What is SS Agar used for?
What is SS Agar used for?
It is used as a selective and differential medium for the isolation of Salmonella and some Shigella species from clinical and non-clinical specimens. This medium is not recommended for the primary isolation of Shigella.
Which media is used for Shigella?
Commonly used primary isolation media include MacConkey, Hektoen Enteric Agar, and Salmonella-Shigella (SS) Agar. These media contain bile salts to inhibit the growth of other Gram-negative bacteria and pH indicators to differentiate lactose fermenters (Coliforms) from non-lactose fermenters such as shigellae.
Can Shigella grow on nutrient agar?
⇒ Special requirements – Shigella dysenteriae have no complex nutritional requirements and readily grow in ordinary media like Nutrient Agar medium (NAM). Commonly the MacConkey Agar medium & XLD medium is used for the cultivation of Shigella dysenteriae in the Laboratory.
Is SS Agar differential?
SS Agar is a differential, selective medium for the isolation of Shigella and Salmonella species from pathological specimens, suspected foodstuffs, etc. Gram-positive and coliform organisms are inhibited by the action of the selective inhibitory components brilliant green, bile salts, thiosulphate and citrate.
What bacteria can grow on Cetrimide Agar?
Cetrimide agar is a type of agar used for the selective isolation of the gram-negative bacterium, Pseudomonas aeruginosa. As the name suggests, it contains cetrimide, which is the selective agent against alternate microbial flora.
What are the types of Shigella?
Shigella dysenteriae
Shigella flexneriShigella sonneiShigella boydii
Shigella/Lower classifications
How do you make SS Agar?
Preparation of SS Agar
- Suspend 60 g of the medium in one liter of deionized or distilled water.
- Mix well.
- Heat with frequent agitation and boil for one minute.
- Do not autoclave the media.
- Pour into plates.
- Let the agar solidify and store in the refrigerator (avoid freezing).
Does Shigella grow on MacConkey Agar?
Shigella grows as non-lactose-fermenting colonies on MacConkey agar, although a more selective agar is used for the isolation of Shigella from feces, such as deoxycholate citrate agar and xylose lysine deoxycholate agar.
Why is SS Agar selective and differential?
Salmonella Shigella (SS) Agar is highly selective for Salmonella species, but is inhibitory to some strains of Shigella. It was developed to aid in the differentiation of lactose and non-lactose-fermenters from clinical specimens, suspected foods, and other such samples.
What makes SS agar a moderately selective media?
Principles of the Procedure SS Agar and Salmonella Shigella Agar are designated as moderately selective media based upon the degree of inhibition of gram-positive microorganisms that they inhibit due to their content of bile salts, brilliant green and citrates.
When to use SS agar for Salmonella isolation?
SS Agar (Salmonella Shigella Agar) is a differential selective media used for the isolation of Salmonella and some Shigella species from pathological specimens, suspected foodstuffs etc.
Is it safe to use SS agar for Shigella?
This medium is not recommended for the primary isolation of Shigella as some of Shigella strains may not grow on SS agar due to relatively high level of selectivity. Other less inhibitory media used for the isolation, cultivation and differentiation of gram-negative enteric microorganisms are:
How long can you keep agar culture media?
Suspend 60 g of the medium in one liter of deionized or distilled water. Mix well. Heat with frequent agitation and boil for one minute. Do not autoclave the media. Pour into plates. Let the agar solidify and store in the refrigerator (avoid freezing). Prepared culture media can be kept for at least a week in refrigeration.