Thermo Scientific™ Oxoid™ Mueller Hinton Broth (Dehydrated)

Mueller Hinton Broth is a widely recognized medium used in antimicrobial susceptibility testing, specifically for broth dilution Minimum Inhibitory Concentration (MIC) studies. It shares the same nutrient formulation as Mueller-Hinton Agar (CM0337), ensuring consistency in testing.

Key Features:

• Nutrient Composition:
  • Beef infusion (300.0 g/L), casein hydrolysate (17.5 g/L), and starch (1.5 g/L).
  • pH: 7.3 ± 0.1 @ 25°C.
• Cation Adjustment: Requires supplementation with Mg²⁺ (10–12.5 mg/L) and Ca²⁺ (20–25 mg/L) after sterilization for accurate MIC determination.
• Applications:
  • Antimicrobial susceptibility testing.
  • MIC studies for sulfonamides and trimethoprim (with lysed horse blood or thymidine phosphorylase).
  • MIC determination for Helicobacter pylori in semi-solid agar format.

Preparation Instructions:

1. Weigh: Dissolve 21.0 g of dehydrated medium in 1 L of distilled water.
2. Sterilize: Autoclave at 121°C for 15 minutes.
3. Adjust Cation Levels: Supplement with Mg²⁺ and Ca²⁺ as per CLSI guidelines.
4. Store Prepared Medium: At 2–8°C.

Storage and Shelf Life:

• Dehydrated Medium: Store at 10–30°C, protected from moisture.
• Prepared Medium: Store at 2–8°C. Use before the expiry date.

Appearance:

• Dehydrated Medium: Straw-colored, free-flowing powder.
• Prepared Medium: Light straw to straw-colored solution.

Quality Control:

Special Considerations:

1. Performance Monitoring: Regularly verify performance using standard quality control organisms. Adjust Mg²⁺ and Ca²⁺ volumes if expected MIC values deviate.
2. Thymidine Content: Lower thymidine levels after adding lysed horse blood or thymidine phosphorylase for better MIC results.
3. Compatibility: Suitable for aerobic bacteria.

Applications:

• Used in standardized antimicrobial susceptibility testing.
• MIC determination in clinical, food, and pharmaceutical microbiology.
• Evaluation of fastidious organisms like Helicobacter pylori in semi-solid agar formats.

References:

1. NCCLS (2000) Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically.
2. Thornsberry et al. (1977) Cumitech 6, American Society for Microbiology.
3. Swenson & Thornsberry (1978) Curr. Microbiol.
4. Kobayashi et al. (1997) J. Antimicrob. Chemother.

This broth is an essential tool for laboratories conducting reliable and consistent antimicrobial susceptibility testing.