Sigma-Aldrich PSEUDOMONAS MILLICHROME# PLUS AGAR

Pseudomonas Millichrome^™ plus Agar is a selective media for the isolation and detection of Pseudomonas. The distinguishing feature of these media is the inclusion of a chromogenic substrate mix that produces visible color changes upon the enzymatic activity of Pseudomonas.Millichrome^™ chromogenic media is a specialized type of culture medium used to detect and isolate specific groups of bacteria based on their ability to produce enzymes with chromogenic substrates. Peptones contribute nitrogenous nutrients and other essential growth factors for cellular growth. Salts maintain osmotic balance and provide crucial ions. The chromogenic and selective mixture consists of substrates that change color when characteristic enzymes cleave them, allowing for differentiation, and it also contains selective agents to inhibit other organisms. Agar is included as a solidifying agent.

Pseudomonas Millichrome^™ plus Agar Base is a selective chromogenic culture medium intended for use in the qualitative direct detection, differentiation and presumptive identification of pathogenic biotypes of Pseudomonas sp. from various samples

Preparation of 1L media:

• Disperse slowly 45.5 g of powder base in 1 L of purified water.
• Stir until agar is well thickened.
• Heat and bring to boiling (100 °C) while swirling or stirring regularly.

DO NOT HEAT TO MORE THAN 100 °C. DO NOT AUTOCLAVE AT 121 °C.
Warning : If using an autoclave, do so without pressure.
Advice: For the 100 °C heating step, mixture may also be brought to a boil in a microwave oven: after initial boiling, remove from oven, stir gently, then return to oven for short repeated bursts of heating until complete fusion of the agar grains has taken place (large bubbles replacing foam).

• Cool in a water bath to 45-50 °C, swirling or stirring gently.
• Pour medium into sterile Petri dishes.
• Let it solidify and dry.

Store prepared media at 2-8°C, protected from direct light and dehydration (max. 1 month) or 1 day at room temperature.Store dehydrated powder, in a dry place, in tightly sealed containers at 2-25°C.

The Pseudomonas colonies including P. aeruginosa form blue-green colonies after 48 h of incubation at an optimal growth temperature of 30°C, whereas the growth of other Enterobacteriaceae is inhibited or forms mauve to violet colonies after incubation at the same temperature.

MilliChrome is a trademark of Merck KGaA, Darmstadt, Germany