universe84a

Introduction of MR Test MR test stands for Methyl Red test. It is used for enteric gram-negative rods, as part of identification to species level. MR test positive bacteria are Escherichia coli, Klebsiella ozanae, Klebsiella rhinoscleromatis while negative are  Klebsiella pneumoniae, Enterobacter species, etc. Principle of MR Test The methyl red (MR) test is used to determine if an organism is able to produce stable acid end products from glucose fermentation Methyl red indicator (red color below pH 4.4; yellow color...

VP Test VP Test stands for Voges Proskauer  test. It is applied for identification to the species level of the following groups of organisms-enteric gram-negative rods, Aeromonas, and Vibrio, viridans group streptococci, and staphylococci. Principle of VP Test Organisms utilizing the butylene glycol pathway produce acetylmethylcarbinol (acetoin) and butanediol, neutral end products that raise the pH towards neutrality (pH 6) and result in a high final pH. Most Enterobacteriaceae demonstrate one or the other metabolic pathway but...

Introduction of Quellung Reaction The quellung reaction is the swelling of the capsule and it is also called or Neufeld reaction which is the gold standard technique for serotyping pneumococcus and this quellung reaction was first described in 1902 by the scientist Fred Neufeld who applied this test only to Streptococcus pneumoniae. Capsular serotyping of the individual strains of S. pneumoniae is performed by the microscopic “precipitin test. This reaction is also applicable in the bacterial...