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Updated: Mar 16, 2026
A Zebrafish Embryo Model for In Vivo Visualization and Intravital Analysis of Biomaterial-associated Staphylococcus aureus Infection
Published on: January 7, 2019
Infection of zebrafish embryos with live fluorescent Streptococcus pneumoniae as a real-time pneumococcal meningitis
Kin Ki Jim1,2, JooYeon Engelen-Lee2, Astrid M van der Sar1
1Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands.
Background:
Streptococcus pneumoniae is one of the most important causes of bacterial meningitis, an infection where unfavourable outcome is driven by bacterial and host-derived toxins. In this study, we developed and characterized a pneumococcal meningitis model in zebrafish embryos that allows for real-time investigation of early host-microbe interaction.
Methods:
Zebrafish embryos were infected in the caudal vein or hindbrain ventricle with green fluorescent wild-type S. pneumoniae D39 or a pneumolysin-deficient mutant. The kdrl:mCherry transgenic zebrafish line was used to visualize the blood vessels, whereas phagocytic cells were visualized by staining with far red anti-L-plastin or in mpx:GFP/mpeg1:mCherry zebrafish, that have green fluorescent neutrophils and red fluorescent macrophages. Imaging was performed by fluorescence confocal and time-lapse microscopy.
Results:
After infection by caudal vein, we saw focal clogging of the pneumococci in the blood vessels and migration of bacteria through the blood-brain barrier into the subarachnoid space and brain tissue. Infection with pneumolysin-deficient S. pneumoniae in the hindbrain ventricle showed attenuated growth and migration through the brain as compared to the wild-type strain. Time-lapse and confocal imaging revealed that the initial innate immune response to S. pneumoniae in the subarachnoid space mainly consisted of neutrophils and that pneumolysin-mediated cytolytic activity caused a marked reduction of phagocytes.
Conclusions:
This new meningitis model permits detailed analysis and visualization of host-microbe interaction in pneumococcal meningitis in real time and is a very promising tool to further our insights in the pathogenesis of pneumococcal meningitis.
Insights
This study introduces a new zebrafish embryo model for pneumococcal meningitis, enabling real-time visualization of host-microbe interactions and the role of pneumolysin in immune cell evasion.
Area of Science:
- Microbiology
- Immunology
- Zebrafish models
Background:
- Streptococcus pneumoniae is a leading cause of bacterial meningitis.
- Unfavorable outcomes are linked to bacterial and host toxins.
- A novel zebrafish embryo model was developed to study early host-microbe interactions.
Purpose of the Study:
- To develop and characterize a zebrafish embryo model for pneumococcal meningitis.
- To visualize host-microbe interactions in real-time.
- To investigate the role of pneumolysin in the pathogenesis of pneumococcal meningitis.
Main Methods:
- Zebrafish embryos were infected with wild-type or pneumolysin-deficient S. pneumoniae.
- Transgenic zebrafish lines were used to visualize blood vessels and immune cells (neutrophils and macrophages).
- Fluorescence confocal and time-lapse microscopy were employed for imaging.
Main Results:
- Pneumococci were observed to clog blood vessels and cross the blood-brain barrier.
- Pneumolysin-deficient S. pneumoniae showed attenuated growth and brain migration.
- Neutrophils were the primary immune cells responding initially, but pneumolysin reduced phagocyte numbers.
Conclusions:
- The developed zebrafish model allows for detailed, real-time analysis of host-microbe interactions in pneumococcal meningitis.
- This model is a promising tool for advancing understanding of pneumococcal meningitis pathogenesis.
- The study highlights pneumolysin's role in evading the innate immune response.
