Proteus vulgaris

Basic description of microbe:

• Straight rods

• Motile

• Facultatively anaerobic

• 0.4-0.8 μm in diameter x 1-3 μm in length

• Optimal temperature: 37 ˚C

What it looks like on the agar:

• Whole Colony***                                Round

• Margin***                                           Smooth

• Elevation                                              Growth into medium

• Color                                                   Turns agar dark yellow color

*** Colonies produce a swarming growth pattern which make it difficult to see the individual colonies.

Biochemical tests: 

• Oxidase                                                negative

• Catalase                                               positive

• Methyl red                                            positive

• Indole                                                   positive

• Voges-Proskauer                                 negative

• Simmons Citrate                                   usually negative

• Lysince Decarboxylase                         negative

• Phenylalanine Deaminase*                    positive

• Urea hydrolysis                                     positive

• H₂S                                                      positive

 *Phenylalanine Deaminase useful in differentiating Proteus, Providencia, and Morganella from other Enterobacteriaceae.

Interesting Facts:

Occur in intestines of humans and a wide variety of animals as well as in manure, soil, and polluted waters