Antimicrobials

Question 1

penicillin G, penicillin V

Answer 1

narrow-spectrum B-lactams

simple penicillin

penicillin V is orally active - used to treat oropharyngeal infections

Question 2

Mechanism for B-lactam cell wall inhibitors

Answer 2

looks like Dala-Dala, binds PBPs (transpepsidases), blocks peptidoglycan cross-linking

Question 3

Adverse affects of B-lactam cell wall inhibitors

Answer 3

allergic reactions, including anaphylaxis, rashes, nephritis

Question 4

adverse effects of carbapenems

Answer 4

increases risk of seizure

Question 5

extended spectrum penicillins

Answer 5

amoxicillin

Question 6

static

Answer 6

concentration that inhibits growth is much less than concentration that kills

Question 7

cidal

Answer 7

concentration that inhibits growth is similar to concentration that kills

Question 8

examples of tidal drug classes

Answer 8

B-lactams, ahminoglycosides, fluoroguinolones, metronidazole, vancomycin, streptogramins, daptomycin

Question 9

examples of static drug classes

Answer 9

clindamycin, macrolides, tetracyclines, sulfonamides, trimethoprim

Question 10

superinfection

Answer 10

disruption of flora by antimicrobial allows single microorganism to overgrow and cause pathology - highest risk is with broad-spectrum antibiotics

Question 11

mechanism of B-lactams

Answer 11

inhibit bacterial cell wall synthesis

Question 12

B-lactamases

Answer 12

catalyze hydrolysis of B-lactam ring of B-lactam antibiotics causing inactivation.

formation by pathogens creates resistance

Question 13

B-lactamase inhibitors

Answer 13

clavulanic acid, sulbactam, tazobactam

used in combination with penicillins to prevent their inactivation

Question 14

naficillin

Answer 14

very narrow spectrum lactamase resistant penicillin

Question 15

piperacillin

Answer 15

anti-pseudomonal B-lactam

used w/ penicillinase inhibitors

Question 16

cefazolin, cephalexin

Answer 16

1st generation cephalsporins

B-lactams

cephalexin is orally active

Question 17

cefuroxime

Answer 17

B-lactam

2nd generation cephalosporin

orally active

extended gram (-) coverage

Question 18

ceftriaxone

Answer 18

B-lactam

3rd generation cephalosporin

increased activity against gram (-) organisms resistant to other B-lactam drugs - used for serious infections

can penetrate the BBB

Question 19

cefepime

Answer 19

B-lactam

4th generation cephalosporin

more active against pseudomonas

Question 20

ceftaroline

Answer 20

B-lactam

5th generation cephalosporin

active against MRSA

Question 21

meropenem

Answer 21

B-lactam

carbapenem

low susceptibility to B-lactamases

adverse effects: increased seizure risk

Question 22

aztreonam

Answer 22

B-lactam

monobactam

active only against gram (-) bacteria

Question 23

vancomycin: mechanism, adverse effects, uses, mode of resistance

Answer 23

non-B-lactam cell wall inhibitor

mechanism: binds Dala/Dala and blocks transglycosylation and elongation of the peptidoglycan chain

adverse effects: red man syndrome

uses: MRSA, C.Diff
resistance: via altered peptidoglycan - Dala-Dlac

Question 24

chloramphenicol

Answer 24

macrolide

adverse effects: bone marrow depression, aplastic anemia

uses: severe salmonella, Tx of pneumococcal and miningococcal meningitis and B-lactam sensitive people, also topical abx

Question 25

azithromycin

Answer 25

macrolide adverse effects: GI upset, prolonged QT

Question 26

clindamycin

Answer 26

macrolide adverse effects: associated with C.diff MRSA active

Question 27

linezolid

Answer 27

protein synthesis inhibitor - oxazolidinone mechanism: binds to a unique site located on the 23S ribosomal RNA of the 50S ribosomal subunit adverse effects: bone marrow supression, serotonin syndrome in pts using SSRIs uses: should be reserved for treatment of infections caused by multidrug-resistant gram-positive bacteria

Question 28

gentamicin

Answer 28

protein synthesis inhibitor - aminoglycoside mechanism: binds to 30S subunit irreversibly adverse effects: nephro-oto-neuro toxicity

Question 29

doxycycline

Answer 29

protein synthesis inhibitor - binds to 30S subunit reversibly adverse effects: incorporated into teeth/bones, photosensitivity. doxy and tigecycline MRSA active, doxy Tx for malaria

Question 30

sulfamethoxazole

Answer 30

folate pathway inhibitor - antimetabolite of PABA that acts as competitive inhibitor or substrate for dihydropteroate synthase in folic acid synthesis. adverse effects: hypersensitivity reactions. active against MRSA used with trimethoprim

Question 31

sulfamethoxazole

Answer 31

folate pathway inhibitor - antimetabolite of PABA that acts as competitive inhibitor or substrate for dihydropteroate synthase in folic acid synthesis. adverse effects: hypersensitivity reactions (including Stevens-Johnson syndrome, but rare). active against MRSA used with trimethoprim

Question 32

ciprofloxacin

Answer 32

topo inhibitor - fluoroquinolone. mechanism: interfere with bacterial DNA synthesis by inhibiting topoisomerase II (DNA gyrase) adverse effects: tendonitis, tendon rupture, peripheral neuropathy, CNS effects, porolonged QT. moxi, levo, gemi more active on S. pneumoniae than cipro.

Question 33

daptomycin

Answer 33

membrane disruptor mechanism: inserts itself into membranes and causes leakage of small ions/molecules. adverse effects: myopathy inactivated by pulmonary surfactants, MRSA active

Question 34

metronidazole

Answer 34

mechanism: forms cytotoxic products that interfere with bacterial nucleic acid synthesis. adverse effects: headache, peripheral neuropathy, alcohol sensitivity uses: anaerobies, antiprotozoal, giardia

Question 35

TB drugs

Answer 35

rifampin, isoniazid, pyrazinamide, ethambutol