Liofilchem® Lowenstein Jensen + Ethambutol, 9 mL

The Liofilchem Lowenstein Jensen + Antibiotic Medium is a specialized egg-based solid medium used for the isolation, cultivation, differentiation, and drug susceptibility testing (DST) of Mycobacterium tuberculosis and other Mycobacterium species. It is the gold standard for drug susceptibility testing using the proportion method.

Key Features

1. Drug Susceptibility Testing (DST):
   • Contains specific antibiotics or anti-mycobacterial agents for testing resistance in Mycobacterium tuberculosis.
   • Gold standard for proportion methods used to detect drug resistance.
2. Enriched Nutrient Medium:
   • Supports robust growth of Mycobacteria with nutrients derived from egg suspension, glycerol, and potato flour.
3. Selective for Mycobacteria:
   • Malachite green inhibits contaminant bacteria, ensuring selectivity for Mycobacterium species.
4. Enhanced Differentiation and Identification:
   • Can be supplemented with p-nitrobenzoic acid (PNB) or thiophene-2-carboxylic acid hydrazide (TCH) for differentiating between the Mycobacterium tuberculosis complex (MTC) and non-tuberculous mycobacteria (NTM).
5. Longer Incubation Time:
   • Ideal for slow-growing Mycobacteria, requiring up to 8 weeks of incubation in a CO₂-enriched atmosphere.

Composition (per 600 mL water)

Applications

1. Drug Susceptibility Testing (DST):
   • Evaluate resistance to first-line antibiotics (e.g., isoniazid, rifampicin, ethambutol, streptomycin).
   • Assess susceptibility to second-line drugs for multidrug-resistant tuberculosis (MDR-TB).
2. Isolation and Cultivation:
   • Support the growth of slow-growing Mycobacterium tuberculosis from clinical specimens.
3. Species Differentiation:
   • Supplemented with PNB: Inhibits growth of MTC, allowing NTM identification.
   • Supplemented with TCH: Used to confirm MTC when performed alongside other biochemical tests.
4. Clinical Diagnosis:
   • Routine use in laboratories for the primary isolation of tuberculosis-causing bacteria.
5. Environmental and Veterinary Microbiology:
   • Used for isolating Mycobacteria from environmental samples and veterinary specimens.

Procedure

1. Sample Inoculation:
   • Use a smear-positive specimen (direct method) or subculture from primary culture (indirect method).
   • Inoculate the strain onto drug-containing Lowenstein Jensen + Antibiotic Medium and onto a drug-free LJ control medium.
2. Incubation:
   • Incubate at 35 ± 2°C in a CO₂-enriched atmosphere (5-10%).
   • Loosen tube caps for the first week to allow CO₂ circulation.
   • Tighten caps to prevent dehydration after the first week.
3. Observation:
   • Examine weekly for colony formation.
   • Susceptible organisms will show reduced or no growth on drug-containing medium, whereas resistant strains will grow normally.
4. Interpretation of Results:
   • Refer to standard proportion methods and clinical references for interpreting drug resistance patterns.

Appearance

Storage Conditions

• Temperature: Store at 2–8°C, protected from light.
• Shelf Life: 4 months from the date of manufacture.

Quality Control

Advantages

1. Gold Standard for DST:
   • Recognized as the gold standard for drug susceptibility testing in tuberculosis diagnosis.
2. Enhanced Growth of Mycobacteria:
   • Nutrient-rich medium ensures superior growth compared to agar-based media like Middlebrook 7H10/7H11.
3. Reliable Selectivity:
   • Malachite green effectively inhibits contaminant bacteria, maintaining medium selectivity.
4. Flexibility for Differentiation:
   • Can be supplemented with PNB, TCH, or pyruvic acid to differentiate MTC and NTM.
5. Long Shelf Life and Stability:
   • Maintains performance for up to 4 months under proper storage.

Precautions

• For in vitro diagnostic use only.
• Use by trained laboratory professionals following appropriate biosafety precautions.
• Dispose of contaminated materials per local and national regulations.

References

1. Salman et al. (2012). Direct DST for Multidrug Resistance Using Bactec MGIT 960. J. Clin. Microbiol.
2. Murray P.R., Baron E.J., Jorgensen J.H., Landry M.L., Pfaller M.A. (2007). Manual of Clinical Microbiology, 9th Edition.
3. Giampaglia CM et al. (2005). Rapid differentiation of MTC using PNB and TCH. Int J Tuberc Lung Dis.
4. Clinical and Laboratory Standards Institute (2004). Quality Control for Commercially Prepared Media. CLSI M22-A3.

The Liofilchem Lowenstein Jensen + Antibiotic Medium is a reliable and selective medium for the cultivation, differentiation, and susceptibility testing of Mycobacterium tuberculosis, making it a cornerstone in tuberculosis diagnostics.