• Bacterial evolution on demand 

      Johnsen, Pål Jarle; Gama, João Alves; Harms, Klaus (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-06)
      Bacteria carry antibiotic resistant genes on movable sections of DNA that allow them to select the relevant genes on demand.
    • Cryptic β-Lactamase Evolution Is Driven by Low β-Lactam Concentrations 

      Fröhlich, Christopher; Gama, João Alves; Harms, Klaus; Hirvonen, Viivi H. A.; Lund, Bjarte Aarmo; van der Kamp, Marc W.; Johnsen, Pål Jarle; Samuelsen, Ørjan; Leiros, Hanna-Kirsti S. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-28)
      Our current understanding of how low antibiotic concentrations shape the evolution of contemporary β-lactamases is limited. Using the widespread carbapenemase OXA-48, we tested the long-standing hypothesis that selective compartments with low antibiotic concentrations cause standing genetic diversity that could act as a gateway to developing clinical resistance. Here, we subjected <i>Escherichia ...
    • Dominance between plasmids determines the extent of biofilm formation 

      Gama, João Alves; Fredheim, Elizabeth G. Aarag; Cléon, Francois Pierre Alexandre; Reis, Ana Maria; Zilhão, Rita; Dionisio, Francisco (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-26)
      Bacterial biofilms have an impact in medical and industrial environments because they often confer protection to bacteria against harmful agents, and constitute a source from which microorganisms can disperse. Conjugative plasmids can enhance bacterial ability to form biofilms because conjugative pili act as adhesion factors. However, plasmids may interact with each other, either facilitating or ...
    • Mge-cluster: a reference-free approach for typing bacterial plasmids 

      Alonso, Sergio Arredondo; Gladstone, Rebecca Ashley; Pöntinen, Anna Kaarina; Gama, João Alves; Schürch, Anita C.; Lanza, Val F.; Johnsen, Pål Jarle; Samuelsen, Ørjan; Tonkin-Hill, Gerry; Corander, Jukka (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-10)
      Extrachromosomal elements of bacterial cells such as plasmids are notorious for their importance in evolution and adaptation to changing ecology. However, high-resolution population-wide analysis of plasmids has only become accessible recently with the advent of scalable long-read sequencing technology. Current typing methods for the classification of plasmids remain limited in their scope which ...
    • Piggybacking on Niche Adaptation Improves the Maintenance of Multidrug-Resistance Plasmids 

      Kloos, Julia Maria; Gama, João Alves; Hegstad, Joachim; Samuelsen, Ørjan; Johnsen, Pål Jarle (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-24)
      The persistence of plasmids in bacterial populations represents a puzzling evolutionary problem with serious clinical implications due to their role in the ongoing antibiotic resistance crisis. Recently, major advancements have been made toward resolving this “plasmid paradox” but mainly in a nonclinical context. Here, we propose an additional explanation for the maintenance of multidrug‐resistance ...
    • Plasmid Interactions Can Improve Plasmid Persistence in Bacterial Populations 

      Gama, João Alves; Zilhão, Rita; Dionisio, Francisco (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-31)
      It is difficult to understand plasmid maintenance in the absence of selection and theoretical models predict the conditions for plasmid persistence to be limited. Plasmid-associated fitness costs decrease bacterial competitivity, while imperfect partition allows the emergence of plasmid-free cells during cell division. Although plasmid conjugative transfer allows mobility into plasmid-free cells, ...
    • Plasmid Interactions Can Improve Plasmid Persistence in Bacterial Populations 

      Gama, João Alves; Zilhão, Rita; Dionisio, Francisco (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-31)
      It is difficult to understand plasmid maintenance in the absence of selection and theoretical models predict the conditions for plasmid persistence to be limited. Plasmid-associated fitness costs decrease bacterial competitivity, while imperfect partition allows the emergence of plasmid-free cells during cell division. Although plasmid conjugative transfer allows mobility into plasmid-free cells, ...