Sorbitol MacConkey Agar , 250g

Description: 

Escherichia coli O157 is recognised as a cause of haemorrhagic colitis, an illness characterised by bloody diarrhoe a and severe abdominal pain, and haemolytic uraemic syndrome (HUS) 1, 2, 3, 4, 5 , and as such, is a significant human pathogen. 

Sorbitol MacConkey Agar is recommended for the isolation of pathogenic E. coli O157. The formulation, based on that described by Rappaport and Henig6, 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 colourless colonies. In contrast, most E. coli strains ferment sorbitol and form pink colonies. The efficiency of Sorbitol MacConkey Agar has been confirmed by March and Ratnam7. 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 screen ing for E. coli O157. 

Chapman and co-workers8 added cefixime and potassium tellurite to Sorbitol MacConkey Agar to improve the selectivity of the medium. 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. 

The use of cefixime and tellurite in Sorbitol MacConkey Agar for isolation of E. coli O157:H7 is described in the FDA Bacteriological Analytical Manual 9. 

Specification: 

250g