Antibacterial Agents I Flashcards

1
Q

To choose a good antibiotic, pick the most ________ and least _________.

A

most effective and specific; toxic

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2
Q

List some of the broad categories of antibacterial drugs.

A

Anti-cell wall synthesis, bacterial protein inhibitors, folic acid metabolism inhibitors, and bacterial transcription inhibitors

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3
Q

What enzymes are sufficiently different in bacteria to allow for targeting?

A

DNA gyrase (whereas eukaryotes have topoisomerase), and the 30S and 50S subunits of bacterial rRNA

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4
Q

What are the methods by which bacteria become resistant to drugs?

A

Expressing efflux pumps (to decrease the intracellular concentration), developing enzymatic degradation (such as beta-lactamase), bypassing the targeted pathway, decreasing entry, or altering the targeted receptor

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5
Q

Bacteriostatic agents ___________, while bactericidal agents ____________.

A

stop bacterial growth; kill bacteria

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6
Q

Bactericidal drugs are required in ___________.

A

infections of immune-privileged sites (such as the CNS), immunocompromised patients,

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7
Q

The advantages of oral antibiotics are ___________; the disadvantages are _________.

A

cost, convenience, and patient acceptance; GI upset, lack of absorption, and not possible in NPO patients

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8
Q

The advantages of IV antibiotic administration are that _________; the disadvantages are ___________.

A

it is required for some drugs and the bioavailability is more predictable; that it requirement for strict aseptic conditions, it is expensive, and greater provider training is needed

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9
Q

What anatomical site does clindamycin preferentially target?

A

Bones, so it is good for treatment of osteomyelitis

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10
Q

___________ is a good antibiotic for urinary tract infections, because it gets rapidly excreted in the urine.

A

Nitrofurantoin

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11
Q

Tetracycline lodges in the _________, where it _______.

A

gingiva and sebum; is good at targeting oral infections and acne, but has the downside of binding to Ca2++ and discoloring teeth

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12
Q

Again, the important formula for drugs that are renally excreted it __________.

A

(maintenance dose / dosing intervals) = (steady state serum concentration x clearance)
MD/tau = Cpss x Cl

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13
Q

For hepatically metabolized antibiotics, ______________.

A

there is no lab indicator of metabolism, so avoid drugs that are hepatically metabolized in patients with liver dysfunction

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14
Q

Bacteroides fragilis is a __________.

A

Gram-negative rod

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15
Q

Fluoroquinolones target _________.

A

DNA gyrase

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16
Q

Metronidazole targets ___________.

A

DNA synthesis, as does nitrofurantoin

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17
Q

Bacteria must _________ folate, while eukaryotes can ___________.

A

intracellularly synthesize; take it in from the environment

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18
Q

Many antibiotics cannot cross the outer membrane of ____________.

A

Pseudomonas aeruginosa

19
Q

Explain the differences between conjugation, transduction, and transformation.

A

Conjugation is bacterial exchange of plasmids; transduction is bacteriophage-mediated DNA transfer; and transformation is uptake of free DNA from the environment

20
Q

Give an example of alternative resistant metabolic pathway.

A

Bacteria overproduce thymine and become resistant

21
Q

What three drugs/classes of drugs are susceptible to bacteria developing resistance by efflux pumps?

A

Tetracyclines, fluoroquinolones, and macrolides

22
Q

The bacteriostatic drugs usually target ________.

A

metabolic pathways or protein synthesis

23
Q

The batericidal drugs ____________.

A

target cell walls, cell membranes, or DNA

24
Q

Antibiotics that are supposed to be taken on an empty stomach are _________.

A

susceptible to the acid that is present when we eat food

25
The antibiotics that readily enter the CSF are __________.
(cephalopods readily try chlorinated soup) cephalosporins (3rd/4th), rifampin, trimethoprim, chloramphenicol, and sulfonamides
26
The antibiotics that enter the CSF with inflammation are ______________.
Penicillins, vancomycin, ciprofloxacin, and tetracycline
27
Aminoglycosides are the most toxic to the _________.
inner ears and renal cells
28
Antibiotics that have a post-antibiotic effect are ____________.
aminoglycosides and fluoroquinolones
29
Narrow spectrum antibiotics target _________.
either Gram negative or Gram positive
30
Extended spectrum antibiotics target ___________.
Gram negative and Gram positive
31
Broad spectrum antibiotics target ___________.
Gram negative, Gram positive, and atypical bacteria
32
Trimethoprim and sulfonamides are _________.
folic acid synthesis inhibitors
33
_________ and _________ are evaded by bacteria that develop changes in the 50S ribosome subunit.
Erythromycin and clindamycin
34
_______ attacks the peptidoglycan side chain.
Vancomycin
35
DNA gyrase resistance occurs in ___________.
S. aureus and P. aeruginosa (to fluoroquinolone)
36
Strep pneumoniae becomes resistant to beta-lactams by __________.
modification of drug target
37
Macrolides get concentrated in the _________.
pulmonary cells
38
The hepatically metabolized drugs are __________.
DQ CRIMES (doxycycline, quinolones, clindamycin, rifampin, isoniazid, metronidazole, erythromycin-like (i.e., macrolides), and sulfonamides
39
__________ is a CYP inducer.
Rifampin
40
These three drugs work best when they are above their MIC for a long time: ________.
macrolides, beta-lactams, and vancomycin
41
Fluoroquinolones include ________.
levofloxacin
42
_______ is an aminoglycoside.
Tobramycin
43
When would you recommend a combination therapy?
For mixed infections (commonly intraabdominal), to prevent the emergence of drug resistant strains (AIDS patients with TB), and to obtain a synergistic effect