Gram Negative Rod Tests

Gram Stain Reaction of Escherichia coli

Gram stain of E. coli

McConkey's Medium


Lactose negative


Lactose positive


SIM medium

Citrate medium

Oxidase Test

Urease medium

Pseudomonas aeruginosa 
SIM (-), Oxidase (+)
Escherichia coli 
Urease (-), Citrate (-)
Proteus vulgaris 
SIM (+), Oxidase (-)
Enterobacter aerogenes 
Urease (-), Citrate (+)
Klebsiella pneumonia 
Urease (+), Citrate (+)

Refer to Table of Contents for instructions on inoculating the media

Main Page Table of Contents Gram Negatives Gram Negative Flow Chart
©1996,1997 Neal R. Chamberlain, Ph.D. and Betty Cox, M.A.. All rights reserved.