Clinical Microbiology


CHROMagar™ MH Orientation

Click on the picture for
Packaging / Colonies appearance

Chromogenic Mueller Hinton medium

Typical Appearance of microrganisms

E. coli → dark pink to reddish
Enterococcus → turquoise blue
Klebsiella, Enterobacter, Citrobacter → metallic blue
Proteus → brown halo
Pseudomonas → cream, translucent
S. aureus → golden, opaque, small
S. saprophyticus → pink, opaque, small

Order References 

Please use these references when
contacting your local distributor:

5000 mL.......... MH482
25 L................ MH483-25

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


Medium Performance

CHROMagarTM MH Orientation is a chromogenic Mueller Hinton agar. This product was developed with the aim to speed up the time to results by combining the chromogenic differentiation of the species in the sample, and the antibiotic susceptibility test. This tool allows a same-day results in both fields, the identification and susceptibility, directly in the primary culture, contrary to the concomitant traditional protocol which takes 48 hours.

1. 2 in 1: It allows chromogenic identification and antibiotic susceptibility in the same plate. 

2. Fast Results: For many microorganisms/antibiotics, the results can be read just after overnight incubation. 

3. Easy Plate Reading: Thanks to the chromogenic reactions, diameters and/or inhibitions zones are clearly defined.


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: 20-Jul-2020


CHROMagarTM MH Orientation has been used principally in two applications, but it certainly may find usefulness in many other cases. 
The first application is on samples from ICU patients with Ventilated Associated Pneumonia (VAP), which is one of the most frequent ICU nosocomial infections with high morbidity and mortality. Shortening the period in which empirical therapy can be optimized results in better outcomes. As stated by the Spanish team, leader in this protocol2, plating respiratory samples directly onto the CHROMagarTM MH Orientation is “a rapid procedure for antimicrobial susceptibility testing (...) crucial for modifying therapeutic regimens”. 

The second application is the common Urine Tract Infections (UTI) for which physicians usually prescribe an empiric therapy. Urine samples with typical infection counts of 103-10cfu/mL can be spread directly on this plate. Pluri-microbial samples as well as monomicrobial- contaminated samples can be easily investigated by this method. In this case also as in the VAP, the same-day identification and susceptibility results can confirm the empirical therapy, or help in the decision to change it.

An evaluation was carried by AB Biodisk in 2008, comparing the performances of our CHROMagarTM MH Orientation with the traditional Mueller-Hinton formulation. This study, carried with over 20 classical antimicrobial agents, concluded that the use of our medium with E-test can provide same day results. 

Direct disk diffusion test during bacteremia: evaluation of antibiotic susceptibility results


S. Akbi, N. Ahmed, N. Aggoune, A. Zerouki University of Algiers, Algeria The First International Electronic Conference on Antibiotics, May 2021

Evaluation of direct E-test on lower respiratory tract samples using a chromogenic agar medium: a rapid procedure for antimicrobial susceptibility testing


E. Cercenado, M. Marin, R. Insa, P. Martin-Rabadan, M. Rivera, E. Bouza (Madrid, ES) 19th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) 16.05.2009 - 19.05.2009

Screening prior to prostatic biopsy - a disk diffusion based method for detection of fluoroquinolone resistant Enterobacteriaceae in rectal swabs


S. Hintze, H. Janson, O. Ekelund Clinical Microbiology, Kronoberg County, Sweden ECCMID 2018
more publications