Enterobacteriacea biochem tests

TSI agar tests for what sugars

Lactose sucrose and glucose

Klingler’s iron agar (KIA) alkaline slant/acid

ferments glucose but not lactose, produces small amount of acid- enough to turn both slant and but yellow. Once glucose is exhausted the org in the slant shifts to oxidative degredation and relases alkaline amines to turn the slant red (alkaline). While the but with no oxygen to support the reversal stays yellow. Non-lactose fermenters. red/yellow

KIA lactose fermenter acid/acid

ferments lactose but keeps producing acid past glucose will remain acidic. Yellow/yellow

TSI reagents

sodium thiosulfate= H2S gas

TSI red means

Alkaline. Does not ferment

TSI yellow means

Acid. Does ferment

Tryptophanase with Kovac's reagent

Indole tests for

Purple and colorless

Indole pos and neg color

Mac agar selective

inhibit gram pos with bile salts and crystal violet

Lactose fermenter

Mac agar differential

Pink and colorless

Pos and neg Mac agar color

VP

Tests if bacteria can use glucose by the butylene glycol pathway

Glucose, pyruvic acid, acetoin, KOH, alpha naphthol

Chemicals used in VP

Red and colorless

VP pos and neg reaction

tests if an organism uses citrate as its source of carbon

Citrate utilization

increase

If an organism can metabolize citrate pH will

Blue

Positive citrate turns

Urea test

tests if the organism possess the enzyme urease to hydrolyze urea to ammonia

alkaline is pink

Urea reaction positive

acidic is colorless

Urea reaction negative

oxidative fermentative test

Identifies which bacteria has the enzyme cytochrome oxidase

O+ F+/ O+ F-/O- F-

Label this OF test

Nitrate test

Tests if organism can reduce nitrate to nitrite

Add sulfanilic acid and alpha naphthylamine

Nitrate reactants

If no color change during nitrate test

No nitrite present OR N2 gas was produced

What is added to confirm a negative nitrate test

Zinc dust, pink confirms neg, no color change confirms pos