Microbiology Tech Info

  Aim This test is used to differentiate of Enterobacteriaceae based on their ability to use citrate as the sole carbon source. Principle Sodium citrate is a salt of citric acid, a simple organic compound found as one of the metabolites in the tricarboxylic acid cycle (Krebs cycle). Some bacteria can obtain energy in a manner other than by the fermentation of carbohydrates by using citrate as the sole source of carbon. The measurement of this characteristic is important in the identification of many members of the Enterobacteriaceae. Any medium used to detect citrate utilization by test bacteria must be devoid of protein and carbohydrates as sources of carbon. The utilization of citrate by a test bacterium is detected in citrate medium by the production of alkaline by-products. The medium includes sodium citrate, an anion, as the sole source of carbon, and ammonium phosphate as the sole source of nitrogen. Bacteria that can use citrate can also extract nitrogen from the ammon...