All of the Enterobacteriaceae will have the same results for the following few tests:
Glucose fermenters
Oxidase -
Catalase +
Convert nitrate to nitrite
Facultative anaerobes (meaning they can deal with anaerobic conditions if they have to).

There are a lot of different types of agar plates used in the microbiology lab but the three most common are sheep blood agar, chocolate, and MacConkey. MacConkey agar is selective for G- bacilli and further differentiates G- bacilli through lactose fermentation.

Lactose Fermentation Test:
On MacConkey agar, lactose fermenting bacteria will turn a bright pink color. Non lactose fermenters will be clear to white colored colonies.

G- bacilli, lactose fermenters:
E. coli, Klebsiella, Citrobacter, and Enterobacter

Methyl Red Test:
The methyl red test determines if the bacteria ferment mixed acids when given glucose. This test requires a 48+ hour incubation. Methyl red is used as an indicator and will be activated at pH 4.5 and lower.

Nerdy Note
The methyl red test goes way back the late 1800’s/early 1900’s where it was originally used to distinguish enteric pathogens growing on grain versus fecal contamination. This was important at the time because fecal contamination was an indication of an unsanitary community. Scientists determined strains growing on bovine feces had a higher hydrogen ion concentration than the strains growing on grains.

Citrate Test:
The citrate test determines if bacteria can use citrate as a carbon source, and inorganic ammonium salts as a nitrogen source. Bromthymol blue is used as the indicator.

Motility Test:
The motility test determines if the bacteria can be motile in semi-solid medium. Usually a tube is stab inoculated straight down in the tube and then incubated. The tube is checked for growth away from the inoculation area.

Lysine Iron Agar (LIA) Test:
The lysine iron agar test is similar to the TSI sugar test (see below) and is sometimes used in conjunction. The LIA test determines if bacteria can decarboxylate or deaminate lysine as well as produce H2S gas. The test is used to differentiate Enterobacteriaceae. Before inoculation, the tube is purple and oddly if the tube is purple after incubation, the bacteria are lysine decarboxylate positive. How does that work? In the media of the tube is a form of glucose, dextrose, which will be fermented by all Enterobacteriaceae. There is also the indicator bromcresol purple which will turn yellow in lower pH and purple in higher pH. The dextrose fermentation will cause the pH to lower and turn the butt of the tube yellow. If the lysine in the media is decarboxylated, it will neutralize the acid and return the tube color to purple. Here is a table with the few results to be aware of.

Condition	Tube slant/butt
Before inoculation	Purple/Purple
Lysine decarboxylate positive	Purple/Purple
Lysine deaminate positive	Red/Yellow
Lysine decarboxylate and deaminate negative	Purple/Yellow

The lysine deaminate positive tube will have a red slant due to the deamination and a yellow butt because this deamination process does not raise the pH like lysine decarboxylation does. In the case with lysine decarboxylate and deaminate negative bacteria, the slant will remain purple and the butt will turn yellow due to the dextrose fermentation assuming the bacteria ferments dextrose. H₂S production was left out of this table because it is very straightforward. If the bacteria produces H₂S there will be a blackening of the media.