5.4

I think I take with me the microbes you've left on my skin. I'll have the memory of every person I've ever met, unless--my biome too strong, no purchase remains. There are those whose bacterial signature is thunderous loud in the microbial world. There are those who listen. Which am I?
I shake your hand anyway, not knowing if you'll house my flora, or perhaps you'll spread to me. Either way, someone is leaving here changed.