What does indole negative mean?

Indole Spot Reagent Result Positive reaction: The development of a blue colour within 3 minutes. Negative reaction: The development of a pink colour within 3 minutes.

What organisms are indole positive?

Indole-Positive Bacteria Bacteria that test positive for cleaving indole from tryptophan include: Aeromonas hydrophilia, Aeromonas punctata, Bacillus alvei, most Citrobacter spp., Edwardsiella spp., Escherichia coli, Flavobacterium spp., Haemophilus influenzae, most Proteus spp.

Is Enterobacter indole positive or negative?

E. coli is indole-positive; Enterobacter aerogenes is indole- negative. Glucose is the major substrate oxidized by enteric bacteria for energy production. The end products of the oxidation process vary depending on the specific enzymatic pathways in the bacteria.

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.

Is Klebsiella pneumoniae indole positive?

Abstract. Klebsiellae are an important cause of nosocomial infections. The two clinically relevant species, Klebsiella pneumoniae and Klebsiella oxytoca, are differentiated by the ability to produce indole from tryptophan, K. oxytoca being indole positive.

Is Klebsiella indole positive or negative?

1) Klebsiella species: Klebs‪iella oxytoca is indole positive whereas Klebsiella pneumoniae is indole negative.

Is Klebsiella indole positive?

Klebsiellae are an important cause of nosocomial infections. The two clinically relevant species, Klebsiella pneumoniae and Klebsiella oxytoca, are differentiated by the ability to produce indole from tryptophan, K. oxytoca being indole positive.

Is Escherichia coli Gram-negative?

Examples of Gram-negative bacteria include Escherichia coli (E coli), Salmonella, Hemophilus influenzae, as well as many bacteria that cause urinary tract infections, pneumonia, or peritonitis. Gram stain can be done within a few hours.

Is Proteus mirabilis indole positive?

Proteus mirabilis (indole negative) is the most frequent Proteus species associated with urinary tract infections, but indole-positive Proteus species like Pr. vulgaris, which are more often resistant to ampicillin, may also cause urinary tract infections. These species are often associated with an alkaline urine.

Is Pseudomonas aeruginosa indole positive or negative?

Negative
Biochemical Test and Identification of Pseudomonas aeruginosa

Is Pseudomonas aeruginosa indole positive?

Pseudomonas gives negative Voges Proskauer, indole and methyl red tests, but a positive catalase test.

Which organisms are indole positive and indole negative?

Indole positive organisms 1 Klebsiella species: Klebs‪iella oxytoca is indole positive whereas Klebsiella pneumoniae is indole negative. 2 Citrobacter species: Citrobacter koseri is indole positive where as Citrobacter freundii is indole negative 3 Proteus species: Proteus vulgaris is indole positive whereas Proteus mirabilis is indole negative

How to identify weak indole producing organisms by spot test?

a conventional tube method requiring overnight incubation, which identifies weak indole producing organisms. Spot indole test is performed by using one of the three methods mentioned below. Saturate a piece of filter paper with the reagent.

What is the difference between positive and negative indole test?

Positive: Development of a blue color within 30 seconds. Most indole positive organism turn blue within 30 seconds. Negative: No color development or slightly pink color. Spot indole test along with gram stain result and colony characteristics can assist in the rapid identification of isolates. For example

Which bacteria can degrade tryptophan into indole?

Bacteria that can degrade tryptophan into indole have tryptophanase enzyme and called “ Indole positive bacteria ”. Examples of indole positive bacteria include Aeromonas hydrophila, Bacillus alvei, Escherichia coli, Klebsiella oxytoca etc.