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Fall 2024 > Microbiology CH 10 - Antimicrobial Treatments > Flashcards

Microbiology CH 10 - Antimicrobial Treatments Flashcards

1
Q

What is a compound that can be used to kill or prevent the growth of one or more microorganisms called?

A

Antimicrobial

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2
Q

Antimicrobial includes what 4 compounds?

A
  1. Antibiotics
  2. Antifungals
  3. Antihelminthics
  4. Antiprotozoans
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3
Q

What do antibiotics target?

A

Bacteria

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4
Q

What do antifungals target?

A

Fungi

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5
Q

What do anthelminthics target?

A

Worms

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6
Q

What do antiprotozoans target?

A

Parasitic protists

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7
Q

What is the goal of antimicrobial chemotherapy?

A

To administer a drug that will target the infectious organism without harming the host

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8
Q

What are the 9 parts to the nonexistent ‘ideal’ microbial?

A
  1. Toxic to the microbe but nontoxic to host cells
  2. Relatively soluble; functions even when highly diluted in body fluids
  3. Remains potent long enough to act and is not broken down or excreted prematurely
  4. Does not lead to the development of antimicrobial resistance
  5. Complements or assists the activities of the host’s defenses
  6. Remains active in tissues and body fluids
  7. Readily delivered to the site of infection
  8. Reasonably priced
  9. Does not disrupt the host’s health by causing allergies or predisposing the host to other infections
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9
Q

Can antimicrobial compounds be found throughout nature?

A

Yes

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10
Q

Name 2 BACTERIA species that can produce antimicrobial compounds

A
  1. Streptomyces
  2. Bacillus
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11
Q

Name an animal that can produce antimicrobial compounds

A

Frogs

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11
Q

Name 2 FUNGI species that can produce antimicrobial compounds

A
  1. Penicillin
  2. Cephalosporin
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12
Q

What are made in labs to mimic natural antimicrobials?

A

Synthetic Drugs

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13
Q

What is made by chemically modifying naturally-occurring compounds?

A

Semisynthetic Drugs

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14
Q

What 3 things must be known before using antimicrobials?

A
  1. Identity of organism
  2. Organism’s susceptibility to various drugs
  3. Condition of the infected individual
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15
Q

What are the 3 ways to identify microbes?

A
  1. DNA Sequencing
  2. Staining, morphology, and physiology
  3. Advanced identification technologies such as Mass-Spectrometry
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16
Q

What are the 3 steps to the Kirby Bauer Technique?

A
  1. Bacteria is inoculated on general media, then premeasured antibiotics are placed on media
  2. Measure zone of inhibition
  3. Compare each antimicrobial’s zone of inhibition to a table of standards
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17
Q

What is the table of standards used for SPECIFICALLY within the Kirby Bauer Technique?

A

Identify which antimicrobials an organisms is Resistant (R) or Sensitive (S) to

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18
Q

What is the zone of inhibition?

A

Space around disc where the organism did not grow

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19
Q

What can you determine by adding various amounts of an antimicrobial to different broth cultures?

A

Minimum Inhibitory Concentration (MIC) for a particular organism-antimicrobial pairing

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20
Q

Why may there be a different between antimicrobial sensitivity in-vitro (in test tube) and in-vivo(in a living host)?

A

Different compounds may get metabolized differently by the body

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21
Q

What is the ratio of how toxic to humans an antimicrobial is compared to the minimum effective dose?

A

Therapeutic Index (TI)

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22
Q

What does lower TI vs higher TI mean?

A

Lower TI - Drug is less effective, more risky to use
Higher TI - More effective, potentially more ideal for use in a patient

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23
Q

Different patient conditions can affect which drug is better to use. True or False?

A

True

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24
Q

What is something you’d want to consider in antimicrobial treatments?
HINT: Pertaining to amount

A

Intent to target small or large number of different microbes

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25
Q

Why would you want to get rid of specific bacteria, but keep the rest?

A

You may not want to disrupt the natural healthy microbiome

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26
Q

What are antibiotics with a wide range of targets called?

A

Broad-Spectrum Antibiotics

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27
Q

What are antibiotics with a small range of targets or organisms called?

A

Narrow-Spectrum Antibiotics

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28
Q

When is a Broad-Spectrum Antibiotic likely to be used?

A

Frequently used without properly identifying the organism, because the antibiotic is likely to kill whatever it is

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29
Q

When is a Narrow-Spectrum Antibiotic likely to be used?

A

More effective on specific organisms, but requires more knowledge of specific infections

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30
Q

What is the ‘ideal’ antimicrobial? (NOT all 9 of its qualities)

A

Selectively toxic, meaning it only acts on bad bacteria

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31
Q

What are antibiotics abbreviated as?

A

Abx

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32
Q

What are the 5 targets of antibiotics?

A
  1. Cell wall synthesis
  2. DNA Structure and Function
  3. Protein synthesis
  4. Cytoplasmic membrane structure and function
  5. Folic acid synthesis
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33
Q

What does not exist in human cells and is a good target for antimicrobial drugs?

A

Peptidoglycan

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34
Q

What are Beta-Lactams?

A

Class of antibiotics that specifically target the process of cell wall synthesis and repair

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35
Q

What are enzymes that are bound by penicillin and other beta-lactams called?

A

Penicillin-Binding Proteins (PBPs)

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36
Q

What kind of inhibitor is a Beta-Lactam? Why?

A

Competitive Inhibitor

Prevents creation of peptide bridges in the last step of peptidoglycan synthesis

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37
Q

What is cell division like with vs without Beta-Lactams?

A

With: Expanding cell wall does not fully connect, so cell growth spills out of cell wall
Without: Cell wall construction proceeds and each cellular division occurs normally

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38
Q

What is the most famous Beta-Lactam?

A

Penicillin

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39
Q

What are Abx from the Penicillin family paired with? Why?

A

Clavulanic Acid

Increases efficacy of penicillins in bacteria that are naturally resistant

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40
Q

What is the combination of clavulanic acid and Amoxicillin called?

A

Clavamox

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41
Q

Name 2 groups of Beta-Lactams

A
  1. Penicillin-Binding Proteins (PBPs)
  2. Cephalosporins
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42
Q

How are Cephalosporins sometimes classified?

A

‘Generation’ - Based on discovery timeline

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43
Q

How are newer generations of Cephalosporins better? How are they worse?

A

Increased efficacy against gram-negative organisms
Decreased efficacy against gram-positives (sometimes)

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44
Q

What is a commonly used drug that can be used to treat skin infections called?

A

Bacitracin

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45
Q

Bacitracin is NOT one of the ingredients in Neosporin. True or False?

A

False

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46
Q

What treats Staphylococcus infections that are resistant to penicillin and methicillin, or in patients allergic to penicillin?

A

Vancomycin

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47
Q

Vancomycin targets a ______ _______ in peptidoglycan synthesis

A

different enzyme

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48
Q

What is Vancomycin commonly used against?

A

Methicillin Resistant Staphylococcus aureus (MRSA)

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49
Q

What is used to treat Mycobacterium tuberculosis infections? Is its target peptidoglycan?

A

Isoniazid; No

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50
Q

What does Isoniazid do?

A

Stops synthesis of Mycolic Acid

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51
Q

Isoniazid is _____________ in rapid-growing Mycobacterium populations. Isoniazid is _____________ in slow-growing Mycobacterium populations.

A

Bactericidal; Bacteriostatic

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52
Q

Is Isoniazid Broad or Narrow Spectrum? Why?

A

Narrow Spectrum as it targets Mycobacterium, regardless of the two effects it can produce

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53
Q

Are our ribosomes different from bacterial ribosomes?

A

Yes

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54
Q

What are 2 important factors to consider when it comes to Protein Synthesis Blockers?

A
  1. Only bacterial processes are blocked
  2. Find things that target bacterial ribosomal subunits
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55
Q

What are 3 steps of protein synthesis that can be targetted?

A
  1. Correct “reading” of RNA codons
  2. Attachments of tRNAs as they enter the ribosomes
  3. Movement of the ribosome along the mRNA
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56
Q

Name 2 Protein Synthesis Blockers

A
  1. Aminoglycosides
  2. Macrolides
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57
Q

Name 1 Aminoglycoside

A

Streptomycin

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58
Q

What do Aminoglycosides do?

A

Attach to ribosomal subunit

59
Q

When an Aminoglycoside attaches to a ribosomal subunit, what 3 things can it cause the ribosome to do?

A
  1. Prevents it from fully assembling or causes it to assemble into a slightly-wrong shape
  2. Can make it different to transfer growing polypeptide, leading to an incomplete protein
  3. Can cause misreading of the mRNA, which causes bacteria to produce ‘wrong’ proteins
60
Q

What kind of antibiotics are targeted by Aminoglycosides?

A

Gram-negative rods

61
Q

What blocks the ‘entry’ of tRNA to the ribosome?

A

Tetracycline

62
Q

When tRNA entrance is blocked to the ribosomes, what occurs?

A

Protein synthesis slows down or stops

63
Q

Name 2 Macrolides

A
  1. Erythromycin
  2. Azithromycin
64
Q

What do Macrolides bind to?

A

50S Ribosomal Subunit

65
Q

What 2 steps do Macrolides block?

A
  1. Blocks movement of ribosome along the mRNA
  2. Blocks transfer of growing polypeptide from one tRNA to the next
66
Q

When a Macrolide successfully blocks a step, what happens to translation?

A

Translation slows down or stops

67
Q

What TYPE of antibiotic is a macrolide? Is it reversible?

A

Bacteriostatic; Yes, it’s reversible

68
Q

What is an intermediate in the synthesis of Nitrogenous Bases and certain Amino Acids?

A

Folic acid (Folate or Vitamin B9)

69
Q

What is necessary for DNA and RNA production?

A

Folic acid

70
Q

What are competitive inhibitors to enzymes in the Folic Acid synthesis pathway?

A

Sulfonamides

71
Q

What can inhibiting folic acid biosynthesis lead to?

A

Slowdown or total stop of cell cycle and cellular processes

72
Q

Sulfonamides block what processes? What does it not block?

A

Bacterial, NOT human processes

73
Q

What targets DNA unwinding enzymes?

A

Fluoroquinolones

74
Q

Provide 1 example of a DNA unwinding enzyme

A

Gyrase

75
Q

What happens when a DNA unwinding enzyme is targeted by a Fluoroquinolone? Is this process bactericidal or bacteriostatic?

A

DNA Replication cannot occur; Bactericidal

76
Q

A Fluoroquinolone’s effects vary in _____________ bacteria and _____________ bacteria

A

Gram-positive & Gram-negative

77
Q

Name 1 Fluoroquinolone

A

Ciprofloxacin

78
Q

What inhibits bacterial RNA Polymerase?

A

Rifampin

79
Q

When RNA Polymerase in bacteria is inhibited, what occurs?

A

Elongation in transcription never happens past 2nd or 3rd nucleotide, so no usable mRNA is made

80
Q

Why is Rifampin not used against Gram-Negative bacteria?

A

Does not pass through outer membrane effectively

81
Q

What antibiotic interacts with membrane phospholipids?

A

Polymyxin

82
Q

When Polymyxin is used, what ends up occurring in cells?

A

Distortion of cell shape and causes leakage of cytosol

83
Q

What kind of bacteria is Polymyxin particularly effective against? Why?

A

Gram-negative bacteria

Rely on membrane for shape and stability

84
Q

What kind of bacteria can MAKE Polymyxin? It’s another ingredient in ____________

A

Gram-positive bacteria; Neosporin

85
Q

List 3 reasons why non-bacterial infections are more challenging to treat than bacterial ones

A
  1. Fewer Broad-Spectrum strategies, since infectious organisms may be completely different from each other
  2. Most research has been done on anti-bacterial treatments
  3. Are Eukaryotic infections, so higher risk of damaging human processes
86
Q

In antifungals, what do macrolide polyenes bind to?

A

Steroids on fungal membranes

87
Q

When antifungals macrolide polyenes are binded to steroids, what occurs within the cells?

A

Fungal membranes are more fluid causing leakage of potassium and sodium ions

88
Q

The steroids that antifungal macrolide polyenes bind to is the same kind as in human cells. True or False?

A

False

89
Q

What inhibits the enzymatic pathway that makes fungal steroids? What happens to the fungi?

A

Azoles and Allylamines

Fungi can’t grow

90
Q

What inhibits cell wall synthesis in fungi? What are fungal cell walls made of?

A

Echinocandins; Chitin

91
Q

Does Chitin appear in humans?

A

No

92
Q

What is a key group of drugs used to combat malaria that are derived from bark of certain trees?

A

Quinines

93
Q

Quinine molecules are bitter and historically very effective at __________ malaria

A

Preventing

94
Q

What is another antimalarial drug that is NOT Quinines? It was used for centuries by what culture?

A

Artemisinin; Chinese medicine

95
Q

The discovery of Artemisinin earned who a Nobel Prize in medicine in 2015?

A

Tu Youyou

96
Q

What is the main challenge of antihelminthic drugs?

A

Helminths are not single-celled organisms

97
Q

What are the 2 MAIN targets for antihelminthic drugs? What occurs when these targets are affected?

A
  1. Worm musculature (Pyrantel) - Worm can’t hold on to your digestive tract and is expelled
  2. Worm’s cell membrane (Ivermectin) - Causes paralysis in the worm
98
Q

What is an alternative target to the main 2 in antihelminthic drugs?

A

Targets worm’s symbiotic bacteria

99
Q

What is a naturally occurring phenomenon that is an emerging challenge in clinical settings?

A

Antibiotic resistance

100
Q

What are 2 ways that bacteria have antibiotic resistance?

A
  1. Antibiotics can be produced by bacteria, which must be resistant to those same compounds
  2. Some have naturally-occurring resistance, while some develop a resistance
101
Q

Some organisms develop or acquire new __________ that help them ______________ or ______________

A

Enzymes; Deactivate or break down drugs

102
Q

What are enzymes that break down compounds like Penicillin?

A

Beta-Lactamases

103
Q

If an organism can change its _____________, what happens to drugs?

A

Permeability; drugs may be less able to go in and affect cellular function

104
Q

Why do changes in bacterial permeability occur frequently?

A

Mutation in receptor proteins

105
Q

Organisms can acquire ___________, which will do what?

A

New proteins; pump drug out of the cell after it comes in, preventing it from affecting cellular functions

106
Q

____________ for drugs can ____________________________________________________
HINT: Where drugs attach to

A

Binding sites; change due to mutation, meaning target may no longer be susceptible

107
Q

How can a bacteria circumvent a drug’s target? What happens when these are used?

A

Alternative pathways can be used

Ex: If Folic acid can NOW be synthesized, sulfa drugs will no longer work

108
Q

How do antibiotic resistances arise? It is especially true for what kind of drug?

A

Mutation can change bacteria’s proteins just enough to make an antibiotic not function

Especially true for drugs that target enzyme’s active site

109
Q

What is the process in which bacteria can acquire new genes called?

A

Horizontal Gene Transfer

110
Q

What happens once a bacteria has the ability to resist a drug exists? Over a short period of what time, what happens to living cells in survivors?

A

Gains fitness advantage, making it more likely it will survive and reproduce

All living cells will be descended from survivors, so they will all have ability to survive

111
Q

What is the introduction of genetic material from one organism to another organism within the same generation?

A

Horizontal Gene Transfer

112
Q

What are the 3 methods of Horizontal Gene Transfer? What does each one entail?

A
  1. Transformation - Direct pick-up of DNA from the environment
  2. Transduction - Transfer of DNA by a bacteriophage
  3. Conjugation - Transfer of DNA from one cell to another
113
Q

Within transformation, where/what kind of DNA is picked up (list 3)?

A
  1. Plasmid DNA
  2. Chromosomal DNA
  3. Can be from any donor
114
Q

Can all cells use Transformation as a method of Horizontal Gene Transfer?

A

No

115
Q

What kind of cells can use Transformation? What do they need in order to BE a competent cell

A

Competent cells; Surface proteins that can recognize and take up DNA from the environment

116
Q

Can you force cells to become competent? List an example

A

Yes; E.Coli DH5(alpha) in lab

117
Q

How can we force cells to become competent?

A

Temperature and salt to change surface properties

118
Q

Who was the first person to identify Transformation and what year did they identify it in?

A

Frederick Griffith 1928

119
Q

Originally, Griffith was trying to develop a vaccine for what bacteria? How many strains was he working with?

A
  1. Streptococcus pneumonia
  2. 2
120
Q

What are 2 characteristics of a S (smooth) Strain?

A
  1. Have capsule that allows them to escape host immune system
  2. Virulent
121
Q

What are 2 characteristics of a R (rough) Strain?

A
  1. Does not have capsule, so cannot escape host immune system
  2. Avirulent
122
Q

What were the 4 ways Griffith carried out his experiment and what were the results? What was the 5th step/reason for the 5th step?

A
  1. Live cells of S-strain was injected into mouse - Mouse dies
  2. Dead (heat-treated cells) of S-strain injected into mouse - Mouse lives
  3. Live cells of R-strain injected into mouse - Mouse lives
  4. Dead (heat-treated) S-strain cells and live R-strain cells injected into mouse - Mouse dies
  5. Streptococcus isolated and cells with capsules are identified
123
Q

What does the Griffith Experiment show?

A

Live R-strain + Dead S-strain (both avirulent) ——> R-strain was transformed to S-strain (virulent)

124
Q

What is a bacteriophage?

A

Bacteriophage

125
Q

In transduction, DNA is transferred from one cell to another by?

A

Bacteriophage

126
Q

Name the 4 stages of a Bacteriophage’s life cycle

A
  1. Attach to bacterial surface and inject viral DNA and enzymes
  2. Cut up host chromosome to disable it
  3. Host enzymes are used to replicate viral DNA and make more phage particles
  4. Host cell bursts and new bacteriophages released to environment
127
Q

Describe the last step of the bacteriophage life cycle IN DETAIL

A

Packages genome into protein shell, which will be able to infect another cell

128
Q

What is Transduction in bacteriophages?

A

Consequence of a mistake in last step of bacteriophage life cycle

129
Q

What happens during Transduction in bacteriophages?

A

Newly-made bacteriophage accidentally packages host’s bacterial DNA instead of viral DNA, so when bacteriophage infects new cell - new cell receives bacterial DNA instead

130
Q

What is conjugation?

A

Direct transfer of DNA from one living cell to another using a pilus

131
Q

What is a ‘tunnel’ between two cells that connect their cytoplasms?

A

Pilus

132
Q

To form a pilus, a special gene is needed. What is this gene called?

A

F-Factor

133
Q

Where are 2 possible places an F-Factor can be found?

A
  1. Plasmid
  2. Bacterial chromosome of HFR cells
134
Q

When an F-factor is found on a plasmid, what is it called?

A

F-plasmid

135
Q

What does HFR in HFR cells stand for?

A

High Frequency of Recombination

136
Q

How do rapidly-changing organisms have new clinical significance?

A

Bacteria can acquire new virulence factors

137
Q

What makes Anthrax such a lethal disease?

A

Its toxin

138
Q

Bacillus anthracis is similar to Bacillus cereus. What is the defining factor(s) in Bacillus anthracis that sets it apart from Bacillus cereus?

A

Contains plasmids encoding toxins and immune-system evasion methods

139
Q

What toxin does Vibrio cholerae make?

A

Cholera Toxin

140
Q

What is the primary cause for symptoms of Cholera?

A

Its toxin

141
Q

What does Vibrio cholerae produce and what is it carried by?

A

Toxin carried by filamentous CTX phage (bacteriophage)

142
Q

Some strains of E.Coli have acquired _________

A

toxin-producing genes

143
Q

What other bacteria did E.Coli get its set of toxin-producing genes from? Which method did it use to acquire this set?

A

Shigella dysenteriae; Conjugation

144
Q

What disease can the toxin from E.Coli lead to? What are the MAJOR symptoms that can be caused by this disease?

A

Hemolytic uremic syndrome; Kidney failure and death

145
Q

Clavamox is a combination of what 2 drugs?

A

clavulanic acid and Amoxicillin

146
Q

What 2 drugs are used alongside each other to treat Tuberculosis?

A

Rifamp and Isoniazid

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