Cetrimide agar is a type of agar used for the selective isolation of the

gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wa ...

bacterium, ''

Pseudomonas aeruginosa ''Pseudomonas aeruginosa'' is a common encapsulated, gram-negative, aerobic–facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, ''P. aerug ...

''.http://www.bd.com/ds/productCenter/297882.asp "Cetrimide Agar Base • Pseudosel Agar". Accessed May 3, 2008. As the name suggests, it contains

cetrimide Cetrimide, or alkyltrimethylammonium bromide, is an antiseptic which is a mixture of three quaternary ammonium compounds: tetradonium bromide (TTAB or MITMAB), cetrimonium bromide (CTAB), and laurtrimonium bromide (DTAB or LTAB). It was first d ...

, which is the selective agent against alternate microbial flora. Cetrimide also enhances the production of ''Pseudomonas'' pigments such as

pyocyanin Pyocyanin (PCN−) is one of the many toxic compounds produced and secreted by the Gram negative bacterium ''Pseudomonas aeruginosa''. Pyocyanin is a blue secondary metabolite, turning red below pH 4.9, with the ability to oxidise and reduce other ...

and

pyoverdine Pyoverdines (alternatively, and less commonly, spelled as pyoverdins) are fluorescent siderophores produced by certain pseudomonads. Pyoverdines are important virulence factors, and are required for pathogenesis in many biological models of inf ...

, which show a characteristic blue-green and yellow-green colour, respectively.http://www.condalab.com/pdf/1102.pdf "Cetrimide Agar Base". Accessed May 3, 2008. Cetrimide agar is widely used in the examination of cosmetics, pharmaceuticals and clinical specimens to test for the presence of ''Pseudomonas aeruginosa''.

References

External links

Cetrimide Agar Description & Formulation
Biochemistry detection reactions Cell culture media Microbiological media {{Microbiology-stub