Mystery Solved

Those of you who have been following the mystery microbe story lately will be happy to know I've solved it. My streak plate separated Serratia marscescens from the second, whitish unknown; I isolated a colony and grew another plate, then transferred a sample to an agar slant; 18-24 hours later (23, actually) I fixed a sample to a slide and gram-stained it. It turned out gram negative, narrowing down the field. A quick look at the slide on the microscope (1000x, oil immersion lens) shows individual bacilli - no chains, no clusters.

Bottom line: Escherichia coli. No doubt about it. Now to write up the term paper and collect my easy 30/30 points.

In other news, pulled a 49/50 on my last microbiology lecture exam. Stupid restriction enzyme question...