Pasteur
Observed that infecting an animal with Pseudomonas aeruginosa protected the animal against Bacillus anthracis
Antibiotic
A substance produced by a microorganism that inhibits other microorganisms
Alexander Fleming
Observed antibiosis around a penicillium mold growth on a culture of staphylococci
Selman Waksman
Isolated the antibiotic sterptomycin, produced by actinomycete
Stretomyces Bacteria
Produce nearly 70% of all antibiotics
Antimicrobial drugs
-chemical used internally
-weather natural or synthetic
Pathogen
Disease-causing organism
Disk-diffusion method
-Disk impregnated with various antimicrobial agents
-Agents diffuse during incubation
-Diffuses from area of high concentration to low
Zone of inhibition
-Are around disk that inhibits bacterial growth
-Zone size affected by diffusion rate and growth rate
Kirby-Bauer test
-standard test
-test for agar diffusion methods
-uses Mueller-Hinton agar
Minimum Inhibitory Concentration (MIC)
determined by testing for bacterial growth in dilutions of the antibiotic in nutrient broth
Zone of inhibition is measured in
Millimeters
Each filter disk placed on agar is impregnated with
Antibiotic
Agar used in the Kirby-Bauer test to test the effectiveness of antibiotics
Muller-Hinton agar plate
The paper disks have a symbol which represents________ and a number which represents___________
-Name of antibiotic
-The amount of antibiotic
The ________ of the zone of inhibition is measured to determine if an organism is susceptible or resistant to a particular antibiotic
Diameter
Plates used for disk diffusion method are inoculated with
a sterile cotton swab
Why is it important to tap the filter disk gently before incubating
To prevent it from falling off agar when u flip the plate for incubation and allowing it to stick