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Brilliance MRSA AGAR

Code: PO1162

Brilliance™ MRSA is a new and improved* chromogenic screening plate for MRSA. The medium combines excellent sensitivity with the simplicity of a chromogenic plate to create an invaluable tool in the implementation of infection control policy.

Only avialable in certain territories. Please speak to your local Oxoid supplier.

* Adjusted as required to meet performance standards

Description
The importance of screening as part of an effective infection control programme to limit the spread of MRSA is well recognised. Speed and accuracy of results are critical aspects of this. Colonised patients can be accurately targeted for isolation and appropriate treatment as early as possible. Resource is not wasted on patients who are not colonised.

A variety of media are used to screen for MRSA. These include Mannitol Salt Agar with oxacillin and extra salt, Baird-Parker Agar with ciprofloxacin and Bromocresol Purple Agar with aztreonam and oxacillin. Most of these have issues of sensitivity or specificity, and all require up to 48 hours incubation.

In recent years, MRSA screening technology has improved. Since its development by Oxoid, Oxacillin Resistance Screening Agar (ORSA) has been widely adopted as an MRSA screening medium. The sensitivity of this product at 48 hours has recently been shown to be comparable with that of some new chromogenic MRSA products^1,2. However, a small number of MRSA do not ferment mannitol, while S. haemolyticus can give false positive reactions. These issues were overcome by Oxoid’s original Chromogenic MRSA Agar. As part of Oxoid continuous improvement policy, further research and development work has produced a new formulation which, while maintaining the high sensitivity of the previous chromogenic MRSA agar, results in increased selectivity and stability.

The improved formulation of the new Brilliance MRSA Agar ulitises the same novel chromogen to yield a demin blue colour as a result of phosphatase activity. This enzyme is present in all MRSA. To allow the medium to differentiate MRSA accurately, it contains a combination of antibacterial compounds designed to inhibit the growth of a wide variety of competitor organisms and MSSAs. This combination includes a new surrogate marker for meticillin resistance which replaces cefoxitin. Also included are compounds that encourage the production of MRSA pathogenicity marker, ensuring expression of the phosphatase enzyme and so providing enhanced sensitivity and specificity.

Brilliance MRSA Agar can be inoculated from a screening swab taken from hospital patient or staff, from an isolated colony or from a liquid suspension. MRSA grows as denim blue colonies which are very easy to read against the light coloured, opaque background. Plates are incubated at 37ºC, and provide high sensitivity and specificity, with results available in just 18 hours. This allows a rapid response, so enabling the patient to receive the most appropriate treatment as early as possible. Accuracy minimises costs, by helping to ensure that only those in need receive what can be costly treatment.

Technique
Brilliance MRSA Agar can be inoculated from screening swabs taken from hospital patients or staff, an isolated colony or from liquid suspension, according to local guidelines. The medium should be allowed to warm to room temperature before inoculation. Incubate for 18-20 hours at 37ºC. There is no need to incubate beyond 24 hours. Denim blue colonies are presumptive positive for MRSA. Identifications as S. aureus can be confirmed with Staphytect Plus (DR0850) or Dryspot Staphytect Plus (DR0100), and PBP2′ (DR0900) can be used to confirm MRSA.

For further instructions on the use and interpretation of Brilliance MRSA Agar, simply download the data sheet (733KB) in PDF format.

Storage conditions and shelf life
Brilliance MRSA Agar plates should be stored in the original packaging at the temperature stated on the pack or product specification, and protected from direct light. When stored as directed, the unopened product will remain stable until the expiry date on the label.

Appearance
Prepared medium: Pale, off-white, opaque gel medium in Petri dishes

Quality Control

Precautions
Brilliance MRSA Agar is for in vitro diagnostic use only, by trained individuals. Do not use beyond the expiry date given on the label, or if the product shows any sign of deterioration.

Sterilise specimens, equipment and media properly after use.

Limitations
Organisms with atypical resistance or enzyme expression patterns may give anomalous results.

Refs
1. Perry, J.D., Davies, A., Butterworth, L.A., Hopley, A.L.J., Nicholson, A. and Gould, F.K. ,”Development and evaluation of a chromogenic agar medium for methicillin-resistant Staphylococcus aureus,” J. Clin. Micro. (2004) 42 (10), 4519-4523.
2. Davies, A., Perry, J.D., Butterworth, L. A., Nicholson, A. and Gould, F. K, “An evaluation of MRSA ID: a new chromogenic medium for the isolation and identification of methicillin-resistant Staphylococcus aureus,” Poster by Microbiology Dept, Freeman Hospital, Newcastle-Upon Tyne.

ATCC® is a registered trademark of American Type Culture Collection

Brilliance MRSA PDF (733KB)