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CHROMagar Staph Aureus plates
Cat. No. PD 235
90mm Prepared plates
Pkg.: 20 units in a box (2X10)
Expiry Date: Printed on label and on the item
Storage
Store at 2-80 C. Protected from light.
Composition (g/L)
Agar 15; Peptones & salts 75; Special chromogenic mix 2.5.
Intended Use
CHROMagar Staph aureus utilizes a selective and differential medium developed by CHROMagar, Paris, designed for the detection and identification of S. aureus without the need of further testing.
The medium can be used for the isolation of S. aureus from clinical specimens, from food and from environmental sources.
Principle
The formulation includes selected peptones that supply the nutrients.
A mixture of chromogenic substrates release an insoluble colored compound when hydrolyzed by specific enzymes from S. aureus, leading to the growth of the microorganism in mauve colonies surrounded by a mate halo. The addition of selective agents to the medium inhibits the growth of most gram-negative bacteriae, S. epidermidis and yeasts.
Procedure
1. For clinical specimens: Wounds, sputum, nasal, bronchoalveolar lavage, tracheal and drainage aspirates and blood culture supernatant samples, use standard collection procedures.
2. If the plates have been refrigerated, allow to return to room temperature before inoculation.
Streak sample onto plate and incubate aerobically at
35 ± 20 C for 24 hours in an inverted position (agar-side up). Incubation beyond 24 hours may potentially increase the number of false positive results.
3. For Food, Cosmetics and Water testing, follow standard recommended procedures.
Interpretation of Results
S. aureus strains grow in pink to mauve colonies that may show a mate halo.
Yeasts and gram-negative organisms are partially to completely inhibited. Resistant gram-negative bacilli could appear as small blue colonies.
Other Gram-positive organisms are inhibited, or grow in colorless, blue, green or aqua-green colonies.
Procedure Limitations
· Occasional strains of coagulase negative staphylococci
(S. intermedius, S. cohnii), as well as corynebacteria may produce mauve colonies.
· Confirmation of S. aureus I.D. may be accomplished by coagulase or agglutination tests.
· Minimize as possible exposure of CHROMagar MRSA to light before and during incubation in order to avoid destroying the chromogens. Keep plates within the original pack.
· Incubation beyond 24 hours may potentially increase the number of false positive results
Disposal
Used contaminated test material should be handled by standard decontamination methods such as autoclaving or incineration.
Authorized EU representative:
MedNet GmbH, Eschstraße 19, D-48167 Münster, Germany
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