Day 10 Flashcards
What were the first synthetic drugs called?
Chemotherapeutic agents
When were sulfa drugs developed?
In WWII
Who discovered Penicillin and when?
Alexander Fleming in 1928
Chemical substances produced by bacteria and fungi to destroy or inhibit the growth of microorganisms
Natural antibiotics
Antibiotics synthetically prepared from chemical substances
Synthetic antibiotics
What is Broad Spectrum?
Effective against a broad range of microorganisms
What is a disadvantage of using a broad spectrum?
it might kill or reduce the numbers of beneficial normal flora
What is a Limited Spectrum?
Effective against a narrow range of microorganisms
Define BACTERIOCIDAL.
Kills the target microorganism
Define BACTERIOSTATIC.
Prevents replication or growth of target microorganisms
What are the 5 modes of antibiotic action?
- inhibition of cell wall synthesis
- inhibition of protein wall synthesis(amino glycosides and macrolides)
- Cytoplasmic membrane injury(bacitracin)
- inhibition of protein synthesis (DNA/RNA)
- inhibition of synthesis of essential metabolites (sulfonamides)
Microorganisms may pick up _________ from other bacteria which inhibit the drugs ability to affect the bacteria
Genes(plasmids)
Combined action of the two drugs is indifferent or no greater than the more effective agent used alone
Indifference
Combined action of the two drugs is additive or equal to the sum of activity of each drug is used individually
Addition
Combined effect of two drugs is greater than the combined effect of each individual drug acting alone( the effect is amplified)
Synergy
The action of one antibiotic interferes with the action of another administered antibiotic
Antagonism
What are the two methods of susceptibility testing?
Dilution
Disk diffusion
What’s another name for Disk diffusion?
Kirby- Bauer method
Lowest concentration of antibiotic that inhibits growth of organism
MIC -Minimum Inhibition Concentration
What are 2 advantages of Dilution Method?
- Quantitative;most accurate
- Can be easily adapted to automated systems
What is a disadvantage of Dilution Method?
Time consuming
What is the principle of KB method?
An antibiotic disc is placed on heavy bacterial growth on a Mueller-Hinton agar plate
What variables affect the size of zone of inhibition in the diffusion method?
- the ability and rate of diffusion of the antibiotic into the medium
- the turbidity of the bacterial suspension inoculated
- the growth rate of the organism
- the degree of sensitivity of the organisms to the antibiotic
What are advantages of KB method?
- economical
- simple
- reproducible
Large zone of no growth
Sensitive or susceptible
Small zone of no growth
Intermediate
Zone of growth up to the disc
Resistant
How is bacteria reported to practitioner?
Susceptible,intermediate or resistant
