Antibiotic Drug Classes

Question 1

What are the four classifications of antimicrobial drugs based on mechanism of action?

Answer 1

1. inhibit cell wall synthesis
2. inhibit protein synthesis
3. inhibit folic acid biosynthetic pathway
4. inhibit DNA/RNA synthesis

Question 2

Narrow spectrum penicillins

Answer 2

Oxacillin, Nafcillin

Question 3

Broad spectrum penicillins

Answer 3

peperacillin

Question 4

B-lactams mechanism of action is on

Answer 4

the bacterial cell wall

Question 5

Which enzyme do B lactase work to inhibit

Answer 5

transpeptidase

Question 6

By inhibiting transpeptidase, B-lactams prevent what in the structure of the cell wall synthesis?

Answer 6

Cross link of peptidoglycan molecules in bacterial cell wall to give cell wall strength

Question 7

Which bacteria are more sensitive to B-lactams?

Answer 7

gram positive bacteria

Question 8

B-lactamase inhibitors are added to some B-lactams to overcome ?

Answer 8

resistance by B-lactamase

Question 9

Clavulanic acid is added to

Answer 9

amoxicillin

Question 10

Tazobactam is added to

Answer 10

piperacillin

Question 11

Which penicillin has greater activity against gram negative and why?

Answer 11

Amino penicillin because it makes the molecule hydrophilic to cross the LPS layer easier.

Question 12

Imipenem is administered with cilastatin why?

Answer 12

To prevent renal metabolism of imipenem by inhibit of DHP (breaks down imipenem in the kidney) by cilastatin

Question 13

The structural difference between penicillin and cephalosporin is what?

Answer 13

Cephalosporin is a 6 membered ring instead of 5

Question 14

1st generation of cephalosporins are useful to treat?

Answer 14

skin infections (streptococcus or staphylococcus)

Question 15

Which drug is commonly used for surgical prophylaxis? (cephalosporin)

Answer 15

Cefazolin

Question 16

Most commonly prescribed cephalosporin for outpatient use?

Answer 16

Cephalexin (1st gener. oral drug)

Question 17

Cephalosporins are better used to treat which type of bacterial infections?

Answer 17

Gram-negative

Question 18

Which cephalosporin is used commonly in treatment of STDs?

Answer 18

Ceftriaxone

Question 19

Which drug is the drug of choice for treating pediatric meningitis?

Answer 19

Ceftriaxone (3rd gen. IV)

Question 20

Drug commonly used to treat pseudomonas infections?

Answer 20

Cefepime (3rd gener. IV)

Question 21

Inhibition of cell wall by attaching to end of peptidoglycan precursor unit (short 4/5 aa sequence called d analyl-dalanine) to lay down in matrix

Answer 21

vancomycin

Question 22

Vancomycin MOA is

Answer 22

Bacteriocidal in dividing organisms, can’t make cell wall, stops peptidoglycan synthesis

Question 23

Vancomycin is only effective against which type of organisms?

Answer 23

gram positive organisms

Question 24

Fosfomycin inhibits what?

Answer 24

first steps in synthesis of peptidoglycan

Question 25

Aminoglycoside is a

Answer 25

Protein synthesis inhibitor

Question 26

Aminoglycosides bind where?

Answer 26

to the 30S ribosomal subunit to cause proteins with incorrect amino acid sequences (low concentrations)

Question 27

What is the effect of the membrane for aminoglycosides?

Answer 27

create fissures and pores in the outer cell membrane, leakage of intracellular contents and action against protein synthesis

Question 28

Aminoglycosides are

Answer 28

bacteriocidal

Question 29

Amino glycosides are particularly effective against what bacteria

Answer 29

gram negative bacteria

Question 30

MOA for macrolides

Answer 30

binds to the 23S rRNA of the 50S subunit inhibiting peptide transferase

Question 31

Macrolides are

Answer 31

bacteriostatic

Question 32

Macrolide's are phagocytosed by

Answer 32

macrophages to allow WBC to travel to sites of infection where drug is needed

Question 33

Erythromycin and methylated nitrogen make

Answer 33

azithromycin (macrolide)

Question 34

Lincosamides MOA

Answer 34

bind to the 23S rRNA molecule of 50S RSU, inhibits peptide transferase

Question 35

Lincosamides are

Answer 35

bacteriostatic

Question 36

Example of lincosamide

Answer 36

Clindamycin

Question 37

Tetracyclines bind to what?

Answer 37

reversibly to the 16S subunit of the 30S RSU and inhibit translation, inhibits tRNA interaction

Question 38

Tetracyclines are

Answer 38

bacteriostatic

Question 39

Streptogramins bind to the

Answer 39

50S ribosomal subunit

Question 40

Which drug will bind to the same subunit as the macrolides

Answer 40

Quinupristin (inhibits polypeptide elongation and early termination of protein synthesis)

Question 41

Dalfopristin will do what to quinupristin

Answer 41

It will enhance the binding of the quinupristin at the target site

Question 42

Mupirocin does what?

Answer 42

binds and inhibits the isoleucyl transfer RNA synthetase

Question 43

Mupirocin acts against what type of bacteria and how?

Answer 43

bactericidal against gram-positive and select gram-negative, applied topically

Question 44

Mupirocin is good against what bacteria?

Answer 44

Streptococcus pyogenes, methicillin-resistant strains of Staph aureus

Question 45

Chloramphenicol binds where

Answer 45

50S subunit at peptidyltransferase site and inhibits transpeptidation reaction

Question 46

Chloramphenicol binds near site of

Answer 46

clindamycin and macrolides

Question 47

Fluoroquinolones inhibit what enzyme

Answer 47

DNA gyrase (Topo II) gram negative and Topo IV in gram positive

Question 48

What does inhibition of DNA gyros cause/

Answer 48

prevents reattachment of DNA once cut --> accumulation of DNA segments, bacteriocidal

Question 49

inhibition of Topo IV

Answer 49

interferes with separation of replicated chromosomal DNA into respective daughter cells during cell division --> halts cell division

Question 50

Rifamycin binds what

Answer 50

bacterial RNA polymerase to inhibit RNA synthesis

Question 51

Rifamycin is highly

Answer 51

lipophilic to allow it cross lipophilic membranes

Question 52

Rifamycins can act on

Answer 52

biofilms!

Question 53

Nitroimidazole-metronidazole is a

Answer 53

prodrug

Question 54

Methonidazole on aerobic bacteria

Answer 54

oxygen terminal electron acceptor --> prodrug doesn't convert to active form

Question 55

Methonidazole on anaerobic bacteria

Answer 55

Drug is effective because produces toxins and free radicals that damage DNA

Question 56

Daptomycin acts on the

Answer 56

cell wall structure in gram positive bacteria

Question 57

Daptomycin lipopepetides

Answer 57

bind to bacterial membrane to cause depolarization of membrane potential, inhibit protein, DNA, RNA synthesis --> cell death --> bactericidal against gram positive bacteria

Question 58

Pulmonary surfactant will bind to which drug to inhibit its actions?

Answer 58

daptomycin

Question 59

Treatment of pseudomembranous colitis or C. Diff associated diarrhea

Answer 59

Fidaxomicin

Question 60

Fidaxomicin

Answer 60

inhibits RNA synthesis by inhibiting bacterial RNA polymerase

Question 61

Cotrimoxazole trimethoprim and sulfamethoxazole act how?

Answer 61

inhibit the incorporation of PABA into folic acid and reduction of dihydrofolate to tetrahydrofolate

Question 62

the correct ratio of sulfamethoxazole and trimethoprim

Answer 62

20 parts sulfamethoxazole to 1 part trimethoprim

Question 63

Trimethoprim and sulfamethoxazole are good for treatment of

Answer 63

UTI uncomplicated, chronic bronchitis, infection by pneumocystic jiroveci