MacConkey Agar w/Sorbitol (Powder)

Agar medium intended for the isolation and detection of Escherichia coli 0157 H7.|Escherichia coli serotype 0157:H7 was implicated in causing hemorrhagic colitis. Farmer and Davis noted that 95% of E. coli strains ferment sorbitol while almost all strains of E coli 0157:H7 did not ferment sorbitol They used this medium in their studies to estimate the number of sorbitol-negative E. coli present in stool specimens. Sorbitol fermenting bacteria appear as reddish-pink colonies and non-sorbitol fermenting bacteria appear as colorless or transparent colonies.||Appearance: |Light pinkish-beige, homogeneous, free-flowing powder.||pH:|7.1 ± 0.2||Microbiological Tests:|The medium was prepared according to formulation and inoculated with the organisms listed below.||Escherichia coli ATCC 25922:|Growth, pink colonies (Sorbitol positive)||Escherichia coli 0157:H7 ATCC 35510:|Growth, colorless colonies (Sorbitol negative)||Enterococcus faecalis ATCC 29212:|Inhibited (No sorbitol reaction (N/A))||Klebsiella pneumoniae ATCC 13883:|Growth, pink mucoid colonies (Sorbitol positive)||Proteus mirabilis ATCC 12453:|Colorless colonies, swarming inhibited (Sorbitol negative)||Pseudomonas aeruginosa ATCC 27853:|Growth, colorless colonies (Sorbitol negative)||Staphylcoccus aureus ATCC 25923:|Inhibited (No sorbitol reaction (N/A))||Storage and Stability: |Store the sealed bottle containing the dehydrated medium at 2-30°C. Once opened and recapped, place the container in a low humidity environment at the same storage temperature. Protect it from moisture and light. The dehydrated medium should be discarded if it is not free flowing or if the color has changed from the original light pinkish-beige color.||Final pH: 7.1 ± 0.2 at 25.0°C||Appearance: |Light pinkish-beige, homogeneous, free-flowing powder.