Hugh Leifson test
The Hugh-Leifson test , also known as the oxidation-fermentation test or OF-test , is used in microbiology to examine bacteria for their ability to form acid from carbohydrates under oxic and anoxic culture conditions. This allows conclusions to be drawn as to whether they break down carbohydrates oxidatively or fermentatively . These in turn are characteristic features of different bacteria and are therefore used to differentiate and identify them.
For this purpose, the microorganisms are cultivated in a high- layer agar tube which contains a pH indicator such as bromothymol blue . Bromthymol blue changes its color when acid is formed , which means that acid formation can be determined. In addition, with the help of a paraffin seal, growth can be shown in the absence of oxygen, i.e. anaerobic lifestyle. In the case of aerobes , no growth would take place in a tube sealed airtight with paraffin due to the lack of oxygen, unless they are facultatively anaerobic. If necessary, gas formation can be detected through the paraffin seal in that the gas formed collects between the agar medium and the paraffin plug.
The test was first described in 1953 by Rudolph Hugh and Einar Leifson , after whom it was named.
swell
- ^ R. Hugh, E. Leifson: The taxonomic significance of fermentative versus oxidative metabolism of carbohydrates by various gram-negative bacteria. In: J. Bacteriol. Vol. 66, 1953, pp. 24-26. PMID 13069461 .