Exam 1 - (CH 12) Antibacterial Mechanisms of Action and Bacterial Resistance Mechanisms Textbook Review Questions

Question 1

Which of the following antibiotics is a β-lactam?
A. Rifampin
B. Lincosamides
C. Chloramphenicol
D. Carbapenems

Answer 1

D. Carbapenems

Question 2

Trimethoprim prevents
A. recycling of folate coenzymes required for DNA biosynthesis.
B. decatenation at the end of bacterial DNA replication.
C. the transpeptidation step in cell wall biosynthesis.
D. RNA polymerase β subunit from continuing RNA chain elongation.

Answer 2

A. recycling of folate coenzymes required for DNA biosynthesis.

Question 3

Which antibiotic class targets the 50S ribosomal subunit?
A. Aminoglycosides
B. Tetracyclines
C. Macrolides
D. Teicoplanin

Answer 3

C. Macrolides

Question 4

Tetracyclines
A. are bacteriostatic β-lactams.
B. are only used to treat pseudomonad infections.
C. allow mRNA translation but inhibit peptide elongation.
D. interfere with DNA transcription by binding the 50S subunit of 16S RNA.

Answer 4

C. allow mRNA translation but inhibit peptide elongation.

Question 5

An example of a macrolide is
A. vancomycin.
B. clarithromycin.
C. telavancin.
D. sulfamethoxazole.

Answer 5

B. clarithromycin.

Question 6

The New Delhi metallo-β-lactamase-1 hydrolyzes all of the following except
A. penicillins.
B. cephalosporins.
C. aztreonam.
D. carbapenems.

Answer 6

C. aztreonam.

Question 7

Which of the following are used to enhance the range by preventing the degradation of β-lactam antibiotics?
A. MICs
B. AACs
C. Vat(E)s
D. BLIs

Answer 7

D. BLIs

Question 8

Plasmid NR1 isolated from this organism is the archetype plasmid responsible for dissemination of Tns and plasmid antimicrobial resistance.
A. Klebsiella pneumoniae
B. Enterobacter aerogenes
C. Streptomyces spectabilis
D. Shigella flexneri

Answer 8

D. Shigella flexneri

Question 9

Which of the following is a β-lactamase inhibitor with a β-lactam core?
A. Avibactam
B. Ceftazidime
C. Tazobactam
D. Aztreonam

Answer 9

C. Tazobactam

Question 10

Antibiotics can be:

a. Natural molecules.
b. Synthetic molecules.
c. Semisynthetic molecules.
d. All of the above.

Answer 10

d. All of the above.

Question 11

Which of the listed antimicrobials act on cell wall biosynthesis?

a. β-Lactams and glycopeptides
b. Tetracycline and streptomycin
c. Macrolides and phenicols
d. Fluoroquinolone and sulfamethoxazole

Answer 11

a. β-Lactams and glycopeptides

Question 12

Which of the antimicrobials are new analogs of older classes?

a. Glycylcycline from tetracyclines
b. Ketolides from macrolides
c. Fluoroquinolone from glycopeptides
d. Both a and c
e. Both a and b

Answer 12

e. Both a and b

Question 13

The most commonly used inhibitors of cell wall biosynthesis act on:

a. Transportation of lipid-bound precursors across the cytoplasmic membranes.
b. Insertion of glycan units into the cell wall.
c. Transpeptidation linking and maturation.
d. Synthesis of precursors in the cytoplasm.
e. Both b and c

Answer 13

e. Both b and c

Question 14

Which of the antimicrobial classes include semisynthetic and natural derivatives?

a. Glycopeptides
b. Aminoglycosides
c. β-Lactams
d. Fluoroquinolones
e. All except d

Answer 14

e. All except d

Question 15

Microorganisms can exhibit antimicrobial resistance by which of the following mechanisms?

a. Intrinsic
b. Acquired
c. Both
d. Neither

Answer 15

c. Both

Question 16

Which mechanisms of antimicrobial resistance are intrinsic and acquired?

a. Efflux
b. Enzymatic
c. Biofilm
d. Acquisition of new targets
e. Both a and b

Answer 16

e. Both a and b

Question 17

Plasmids can contain which of the following?

a. Transposons
b. Insertion sequences
c. Integron cassettes
d. All of the above
e. Both a and c

Answer 17

d. All of the above

Question 18

Transposons do not contain which of the following?

a. Cytoplasmic membranes
b. Transposase
c. Excision protein genes
d. Antibiotic resistance determinants
e. Conjugative functions

Answer 18

a. Cytoplasmic membranes

Question 19

Which of the following characteristics apply to efflux pumps?

a. They are found in gram-positive and gram-negative bacteria.
b. They are transporter proteins.
c. They have single or multiple substrates.
d. Both a and c.
e. All of the above.

Answer 19

e. All of the above.

Question 20

Which of the following does not apply to antimicrobial resistance caused by target site modification?

a. Chromosomal mutation of target site
b. Quinolone resistance– determining region
c. SCCmec
d. Erythromycin-resistant methylase

Answer 20

c. SCCmec

Question 21

Enzymatic modification of aminoglycosides is not caused by which of the following?

a. N-acetylation
b. Dimethylation
c. O-phosphorylation
d. O-adenylation

Answer 21

b. Dimethylation

Question 22

Which of the following is not a characteristic of integrons?

a. Potentially mobile element
b. Gene cassettes
c. 59-bp element
d. Peptidoglycan

Answer 22

d. Peptidoglycan

Question 23

Serine-based β-lactamases appear to have evolved from the penicillin-binding proteins of bacteria. True or false?

Answer 23

True

Question 24

Which of the following is a non– β-lactam β-lactamase inhibitor?

a. Ticarcillin
b. Avibactam
c. Clavulanate
d. Sulbactam

Answer 24

b. Avibactam

Question 25

Points to Remember

Answer 25

■ Although resistance to antimicrobial agents may be genetically intrinsic or acquired, both types can be found in the same pathogen.
■ β-Lactam antibiotics, which work by inhibiting cell wall synthesis, contain a four-member ring and include the penicillins, cephalosporins, monobactams, and carbapenems.
■ The quinolones interfere with DNA replication by targeting DNA gyrases and topoisomerases.
■ Protein inhibitors include aminoglycosides, tetracyclines, macrolides, streptogramins, chloramphenicol, and linezolid.
■ Impermeability and efflux mechanism of resistance can produce multidrug-resistant phenotypes.
■ A single organism may acquire multiple mechanisms of resistance, including different mechanisms of conferring resistance to the same compound.
■ Antimicrobial mechanisms of resistance and their dissemination are not static processes.
■ Nanoparticles are being used to deliver various drugs, including antimicrobial agents, into tissue.