This bright pink species was recently isolated by undergraduate student Stephanie Morgan of the Stage College of Florida for the Small World Initiative microbe hunting course. I talked to Stephanie at her poster at the 2014 ASM General Meeting (she did an excellent job!), and I had also seen some of her posts of this isolate on the Small World Initiative Facebook page.
Stephanie’s 16S rDNA data suggest this is a Vibrio species, and if you know about the Small World Initiative, you might guess that this isolate produces antimicrobials in addition to the stunning pink color, and it does! It is also important to keep in mind that in some pigment producing species, the pigment itself has antimicrobial properties. In other words, the observed color and antibiosis may be caused by the same chemical.
In the above photo, also from Stephanie Morgan’s work, the pink Vibrio isolate on the left has produced an antimicrobial compound (or several compounds) effective against many bacterial species tested, including the Staphylococcus epidermidis overlay shown here.
The isolate on the far right is also interesting. It appears this isolate has an ability to spread across the agar surface, possibility by swarming. Notice the finer structure at the leading edge of each branch.