Antibacterial Agents II

Question 1

Structurally, penicillin is a __________.

Answer 1

beta-lactam ring

Question 2

There are three stages of bacterial cell wall synthesis that can be targeted by antibiotics. What are they?

Answer 2

(1) synthesis of cell wall parts in the cytosol; (2) polymerization of subunits at the cell membrane; and (3) cross linking of peptidoglycans at the cell wall

Question 3

What antibiotics target stage 1 of cell-wall synthesis?

Answer 3

Fosfomycin and cycloserine

Question 4

What antibiotics target stage 2 of cell-wall synthesis?

Answer 4

Bacitracin and vancomycin

Question 5

What antibiotics target stage 3 of cell-wall synthesis?

Answer 5

Penicillins and cephalosporins

Question 6

Beta-lactamases are _____________.

Answer 6

a generic term for enzymes that degrade beta-lactam rings; they are not one specific enzyme

Question 7

Methicillin resistance occurs by ___________.

Answer 7

alterations in penicillin-binding proteins

Question 8

Penicillin is ________ at neutral pH and thus does not ___________.

Answer 8

ionized; enter cells or cross basement membranes well

Question 9

Penicillins are __________ excreted.

Answer 9

renally

Question 10

Piperacillin and ticarcillin are great for _________, but they must be administered __________.

Answer 10

killing pseudomonas and anaerobic bacteria; parenterally

Question 11

Name three beta-lactamase inhibitors.

Answer 11

Sulbactam, tazobactam (combined with piperacilln to become Zosyn), and clavulanic acid (combined with amoxicillin to become Augmentin)

Question 12

What antibiotic is used to treat non-invasive streptococci infections?

Answer 12

Penicillin G

Question 13

What drug should be given to those with enterococci-associated bacteremia and meningitis?

Answer 13

Penicillin G and ampicillin

Question 14

Some adverse reactions to penicillins are ___________.

Answer 14

diarrhea (which is common), seizures, and encephalopathy

Question 15

There is __________ reactivity between penicillins and cephalosporins, so if a patient has a sensitivity reaction to penicillin, then _________.

Answer 15

some; do not give cephalosporins (choose something totally unrelated, like a macrolide)

Question 16

List the five categories of cell-wall inhibitors.

Answer 16

Vancomycin, penicillin, cephalosporins, carpapenems, and monobactams

Question 17

Substitution at the R group can __________ penicillins.

Answer 17

(1) increase stability in the GI tract; (2) decrease renal excretion; (3) minimize bacterial resistance; and (4) increase bacterial susceptibility

Question 18

Penicillinase is transferred via ________.

Answer 18

plasmids

Question 19

Beta-lactamase is a generic term for __________.

Answer 19

enzymes that degrade penicillins and cephalosporins

Question 20

MRSA is resistant by ____________.

Answer 20

altering its protein target (PBP2a)

Question 21

Penicillins are _________ from intramuscular sites.

Answer 21

rapidly absorbed (because it is a neutral environment)

Question 22

Penicillins penetrate tissues ________.

Answer 22

poorly

Question 23

What are some characteristics of penicillin G?

Answer 23

It is the proto-typical penicillin; former antibiotic of choice, but now limited to hospitalized patients; given parenterally; susceptible to penicillinase.

Question 24

Compared to penicillin G, Penicillin V is ________.

Answer 24

less effective, but better absorbed orally

Question 25

What are the penicillinase-resistant penicillin drugs?

Answer 25

Nafcillin, oxacillin, veracillin, cloxacillin, and dicloxacillin

Question 26

The penicillinase-resistant drugs are ________.

Answer 26

generally less potent than penicillin G and narrow-spectrum

Question 27

How are extended spectrum penicillins different?

Answer 27

They are more hydrophilic (due to an extra amino or carboxyl group) and can thus pass through porins in Gram-negative bacteria more easily.

Question 28

Most penicillins only work against _________; the exceptions are ________.

Answer 28

Gram-positive bacteria; amoxicillin, ampicillin, ticarcillin, and piperacillin, which work on some Gram-negative rods

Question 29

Amoxicillin is not _________, but can be _________.

Answer 29

resistant to penicillinases; administered with a beta-lactamase inhibitor (such as clavulanic acid)

Question 30

The only penicillins that work against Bacteroides fragilis and Pseudomonas are __________, but they have to be administered ___________.

Answer 30

Ticarcillin and Piperacillin; through an IV

Question 31

There are three main beta-lactamase inhibitors: __________.

Answer 31

clavulanic acid, sulbactam, and tazaobactam

Question 32

Of Gram-positive cocci, cephalosporins do not kill ________.

Answer 32

enterococcus (including VRE)

Question 33

Haemophilus influenzae is known to cause __________.

Answer 33

pneumonia, sinusitis, otitis media, and menigitis

Question 34

Treat Treponema pallidum with (the spirochete that causes syphilis) with _______.

Answer 34

penicillin G

Question 35

The only drug that kills Borrelia burgdorferi (Lyme disease) is ________.

Answer 35

amoxicillin

Question 36

Haptens are ___________.

Answer 36

small molecules that attach to larger molecules to form antigens

Question 37

Vancomycin is administered ________.

Answer 37

parenterally, except in cases of Clostridial GI infections

Question 38

What organisms does vancomycin kill?

Answer 38

All Gram-positive cocci (except VRE) and Clostridia

Question 39

What is the main concern for adverse reactions with vancomycin treatment?

Answer 39

Ototoxicity, nephrotoxicity, and Red Man syndrome

Question 40

Daptomycin targets _______ and can be used to kill ________, but it has restricted use.

Answer 40

cell membranes; MRSA, VRSA, and VRE

Question 41

The lipoglycopeptides are ___________; they target __________; they should only be used in ___________.

Answer 41

oritavancin, dalbavancin, and telavancin; they same step as vancomycin, and so kill Gram-positive bacteria; patients with allergies to other drugs or infections with resistant strains

Question 42

________ is the only cephalosporin that can kill MRSA.

Answer 42

Cefepime

Question 43

Cephalosporins have a similar range of killing as amoxicillin, but they can't kill ________.

Answer 43

Enterococci

Question 44

Keflex is ___________.

Answer 44

an orally administered, first-generation cephalosporin called cephalexin

Question 45

Rocephin is __________, and it is unique for its ability to kill __________.

Answer 45

ceftriaxone; Neisseria gonorrhoeae

Question 46

The carbapenems are bactericidal to everything except ___________.

Answer 46

E. faecium, VRE, Clostridia, and atypical bacteria

Question 47

Monobactams only kill ___________.

Answer 47

Gram-negative aerobic bacteria

Question 48

The best antibiotics for Gram-negative Neisseria are ____________.

Answer 48

3rd-generation cephalosporins (ceftriaxone and cefotaxime)

Question 49

Like piperacillin and ticarcillin, second generation cephalosporins (cefaclor and cefuroxime) are active against __________.

Answer 49

Bacteroides fragilis

Question 50

In addition to cefepime and ceftaroline, ________ all also kill MRSA.

Answer 50

vancomycin, clindamycin, tetracyclines, and macrolides