Question 1

Please select the False statement regarding tissue distribution, metabolism, and excretion of medications.

Accepted Answer

A)  Patients who have liver dysfunction often metabolize medications more slowly, so their doses must be adjusted to avoid toxic levels. 
B)  The half-life of a medication is the time it takes for the serum concentration of that chemical to decrease by 100%. 
C)  Medications that are unstable at low pH are typically given by intravenous or intramuscular injection. 
D)  A medication with a half-life of over 24 hours is taken only once a day or less. 
E)  A medication that has a very short half-life usually needs to be taken several times a day. 
A)  Patients who have liver dysfunction often metabolize medications more slowly, so their doses must be adjusted to avoid toxic levels. 
B)  The half-life of a medication is the time it takes for the serum concentration of that chemical to decrease by 100%. 
C)  Medications that are unstable at low pH are typically given by intravenous or intramuscular injection. 
D)  A medication with a half-life of over 24 hours is taken only once a day or less. 
E)  A medication that has a very short half-life usually needs to be taken several times a day. B

Question 2

Why are nucleoside analogs active only against replicating viruses?

Accepted Answer

A)  These drugs can only be taken up by cells that are infected by viruses. They are shut out from non-infected cells. This makes them effective only against cells where viruses are replicating. 
B)  Each of these drugs is specifically activated by enzymes produced by the viruses. The viruses will only produce these enzymes when they are replicating, so the drugs can only become activated when these processes are occurring. 
C)  Nucleoside analogs work by directly inhibiting the activity of nucleic acid polymerases. If the virus isn't actively replicating, there's no DNA/RNA polymerase active for the drug to inhibit, so the drug cannot work. 
D)  Nucleoside analogs work by being incorporated into growing strands of DNA/RNA. This indirectly shuts down further extension of these chains. However, new strands of viral DNA/RNA are only being created when the virus is replicating. Thus, these drugs can only work when the virus is actively replicating as well. 
E)  Nucleoside analogs work by being incorporated into growing strands of amino acids during enzyme synthesis. This indirectly shuts down further extension of these chains. However, new viral proteins are only being created when the virus is replicating, so these medications only work if that is the case. 
A)  These drugs can only be taken up by cells that are infected by viruses. They are shut out from non-infected cells. This makes them effective only against cells where viruses are replicating. 
B)  Each of these drugs is specifically activated by enzymes produced by the viruses. The viruses will only produce these enzymes when they are replicating, so the drugs can only become activated when these processes are occurring. 
C)  Nucleoside analogs work by directly inhibiting the activity of nucleic acid polymerases. If the virus isn't actively replicating, there's no DNA/RNA polymerase active for the drug to inhibit, so the drug cannot work. 
D)  Nucleoside analogs work by being incorporated into growing strands of DNA/RNA. This indirectly shuts down further extension of these chains. However, new strands of viral DNA/RNA are only being created when the virus is replicating. Thus, these drugs can only work when the virus is actively replicating as well. 
E)  Nucleoside analogs work by being incorporated into growing strands of amino acids during enzyme synthesis. This indirectly shuts down further extension of these chains. However, new viral proteins are only being created when the virus is replicating, so these medications only work if that is the case. D

Question 3

Which of the following targets would you expect to be the most selective with respect to toxicity?

Accepted Answer

A)  Peptidoglycan synthesis 
B)  70S ribosome 
C)  DNA synthesis 
D)  Glycolysis 
E)  Cytoplasmic membrane function 
A)  Peptidoglycan synthesis 
B)  70S ribosome 
C)  DNA synthesis 
D)  Glycolysis 
E)  Cytoplasmic membrane function A

Question 4

One of the earliest researchers to explore the use of chemicals to kill microbial pathogens was

Accepted Answer

A)  Koch. 
B)  Ehrlich. 
C)  Hooke. 
D)  Fleming. 
E)  Salvarsan. 
A)  Koch. 
B)  Ehrlich. 
C)  Hooke. 
D)  Fleming. 
E)  Salvarsan.

Question 5

Which of the following would you prescribe to treat a person with M. pneumoniae?

Accepted Answer

A)  A β-lactam antibiotic such as penicillin 
B)  A glycopeptide antibiotic such as vancomycin 
C)  Bacitracin 
D)  A macrolide such as erythromycin 
E)  Bacitracin OR penicillin 
A)  A β-lactam antibiotic such as penicillin 
B)  A glycopeptide antibiotic such as vancomycin 
C)  Bacitracin 
D)  A macrolide such as erythromycin 
E)  Bacitracin OR penicillin

Question 6

Prontosil effectively acted on streptococci when the drug was split by enzymes to produce

Accepted Answer

A)  penicillin. 
B)  sulfanilamide. 
C)  erythromycin. 
D)  Salvarsan. 
E)  Salvarsan AND penicillin. 
A)  penicillin. 
B)  sulfanilamide. 
C)  erythromycin. 
D)  Salvarsan. 
E)  Salvarsan AND penicillin.

Question 7

The toxicity of a given drug is expressed as the

Accepted Answer

A)  selective toxicity. 
B)  therapeutic index. 
C)  biocide index. 
D)  biostatic index. 
E)  bacteriostatic window. 
A)  selective toxicity. 
B)  therapeutic index. 
C)  biocide index. 
D)  biostatic index. 
E)  bacteriostatic window.

Question 8

Gonorrhea is a sexually transmitted infection (STI) caused by the diplococcus Neisseria gonorrhoeae, commonly called gonococcus (GC). This organism developed resistance to penicillin and tetracycline in the 1980s, after which fluoroquinolones were the recommended drugs for treating GC. Subsequent resistance to the fluoroquinolones has led to the current recommended treatment of injected ceftriaxone in combination with oral azithromycin. Although this approach continues to be effective, recent data from the CDC indicates that resistance to azithromycin is emerging.
-Initially, GC was treated with penicillin, which targets ________, and tetracycline which targets ________.

Accepted Answer

A)  protein synthesis; peptidoglycan synthesis 
B)  peptidoglycan synthesis; protein synthesis 
C)  protein synthesis; capsule formation 
D)  capsule formation; ergesterol formation 
E)  cell membrane integrity; folic acid synthesis 
A)  protein synthesis; peptidoglycan synthesis 
B)  peptidoglycan synthesis; protein synthesis 
C)  protein synthesis; capsule formation 
D)  capsule formation; ergesterol formation 
E)  cell membrane integrity; folic acid synthesis

Question 9

Antimicrobial resistance can be due to spontaneous mutation or gene acquisition.

Accepted Answer

A) True 
 B)False

Question 10

Fluoroquinolones act by inhibiting DNA gyrase, an enzyme involved in DNA replication. Resistance to this antibiotic is most commonly by

Accepted Answer

A)  a change in the DNA gyrase target, an example of acquired resistance. 
B)  enzymatic modification of the ribosomal target, an example of innate resistance. 
C)  a change in the DNA gyrase target, an example of innate resistance. 
D)  due to a mutation in the gene that encodes RNA polymerase, an example of adaptive resistance. 
E)  increased efflux of the drug from the target cell, an example of innate resistance. 
A)  a change in the DNA gyrase target, an example of acquired resistance. 
B)  enzymatic modification of the ribosomal target, an example of innate resistance. 
C)  a change in the DNA gyrase target, an example of innate resistance. 
D)  due to a mutation in the gene that encodes RNA polymerase, an example of adaptive resistance. 
E)  increased efflux of the drug from the target cell, an example of innate resistance.

Question 11

Antifungal drugs usually target the cell membrane.

Accepted Answer

A) True 
 B)False

Question 12

The rate of elimination of an antimicrobial is expressed as its

Accepted Answer

A)  metabolic destructive rate. 
B)  half-life. 
C)  effective time. 
D)  dosage rate. 
E)  therapeutic index. 
A)  metabolic destructive rate. 
B)  half-life. 
C)  effective time. 
D)  dosage rate. 
E)  therapeutic index.

Question 13

Antibiotics that affect various strains of Gram-positive bacteria and various strains of Gram-negative bacteria are called

Accepted Answer

A)  isolate usable. 
B)  stress-induced. 
C)  broad-spectrum. 
D)  narrow-spectrum. 
E)  intermediate. 
A)  isolate usable. 
B)  stress-induced. 
C)  broad-spectrum. 
D)  narrow-spectrum. 
E)  intermediate.

Question 14

What are two advantages of automated tests used to determine antimicrobial susceptibility?

Accepted Answer

A)  They are easier to perform. 
B)  They produce results more quickly than conventional tests. 
C)  They produce results more quickly than conventional tests AND they are easier to perform. 
D)  They take longer to perform BUT they give fewer False results. 
E)  They are cheaper than conventional tests AND they give more accurate results. 
A)  They are easier to perform. 
B)  They produce results more quickly than conventional tests. 
C)  They produce results more quickly than conventional tests AND they are easier to perform. 
D)  They take longer to perform BUT they give fewer False results. 
E)  They are cheaper than conventional tests AND they give more accurate results.

Question 15

In what clinical situation is it most appropriate to use a broad-spectrum antimicrobial?

Accepted Answer

A)  In an example of a viral pediatric otitis media (middle ear) infection. We can't properly test for the specific drug that would best eliminate the infection due to its location, so we use a broad-spectrum drug instead. 
B)  In a case of viral meningitis. The infection spreads so quickly that we must treat it with an antibacterial drug as quickly as possible. We don't have time to determine which drug will work best, because the patient will die in the meantime. 
C)  In a case of bacterial meningitis. The infection spreads so quickly that we must treat it with an antibacterial drug as quickly as possible. We don't have time to determine which drug will work best, because the patient will die in the meantime. 
D)  In a case of Staphylococcus aureus skin infection. Since this microbe can be resistant to several types of drugs, we want to use one that has the broadest spectrum possible to treat this microbe-specific infection. 
E)  There are no appropriate situations for using broad-spectrum antibiotics, because they almost always lead to resistance. It is much better to use a narrow-spectrum medication. 
A)  In an example of a viral pediatric otitis media (middle ear) infection. We can't properly test for the specific drug that would best eliminate the infection due to its location, so we use a broad-spectrum drug instead. 
B)  In a case of viral meningitis. The infection spreads so quickly that we must treat it with an antibacterial drug as quickly as possible. We don't have time to determine which drug will work best, because the patient will die in the meantime. 
C)  In a case of bacterial meningitis. The infection spreads so quickly that we must treat it with an antibacterial drug as quickly as possible. We don't have time to determine which drug will work best, because the patient will die in the meantime. 
D)  In a case of Staphylococcus aureus skin infection. Since this microbe can be resistant to several types of drugs, we want to use one that has the broadest spectrum possible to treat this microbe-specific infection. 
E)  There are no appropriate situations for using broad-spectrum antibiotics, because they almost always lead to resistance. It is much better to use a narrow-spectrum medication.

Question 16

Acyclovir is selective and low in toxicity, causing little harm to uninfected cells, because

Accepted Answer

A)  only a virally encoded enzyme can convert the medication into its active form (from nucleoside analog to nucleotide analog). 
B)  only a virally encoded enzyme can convert the medication into its active form (from nucleotide analog to nucleoside analog). 
C)  viral DNA is structurally very different from cellular DNA. 
D)  host cells have the ability to repair the damage caused by nucleotide analogs. 
E)  host cells have an enzyme that prevents the conversion of the medication into its active form. 
A)  only a virally encoded enzyme can convert the medication into its active form (from nucleoside analog to nucleotide analog). 
B)  only a virally encoded enzyme can convert the medication into its active form (from nucleotide analog to nucleoside analog). 
C)  viral DNA is structurally very different from cellular DNA. 
D)  host cells have the ability to repair the damage caused by nucleotide analogs. 
E)  host cells have an enzyme that prevents the conversion of the medication into its active form.

Question 17

Broad-spectrum antibiotics have minimal effect on the normal microbiota.

Accepted Answer

A) True 
 B)False

Question 18

Which of the following groups of microorganisms produces antibiotics?

Accepted Answer

A)  Penicillium AND Bacillus 
B)  Streptomyces AND Bacillus 
C)  Bacillus, Penicillium, AND Streptomyces 
D)  Penicillium AND Streptomyces 
E)  Clostridium AND Streptomyces 
A)  Penicillium AND Bacillus 
B)  Streptomyces AND Bacillus 
C)  Bacillus, Penicillium, AND Streptomyces 
D)  Penicillium AND Streptomyces 
E)  Clostridium AND Streptomyces

Question 19

A commercial modification of the disk diffusion test is called the

Accepted Answer

A)  E test. 
B)  D test. 
C)  C test. 
D)  B test. 
E)  A test. 
A)  E test. 
B)  D test. 
C)  C test. 
D)  B test. 
E)  A test.

Question 20

Why would it be important for the Kirby-Bauer disc diffusion test to use a standard concentration (number of cells in the sample) of each of the bacterial strains being tested?

Accepted Answer

A)  If you were to use one strain that was stationary phase (high concentration, replicating very slowly or not at all), and another strain that was just beginning log phase (low concentration but replicating quickly), you could see different results in the test, affecting your interpretation. 
B)  Growth on the Mueller-Hinton agar plates utilized is very sensitive to the phase of the growth curve the bacteria are in when they are placed on the plate.  If they are not in the log phase when they are placed on the plate, they will not grow and the test will be worthless. 
C)  Antibiotic resistance is usually only manifested by bacteria that have achieved a very high concentration. It's important to use bacteria specifically at this particular point for disc diffusion testing. 
D)  Antibiotics only work within a narrow range of cell concentrations. If you use a concentration that is too low or too high, you will get inaccurate measurements of the zone of inhibition. 
E)  Bacteria only develop resistance when there are more than 10¹² cells/ mL. If resistance is to be detected, the test must use at least this concentration of cells. If fewer cells are used, no zone of inhibition will develop. 
A)  If you were to use one strain that was stationary phase (high concentration, replicating very slowly or not at all), and another strain that was just beginning log phase (low concentration but replicating quickly), you could see different results in the test, affecting your interpretation. 
B)  Growth on the Mueller-Hinton agar plates utilized is very sensitive to the phase of the growth curve the bacteria are in when they are placed on the plate.  If they are not in the log phase when they are placed on the plate, they will not grow and the test will be worthless. 
C)  Antibiotic resistance is usually only manifested by bacteria that have achieved a very high concentration. It's important to use bacteria specifically at this particular point for disc diffusion testing. 
D)  Antibiotics only work within a narrow range of cell concentrations. If you use a concentration that is too low or too high, you will get inaccurate measurements of the zone of inhibition. 
E)  Bacteria only develop resistance when there are more than 10¹² cells/ mL. If resistance is to be detected, the test must use at least this concentration of cells. If fewer cells are used, no zone of inhibition will develop.

Exam 20: Antimicrobial Medications

Please select the False statement regarding tissue distribution, metabolism, and excretion of medications.

Why are nucleoside analogs active only against replicating viruses?

Which of the following targets would you expect to be the most selective with respect to toxicity?

One of the earliest researchers to explore the use of chemicals to kill microbial pathogens was

Which of the following would you prescribe to treat a person with M. pneumoniae?

Prontosil effectively acted on streptococci when the drug was split by enzymes to produce

The toxicity of a given drug is expressed as the

Antimicrobial resistance can be due to spontaneous mutation or gene acquisition.

Fluoroquinolones act by inhibiting DNA gyrase, an enzyme involved in DNA replication. Resistance to this antibiotic is most commonly by

Antifungal drugs usually target the cell membrane.

The rate of elimination of an antimicrobial is expressed as its

Antibiotics that affect various strains of Gram-positive bacteria and various strains of Gram-negative bacteria are called

What are two advantages of automated tests used to determine antimicrobial susceptibility?

In what clinical situation is it most appropriate to use a broad-spectrum antimicrobial?

Acyclovir is selective and low in toxicity, causing little harm to uninfected cells, because

Broad-spectrum antibiotics have minimal effect on the normal microbiota.

Which of the following groups of microorganisms produces antibiotics?

A commercial modification of the disk diffusion test is called the

Why would it be important for the Kirby-Bauer disc diffusion test to use a standard concentration (number of cells in the sample) of each of the bacterial strains being tested?

Humans and the Microbial World

The Molecules of Life

Microscopy and Cell Structure

Dynamics of Microbial Growth

Control of Microbial Growth

Microbial Metabolism: Fueling Cell Growth

The Blueprint of Life, from DNA to Protein

Bacterial Genetics

Biotechnology

Identifying and Classifying Microorganisms

The Diversity of Bacteria and Archaea

The Eukaryotic Members of the Microbial World

Viruses, Viroids, and Prions

The Innate Immune Response

The Adaptive Immune Response

Host-Microbe Interactions

Immunological Disorders

Applications of Immune Responses

Epidemiology

Respiratory System Infections

Skin Infections

Wound Infections

Digestive System Infections

Blood and Lymphatic Infections

Nervous System Infections

Genitourinary Tract Infections

Microbial Ecology

Environmental Microbiology: Treatment of Water, Wastes, and Polluted Habitats

Food Microbiology

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