1. Chemical Antimicrobial Agents: Antibiotics
Vocabulary:
Antibiotics vs. chemotherapeutic agents
bacteriostatic vs. bactericidal
Commonly used antibiotics: Penicillin, Ampicillin, Tetracycline, Vancomycin, Ciprofloxacin
Agar Disk Diffusion Test or Kirby-Bauer Antimicrobial Susceptibility Test
Mueller-Hinton (MH) agar

2. Fleming and the Discovery of Penicillin
1928 mold grows on Staphylococcus aureus plate
Mold is named Penicillium notatum
Florey and Chain isolated Penicillin 10 years later – received Nobel prize
Alexander Fleming is originally from Scotland, but received his medical education at St. Mary’s Hospital Medical School in London.  He later became a professor of bacteriology in that same school.  The earlier of his two noteworthy discoveries was of the bacterial fighting properties of lysozymes, enzymes found in nasal secretions and other bodily fluids.  His inability to produce a concentrated form of lysozyme prevented it from being more successful (Cambridge 271).  But this was not Fleming’s most significant and memorable contribution to medicine.  In 1928, while working with cultured staphtlococcus bacteria, one of Fleming’s plates was contaminated with mold.  However, this contamination proved beneficial, since the mold actually killed the bacteria with which it had contact, thus demonstrating its bactericidal qualities.  Fleming cultured the mold and began performing additional experiments with it.  He found it to be harmless to animals but destructive to many disease-causing microorganisms, including staphylococcus, streptococcus, meningococcus and gonococcus (One Hund. Books 96).  The mold was named penicillium notatum, better known as penicillin. 
Fleming was not a chemist, and the lack of knowledge in this field hampered the success of penicillin for over a decade, since the drug was unstable and unpredictable in its existing form.  However, in 1940, Ernst Chain and Howard Florey of Oxford were able to make the necessary chemical alterations.  Within the next few years, knowledge of the drug spread, and the possibility of its usefulness in World War II prompted its production by large-scale manufacturers (Dict. Sci. Biog., Vol. 5 & 6, p. 30).  In 1945, Fleming, Chain and Florey shared a Nobel Prize for the discovery of this life-saving medication.

3. How to streak for confluent growth
Mark the bottom of your plate with a line. This will be your #1 position.

4. Rotate 60º clockwise

5. Rotate 30º clockwise

6. Our pattern:

7. Each student tests all available antibiotics for one bacterial species
Day 1
Materials needed per student:
One Petri plate containing Mueller-Hinton (MH) agar
One of the four bacterial species assigned per table
Sterile cotton swab
Materials needed per table:
One 0.5 McFarland standard (contains ~ 1.5 x 108 CFU/ml)
Four sterile saline tubes
Four 1 ml sterile pipettes
Five single disk dispensers plus five cartridges of antibiotic disks (P, AM, T, VA, CIP).
One each of the following pure cultures:
E.coli ATCC: 25922
S. aureus ATCC 25923
P. aeruginosa,
S. marcescens
Materials needed per team of two:
Laminated white card with black lines
Bunsen burner, inoculating loop
Each student tests all available antibiotics for one bacterial species