J Neuroinflammation. 2016 Aug 19;13(1):188. doi: 10.1186/s12974-016-0655-y.

Infection of zebrafish embryos with live fluorescent Streptococcus pneumoniae as a real-time pneumococcal meningitis model.

Jim KK1,2, Engelen-Lee J2, van der Sar AM1, Bitter W1, Brouwer MC2, van der Ende A3,4, Veening JW5, van de Beek D2, Vandenbroucke-Grauls CM6,7.

Author information

Abstract

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.

KEYWORDS:

Host-microbe interaction; Live cell imaging; Pneumococcal meningitis; Pneumolysin; Streptococcus pneumoniae; Zebrafish

PMID: 27542968 PMCID: PMC4992281 DOI: 10.1186/s12974-016-0655-y

[PubMed - in process]