Clinical Microbiology



Click on the picture for
Packaging / Colonies appearance

For overnight detection of
Gram negative bacteria producing

Typical Appearance of microrganisms

E. coli C3GR  Dark pink to reddish
Klebsiella, Enterobacter, Citrobacter   metallic blue
Proteus   brown halo
Sensitive Gram negative strains   inhibited

Order References 

Please use these references when
contacting your local distributor:
Product = base powder CHROMagar Orientation + CHROMagar C3GR Supplement

5000 mL ........... CGRT2  
   (base powder ref: RT412 + supplement ref: CG632)
25 L ............ CGRT3-25  
   (base powder ref: RT413-25 + supplement ref: CG633-25)

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


Medium Description

CHROMagar™ C3GR supplement added to CHROMagar™ Orientation contributes to the rapid screening of Gram negative C3GR-producing bacteria. 
CHROMagar™ C3GR  combines the species colour differentiation and a selectivity that allows the growth of microorganism with the reduced susceptibility to 3rd generation cephalosporins.

1. Detection after overnight incubation

2. Good species differentiation thanks to the chromogenic performances of supplemented CHROMagar™ Orientation. Indeed, the product is composed of a powder base CHROMagar™ Orientation and a supplement to enhance ESBL-producing bacteria.

3. High sensitivity: Unique medium not inhibiting plasmid-mediated AmpC-producing bacteria.

4. Time and workload savings: Direct culture from specimen. There is no need of a selective pre-enrichment.

Medium Description 

CE marked Product. 
In the USA: For Research Use Only
Please refer to our notice and Material Safety data sheet for complete information about the medium. 
CHROMagar™, Rambach™, AquaCHROM™ are trademarks created by Dr. A. Rambach.

                                                                   Last Update: 28-May-2020

Focus on C3GR

B-Lactamase production (ESBL, AmpC,...) is the most common mechanism of B-lactam drug resistance in Gram negative bacteria. Many clinical laboratories currently screen for ESBLs but do not screen for AmpC B-lactamases; though bacteria (mostly Klebsiella pneumoniaE. coli, Enterobacter and Proteus) producing plasmid-mediated AmpC B-lactamases have been responsible for nosocomial outbreaks. 

Therefore, it is crucial to ensure that proper surveillance is in place to help establish appropriate guidelines and policies for infection control. Rapid detection of bacteria producing these enzymes also allows for de-escalation to more targeted therapy, to conserve carbapenem antibiotics for more serious infections. 





Evaluation of four media for the isolation of resistant Gram negative organisms from surveillance rectal swabs


Natasha Caesar, Ricci, Richardson William Osler Health System, Brampton, CA Poster P112 ASM 2012
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