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Micro 425 > Exam 3 (Antibiotics) > Flashcards

Exam 3 (Antibiotics) Flashcards

1
Q

Chemical substance produced by a microorganism that inhibits multiplication and growth or kills other microorganisms:

A

Antibiotic

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2
Q

Chemical substance that is derived from a microorganism or that is produced synthetically that inhibits multiplication and growth or kills microorganisms:

A

Antimicrobial

antibacterial/antiparasitic/antifungal/antiviral

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3
Q

T/F

All antibiotics are antimicrobials, but not all antimicrobials are antibiotics:

A

True.

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4
Q

Natural antibiotics tend to be ___toxic and ____ effective than synthetic:

A

more toxic

less effective

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5
Q

Result with 2 drugs is significantly less than when used individually:

A

Antagonistic

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6
Q

Do the Vitek2 and E-test provide the MIC:

A

yes

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7
Q

MIC determines the ______ effect:

A

bacteriostatic

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8
Q

MBC determines the ____ effect:

A

bactericidal

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9
Q

____ is found after the MIC using a series of steps/dilutions:

A

MBC

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10
Q

Broad spectrum antibiotics are effective against both :

A

Gram+/-

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11
Q

What are the two factors contributing to MRSA:

A

mecA gene

Beta lactamase

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12
Q

How does the mecA gene contribute to MRSA:

A

mecA —> PBP—> PBP2a
(pbp= peptide binding protein)
(pbp2a= analog binding)

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13
Q

List the 3 classes of cell wall synthesis inhibitors:

BGF

A

Beta-lactams
Glycopeptides
Fosfomycins

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14
Q

List the 4 groups of beta-lactams:

PCCM

A

Penicilllin
Cephalosporin
Carbapenems
Monobactams

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15
Q

The beta-lactam ring is formed by the binding of which two amino acids:

A

Cysteine and Valine

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16
Q

T/F

Beta-lactams are toxic to humans:

A

False.

Humans cells lack the murein layer, so are unaffected

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17
Q

Beta-lactamase renders beta-lactams ineffective by:

A

opening beta-lactam ring, inhibiting the drug from binding to PBP’s

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18
Q

ESBL stands for:

A

Extended spectrum beta-lactamases

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19
Q

______ are derived from beta-lactamase and confer the bacteria resistance to penicillins and cephalosporins:

A

ESBL’s

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20
Q

Glycopeptides are only used for Gram___:

A

Gram+

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21
Q

Why are glycopeptides ineffective against GNB:

A

They are too large to penetrate outer cell membrane

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22
Q

This cell wall synthesis inhibitor is similar in structure to Penicillins:

A

Cephalosporins

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23
Q

This cell wall synthesis inhibitor binds to precursors of cell well synthesis:

A

Glycopeptides

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24
Q

Will beta-lactamase affect glycopeptides:

A

No

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25
Q

How do cell membrane function inhibitors work:

A

Disrupt cell membrane causing leakage of ions/macromolecules necessary for cell life

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26
Q

List two examples of Cell membrane function inhibitors:

A

Polymyxin B

Colistin

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27
Q

_____ act as detergents opening up the cell membrane of primarily Gram- bacteria:

A

Polymyxin-B

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28
Q

Inhibitors of protein synthesis interfere with protein synthesis in 3 ways:

A
  • interrupt initial formation of proteins
  • interfere w/ accurate reading of mRNA
  • disrupt ribosomal-mRNA complex
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29
Q

List some drug classes that work by inhibiting protein synthesis:

A 
Aminoglycosides
Macrolides
Ketolides
Tetracyclines
Phenicols
Glycyclines
Oxazolidinones
Ansamycins
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30
Q

Are aminoglycosides bacteriostatic or bactericidal:

A

Bactericidal

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31
Q

This group of protein synthesis inhibitors are monitored via peak and trough values:

A

Aminoglycosides

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32
Q

Gentamicin belongs to this group:

A

Aminoglycoside

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33
Q

Macrolides are bacteriostatic by this mechanism:

A

Inhibit protein synthesis

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34
Q

Erythromycin and Clindamycin belong to this group:

A

Macrolides

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35
Q

Macrolides are effective against Gram___::

A

Gram+

macrolides are too large to penetrate the outer membrane of gram- bacteria

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36
Q

This protein synthesis inhibitor is only used in serious Gram- infections, and is monitored carefully for bone marrow aplasia:

A

Chloramphenicol

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37
Q

Are aminoglycosides effective against anaerobes:

A

no

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38
Q

Why are tetracyclines contraindicated for use in children under age 8:

A

Discoloration of teeth

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39
Q

List the 3 groups that inhibit DNA/RNA synthesis:

FMR

A

Fluoroquinolones
Metronidazole
Rifampin

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40
Q

This DNA/RNA synthesis inhibitor is made from derivatives of naladixic acid and is broad spectrum:

A

Fluoroquinolones

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41
Q

List the 3 groups that inhibit metabolic processes:

SNT

A

Sulfonamides
Nitrofurantoin
Trimethoprim

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42
Q

This is a metabolic process inhibitor that is used for urinary tract only:

A

Nitrofurantoin

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43
Q

This group works by competitive inhibition of folic acid synthesis:

A

Sulfonamides

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44
Q

Trimethoprim is frequently combined with _____:

A

Sulfonamides

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45
Q

T/F

Resistance to Rifampin develops quickly and is usually used in combination with others:

A

True

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46
Q

Are sulfonamides broad spectrum?

A

Yes

except Pseudomonas is resistant

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47
Q

Kirby Bauer disk diffusion testing utilizes what type of agar:

A

Mueller-Hinton

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48
Q

Why is constant agar depth important with Kirby Bauer testing, what results from too deep, too thin?

A

Too deep= smaller zones, false R

Too thin= larger zones, false S

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49
Q

Why is it important to use McFarland Standard, what results from being too light, too heavy?

A

Too light= false S

Too heavy= false R

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50
Q

For Kirby Bauer disk diffusion, disks must be applied within ___ minutes of streakin plate:

A

15 minutes

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51
Q

Incubate plates at ____C for Kirby Bauer disk diffusion:

A

35 C

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52
Q

Does Kirby Bauer testing provide MIC:

A

no.

e test and vitek do

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53
Q

How do you report results of Kirby Bauer disk testing:

A

Sensitive
Intermediate
Resistant

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54
Q

T/F
In clinical setting, the interpretive results of the Kirby bauer test (S/I/R) provide necessary amount of information for clincians to treat patients MOST of the time:

A

True

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55
Q

This is a gradient diffusion method using plastic strips containing varying concentrations of an antimicrobial, does provide MIC:

A

E-test

56
Q

Another name for the Serum bacteriocidal test (SBT):

A

Schlichter test

57
Q

This test is used to measure ATB activity in the patient’s serum, and determines if treatment is effective:

A

Schlichter test

58
Q

T/F

Two serum specimens are required for Schlichter test, and it provides both MIC and MBC:

A

True

59
Q

_____ resistance is when changes in cell structure or physiology resulting in less susceptibility than previously observed:

A

Biologic

60
Q

This type of resistance results from physical/chemical characteristics of the environment:

A

Environmentally mediated resistance

61
Q

What are some contributing factors of environmentally mediated resistance:

A

pH changes
anaerobic atmosphere
Cation concentration (Mg and Ca)
Thymine/Thymidine content

62
Q

How does a decrease in pH affect erythromycin and aminoglycoside activity:

A

Decreases activity

63
Q

pH increase_______ tetracycline activity:

A

decreases

64
Q

Anaerobic conditions decreases _______ activity:

A

aminoglycoside

65
Q

If cations outcompete the antibiotic for the negatively charged sites, _____ antibiotic will be taken up:

A

Less

66
Q

Thymidine interferes with antibiotics targeting _____ synthesis such as ______:

A

folic acid

sulfonamides

67
Q

List the 4 types of resistance:

BCEM

A

Biologic
Clinical
Environmentally mediated
Microbial mediated

68
Q

This type of resistance is defined as intrinsic/natural/consistently inherited resistance resulting from normal genetic, structural, physiologic state of the organism:

A

Microbial mediated resistance

69
Q

What are the two types of microbial mediated resistance:

A

Natural/inherited

Acquired

70
Q

Defined as a resistance to certain antibiotics expressed by a subset of a microbial population that is generally considered to be susceptible to these antibiotics according to traditional in-vitro susceptibility testing:

A

Heteroresistance

71
Q

List two examples of heteroresistance:

A

VISA

VRSA

72
Q

If an ESBL is detected, all penicillins, cephalosporins, and aztreonam should be reported as ______:

A

Resistant

73
Q

VISA/VRSA are susceptible to:

A

daptomycin
rifampin
tetracycline

74
Q

These resistant organisms are treated with streptogramins and oxazolidinones:

A

VRE’s

75
Q

These are enzymes that mediate resistance to extended spectrum cephalosporins and monobactams, but do not affect cephamycins:

A

ESBL’s

76
Q

_____ are typically effective for treating ESBL’s and have been considered a first line of defense:

A

Carbapenums

77
Q

CRE stands for:

A

Carbapenum resistant Enterococci

they have carbapenumases

78
Q

ESBL’s are produced by Gram- rods of ________:

A

Enterobacteriaceae

79
Q

VRSA emerged from the exchange of genetic material from _____ to _____:

A

VRE

MRSA

80
Q

This test is for macrolide inducible resistance to clindamycin:

A

D-test

81
Q

A positive D test appears as:

A

A ‘D’ shape surrounding the clindamycin disk

82
Q

A positive D test indicates:

A

the presence of macrolide inducible resistance to clindamycin produced by an inducible methylase that alters the common ribosomal binding site for macrolides, clindamycin, and the group B Streptogramins.

83
Q

Biologic antimicrobials are most often derived from this source:

A

fungals

84
Q

Result with 2 drugs is greater than the response of each drug separately:

A

synergystic

85
Q

Glycopeptides and bacitracin are only effective against _______:

A

Gram+ bacteria

86
Q

Polymyxins are usually only effective against ______:

A

Gram- bacteria

87
Q

________ and ______ are only effective against aerobic organisms, while ______ are generally only effective for anaerobes:

A

Aminoglycosides/Sulfonamides

Nitroimidazoles

88
Q

The structure of ____ vary by sides chains off basic structure:

A

aminoglycosides

89
Q

T/F

Beta-lactams can target both Gram+/- bacteria:

A

True, but varies depending on specific antibiotic

90
Q

Are beta-lactams bacteriostatic or bactericidal:

A

Bactericidal

91
Q

Beta lactam ring binds to _____, inhibiting its’ action

A

PBP

92
Q

Is beta-lactamase produced by Gram+ or Gram-:

A

Both

93
Q

ESBL’s are derived from _____, and confer the bacterial resistance to ____ and ____:

A

beta-lactamase

penicillins and cephalosporins

94
Q

Polymyxins have both ____ and ____ effects:

A

bactericidal

Bacteriostatic

95
Q

These may be used as a last resort when bacteria such as Pseudomonas aeruginosa are resistant to other empirical treatments:

A

Polymyxin B and Colistin

inhibitors of cell membrane function

96
Q

List the inhibitors of cell membrane function, and if they are more active against Gram + or -:

A

Polymyxin B
Colistin

Gram-

97
Q

are glycopeptides beta-lactams:

A

no

98
Q

Glycopeptides are only used for Gram____:

A

Gram+

99
Q

Why don’t glycopeptides work on Gram-:

A

too larger to penetrate outer cell membrane

100
Q

Vancomycin is what kind of drug:

A

Glycopeptide

101
Q

Vancomycin works on Gram___:

A

Gram+

is a glycopeptide

102
Q

These drugs bind to precursors of cell wall synthesis:

A

Glycopeptides

103
Q

These are structurally similar to beta-lactams:

A

cephalosporins

104
Q

This group of antibiotics has limited tissue distribution and requires elimination via the kidneys:

A

aminoglycosides

105
Q

Gentamicin, Tobramycin, Amikacin are examples of :

A

aminoglycosides

106
Q

Aminoglycosides are active against Gram___:

A

Gram+/-

107
Q

Are aminoglycodes effective against anaerobes?

A

no

108
Q

Aminoglycosides are often used in combination with ______ or ______ for more rapid killing:

A

beta-lactams

glycopeptides

109
Q

Macrolides are bacteriostatic or bactericidal?

A

bacteriostatic

110
Q

T/F

Erythromycin and Clindamycin work by protein synthesis inhibition:

A

True

111
Q

This protein synthesis inhibitor is broad spectrum, bacteriostatic, effective against Gram+/- and intracellular bacterial pathogens such as chlamydia and rickettsia:

A

Tetracycline

112
Q

Are fluoroquinolones broad or narrow spectrum:

A

broad

113
Q

This inhibitor of DNA/RNA synthesis is active against Gram- anaerobes:

A

Metronidazole

114
Q

List the 3 drugs that interfere with enzymes necessary for DNA replication/transcription:

A

Fluoroquinolones
Metronidazole
Rifampin

115
Q

Why is the folic acid pathway important in microbes:

A

because it produces precursors for DNA synthesis

116
Q

Which inhibitor of folic acid synthesis works via competitive inhibition of folic acid synthesis:

A

Sulfonamides

117
Q

Sulfonamides are broad spectrum, but ____is resistant to them:

A

Pseudomonas

118
Q

These are often combined with sulfonamides:

A

Trimethoprin

119
Q

List some of the side effects of metabolic process inhibitors:
(FMR)

A

nausea
nephrotoxicitiy
bone marrow toxicity
allergic rxns

120
Q

_________ monitors the evolution of resistance and helps drive new drug research:

A

Susceptibility testing

121
Q

T/F
Mueller-Hinton agar is used for Kirby Bauer testing because of it’s well defined chemical composition, constant and reproducible, buffered to prevent pH change, and it is not antagonistic toward antibiotic activity:

A

True

122
Q

In Kirby Bauer testing, plates are incubated at this temp, and checked after ___ hours:

A

35 C

16-18 hours

123
Q

This may be used to determine MIC when you have fastidious or slow growing organisms that do not perform well using automated methods:

A

E-test

124
Q

This test measures antibiotic activity in the patient’s serum:

A

Schlichter test (SBT)

125
Q

In the Schlichter test, the trough specimen is collected ____ before the next dose, and the peak specimen is collected ____ after dose when concentration is highest, dilutions of each specimen are set up and inoculated with bacterial isolate from patient and incubated overnight:

A

Tough: 15 min before next dose
Peak: 30-60 mins after dose

126
Q

T/F

The Schlichter test provides both the MIC and MBC:

A

True

127
Q

Tetracycline works best as pH ____:

A

decreases

128
Q

Aminoglycosides work best as pH ____:

A

increases

129
Q

Aminoglycosides have net____ charge, Pseudomonas has a net ___ charge, and are affected by Cations:

A

net + charge

net - charge

130
Q

Intrinsic/natural/consistently inherited resistance, results from normal genetic, structural, physiologic state of the organism:

A

microbial mediated resistance

131
Q

Gram- are resistant to macrolides due to ____:

A

size

132
Q

What are two examples of heteroresistance:

A

VISA

VRSA

133
Q

Does Pseudomonas aeruginosa produce ESBL’s?

A

yes

134
Q

ESBL’s provide resistance to several beta lactam antibiotics, including ___, ___, and ____:

A

penicillins
cephalosporins
monobactams

135
Q

Klebsiella pneumoniae and E. coli both have ____strains:

A

CRE

carpapenem resistant enterobacteriaceae

Micro 425 (12 decks)

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