Biochemical Tests Flashcards
Fermentation test
Following inoculation and incubation if any of the three broth solutions (phenol red sucrose, lactose, dextrose) turn a bright yellow, it means they are producing acids. If they also produce gases there will be a bubble at the top of the ring inverted test tube inside the broth.
H2S test
After stab inoculation and incubation, if the agar turns black that means the bacteria is producing hydrogen sulfide.
Urease test
Following inoculation and incubation of the broth turns bright pink it is positive for producing urease
Citrate test
After inoculation and incubation if the slant is a deep royal blue it’s positive for citrate. Determines bacterias ability to use carbon.
Indole test
Same tube used for H2S. After inoculation and Incubation and checking the results of H2S, you would add a couple of drops of kovacs reagent. If a cherry red color is produced in the reagent layer, your unknown bacteria is positive for indole. Determines if bacteria can degrade amino acid tryptophan.
Starch hydrolysis
After inoculation, making a line in the agar and incubation. You would pour iodine on the plate, completely flooding it. It sits for a minute. If your unknown bacteria has the ability to hydro lie starch a clear area (halo) appears around the bacteria.
Catalase test
Following inoculation and incubation, you would add a couple drops of hydrogen peroxide to your tube. If bubbles form upon adding hydrogen peroxide, your unknown bacteria is positive for production of catalase.
H2S uses what tube
SIM agar deep tube
Urease test uses
Urea broth
Citrate uses
Citrate agar slant
Indole test
SIM agar deep tube
Starch hydrolysis uses
Starch agar plate
Catalase uses
TSA slant
