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Shigella species are generally indole negative, except for Shigella flexneri, which can be indole positive depending on the specific strain. In laboratory identification, indole testing is used to differentiate between various enteric bacteria. Therefore, while most Shigella species do not produce indole, Shigella flexneri may show positive results under certain conditions.

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5mo ago

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What test will differentiate between Salmonella enteridis and Shigella sonnei?

To differentiate between Salmonella enteritidis and Shigella sonnei, the triple sugar iron (TSI) agar test can be used. Salmonella enteritidis typically produces hydrogen sulfide (H2S), resulting in black colonies on TSI agar, while Shigella sonnei does not produce H2S and will not change the color of the agar. Additionally, biochemical tests such as urease and indole tests can further help distinguish between the two, as Shigella sonnei is urease negative and indole positive, while Salmonella enteritidis is urease negative and indole negative.


How would you determine whether a colorless colony on MacConkey agar is Salmonella or Shigella?

To differentiate a colorless colony on MacConkey agar, which indicates non-lactose fermenting bacteria, you would perform a series of biochemical tests. First, conduct a hydrogen sulfide (H2S) test; Salmonella typically produces H2S, resulting in black precipitate on triple sugar iron (TSI) agar, while Shigella does not. Additionally, you can perform an indole test; Shigella flexneri is indole positive, while Salmonella is usually negative. Confirmatory tests, such as serotyping or specific PCR assays, can further identify the organism.


What test will differentiate between Proteus vulgaris and Citrobacter freundii?

Indole test,Proteus vulgaris is be indole positive and Citrobacter freundii will be indole negative


Is staphylococcus epidermidis indole positive?

S.aureus is a positive gram. Indole test is a part the biochemistry test to determinate a bacteria negative gram. indole test used to determine S.aureus, the result is negative. That is improve which S.aureus haven't trytophanase enzym (please see indole test principle)bcb


Is shigella positive for nitrate?

yes


Indole test in vibro cholera?

The indole positive test is used to test the absence or presence of the vibro cholera.


Does proteus vulgaris produce h2s?

Yes, it does. It is Indole Production positive, H2S positive, and Motility positive. This can all be seen using SIM agar. Yes, it does. It is Indole Production positive, H2S positive, and Motility positive. This can all be seen using SIM agar.


Name one indole positive organism?

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Is Shigella Positive for a citrate test?

Based on my own test, Shigella flexneri tests negative for the citrate test.


What test will differentiate between Klebsiella pneumonia and Citrobacter freundii?

Biochemical tests such as indole test and citrate utilization can help differentiate between Klebsiella pneumoniae and Citrobacter freundii. Klebsiella pneumoniae is indole negative and citrate positive, while Citrobacter freundii is indole positive and citrate negative. Additional tests like urease and motility can also aid in differentiation.


What is Staphylococcus aureus sim test results?

Staphylococcus aureus is negative for motility, and positive for the indole production. The SIM test tests for sulfur reduction, indole production and motility. Positive for indole production means tryptophan is broken down into indole and pyruvate and will give a red color. Motility, you will see the bacteria move outside of the stab. Positive for sulfur reduction will give a black color in the medium.


Is shigella dysentery acid fast positive?

No, Shigella dysentery is not acid-fast positive. Shigella is a genus of bacteria that are Gram-negative and do not retain the stain used in acid-fast bacilli (AFB) staining. Acid-fast positivity is characteristic of mycobacteria, such as Mycobacterium tuberculosis, not Shigella. Therefore, Shigella dysentery would not be identified as acid-fast in laboratory tests.