1
Pathopharmacology Exam 3 Questions with
Answers (100% Correct Answers)
Chapter 83: Selective toxicity Answer: -toxicity to microbes but harmless to
host
Chapter 83: Drug resistance Answer: 4 basic ways that microbes build
resistance:
1) decrease the concentration of a drug at its site of action
2) inactivate a drug
3) alter the chemical structure of drug target molecules
4) produce a drug antagonist
Chapter 83: Acquired resistance Answer: 2 ways to acquire resistance
1) spontaneous mutation (1 drug resistance)
2) conjugation (multiple drug resistance)
Chapter 83: Antibiotic selection process Answer: -identify the organism
-test the drug sensitivity of the organism
-consider the host (patient) factors
-drug may be ruled out due to: allergy, inability to penetrate site of infection,
various patient variables
Chapter 83: Culture & Sensitivity Testing Answer: -CULTURE is what the lab
grows to positively identify the microbe
-SENSITIVITY is the testing done in the petri dish with the disks to see if the
antibiotic is helpful and stops the microbe
,2
-Empiric Therapy: what the lab does when the patient has an acute infection
and cannot wait 48-72 hours for culture-sensitivity test -> a broad spectrum
drug is picked (empiric testing is done quickly and produces the preliminary
results while waiting for the culture and sensitivity test results)
Chapter 84: Why do we get the sample from the patient BEFORE we give any
antibiotics? Answer: If antibiotics are present at the time of sampling, they can
suppress microbial growth in cultures and can thereby confound identification
Chapter 84: Staphylococcus aureus (normal flora and MRSA) Answer: -
Penicillin was introduced in the 1940s and S. aureus was sensitive -> by the
1960s, S. aureus was resistant (in 80% of cases)
-Methicillin-resistant S. aureus (MRSA) produces penicillin proteins with a low
affinity for penicillins and all other beta-lactam antibiotics -> THIS ABILITY
WAS ACQUIRED FROM THE GENES OF OTHER BACTERIA
Chapter 84: Mechanisms of bacterial resistance Answer: 3 factors:
1) inability of penicillins to reach their target
2) inactivation of penicillins by bacterial enzymes
3) production of penicillin-binding proteins that have a low affinity for
penicillins
Chapter 84: Amoxicillin Answer: -ONE OF THE MOST FREQUENTLY
PRESCRIBED ANTIBIOTICS
-Mechanism of action: weaken the cell wall (bacteria takes in too much water
and ruptures); active only against bacteria undergoing growth and division
-Antimicrobial spectrum: bactericidal to numerous gram (+) and gram (-)
organisms; also increased activity against gram (-) bacilli (which look like rods)
-Therapeutic uses: active against a variety of bacteria (broad spectrum)
, 3
-Adverse effects/cautions: fewer side effects than other penicillins; rash,
diarrhea
Chapter 84: What are the 2 different types of bacterial resistance? Answer: -
intrinsic
-acquired
Chapter 85: Cephalosporins - Basic pharmacology Answer: -beta-lactam
antibiotics -> weaken bacterial cell wall
-eliminated by kidneys -> reduced dosage to patients with renal impairment
(REMEMBER! BUN:Creatinine -> 10:1)
-five generations of cephalosporins: as you go from the 1st to 5th generation,
you see:
1) increasing activity against gram (-) bacteria
2) increasing resistance to destruction by beta lactamases
3) increasing ability to reach CSF
Chapter 85: Vancomycin Answer: -Mechanism of action: inhibits cell wall
synthesis
-Antibacterial spectrum: severe infections (MRSA, S. epidermidis, C. diff)
-Therapeutic uses: ONLY FOR GRAM (+) BACTERIA = MRSA, S.
epidermidis, C. diff
-Adverse effects/Cautions: Renal failure (principal effect), allergic reactions,
ototoxicity (ear damage), "Red man" syndrome (red skin due to fast
administration), thrombophlebitis (inflammation of the veins -> common
effect)
Pathopharmacology Exam 3 Questions with
Answers (100% Correct Answers)
Chapter 83: Selective toxicity Answer: -toxicity to microbes but harmless to
host
Chapter 83: Drug resistance Answer: 4 basic ways that microbes build
resistance:
1) decrease the concentration of a drug at its site of action
2) inactivate a drug
3) alter the chemical structure of drug target molecules
4) produce a drug antagonist
Chapter 83: Acquired resistance Answer: 2 ways to acquire resistance
1) spontaneous mutation (1 drug resistance)
2) conjugation (multiple drug resistance)
Chapter 83: Antibiotic selection process Answer: -identify the organism
-test the drug sensitivity of the organism
-consider the host (patient) factors
-drug may be ruled out due to: allergy, inability to penetrate site of infection,
various patient variables
Chapter 83: Culture & Sensitivity Testing Answer: -CULTURE is what the lab
grows to positively identify the microbe
-SENSITIVITY is the testing done in the petri dish with the disks to see if the
antibiotic is helpful and stops the microbe
,2
-Empiric Therapy: what the lab does when the patient has an acute infection
and cannot wait 48-72 hours for culture-sensitivity test -> a broad spectrum
drug is picked (empiric testing is done quickly and produces the preliminary
results while waiting for the culture and sensitivity test results)
Chapter 84: Why do we get the sample from the patient BEFORE we give any
antibiotics? Answer: If antibiotics are present at the time of sampling, they can
suppress microbial growth in cultures and can thereby confound identification
Chapter 84: Staphylococcus aureus (normal flora and MRSA) Answer: -
Penicillin was introduced in the 1940s and S. aureus was sensitive -> by the
1960s, S. aureus was resistant (in 80% of cases)
-Methicillin-resistant S. aureus (MRSA) produces penicillin proteins with a low
affinity for penicillins and all other beta-lactam antibiotics -> THIS ABILITY
WAS ACQUIRED FROM THE GENES OF OTHER BACTERIA
Chapter 84: Mechanisms of bacterial resistance Answer: 3 factors:
1) inability of penicillins to reach their target
2) inactivation of penicillins by bacterial enzymes
3) production of penicillin-binding proteins that have a low affinity for
penicillins
Chapter 84: Amoxicillin Answer: -ONE OF THE MOST FREQUENTLY
PRESCRIBED ANTIBIOTICS
-Mechanism of action: weaken the cell wall (bacteria takes in too much water
and ruptures); active only against bacteria undergoing growth and division
-Antimicrobial spectrum: bactericidal to numerous gram (+) and gram (-)
organisms; also increased activity against gram (-) bacilli (which look like rods)
-Therapeutic uses: active against a variety of bacteria (broad spectrum)
, 3
-Adverse effects/cautions: fewer side effects than other penicillins; rash,
diarrhea
Chapter 84: What are the 2 different types of bacterial resistance? Answer: -
intrinsic
-acquired
Chapter 85: Cephalosporins - Basic pharmacology Answer: -beta-lactam
antibiotics -> weaken bacterial cell wall
-eliminated by kidneys -> reduced dosage to patients with renal impairment
(REMEMBER! BUN:Creatinine -> 10:1)
-five generations of cephalosporins: as you go from the 1st to 5th generation,
you see:
1) increasing activity against gram (-) bacteria
2) increasing resistance to destruction by beta lactamases
3) increasing ability to reach CSF
Chapter 85: Vancomycin Answer: -Mechanism of action: inhibits cell wall
synthesis
-Antibacterial spectrum: severe infections (MRSA, S. epidermidis, C. diff)
-Therapeutic uses: ONLY FOR GRAM (+) BACTERIA = MRSA, S.
epidermidis, C. diff
-Adverse effects/Cautions: Renal failure (principal effect), allergic reactions,
ototoxicity (ear damage), "Red man" syndrome (red skin due to fast
administration), thrombophlebitis (inflammation of the veins -> common
effect)
