Sorbitol MacConkey Agar 90mm Plates Pk 10

Selectively detect Escherichia coli O157 with Thermo Scientific™ Oxoid™ Sorbitol MacConkey Agar. The formulation, based on that described by Rappaport and Henig¹ is identical to MacConkey Agar No.3, except that lactose has been replaced with sorbitol. E. coli O157 does not ferment sorbitol and, therefore, produces colorless colonies. In contrast, most E. coli strains ferment sorbitol and form pink colonies.

Escherichia coli O157 is a significant human pathogen and is recognised as a cause of hemorrhagic colitis, an illness characterized by bloody diarrhoea, severe abdominal pain and hemolytic uraemic syndrome. Use Sorbitol MacConkey Agar for selective detection of Escherichia coli O157.

• Sensitive and specific for E. coli O157 based on sorbitol fermentation.
• Recommended as a simple, inexpensive, rapid and reliable means of screening for E. coli O157.
• Ready-to-use convenience of prepared media.

The efficiency of Sorbitol MacConkey Agar has been confirmed by March and Ratnam². These workers reported a sensitivity of 100% and a specificity of 85%, and recommended the medium as a simple, inexpensive, rapid and reliable means of screening for E. coli O157.

The selectivity of the medium is further enhanced by the addition of cefixime and potassium tellurite. The level of potassium tellurite selects serogroup O157 from other E. coli serogroups and inhibits Providencia and Aeromonas species. Cefixime is inhibitory to Proteus spp.