ilovegerms

The National Vaccination Information Center has page that talks a little about this. http://www.909shot.com/diseases/juvenilediabetes.htm

H2S reaction aside, the easiest way to identify and Proteus species is to just streak a plate and look at the colony morphology. The genus Proteus have very distict "swarming" growth patterns on blood agar because of its motility. It grows out in concentric rings, or may even make a film. Also, all Proteus species are urease postive. You could also try to re-innoculate the H2S media, and see if you get the same result. I find it best to do innoculations in duplicate if possible. I would lean more toward the positive side; if there wasn't sulfur reduction, there shouldn't be any black.