Part of Thermo Fisher Scientific
Organisms this product works with:
Other products used in the isolation of Cronobacter:
CRONOBACTER SCREENING BROTH (CSB)
A novel enrichment broth for the detection of Cronobacter (formerly E. sakazakii) from food and environmental samples. To be used in conjunction with Chromogenic Cronobacter Isolation (CCI) Agar (CM1122)
CODE: CM1121
Typical Formula* |
gm/litre |
Peptone |
10.0 |
Meat extract |
3.0 |
Sodium chloride |
5.0 |
Bromocresol purple |
40 mg |
Sucrose |
10.0 |
pH 7.4 ± 0.2 @ 25°C |
VANCOMYCIN SUPPLEMENT (5mg)
CODE: SR0247E
Vial contents: (each vial sufficient for 500ml of medium) |
per vial
|
per litre
|
Vancomycin |
5mg
|
10mg
|
Directions
Dissolve 14.02g in 500ml of distilled water. Sterilize by autoclaving at 121°C for 15 minutes. Cool to approximately 50°C, and aseptically add the contents of 1 vial of Vancomycin Supplement (5mg) (SR0247E) reconstituted as directed. Mix well and aseptically dispense into sterile containers.
Description
Cronobacter (formerly Enterobacter sakazakii) are Gram-negative rod-shaped members of the Family Enterobacteriaceae that have been implicated in outbreaks of disease in premature infants (neonates), causing sepsis, meningitis and necrotising enterocolitis. Neurological damage can be permanent, and the death rate is reported to be as high as 40-80%1.
Cronobacter spp. have been isolated at low levels from powdered infant formulae, and the organisms’ high tolerance to desiccation provides a competitive advantage in the dry environments of milk powder factories, increasing the risk of product contamination2.
The ongoing development of a new horizontal CEN-ISO standard method for the detection of Cronobacter spp by the ISO/TC 34, SC 9Ad hoc group for E. sakazakii, addresses issues such as the scope of the method, reliability of identification criteria and improvements to the media1. In anticipation of these future needs, Oxoid has launched new Cronobacter Screening Broth (CSB) (CM1121) and Chromogenic Cronobacter Isolation (CCI) Agar (CM1122).
Cronobacter Screening Broth was specifically designed by Iversen et al.3 to be used in conjunction with chromogenic media. It allows presumptive Cronobacter-positive samples to be identified before the selective plating step, and also allows Cronobacter-negative products to be released at least 24 hours earlier than with other standard methods. This is achieved by the inclusion of sucrose and the pH indicator bromocresol purple. Whilst Cronobacter spp. can ferment sucrose, most other Enterobacteriaceae, which grow as false positives on chromogenic agars, cannot. Consequently, a yellow/orange coloration in the broth after incubation (due to sucrose fermentation) indicates presumptive Cronobacter. If the broth is still purple in colour after incubation, the sample is presumed to be negative for Cronobacter.
Technique
Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label
Store the prepared medium at 2-8°C
Appearance
Dehydrated medium: Straw coloured, free-flowing powder
Prepared medium: Purple coloured solution
Quality Control
Positive Controls |
Expected results
|
Cronobacter sakazakii ATCC® 12868 |
Turbid growth, yellow/orange colour
|
Cronobacter sakazakii ATCC® 29004 |
Turbid growth, yellow/orange colour |
Cronobacter muytjensii ATCC® 51329* |
Turbid growth, yellow/orange colour |
Negative Controls |
|
Escherichia coli ATCC® 25922* |
Turbid growth, purple colour |
Staphylococcus aureus ATCC® 25923* |
Inhibited or no growth |
References