Infectious disease studies in zebrafish : the fish pathogen Edwardsiella tarda as a model system

Abstract

In a world where bacterial infections are becoming harder and harder to fight due to rising antibiotic resistance, disease models that allow high throughput screening are needed more than ever. An ideal model organism for high throughput screening is the zebrafish embryo. However, models for high throughput screening of infection are still wanted. In this thesis the fish pathogen Edwardsiella tarda was tested for use in high throughput studies of infectious disease in zebrafish. First the genome of Edwardsiella tarda was sequenced to determine the virulence factors of this bacterium. Next different types of exposure of zebrafish to Edwardsiella tarda were tested. This showed an absence of detectable infection after static immersion, but a reproducible infection on the level of single embryos after caudal vein injection. Finally, using the caudal vein injection method, the zebrafish knock-out mutant in the gene Myd88 was characterized. This is the first zebrafish knock-out mutant in a gene central in the innate immune system.