Liofilchem® Lowenstein-Jensen Medium

Lowenstein-Jensen Medium is a classical egg-based medium recommended for the isolation and cultivation of Mycobacteria, particularly Mycobacterium tuberculosis, from clinical specimens or pure cultures. It supports the growth of both slow-growing and fast-growing mycobacteria while inhibiting contaminants with the selective action of malachite green.

This medium must be freshly prepared, supplemented with glycerol and whole eggs, and coagulated using an inspissator. It is ideal for use in diagnostic microbiology laboratories for tuberculosis (TB) screening, culture confirmation, and drug susceptibility testing.

Typical Formula (per 600 mL)

Preparation Instructions

1. Suspend 37.2 g of powder in 600 mL of distilled water.
2. Add 12 mL of glycerol supplement (REF 80021).
3. Heat until fully dissolved.
4. Autoclave at 121°C for 15 minutes.
5. Cool to 45–50°C and aseptically add 1,000 mL of freshly collected whole eggs.
6. Dispense into sterile tubes.
7. Coagulate medium using an inspissator at 85°C for 45 minutes in slanted position.

Technique

• Inoculate duplicate tubes with clinical or pure cultures using a sterile loop.
• Streak gently on the surface.
• Incubate at 36 ± 1°C for 2–12 weeks in a CO₂-enriched, dark environment with loosened caps.

Quality Control (QC)

Performance Notes

Negative results do not exclude active mycobacterial infection. Common causes of culture failure may include:

• Improper specimen collection (e.g., saliva instead of sputum)
• Over-decontamination or heat damage to mycobacteria
• Contamination suppressing growth
• Improper incubation conditions (oxygen or CO₂ levels)

Storage Conditions

• Dehydrated medium: Store at 10–30°C in a dry, tightly sealed container
• Prepared medium: Store tubes at 2–8°C, protected from contamination
• Do not use past expiration or if deterioration is observed

Applications

• Primary isolation of M. tuberculosis from clinical specimens
• Differentiation and maintenance of mycobacterial cultures
• Antimicrobial susceptibility testing
• Culture confirmation in tuberculosis diagnostics

Liofilchem® Lowenstein-Jensen Medium remains the gold standard for solid medium-based cultivation of Mycobacteria, offering selectivity, stability, and reproducibility in both clinical and research laboratories. When used according to proper protocols, it enables reliable detection of mycobacterial pathogens, supporting accurate TB diagnosis and public health surveillance.