Antibacterial Agents Flashcards

1
Q

Penicillins used in combination with tetracyclines produce additive or antagonistic effects?

A

antagonistic effects

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2
Q

Which antimicrobial agents act through inhibition of bacterial cell-wall synthesis?

A

penicillins, cephalosporins, imipenem/ meropenem, aztreonam, vancomycin

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3
Q

Which antimicrobial agents inhibit bacterial protein synthesis?

A

aminoglycosides, chloramphenicol, macrolides, tetracyclines, streptogramins, linezolid

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4
Q

What antimicrobials act through the inhibition of nucleic acid synthesis?

A

fluoroquinolone, rifampin

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5
Q

What antimicrobials act through inhibition of folic acid synthesis?

A

sulfonamides, trimethoprim, pyrimethamine

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6
Q

Primary mechanism of resistance for pens and cephalosporins?

A

production of beta-lactamases, which cleave the beta-lactam ring structure; change in penicillin-binding proteins; change in porins

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7
Q

Primary mechanisms of resistance to aminoglycosides?

A

formation of enzymes that inactivate drugs

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8
Q

Primary mechanism of resistance to macrolides?

A

formation of methyltransferases that alter drug binding sites of 50S ribosomal subunit, and active transport out of cells.

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9
Q

Primary mechanism of resistance to tetracycline drugs?

A

increased activity of transport systems that “pump” drugs out of the cell

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10
Q

Primary mechanism of resistance to sulfonamide drugs?

A

change in sensitivity to inhibition of target enzyme;
increased formation of PABA;
use of exogenous folic acid

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11
Q

What are the primary mechanisms of resistance in evading fluoroquinolone action?

A

change in sensitivity to inhibition of target enzymes;
increased acitivity of transport systems that promote drug efflux

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12
Q

What are primary mechanisms of microbials when trying to confer resistance in response to treatment with chloramphenicol?

A

formation of inactivating acetyltransferases

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13
Q

PBP stands for what?

A

penicillin binding proteins

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14
Q

Penicillin MOA

A

pens interact with cytoplasmic membrane binding proteins PBPs to inhibit transpeptidation involved in cross-linking the final steps in cell-wall synthesis

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15
Q

What are the drugs considered antistaph pens?

A

nafcillin
oxacillin
methicillin

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16
Q

Are antistaph pens beta lactamase sensitive or resistant?

A

resistant

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17
Q

What spectrum of organisms are antistaph pens effective against?

A

very narrow: staphylococci (not MRSA)

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18
Q

Name the natural Pens and what organisms the are useful against?

A

Pen G and Pen V

Narrow spectrum:
streptococci, pneumococci, treponema

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19
Q

Are natural pens beta lactamase resistant or sensitive?

A

beta lactam sensitive

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20
Q

Name some aminopenicillin drugs, their spectrum and organisms they are useful against?

A

Amoxicillin
Ampicillin

Broad spectrum

Gram (+) cocci, Listeria, E. coli, Borrelia, H. pylori

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21
Q

Are aminopenicillins beta lactase sensitive or resistant?

A

sensitive

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22
Q

What is the spectrum of action for antipseudomonal penicillins?

A

very broad

gram (+) cocci, gram (-) rods, pseudomonas

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23
Q

Are antipseudomonal pens beta lactamase sensitive or resistant?

A

sensitive

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24
Q

Which drugs act by enhancing the activity of pens because they inhibit betalactamase?

A

clavulanic acid, sulbactam

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25
Q

Pens have synergistic effects with what drugs to act against pseudomanal and enterococcal species?

A

aminoglycosides

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26
Q

Which HSR is IgE mediated: rapid onset; anaphylaxis, angioedema, laryngospasm?

A

Type I HSR

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27
Q

Which HSR is IgM and IgG antibody fixed to cells; vasculitis, neutropenia, positive Coombs test?

A

HSR II

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28
Q

Which HSR is linked to immune complex formation, vasculitis, serum sickness, interstitial nephritis?

A

HSR III

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29
Q

Which HSR is linked to T-cell mediated urticarial and maculopapular rashes, SJS?

A

HSR IV

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30
Q

What is a S/E reaction that is evidenced with use of pens when treating syphillis?

A

Jarisch-Herxheimer rxn

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31
Q

Ampicillin is mostly excreted by which organ?

A

kidney

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32
Q

Nafcillin and oxacillin are largely eliminated where?

A

in the bile

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33
Q

MOA and resistance of cephalosporins?

A

similar to pens

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34
Q

Name the 1st generation cephalosporins?

A

cefazolin, cephalexin

ph 1st

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35
Q

What are the spectrum of organisms 1st generation cephalosporins can treat?

A

gram-positive cocci (not MRSA), E. coli, Klebsiella pneumoniae, and some proteus specieis

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36
Q

Indication for use of many 1st generation cephalosporins?

A

surgical prohylaxis

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37
Q

Name some second generation cephaloposporins.

A

cefotetan, cefaclor, cefuroxime, cefoxitin

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38
Q

What spectrum of microbials can second generation cephalosporins act on?

A

more gram neg coverage including some aneaerobes

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39
Q

Name some third gerneration cephalosporins.

A

ceftriaxzone (IM) and cefotaxime (parenteral), cefdinir and cefixime (oral)

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40
Q

What is the spectrum of antibiotic that third generation cephalosporins are useful against?

A

all of the above covered organisms by previous generations, bacteria resistant to other beta lactams,

gram positive and gram negative cocci (Neisseria gonorrhea) plus many gram - rods

41
Q

In comparison to 1st and 2nd cephalosporins can 3rd gen cross the CNS?

A

yes

42
Q

Can fourth generation cephalosporins cross the CNS?

A

yes

43
Q

Are most fourth generation cephalosporins resistant to beta-lactamases?

A

yes

44
Q

Name a fourth generation cephalosporin.

A

cefepime (IV)

45
Q

Probenecid can block active tubular secretion of which antimicrobials mainly?

A

pens and cephalosporin

46
Q

Because there is cross-allergenicity between pens and cephalosporins what are other antimicrobial agents that suggested instead?

A

consider macrolides for gram positive organisms
consider aztreonam for gram negative rods

47
Q

Imipenem and meropenem MOA?

A

same as pens and cephalosporins

48
Q

Is meropenem resistant to beta-lactamase?

A

yes

49
Q

Spectrum of drug coverage for imipenem and meropenem?

A

gram + cocci, gram - rods and anaerobes

50
Q

What drug inhibits imipenems metabolism to a nephrotoxic metabolite? What is this drugs MOA?

A

cilastatin; a renal dehydropeptidase inhibitor

51
Q

Use for Aztreonam? also ROA?

A

IV drug mainly active vs gram negative rods

52
Q

MOA of vancomycin?

A

binding at the D-ala-D-ala muramyl pentapeptide to sterically hinder the transglycosylation rxns (and indirectly prevent transpeptidation involved in elongation of peptidoglycan chains.

53
Q

What is the spectrum of microbial that vancomycin can treat?

A

MRSA, enterococci, Clostridium difficile (backup drug)

54
Q

How is there resistance to vancomycin? (explain the mechanism)

A

enterococcal resiste innobles change in the muramyl pentapeptid target such that terminal D-ala I replaced bh D-lactate

55
Q

Can vancomycin enter the CNS?

A

no

56
Q

How is vancomycin eliminated?

A

renal filtration

57
Q

S/E of use of vancomycin?

A

“red man syndrome” (histamine release)
ototoxicity (usually permanent, additive with other drugs
nephrotoxicity

58
Q

Which category of protein synthesis inhibition drugs act on the 30 S ribosome?

A

aminoglycosides, tetracyclines

59
Q

Which categories of protein synthesis inhibitions drugs act on the 50 S ribosomes?

A

Linezolid

Pristins dalfopristin/ quinupristin

chloramphenicol

macrolides and clindamycin

60
Q

Which drugs that inhibit protein synthesis of the cell wall inhibit formation of initiation complex?

A

aminoglycosides
linezolid

61
Q

Which drugs inhibit amino acid incorporation? (block attachment of aminoacyl tRNA to acceptor site (static) (protein synthesis inhibitors)

A

tetracyclines

Dalfopristin/ quinupristin

62
Q

Which drugs inhibit formation of peptide bond? (protein synthesis inhibitor drugs)

A

chloramphenicol

63
Q

Which drug inhibit translocation? (protein synthesis inhibitors)

A

macrolides and clindamycin

64
Q

Which protein synthesis inhibitors are the only ones which are bactericidal?

A

aminoglycosides

65
Q

MOA aminoglycosides and Linezolid.

A

interfere with initiation of codon functions-block association of 50S ribosomal subunit with mRNA -30S (static)

Misreading of code, incorporation of wrong amino acid (cidal) aminoglycosides only

66
Q

MOA tetracyclines and the pristine?

A

block the attachment of aminoacyl tRNA to acceptor site (static)

67
Q

What is the MOA of chloramphenicol?

A

inhibit the activity of peptidyltransferase (static)

68
Q

MOA macros and clindamycin?

A

inhibit translocation of peptide tRNA from acceptor to donorr site (static

69
Q

Which antimicrobials shouldn’t be used in pregnancy?

A

aminoglycosides, fluoroquinolone, sulfonamides, tetracyclines

70
Q

Which type of organisms are aminoglycosides useful in the treatment of? (What are some names of aminoglycoside agents)

A

gram-negative rods; gentamicin, tobramycin, amikacin

71
Q

Which aminoglycoside is the DOC for bubonic plague and tularemia?

A

stremtopmycin

72
Q

Side effects of aminoglycosides? Way to remember certain major characteristics of this drug class.

A

AmiNOglycosides

NO, NO, NO

Needs O2
Neg Organisms
Nephrotoxic and ototoxic

also neuromuscular blockade with dec release of ACh release

73
Q

Way to remember what Tetracyclines are the DOC for?

A

tets for Ticks

(rickettsia) RMSF, (Borrelia burgdoferi) Lyme disease, as well as chlamydial and mycoplasma species, H. pylori, brucella, vibirio, and treponema (back up drug)

74
Q

What are the names of tetracycline antibiotics?

A

doxycycline, minocycline, Tigecycline

75
Q

Use for Doxycycline? (specifically where can this drugs reach high levels in the body?)

A

prostates because reaches high levels in prostatic fluid

76
Q

Use for minocycline?

A

used in meningococcal carrier states

77
Q

What is the use for Tigecycline and why is the use good for this type of tetracycline?

A

used in complicated skin, soft tissue, and intestinal infections because can act on resistant gram pos. (MRSA, VREF, gram neg organisms, and anaerobes)

VREF - Vancomycin-resistant Enterococcus faecium

78
Q

How are most tetracyclines eliminated?

A

via the kidneys

79
Q

How is doxycycline eliminated?

A

liver

80
Q

Tetracylcines can bind what found in the body?

A

divalent cations Ca2+, Mg2+, Fe2+

81
Q

Which antimicrobials are known to be phototoxic?

A

tetracyclines

sulfonamides

quinolones

82
Q

Indications for chloramphenicol?

A

currently backup drug for infection due to salmonella typhi, B. fragilis, Rickettsia, and possibly bacterial meningitis

83
Q

Side effects of chloramphenicol

A

dose dependent bone marrow suppression common; aplastic anemia rare

“gray baby” syndrome in neonates (they have dec levels of glucuronosyltransferase)

84
Q

Indication for use of macrolides?

A

wide spectrum antibiotics

Gram- positive cocci (not MRSA)

Atypical organisms (chlamydia, mycoplasma, and ureaplasma species)

Legionella pneumophila

campylobacter jejunii

mycobacterium avium intracellular (MAC) Mac for Mac

H. pylori

85
Q

What are the most common organisms associated with community acquired pneumonia?

A

M. pneumonia, C. pneumonia, and viruses

Smokers: pneumococcus

M = mycoplasma
C= chlamydia

86
Q

Which drugs are commonly used in the treatment of community acquired pneumonia?

A

macrolides

87
Q

What is telithromycin used for?

A

a ketolide active against macrolide- resistant S. pneumonia

88
Q

S/E of using macrolides.

A

GI distress erythromycin, azithromycin > clarithromycin) due to stimulation of motion receptors

reversible deafness at high doses

increase QT interval

MACROS
Motility Issues GI
Arrythmias (QT prolongation)
Cholestatic hepatitis
Rash
eosinOphilia

89
Q

MOA clindamycin?

A

not a macrolide but same MOA and resistance

90
Q

What organisms can clindamycin be used to treat against?

A

narrow spectrum: gram positive cocci (including community-acquired MRSA) and anaerobes, including B. fragilis (back up drug)

91
Q

S/E clindamycin use?

A

pseudomembranous colitis (most likely cause)

92
Q

What is the MOA of Linezolid? (specifically)

A

inhibits initiation compl.ex in bacterial translation systems by preventing formation of N-formylmethionyl - tRNA- ribosome- mRNA ternary complex

93
Q

What is the spectrum of bacteria Linezolid can act against?

A

VRSA, VRE, and drug resistant pneumococci

94
Q

S/E Linezolid use?

A

bone marrow suppression (platelets), MAO-A and B inhibitor

95
Q

MOA Quinupristin-Dalfopristin.

A

Binding to sides one 50S ribosomal subunit they prentent integration of amino-acyl-tRNA with acceptor site and stimulate its dissociation from the ternary complex

96
Q

What is the spectrum of bugs quinupristin can act against?

A

vancomycin resistant staphylococci (VRSA) and other drugs resistant gram + cocci

97
Q

What are the streptogramins?

A

drugs ending in pristin

98
Q

Which enterococci can linezolid treat in comparison to streptogramins?

A

Streptogramins for E. faecium, including VRE faecium, but not for E. faecalis

Linezolid for both