Part of Thermo Fisher Scientific

Thermo Scentific
 
 
 

Material Safety Data Sheet

Organisms

Organisms this product works with:

Dehydrated Culture Media

MACCONKEY AGAR (WITHOUT SALT)

Code: CM0507

A differential medium on which swarming of Proteus species is suppressed. Recommended for urine examination.

Typical Formula*

gm/litre

Peptone

20.0

Lactose

10.0

Bile salts

5.0

Neutral red

0.075

Agar

12.0

pH 7.4 ± 0.2 @ 25°C

 
* Adjusted as required to meet performance standards

Directions
Suspend 47g in 1 litre of distilled water. Bring to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes. Mix well before pouring. Dry the surface of the gel before inoculation.

Description
This medium has the same formulation as MacConkey Agar (CM0007) except that it does not contain added salt and therefore provides a `low electrolyte medium’ on which most Proteus species do not spread. For this reason the medium has found particular favour for use in the examination of urine so that overgrowth of other organisms is prevented.

Colonial Characteristics
After 24 hours at 35-37°C typical colonies are as follows:

Organism

Colour

Remarks
Escherichia coli
red
non-mucoid
Aerobacter aerogenes
pink
mucoid
Enterococcus species

red

minute, round
Staphylococcus species
pale pink
opaque
Pseudomonas aeruginosa
green/brown
fluorescent growth

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 plates of medium at 2-8°C.

Appearance
Dehydrated medium: Straw pink coloured powder
Prepared medium: Dark red coloured gel

Quality control

Positive controls:

Expected results

Enterococcus faecalis ATCC® 29212 *

Good growth; pink/red-coloured colonies

Staphylococcus aureus ATCC® 25923 *Good growth; pale pink-coloured colonies

Negative control:

Uninoculated medium

No change

*This organism is available as a Culti-Loop®

Precautions
The colonial characteristics described give presumptive identification only of the isolated organisms. It is necessary to subculture and carry out confirmation tests for final identification.
To enhance the pigment of suspected Staphylococcus aureus, hold the plates on the bench at ambient temperature for 12-18 hours.
This medium may produce a discrete precipitate on cold storage of 2 - 10°C. This in no way affects the performance of the medium.

References
See MacConkey Agar (CM0007)

ATCC® is a registered trademark of American Type Culture Collection.

 
©2001 - 2021 Oxoid Limited, All rights reserved.
Copyright, Disclaimer and Privacy Policy | Conditions of Sale | About Us | Cookies
Thermo Fisher Scientific Inc.