Which bacterial species can use citrate as their only source of carbon?
Simmons citrate agar contains sodium citrate as the sole source of carbon, ammonium dihydrogen phosphate as the sole source of nitrogen, other nutrients, and the pH indicator bromthymol blue. This test is part of the IMViC tests and is helpful in differentiating the Enterobacteriaceae .
Which organism is not able to utilize citrate as a source of carbon?
Escherichia coli and Shigella dysenteriae are citrate negative.
What is the citrate utilization test used for?
Citrate utilization is a metabolic test used to determine an organism’s ability to utilize citrate as its lone source of carbon. Simmons citrate agar is a synthetic medium containing citrate, ammonium ions, and the pH indicator bromthymol blue.
How can citrate be used by microorganisms for energy?
Citrate agar is used to test an organism’s ability to utilize citrate as a source of energy. When the bacteria metabolize citrate, the ammonium salts are broken down to ammonia, which increases alkalinity. The shift in pH turns the bromthymol blue indicator in the medium from green to blue above pH 7.6.
What is the end product of citrate test?
The citrate test identifies the use of citrate as a sole carbon source, since there are no other nutrients in this medium. The basic end products (carbonates, bicarbonates, and ammonium hydroxide) will cause the brom thymol blue indicator in the medium to turn from forest green to royal blue.
What 3 products are involved in the citrate test?
Citrate utilization test is used to determine the ability of bacteria to utilize sodium citrate as its only carbon source and inorganic ammonium dihydrogen phosphate (NH4H2PO4) as the sole nitrogen source….Media Composition.
| Ingredient | Simmons Citrate Agar (g/L) |
|---|---|
| Bromothymol blue | 0.08 g |
| Distilled water | 1 L |
| Final pH | 6.9 |
What reagent do you add to Citrate test?
Bacteria are inoculated on a medium containing sodium citrate and a pH indicator such as bromothymol blue. The medium also contains inorganic ammonium salts, which are utilized as sole source of nitrogen.
Which broth is used for citrate test?
Citrate agar
Is E coli indole positive or negative?
Indole production is often used to differentiate E. coli from other indole-negative enteric bacteria because 96% of E coli are indole positive, whereas many enterobacterial species are negative in the indole reaction.
What does citrate mean?
: a salt or ester of citric acid.
What is the name of the pH indicator in a citrate agar slant quizlet?
-we can detect the use of citrate using a citrate agar slant containing sodium citrate and the pH indicator bromothymol blue.
Is blood agar Gram-positive or negative?
Phenyl Ethyl Alcohol Blood agar (PEAB): a selective medium for gram-positive bacteria that retards or completely inhibits the growth of gram-negative organisms. The addition of blood also makes it differential, similar to BAP. Specimen material is streaked on the surface of these media to yield isolated colonies.