| Characteristics Salmonella Typhi | Capsule Negative (-ve) | Catalase Positive (+ve) | Citrate Negative (-ve) | Flagella Positive (+ve) |
|---|
Is Salmonella typhi citrate positive?
When Simmons Citrate agar is inoculated with Salmonella typhimurium , the medium turns royal blue. This is
a positive result for the citrate
test. When Simmons Citrate agar is inoculated with Escherichia coli , the medium remains green. This is a negative result for the citrate test.
What bacteria test positive for citrate?
Klebsiella pneumoniae and Proteus mirabilis
are examples of citrate positive organisms. Escherichia coli and Shigella dysenteriae are citrate negative.
What does a positive citrate test indicate?
A positive reaction shows
that the organism can use citrate but not necessarily as the sole carbon source
.
Is Salmonella urease negative?
Salmonellae are also unable to deaminate tryptophan or phenylalanine and are usually
urease and indole negative
. Based on the biochemical tests above, Salmonella can presumptively be identified.
Is Serratia marcescens citrate positive or negative?
Serratia marcescens is an opportunistic,
gram negative
, nosocomial pathogen which belongs to family, Enterobacteriaceae.
How do you identify salmonella?
Salmonella species are found in faeces, blood, bile, urine, food and feed and environmental materials. The type species is Salmonella enterica. Isolates are identified by
a combination of colonial appearance, serology (agglutination with specific antisera) and biochemical testing
.
What is citrate test used for?
The citrate test
detects the ability of an organism to use citrate as the sole source of carbon and energy
.
Is Staphylococcus aureus citrate positive or negative?
| Basic Characteristics Properties (Staphylococcus aureus) | Citrate Positive (+ve) | Coagulase Positive (+ve) | Gas Negative (-ve) | Gelatin Hydrolysis Positive (+ve) |
|---|
Is E coli indole positive?
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.
Does E coli utilize citrate?
It is well known that wild-type E. coli cannot use citrate as a carbon source, aerobically, because it lacks a citrate transporter, but
can use citrate under anaerobic conditions
via expression of the CitT citrate/succinate antiporter (5,–9).
Which broth is used for citrate test?
Principle of
Simmons Citrate Agar
Simmons Citrate agar is used to test an organism’s ability to utilize citrate as a source of energy. Ammonium Dihydrogen Phosphate is the sole source of nitrogen.
Does E coli test positive methyl red?
When methyl red is added to MR-VP broth that has been inoculated with Escherichia coli , it stays red
. This is a positive result for the MR test. When methyl red is added to MR-VP broth that has been inoculated with Enterobacter cloacae , it turns yellow.
What does a negative urease test look like?
The urease produced by H. pylori hydrolyzes urea to ammonia, which raises the pH of the medium, and changes the color of the specimen from
yellow
(NEGATIVE) to red (POSITIVE).
What does a negative urease test mean?
Rapid urease tests are fast, inexpensive, and easy to perform. A limitation is that this method requires a high density of bacteria in the specimen. Negative results could mean that
the level of bacteria in the specimen obtained is low
.
What is rapid urease test positive?
Rapid urease test, also known as the CLO test (Campylobacter-like organism test), is a rapid diagnostic test for
diagnosis of Helicobacter pylori
. The basis of the test is the ability of H. pylori to secrete the urease enzyme, which catalyzes the conversion of urea to ammonia and carbon dioxide.
