Clinical Microbiology



Click on the picture for
Packaging / Colonies appearance

For overnight detection of
Gram-negative bacteria producing
Extended Spectrum Beta-Lactamase.

Typical Appearance of microrganisms

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

Order References 

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

5000 mL ........... ESRT2
(base powder ref: RT412 + supplement ref: ES372)
25 L ............ ESRT3-25
(base powder ref: RT413-25 + supplement ref: ES373-25)

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


Medium Performance

CHROMagar™ ESBL supplement added to CHROMagar™ Orientation contributes to the rapid screening of Gram-negative ESBL-producing bacteria.
CHROMagar™ ESBL supplement allows the detection of ESBL-producing bacteria while inhibiting the growth of other bacteria, including most of those carrying ampC type resistance. This is an important feature because intrinsic ampC resistance has less epidemic relevance, but often leads to ESBL false positive reading in the classical testing methods.

Detection of resistant isolates is difficult based on routine susceptibility testing performed by a clinical microbiology laboratory, while with CHROMagar ESBL supplement:

  1. Detection after overnight incubation of Gram-negative bacteria expressing a reduced susceptibility to antibiotics of the C3G family.

  2. Good species identification 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 (98 %) and Specificity (97 %)
    according to this study: "Detection of Extended-spectrum Beta Lactamase producing Enterobacteriaceae" G. Klysova and al. ECCMID 2016 Poster available at the bottom of the page.

  4. Time and workload savings: there is no need of a selective pre-enrichment.

  5. Flexibility: CHROMagar™ ESBL supplement is supplied in powder form with a shelf-life of more than 18 months. This allows for flexibility of use, whether in an epidemic situation with many patients to screen, or whether for random surveillance of cultures.

Medium Description

Gain flexibility using powder rather than ready to use plates: Use the entire pack, or if there is a need for a smaller number of plates, just a portion. If kept under appropriate storage temperature, CHROMagar Orientation and CHROMagar ESBL supplement have a more than 18 months shelf of life. This flexibility is essential to avoid the waste resulting from expired-unused plates.

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: 27-ay-2020

Focus on ESBL Resistance

ESBL (Extended Spectrum β-Lactamases) are enzymes that mediate resistance to penicillins, extended-spectrum third generation cephalosporins (C3G) and monobactams.
ESBL-producing Enterobacteriaceae started to appear in the 1980s, and have since emerged as some of the most significant hospital-acquired infections with Escherichia coli and Klebsiella sp. being the main actors but other Gram-negative species have also been observed.

ESBL Resistance Epidemiologic Issues

Emergence of ESBL-producing isolates has important clinical and therapeutic implications:

  • resistance determinants for ESBL production are carried on plasmids that can be easily spread from organism to organism.
  • the spread of resistance toward extended-spectrum cephalosporins may lead to increased prescription of more broad-spectrum and expensive drugs.
  • these resistant isolates may escape detection with routine susceptibility testing performed by a clinical microbiology laboratory, which can result in adverse therapeutic outcomes.
Therefore, the early detection of ESBL-producing bacteria carriers is important to minimise their impact and the spread of infections and customise therapeutic patient treatment.

Evaluation of three selective chromogenic media, CHROMagar ESBL, CHROMagar CTX-M and CHROMagar KPC, for the detection of Klebsiella pneumoniae producing OXA-48 carbapenemase


Michael Hornsey, Lynette Phee, Neil Woodford, Jane Turton, Daniele Meunier,Claire Thomas, David W Wareham

Comparison of three selective media for the recovery of Extended Spectrum β-Lactamase (ESBL)-producing Enterobacteriaceae


M. Jones, A. Sweeney, E. Stoeppler, M. Miller, and P. Gilligan Clinical Microbiology-Immunology Laboratories UNC Hospitals 2011

Evaluation of a chromogenic medium for extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae


Philippe Lagacé-Wiens et al. University of Manitoba, Canada. ECCMID Poster 2010
more publications