BI 234 ELEMENTARY MICROBIOLOGY CHAPTERS 20-26 EXAM
QUESTIONS AND ANSWERS
Chapter 20
Antimicrobial Drugs
Chemotherapy
treatment with chemical substances
Antibiotic
substances produced by microorganism that inhibits another microorganism
Spectrum of activity
range of different microbes affected by an antibiotic
Bactericidal
killing bacteria directly
Bacteriostatic
preventing bacterial growth
Selective toxicity
a drug that kills harmful microbes without damaging the host
When initially treating a primary infection what spectrum of antibiotics will be
most effective?
broad spectrum
5 modes of antibiotic action
,Inhibition of cell wall synthesis, Inhibition of protein synthesis, injury to the plasma
membrane, inhibition of nucleic acid synthesis, inhibition of synthesis of essential
metabolism
penicillins, cephalosporins, bacitracin, vancomycin, isoniazid, and ethambutol
antibiotics that inhibit cell wall synthesis
aminoglycosides, tetracyclines, chloramphenicol, and macrolides
take advantage of 70S bacterial ribosomes to inhibit microbial protein synthesis.
polymixin B
causes disruption and change in permeability of the cell membrane to perform this
antimicrobial function.
Which antibiotic inhibits nucleaic acid synthesis?
Riamycins (rifampin), quinolones, fluoroquinolones (including ciproflaxin) interfer with
transcription and replication to operate within this antimicrobial modality.
Which antibiotic inhibits the synthesis of essential cell metabolites?
Sulfonimides - sulfa drugs, including trimethoprim and sulfamethoxazole - inhibit
enzyme activity as agents of this antimicrobial modality.
Penicillin G
Natural penicillin that requires injection
Penicillin V
natural penicilin that can be taken orally
Oxacillin
a semisynthetic penicillin that only acts on gram-positives and is resistant to
penecillinase
,Ampicillin
an extended spectrum semi-synthetic penicillin
Penicillin
An antibiotic that comes in natural and semi-synthetic varieties.
Bactrican
is a topical antibiotic effective againnst gram positives.
Vancomycin
is an important "last line" against antibiotic resistant S. aureus. 2Nd, 3rd, and 4th
generation
cephalosporins
are more effective against gram negatives.
Isoniazid
inhibits mycolic acid synthesis.
Ethambutol
inhibits incorporation of mycolic acid.
A bacteriostatic antibiotic we studied
Penicillin is an example of an antibiotic with this specific action that it prevents synthesis
of bacterial cell walls during reproduction.
Discuss the effect of penecillin retention and action relatives to administration,
dose, and type.
Depedning on dose, formulation, and administration pencillin will reach various
concentrations in the blood for varied amounts of time. This will have an effect on it
antimicrobial function.
, Penecillinase
This enzymne, produced by bacteria, cleaves the beta-lactam ring of penicillin rendering
it inactive. This is a method antibiotic resistance
Cepalosporin
This antibiotic is resistant to pencillinase because it has a different molecular nucleus
than penicillin. This can be used to treat infections of Penicillin resistant microbes.
Chlorampehenicol
is a broad spectrum antibiotic that inhibits bacterial protein synthesis by binding to the
50S ribosomal subunit to inhibit peptide bond formation
Aminoglycosides (streptomycin, neomycin, gentamycin)
broad spectrum antibiotics that inhibit bacterial protein synthesis by changing the shape
of the 30S subunit to prevent correct translation of mRNA
Tetracyclines
broad spectrum antibiotics that inhibit bacterial protein synthesis by interference with
tRNA attachment to mRNA
Macrolides (IE: erythromycin)
Inhibit protein synthesis in gram positive bacteria by binding to 50S ribosomal subunits
to prevent translocation.
The antibiotics that inhibit bacterial protein synthesis.
Chloramphenicol, aminoglycosides, tetracyclines, macrolides
Polymyxin B
a topical antibiotic that causes injury to the plasma membrane. It is often combined with
bacitracin and neomycin in over the counter preparations.
QUESTIONS AND ANSWERS
Chapter 20
Antimicrobial Drugs
Chemotherapy
treatment with chemical substances
Antibiotic
substances produced by microorganism that inhibits another microorganism
Spectrum of activity
range of different microbes affected by an antibiotic
Bactericidal
killing bacteria directly
Bacteriostatic
preventing bacterial growth
Selective toxicity
a drug that kills harmful microbes without damaging the host
When initially treating a primary infection what spectrum of antibiotics will be
most effective?
broad spectrum
5 modes of antibiotic action
,Inhibition of cell wall synthesis, Inhibition of protein synthesis, injury to the plasma
membrane, inhibition of nucleic acid synthesis, inhibition of synthesis of essential
metabolism
penicillins, cephalosporins, bacitracin, vancomycin, isoniazid, and ethambutol
antibiotics that inhibit cell wall synthesis
aminoglycosides, tetracyclines, chloramphenicol, and macrolides
take advantage of 70S bacterial ribosomes to inhibit microbial protein synthesis.
polymixin B
causes disruption and change in permeability of the cell membrane to perform this
antimicrobial function.
Which antibiotic inhibits nucleaic acid synthesis?
Riamycins (rifampin), quinolones, fluoroquinolones (including ciproflaxin) interfer with
transcription and replication to operate within this antimicrobial modality.
Which antibiotic inhibits the synthesis of essential cell metabolites?
Sulfonimides - sulfa drugs, including trimethoprim and sulfamethoxazole - inhibit
enzyme activity as agents of this antimicrobial modality.
Penicillin G
Natural penicillin that requires injection
Penicillin V
natural penicilin that can be taken orally
Oxacillin
a semisynthetic penicillin that only acts on gram-positives and is resistant to
penecillinase
,Ampicillin
an extended spectrum semi-synthetic penicillin
Penicillin
An antibiotic that comes in natural and semi-synthetic varieties.
Bactrican
is a topical antibiotic effective againnst gram positives.
Vancomycin
is an important "last line" against antibiotic resistant S. aureus. 2Nd, 3rd, and 4th
generation
cephalosporins
are more effective against gram negatives.
Isoniazid
inhibits mycolic acid synthesis.
Ethambutol
inhibits incorporation of mycolic acid.
A bacteriostatic antibiotic we studied
Penicillin is an example of an antibiotic with this specific action that it prevents synthesis
of bacterial cell walls during reproduction.
Discuss the effect of penecillin retention and action relatives to administration,
dose, and type.
Depedning on dose, formulation, and administration pencillin will reach various
concentrations in the blood for varied amounts of time. This will have an effect on it
antimicrobial function.
, Penecillinase
This enzymne, produced by bacteria, cleaves the beta-lactam ring of penicillin rendering
it inactive. This is a method antibiotic resistance
Cepalosporin
This antibiotic is resistant to pencillinase because it has a different molecular nucleus
than penicillin. This can be used to treat infections of Penicillin resistant microbes.
Chlorampehenicol
is a broad spectrum antibiotic that inhibits bacterial protein synthesis by binding to the
50S ribosomal subunit to inhibit peptide bond formation
Aminoglycosides (streptomycin, neomycin, gentamycin)
broad spectrum antibiotics that inhibit bacterial protein synthesis by changing the shape
of the 30S subunit to prevent correct translation of mRNA
Tetracyclines
broad spectrum antibiotics that inhibit bacterial protein synthesis by interference with
tRNA attachment to mRNA
Macrolides (IE: erythromycin)
Inhibit protein synthesis in gram positive bacteria by binding to 50S ribosomal subunits
to prevent translocation.
The antibiotics that inhibit bacterial protein synthesis.
Chloramphenicol, aminoglycosides, tetracyclines, macrolides
Polymyxin B
a topical antibiotic that causes injury to the plasma membrane. It is often combined with
bacitracin and neomycin in over the counter preparations.
