When my friend Steve Finkel and I get together, the talk is almost always about bacteria. He and I are both huge fans, from different angles. I’m a spectator. He studies them (E. coli) in his lab at the University of Southern California. I used to work down the hall from him, so I’m sure that some of my enthusiasm for the tiny creatures can be blamed on him, along with USC’s out-of-control microbe-lover Ken Nealson (Shewanella oneidensis is his bug, among others).