Question

can you please answer all the questions

You have been given another unknown and the Gram stain results revealed Gram positive rods. Your TA now tells you that you should inoculate your unknown into a TSB broth to be incubated at 65 degrees C for 24 hr. and to streak it onto a TSA plate for isolation. The TSA plate is incubated at 35-37 degrees C for 24 hr. It will then be used to do further inoculations of your unknown. Use the unknown tables and your notes to answer the following questions. You observed the 65 degree TSB and found it to be clear. What organism(s) cannot be considered based on this test? 0.25 point What special stains would you do to help identify your organism? 0.25 point An acid-fast stain is done on an isolated colony from the TSA plate and it is negative. At this point what organism(s) are to be eliminated and still considered as your unknown? 0.25 point You now perform the following tests with these results: Indicate what the reaction is next to each test (positive or negative) Nitrate = no color change (after adding reagents A& B), color change to red after adding zinc dust 0.25 point Methyl Red = yellow 0.25 point Citrate = you observe a bright (Prussian) blue color 0.25 point What is your unknown? 0.5 point Construct a flow chart using the information from above: 0.5 point 2019

Answer 1

Ans 1: TSB broth is used as a culture broth to grow aerobic bacteria and facultative anaerobes and since the broth is found to be clear we can say that the unknown is not aerobic or facultative anaerobe in nature.

Ans 2: Gram stain is an important rapid tool for anaerobic bacteriology.

Ans 3: Acid fast staining is used to identify acid-fast organisms such as members of the genus Mycobacterium. Since our organism of interest is showing negative acid fast staining so all the members of mycobacterium genus are excluded and all the anaerobic non acid bacteria are included.

Ans 4: First methyl red takes place and the yellow color represents negative methyl red test.

Second Citrate test takes place and the bright blue color represents positive Citrate test.

Third Nitrate reduction test takes place and the red color represent positive nitrate reduction test.

Ans 5: From all the tests we will match it with the table that is not attached with the question and we will find out our unknown bacteria which should be gram +ve rod shaped and obligate anaerobic in nature showing the following characterstics described above.