I’ve somehow made it through 5 stories without talking about one of the most famous pathological agents… bacteria.  It’s time.

Bacteria1 are incredibly different from us.  We are more closely related to dinosaurs, roses, mushrooms, and even slime molds than we are to bacteria!

A greatly pruned version of the tree of life - bacteria branch off from most other forms of life very early.

A greatly pruned version of the tree of life. Bacteria branch off from most other forms of life very early.

There are plenty of good bacteria – they make yogurt or break down our trash– but the most famous are the bad ones.  They have names like E. coli, Staph, and Strep, and we don’t particularly enjoy their presence.  Generally, when bacteria invade, the invaded part gets warm, swollen, and tender (though there are many exceptions).  Let’s learn more by looking at one particular kind of invasion: a urinary tract infection (UTI).

  1. Bacteria is plural, bacterium is singular (because it’s a Latin neuter noun).  Now you can sound like a nerd. []