Project description:The enterococci comprise a genus of 49 low-GC content Gram-positive commensal species within the Firmicutes phylum that are known to occupy diverse habitats, notably the gastrointestinal core microbiota of nearly every phylum, including human. Of particular clinical relevance are two rogue species of enterococci, Enterococcus faecalis and the distantly related Enterococcus faecium, standing among the nefarious multi-drug resistant and hospital-acquired pathogens. Despite increasing evidence for RNA-based regulation in the enterococci, including regulation of virulence factors, their transcriptome structure and arsenal of regulatory small sRNAs (sRNAs) are not thoroughly understood. Using dRNA-seq, we have mapped at single-nucleotide resolution the primary transcriptomes of E. faecalis V583 and E. faecium AUS0004. We identified 2517 and 2771 transcription start sites (TSS) in E. faecalis and E. faecium, respectively. Based on the identified TSS, we created a global map of s70 promoter motifs. We also revealed features of 5’ and 3’UTRs across the genomes. The transcriptome maps also predicted 150 and 128 sRNA candidates in E. faecalis and E. faecium, respectively, some of which have been identified in previous studies and many of which are new. Finally, we validated several of the predicted sRNAs by Northern Blot in biologically relevant conditions. Comprehensive TSS mapping of two representative strains will provide a valuable resource for the continued development of RNA biology in the Enterococci.
Project description:Young adult N2 Caenorhabditis elegans were infected with Enterococcus faecalis or Enterococcus faecium for 8 h to determine the transcriptional host response to each enterococcal species. Analysis of differential gene expression in C. elegans young adults exposed to four different bacteria: heat-killed Escherichia coli strain OP50 (control), wild-type E. faecalis MMH594, wild-type E. faecium E007, or Bacillus subtilis PY79 (sigF::kan). Samples were analyzed at 8 hours after exposure to the different bacteria. These studies identified C. elegans genes induced by pathogen infection. Brain-heart infusion agar plates (10 ug/ml kanamycin) were used.
Project description:The success of Enterococcus faecium and E. faecalis evolving as multi-resistant nosocomial pathogens is associated with their ability to acquire and share adaptive traits, including mobile genetic elements (MGE) encoding antimicrobial resistance. Here, we define the mobilome in representative successful hospital associated genetic lineages, E. faecium ST17 (n=10) and ST78 (n=10), E. faecalis ST6 (n=10) and ST40 (n=10) using DNA microarray analyses. The hybridization patterns of 272 targets representing plasmid backbones (n=85), transposable elements (n=85), resistance determinants (n=67), prophages (n=29), and CRISPR-cas sequences (n=6) separated the strains according to species, and for E. faecalis also according to STs. Although plasmids belonging to the RCR-, Rep_3-, RepA_N- and Inc18-families were well represented with no significant differences in prevalence, the presence of specific replicon classes differed highly between the species; E. faecium was dominated by rep17/pRUM, rep2/pRE25, rep14/EFNP1 and rep20/pLG1 and E. faecalis by rep9/pCF10, rep2/pRE25 and rep7. Tn916-elements conferring tetracycline resistance (tetM) were found in all E. faecalis strains, but only in two E. faecium strains. A significant higher prevalence of IS256-, IS3-, ISL3-, IS200/IS605-, IS110-, IS982-, and IS4-transposases were detected in E. faecium, and of IS110-, IS982- and IS1182-transposases in E. faecalis ST6 compared to ST40. Notably, the transposases of IS981, ISEfm1 and IS1678 which have only been reported in few enterococcal isolates, were well represented in the E. faecium strains. E. faecalis ST40 strains harboured possible functional CRISPR-Cas systems, and still resistance and prophage sequences were generally well represented. Gene targets defined as the enterococcal mobilome, including plasmids, IS elements and transposons, resistance determinants, prophage sequences and CRISPR-Cas systems were highly prevalent, underlining their potential importance in the evolution of hospital associated STs. An association between axe-txe to the RepA_N-family and ω-ε-ζ to the Inc18-family, implicates the contribution of TA-systems in stable plasmid maintenance carrying virulence and resistance determinants in enterococci. The concurrent presence of defined MGE and their associated resistance markers was generally confirmed and illustrates the importance of horizontal gene transfer in the development of multidrug resistant enterococci.
Project description:We investigated the RNA-protein interactome of Enterococcus faecalis V583 and Enterococcus faecium Aus0004 by native gradient fractionation of complexes coupled to RNA-sequencing. Whole bacterial cell lysates were analysed by size and density in a glycerol gradient. At native conditions, RNA-protein complexes stay intact and sediment as a whole. Sedimentation profiles of individual RNAs appear correlated in case of interaction in a complex. The profile of KhpB caught our attention and we determined its RNA interactome by immunoprecipitation that suggests a role at the post-transcriptional level, binding notably several tRNAs, sRNAs, and 3’UTRs.
Project description:The success of Enterococcus faecium and E. faecalis evolving as multi-resistant nosocomial pathogens is associated with their ability to acquire and share adaptive traits, including mobile genetic elements (MGE) encoding antimicrobial resistance. Here, we define the mobilome in representative successful hospital associated genetic lineages, E. faecium ST17 (n=10) and ST78 (n=10), E. faecalis ST6 (n=10) and ST40 (n=10) using DNA microarray analyses. The hybridization patterns of 272 targets representing plasmid backbones (n=85), transposable elements (n=85), resistance determinants (n=67), prophages (n=29), and CRISPR-cas sequences (n=6) separated the strains according to species, and for E. faecalis also according to STs. Although plasmids belonging to the RCR-, Rep_3-, RepA_N- and Inc18-families were well represented with no significant differences in prevalence, the presence of specific replicon classes differed highly between the species; E. faecium was dominated by rep17/pRUM, rep2/pRE25, rep14/EFNP1 and rep20/pLG1 and E. faecalis by rep9/pCF10, rep2/pRE25 and rep7. Tn916-elements conferring tetracycline resistance (tetM) were found in all E. faecalis strains, but only in two E. faecium strains. A significant higher prevalence of IS256-, IS3-, ISL3-, IS200/IS605-, IS110-, IS982-, and IS4-transposases were detected in E. faecium, and of IS110-, IS982- and IS1182-transposases in E. faecalis ST6 compared to ST40. Notably, the transposases of IS981, ISEfm1 and IS1678 which have only been reported in few enterococcal isolates, were well represented in the E. faecium strains. E. faecalis ST40 strains harboured possible functional CRISPR-Cas systems, and still resistance and prophage sequences were generally well represented. Gene targets defined as the enterococcal mobilome, including plasmids, IS elements and transposons, resistance determinants, prophage sequences and CRISPR-Cas systems were highly prevalent, underlining their potential importance in the evolution of hospital associated STs. An association between axe-txe to the RepA_N-family and M-OM-^I-M-NM-5-M-NM-6 to the Inc18-family, implicates the contribution of TA-systems in stable plasmid maintenance carrying virulence and resistance determinants in enterococci. The concurrent presence of defined MGE and their associated resistance markers was generally confirmed and illustrates the importance of horizontal gene transfer in the development of multidrug resistant enterococci. All together 272 DNA targets representing mobile genetic elements and antimicrobial resistance determinants associated with enterococci were spotted on a CustomArray 4x2K microarray from CustomArray Inc. Each fourplex microarray slide contain four identical sectors that were stripped and re-hybridized up to six times. Each target was represented by 1-5 probes each. The total of 1250 probes were Tm balanced by altering their lenght between 35 and 40 nucleotides. Total DNA of 41 samples were hybridized and a control strain, the fully sequenced E. faecalis V585, was included in one of the four sectors on each slide in each set of hybridization to monitor the overall array and hybridization quality.
Project description:Small non coding RNA molecules (sncRNAs) are key mediators of virulence and stress inducible gene expressions in some pathogens. In this work we identify sncRNAs in the Gram positive opportunistic pathogen Enterococcus faecalis. Enterococcus faecalis. We characterized 11 sncRNAs by tiling microarray analysis, 5’ and 3’ RACE-PCR, and Northern blot analysis. Six sncRNAs were specifically expressed at exponential phase, two sncRNAs were observed at stationary phase, and three were detected during both phases. This is the first experimental genome-wide identification of sncRNAs in E. faecalis and provides impetus to the understanding of gene regulation in this important human pathogen.
Project description:To further investigate the homeostatic response of E. faecalis to Fe exposure, we examine the whole-genome transcriptional response of wild-type (WT) exposed to non toxic Fe excess. This experiment correspond the work titled Transcriptomic response of Enterococcus faecalis to iron excess (work in preparation) A four chip study using total RNA recovered from four separate wild-type cultures of Enterococcus faecalis OG1RF, two controls samples (N medium growth) and two iron samples (N medium gowth with 0.5 mM Fe-NTA). Each chip measures the expression level of 3,114 genome genes from Enterococcus faecalis strain V583 (A7980-00-01).