Seth Kinast’s Blog

Whew, had my micro lab tonight, with the first part of my lab practical. Easy stuff… we had to do a streak plate and a Gram stain. I can do plates in under a minute and stains in around 5. We got 35 minutes to do both. So the TA started the time and I took two or three minutes to do my plate because I wanted to make it extra nice. No problem. Then on to the stain…

Gram staining involves about six steps. I went ahead and prepared two in case one didn’t come out. First, grab some broth from the tube and spread it on the slide. Let air dry. Then, wave the slide over the burner to “fix” the bacteria to the slide. Stain with crystal violet, rinse. Stain with Gram’s iodine, rinse. Decolorize with etOH, rinse. Counterstain with saffarin, rinse. Mount under scope, done.

So I got the first slide done and popped in under the scope. Nothing was there. I decided I must not have fixed things well enough and then subsequently washed the culture off in the rinsing. I started my second slide when I noticed it wasn’t staining. Nothing there either. There were 15 minutes left.

I hurriedly pulled out two more slides. Inoculate, fix, stain, rinse… wait. These aren’t coming out either. What’s up!?

5 minutes. I only had time for one more slide. I COOKED that sucker, none of this wussy “wave-it-over-the-flame”. No bacteria were falling off of this one! The slide was so hot that when I poured crystal violet on it started to melt :/ so I had to rinse it off fast. Rinsed, counterstained, slammed it onto the scope with one minute left! And still nothing! But wait… there was a little pink smear on the edge. I switched to 40x magnification and saw a few dots. Switched to 100x oil immersion and finally! I saw bacteria. Hurriedly ID’d them and finished just as time was called.

We compared experiences out in the hall while grading was going on. Apparently most everyone had big problems. We decided that the broths were really diluted, and the TA is going to check on it.

Still stressful though