March 25, 2013
Bacterial Unknown Report
Each student was given an unknown bacteria to figure out. I was given the unknown bacteria S38. Everybody is supposed to do all sorts of test to identify the bacteria. The first thing I did was smear my bacteria on a liquid medium. I then proceeded to incubate the medium for 24-48 hours.
1. GRAM STAIN
The next step I took in finding my unknown bacteria was to gram stain it. This is used to differentiate the bacteria. The different staining reagents are: crystal violet, grams iodine, acetone-alcohol, and grams safranin. Under the microscope it was a pink color, which means Gram Negative. Also, the shape was a rod.
2. KLIGER’S IRON AGAR (KIA)
The next step I did was the KIA slant. This is for the Negative bacteria to see if they are in the Enteriobacteriaceae group. There are many different results than can occur, like: 1. Yellow slant/yellow deep- (A/A) glucose & lactose are fermented; if the butt has bubbles in it or is displaced, the tube is gas positive. 2. Red slant/yellow deep- (K/A) glucose but not lactose is fermented 3. Red slant/black deep- (K/A) glucose but not lactose is fermented and H2S2 is produced. The deep is acid (yellow) 4. Red slant/ red deep- (K/NC) neither carbohydrate is fermented. Peptone is degraded aerobically My result was a red slant and black deep. When is H2S2 is produced. The deep is acid (yellow). Glucose was fermented and lactose wasn’t.
3. UREASE HYDROLYSIS TEST
This test is used to see if urea is used. Proteus can be determined because there fast urease activity. Proteus is the ability to utilize lactose. My test resulted in a positive result. It was a pink color.
In my end result, my unknown bacteria is Proteus Vulgaris.
Positive Gram Stain|
Negative gram stain|
KIARed slant/black deep|