Day 2 -Cultures, Smear Plates, and Broth Innoculations

This bunsen burner is ready to go for a brand new day of lab. Are you?

Today we learned how to do a streak plate and inoculate bacteria into a broth culture, after examining the cultures from yesterday. According to the incubated yesterday's, we managed to grow a lot of colonies. We also learned how to examine the growth patterns of bacteria by determining the characteristic features of a colony's form, pigmentation, margin, and elevation. Using aseptic techniques, we left the lab as clean as we found it, ready for a new day of microbiology tomorrow at 8:15.

We entered the lab today, and following procedure we all donned our lab coats, washed our hands, and sprayed the lab bench with lysol. Following this preliminary cleaning, microbiology class 2012 opened the incubator to find that our hands are not as clean as they appear; most of us had bacteria with slime excretions hangin' out on our skin.

After this, streak plates were the next line of business. In this process, we drew out the streak pattern we were going to follow, and after sterilizing the loop, we picked up some bacteria from my throat culture, and began isolating it by slowly draging it across the surface of our agar petri dish, like so,

Streak Plate Design

After each streak, the loop was sterilized and the bacteria spread out more and more until, hopefully on streak 3, each type of bacteria is isolated.

Then came our sample bacteria from Dr. Joseph. First we sterilized the loop, took off the cap of the agar tilt sample, waved the top of the test tube through the flame of the bunsen burner, and (after hitting the loop against the sides of the test tube to cool it off a little) picked up a colony of bacteria, and returned the cap of the agar test tube after waving it again through the flame. Then, taking the cap off the sterile broth, waving its top through the flame, we used the loop to deposit the bacteria into the broth. After taking the loop out, waving the opening over the bunsen burner, and returning the cap, we wait until tomorrow to seek the fruits...or not so fruity results of our labor.

A close up view of the two bacteria on the back of Grace's throat.
These particular bacteria were both raised, cirucular, cream-colored colonies, with a glistening body, and an 'entire' edge.

Using aseptic technique, all the microorganisms on the loop are killed- sterilizing it for use as a bacterial transport into the broth culture

Our completed streak plate, ready to be put in the incubator.

Our super-cool pink bacteria ready for dinner in the broth!!!

* App of the day - The way that these streak plates are done is the same procedure that they will do in the hospitals. There are thousands of bacteria living on us every day. To determine which one is causing the problem, we have to perform certain measures to isolate the bad from the good.