Chromogenic

Chromogenic Pre Poured Petri Dishes

E&O manufacture and stock a comprehensive range of high quality standard and bespoke formulations of readytouse plated culture media in several different petridish sizes and media depths to accommodate all microbial growth requirements. Packaging formats comply with all industry sector regulations.

View Our Chromogenic Pre Poured Petri Dishes Listcatalog-icon

  • CHROMagar™ Candida Plus is the first chromogenic isolation medium for the detection and differentiation of C. auris in addition to other major clinical Candida spp. such as C. albicans, C. tropicalis, C. glabrata. Candida spp. are yeasts involved in various infections called Candidiasis. These infections can be severe with significant morbidity in nosocomial infections or in immunocompromised patients. Although C. albicans is still the main species involved, the use of antifungal agents has given rise to other species such as C. tropicalis, C. krusei and C. glabrata. In 2016, WHO added C. auris to this list with over 90 % of strains resistant to fluconazole. CHROMagar™ Candida Plus allows for the recognition of minor candida species in a mixed population containing the predominant species, thereby allowing patient specific treatment plans to be formulated at the earliest possible opportunity. Most bacterial species will be inhibited due to the inclusion of the selective mix: C. albicans Green colonies C. tropicalis Metallic blue colonies C. glabrata Mauve to pink colonies C. auris Light blue colonies with blue halo E. coli Inhibited Limitations The final identification must be confirmed by biochemical tests or by mass spectrophotometry (eg MALDI-TOF). These can be done directly from the suspicious colonies observed on the medium.
  • Colorex 0157 with Cefixime & Tellurite This medium replaces the conventional Sorbitol MacConkey Agar that is reputed for high levels of false positives and the difficulty of colonial interpretation and differentiation. Colorex O157 is a chromogenic medium with a very high specificity (98% according to K.A. Bettelheim, 1998 J.Appl.Microbiol.85:425-428) for E.coli O157. To reduce the level of background flora, the medium is made selective by the addition of Cefixime and Potassium tellurite. Positive colonies exhibit a mauve colouration enabling easy interpretation amongst blue or colourless colonies of other bacteria.
  • Side One: Colorex mSuperCARBA™ Colorex mSuperCARBA™ is a selective chromogenic medium that has been developed for the detection and isolation of carbapenemase producing Enterobacteriaceae (CPE). Nosocomial infections due to CPE are particularly difficult due to the limited treatment options. Therefore, this medium is designed to simplify the detection of CPE carriers and to allow for improved monitoring of high risk patient groups. The distinctive colonial colouration of the various species can reduce the need for additional follow up testing allowing many positive results to be issued within 24 hours of receipt of the sample. All presumptive positive colonies should be confirmed for carbapenemase production. Typical colour reactions are as follows – Escherichia coli – Red/Pink colonies Klebsiella spp., Enterobacter spp., & Citrobacter spp. – Metallic blue colonies Other CP Gram –ve bacterial species (including Pseudomonas / Acinetobacter) – Colourless colonies Non-CPE Gram-ve bacterial species - Inhibited Gram +ve bacterial species & yeasts – Inhibited Side Two: Colorex C3GR (Opaque) Colorex C3GR is a chromogenic screening medium for the detection of β-Lactamase producing Gram-negative bacteria in clinical specimens. The selectivity of the medium allows for detection of ESBL and/or AmpC producing isolates that exhibit a reduced susceptibility to 3rd generation cephalosporin antibiotics. The chromogenic reactions allow for species differentiation on presumptive positive isolates. Typical colour reactions are as follows – C3GR E.coli – Red colonies C3GR Klebsiella / Enterobacter / Citrobacter – Metallic blue colonies C3GR Proteus – Colonies with brown halo Other C3GR Gram –ve bacterial species (Pseudomonas / Acinetobacter) – Colourless colonies C3G Sensitive Gram –ve bacterial species - Inhibited Gram + bacterial species - Inhibited Yeasts - Inhibited
  • PP3038

    Colorex STEC

    COLOREX™ STEC is a chromogenic medium(1) for the detection of enterohaemorrhagic E. coli (including serotypes O26, O111 & O157). Over the past few years there has been an increase in the number of food poisoning outbreaks where non-O157 Shiga toxin producing E. coli (STEC) have been shown to be etiological agent. The medium contains several selective agents to reduce the level of background flora from the specimen or food sample. Positive STEC colonies exhibit a mauve colouration enabling easy interpretation amongst other Gram negative bacteria that will exhibit blue or colourless colonies, if they are able to grow on the medium. Gram positive bacteria will be inhibited.
  • Colorex™Acinetobacter MDR is a chromogenic medium for the detection of multi-drug resistant (MDR) Acinetobacter spp. Positive colonies exhibit a distinct red colouration with a pale grey centre enabling easy interpretation amongst blue, violet or colourless colonies that may be produced by other Gram –ve bacteria. Gram +ve bacteria and yeast are inhibited on this medium. Limitations: 1.  Some Pseudomonas, Stenotrophomonas and Burkholderia spp. may form pale red colonies on this medium but are readily distinguishable due to differences in colonial morphology compared to the Acinetobacter spp. An oxidase test will readily differentiate any Pseudomonas spp. 2. Some Enterobacteriaceae isolates may form blue colonies on this medium. 3. Definitive MDR characterisation may require additional antibiotic susceptibility testing.
  • Chromogenic medium for detection of Clostridium difficile. Clostridium difficile (C.difficile) is the leading cause of nosocomial infectious diarrheoa in adults. These infections occur mostly in patients who have both medical care and antibiotic treatment and have become more frequent and more difficult to treat in the last years due to the emergence of highly toxigenic C.difficile strains. Although PCR has become the leading C.difficile detection technique, culture is essential for strain typing and antimicrobial susceptibility testing. CHROMagarTM C.difficile is a new fluorogenic culture medium, extremely sensitive and selective, especially designed to simplify and speed up (24h) the culture of C.difficile.
  • Colorex C3GR is a chromogenic screening medium for the detection of β-Lactamase producing Gram-negative bacteria in clinical specimens. The selectivity of the medium allows for detection of ESBL and/or AmpC producing isolates that exhibit a reduced susceptibility to 3rd generation cephalosporin antibiotics. The chromogenic reactions allow for species differentiation on presumptive positive isolates.  
  • Colorex™ Campylobacter is a chromogenic media for the isolation and presumptive identification of Campylobacter spp, from clinical specimens and food samples. Any presumptive Campylobacter colonies will produce a red colouration whilst most other organisms will be inhibited. Typical colour reactions are as follows – Campylobacter jejuni – Red colonies; Campylobacter coli – Red colonies; Campylobacter lari – Red colonies; Other Gram –ve bacteria – Blue colonies or inhibited; Gram +ve bacteria & yeasts – Inhibited. Presumptive positive Campylobacter colonies must be confirmed using serological and biochemical techniques according to the method / procedure being followed.
  • In recent years there has been an increase in the number of immuno-compromised patients, which has in turn led to an increased rate of infections associated with Candida species. There were 2151 reported cases of candidaemia in 2016 with C.albicans accounting for 42%, C.glabrata for 25%, C.parapsilosis for 9% and C.tropicalis for 3% of infections in England, Wales and Northern Ireland.(1) COLOREX™ Candida was formulated specifically for the detection and isolation of clinically significant Candida spp. by means of colonial colour and morphology within 48hrs. COLOREX™ Candida allows for the recognition of a minor Candida population within a mixed population as well as the pre-dominant species thereby allowing for a patient specific treatment plan at the earliest possible opportunity. Most bacterial species will be inhibited due to the inclusion of chloramphenicol. C.albicans – Green colonies C.tropicalis – Metallic blue colonies C.glabrata – Mauve to pink colonies C.krusei – Large fuzzy pink colonies Limitations Definitive identification requires additional testing of isolates (e.g. MALDI-TOF). C.glabrata and C.parapsilosis cannot be readily distinguished on this particular medium. C.dubliniensis will form dark green colonies on COLOREX™ Candida so additional testing is required to confirm presence in the specimen. C.auris isolates will grow on this medium but the colony colour may vary from white to pale purple/pink so further testing will be required to confirm identification.
  • Recent developments in culture media have given rise to the use of chromogenic substrates as a means of differentiating bacteria particularly among the Enterobacteriaceae. Colorex™ ESBL (Extended Spectrum Beta-Lactamase) medium has been developed for the isolation of ESBL – producing organisms with the aim of simplifying the differentiation and presumptive identification of the causative organism. It should be noted that other non-ESBL and AmpC isolates will be inhibited on this medium reducing the incidence of false positives. The distinctive colonial colouration of the various species can reduce the need for additional follow up testing allowing many positive results to be issued within 24 hours of receipt of the sample. If necessary an Indole test for confirmation of Escherichia coli and TDA test for Proteus spp. can be performed directly from the medium. Typical colour reactions are as follows: Escherichia coli – Red colonies; Proteus spp., Providencia spp. & Morganella spp. – Clear colonies with a brown halo; Klebsiella spp., Enterobacter spp, Serratia spp. & Citrobacter spp. – Metallic blue colonies; Salmonella spp. & Acinetobacter spp. – Clear colonies; Gram +ve bacterial species and yeasts – Inhibited.
  • Recent developments in culture media have given rise to the use of chromogenic substrates as a means of differentiating bacteria. This is one such medium and is a selective medium for the isolation and presumptive identification of Listeria monocytogenes from clinical and food samples. The medium is made selective by the inclusion of Lithium chloride, Ceftazidime, Polymixin B, Nalidixic acid (to suppress other bacteria) and Amphotericin B (to suppress yeasts and fungi). With the combination of both the chromogenic substrate and phospholipase C enzyme reactions, it is possible to differentiate L.monocytogenes from other Listeria spp. Users should be aware that some strains of L.ivanovii are capable of producing an opaque halo, highlighting the need to confirm presumptively identified colonies.
  • This is a selective chromogenic medium for the detection of Malassezia spp., especially M.restricta and M.globosa, in veterinary or clinical specimens. Malassezia spp. is a commensal organism in humans and animals that can cause severe dermatitis or otitis infections. The medium is supplemented with Glycerol and Tween 40 to enhance the in-vitro growth of Malassezia spp. due to the complex lipid requirements of these yeasts. Appearance and differentiation of Malassezia spp. is readily apparent by the distinctive colonial colours allowing for differentiation from Candida spp. in specimens. The inclusion of chloramphenicol ensures the inhibition of bacterial species during incubation of specimens.
  • Colorex™ MRSA is a chromogenic medium for the selective isolation of Methicillin-Resistant Staphylococcus aureus (MRSA). The medium can be used for the routine screening of clinical specimens for MRSA from a variety of sampling sites such as the nose, throat and groin. The medium incorporates a nutritious peptone base medium and a number of selective agents to inhibit most Gram-negative and Gram-positive bacteria as well as yeasts and moulds. The chromogenic detection of specific enzyme activity leads to the formation of pink/mauve colonies indicating MRSA (including low level resistant and hetero-resistant strains) following incubation at 37°C for 18-24 hours. Other organisms, if present are indicated by blue or colourless colonies. Any presumptive isolates must be confirmed using serological and/or biochemical techniques available to the laboratory. The use of this chromogenic medium does not diminish the requirement for conventional antimicrobial susceptibility tests for the confirmation of methicillin resistance. Limitations: 1. S.aureus strains that possess a low MIC to the selective agent present in the medium but are mec A negative may form colonies on the medium. 2. Some MRSA strains may form typical colonies surrounded by a matte halo. The formation of the halo serves no diagnostic function. 3. Certain methicillin-resistant coagulase-negative staphylococci (CNS) may produce characteristic colonies. In some cases differentiation may be achieved by examination of the colour of these colonies, as they may be considerably darker in colour (bluish purple to a very dark pink/magenta). 4. Certain bacterial species other than staphylococci may produce colonies with a characteristic colour.
  • Colorex™ MRSA is a chromogenic medium for the selective isolation of Methicillin-Resistant Staphylococcus aureus (MRSA). The medium can be used for the routine screening of clinical specimens for MRSA from a variety of sampling sites such as the nose, throat and groin. The medium incorporates a nutritious peptone base medium and a number of selective agents to inhibit most Gram-negative and Gram-positive bacteria as well as yeasts and moulds. The chromogenic detection of specific enzyme activity leads to the formation of pink/mauve colonies indicating MRSA (including low level resistant and hetero-resistant strains) following incubation at 37°C for 18-24 hours. Other organisms, if present are indicated by blue or colourless colonies. Any presumptive isolates must be confirmed using serological and/or biochemical techniques available to the laboratory. The use of this chromogenic medium does not diminish the requirement for conventional antimicrobial susceptibility tests for the confirmation of methicillin resistance. Limitations: 1.  S.aureus strains that possess a low MIC to the selective agent present in the medium but are mec A negative may form colonies on the medium. 2. Some MRSA strains may form typical colonies surrounded by a matte halo. The formation of the halo serves no diagnostic function. 3. Certain methicillin-resistant coagulase-negative staphylococci (CNS) may produce characteristic colonies. In some cases differentiation may be achieved by examination of the colour of these colonies, as they may be considerably darker in colour (bluish purple to a very dark pink/magenta). 4. Certain bacterial species other than staphylococci may produce colonies with a characteristic colour.
  • Colorex™ mSuperCARBA™ is a selective chromogenic medium that has been developed for the detection and isolation of carbapenemase producing Enterobacteriaceae (CPE). Nosocomial infections due to CPE are particularly difficult due to the limited treatment options. Therefore, this medium is designed to simplify the detection of CPE carriers and to allow for improved monitoring of high risk patient groups. The distinctive colonial colouration of the various species can reduce the need for additional follow up testing allowing many positive results to be issued within 24 hours of receipt of the sample. All presumptive positive colonies should be confirmed for carbapenemase production. Typical colour reactions are as follows: Escherichia coli – Red/Pink colonies; Klebsiella spp., Enterobacter spp., & Citrobacter spp. – Metallic blue colonies; Other Gram –ve CPE – Colourless colonies; Carbapenem sensitive bacterial species, Gram +ve bacterial species & yeasts – Inhibited.
  • Recent developments in culture media have given rise to the use of chromogenic substrates as a means of differentiating bacteria particularly among the coliform group of organisms. Colorex™ UTI has been developed primarily for use in the examination of urine specimens with the aim of simplifying the differentiation and presumptive identification of the main organisms, gram negative and gram positive, usually found in Urinary Tract Infections. It can however be used to differentiate organisms in other types of clinical specimens. The distinctive colonial colouration of the various species can reduce the need for additional follow up testing allowing many positive results to be issued within 24 hours of receipt of the sample. If necessary an Indole test for confirmation of Escherichia coli and TDA test for Proteus spp. can be performed directly from the medium.
  • This is a chromogenic medium for the isolation and presumptive identification of Staphylococcus aureus. Mauve colonies indicate Staph aureus following incubation (18 – 24 hours) at 37°C, other organisms, if not inhibited, are indicated by blue or colourless colonies. Studies have suggested that this media has a specificity and sensitivity of 99.4% and 95.5% respectively (Gaillot et al 2000).
  • About a quarter of pregnant women in the UK are estimated to carry Streptococcus agalactiae. As a result of this, babies become colonized with Streptococcus agalactiae (GBS) during labour and birth; the vast majority are unaffected by this colonization, however, a small percentage become infected with conditions such as eye infections, pneumonia, septicaemia or meningitis. Colorex™ StrepB Agar is a chromogenic media that presumptively identifies Streptococcus agalactiae (mauve/red colonies) after 18-24 hours incubation in aerobic conditions. Enterococci are differentiated by the formation of blue colonies; other organisms are inhibited or colourless. NB: Some strains of Group A, C & G streptococci may also produce mauve colonies. Therefore, final identification may require additional testing.
  • Traditional methods for the isolation of Vibrio spp. (e.g. TCBS medium) are labour intensive and not particularly sensitive. Colorex™ Vibrio allows for the easy differentiation of V.parahaemolyticus from V.cholerae and V.vulnificus and other Vibrio spp. at the initial isolation stage while retaining a higher level of sensitivity than conventional methods. V.parahaemolyticus produces colonies with a mauve colouration while V.cholerae and V.vulnificus produce colonies with a blue colouration. Colorex™ Vibrio is a highly selective medium with most major Enterobacteriaceae spp. and Gram positive organisms being inhibited during incubation.
  • Vancomycin-resistant Enterococcus (VRE) infections are especially aggressive and have been associated with mortality rates approaching 60% to 70%. They are now the second-leading cause of nosocomial infections in the U.S., and their prevalence is increasing worldwide. Resistance to vancomycin has the potential to be transferred from bacteria to bacteria. Cross-resistance is mediated by plasmids and transposons, which may transfer the genes associated with resistance to other much more aggressive pathogens, such as staphylococci and streptococci. Three principal types of vancomycin resistance are found in Enterococcus spp.; VanA, VanB and VanC genotypes. VanA and VanB types account for most significant infections in clinical settings, involving E.faecium and E.faecalis. VanC resistance is a low-level intrinsic resistance found in other Enterococcus spp. The Colorex™ VRE media is another chromogenic media in the Colorex™ range, enabling presumptive identification of vancomycin resistant Enterococci by the formation of mauve/pink coloured colonies (for VanA and VanB genotypes) and blue coloured colonies (for VanC genotypes) after 18-24 hours incubation.
  • Middlebrooks 7H10 Selective Medium is an Agar based medium for the isolation of Mycobacteria spp from clinical specimens. It differs from Middlebrooks 7H11 Agar in that it has a lower concentration of Malachite Green, which is said by some workers to make it more suitable for primary isolation. The medium is complex but includes L-Glutamic Acid, Ammonium Sulphate, Sodium Citrate, Pyridoxine and Biotin as growth factors and Magnesium Sulphate, Ferric Ammonium Citrate as sources of trace ions. Further enrichment is provided by the addition of Oleic Acid, Albumen and Dextrose and it is made selective by the inclusion of Ticarcillin, Polymixin B, Trimethoprim and Amphotericin B. As with egg media Glycerol is included to enhance the growth of the Mycobacteria and Malachite Green is incorporated to provide a colour contrast between the colonies and the medium as well as contributing some inhibitory effect on organisms other than mycobacteria.  
  • This is a chromogenic medium based on CLED that has been developed to allow differentiation and presumptive identification of organisms typically found in urinary tract infections. Reduced electrolyte concentration prevents swarming of Proteus spp. A sophisticated binary chromogenic system and supplementation with tryptophan allows differentiation of Enterococcus spp. (turquoise colonies), Proteus spp. (clear colonies with a brown halo), Enterobacter spp. (metallic blue colonies), Staphylococcus spp. (white colonies), and E. coli (purple colonies).
  • Recent developments in culture media have given rise to the use of chromogenic substrates as a means of differentiating bacteria particularly among the coliform group of organisms. This is one such medium and has been developed with the aim of simplifying the differentiation and presumptive identification of the main organisms usually found in Urinary Tract Infections. Based on the traditional CLED Medium, to prevent the swarming of Proteus spp, two chromogens are present in the medium. One allows the detection of enterococci giving rise to blue colonies whilst the second results in purple colonies of E. coli. Phenylalanine and Tryptophan are also included as indicators of Tryptophan deaminase activity producing brown colonies of Proteus spp. This media is an opaque version to aid differentiation and presumptive identification of the bacteria isolated.