Zebrafish embryos as an infection model for Streptococcus suis infection

Background and aim

Streptococcus suis is one of the major porcine pathogens worldwide and is considered an important zoonotic pathogen that can be transmitted from pigs to human.

Pigs and mice have successfully been used in S. suis infection models, however use of these animals comes with many practical, ethical and experimental complications. Therefore another, simpler model organism would be very welcome. Upon microinjection, S. suis is able to colonize and infect zebrafish. The zebrafish immune system is very similar to the mammalian immune system. Moreover zebrafish embryos are transparent which allows visualisation of bacteria expressing fluorescent proteins and/or the use of zebrafish mutant lines expressing fluorescent proteins in the major immune cells (macrophages, T-cells, neutrophils). All these characteristics make zebrafish embryos a perfect candidate to be used in animal infection models.
In our lab, a basal S. suis infection model using zebrafish embryos that are incubated with different bacteria has been set up but more work is still needed to investigate responses of zebrafish embryos to pathogenic and non-pathogenic bacteria.

Techniques and procedures you will get acquainted with:  

The student will participate in infection and colonization studies with the natural fish pathogen Streptococcus iniae, with S. suis and with the commensal bacteria Lactobacillus plantarum, possibly also with microbiota from other animals including pigs.
For this purpose, the student will learn more about pathology of important bacterial pathogens and will become acquainted with basal zebrafish biology and zebrafish infection techniques. Furthermore the student will perform (fluorescence) microscopy, fluorescent in-situ hybridization (FISH) to detect bacteria in zebrafish tissues, and other histologic techniques to visualise infection and zebrafish (immune) responses.