Bolton Selective Enrichment Broth

Bolton Selective Enrichment Broth

Selective Enrichment Medium for Thermotolerant Campylobacter spp.
Catalog Number: AS-1146

Overview

Bolton Selective Enrichment Broth (CAT: AS-1146) is the internationally recognised reference medium for the selective enrichment of thermotolerant Campylobacter species, including C. jejuni, C. coli, C. lari, and C. upsaliensis, from foods, animal faeces, and environmental samples.

This medium is the mandatory enrichment broth specified in ISO 10272-1:2017, FDA-BAM Chapter 7, and USDA-FSIS methods. Its formulation combines a rich nutrient base, haematinised (lysed) blood, and a four-antibiotic selective supplement to ensure excellent recovery of stressed or low-level Campylobacter while strongly suppressing competing background flora.

Key Features & Benefits

• Official reference enrichment broth in ISO 10272-1:2017

• Optimised for thermotolerant Campylobacter spp.

• Haematinised blood + pyruvate support resuscitation of injured cells

• Four-antibiotic supplement ensures high selectivity

• Designed for microaerobic incubation at 41.5 °C

• Excellent performance with heavily contaminated food matrices

Typical Applications

Food Microbiology

• Detection of Campylobacter in poultry, meat, milk, and ready-to-eat foods

• Regulatory and quality-control testing laboratories

Clinical & Veterinary Microbiology

• Enrichment from faeces and clinical specimens with high background flora

Environmental Testing

• Recovery of Campylobacter from water and environmental samples

Reference Methods

• ISO 10272-1 (all parts)

• FDA-BAM Chapter 7

• USDA-FSIS Campylobacter protocols

Principle of the Medium

Bolton Broth provides a highly nutritive and protective environment that supports the recovery of stressed Campylobacter cells. Sodium pyruvate, α-ketoglutarate, and haematinised blood neutralise toxic oxygen radicals, while the selective antibiotic combination suppresses Gram-positive bacteria, Enterobacteriaceae, yeasts, and moulds. Incubation under microaerobic conditions at elevated temperature selectively favours thermotolerant Campylobacter species.

Composition (per litre – base only)

• Meat Peptone: 10.0 g

• Lactalbumin Hydrolysate: 5.0 g

• Yeast Extract: 5.0 g

• Sodium Chloride: 5.0 g

• Sodium Pyruvate: 0.5 g

• Sodium Metabisulfite: 0.5 g

• α-Ketoglutaric Acid: 1.0 g

• Haematinised (lysed) horse blood: 50 mL

Final pH: 7.4 ± 0.2 at 25 °C

Antibiotic Supplement (Bolton Selective Supplement)

Added after sterilisation and cooling:

• Vancomycin: 20 mg

• Trimethoprim: 20 mg

• Cefoperazone: 20 mg

• Amphotericin B (or Cycloheximide): 10 mg

(One vial per 500 mL or 1 L, depending on supplier specification.)

Preparation

1. Suspend 27.0 g Bolton Broth Base in 950 mL purified water

2. Autoclave at 121 °C for 15 minutes

3. Cool to 45–50 °C

4. Add 50 mL sterile lysed horse blood

5. Aseptically add reconstituted Bolton Selective Supplement

6. Mix gently and dispense 10–25 mL into sterile containers

Incubation

• 37 °C for 4–6 hours (pre-enrichment)

• Then 41.5 °C to a total of 40–44 hours

• Atmosphere: Microaerobic (≈5% O₂, 10% CO₂, 85% N₂)

Subculture

After 44 ± 4 hours, subculture onto selective agar such as:

• mCCDA

• Karmali Agar

Storage & Stability

• Dehydrated base: Store below 30 °C, dry and protected from light

• Prepared broth (with blood): Store at 2–8 °C, use within 24 hours

Intended Use

For laboratory food, clinical, veterinary, and environmental microbiology use only.
Not intended for human or animal therapeutic use.

Quality & Compliance

• Conforms to ISO 10272-1:2017 requirements

• Suitable for regulated and accredited laboratories

• COA, SDS, and TDS available upon request