deck_5727627

Question 1

what makes up the 70S ribosome complex?

Answer 1

30 S subunit + 50 S subunit

Question 2

what makes up the 80S ribosome complex?

Answer 2

40S subunit + 60S subunit

Question 3

describe the 3 ribosomal binding sites for tRNA

Answer 3

A site holds AA to be added P site holds growing polypeptide chain E site
exit site for tRNA

Question 4

once the initiation complex is in place, the ___ assembles onto the ___ and the initiate proteins disassociate.

Answer 4

• large ribosomal subunit

* small subunit

Question 5

after the large ribosomal subunit assembles onto the small ribosomal subunit and the initiation proteins disassociate, what happens?

Answer 5

the ribosome is now ready to begin translation

Question 6

prokaryotic translation occurs on ___ ribosomes

Answer 6

70S

Question 7

eukaryotic translation occurs on ___ ribosomes

Answer 7

80S

Question 8

describe the main steps of translation after the initiation complex is in place and the large and small ribosomal subunits are assembled

Answer 8

• codon recognition
• peptide bond formation
• translocation
• ribosome is ready for the next aminoacyl tRNA

Question 9

what are the 4 functional targets of antimicrobial PSIs?

Answer 9

• chloramphenicol
• erythromycin (macrolides)
• tetracyclines
• streptomycin (aminoglycoside)

Question 10

___ binds to the 50S ribosomal subunit portion and inhibits formation of the peptide bond

Answer 10

chloramphenicol

Question 11

___ binds to the 50S ribosomal subunit portion, preventing translocation/movement of the ribosome along mRNA

Answer 11

erythromycin (macrolide)

Question 12

___ interfere with attachment of tRNA to the mRNA-ribosome complex

Answer 12

tetracyclines

Question 13

___ changes shape to the 30S ribosomal subunit portion, causing the code on mRNA to be read incorrectly

Answer 13

streptomycin (aminoglycoside)

Question 14

what are the 5 aminoglycosides?

Answer 14

• gentamycin
• amikacin
• tobramycin
• streptomycin
• neomycin

Question 15

what class of antimicrobials has the following mechanism of action?binds to the 30S ribosomal subunit changing its shape, which can have the following three consequences: (1) blocked initiation of mRNA translation, (2) premature termination of mRNA translation, and (3) misreading of the mRNA and incorporation of incorrect amino acids

Answer 15

aminoglycosides

Question 16

describe streptomycin

Answer 16

• aminoglycoside drug
• IM, IV administration
• oldes of the family
• high level of bacterial resistance

Question 17

describe gentramycin

Answer 17

• aminoglycoside drug
• IV preffered administration
• most commonly prescribed aminoglycoside
• used in combination with penicillins

Question 18

describe amikacin

Answer 18

• aminoglycoside drug
• IM, IV administration
• broadest spectrum of all aminoglycosides
• used for hospital acquired infections

Question 19

describe tobramycin

Answer 19

• aminoglycoside drug
• IM, IV administration
• excellent activity against pseudomonas aeruginosa

Question 20

describe neomycin

Answer 20

• aminoglycoside drug
• topical administration only
• used primarily as topical for skin infections
• neomycin enema

Question 21

what is a neomycin enema?

Answer 21

to flush and detoxify the colon and lower bowel before bowel surgery

Question 22

aminoglycosides are used primarily to treat infections caused by what class of bacteria?

Answer 22

aerobic gram negative

Question 23

the utility of aminoglycosides is limited by the occurrence of ___

Answer 23

serious toxicities

Question 24

describe the bactericidal effect of aminoglycosides

Answer 24

• concentration-dependent killing (type 1)
• mild post-antibiotic effect (PAE) once-daily dosing
• effective, reduces risk of toxicity

Question 25

describe the exceptions to daily dosing of aminoglycosides

Answer 25

administered every 8 hours for: * pregnancy * neonatal infections * bacterial endocarditis * monitor creatinine clearance and BUN

Question 26

aminoglycosides are generally given via IV or IM.  the exception is neomycin, which is given topically.  why?

Answer 26

due to nephrotoxicity

Question 27

in anuric patients, the 1/2 life of aminoglycosides can increase by how much?

Answer 27

20-40x

Question 28

with aminoglycosides, since the risk of nephrotoxicity and ototoxicity is concentration-dependent, it is crucial to do what?

Answer 28

reduce dosages, especially in patients with impaired renal function

Question 29

aminoglycosides synergize with ___ or ___

Answer 29

beta-lactams or vancomycin (when used in combination)

Question 30

all aminoglycosides have the potential to produce ___ toxicity

Answer 30

vestibular/cochlear and renal toxicity(major limitation to the clinical utility of aminoglycosides)

Question 31

ototoxicity caused by aminoglycosides may become irreversible rapidly.  the toxicity correlates with what?

Answer 31

the number of destroyed hair cells

Question 32

the frequent monitoring of what is essential during nephrotoxicity caused by aminoglycosides?

Answer 32

plasma concentrationex. BUN and serum creatinine levels

Question 33

name the 4 major adverse effects of aminoglycosides

Answer 33

* ototoxicity * nephrotoxicity * neuromuscular paralysis * contact dermatitis * accumulation in fetal plasma and amniotic fluid in utero (teratogenic)

Question 34

what 4 groups are most at risk for aminoglycoside adverse effects?

Answer 34

* elderly * impaired renal function septic patients * must adjust dose previous exposure to aminoglycosides * "functional accumulation"

Question 35

name the 4 types of tetracyclines

Answer 35

* tetracycline * doxycycline * minocycline * tigecycline

Question 36

describe the spectrum of tetracyclines

Answer 36

* broad spectrum against gram positive and negative, and atypical intracellular organisms

Question 37

which class of antimicrobials has the following mechanism of action?binds reversibly to 30S subunit of bacterial ribosome blocking access of the amino acyl-tRNA to the mRNA-ribosome complex's acceptor site

Answer 37

tetracyclines

Question 38

the mechanism of action of tetracyclines inhibits the ___ subunit to prevent attachment of the ___

Answer 38

* 30S | * aminoacyl-tRNA

Question 39

tetracyclines have a ___ action

Answer 39

bacteriostatic

Question 40

___ is often used for the treatment of acne vulgaris

Answer 40

tetracycline

Question 41

describe the cross-resistance of tetracyclines, and the exception

Answer 41

* if resistant to one TTC (tetracycline), then resistant to all TTCs * exception: tigecycline

Question 42

the oral absorption of tetracyclines is altered by what 3 things?

Answer 42

* dairy * iron supplements * antacids

Question 43

where in the body does tetracycline tend to concentrate?

Answer 43

* Caclium-hydroxyapatite teeth/bones, or tumore with high calcium content

Question 44

what are the 11 main adverse effects of tetracyclines?

Answer 44

* GI upset * disulfuram-like effect (avoid alcohol) * hepatotoxicity * headache * metallic taste * phototoxicity * vestibular problems * benign intracranial hypertension * itching in anal and genital areas * superinfections  * don't give to pregnant patients

Question 45

describe superinfections as an adverse effect of tetracyclines

Answer 45

* candida pseudomonas colitis | * diarrhea due to overgrowth of c. difficile

Question 46

what are the two main oral adverse effects of tetracyclines?

Answer 46

* hairy tongue | * deposition in bone and primary dentition

Question 47

what are the contraindications for tetracyclines?

Answer 47

* pregnant patients * breastfeeding patients * children <8 yrs * inpatients with liver and renal disease

Question 48

describe the spectrum of bacteria tigecycline acts against

Answer 48

same as doxycyline and other TTCs plus activity against: * MRSA * multidrug resistant s. pneumoniae * vancomycin resistant enterococci * some anaerobes

Question 49

___ was developed to overcome TTC-resistance in complicated skin, soft tissue, and intra-abdominal infections

Answer 49

tigecycline

Question 50

how is tigecycline administered?

Answer 50

IV

Question 51

what are the adverse effects of tigecycline?

Answer 51

similar to other TTCs, including teeth and bones

Question 52

what are the 3 macrolides?

Answer 52

erythromycin, clarithromycin, azithromycin

Question 53

which antimicrobials has the following mechanism of action?binds irreversibly to 50S subunit of bacterial ribosome to inhibit the translocation step of protein synthesis

Answer 53

macrolides (ketolides)

Question 54

describe the spectrum of action of macrolides

Answer 54

gram positive and negative, and atypical bacteria (cross resistance within class)

Question 55

what are considered the safest antimicrobials?

Answer 55

macrolides

Question 56

the following clinical uses describe what antimicrobial?2nd line agents for skin and soft tissue infections not due to MRSA; frequently used for URIs and community acquired pneumonia

Answer 56

macrolides

Question 57

which macrolide is often used in patients allergic to penicillin?

Answer 57

erythromycin

Question 58

erythromycin has largely been replaced by ___ and ___ for community acquired penumonia

Answer 58

clarithromycin and azithromycin

Question 59

describe the clinical uses of azythromycin

Answer 59

* "z-pak" | * azithromycin is preferred therapy for urethritis caused by chlamydia

Question 60

which of the macrolides has the longest 1/2 life and volume of distribution in its class?

Answer 60

azithromycin