Determine the ability of an organism to reduce nitrate to nitrite or free nitrogen gas using Thermo Scientific™ Remel™ BactiDrop™ Nitrate Reagent A. This ability is characteristic of the Enterobacteriaceae1 family. Nonfermenters and other miscellaneous gram negative bacilli vary in their ability to reduce nitrates, with some being capable of further reducing nitrite to nitrogen gas2. In 1962, Daubner reported that all members of the Enterobactericeae tested, with the exception of Erwinia species, reduced nitrate in eight hours3.
Nitrate serves as a source of nitrogen for many bacteria and fungi, but in order to be utilized it must be broken down.Ready to use: Convenience of a prepared reagent.Ease of Differentiation: Positive test indicated by red color development after addition of reagents; and no color development after addition of zinc dust. Negative test indicated by no color development after addition of reagents and red color development after addition of zinc dust.Rapid Detection: Immediate results.The nitrite reduction test is a two-step procedure. Sulphanilic acid is added to acidify the medium and then naphthylamine is added which reacts with the nitrites to produce a red color. Certain bacteria convert nitrate to nitrite, ammonia, or gas. This process is denitrification. If no color develops after addition of reagents, the organism has either reduced the nitrate to free nitrogen or it has not attacked the nitrate at all. Nitrate will react with zinc dust to form nitrite. A pink to red color development after addition of zinc dust indicates that the nitrates are present and the test is negative. No formation of a red color after addition of zinc dust indicates that the organism has reduced the nitrate to free nitrogen or ammonia and is considered a positive nitrate test2.Used in conjunction with Nitrate Reagent B, Part No. R21538.Not all products are available for sale in all territories. Please inquire.Remel™ and Oxoid™ products are now part of the Thermo Scientific brand.
- Ewing, W.H. 1986. Edwards and Ewings identification of Enterobacteriaceae. 4th Elsevier, New York, NY.
- MacFaddin, J.F. 2000. Biochemical Tests For the Identification of Medical Bacteria. 3rd ed. Lippincott Williams & Wilkins, Philadelphia, PA.
- Daubner, I. 1962. Arch, Hyg. Berlin. 146:147-150.