Getting Inside

To cause meningitis, bacteria must find a way from the bloodstream into the brain, bypassing the line of defence specifically designed to prevent this: the blood-brain barrier. A team of scientists wanted to examine this intrusion in a living model, rather than in cultured cells in a lab, so turned to transparent zebrafish. They used time-lapse microscopy to observe how Group B Streptococcus, a leading cause of bacterial meningitis in newborns, takes hold. They recorded brain blood vessels (red in the video) as the bacteria (green) formed colonies and perforated the endothelial cells that line the barrier, making a space for bacteria to sneak in. The team identified a toxin involved in damaging the blood vessels, and a gene essential for the destructive process. With this gene silenced, the brain invasion was diminished, which might point to better ways to treat or prevent meningitis.

Written by Anthony Lewis

Anthony Lewis

Writer

Ant was the web editor in the early days of BPoD, and has since worked with the UK’s top science organisations as a writer and multimedia producer. He now splits his time between freelance work and managing multimedia at The Lancet.

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• Video from work by Sumedha Ravishankar and colleagues
• School of Biological Sciences, UC San Diego, La Jolla, CA, USA
• Video originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in PLOS Biology, July 2025