Tiếng Việt
- Pre-poured media on 90mm Petri dishes are used for culturing and isolating infectious agents from fecal, blood, and food specimens.
PURPOSE
TraceMedia™ MacConkey Agar/ Salmonella Shigella Agar:
- MacConkey (MC): A selective culture medium used for isolating Gram-negative bacteria that can ferment lactose. It differentiates the lactose fermentation ability of microorganisms.
- Salmonella Shigella Agar (SS): A selective and differential culture medium used for isolating and distinguishing Salmonella and Shigella.
PRINCIPLE
TraceMedia™ MacConkey Agar/ Salmonella Shigella Agar:
- MacConkey (MC): MacConkey is used for the selective culture of Gram-negative bacteria, especially for enteric bacteria and the Pseudomonas genus. The medium inhibits the growth of Gram-positive bacteria and some Gram-negative bacteria due to the presence of crystal violet and bile salts. Bacteria that ferment lactose produce acid, leading to a decrease in pH and a color change to pink or red. Additionally, acid production after lactose fermentation reacts with the bile salts to form precipitates, resulting in a bright pink zone around the lactose-fermenting colonies. Bacteria that do not ferment lactose will retain their original color, and the colonies will not be surrounded by a pink zone.
- Salmonella Shigella Agar (SS): The medium contains bile salts, sodium citrate, and brilliant green, which inhibit coliforms, Gram-positive bacteria, and Proteus, allowing only Salmonella to grow. Lactose-negative bacteria will not produce color on the medium. Lactose-positive bacteria will appear pink to red. Bacteria that produce hydrogen sulfide (H2S) will have black centers.
READING RESULTS
- After incubating for the required time, usually 16-24 hours, observe the growth of colonies on the surface of the agar plate.
- Further identification of the isolated bacteria should be conducted through appropriate tests.
