Day 4 - How Antibiotics affect MRSA and Our Unknown Bacteria

This experiment is to show how different antibiotics affect MRSA and our unknown bacteria.

Materials:
Agar plate streaked with MRSA
Linezolid
Vancomycin
Ginger essential oil
Cinnamon essential oil
Oxacillin
Agar plate streaked with our unknown bacteria
Penicillin
Novobiocin
Neomycin
Tetracycline
Amoxycillin
Pipet
Bunsen burner
Forceps
Small beaker of alcohol

Steps:
1.  Sterilize the forceps by dipping them in alcohol and then burning off the alcohol.
2.  Take linezolid and place at the top of the MRSA agar plate.  Sterilize the forceps.
3.  Take vancomycin and place at the left of the MRSA agar plate.  Sterilize the forceps.
4.  Take ginger oil and place at the right of the MRSA agar plate.  Sterilize the forceps.
5.  Take cinnamon oil and place at the bottom of the MRSA agar plate.  Sterilize the forceps.
6.  Take 5 microliters of oxacillin in a pipet with a sterile, disposable end, and place it at the center of the MRSA agar plate.
7.  Incubate at 35 degrees for 24 hours.
8.  Take penicillin and place at the top of the MRSA agar plate.  Sterilize the forceps.
9.  Take novobiocin and place at the left of the MRSA agar plate.  Sterilize the forceps.
10.  Take neomycin and place at the right of the MRSA agar plate.  Sterilize the forceps.
11.  Take tetracycline and place at the bottom of the MRSA agar plate.  Sterilize the forceps.
12.  Take 5 microliters of amoxicillin and place in the middle of the MRSA agar plate. 
13.  Incubate at 35 degrees for 24 hours.
14.  Measure the diameter of the clear circles around the antibiotics.  This helps determine how effective the antibiotics are.


Results:

MRSA

MRSA

Our Unknown Bacteria

Diameters for MRSA:
Linezolid                         27 mm
Vancomycin                    10 mm
Ginger essential oil           8 mm
Cinnamon essential oil   19 mm
Oxycillin                          0 mm

Diameters for our unknown bacteria:
Penicillin     - 0 mm
Novobiocin - 15mm
Neomycin    - 0mm
Tetracycline - 18 mm
Amoxicillin - 11mm


Discussion:
For MRSA, we combined antibiotics and essential oils.  Our unknown bacteria will be tested with essential oils in the next experiment.
MRSA is sensitive to linezolid and cinnamon oil.  It is slightly sensitive to vancomycin and ginger oil.  It is resistant to oxycillin. 
Our unknown bacteria is sensitive to tetracycline.  It is also rather sensitive to novobiocin and amoxicillin.  It is resistant to penicillin and neomycin.