TSI media contains glucos, lactose, sucrose, ferric chloride and phenol red.

Read after 24 hours

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An acid but (yellow) means glucose fermentation

An acid slant (red) means lactose or sucrose fermentation

Black indicates HS production

Bacteria that can ferment sugar at the but are generally anaerobic enterobacters.

For all lactose negative cultures (TSI test after gram negative result)

Determines if the enzyme uriase is present

Heavy innoculum should be used

if the yellow media turns red in 2-4 hours: proteus

if the yellow media turns red in 24 hours: klebsiella

Determines if a bacteria can use citrate as the sole carbon source

Check after 24 hr and after 5 days

Amonium phosphate is converted to amonium hydroxide which changes the color of bromethyl blue from green to blue.

Change to blue (+) : salmonella, arizona, citrobacter, enterobacter