For overnight detection of beta-lactamase producing Enterobacteria achieving third generation cephalosporin resistance

Order References

Please use these references when
contacting your local distributor :

5000 mL Pack ………..CGRT2

Included : base RT412 + supplement CG632

25 L Pack ………….. CGRT3-25

Included : base RT413-25 + supplement CG633-25


Colonies Appearance

C3GR ecoli

E. coli

dark pink to reddish

C3GR klebsiella

Klebsiella, Enterobacter, Citrobacter

metallic blue (+/- red halo)

C3GR proteus


brown halo

C3GR pseudomonas


cream, opaque

C3GR acinetobacter


translucent cream to blue


β-Lactamase production (ESBL, AmpC, carbapenemase) is the most common mechanism of β-lactam drug resistance in Gram negative bacteria. Each of the involved mechanisms can be plasmid-encoded and transfer horizontally. Moreover, plasmids continuously gather other antibiotic resistance determinants, ultimately closing to pan-resistance. Their spread leads to increased colonization pressure in hospital and community as well. It is crucial to ensure that proper surveillance is in place to help implement appropriate guidelines and policies for their spread 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.

Intended Use :

CHROMagar™ C3GR is a selective and differential chromogenic culture medium, intended for use in the qualitative direct detection of gastrointestinal colonization with 3rd generation cephalosporin-resistant Enterobacteria (C3GR-E) to aid in the prevention and control of C3GR-E in healthcare settings. The test is performed with rectal swab and stools from patients to screen for C3GR-E colonization. Results can be interpreted after 18-24 h of aerobic incubation at 35-37 °C.

The medium can also be used as an early warning indicator for diagnostic tests of infections to signal the possible presence of multi drug-resistant bacteria. This use does not replace the institution’s protocols. CHROMagar™ C3GR is not intended to diagnose C3GR-E infection nor to guide nor monitor treatment for infections. A lack of growth or the absence of colonies on CHROMagar™ C3GR does not preclude the presence of C3GR-E. Further identification, susceptibility testing, and epidemiological typing is needed on suspect colonies.

1. Fast results: Detection after overnight incubation.

2. 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 select B-Lactamase 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.


Technical Documents

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Scientific Publications