Published
I feel your pain. I had the same funk with my first unkown of the semester. I really worked my tail off. Our prof. gives us extra credit for correctly identifying the bacteria. We got points for running all the tests and correctly identifying the aspects of the test that she required.
After all the stress, I got my paper back this week and not only did I get all the experiements correct but I also got the extra point for IDing.
Whew! Just think how fun this would be if you were a research geek?
No, she didn't give us a chart. That's why I feel lost & overwhelmed! That with the added stress of being so far behind schedule already.
All I know is that it will be a Gram negative and I have to do a gram stain tomorrow to see if it's a rod or coccus.
That's all I know so far!! I feel so unprepared & I have an A in the class so it's not like I haven't been paying attention!!!
I know there are different tests to do but I'm just having trouble getting a clear picture in my head of what steps to take. Maybe the teacher will help me out a bit...... we shall see.
Have you tried to get notes from someone who copied what the instructor wrote one the board?
Do you have a list of bacteria it could be? If you do, then the best thing to do is to get a reference book of test results (should be one in the lab) and start making a chart of test results for each bacteria, then figure out which tests will rule the most candidates out and run those first. When we did ours, we were given a xerox of a one page chart of the most common bacteria and tests so we didn't have to look everything up in the book. Some textbooks have something like that in the back, but ours didn't.
If it's a gram negative rod there is a standard battery of diagnostic tests used to identify enteriobacteraciae (spelling?) called IMViC
-Indole
-Methyl Red
-Voges-proskauer
-Citrate
Here are some links that might be useful
http://web.indstate.edu/thcme/micro/g-neg.html
http://www.austincc.edu/microbugz/html/imvic_tests.html
For my group's gram - I think we did indole, methyl red, citrate, and urease, which was more than we needed to get a positive id for e. coli (our gram+ was much more stubborn)
One of the other groups threw every test we'd done in lab at their gram - and still didn't have an id until I suggested they do indole, which we had skipped in lab, that confirmed they had e. coli too.
My group had a little help because one of my friends is a clinical microbiologist, so I showed her my list of possibles and she suggested some general strategies.
One more tip - if you are allowed to use positive controls, run one with every test you haven't already done in regular lab. When we did indole (as SIM deeps), the indole reagent wasn't the same color as in the lab manual and so the positive result looked quite different. The other group with e. coli didn't think to run one, so they had to ask one of our group members to tell them if it was positive.
We just finished ours, and we had a chart in our book. Everybody got the full amount of points on it too. I had trouble at first because I was just looking at the IMViC series but I had a gram-postive rod and was not supposed to be referring to that chart. We also had a case study that we had to figure out which one went with our organism. Needless to say, I had Bacillus anthracis. My case study was about a cattle herder who wound up with a crusty black lesion on her ulna along with other symptoms. It was very tedious but even if we had got the wrong answer we still had an oppurtunity to find the right answer. :nuke:
I just got home from lab & my teacher was very helpful. Actually about 1/2 of the class was still in there stuggling (not just me!!!).
She knew that we were running out of time & told us what to inoculate next.
I will go to a different lab on Friday so I can read the results & see what to do next. Yahoo!
I have a gram negative rod so the info provided in this post is a great help. Thanks everyone.
arabmagic
55 Posts
Can I just say UGGGGG?
We are 1/2 way through the project, and I *thought* I had mine identified. Well now it appears that one of mine was contaminated and I have to start all over!!!!!
A lot of people in my lab are already done! I, on the other hand, have to go to an extra lab this week to try & catch up! Not only that, when the instructor was writing various notes on the boards this last week (ie. if it's Gram - , do this.... Gram +, etc.) I didn't copy any of that down because I didn't think I'd need it!
If anyone knows of any good websites with flow charts or helpful tips, that would be great! I am going to sit down now and make notes from our lab book of the different tests & results, etc.
I just hope the rest of this week goes smoothly! I was SO disappointed after class this evening.