Introduction: Chemical methods of control: Antimicrobial drugs, involves the use of chemicals to prevent and treat infectious diseases. Pasteur and others observed that infecting an animal with Pseudomonas aeruginosa protected the animal against Bacillus anthracis. Later, the word “antibiosis” (against life) for this inhibition and called the inhibiting substance “Antibiotic”. As researchers found out more and more about these chemicals they were able to discover that antibiotics are chemicals or natural substances such as bacteria, fungi, as well as synthetic drugs; that inhibit or kill microbes in small amounts. Chemotherapeutic agents are antimicrobial chemicals (natural or synthetic) that can be used internally or may be absorbed.
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The antibiotics used were Bacitracin, Penicillin, Streptomycin, and Tetracycline. The antibacterial reaction as a whole relies upon the relationship between the cell wall and the antibiotic. The effectiveness of one antibiotic to another can be tested through a procedure called the Kirby-Bauer test. The test is administered to measure the degree of bacterial susceptibility to antibiotics using tablets of chemotherapeutic drugs and Mueller-Hinton agar plates, which allows the antimicrobial agent to diffuse freely.
*Table 1.0: Interpretation of Inhibition Zones of Test Cultures- look on lab manual page 143
Materials and Methods:
First Period materials:
-Petri plate containing Mueller-Hinton agar
- Sterile cotton swabs
- Dispenser and antimicrobial disks (Bacitracin, Penicillin, Streptomycin, and Tetracycline)
Second Period materials:
*The only culture used was the Escherichia coli broth
- Inoculating loop technique
- Aseptic technique
The procedure for this experiment was fairly simple. First make sure that proper sanitation and protection of the work area and experimenters have been done. Then proceed to taking the aseptically swab to the assigned culture onto the appropriate plate. Swab in three different directions (Starting at the top of the agar, swab back and forth across the plate. Then rotate it to a 45-degree angle and streaked again and once more afterwards) to make sure that