bios242n_week6

Introduction As previous labs have demonstrated, utilizing various methods to test and determine bacteria types are invaluable to researchers, scientists and medical practitioners. By compiling data about these microorganisms, developments can be made to determine the most effective medicines for treating them. One such test to determine bacteria type, based on their metabolic waste, is the MR/VP test, or Methyl Red/Voges-Proskauer test and noting the reaction. Beyond determining bacteria types, another important aspect of classifying and understanding bacteria is knowing how they will respond to various antibiotics. Depending on the diameter of the zone of inhibition on agar dishes inoculated with various bacteria strains, we can determine if that strain is resistant, intermediate or susceptible to that antibiotic. This is obviously extremely useful when culturing and testing in medicine to choose the most appropriate course of treatment. Methods Methyl Red/Vogues-Proskauer Test For the MRVP test, four sterile test tubes were inoculated with E. coli, S. epidermidis, S. marcescens and B. cereus, respectively. These were left to incubate for 24 hours at 37 degrees celsius. At the end of 24 hours, the tubes were divided, 50/50, to allow for a separate MR and VP test for each strain. The tube openings were flamed before transfer, to ensure sterility. In four of the tubes, 6-8 drops of Methyl Red were added, with results available immediately. In the second set of four tubes to test for VP reaction, 12 drops of Barritt’s A Reagent were added, and the solution mixed gently. Then, four drops of Barritt’s B Reagent were added, and the tube again shaken gently