BIOL 220 Lecture Notes - Lecture 6: Gene Duplication, Antimicrobial Resistance, Cell Membrane
Lecture 6
BIO 220
Microbial Control and Antibiotics
The Golden Age of Antibiotic Discover
oAntibiotics are compounds produced by one microbe that adversely affect other
microbes
oThe modern antibiotic revolution began in 1928 with the discovery of penicillin by
Alexander Flemming
A contaminating mold had inhibited the growth of S. aureus colonies
oPenicillin was purified by Howard Florey and Ernest Chain
Antibiotic Classification
oBactericidal
Antibiotics kill target organisms
Many drugs only affect growing cells
Only effective if organism is building new cell wall
oBacteriostatic
Antibiotic prevents the growth of organisms
Cannot kill the organism
Immune system removes intruding microbes
Measuring Drug Susceptibility
oOne critical decision a clinician must make when treating an infection is which antibiotic
to prescribe for the patient
There are several factors to consider such as
The relative effectiveness of different antibiotics on the organism
causing the infection
The average attainable tissue levels of each drug
Minimal Inhibitory Concentration
oThe MIC is the lowest concentration that prevents growth
Varies for different bacterial species
Test by diluting antibiotics
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Document Summary
Microbial control and antibiotics: antibiotics are compounds produced by one microbe that adversely affect other microbes, the modern antibiotic revolution began in 1928 with the discovery of penicillin by. A contaminating mold had inhibited the growth of s. aureus colonies: penicillin was purified by howard florey and ernest chain. Only effective if organism is building new cell wall: bacteriostatic. Measuring drug susceptibility: one critical decision a clinician must make when treating an infection is which antibiotic to prescribe for the patient. There are several factors to consider such as. The relative effectiveness of different antibiotics on the organism causing the infection. The average attainable tissue levels of each drug. Minimal inhibitory concentration: the mic is the lowest concentration that prevents growth. May still have living but nongrowing organisms. Antibiotics exhibit selective toxicity: antibiotic must affect target organism. Many have side effects at high concentrations. Some may even cause allergic reaction: drug should affect microbial physiology.
