Which organism produces indole?

many pathogenic bacteria such as Bacillus alvei, pathogenic E. coli, several Shigella strains, Enterococcus faecalis, and V. cholerae, can produce indole.

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.

What is the positive result for the indole test?

A positive indole test is indicated by the formation of a red color in the reagent layer on top of the agar deep within seconds of adding the reagent. If a culture is indole negative, the reagent layer will remain yellow or be slightly cloudy.

Is Pseudomonas indole-positive?

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

Is Proteus vulgaris indole-positive?

The indole-positive members of the Proteeae, including Proteus vulgaris, Providencia spp., and M. morganii, typically are resistant to ampicillin and cefazolin, as is the indole-negative species Proteus penneri.

Is Salmonella indole-positive?

In contrast to E. coli, Salmonella does not produce indole because it does not harbor tnaA, which encodes the enzyme responsible for tryptophan metabolism.

Is Proteus vulgaris indole positive?

Is Klebsiella pneumoniae indole-positive?

K. pneumoniae is lactose fermenting, H2S- and indole-negative, has a positive Voges-Proskauer (VP) reaction, is capable of growth in KCN and using citrate as a sole carbon source, and is incapable of growth at 10ºC.

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 Salmonella indole positive?