Ürün Açıklaması

A selective medium based on the formulation of Druggan, Forsythe & Iversen for the isolation of Cronobacter sakazakii (formerly Enterobacter sakazakii).

Application(s): Industrial, Food, Dairy
Organism(s): Cronobacter sakazakii

Cronobacter sakazakii (formerly Enterobacter sakazakii) is a member of the Enterobacteriaceae family and has been associated with serious outbreak infections in neonates (premature infants) which have been fed on infant formula milk. Although rarely causing infections in immunocompetent adults, C. sakazakii has been implicated in sepsis, meningitis and necrotising enterocolitis with a high death rate in neonates. This opportunistic pathogen is common in the environment and its ability to survive desiccation presents a significant risk for post pasteurisation contamination and survival in spray dried milk products.

Based on the formulation described by Druggan, Forsythe and Iversen, Harlequin^TM Cronobacter Sakazakii Agar is a medium on which Cronobacter sakazakii appears to constitutively express high levels of α-glucosidase. This enzyme hydrolyses the chromogenic substrate 5-bromo-4-chloro-3-indolyl-α-D-glucopyranoside present in the medium, producing green coloured colonies. Other Enterobacteriaceae such as E. coli do not express strong α-glucosidase activity and appear colourless. Hydrogen sulphide producing organisms, such as Salmonella, and Proteus spp. appear grey, brown or black on this formulation due to the production of precipitated ferrous sulphate, which results from the hydrogen sulphide produced by these organisms interacting with ferric ions in the medium. This reaction prevents the weakly α-glucosidase positive Proteus vulgaris from appearing as green on the medium.

Selectivity is achieved from the inclusion of sodium desoxycholate which serves to inhibit the growth of most Gram-positive organisms.