Microbiology exam 3; Antimicrobial
drugs with complete solution
Types of antimicrobial drugs - correct answer ✔✔ 1. synthetic drugs
2. antibiotics
synthetic drugs - correct answer ✔✔ human made
antibiotics - correct answer ✔✔ produced by microorganisms to offer selective survival
advantage to host organisms
goal: kill competitors
criteria for determining whether an antimicrobial drug is effective for use in humans - correct
answer ✔✔ 1. selective toxicity: agains microbes under treatment and not human host cells
2. not cause hypersensitive reactions in most hosts
3. ease of delivery to target sites: soluble in body fluids & not rapidly broken down or excreted
4. microbes being treated should not readily develop resistance
why don't we use broad spectrum drugs to treat all diseases - correct answer ✔✔ they destroy
normal flora that keeps pathogens or potential resistant flora in check
broad spectrum drugs - correct answer ✔✔ kill wide range of microorganisms
advantage: save time by killing everything
narrow spectrum drugs - correct answer ✔✔ kill specific group of microorganisms
, why choose a particular drug for treatment - correct answer ✔✔ 1. type of microbe: drugs show
different ability to penetrate bacteria, different target enzymes, different cell structures
2. site of infection: drug accessibility
3. resistance
how do you determine what drug a particular microbe is susceptible to - correct answer ✔✔
tests for microbial susceptibility
1. identify microbe
2. isolate organism
3. sensitivity testing: disk diffusion method & broth diffusion method
what are the major targets of antimicrobial drugs - correct answer ✔✔ 1. inhibition of cell wall
synthesis
2. inhibition of protein synthesis
3. injury to the plasma membrane
4. inhibition of enzymatic activity: competitive inhibitor enzyme resembles normal substrate &
inhibition of nucleic acid synthesis
how does microbe become resistant to a particular drug - correct answer ✔✔ 1. destruction
2. uptake reduction
3. target change
destruction - correct answer ✔✔ acquire enzymes that degrade drug resistance factors on
plasmids
why is penicillin not effective against gram negative bacteria - correct answer ✔✔ gram negative
cell wall has a thin layer of peptidoglycan & this outer lipid membrane inhibits penetration of
the drug
drugs with complete solution
Types of antimicrobial drugs - correct answer ✔✔ 1. synthetic drugs
2. antibiotics
synthetic drugs - correct answer ✔✔ human made
antibiotics - correct answer ✔✔ produced by microorganisms to offer selective survival
advantage to host organisms
goal: kill competitors
criteria for determining whether an antimicrobial drug is effective for use in humans - correct
answer ✔✔ 1. selective toxicity: agains microbes under treatment and not human host cells
2. not cause hypersensitive reactions in most hosts
3. ease of delivery to target sites: soluble in body fluids & not rapidly broken down or excreted
4. microbes being treated should not readily develop resistance
why don't we use broad spectrum drugs to treat all diseases - correct answer ✔✔ they destroy
normal flora that keeps pathogens or potential resistant flora in check
broad spectrum drugs - correct answer ✔✔ kill wide range of microorganisms
advantage: save time by killing everything
narrow spectrum drugs - correct answer ✔✔ kill specific group of microorganisms
, why choose a particular drug for treatment - correct answer ✔✔ 1. type of microbe: drugs show
different ability to penetrate bacteria, different target enzymes, different cell structures
2. site of infection: drug accessibility
3. resistance
how do you determine what drug a particular microbe is susceptible to - correct answer ✔✔
tests for microbial susceptibility
1. identify microbe
2. isolate organism
3. sensitivity testing: disk diffusion method & broth diffusion method
what are the major targets of antimicrobial drugs - correct answer ✔✔ 1. inhibition of cell wall
synthesis
2. inhibition of protein synthesis
3. injury to the plasma membrane
4. inhibition of enzymatic activity: competitive inhibitor enzyme resembles normal substrate &
inhibition of nucleic acid synthesis
how does microbe become resistant to a particular drug - correct answer ✔✔ 1. destruction
2. uptake reduction
3. target change
destruction - correct answer ✔✔ acquire enzymes that degrade drug resistance factors on
plasmids
why is penicillin not effective against gram negative bacteria - correct answer ✔✔ gram negative
cell wall has a thin layer of peptidoglycan & this outer lipid membrane inhibits penetration of
the drug
