What does hektoen enteric agar test for?
What does hektoen enteric 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 requirement for hektoen enteric agar preparation?
Preparation and Method of Use of Hektoen Enteric Agar Suspend 72.66 grams in 1000 ml purified/ distilled water. Heat to boiling to dissolve the medium completely.
Does hektoen enteric agar have a PH indicator?
Ferric Ammonium Citrate, a source of iron, allows the detection of hydrogen sulfide (H2S) produced from Sodium Thiosulfate. H2S-positive colonies have black centers. Bromothymol Blue is added as the pH indicator. Agar is the solidifying agent….Item No. NCM0006A.
| Formula | Liter |
|---|---|
| Acid Fuchsin | 0.1 g/L |
| Agar | 13.5 g/L |
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.
Can E coli grow on hektoen enteric agar?
Most coliforms are inhibited on Hektoen Enteric Agar, but species may overcome the inhibitory effects of the medium after prolonged incubation. Coliforms that can ferment the available carbohydrates, such as Escherichia coli, will produce orange to salmon-coloured colonies.
Is hektoen enteric agar selective?
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.
Does Vibrio grow on hektoen Agar?
Abstract. Unless laboratories use an inhibitory medium, Vibrio parahaemolyticus will be unrecognizable in fecal specimens. Eight Kanagawa-positive and two of three Kanagawa-negative strains of V. parahaemolyticus grew as well on MS as on TCBS and better than on a representative enteric medium, Hektoen enteric agar (HE) …
What is in hektoen Agar?
How is the Hektoen enteric ( he ) agar medium used?
This medium is particularly useful in the isolation of Shigella species. They formulated HE Agar medium while working at the Hektoen Institute in Chicago and became able to increase the recovery Salmonella and Shigella from clinical specimens.
When did Sylvia King invent Hektoen enteric agar?
Hektoen Enteric Agar is a selective and differential medium designed to isolate and differentiate members of the species Salmonella and Shigella from other Enterobacteriaceae. The medium was introduced in 1968 by Sylvia King and William I. Metzger.
When to use Hektoen agar for Salmonella testing?
Hektoen Enteric Agar Medium is recommended for differential and selective isolation of Salmonella and Shigella species from enteric pathological specimens in accordance to United States Pharmacopoeia. This medium is recommended by United States Pharmacopoeia, 2009 for testing the presence of Salmonella in dietary supplements.
What makes Enterics that do not ferment lactose colorless?
Those enterics that do not ferment lactose appear as colorless colonies. Hektoen-Enteric agar (HE) contains lactose, sucrose and salicin for determining sugar fermentation; bile salts to inhibit Gram-positive organisms; and ferric salts to detect H2S production.