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Microbiology 1 > Module 6: Antimicrobial Agents > Flashcards

Module 6: Antimicrobial Agents Flashcards

1
Q

Define antimicrobial agent

A

Chemotheraputic agent used for treatment of infectious diseases

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2
Q

What 4 criteria must an antibiotic have in order to be used?

A
  1. Selective toxicity (kill bacteria, no damage to host cells)
  2. Not cause allergic reaction
  3. Soluble in body fluids and capable of tissue penetration
  4. Microorganisms must not readily develop resistance
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3
Q

What are broad spectrum antibiotics?

A

Affect wide variety of bacteria, gram positive and negative

Must have action against some Enterobacteriaceae to be broad

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4
Q

What are narrow spectrum antibiotics?

A

Affects small group of bacteria

Gram positive OR negative, not both

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5
Q

Define bactericidal

A

Agent kills bacteria

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6
Q

Define bacteriostatic

A

Agent prevents bacteria from multiplying, then body defenses get rid of it

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7
Q

Why would a bacteriostatic agent not be used on immunocompromised patients?

A

There are no body defenses to get rid of the bacteria

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8
Q

What are the 5 possible modes of action an antibiotic may have?

A
  1. Inhibit cell wall synthesis
  2. Inhibit protein synthesis
  3. Inhibit DNA and RNA synthesis
  4. Inhibit cell membrane function
  5. Inhibit other metabolic processes
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9
Q

Why are agents which inhibit the cell wall synthesis of bacteria used? (2)

A
  1. Human cells don’t have a cell wall

2. Peptidoglycan in the bacteria cell wall is unique to bacteria

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10
Q

What is the core component of all cell wall synthesis inhibiting antibiotics? What is it made of?

A

Beta-lactam ring

Made of three carbons and one nitrogen molecules arranged in a ring

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11
Q

What do cell wall synthesis inhibiting antibiotics bind to?

A

Enzymes in the cell wall called Penicillin binding proteins

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12
Q

How do cell wall synthesis inhibiting antibiotics cause bacterial death?

A

The agents bind to cell wall enzymes that are the last stage of peptidoglycan synthesis, which inhibits cross-linking between the proteins
This causes weakness and eventual rupturing

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13
Q

Why are gram negative bacteria usually resistant to beta-lactam antibiotics?

A

They have a lipid layer covering the peptidoglycan layer, protecting it from the antibiotic

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14
Q

What are the 2 major beta-lactam antibiotic groups?

A

Penicillin and cephalosporins

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15
Q

What are the 4 groups of penicillin?

A

Natural, beta-lactamase resistant, extended spectrum, anti-pseudomonal

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16
Q

What are natural penicillins?

A

Penicillin where the original compound is extracted from Penicillium mold
The compound is Penicillin G or Benzylpenicillin

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17
Q

What spectrum does natural penicillin have?

A

Narrow, gram positive with a few gram negative

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18
Q

Is there bacterial resistance to natural penicillin? If so, how does it work?

A

Yes, it can be inactivated by bacteria which produces beta-lactamase (enzyme) which opens the beta-lactam ring

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19
Q

What is the clinical usage of natural penicillin?

A

Penicillin G - injection, resistant to stomach acid
Penicillin V - orally

Usually given with other drugs to improve absorption and retention

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20
Q

What laboratory testing is done in regards to bacterial sensitivity?

A 
Penicillin G used to test and applied to all other natural penicillins
EX: Penicillin G is sensitive, so are other penicillins (class concept)
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21
Q

What is class concept?

A

The test results for sensitivity to one antibiotics applies to all other antibiotics of the same class

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22
Q

How do beta-lactamase resistant penicillins work?

A

“Bulky” side chain added to protect the beta-lactam ring

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23
Q

What penicillins are included in the beta-lactamase resistant class?

A

Oxacillin, cloxacillin, dicloxacillin, methicillin

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24
Q

Is there bacteria resistance to beta-lactamase resistant penicillin? If so, how does it work?

A

Resistance occurs only when the bacteria develops it, by altering their penicillin binding proteins to prevent binding

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25
Q

What is the clinical use of beta-lactamase resistant penicillins?

A

Orally or injection, use determined by side chain which may alter absorption and excretion

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26
Q

What laboratory testing is done on beta-lactamase resistant penicillin in regards to sensitivity?

A

Class concept applies, oxacillin is usually used

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27
Q

What are extended spectrum penicillins?

A

Addition of NH2 (amine) groups to the side chain of penicillin allows antibiotic to penetrate the lipid layer of gram negative cells
Called aminopenicillins

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28
Q

What is the spectrum of aminopenicillins?

A

Broad, but not as effective against gram positive

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29
Q

What is the spectrum of beta-lactamase resistant penicillin?

A

Narrow gram positive, usually for Staphylococcus infections

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30
Q

Is there bacteria resistance to extended spectrum penicillin? If so, how does it work?

A

Susceptible to beta-lactamase

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31
Q

What laboratory testing is done on extended spectrum penicillin in regards to sensitivity?

A

Class concept applies, ampicillin is usually used

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32
Q

What are examples of extended spectrum penicillin?

A

Ampicillin, amoxicillin

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33
Q

What are anti-pseudomonal penicillins? Why are they used?

A

Two groups:
1. carboxy penicillins
2. Ureidopenicillins
Used because Pseudomonas and other Enterobacteriaceae produce beta-lactamase

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34
Q

What spectrum to anti-pseudomonal penicillins have?

A

Broad, less effective against gram positives

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35
Q

Is there resistance to anti-pseudomonal penicillin? If so, how does it work?

A

Can be inactivated by beta-lactamase from Staphylococcus

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36
Q

What is the clinical use for anti-pseudomonal penicillin?

A

Used against bacteria that is resistant to other antibiotics, very expensive
Usually used with aminoglycosides for Pseudomonas

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37
Q

What laboratory testing is done on anti-pseudomonal penicillin in regards to susceptibility?

A

Class concept does not apply, each antibiotic must be tested

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38
Q

What are examples of anti-pseudomonal penicillins? (2 groups)

A

Carboxypenicillin - carbenicillin, ticaricillin

Ureidopenicillin - azlocillin, mezlocillin, piperacillin

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39
Q

What are beta-lactamase inhibitors?

A

Compounds with weak antibiotic properties but that are able to render some beta-lactamase enzymes useless

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40
Q

What are 2 beta-lactamase inhibitors?

A

Clavulanic acid - amox-clav, ticar-clav

Sulbactam - with ampicillin

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41
Q

What are cephalosporins?

A

Beta-lactam antibiotics produced as fermentation products of fungus

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42
Q

How many cephalosporin generations exist?

A

4

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43
Q

How are cephalosporin generations separated?

A

By antibacterial spectrum

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44
Q

What are first generation cephalosporins?

A

Cephalothin, cefazolin, cephalexin

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45
Q

What is the spectrum of first generation cephalosporins?

A

Broad, most gram positives and moderate gram negatives

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46
Q

What is the clinical use of first generation cephalosporins?

A

Cephalothin and cefazolin injected, cephalexin oral

More expensive than penicillin

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47
Q

What laboratory testing is done on first generation cephalosporins in regards to sensitivity?

A

Class concept generally applies, Cepahlothin usually used

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48
Q

What are the second generation cephalosporins?

A

Cefaclor, cefonicid, cefotiam, cefotetan, cefamandole, ceforanide, cefuroxime, cefoxitin

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49
Q

What is the spectrum of second generation cephalosporins?

A

Broad, increased GNB activity but decreased GP activity

None effective against Pseudomonas

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50
Q

What sensitivity testing is done on second generation cephalosporins?

A

Class concept does not apply, each one must be tested

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51
Q

What are the third generation cephalosporins?

A

Cefixime, cefotaxime, ceftizoxime, cefoperazone, ceftazidime, ceftriaxone

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52
Q

What is the spectrum of third generation cephalosporins?

A

Broad, less against GP, more against Enterobacteriaceae and Pseudomonas

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53
Q

What sensitivity testing is done on third generation cephalosporins?

A

Class concept does not apply, each must be tested

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54
Q

What is one clinical use for third generation cephalosporins?

A

Crosses the blood-brain barrier more easily than first generations

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55
Q

What are the fourth generation cephalosporins?

A

Cefipime, cefpirome

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56
Q

What is the spectrum of fourth generation cephalosporins?

A

Broad

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57
Q

What is aztreonam?

A

Beta-lactam structure with no attachments that disrupts cell wall synthesis the same way penicillin and cephalosporin does

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58
Q

What is azteronam used for?

A

Very effective against Enterobacteriaceae and Pseudomonas that are resistant to other antibiotics, but not GP or anaerobes

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59
Q

What are ESBL’s?

A

Extended spectrum beta-lactamases

Enzymes that mediate resistance to extended spectrum cephalosporins (3rd gen)

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60
Q

What bacteria can produce ESBL’s?

A

Certain GNs like E. coli, K. pneumoniae and oxytoca

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61
Q

What happens if a bacteria is found out to be an ESBL?

A

All penicillin, cephalosporins, and aztreonam are reported as resistant

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62
Q

What is imipenem?

A

Beta-lactam antibiotic with unique side chain to make it resistant to most beta-lactamase
Part of Carbapenem class

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63
Q

What is the spectrum of inipenem?

A

Broad, widest spectrum of any current antibiotic, most GNBs and anaerobes
Superbugs are resistant (MRSA, VRE)

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64
Q

What is vancomycin?

A

Belongs to glycopeptide class, not a beta-lactam and does not bind to penicillin binding sites

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65
Q

How does vancomycin work?

A

Binds to precursors of cell wall synthesis

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66
Q

What is the spectrum of vancomycin?

A

Narrow gram positive, large molecule cannot penerate GN cell wall

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67
Q

What is the clinical use of vancomycin?

A

Usually reserved for MRSA, Clostridium difficile, and resistant Enterococcus

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68
Q

What are potential side effects of vancomycin?

A

Toxic, hearing loss

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69
Q

What is teicoplanin?

A

Newer complex glycopeptide with similar spectrum to vancomycin

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70
Q

What antibiotics have a cell wall synthesis inhibiting mode of action?

A

Penicillin, cephalosporins, aztreaonam, imipenem, vancomycin, teicoplanin

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71
Q

What is penicillins mode of action?

A

Cell wall synthesis inhibition

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72
Q

What is cephalosporins mode of action?

A

Cell wall synthesis inhibition

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73
Q

What is aztreaonams mode of action?

A

Cell wall synthesis inhibition

74
Q

What is imipenems mode of action?

A

Cell wall synthesis inhibition

75
Q

What is vancomycins mode of action?

A

Cell wall synthesis inhibition

76
Q

What is teicoplanins mode of action?

A

Cell wall synthesis inhibition

77
Q

All antibiotics whose mode of action is cell wall synthesis inhibition bactericidal or bacteriostatic?

A

Bactericidal

78
Q

What antimicrobials have a mode of action that inhibits protein synthesis?

A

Macrolides, chloramphenicol, tetracyclines, and aminoglycosides

79
Q

How to antimicrobials that inhibit protein synthesis work?

A

Differs between the groups

Most common site of action is where tRNA brings amino acids into place in ribosomes

80
Q

Why are protein synthesis inhibiting antimicrobials not overly toxic?

A

Human and bacterial ribosomes are slightly different

81
Q

What is erythromycin?

A

Belongs to Macrolide group, has large ring structure with about 20 carbon molecules and one or more “sugars” attached

82
Q

How does erythromycin work?

A

Binds to ribosomal subunits and halts addition of amino acids in polypeptide chain causing protein synthesis to stop
Bacteriostatic

83
Q

What is the spectrum of erythromycin

A

Narrow, mostly GP but some GN

Ineffective against Enterobacteriaceae

84
Q

What is the clinical use of erythromycin?

A

Common in S. pyogenes infection in people with pen allergies, some “exotics”: Mycoplasma, Legionella, Chlamydia
Absorbed well but too big to cross the blood-brain barrier
Orally, esther used to prevent vomitting and destruction

85
Q

What is clindamycin?

A

Lincosamide antibiotic similar to erythromycin

86
Q

What is the spectrum of clindamycin?

A

Similar to erythromycin (narrow, GP, some GN)

87
Q

What is the clinical use of clindamycin?

A

Similar to erythromycin but with better absorption and penetration
Good for anaerobes

88
Q

What are some side effects of clindamycin?

A

Diarrhea in 20% of users and many develop pseudomembranous colitis

89
Q

What is chloramphenicol?

A

Small molecule made of nitrobenzene ring and small side chain
First isolated from Streptomyces in soil

90
Q

How does chloamphenicol work?

A

Inhibits protein synthesis by binding to ribosomal subunits halting protein synthesis
Bacteriostatic

91
Q

What is the spectrum of chloramphenicol?

A

Broad, GP and Enterobacteriaceae

92
Q

What is the clinical use of chloramphenicol?

A

Penetrates most body tissue including the blood-brain barrier
Toxic, restricted to typhoid and meningitis when other antibiotics cannot penetrate the involved tissues

93
Q

What are the side effects of chloramphenicol in infants? What causes this?

A

Gray’s syndrome - ashen gray cyanosis, weak, listless
Chloramphenicol is conjugated in the liver before it is excreted and infant livers cannot convert it to an excretal form, and it builds up in their bodies
FATAL

94
Q

What are the side effects in adult patients taking chloramphenicol?

A

May develop fatal irreversible bone marrow aplasia (aplastic anemia)
May cause dose-related bone marrow depression that will go away after discontinuation

95
Q

What is tetracycline?

A

Has four fused rings and additions of different side chains, yellow colored

96
Q

What are examples of tetracyclines?

A

Terramycin, aureomycin, doxycycline, minocycline

97
Q

How do tetracyclines work?

A

Bind to ribosomal subunit preventing binding of tRNA and mRNA which inhibits protein synthesis
Bacteriostatic

98
Q

What spectrum do tetracyclines have? Is there any resistance?

A

Broad, some Enterobacteriaceae

Resistance is common

99
Q

What is the clinical use of tetracyclines?

A

“Exotics”: chlamydia, mycoplasma, rickettsial infections

Orally

100
Q

What are some side effects of tetracyclines?

A

Yellow teeth from tetracycline deposits
Prevents magnesium and calcium absorption, not for child use
May interfere with birth control

101
Q

What are aminoglycosides?

A

Large group of antibiotics sharing same structure of amino sugars liked by glycosidic bonds

102
Q

How do aminoglycosides work?

A

Inhibit protein synthesis by binding to ribosomal subunit resulting in protein synthesis interruption at several steps
Bactericidal

103
Q

What is the clinical use of aminoglycosides?

A

No good for anaerobes (cannot penetrate in reduced oxygen)
Too big to penetrate CNS
Often given with beta-lactams, as uptake is facilitated by cell wall inhibitors
Also affected by presence of calcium and magnesium

104
Q

What is required for aminoglycoside susceptibility testing?

A

Media that has the same calcium and magnesium concentration as the body
Class concept does not apply, all must be tested

105
Q

What is the spectrum of aminoglycosides?

A

Broad including Enterobacteriaceae and Pseudomonas

106
Q

What are side effects of aminoglycosides?

A

Toxicity - kidney

Can damage the eighth cranial nerve and cause hearing loss

107
Q

What are some examples of aminoglycosides?

A

Kanamycin - for Enterobacteriaceae
Gentamicin - for Pseudomonas, in combination with carbenicillin or ticaricillin, resistant Enterobacteriaceae or S. aureus
Tobramycin - for Pseudomonas with anti-pseudomonal penicillin
Amikacin and netilmicin
Spectinomycin - for pen resistant N gonorrhoeae

108
Q

What are fluoroquinolones?

A

Belong to quinolone class, two ringed structure with different side chains and substitutions including fluorine

109
Q

What are examples of fluoroquinolones?

A

Ciprofloxacin and norfloxacin

110
Q

What is the mode of action of fluoroquinolones?

A

Inhibit DNA and RNA synthesis
Interfere with DNA gyranase enzymes preventing DNA replication
Bactericidal

111
Q

What is the spectrum of fluoroquinolones?

A

Broad, GP and wide range of GN including Enterobacteriaceae and Pseudomonas

112
Q

What are the side effects of fluoroquinolones?

A

Toxic, irreversible cartilage and skeletal damage

Not for under 18 year olds or pregnant/nursing mothers

113
Q

What is nalidixic acid?

A

Belongs to quinolone group

114
Q

What is the spectrum of nalidixic acid?

A

Broad, GN and Enterococci

115
Q

What is the clinical use of nalidixic acid?

A

Urinary tract infections, concentrates there

Not effective elsewhere

116
Q

What is the mode of action of metronidazole (flagyl)?

A

Breaks DNA strands

Bactericidal

117
Q

What is the clinical use of metronidazole (flagyl)?

A

Anaerobic infections, protazoan parasitic infections like Trichomonas and Giardia

118
Q

What antimicrobials have the mode of actions of inhibiting DNA and RNA synthesis?

A

Quinolones, fluoroquinolones, nalidixic acid, metronidazole (flagyl)

119
Q

What antimicrobials have the mode of action of inhibiting cell membrane function?

A

Polymyxins

120
Q

What are polymyxins?

A

Belong to antibiotic group Polypeptides

121
Q

What is the mode of action of polymyxins?

A

Inhibit cell membrane function by attaching to the membrane and causing leakage and death
Bactericidal

122
Q

What is the spectrum of polymyxins?

A

Narrow, GN

123
Q

What are examples of polymyxins?

A

Polymyxin B, Polymyxin E (Colistin)

124
Q

What is the clinical use of polymyxins?

A

Used to be used for Pseudomonas before more effective and less toxic antibiotics were found

125
Q

What are the side effects of polymyxins?

A

Toxic

Nephrotoxicity (kidney) and neurotoxicity (nerves)

126
Q

What agar plate and disc is a polymyxin used in? What does it do?

A

Colistin is used in the CNA plate to inhibit gram negative growth
Colistin disc also used to determine gram reaction

127
Q

What antimicrobials have the mode of action of inhibiting other metabolic processes?

A

Sulfonamides, trimethoprim, nitrofurantoin

128
Q

What is a sulfonamide?

A

Antimicrobial but not an antibiotic (synthetic)
Derivative of small compound called para-aminobenzene sulfonamide, similar structure to DNA precursor para-amino benzoic acid

129
Q

How do sulfonamides work?

A

Inhibits other metabolic processes by preventing synthesis of folic acid (DNA precursor)
Sulfonamide competes for binding enzyme with PABA (similar structure)
Competitive inhibition
Bacteriostatic

130
Q

What is the spectrum of sulfonamides?

A

Broad, but many bacteria develop resistance

131
Q

What is the clinical use of sulfonamides?

A

Some enter the CNS, popular for UTIs

Most effective with trimethoprim = SXT (cortrimoxazole/trimethoprim sulfamethoxazole)

132
Q

What is trimethoprim?

A

Similar to sulfonamides

133
Q

How does trimethoprim work?

A

Inhibits other metabolic processes by interfering with folic acid production from PABA by competitive inhibition with another enzyme

134
Q

What is the spectrum of trimethoprim?

135
Q

What is the clinical use of trimethoprim?

A

Often used with sulonamide sulfamethoxazole to make cortrimoxazole/SXT
Used for UTIs

136
Q

What is nitrofurantoin?

A

Belongs to synthetic group called nitrofurans

137
Q

What is the mode of action of nitrofurantoin?

A

Inhibits other metabolic processes by damaging DNA or interfering with enzyme involved in protein translation
Not really understood
Bactericidal in high concentration, bacteriostatic in low concentration

138
Q

What is the spectrum of nitrofurantoin?

139
Q

What is the clinical use of nitrofurantoin?

A

Low blood levels, ineffective for most infections

Concentrated in the urinary system, used for UTIs

140
Q

The following characteristic defines an antimicrobial agent as an antibiotic

a. bacteria do not readily develop resistance to it
b. all or part of the compound originally produced by a microorganism
c. it selectively kills microorganisms without harming host cells
d. it is effective against bacteria in low concentrations

A

b. all of part of the compound originally produced by a microorganism

141
Q

All of the following are criteria making an antibiotic useful clinically except

a. unable to penetrate membranes of prokaryotic cells
b. soluble in body fluids
c. not cause allergic reactions
d. bacteria should not readily develop resistance

A

a. unable to penetrate membranes of prokaryotic cells

142
Q

Which of the following is not a target area of antimicrobial agents

a. cell wall
b. plasmids
c. cell membrane
d. protein synthesis

A

b. plasmids

143
Q

The beta-lactamase resistant penicillin usually used for susceptibility testing is

a. ampicillin
b. oxacillin
c. benzylpenicillin
d. ticaricillin

A

b. oxacillin

144
Q

The following penicillin should be included in the antimicrobial susceptibility test for E. coli (gram negative rod)

a. oxacillin
b. methicillin
c. penicillin G
d. ampicillin

A

d. ampicillin

145
Q

Anti-pseudomonal penicillin are often given with the following type of antibiotic because of synergistic action

a. sulfonamides
b. trimethoprim
c. aminoglycosides
d. macrolides

A

c. aminoglycosides

146
Q

Clavulanic acid and sulbactam are

a. beta-lactamase inhibitors
b. beta-lactamase antibiotics
c. anti-pseudomonal penicillins
d. cephalosporins

A

a. beta-lactamase inhibitors

147
Q

The generation of cephalosporins showing the most activity against gram negative bacteria is

a. first
b. second
c. third

148
Q

The class concept can be used in susceptibility testing of the following

a. first generation cephalosporins
b. second generation cephalosporins
c. third generation cephalosporins
d. all of the above

A

a. first generation cephalosporins

149
Q

Imipenem is an antibiotic that is effective against

a. MRSA
b. VRE
c. most gram negative rods and anaerobes
d. all of the above

A

c. most gram negative rods and anaerobes

150
Q

The antibiotic associated with aplastic anemia is

a. chloramphenicol
b. tetracycline
c. ciprofloxacin
d. nalidixic acid

A

a. chloramphenicol

151
Q

Tetracycline is not recommended for children because

a. toxic levels accumulate because of an immature liver
b. it commonly causes pseudomemranous colitis
c. bone structure may be altered
d. of nephrotoxicity

A

c. bone structure may be altered

152
Q

Calcium and magnesium ion concentrations should be adjusted in susceptibility test media to correspond to the of body tissues for testing

a. tobramycin
b. chloramphenicol
c. carbenicillin
d. norfloxacin

A

a. tobramycin

153
Q

The following antibiotic is a fluoroquinolone

a. kanamycin
b. carbenicillin
c. ciprofloxacin
d. nirtofurantoin

A

c. ciprofloxacin

154
Q

A limitation on the use of fluoroquinolones is

a. severe allergic reactions
b. aplastic anemia
c. pseudomembranous colitis
d. skeletal damage in young people

A

d. skeletal damage in young people

155
Q

The target site for antimicrobial action of fluoroquinolones is

a. cell wall
b. DNA synthesis
c. protein synthesis
d. cell membrane

A

b. DNA synthesis

156
Q

An antibiotic that is used for treating anaerobic infections and some protozoans is

a. griseofulvin
b. metronidazole
c. nalidixic acid
d. trimethoprim

A

b. metronidazole

157
Q

Co-trimoxazole is a combination of

a. carbenicillin and gentamicin
b. sulfonamide and trimethoprim
c. tetracycline and gentamicin
d. sulfonamide and colistin

A

b. sulfonamide and trimethoprim

158
Q

An antibiotic with a gram negative spectrum that is used in media as a selective agent is

a. vancomycin
b. trimethoprim
c. erythromycin
d. colistin

A

d. colistin

159
Q

An antibiotic that interferes with cell membrane function is

a. trimethoprim
b. metronidazole
c. polymyxin
d. erythromycin

A

c. polymyxin

160
Q

Mycoplasma is bacteria that lack a cell wall. Which of the following antimicrobials would be expected to be effective in treating mycoplasma pneuonia?

a. amoxicillin
b. erythromycin
c. vancomycin
d. cephalosporin

A

b. erythromycin

161
Q

This question may have more than 1 correct answer:
The following antimicrobial agents are classed as beta-lactams:

a. gentimicin
b. cephalosporin
c. chloramphenicol
d. penicillins

A

b and d

Cephalosporin and penicillin

162
Q

This question may have more than 1 correct answer:
The bacterial cell wall is a suitable target site for antimicrobials because

a. antibiotics bind to teichoic acids
b. it contains unique polysaccharides
c. it contains a unique pohspolipid bilayer
d. peptidoglycan of bacterial cell walls is not found in human cells

A

d. peptidoglycan of bacterial cell wall is not found in human cells

163
Q

This question may have more than 1 correct answer:
Anti-pseudomonal penicillins include:

a. amikacin
b. ureidopenicillins
c. tobramycin
d. carbenicillin

A

b and d

Ureidopenicillins and carbenicillin

164
Q

This question may have more than 1 correct answer:
Vancomycin:

a. inhibits cell wall synthesis
b. is a beta-lactam antibiotic
c. has a gram positive spectrum
d. is bacteriostatic

A

a and c

Inhibits cell wall synthesis and has a gram positive spectrum

165
Q

This question may have more than 1 correct answer:
The following antibiotics inhibit bacterial growth by interfering with protein synthesis:

a. macrolides
b. tetracycline
c. aminoglycosides
d. erythromycin

A

a, b, c, and d

Macrolides, tetracycline, aminoglycosides, and erythromycin

166
Q

This question may have more than 1 correct answer:
Erythromycin:

a. is effective against Enterobacteriaceae
b. is a macrolide
c. interferes with folic acid production
d. has a gram positive spectrum

A

b and d

Is a macrolide and has a gram positive spectrum

167
Q

This question may have more than 1 correct answer:
The following antibiotics are aminoglycosides:

a. tobramycin
b. kanamycin
c. gentamicin
d. aureomycin

A

a, b, and c

Tobramycin, kanamycin, and gentamicin

168
Q

This question may have more than 1 correct answer:
The following statements apply to aminoglycosides

a. effective against gram negative rods
b. broad spectrum
c. inhibit protein synthesis
d. class concept applies for susceptibility testing

A

a, b, and c

Effective against gram negative rods, broad spectrum, and inhibits protein synthesis

169
Q

This question may have more than 1 correct answer:
The following antimicrobials are reserved for treating urinary tract infections

a. nalidixic acid
b. sulfonamides
c. nitrofurantoin
d. trimethoprim

A

a, b, c, and d

Nalidixic acid, sulfonamides, nitrofurantoin, and trimethoprim

170
Q

This question may have more than 1 correct answer:
Sulfonamides and trimethoprim have the following in common:

a. mode of action is competitive inhibition
b. broad spectrum
c. interfere with production of folic acid from PABA
d. interfere with nucleic acid synthesis in humans

A

a, b, and c

Mode of action is competitive inhibition, broad spectrum, and interfere with production of folic acid from PABA

171
Q

The 4 possible answers are: bactericidal, bacteriostatic, broad spectrum, and narrow spectrum

An antibiotic such as penicillin that causes major rupture of predominately gram positive cell walls is:

A

bactericidal and narrow spectrum

172
Q

The 4 possible answers are: bactericidal, bacteriostatic, broad spectrum, and narrow spectrum

A polymyxin that attaches to the cell membrane of gram negative bacteria and causes leakage of contents is:

A

bactericidal and narrow spectrum

173
Q

The 4 possible answers are: bactericidal, bacteriostatic, broad spectrum, and narrow spectrum

A sulfonamide that inhibits formation of folic acid and stops growth of gram positive and negative bacteria is:

A

bacteriostatic and broad spectrum

174
Q

The 5 possible answers are: Penicillin G, Oxacillin, Methicillin, Ampicillin, and Carbenicillin

Beta-lactam antibiotics are:

A

All of them

Penicillin G, Oxacillin, Methicillin, Ampicillin, and Carbenicillin

175
Q

The 5 possible answers are: Penicillin G, Oxacillin, Methicillin, Ampicillin, and Carbenicillin

Natural penicillins are:

A

Penicillin G

176
Q

The 5 possible answers are: Penicillin G, Oxacillin, Methicillin, Ampicillin, and Carbenicillin

Broad spectrum penicillins are:

A

Ampicillin and Carbenicillin

177
Q

The 5 possible answers are: Penicillin G, Oxacillin, Methicillin, Ampicillin, and Carbenicillin

The penicillins used for treatment of Pseudomonas are:

A

Carbenicillin

178
Q

The 5 possible answers are: Penicillin G, Oxacillin, Methicillin, Ampicillin, and Carbenicillin

Benzylpenicillins are:

A

Penicillin G

179
Q

The 5 possible answers are: Penicillin G, Oxacillin, Methicillin, Ampicillin, and Carbenicillin

Penicillins that are activated by the action of beta-lactamase are:

A

Penicillin G, Ampicillin, and Carbenicillin

180
Q

The 5 possible answers are: Penicillin G, Oxacillin, Methicillin, Ampicillin, and Carbenicillin

Class concept applies for susceptibility testing for:

A

Penicillin G, Oxacillin, Methicillin, and Ampicillin

181
Q

The 5 possible answers are: Penicillin G, Oxacillin, Methicillin, Ampicillin, and Carbenicillin

Carboxypenicillins are:

A

Carbenicillin

Microbiology 1 (11 decks)

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