Before a microbe can cause disease it must do two things. Reach a portal of entry, which is a way into the body. Then attach with molecules called adhesins before the body sweeps it off. Tap a portal to see who uses it, then run the flush test and watch who holds on.
The body and its portalstap a marker
The attachment benchpress Flush
Still attached
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Washed away
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Result
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Pick a portal, then set the flushing force and press Flush.
Portals of entry and adhesinstap a portal to begin
Run the attachment test
Does this microbe carry its adhesin?
Flushing force at this portal—
Adhesins sit on fimbriae, pili, capsules, and wall proteins. Each one binds a specific host receptor, like a key in a lock. No attachment means no infection.