PURPOSE OF USING CHROMOGENIC CULTURE MEDIA
Dehydrated media serves as a nutrient system for the cultivation of microorganisms. However, the aforementioned role is just one. By adding chromogenic substrate, differentiation and selection of microorganisms becomes more convenient.
HOW DOES IT WORK
Chromogenic culture media contains nutrients such as peptones, amino acids, yeast extract, minerals and vitamins, as well as inhibitors and solidifier e.g. agar and Chromogenic mixtures (chromogens) depending upon each medium. The chromogenic mixture contains chromogenic substrates as Salmon -GAL, X-Gal, X-glucuronides, etc. Certain enzymes, produced by some bacteria, cleave these substrates, resulting in the different colouration of certain bacterial colonies.
BENEFITS
1. Majorly the chromogenic is known for its rapidness, accuracy and simplicity involved during diagnosis.
2. The chromogenic saves time and labour work. When compared with traditional methods, the chromogenic deliver results in shorter time for both negatives screens & presumptive positives. Some chromogenic culture media gives confirmed results within 24 hours
3. Mostly, the result interpreted from chromogenic media does not require further testing and eliminates the need of subculture and further biochemical test for identification pathogenic agent.
4. On a single medium, one can identify more than one organism. This is the reason for the chromogenic being so cost effective.
CHROMOGENIC INDEXING
1. TM 1197|CHROMOGENIC CANDIDA AGAR
SYMBOL |
CULTURE NAME |
ATCC |
APPEARANCE OF COLONY |
A |
Candida albicans |
10231 |
Light green |
B |
Candida glabrata |
2001 |
Light white to purple |
C |
Candida tropicalis |
1369 |
Blue-Metallic Blue |
D |
Candida Krusei |
34135 |
Purple-Pink |
|
 |
2. TM 1339|CHROMOGENIC E.COLI AGAR
SYMBOL |
CULTURE NAME |
ATCC |
APPEARANCE OF COLONY |
A |
Escherichia coli |
25922 |
Bluish green |
B |
E. aerogenes |
13048 |
Colourless |
|
 |
3. TM 1858|CHROMOGENIC COLIFORM AGAR
SYMBOL |
CULTURE NAME |
ATCC |
APPEARANCE OF COLONY |
A |
Escherichia coli |
25922 |
Dark blue to violet colonies |
B |
Citrobacter freundii |
8090 |
Pink to red colonies |
C |
Salmonella enteritidis |
13076 |
Colourless colonies |
D |
E aerogenes |
13048 |
Pink to red colonies |
|
 |
4. TM 1199|CHROMOGENIC UTI AGAR
SYMBOL |
CULTURE NAME |
ATCC |
APPEARANCE OF COLONY |
A |
Escherichia coli |
25922 |
Pink- Purple |
B |
Enterococcus faecalis |
29212 |
Blue |
C |
Staphylococcus aureus |
25923 |
Cream yellow |
D |
Pseudomonas aeruginosa |
27853 |
Colourless (greenish pigment may be observed) |
E |
Klebsiella pneumoniae |
13883 |
Bluish Purple |
|
 |
Complete list of Chromogenic Culture Media: Click Here