The fish pathogen Francisella noatunensis subsp noatunensis: virulence factor characterization and vaccine development

• Published in: Applied and Environmental Microbiology
• Main Author: Lampe, Elisabeth Opsjøn
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2022
• Subjects: atlantic cod
• Online Access: http://hdl.handle.net/10852/96907

Francisella noatunensis ssp. noatunensis (F.n.n.) is a bacterium causing chronic and acute disease in the Atlantic cod industry and there is no efficient treatment or vaccine. F.n.n.-mutants lacking specific genes were constructed and they showed decreased capability to grow and cause disease in different models, like the amoebae Dictyostelium discoideum, zebrafish embryos and adult zebrafish. D. discoideum served as a suitable model for F.n.n. infection and experiments revealed that iglC is important for bacterial survival also for F.n.n. and that part of the cell degradation apparatus plays a role during F.n.n. infection. The deletion mutants, ∆iglC and ∆clpB, were tested in two different doses in adult zebrafish and the lower dose was well tolerated by the fish and stimulated a protective immune response against later exposure to a high dose of the original F.n.n. strain.