HiCrome™ Enterobacter sakazakii Agar, Modified (HiCrome™ Cronobacter sakazakii Agar, Modified)

Composition**

Final pH ( at 25°C): 7.0±0.2

**Formula adjusted, standardized to suit performance parameters

# - Equivalent to Pancreatic digest of casein

Directions

Suspend 30.75 grams in 1000 ml distilled water. Heat to boiling to dissolve the medium completely. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. Cool to 45-50°C. Mix well and pour into sterile Petri plates.

Principle And Interpretation

Enterobacter species are widely distributed in nature occurring in fresh water, soil, sewage, plants, vegetables, animal and human feaces. *Cronobacter sakazakii has been closely associated with neonatal meningitis and sepsis (1). HiCrome™ Enterobacter sakazakii Agar, Modified is recommended by ISO Committee for the isolation and identification of *C.sakazakii (2). The chromogenic substrate (5-Bromo-4-chloro-3-indolyl α-D-glucopyranoside) is cleaved specifically (3) by *C.sakazakii resulting in the formation of blue green colonies. Other organisms, which do not cleave this substrate, produce colourless to slightly violet coloured colonies.

Casein enzymic hydrolysate and yeast extract provides nitrogenous and carbonaceous compounds, long chain amino acids, vitamins and other essential growth nutrients. Sodium chloride helps in maintaining the osmotic equilibrium of the medium. Sodium deoxycholate and crystal violet inhibits the accompanying gram-positive flora.

Key: *: Formerly known as Enterobacter sakazakii

Quality Control

Appearance Light yellow to pink homogeneous free flowing powder

Gelling Firm, comparable with 1.5% Agar gel

Colour and Clarity of prepared medium Light purple coloured, clear to slightly opalescent gel forms in Petri plates

Reaction Reaction of 3.07% w/v aqueous solution at 25°C. pH : 7.0±0.2

pH 6.80-7.20

Cultural Response M1641: Cultural characteristics observed after an incubation at 44±1°C for 22-26 hours.

Key: *: Formerly known as Enterobacter sakazakii

Storage and Shelf Life

Store dehydrated powder in tightly closed container and prepared medium at 2-8°C. Use before expiry period on the label.

Reference

1. Muytjens H. L., Zanen H. C., Sonderkamp H. J. et al, J. Clin Microbiol 18:115-120, 1983.
2. International Organization for Standardization. Milk and Milk products- Detection of Enterobacter sakazakii Draft ISO/ TS 22964, 2006 (E).