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GN Broth, Hajna | Enrichment Medium for Enteric Bacteria | AS‑1244
$40.00 AUD
AuSaMicS Life Science • Enteric Enrichment Media
GN Broth, Hajna
Selective Enrichment Broth for Salmonella, Shigella & Other Gram-Negative Enterics
GN Broth, Hajna is a selective enrichment medium developed for the recovery of gram-negative enteric pathogens, particularly Salmonella and Shigella, from clinical and non-clinical specimens before plating onto selective agar. Its balanced formulation suppresses much competing flora while allowing target enteric pathogens to multiply during the enrichment phase. :contentReference[oaicite:1]{index=1}
AS-1244 pH 7.0 ± 0.2 ✓ Australian Stock 🧫 Enteric Enrichment 🛡️ Selective Recovery
Targets: Salmonella & Shigella Subculture: 6–8 h and 24 h Documents: COA + SDS + TDS
Why Labs Use Hajna GN Broth
Selective enrichment before plating
Citrate + deoxycholate suppress competitors
Mannitol bias helps control Proteus overgrowth
Clinical & food use positioning
Established classical medium in enteric workflows
Enrichment Logic
Inoculate specimen
Enrich target enterics
Subculture to selective agar
Confirm suspect colonies
Enrich target enterics
Subculture to selective agar
Confirm suspect colonies
⚠️ Important: GN Broth is an Enrichment Step — Not a Final Identification Medium
What GN Broth does
It selectively enriches enteric pathogens such as Salmonella and Shigella from mixed specimens before plating to solid media. Published instructions recommend subculturing after 6–8 hours and again after 24 hours. :contentReference[oaicite:2]{index=2}
It selectively enriches enteric pathogens such as Salmonella and Shigella from mixed specimens before plating to solid media. Published instructions recommend subculturing after 6–8 hours and again after 24 hours. :contentReference[oaicite:2]{index=2}
What GN Broth does not replace
Further isolation on selective/non-selective agar and biochemical or other confirmatory testing are still required for final identification. :contentReference[oaicite:3]{index=3}
Further isolation on selective/non-selective agar and biochemical or other confirmatory testing are still required for final identification. :contentReference[oaicite:3]{index=3}
🔬 Technical Overview & Principle
GN Broth was developed by Hajna as an enrichment medium for the isolation of enteric gram-negative bacilli. Product literature specifically highlights recovery of Salmonella and Shigella from clinical and non-clinical materials such as rectal swabs, faeces, urine, blood clots, throat swabs, utensils, and food-related samples. It is also noted as recommended by APHA for food microbiology use. :contentReference[oaicite:4]{index=4}
Selective inhibition system
Sodium citrate and sodium deoxycholate suppress gram-positive organisms and some competing gram-negative flora such as coliforms, improving relative recovery of target enteric pathogens. :contentReference[oaicite:5]{index=5}
Sodium citrate and sodium deoxycholate suppress gram-positive organisms and some competing gram-negative flora such as coliforms, improving relative recovery of target enteric pathogens. :contentReference[oaicite:5]{index=5}
Mannitol-dominant carbohydrate balance
Published descriptions note that the higher mannitol concentration relative to dextrose helps limit Proteus overgrowth while enhancing the growth of mannitol-fermenting Salmonella and Shigella. :contentReference[oaicite:6]{index=6}
Published descriptions note that the higher mannitol concentration relative to dextrose helps limit Proteus overgrowth while enhancing the growth of mannitol-fermenting Salmonella and Shigella. :contentReference[oaicite:6]{index=6}
Mixed enteric specimen
↓
GN Broth enrichment step
↓ (citrate + deoxycholate suppress competitors)
Salmonella / Shigella enrichment
↓
Subculture to selective agar at 6–8 h and 24 h
↓
Presumptive colony isolation for confirmation
↓
GN Broth enrichment step
↓ (citrate + deoxycholate suppress competitors)
Salmonella / Shigella enrichment
↓
Subculture to selective agar at 6–8 h and 24 h
↓
Presumptive colony isolation for confirmation
Practical advantage: product literature notes that Proteus, Pseudomonas, and coliforms do not overgrow Salmonella and Shigella during the first 6 hours of incubation, which is one of the key reasons this broth is useful as an early enrichment step. :contentReference[oaicite:7]{index=7}
🧪 Standard Composition Table
🧫 Typical Enrichment Workflow
1
Prepare and dispense the broth
Published directions specify 39.0 g/L with sterilisation at 115°C for 15 minutes, while avoiding excessive heating. :contentReference[oaicite:17]{index=17}
Published directions specify 39.0 g/L with sterilisation at 115°C for 15 minutes, while avoiding excessive heating. :contentReference[oaicite:17]{index=17}
2
Inoculate directly with specimen
The broth is intended for direct inoculation with clinical or non-clinical specimens; published guidance notes about 1 g of stool specimen can be used where appropriate. :contentReference[oaicite:18]{index=18}
The broth is intended for direct inoculation with clinical or non-clinical specimens; published guidance notes about 1 g of stool specimen can be used where appropriate. :contentReference[oaicite:18]{index=18}
3
Incubate and subculture at two time points
Subculture onto selective agar after 6–8 hours and again after 24 hours to improve the probability of recovering enteric pathogens. :contentReference[oaicite:19]{index=19}
Subculture onto selective agar after 6–8 hours and again after 24 hours to improve the probability of recovering enteric pathogens. :contentReference[oaicite:19]{index=19}
4
Confirm suspect isolates
Use the enrichment broth together with selective and non-selective plating media and follow with confirmatory testing as required by the method. :contentReference[oaicite:20]{index=20}
Use the enrichment broth together with selective and non-selective plating media and follow with confirmatory testing as required by the method. :contentReference[oaicite:20]{index=20}
📊 Comparative Enteric Enrichment Media
📌 Quick Specifications
Product: GN Broth, Hajna
Cat. No.: AS-1244
Format: Dehydrated culture medium
Type: Selective enrichment broth
Main targets: Salmonella, Shigella
Typical specimens: stool, rectal swabs, urine, food and related samples
Follow-up: selective agar subculture
Storage: 10–25°C, dry, tightly closed, protected from moisture and light
⭐ Key Advantages
✓Selective enrichment before plating improves pathogen recovery probability
✓Classical medium for Salmonella and Shigella workflows
✓Useful in both clinical and food microbiology contexts
✓Balanced formula reduces overgrowth by competing flora during early enrichment
✓Compatible with downstream selective and non-selective agar workflows
⚙️ Preparation Notes
Published directions specify suspending 39.0 g in 1 L purified or distilled water. :contentReference[oaicite:24]{index=24}
Sterilise at 115°C for 15 minutes and avoid excessive heating. :contentReference[oaicite:25]{index=25}
Use according to your validated enteric enrichment protocol and always follow with appropriate plating and confirmation steps. :contentReference[oaicite:26]{index=26}
🔗 Related AuSaMicS Products
Hektoen Enteric Agar
Selective/differential agar for presumptive Salmonella and Shigella colony screening
MacConkey Agar
Common downstream plating medium for enteric gram-negative differentiation
Other enteric enrichment broths
Complementary enrichment options for method-specific pathogen recovery workflows
Reliable Enteric Enrichment Before Selective Plating
AuSaMicS supplies high-quality microbiological media designed for dependable performance in clinical, food, and industrial laboratories. Contact us for technical documentation, bulk supply, or workflow-aligned support for enteric pathogen recovery.
For laboratory, research, and industrial use only. Not for food, feed, household, cosmetic, therapeutic, or personal use.
AuSaMicS Pty Ltd • ABN 56 676 640 467 • 31 Longview CT, Thomastown, VIC 3074, Australia
www.ausamics.com.au • support@ausamics.com • +61 412 520 598