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Specifications:
| Application | Microbiology |
| Storage Temperature | 2-8°C |
| Product Type | Culture Medium |
| Product Brand | Liofilchem |
| Product Grade | Microbiology grade |
Selective and Differential Medium for Isolation and Identification of Enterobacteriaceae and Other Gram-Negative Bacteria
Liofilchem® MacConkey Agar is a selective and differential culture medium formulated for the isolation and differentiation of Gram-negative enteric bacilli, particularly from clinical specimens, pharmaceuticals, food, water, and materials of sanitary interest. It is especially suited for the identification of lactose-fermenting and non-lactose-fermenting bacteria in compliance with the harmonized methods of the USP, EP, and JP.
Intended Use
- Selectively isolates Gram-negative bacilli from mixed microbial populations.
- Differentiates lactose fermenters (e.g., E. coli, Klebsiella spp.) from non-lactose fermenters (e.g., Salmonella, Shigella, Proteus spp.).
- Widely used in clinical diagnostics, pharmaceutical quality control, and environmental microbiology.
Typical Composition (per Liter)
| Component | Concentration (g/L) |
|---|---|
| Pancreatic Digest of Gelatin | 17.0 |
| Peptone from Meat | 1.5 |
| Peptone from Casein | 1.5 |
| Lactose | 10.0 |
| Sodium Chloride | 5.0 |
| Bile Salts | 1.5 |
| Agar | 15.0* |
| Neutral Red (pH Indicator) | 0.03 |
| Crystal Violet (selective agent) | 0.001 |
| Final pH at 25°C | 7.1 ± 0.2 |
*Agar concentration adjusted for optimal gel strength.
Method Principle
- Peptones and digests supply nitrogen, amino acids, and vitamins.
- Lactose is the fermentable sugar used for differentiating enteric bacteria.
- Bile salts and crystal violet selectively inhibit Gram-positive organisms.
-
Neutral red serves as a pH indicator:
- Lactose fermenters → pink to red colonies
- Non-lactose fermenters → colorless colonies
Expected Cultural Characteristics
| Organism (ATCC®) | Colony Appearance |
|---|---|
| Escherichia coli 8739 | Pink colonies with bile precipitate halo |
| Klebsiella pneumoniae 13883 | Pink colonies |
| Salmonella Typhimurium 14028 | Colorless colonies |
| Shigella flexneri 12022 | Colorless colonies |
| Proteus mirabilis 12453 | Colorless colonies |
| Enterococcus faecalis 29212 | Small, opaque colonies or inhibited |
| Staphylococcus aureus 25923 | Inhibited |
Applications
- Detection of E. coli in non-sterile pharmaceutical products per USP/EP/JP harmonized methods
- Differentiation of enteric bacilli in clinical stool or urine samples
- Testing of food, wastewater, or environmental swabs
- Used as a subculture medium following enrichment in Tryptic Soy Broth and MacConkey Broth
Test Procedure
- Inoculate the specimen by streaking directly or from enrichment onto the agar surface.
- Incubate at 35 ± 2°C for 18–24 hours in aerobic conditions.
-
For harmonized pharmacopeial testing:
- Pre-enrich sample in TSB, then MacConkey Broth, followed by plating on MacConkey Agar.
Available Product Formats
| Product | Packaging | Ref. Code |
|---|---|---|
| MacConkey Agar, 90 mm plates | 20 plates | 10029 |
| MacConkey Agar, 90 mm plates | 100 plates | 10029* |
| Bottles (100 mL) | 6 bottles | 402240 |
| Bottles (200 mL) | 6 bottles | 412240 |
| Bottles (500 mL) | 6 bottles | 470090 |
| Dehydrated medium (100 g) | 1 container | 620028 |
| Dehydrated medium (500 g) | 1 container | 610028 |
| Dehydrated medium (5 kg) | 1 container | 6100285 |
Storage and Shelf Life
| Form | Storage | Shelf Life |
|---|---|---|
| Dehydrated Powder | 10–30°C (dry, sealed) | 4 years |
| Ready-to-use Bottles | 10–25°C, away from light | 2 years |
| Ready-to-use Plates | 10–25°C, away from light | 6 months |
Liofilchem® MacConkey Agar is a reliable and compliant medium for detecting Enterobacteriaceae and other Gram-negative organisms, providing clear colony differentiation based on lactose fermentation. Available in plates, bottles, and dehydrated formats, it is ideal for use in clinical, pharmaceutical, and environmental microbiology laboratories.
- Pack Size: 20/Box 100/Box