Voges–Proskauer/ˈfoʊɡəsˈprɒskaʊ.ər/ or VP is a test used to detect acetoin in a bacterial broth culture. The test is performed by adding alpha-naphthol and potassium hydroxide to the Voges-Proskauer broth, which is a glucose-phosphate broth that has been inoculated with bacteria. A cherry red color indicates a positive result, while a yellow-brown color indicates a negative result.[1]
Two bacterial broth cultures, showing a positive result (left side) and a negative result (right side) for the VP test.
The test depends on the digestion of glucose to acetylmethylcarbinol. In the presence of oxygen and strong base, the acetylmethylcarbinol is oxidized to diacetyl, which then reacts with guanidine compounds commonly found in the peptone medium of the broth. Alpha-naphthol acts as a color enhancer, but the color change to red can occur without it.
Procedure: First, add the alpha-naphthol; then, add the potassium hydroxide. A reversal in the order of the reagents being added may result in a weak-positive or false-negative reaction.
VP is one of the four tests of the IMViC series, which tests for evidence of an enteric bacterium. The other three tests include: the indole test [I], the methyl red test [M], and the citrate test [C].[2]
^MacFaddin, J. F. 1980. Biochemical Tests for Identification of Medical Bacteria, 2nd ed. Williams and Wilkins, Baltimore
^Bachoon, Dave S., and Wendy A. Dustman. Microbiology Laboratory Manual. Ed. Michael Stranz. Mason, OH: Cengage Learning, 2008. Exercise 15, "Normal Flora of the Intestinal Tract" Print.
^ abBergey's Manual of Systematic Bacteriology, Vol. 1. Baltimore, Williams and Wilkins, 1984.
Voges–Proskauer (VP) Test- Principle, Reagents, Procedure and Result
April 11, 2024
voges, proskauer, test, voges, proskauer, test, used, detect, acetoin, bacterial, broth, culture, test, performed, adding, alpha, naphthol, potassium, hydroxide, voges, proskauer, broth, which, glucose, phosphate, broth, that, been, inoculated, with, bacteria,. Voges Proskauer ˈ f oʊ ɡ e s ˈ p r ɒ s k aʊ er or VP is a test used to detect acetoin in a bacterial broth culture The test is performed by adding alpha naphthol and potassium hydroxide to the Voges Proskauer broth which is a glucose phosphate broth that has been inoculated with bacteria A cherry red color indicates a positive result while a yellow brown color indicates a negative result 1 Enterobacter cloacaeProteus myxofaciensTwo bacterial broth cultures showing a positive result left side and a negative result right side for the VP test The test depends on the digestion of glucose to acetylmethylcarbinol In the presence of oxygen and strong base the acetylmethylcarbinol is oxidized to diacetyl which then reacts with guanidine compounds commonly found in the peptone medium of the broth Alpha naphthol acts as a color enhancer but the color change to red can occur without it Procedure First add the alpha naphthol then add the potassium hydroxide A reversal in the order of the reagents being added may result in a weak positive or false negative reaction VP is one of the four tests of the IMViC series which tests for evidence of an enteric bacterium The other three tests include the indole test I the methyl red test M and the citrate test C 2 VP positive organisms include Enterobacter Klebsiella Serratia marcescens Hafnia alvei Vibrio cholerae biotype El Tor and Vibrio alginolyticus 3 VP negative organisms include Citrobacter sp Shigella Yersinia Edwardsiella Salmonella Vibrio furnissii Vibrio fluvialis Vibrio vulnificus and Vibrio parahaemolyticus 3 History editThe reaction was developed by Daniel Wilhelm Otto Voges and Bernhard Proskauer German bacteriologists in 1898 at the Institute for Infectious Diseases References edit MacFaddin J F 1980 Biochemical Tests for Identification of Medical Bacteria 2nd ed Williams and Wilkins Baltimore Bachoon Dave S and Wendy A Dustman Microbiology Laboratory Manual Ed Michael Stranz Mason OH Cengage Learning 2008 Exercise 15 Normal Flora of the Intestinal Tract Print a b Bergey s Manual of Systematic Bacteriology Vol 1 Baltimore Williams and Wilkins 1984 External links editVoges Proskauer reaction at Merriam Webster Online Voges Proskauer VP Test Principle Reagents Procedure and Result Retrieved from https en wikipedia org w index php title Voges Proskauer test amp oldid 1131387015, wikipedia, wiki, book, books, library,
