Clinical Microbiology



Click on the picture for
Packaging / Colonies appearance

For detection of 
Shiga-Toxin producing E.coli (STEC)

Most common Shiga-Toxin E.coli serotypes 
→ mauve
Other Enterobacteriacae 
→ colourless, blue or inhibited
Gram positive bacteria 
→ inhibited


Order References 

Please use these references when
contacting your local distributor:

5000 mL pack .............................................. ST162
Product = powder base ST162(B) + supplement ST162(S)

To download the certificate of analysis, please indicate your lot number below :


Medium Performance

  • Easy reading: A majority of STEC strains grow in mauve colony color, while other bacteria grow in blue, colourless or are inhibited. 
  • Highly STEC selective medium: Excellent tool for large number of samples screening procedures. 
  • Worldwide premiere: Unique medium in the market for STEC detection. 
  • Flexibility: It can be supplemented with additional compounds to render it even more selective for the strain causing an outbreak.

  • Medium Description

CHROMagar™, Rambach™, AquaCHROM™ are trademarks created by Dr. A. Rambach.
    All pictures of our products are CHROMagar property and should not be used without our acceptance.

      Last Update: 07-May-2020

Focus on STEC E.coli

An increasing and worrisome number of studies have lately shown that, non-O157 ShigaToxin-producing E.coli (STEC) have been responsible for foodborne poisoning outbreaks. The CDC has also reported warnings about this potential risk: 

“ Disease caused by Shiga toxin-producing Escherichia coli (STEC) ranges from self-limiting diarrhea to hemorrhagic colitis and hemolytic uremic syndrome (HUS). Serotype O157:H7, the most frequently implicated STEC causing hemorrhagic colitis and HUS, has been isolated from large foodborne outbreaks, as well as sporadic cases, in North America and abroad. However, 60 STEC serotypes have been implicated in diarrheal disease, and several non-O157:H7 serotypes have been implicated as the cause of foodborne outbreaks and HUS in the United States, Europe, and Australia. Studies from Canada, Europe, Argentina, and Australia suggest that non- O157:H7 STEC infections are as prevalent, or more so, than O157:H7 infection.” 

CDC report « Prevalence of Non-O157:H7 Shiga Toxin-Producing Escherichia coli in Diarrheal Stool Samples [...]» 

Therefore, several regulatory authorities urge worldwide food industry to implement measures to control the absence of such organisms in their production. 
In many cases, laboratories have limited their search for pathogenic E.coli to the common O157 serotype. This is due, among other reasons, to the fact that there were no available selective culture media for non-O157 E.coli
CHROMagar STEC is designed to fill this gap: detection, as mauve colonies, of not only the classical STEC O157, but also many other serotypes.


Comparison of Six Chromogenic Agar Media for the Isolation of a Broad Variety of Non-O157 Shigatoxin-Producing Escherichia coli (STEC) Serogroups


Bavo Verhaegen, Koen De Reu 1, Marc Heyndrickx and Lieven De Zutter

Evaluation of three ELISA or lateral flow assays and a chromogenic agar to detect shiga toxin-producing E.coli in stool


A.M Hill, MT (ASCP); K.L. Walthall, M.S; C.D. Doern, Ph D.; B.A. Forbes, Ph. D VCU Medical Center

Two-step of Shiga-toxigenic Escherichia coli (STEC) with chromogenic media (CGM) and enzyme immunoassay (EIA) from human stool samples


K.E. Tan, B. Walker, L. Hoang, P. Kibsey Island Health, Victoria, BC, Canada
more publications