raised, facilitating the development of more ecological complexity than is typically observed in laboratory evolution. Quantitative experimental evolution revealed a clear order and hierarchy of genetic changes leading to resistance, the signaling and metabolic pathways responsible, and the relative importance of these mutations to the evolution of DAP resistance. Despite the relative simplicity of this ex vivo approach compared to the ecological complexity of the human body, we showed that experimental evolution allows for rapid identification of clinically relevant adaptive molecular pathways and new targets for drug design in pathogens.
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Project description:Mechanisms that enable Enterococcus to cope with different environmental stresses and their contribution to the switch from commensalism to pathogenicity of this organism are still poorly understood. Maintenance of intracellular homeostasis of metal ions is crucial for survival of these bacteria. In particular Zn(2+), Mn(2+) and Cu(2+) are very important metal ions as they are co-factors of many enzymes, are involved in oxidative stress defense and have a role in the immune system of the host. Their concentrations inside the human body vary hugely, which makes it imperative for Enterococcus to fine-tune metal ion homeostasis in order to survive inside the host and colonize it. Little is known about metal regulation in Enterococcus faecalis. Here we present the first genome-wide description of gene expression of E. faecalis V583 growing in the presence of high concentrations of zinc, manganese or copper ions. The DNA microarray experiments revealed that mostly transporters are involved in the responses of E. faecalis to prolonged exposure to high metal concentrations although genes involved in cellular processes, in energy and amino acid metabolisms and genes related to the cell envelope also seem to play important roles.
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