Browsing Det helsevitenskapelige fakultet by Author "Wagner, Theresa"

Now showing items 1-7 of 7

    • Alternative vanHAX promoters and increased vanA-plasmid copy number resurrect silenced glycopeptide resistance in Enterococcus faecium 

      Wagner, Theresa; Janice, Jessin; Sivertsen, Audun; Sjögren, Ingegerd; Sundsfjord, Arnfinn; Hegstad, Kristin (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-26)
      <i>Background</i> - Vancomycin variable enterococci (VVE) are <i>van</i>-positive isolates with a susceptible phenotype that can convert to a resistant phenotype during vancomycin selection.<p> <p><i>Objectives</i> - To describe a vancomycin-susceptible <i>vanA</i>-PCR positive ST203 VVE <i>Enterococcus faecium</i> isolate (VVE<i>Swe</i>-S) from a liver transplantation patient in Sweden which ...

    • The enterococcus cassette chromosome, a genomic variation enabler in enterococci 

      Sivertsen, Audun; James Peter, Jessin Janice; Pedersen, Torunn Annie; Wagner, Theresa; Hegstad, Joachim; Hegstad, Kristin (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-07)
      Enterococcus faecium has a highly variable genome prone to recombination and horizontal gene transfer. Here, we have identified a novel genetic island with an insertion locus and mobilization genes similar to those of staphylococcus cassette chromosome elements SCCmec. This novel element termed the enterococcus cassette chromosome (ECC) element was located in the 3′ region of rlmH and encoded large ...

    • Enterococcus faecium produces membrane vesicles containing virulence factors and antimicrobial resistance related proteins 

      Wagner, Theresa; Joshi, Bishnu; James Peter, Jessin Janice; Askarian, Fatemeh; Skalko-Basnet, Natasa; Hagestad, Ole Christian; Mekhlif, Ahmed; Wai, Sun Nyunt; Hegstad, Kristin; Johannessen, Mona (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-30)
      <i>Enterococcus faecium</i> is a commensal but also a bacteremia causing pathogen, which is inherently resistant to several antimicrobials and has a great ability to acquire new traits. Bacterial membrane vesicles (MVs) are increasingly recognized as a mode of cell-free communication and a way to deliver virulence factors and/or antimicrobial resistance determinants. These features make MVs interesting ...

    • Enterococcus faecium TIR-Domain Genes Are Part of a Gene Cluster Which Promotes Bacterial Survival in Blood 

      Wagner, Theresa; James Peter, Jessin Janice; Paganelli, Fernanda; Willems, Rob J.L.; Askarian, Fatemeh; Pedersen, Torunn Annie; Top, Janetta; de Haas, Carla; van strijp, Jos A. G.; Johannessen, Mona; Hegstad, Kristin (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-03)
      <i>Enterococcus faecium</i> has undergone a transition to a multidrug-resistant nosocomial pathogen. The population structure of <i>E. faecium</i> is characterized by a sharp distinction of clades, where the hospital-adapted lineage is primarily responsible for bacteremia. So far, factors that were identified in hospital-adapted strains and that promoted pathogenesis of nosocomial <i>E. faecium</i> ...

    • How to Be a Bad Bug: Virulence Determinants of Enterococcus faecium 

      Wagner, Theresa (Doctoral thesis; Doktorgradsavhandling, 2018-10-18)
      Enterococcus faecium is a ubiquitous bacterium that only recently emerged as a nosocomial pathogen. Infections mostly affect immunocompromised patients and multi-resistance of E. faecium often hampers treatment. This thesis focuses on determinants, which give pathogenic potential to E. faecium. In the first paper, two TirE proteins are described as novel virulence factors of E. faecium. The tirE ...

    • Reversible vancomycin susceptibility within emerging ST1421 Enterococcus faecium strains is associated with rearranged vanA-gene clusters and increased vanA plasmid copy number 

      Wagner, Theresa; Janice, Jessin; Schluz, Marc; Ballard, Susan; da Silva, Anders; Coombs, Geoffrey W; Daley, Denise; Pang, Stanley; Mowlaboccus, Shakeel; Stinear, Tim; Hegstad, Kristin; Howden, Benjamin P; Sundsfjord, Arnfinn (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-13)
      Vancomycin variable enterococci (VVE) are van-positive enterococci with a vancomycin-susceptible phenotype (VVE-S) that can convert to a resistant phenotype (VVE-R) and be selected for during vancomycin exposure. VVE-R outbreaks have been reported in Canada and Scandinavian countries. The aim of this study was to examine the presence of VVE in whole genome sequenced (WGS) Australian bacteremia ...

    • Transiently silent acquired antimicrobial resistance: an emerging challenge in susceptibility testing 

      Wagner, Theresa; Howden, Benjamin P; Sundsfjord, Arnfinn; Hegstad, Kristin (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-31)
      Acquisition and expression of antimicrobial resistance (AMR) mechanisms in bacteria are often associated with a fitness cost. Thus, evolutionary adaptation and fitness cost compensation may support the advance of subpopulations with a silent resistance phenotype when the antibiotic selection pressure is absent. However, reports are emerging on the transient nature of silent acquired AMR, describing ...