Health Dictionary
Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.
Nitrate reductase test
Introduction
The nitrate reductase test is a test to differentiate between bacteria based on their ability or inability to reduce nitrate (NO3) to nitrite (NO2) using anaerobic respiration.
Procedure:
- Inoculate nitrate broth with an isolate and incubate for 48 hours.
- Add 10-15 drops each of sulfanilic acid and N,N-dimethyl-1-naphthylamine. If the bacterium produces nitrate reductase, the broth will turn a deep red within 5 minutes at this step.
- If no color change is observed, then the result is inconclusive. Add a small amount of zinc to the broth. If the solution remains colorless, then both nitrate and nitrite reductase are present. If the solution turns red, nitrate reductase is not present.