Microbiology is coming along fairly well. I just finished my third lecture test, and I’m waiting to go into lab. Our unknown projects are due tomorrow. I was a little apprehensive going into this project, but I’ve had a lot of fun. I don’t know if other schools set up the microbiology unknown projects the same way, but this is how ours works:
We are each given two different specimens in a broth culture. All we know is that we have one Gram positive and one Gram negative. We have to get pure, isolated cultures of each, and properly identify each organism.
My first TSA streak plates didn’t go well, but I did have some growth on both my EMB and blood/PEA plates. These were a big help to narrow down which specimen was Gram positive and which was Gram negative. Gram staining is so tricky!
After isolating my Gram negative specimen, I started running tests on it. The glucose test came back positive: bright yellow, with gas in the vial. The lactose test was also positive with the top of the tube red and the bottom yellow. With these results, I decided to use the citrate and indole tests. In the citrate test, the slant was a bright, Prussian blue — positive! The negative indole test confirmed my results. A positive result on my Voges Proskauer test eliminated a couple possibilities, and I decided my Gram negative bacillus is Enterobacter aerogenes. I ran a few other tests (ornithine, phenylalanine, nitrate, TSI and urea) to confirm my results. So far, all the test results are in line with what is expected of Enterobacter aerogenes.
I made a mistake with my Gram positive specimen, so I had to rerun a test overnight. As of now, I know I have Gram positive cocci. It bubbled like crazy during the catalase test, and it is glucose negative (red) with no gas. I tried to run the nitrate test, but I got a little impatient. I only waited about a minute after putting in the Nitrate I and II drops before I added the zinc. I got a reaction! But, since my Gram positive specimen is such a slow grower, I should have waited a full three minutes. I suspect I have Sarcina lutea (which means it reacted to the zinc, and has NO3-, but I’m not sure. If the reaction was due to the Nitrate I and II drops, then I have Micrococcus luteus. I’m fairly sure I have Sarcina lutea, and will confirm soon.
What a way to spend a summer, hmm?
Alliance of Free Blogs - I found You Know You Wanna while searching for kitty porn. No, that's not a typo.
So when can I expect you to grow the mutant monkey butlers I ordered?
All sounds way to complex for me
Comment by Tars — June 28, 2007 @ 12:31 pm
(Admits in a geeky way: Yes, it does sound like a cool way to spend summer!) Micro was a lot of work, but I did it in the fall. You’re brave to tackle it in the summer session!
Comment by StudentNurseJack — July 11, 2007 @ 10:10 pm
Hi, I’m just finishing up my bachelor’s degree and am planning on going to nursing school next year. I think you said you have a dog? I was thinking about getting one, and I was just wondering how you balance nursing school and your pup. Thanks!
Comment by Sarah — July 17, 2007 @ 12:06 pm
Ok, I really feel that I got the shaft w/ micro because I did not get identify organisms. The most fun I had was swabbing my own armpit to see what would grow. How lame? I didn’t even get to identify my own filth. So enjoy it while you can.
Comment by C — August 5, 2007 @ 10:32 pm
My unknown was Bacillus Strobillus, micro was such a fun class. Where do you go to school?
Comment by AlmostNursingStudent — January 4, 2008 @ 2:24 am
Good post. You make some great points that most people do not fully understand.
“Microbiology is coming along fairly well. I just finished my third lecture test, and I’m waiting to go into lab. Our unknown projects are due tomorrow. I was a little apprehensive going into this project, but I’ve had a lot of fun.”
I like how you explained that. Very helpful. Thanks.
Comment by chiz — February 19, 2008 @ 1:47 pm