KM0060 – Lowenstein-Jensen Medium

//KM0060 – Lowenstein-Jensen Medium

KM0060 – Lowenstein-Jensen Medium

Lowenstein-Jensen medium is based on the original formulation of Lowenstein that was subsequently modified by Jensen. It is used with fresh egg and glycerol for the isolation and presumptive identification of Mycobacterium spp., particularly Mycobacterium tuberculosis, from clinical samples.
L-Asparagine and Potato starch are sources of nitrogen and vitamins in the medium. Potassium hydrogen phosphate and magnesium sulphate enhance organism growth and act as buffers. Sodium citrate and malachite green are selective agents that have inhibitory effects on organisms other than the mycobacteria. Malachite green is also incorporated into the medium to provide a colour contrast between the colonies and the medium.
The required addition of egg emulsion provides the fatty acids and protein required for the metabolism of mycobacteria. Glycerol is also added which is said to enhance the growth of Mycobacterium tuberculosis however other strains of mycobacteria, particularly Mycobacterium bovis, may be inhibited by its presence.
Subsequently, sodium pyruvate (12.5 g/600ml) may be used as an alternative to glycerol to encourage the growth of Mycobacterium bovis.

 

SKU: KM0060 Category:

Additional Information

Shelf Life (days)

Storage Temp (°C)

Dehydrated Medium Appearance

Prepared Medium Appearance

Dehydrated Medium Colour

Prepared Medium Colour

Dehydrated PH

Prepared PH

Product Description

Organisms Ref. No Result
Mycobacterium tuberculosis ATCC 35818 Growth
Mycobacterium kansasii NCTC 13024 Growth
Mycobacterium fortuitum NCTC 10394 Growth
Mycobacterium intracellulare NCTC 10682 Growth

 

Formula*

g/L
L-Asparagine 3.6
Potassium di-hydrogen phosphate 2.4
Magnesium sulphate 0.24
Sodium citrate 0.6
Malachite green 0.4
Potato starch 30.0
Total 37.2
*Adjusted/supplemented as required to meet performance requirements

Preparation

Suspend 37.2g of the medium in 600ml of deionised / purified water. Add 12ml of glycerol and allow the medium to mix for 10 minutes. Sterilise at 121°C for 15 minutes. Cool to 45-50°C.
Aseptically prepare 1000ml of homogenous egg emulsion using fresh eggs. Avoid introducing air into the egg emulsion during
collection and preparation.
Aseptically add the 600ml of Lowenstein-Jensen medium to the 1000ml of egg emulsion. Mix gently and dispense into sterilescrew-capped tubes. Place in a sloped position and heat for 45 minutes at 85°C until set.