From Google’s Venture Arm Leads $51.7M Investment in Spero Therapeutics:

E. coli in petri dish
E. coli in petri dish

Photo of E. coli bacteria on petri plate selective for gram negative bacteria by Flickr user Anthony D’Onofrio
E. coli on a Petri Plate
via a Creative Commons license
https://creativecommons.org/licenses/by/2.0/