Dichtomous chart

MAC plate (note whether or not it can ferment lactose. Pink for ferment, colorless for not.)

Alcaligenes faecalis

Pseudomonas aeruginosa (can confirm with a LDL test)

Gram Negative Bacteria

Glucose test

Produces acid and gas (no bubble)

Produces acid only (yellow)

Does not ferment (no color change)

Indole test

Iodole positive (red ring)

Iodole positive (no red ring)

Providencia alcalifaciens

Salmonella enteritidis

Citrate test

Positive (pink)

Negative (no color change)

Sucrose test

Produces acid (yellow) and gas (no bubble)

Produces neither gas nor bubbles

Escherichia coli (can confirm with a a EMB plate)

Lactose test

Produces gas and bubbles

No gas production or bubbles

Proteus vulgaris

M.R. (methyl red) test

Acid produced (red color)

Acid was not produced (stays orange)

Enterobacter aerogenes

Hydrogen sulfite test

H2S positive (black precipitate)

H2S negative (no black precipitate / no change)

Citrobacter freundii

Klebsiella pneumoniae