Antibacterial Agents III

Question 1

The three macrolides are ___________.

Answer 1

azithromycin, clarithromycin, and erythromycin

Question 2

What are the important considerations for hepatically metabolized drugs?

Answer 2

(1) drug-drug interactions; (2) genetic differences in metabolism; and (3) potential for hepatotoxicity

Question 3

All of the protein-synthesis inhibitors are bacteriostatic except __________.

Answer 3

the aminoglycosides, which irreversibly bind to the 30S subunit

Question 4

The tetracyclines bind to the _________, as do aminoglycosides.

Answer 4

30S subunit

Question 5

Chloramphenicol and the macrolides bind to the ____________.

Answer 5

50S subunit

Question 6

Resistance to tetracycline is commonly accomplished by _________.

Answer 6

acquisition of DNA that expresses proteins for efflux pumps

Question 7

Tetracycline absorption is impaired by _________.

Answer 7

milk products, Al3+, Ca2+, Mg2+, and Fe2+

Question 8

Chemically, macrolides are __________.

Answer 8

weak bases that are more active at alkaline pHs

Question 9

Drug inactivation does not occur with __________.

Answer 9

macrolides

Question 10

Resistance to macrolides can occur by _________.

Answer 10

drug efflux or methylation of the 50S subunit

Question 11

Which macrolide should be taken on an empty stomach?

Answer 11

Azithromycin

Question 12

Azithromycin and erythromycin cannot reach the _______, but they can pass to the ________.

Answer 12

CSF; placenta

Question 13

Which macrolide can be dosed once daily?

Answer 13

Azithromycin

Question 14

Macrolides can kill ____________.

Answer 14

Gram-positive cocci (except enterococci), many Gram-negative bacteria (H. influenzae, Neisseria, Leionella, Bortadella), and atypical bacteria

Question 15

What are the three ways bacteria become resistant to tetracyclines?

Answer 15

Decreased entry, increased efflux, and modified protein target (30S)

Question 16

Tetracyclines are best absorbed on _________ stomach.

Answer 16

an empty

Question 17

Tetracyclines work great for everything except ___________.

Answer 17

Enterococci, Clostridia, Pseudomonas, and H. influenzae

Question 18

Vibrio cholerae is a ___________.

Answer 18

Gram-negative bacillus

Question 19

Other than macrolides, _________ also binds to the 50S subunit.

Answer 19

clindamycin

Question 20

Clindamycin mostly works just on __________, but also works on _________.

Answer 20

Gram-positive cocci (except enterococci); Bacteroides fragilis

Question 21

List the aminoglycosides.

Answer 21

Streptomycin, Tobramycin, Gentamicin, Amikacin, Kanamycin, and Neomycin

Question 22

Aminoglycosides are ________ soluble and more active at ___________.

Answer 22

water (hence, they do not penetrate tissues well); alkaline pH

Question 23

The three ways bacteria become resistant to aminoglycosides are __________.

Answer 23

decreased entry, modified drug target, and enzymatic drug modification

Question 24

Because they are polar and cationic, _____ are not well absorbed orally.

Answer 24

aminoglycosides

Question 25

Aminoglycosides work well against __________.

Answer 25

Gram-positive cocci (except enterococci) and Gram-negative rods (except H. influenzae); they are not effective against atypical or anaerobic bacteria

Question 26

Again, aminoglycosides are very toxic to the __________.

Answer 26

kidneys and inner ears

Question 27

Because it is so lipid soluble, _________ is rapidly absorbed and well distributed to all tissues.

Answer 27

chloramphenicol

Question 28

Chloramphenicol is best at treating _________.

Answer 28

Gram-negative bacteria, anaerobes, and atypical bacteria

Question 29

Toxic effects of chloramphenicol include ___________.

Answer 29

grey baby syndrome and bone marrow toxicity

Question 30

_________ also inhibit the 50S subunit, but because they do so at a different site, no cross-resistance has been observed.

Answer 30

Linezolids

Question 31

Clarithromycin has a ________ duration than erythromycin.

Answer 31

longer

Question 32

How would you treat community-acquired pneumonia in a healthy person, a person who had had abx within the past three months, and a person in the ICU?

Answer 32

Healthy = doxycycline or a macrolides; previous abx = fluoroquinolone or macrolide + beta-lactam; and ICU = pip/taz + fluoroquinolone or vancomycin

Question 33

The only drug that treats Lyme disease is __________.

Answer 33

doxycycline

Question 34

Clindamycin can cause ___________.

Answer 34

pseudomembranous coitis

Question 35

Iron supplements decrease the bioavailability of ____________.

Answer 35

tetracyclines

Question 36

The cyclines are __________.

Answer 36

teratogenic