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What is antimicrobial agents?
Substances used to kill prokaryotes
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What produced antimicrobial agent?
Microbes
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What does antimicrobial include?
- All inclusive, anything that inhibits microbes
- Ex: amphyll, antibiotics
- Penicillin produced P. notatum (mold)
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What is an example of synthetic antimicrobial?
Amoxicillin made after naturally occuring penicillin
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What is antibiotic?
Natural substance that was produced by one microorganism to inhibit another mircoorganism
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What is narrow spectrum drug?
- Drug target a specific type of bacteria
- Ex: Gram positive or gram negative targeting only
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What is broad-spectrum antibiotics?
- Antibiotics that can kill off multiples types of microorganism
- Ex: both Gram positive and gram negative
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What is Bacteriostatic?
Prevents microbial growth
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What is MIC?
- Minimum Inhibitory Concentration: lowest antibiotic concentration that prevents bacterial growth
- Estimate using the E-test(E-epsilometer)
- Plastic strips with increasing (antibiotic)
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What type of drugs can inhibit peptidoglycan cell wall synthesis?
Penicillins, Bacitracin, Vancomycin, Cephalosporin
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Which drug inhibit protein synthesis?
Erythromycin, Tetracyclin, Streptomycin
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Which drugs inhibit nucleic acid replication?
- Limited used due to affecting euk. DNA
- Quinolones, Rifampin
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Which drugs injure plasma membrane?
- Polymyxin B
- Cause loss of essential metabolites from the cell
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Which drug inhibit essential metabolites synthesis?
- Sulfanilamide, Trimethoprim
- inhibit enzymatic reaction
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What is MRSA?
Methicillin-resistant Staphylococcus aureus
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Is methicillin-resistant Staphylococcus aureus more virulent than normal Staphylococcus aureus?
No, just harder to treat with normal antibiotic
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What is another name for disk diffusion method?
Kirby-Bauer Test
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What is E-test?
Epsilometer test, more advanced diffusion method
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Can E-test determine if a bacteria is bactericidal or bacteriostatic?
NO
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What is broth-dilution test?
Sequence of decreasing drug concentration in broth
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How do we determine if the drug is bactericidal or bacteriostatic?
Inoculate the last well with no growth of bacteria with the drug concentration. If there is growth on plate after inoculation, then the drug is bacteroistatic. If there is no growth, then the drug is bactericidal. You can find the concentration of the drug when it is either bacteriostatic or bactericidal
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What is the purpose of the Kirby-Bauer test(disk diffusion test)?
measure the effectiveness of antimicrobial drugs agains pathogen
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What affect the size of zone of Inhibition?
Sensitivity to the drug
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What happen when the drug has poorer solubility?
It has smaller zone of inhibition
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What is the standard length of the Mueller-Hinton agar and why?
4 mm agar depth, 100 mm or 150mm Petri dishes.
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What is in Mueller-Hinton agar?
- contain specific % of Barium Sulfate
- Produce turbidity and simulate growth
- Use test culture at the 0.5 McFarland (about 1.5X10^8
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