alt Hacker NewsLeptospirosis is very rare (~100 cases/year in the UK?) and typically affects other tissues (She's lucky it seems to have only infected one eye), making it more like a unicorn than a zebra diagnostically. Effective antibiotics are common, but even via IV they might reach not therapeutic levels in the eye.
Metagenomics are particularly good in cases like this where tissue samples are small. These spirochete are too small for light microscopy - probably why the lab missed them.
Given that leptospirosis is treated with doxycycline, you would have thought that they would have at least done a resistance study on the culture. Even if you don’t know it’s leptospirosis, you can know it’s susceptible to tetracyclines and treat it.