Methyl Red Vice President (MR-VP) Broth 10mL Tube, 10/Pk

Methyl Red-Voges Proskauer (MR-VP) Broth is a dual-purpose medium used for the differentiation of bacteria, specifically within the Enterobacteriaceae family (coliforms). This single broth can be split to perform two distinct biochemical tests—the Methyl Red (MR) test and the Voges-Proskauer (VP) test—which aid in identifying genera like E. coli, Enterobacter, and Klebsiella.

Each tube contains 10mL of buffered peptone-glucose broth. After incubation (usually 48 hours), the broth is aliquoted into two separate tubes for testing:

1. Methyl Red (MR) Test: Detects stable acid production from glucose fermentation.

   • Add: Methyl Red pH indicator.

   • Positive (Red): Indicates mixed acid fermentation (pH < 4.4), typical of E. coli and Proteus.

   • Negative (Yellow): Indicates higher pH, typical of Enterobacter and Klebsiella.

2. Voges-Proskauer (VP) Test: Detects the production of acetoin (a neutral fermentation intermediate).

   • Add: Barritt’s Reagents A (alpha-naphthol) and B (KOH).

   • Positive (Red Ring/Color): Indicates the presence of acetoin, typical of Enterobacter and Klebsiella.

   • Negative (No Color Change/Copper): No acetoin produced.

Because these metabolic pathways are usually mutually exclusive, organisms are typically MR+/VP- (like E. coli) or MR-/VP+ (like Enterobacter aerogenes), making this a definitive diagnostic tool.

• Dual Diagnostic: One broth performs two critical IMViC identification tests.

• Differentiation: Clearly distinguishes E. coli from Enterobacter-Klebsiella group.

• Standard Formulation: Buffered glucose peptone broth ensures accurate pH changes.

• Versatile: Can be used for standard qualitative testing or quantitative studies.

• Format: Sterile 10mL tubes in a 10-pack.

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