Infectious Disease - Pharmacology - Antibiotics Flashcards
What general type of antibiotic is only effective while the bacterium is replicating?
Inhibitors of cell wall synthesis
Name a few general types of test you might order in a patient with an infection of unknown etiology.
Stains (Gram, acid-fast, fungal);
cultures (blood, sputum, urine; aerobic, anaerobic);
molecular (NAAT, PCR)
When are inhibitors of bacterial cell wall synthesis effective?
When are inhibitors of cell metabolic activity / central dogma effective?
Only while the cell is replicating;
all the time
Name two quantitative methods by which antibiotic sensitivity can be measured in a culture.
Broth dilutions;
E-test
Name a qualitative method by which antibiotic sensitivity can be tested in a culture.
Disc diffusion
(Kirby-Bauer discs)
How does an E-test work in determining antibiotic sensitivity in culture?
Is it quantitative or qualitative?
A rod with antibiotic gradations is placed in culture;
quantitative
How can a minimum inhibitory concentration be determined for an antibiotic and a particular bacterial strain?
Dilutions
________-dependent killing agents kill gram-________ bacteria during the time at which the serum drug concentration is ________ than the MIC for the bacteria.
Time-dependent killing agents kill gram-negative bacteria during the time at which the serum drug concentration is higher than the MIC for the bacteria.
(The antibiotic must be present above MIC for a certain period of time. T > MIC)
________-dependent killing agents kill bacteria when the serum drug concentration is ________ than the MIC for the bacteria.
Concentration-dependent killing agents kill bacteria when the serum drug concentration is much higher than the MIC for the bacteria.
(The antibiotic must be well above MIC to have an effect.)
The post-antibiotic effect.
Some antibiotics continue ______ ______ for some time (≥ 1.5 hours) after serum levels drop below the _____.
The post-antibiotic effect.
Some antibiotics continue inhbiting growth for some time (≥ 1.5 hours) after serum levels drop below the MIC.
The ___________ effect.
Some antibiotics continue inhbiting growth for some time (≥ 1.5 hours) after serum levels drop below the MIC.
The post-antibiotic effect.
Some antibiotics continue inhbiting growth for some time (≥ 1.5 hours) after serum levels drop below the MIC.
Most antibiotics have significant post-antibiotic effects on Gram-___________ bacteria.
Only carbapenems and DNA/protein synthesis blockers have significant post-antibiotic effects on Gram-___________ bacteria.
Most antibiotics have significant post-antibiotic effects on Gram-positive bacteria.
Only carbapenems and DNA/protein synthesis blockers have significant post-antibiotic effects on Gram-negative bacteria.
Name a few things to keep in mind when prescribing medications:
History of ________ reactions, ______, renal function (________ clearance), ______ function, _______, critical illness, genomics (slow v. rapid acetylators, etc.), pregnancy, breast-feeding, G6PD deficiency, etc.
Name a few things to keep in mind when prescribing medications:
History of adverse reactions, age, renal function (creatinine clearance), hepatic function, weight, critical illness, genomics (slow v. rapid acetylators, etc.), pregnancy, breast-feeding, G6PD deficiency, etc.
Name a few things to keep in mind when prescribing medications:
History of adverse reactions, age, _______ function (creatinine clearance), hepatic function, weight, critical illness, _______ (slow v. rapid acetylators, etc.), ________, breast-feeding, G6PD deficiency, etc.
Name a few things to keep in mind when prescribing medications:
History of adverse reactions, age, renal function (creatinine clearance), hepatic function, weight, critical illness, genomics (slow v. rapid acetylators, etc.), pregnancy, breast-feeding, G6PD deficiency, etc.
Name a few organs or situations in which organs are difficult to reach with antibiotics BESIDES the blood-brain, blood-testis, or placental barriers.
Prostate (difficult to reach);
dead bone (no blood flow)
Determine if the following medications/classes are safe during pregnancy or not:
Penicillins
Cephalosporins
Tetracyclines
Clindamycin
Metronidazole
Azithromycin
All safe except tetracyclines
In order to treat intracellular bacteria (e.g. Salmonella spp., Chlamydia spp., Rickettsia spp., etc.), an antibiotic that is _______-soluble should be selected.
In order to treat intracellular bacteria (e.g. Salmonella spp., Chlamydia spp., Rickettsia spp., etc.), an antibiotic that is lipid-soluble should be selected.
Name three classes of β-lactam antibiotics.
Penicillins;
cephalosporins;
carbapenems
Penicillin ___ is for IV use.
Penicillin ___ is for oral use.
Penicillin G is for IV use.
Penicillin V is for oral use.
What are the two natural penicillins?
Penicillin G;
penicillin V
Name a few penicillins that are β-lactamase resistant.
Methicillin;
oxacillin;
nafcillin
Name two aminopenicillins.
Ampicillin;
amoxicillin
Name two anti-pseudomonal penicillins.
Piperacillin;
ticarcillin
Name three β-lactamase inhibitors.
Clavulinic acid;
tazobactam;
sulbactam
Name a carbapenem.
Meropenem
Name a monobactam.
Aztreonam
How are cephalosporins identified via nomenclature?
What is an example?
Prefix: Cef- or ceph-
e.g. ceftriaxone
What type of medication is vancomycin?
Name another medication in this category.
Glycopeptide;
bacitracin
What suffix is given to macrolides?
Give an example.
-thromycin
azithromycin
What are the two main aminoglycosides?
Gentamicin;
tobramycin
What suffix is typically given to tetracyclines?
What is a common example?
-cycline
doxycycline
What prefix or suffix is given to fluoroquinolones?
What is an example?
-floxacin
levofloxacin
Name the antibiotic class (and two example medications) that inhibit general peptidoglycan synthesis.
Glycopeptides;
vancomycin, bacitracin
Name an antibiotic that inhibits mRNA synthesis by blocking bacterial RNA polymerase.
Rifampin
Name a specific medication and an alternate drug class that both inhibit bacterial folic acid synthesis.
Trimethoprim;
sulfonamides
(sulfamethoxazole, sulfadizine, sulfasoxazole)
Name an antibiotic that decreases DNA integrity by increasing free radical formation.
Metronidazole
Name two medication classes that both inhibit bacterial DNA gyrase (topoisomerase II).
Fluoroquinolones;
quinolones
Name two antibiotic classes that both inhibit the bacterial 30S subunit.
Aminoglycosides;
tetracyclines
Name three medications and two antibiotic classes that all inhibit the bacterial 50S subunit.
Medications: chloramphenicol, clindamycin, linezolid;
classes: macrolides, streptogramins
Name five antibiotic classes that all inhibit peptidoglycan cross-linking.
Penicillins;
antipseudomonals;
cephalosporins;
carbapenems;
monobactams
Describe the method of action of the following medication(s):
Glycopeptides
(vancomycin, bacitracin)
Inhibition of general peptidoglycan synthesis
Describe the method of action of the following medication(s):
Rifampin
Inhibition of bacterial RNA polymerase
Describe the method of action of the following medication(s):
Trimethoprim;
sulfonamides (sulfamethoxazole, sulfadizine, sulfasoxazole)
Inhibit bacterial folic acid synthesis
Describe the method of action of the following medication(s):
Metronidazole
Decreases DNA integrity by increasing free radical formation
Describe the method of action of the following medication(s):
Fluoroquinolones;
quinolones
Inhibit bacterial DNA gyrase (topoisomerase II)
Describe the method of action of the following medication(s):
Aminoglycosides;
tetracyclines
Inhibit the bacterial 30S subunit
Describe the method of action of the following medication(s):
Medications: chloramphenicol, clindamycin, linezolid;
classes: macrolides, streptogramins
Inhibit the bacterial 50S subunit
Describe the method of action of the following medication(s):
Penicillins;
cephalosporins;
carbapenems;
monobactams
Inhibit peptidoglycan cross-linking
Are tetracyclines bactericidal or bacteriostatic?
Bacteriostatic
Is metronidazole bactericidal or bacteriostatic?
Bactericidal
Are macrolides bactericidal or bacteriostatic?
Bacteriostatic
Are β-lactams (penicillins, cephalosporins, carbapenems) bactericidal or bacteriostatic?
Bactericidal
Is vancomycin bactericidal or bacteriostatic?
Bactericidal
Is trimethoprim bactericidal or bacteriostatic?
Bacteriostatic
Are fluoroquinolones bactericidal or bacteriostatic?
Bactericidal
Are sulfonamides bactericidal or bacteriostatic?
Bacteriostatic
How do beta-lactams damage the bacterial cell walls?
Inhibition of peptidoglycan cross-linking
(via binding of penicillin-binding proteins)
What enzyme type performs the final steps of peptidoglycan cell wall formation for bacteria?
Penicillin-binding proteins
Fill in the blanks for the three main mechanisms by which bacteria can resist beta-lactam activity.
- Altered ______ability.
- Production of _____________.
- Alterations to _____________ proteins.
Fill in the blanks for the three main mechanisms by which bacteria can resist beta-lactam activity.
- Altered permeability.
- Production of beta-lactamases.
- Alterations to penicillin-binding proteins.
Bacteria are characterized by a high _________ (internal/external) osmotic pressure.
So defects in the integrity of their peptidoglycan can have major deleterious effects.
Bacteria are characterized by a high internal osmotic pressure.
So defects in the integrity of their peptidoglycan can have major deleterious effects.