Liofilchem® Middlebrook 7H10 Agar Base

Liofilchem Middlebrook 7H10 Agar is a moderately selective, solid medium designed for the isolation, cultivation, and drug susceptibility testing (DST) of Mycobacterium species, particularly Mycobacterium tuberculosis. It combines essential nutrients, trace elements, and supplements (OADC and Glycerol) to provide an enriched environment that supports the growth of slow-growing Mycobacteria.

Key Features

1. Selective for Mycobacteria
   • Incorporates Malachite green to suppress non-mycobacterial contaminants while maintaining optimal conditions for Mycobacterium spp. growth.
2. Nutrient-Rich Composition
   • Enriched with Middlebrook OADC Supplement and Glycerol Supplement for enhanced growth of M. tuberculosis.
3. Optimized for Drug Susceptibility Testing
   • Suitable for drug susceptibility testing using anti-tuberculous agents, ensuring reproducible results for clinical diagnostics.
4. Consistent Performance
   • Agar-based media like Middlebrook 7H10 provide more reliable results compared to egg-based media, which may inactivate certain antibiotics.
5. Wide Applications
   • Used for primary isolation of M. tuberculosis, cultivation of pure mycobacterial strains, and antimicrobial resistance testing.

Composition (per liter of water)

Supplements Required

1. OADC Supplement:
   • Oleic acid, albumin, glucose, sodium chloride, and catalase.
   • Provides fatty acids, energy, and protection from toxic agents.
2. Glycerol Supplement:
   • Supplies glycerol as a carbon and energy source to enhance mycobacterial metabolism.

Preparation Instructions

1. Suspend 19.5 g of Middlebrook 7H10 Agar Base in 900 mL of distilled water containing 5 mL Glycerol Supplement.
2. Heat to boiling while stirring until fully dissolved.
3. Autoclave at 121°C for 15 minutes.
4. Allow the medium to cool to 45–50°C.
5. Aseptically add 100 mL of Middlebrook OADC Supplement and mix thoroughly.
6. Pour into sterile Petri dishes or slant tubes.

Applications

1. Primary Isolation and Cultivation
   • Effective for the isolation and growth of Mycobacterium tuberculosis and other slow-growing mycobacteria from clinical and environmental samples.
2. Drug Susceptibility Testing (DST)
   • Used to determine resistance of M. tuberculosis to anti-tuberculosis drugs, such as:
     • Isoniazid (INH)
     • Rifampicin (RIF)
     • Ethambutol (EMB)
     • Streptomycin (SM).
3. Pure Culture Maintenance
   • Suitable for cultivating pure mycobacterial strains for laboratory research and diagnostic purposes.
4. Differentiation and Morphological Studies
   • Facilitates observation of colony morphology, pigmentation, and identification testing.

Procedure

1. Specimen Processing
   • Decontaminate non-sterile specimens (e.g., sputum) to inhibit overgrowth of contaminants.
2. Inoculation
   • Inoculate specimens onto prepared Middlebrook 7H10 Agar slants or plates.
3. Incubation
   • Incubate at 35 ± 2°C in an aerobic atmosphere enriched with 5–10% CO₂.
   • Inspect weekly for up to 8 weeks.
4. Observation
   • Examine cultures for:
     • Colony growth.
     • Pigment production.
     • Morphological characteristics.
5. Identification
   • Perform biochemical or molecular tests for confirmatory identification of Mycobacterium species.

Advantages

1. Faster Growth:
   • Supports earlier growth detection compared to traditional egg-based media.
2. Reduced Contamination:
   • Malachite green prevents the growth of non-mycobacterial organisms.
3. Enhanced Drug Testing:
   • Reliable for antibiotic susceptibility testing with reproducible results.
4. Versatile Use:
   • Suitable for clinical, environmental, and research applications.
5. Nutrient-Rich Supplementation:
   • OADC and glycerol ensure optimal growth conditions for Mycobacterium tuberculosis.

Quality Control

Storage Conditions

Precautions

• For in vitro diagnostic use only.
• Use by trained personnel with appropriate biosafety precautions.
• Dispose of waste according to local and national regulations.

Liofilchem Middlebrook 7H10 Agar provides a reliable and nutrient-rich medium for the selective isolation, cultivation, and drug susceptibility testing of Mycobacterium tuberculosis and related species. Its agar-based formulation ensures faster growth, reduced contamination, and consistent performance compared to egg-based media, making it a valuable tool in clinical diagnostics and tuberculosis research.