A colleague of yours has produced a set of media that was in

A colleague of yours has produced a set of media that was inoculated with the same baderia. But due to poor labeling technique, they need hep in soMing the mystery. You have a kind nature so have offered to hep out this hapless colleague. Interpret the resut for each media (the results listed are comect, can be trusted, and nothing went wrong with the inoculation) wth the hep of the Gram tables atthe end of unt 13 n your lab manual, determine the organism\'s identity Use the following abbreviations for the eliminated organisms in each case. atrobacter freundli- Cf, Eschercha coli- Ec, Klebsela pneumoni Kp, Proteus vugars Pv be Pseudomonas aeruginosa Pa, Serrata marcescens. Sm, Shyela fexneri- Sf You must give a complete description of what the test resuts tell you and why!! This means you will need to note what you know about products, pH enzymes present etc for full credit Notice that in each case you must tell me which bacteria the results eliminate for that test only. That means you say \"if these resuts are accurate then this organism should not be Consider carefully the catabolism information and clearly interpret all results. Answers that simply state negative or positive without interpretaton of the resuts will not be considered. Be specific. Please turn in a neat and professional boking quiz.

Solution

1. Decarboxylase broth tests the production of the enzyme decarboxylase, which removes the carboxyl group from an amino acid. After you inoculate the decarboxylase broth but before you incubate the tubes, add an overlay of sterile mineral oil to each tube. If yellow color appears in the test tube with a layer of sterile mineral oil at the top, shows that the pH is acidic.

Interpretation: Each decarboxylase enzyme is specific to the amino acid it acts on. If the organism is unable to ferment dextrose, there will be no color change in the medium. If an organism is able to ferment the dextrose, acidic byproducts are formed, and the media turns yellow. As the organisms ferment the dextrose, the media initially turns yellow, even when it has been inoculated with a decarboxylase-positive organism. The low pH and the presence of the amino acid will cause the organism to begin decarboxylation.

If an organism is able to decarboxylate the amino acid present in the medium, alkaline byproducts are produced. Lysine decarboxylation results in cadaverine. These byproducts are sufficient to raise the pH of the media so that the broth turns purple.

If the lysine decarboxylase tube shows purple color, then the pH of the medium will be alkaline and if it shows yellow color, the pH is acidic. So, in this case the pH is acidic.

This test eliminates Proteus Vulgaris.