Is hektoen enteric agar defined or undefined?

Is hektoen enteric agar defined or undefined?

HE agar is a complex (chemically undefined), moderately selective, and differential medium designed to isolate Salmonella and Shigella species from other enterics.

In what two ways is hektoen enteric Agar A differential medium?

Hektoen enteric agar is a selective as well as differential media for the isolation and differentiation of enteric pathogens from clinical specimens. The presence of the bile salts and dyes inhibits most gram-positive organisms allowing only gram-negative rods to grow on HE agar.

What bacteria is hektoen agar designed to isolate?

BD Hektoen Enteric Agar is a moderately selective and differential medium for the isolation and cultivation of gram-negative enteric micro-organisms, especially for the isolation of Shigella and Salmonella species from fecal specimens.

What is the color of hektoen enteric agar?

Blue-green
Blue-green to blue in colour, most strains being black in the centre or over their entire surface. All Salmonella serotypes have this aspect on HE agar with the exception of the Typhi serotype, which is a low producer of H2S, and rare lactose-fermenting strains of Salmonella.

What does hektoen agar test for?

Hektoen enteric agar (HEK, HE or HEA) is a selective and differential agar primarily used to recover Salmonella and Shigella from patient specimens. HEA contains indicators of lactose fermentation and hydrogen sulfide production; as well as inhibitors to prevent the growth of Gram-positive bacteria.

What is the purpose of hektoen agar?

Hektoen Enteric Agar (HE) is a selective and differential medium designed to isolate and differentiate members of the species Salmonella and Shigella from other Enterobacteriaceae.

What can grow on hektoen agar?

Hektoen Enteric Agar (HE) is a selective and differential medium designed to isolate and differentiate members of the species Salmonella and Shigella from other Enterobacteriaceae. Bile salts and the dyes bromthymol blue and acid fuchsin inihibit the growth of most Gram positive organisms.

What does hektoen agar contain?

The nutritional components of Hektoen Agar include a mixture of meat peptone, yeast extract, along with the carbohydrates lactose, sucrose, and salicin. The relatively high levels of carbohydrates and peptone counteract the inhibitory effects that bile salts may have on certain organisms, such as Shigella species.

What is in Hektoen Enteric Agar?

HE agar is composed of proteose peptone, yeast extract, sodium chloride, lactose, sucrose, salicin, bromothymol blue, acid fuchsin, sodium thiosulfate, iron (III) ammonium citrate, bile salts, agar, and distilled or deionized water.

What possible results can be obtained from the Hektoen enteric test?

Result Interpretation on Hektoen Enteric Agar coli) are moderately inhibited and produce bright-orange to salmon pink colonies. Salmonella colonies are blue-green typically with black centers from hydrogen sulfide gas. Shigella appear greener than Salmonella, with the color fading to the periphery of the colony.

How do you read hektoen agar?

coli) are moderately inhibited and produce bright-orange to salmon pink colonies. Salmonella colonies are blue-green typically with black centers from hydrogen sulfide gas….Result Interpretation on Hektoen Enteric Agar.