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NURS 2228 - Microbiology > Midterm #2 Material > Flashcards

Midterm #2 Material Flashcards

1
Q

Define prophylaxis

A

Use of a drug to prevent potential for infection of a person at risk

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2
Q

Define chemotherapeutic drug

A

Any chemical used in the treatment, relief, or prophylaxis of a disease

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3
Q

Define Antimicrobial

A

All inclusive terms for an antimicrobial drug

- regardless of its origin

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4
Q

Define Antibiotics

A

Substance that can inhibit or destroy other microorganisms

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5
Q

What is the difference between antimicrobial and antibiotics?

A

a

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6
Q

What are narrow spectrum antimicrobials?

A

Antimicrobials effective against a limited array of microbial types

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7
Q

What are broad spectrum antimicrobials?

A

Antimicrobials effective against a wide variety of microbial types

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8
Q

What is monotherapy?

A

Treatment using a single drug

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9
Q

What is combined therapy?

A

Treatment using more than one drug

drugs could be contained in the same pill

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10
Q

Define bacteriostatic agents

A

Agents that inhibit or prevent the growth of bacteria

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11
Q

Define disinfection

A

Physical or chemical process that destroys vegetative pathogens
- but NOT bacterial endospores

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12
Q

Define antiseptic

A

Chemical applied to living tissues to render them free of pathogens

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13
Q

Define sanitization

A

Forceful cleaning that removes contaminants and makes objects hygienic and safe for use

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14
Q

How do autoclaves sterilize objects?

A

Utilize steam under pressure to sterilize heat-resistant materials

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15
Q

How does pasteurization disinfect?

A

Subjects liquids to temperatures below 100 degrees C and is used to lower the microbial load in liquids

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16
Q

What does it mean to say that an antimicrobial has a selective toxicity?

A

Means that it is effective against the microbes without harming the host

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17
Q

What does it mean to say that an antimicrobial has selective toxicity?

A

Means that it is effective against the microbes without harming the host

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18
Q

True or False:

It is more beneficial to have an antimicrobial drug that is microbistatic instead of microbicidal

A

False!

  • it is better to have microbicidal
  • “static” means that you prevent the growth, not kill the organism
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19
Q

What does actinomycin interfere with?

A

Interferes with the synthesis of nucleic acid AND proteins

  • in bacterial AND human cells
  • NOT selectively toxic
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20
Q

Why do we hold off on giving honey to kids under 1 year old?

A

Interferes with normal development

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21
Q

True or False:

Selective toxicity is a characteristic of antimicrobials

A

True

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22
Q

How do antibiotics work against microbials (2)?

A
  1. By inhibiting one or more steps in the synthesis of essential cellular components
  2. Increasing permeability of microbial cell membrane
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23
Q

What are 5 examples of major actions that antibiotics can work on against microbials?

A
  1. Cell wall inhibitors
  2. Cell membrane
  3. DNA/RNA
  4. Protein synthesis inhibitors acting on ribosomes
  5. Metabolic pathways and products
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24
Q

True or False:

Drugs can target the ribosomes of the bacterial proteins

A

True

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25
Q

What do cell wall inhibitors prevent?

A

Cross-linkage between the two key polymer carbohydrates in the peptidoglycan

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26
Q

What gives bacteria their cell shape and integrity?

A

Peptidoglycan

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27
Q

What examples of beta-lactam antibiotics (2)?

A
  1. Penicillin (ex: Ampicillin and Amoxicillin)

2. Cephalosporins (methicillins, vancomycins, and isoniazid)

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28
Q

What is a characteristic of beta-lactam antibiotics?

A

Class of broad spectrum antibiotics

- contains a beta-lactam ring in their molecular structure

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29
Q

What drug is the last resort for treating gram-positive bacterial infections not responsive to other drugs?

A

Vancomycin

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30
Q

What is the first line drug for TB?

A

Isoniazid (INH)

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31
Q

How do antibiotics disrupt the cell membrane/permeability and/or function?

A

The drugs bind to the microbial cell membrane leading to alteration in membrane permeability and cell death

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32
Q

What is amphotericin B used for?

A

Life threatening fungal infections

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33
Q

What the group of polymyxin antibiotics used for?

A

Primarily for gram-negative bacterial infections

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34
Q

What is the common drug in over the counter antibiotics that disrupt the cell membrane in gram-negative bacteria?

A

Polymyxin B

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35
Q

What is an example of a last resort drug that is used to disrupt the cell membrane of gram-negative bacteria?

A

Polymyxin E

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36
Q

True or False:

Polymyxin B is more potent than Polymyxin E

A

False!

- E is more potent than B

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37
Q

What do antibiotics do to inhibit nucleic acid synthesis?

A

Block synthesis of microbial DNA or RNA

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38
Q

What does Fluoroquinolone (Ciprofloxacin) do?

A

Inhibits two enzymes required for DNA replication
- inhibits nucleic acid synthesis
(1 of the major actions of antibiotics)
- UTIs and healthcare associated pneumonia

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39
Q

What does rifampin (rifampicin) do?

A

Inhibits RNA polymerase (enzyme required to produce all types of RNA in bacteria)
- used as part of COMBINED therapy to prevent/treat TB and meningitis

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40
Q

What are the two examples of drugs (antibiotics) that inhibit nucleic acid synthesis?

A
  1. Fluoroquinolone (Ciprofloxacin)

2. Rifampin (Rifampicin)

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41
Q

How do antibiotics block protein synthesis on microbial agents?

A

Target ribosomes at various stages of protein synthesis

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42
Q

Aminoglycosides effectively block the protein synthesis of what kinds of bacteria?

A

Most gram-negative aerobic and facultative anaerobic rod-shaped bacteria

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43
Q

What is erythromycin used for specifically in blocking protein synthesis?

A

For skin and upper respiratory infections

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44
Q

Linezolid effectively blocks the protein synthesis of what kinds of bacteria?

A

Most gram-positive bacteria

- including MRSA and VRE

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45
Q

How do antibiotics inhibit metabolic pathways?

A

They work by competitive inhibition

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46
Q

Sulfamethoxazole-trimethoprim (SMZ-TMP) is used to treat? And to inhibit the metabolic pathway of what?

A

Used to treat pneumonia

- caused by the protozoan PNEUMOCYSTIS in HIV/AIDS patients

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47
Q

What is the role of sulfonamide and trimethoprim in the inhibition of metabolic pathways?

A

Interferes with the metabolic pathways for production of essential nutrients (such as folic acid)

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48
Q

What is the important role that folic acid plays in protein synthesis?

A

It’s a coenzyme for the DNA and RNA synthesis

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49
Q

True or False:

Trimethoprim is bacteriostatic when used alone but bactericidal when used WITH sulfonamide

A

TRUE!

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50
Q

What are the major mechanisms of antivirals?

A
  1. Protecting host cells from being infected (interferons)
  2. Enhancing the host defense against viruses (transfer of antibodies from immune person to the susceptible person)
  3. Interfering with specific steps of the viral replication cycle
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51
Q

True or False:

Even though interferons help protect the host cell from being infected, they do have some toxic effects

A

True

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52
Q

What three drugs inhibit the release or virus entry?

A
  1. Fuzeon
  2. Amantidine
  3. Tamiflu
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53
Q

What are three drugs that inhibit the synthesis of nucleic acid of viruses?

A
  1. Acyclovir (Herpes)
  2. Nucleotide analog reverse transcriptase (RT) inhibitors (HIV)
  3. NON-nucleoside reverse transcriptase inhibitors
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54
Q

Describe a retrovirus

A

2 strands of RNA

- use reverse transcription to form DNA (uses the enzyme reverse transcriptASE)

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55
Q

What is an example of a drug that inhibits the assembly of viruses?

A

Protease inhibitors (HIV)

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56
Q

What does combined therapy do for persons infected with HIV (3)?

A
  1. Reduces viral load
  2. Restores immune function
  3. Reduces the emergence of drug-resistant HIV
    - does NOT cure!
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57
Q

What are antibiotics?

A

Natural substances produced by one microbe (bacteria, fungi, protozoa) that inhibits the growth or kills other microorganisms

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58
Q

True or False:

Antibiotics work well on viruses

A

FALSE

- antibiotics do NOT work on viruses

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59
Q

What are antimicrobials?

A

Chemotherapeutic agents against viruses (antivirals) and other types of microbes (antibiotics)

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60
Q

True or False:

Antibiotics can be useful against a narrow or broad group of microbes

A

True

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61
Q

What does the suffix “-static” mean?

A

Inhibit growth

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62
Q

What does the suffix “-cidal” mean?

A

Kill

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63
Q

What is the action of penicillin?

A

Inhibits the synthesis of peptidoglycan (found only in bacteria but not human cells)
- has desirable selective toxicity

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64
Q

What is the action of actinomycin?

A

Does NOT have selective toxicity

- inhibits the synthesis of nucleic acids/protein synthesis on BOTH bacteria and human

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65
Q

If you are exposed to HIV (needle stick injury) what is the post-exposure prophylaxis?

A

Tenofovir (300 mg QD)
+ Lamivudine (150 mg BID)
+ Kaletra (2 tabs (BID)

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66
Q

What is asepsis or septic technique?

A

Practice of preventing or minimizing the risk of introducing microbes into key sterile equipment parts

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67
Q

What is an aseptic field?

A

An area created to control the environment around the procedure to protect the key parts

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68
Q

What is the ANTT approach (6 steps)?

A
  1. Risk assessment
  2. Mange the environment
  3. Decontaminate and protect
  4. Use aseptic fields
  5. Use non-touch technique
  6. Prevent cross infection
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69
Q

Define sterile

A

State of being free (or absence) of all viable microorganisms
- including bacterial spores

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70
Q

Define sterility testing

A

IN VITRO test to check for any contamination to ensure any injectable drugs must be sterile

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71
Q

Define sterilization

A

Destruction of ALL VIABLE life form

  • including bacteria spores
  • by physical or chemical means
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72
Q

Define disinfection

A

Destruction of microorganisms (esp. pathogens) by physical or chemical means
- NOT effective against bacterial spores

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73
Q

Define antisepsis

A

Similar to disinfection but applied to LIVING TISSUES

- reduce/remove resident skin microbiota before surgery and injection

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74
Q

Define decontamination

A

Applies to BOTH living and non-living objects

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75
Q

What are the three major modes of action to control microbiota?

A
  1. Protein denaturation
  2. Permanent damage to microbial nucleic acids
    - including their genome
  3. Destruction of structural integrity of microbes
    - damaging bacterial cell wall and/or cell membrane
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76
Q

What are critical items?

A

Items that enter sterile tissue or vascular space

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77
Q

What is applied to semi-critical items (does not penetrate the bloodstream)?

A

Disinfection

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78
Q

What can be used to disinfect an entire building?

A

Chlorine dioxide

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79
Q

What does a TYPICAL ANTT approach to prevent cross infection include?

A
  1. Environmental risk assessment
  2. Decontamination and protection
  3. Aseptic field selection and management
  4. Non-touch technique
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80
Q

What are the factors influencing the efficacy of disinfecting and sterilizing agents (death rate) (6)?

A
  1. Number of microbes present
  2. Nature of microbes present (ex: spores)
  3. Temp and pH
  4. Concentration (dosage or intensity) of agent used
  5. Modes of action of the agent (microbistatic or microbicidal)
  6. Presence of contaminants (blood/mucus)
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81
Q

What are two methods of sterilization using heat?

A
  1. Dry heat

2. Moist heat

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82
Q

How hot and how long do you have use dry heat for to have sterilization?

A

160 degrees

2 hours

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83
Q

How hot and for how long do you have to use moist heat for to have sterilization?

A

121 degrees
15 min
- 15 psi/pound per squared inch in an autoclave

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84
Q

True or False:

If you increase the heat during sterilization, you can reduce the time it takes

A

True

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85
Q

What is the method called if you use high energy (short wavelength) radiation to sterilize?

A

Ionizing radiation

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86
Q

What are the benefits of using ionizing radiation (3)?

A
  • strong penetrating power
  • causes permanent damage to nucleic acid
  • can be used on heat-sensitive items
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87
Q

What is the most commonly used sterilization method in healthcare settings?

A

Ethylene Dioxide (gas)

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88
Q

What does ethylene dioxide do and what is it used for?

A

Blocks DNA replication and enzymatic functions

- used for sterilizing heat-sensitive, delicate instruments

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89
Q

What are the characteristics of using ultraviolet light to disinfect?

A
  • Non-ionizing radiation

- Exposure to UV leads to the formation of thymine dimers

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90
Q

True or False:

Ultraviolet light has less energy and less penetrating power than ionizing radiation

A

True

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91
Q

What does ultraviolet light do?

A

Blocks normal DNA replication

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92
Q

True or False:

Bacteria cannot repair the DNA damage cause by UV light

A

FALSE!

- SOME microbes CAN repair the DNA damage caused by UV light

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93
Q

What is used for air and water disinfection?

A

UV light

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94
Q

What is the agent that is used for antisepsis and disinfection?

A

Iodine

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95
Q

What are the benefits of using iodine?

A
  • strong oxidizing agent
  • good penetrating power
  • rapid action
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96
Q

What is the preferred method of cleaning your hands when they are visibly soiled?

A

Soap and water

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97
Q

What does soap contain that reduces the surface tension between a liquid and a solid?

A

Surfactant molecules

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98
Q

What antimicrobial agent might be contained in soap?

A

Chlorhexidine

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99
Q

What are the benefits of using an alcohol based hand rub?

A
  • takes less time than hand washing
  • more effective than hand washing when hands are NOT visibly soiled
  • less drying
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100
Q

True or False:

It is preferred to use soap and water when dealing with C. diff

A

True

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101
Q

True or False:

Studies have not shown a decrease of MRSA and VRE associated with the use of alcohol-based hand rub

A

FALSE

- studies did show a decrease of MRSA and VRE associated with the use of ABHR

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102
Q

Rank the following 8 agents in terms of their resistance ( 1 = most resistant; 8 = least resistant):
Bacterial spores, enveloped viruses, fungi, gram + bacteria, gram - bacteria, non-enveloped viruses, prions, protozoa cysts

A
  1. Prions
  2. Endospores of bacteria
  3. Protozoa cysts
  4. Gram - bacteria
  5. Fungi
  6. Non-enveloped viruses
  7. Gram + bacteria
  8. Enveloped viruses
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103
Q

What does the binomial nomenclauture of bacteria consist of?

A
  1. Genus

2. Species

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104
Q

What 4 things can bacteria be classified and grouped into?

A
  1. Family
  2. Genus
  3. Species
  4. Subspecies
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105
Q

True or False:

There could be a single or many species within a genus

A

True

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106
Q

If bacteria are members of the same species, what are the three ways that they can be classified in terms of strains?

A
  1. Biotypes
  2. Phage types
  3. Serotypes
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107
Q

What is an example of a biotype of bacteria?

A

Resistant to antibiotics

- such as MRSA

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108
Q

How are different strains of serotypes differentiated by?

A

Based on the use of antibodies or serum

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109
Q

How can different strains of bacteria of the same species differ

A
  1. Communicability
  2. Reservoirs and modes/routes of transmission
  3. Vaccine (preventability)
  4. Diagnostics
  5. Susceptibility to antimicrobials
  6. Virulence
  7. S/S of diseases
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110
Q

What are the names of the different groups of meningococcal?

A 
A
B
C
Y
W-135
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111
Q

What happens if you are vaccinated with meningococcal polysaccharide vaccine, Groups A, C, Y and W-135?

A

You are protected against all of them

- EXCEPT group B!

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112
Q

What are the S/S associated with different escherichia coli serotypes?

A
  • urinary frequency
  • dysuria
  • hematuria
  • pyuria
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113
Q

Why is the microscope an essential tool?

A

To examine and study microbes and cellular structures

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114
Q

What are the two major types of microscopes?

A
  1. Light

2. Electron

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115
Q

A microscope will have a better resolving power, if ________

A

It has a smaller value of resolution

- shortest distance between 2 points on a specimen

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116
Q

What kind of microscope has a high magnification (light or electron)?

A 
Electron = 1,000,000 x or more
Light = only 2,000 x
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117
Q

What is the maximum resolution of a light microscope?

A

200 nm

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118
Q

What is the maximum resolution of an electron microscope?

A

0.5 nm

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119
Q

What kind of microscope is required to study viruses or cellular details?

A

Electron microscope

120
Q

True or False:

An electron microscope has greater magnification and better resolution than a light microscope

121
Q

What kind of microscope is commonly used with staining methods, to identify disease-causing microbes?

A

Light microscope

  • gram-stain
  • but NOT viruses or prions
122
Q

Why do gram stains not work well with some bacteria?

A

B/c they have ATYPICAL cell walls

123
Q

If a bacteria has an ATYPICAL cell wall, what kind of stain can be used to identify them?

A

Acid-fast stain

124
Q

What are two examples of bacteria that need an acid-fast stain to identify them?

A
  1. Nocardia

2. Mycobacterium (TB and leprosy)

125
Q

What is nocardia?

A

Opportunistic infection of the lungs, heart and brain

126
Q

What is obtained as part of the conventional approach in identifying disease-causing bacteria?

A

Bacterial morphology - shape

127
Q

True or False:

Bacterial cell shapes and their arrangement cannot be revealed under microscope examination

A

False

- obviously it can be

128
Q

What are the three most common shapes of bacterial cells?

A
  1. Coccus/cocci
  2. Bacillus/bacilli
  3. Spiral (vibrio and spriochete)
129
Q

Describe the coccus/cocci shape

A

Berry-shaped

130
Q

Give three examples of bacteria that have the coccus/cocci shape

A
  1. Staphylococcus
  2. Stroptococcus
  3. Enterococcus
  4. Neisseria
131
Q

Describe the bacillus/bacilli shape

132
Q

Give 4 examples of bacillus/bacilli shaped bacteria

A
  1. Bacillus
  2. Lactobacillus
  3. E. coli
  4. Clostridium
133
Q

Describe the Vibrio (spiral) shape

A

Comma-shaped or short-curved rod

134
Q

Give 2 examples of vibrio shaped bacteria

A
  1. Vibrio

2. Campylobacter

135
Q

Describe the spirochete (spiral) shape

A

Corkscrew-shaped

136
Q

What are 2 examples of spirochete (spiral) bacteria?

A
  1. Borrelia (Lyme disease)

2. Treponema (syphillis)

137
Q

What environment conditions need to be optimal for bacterial growth (5)?

A
  1. Oxygen
  2. pH
  3. Water
  4. Nutrients
  5. Temperature
138
Q

What are the 4 ways that bacterial growth can be limited or controlled?

A
  1. Use of chemicals and/or physical methods of control
  2. Antibiotics
  3. Immune responses by host (enhanced by vaccination)
  4. Microenvironment of bacteria
139
Q

True or False:

Bacteria growth is infinite and constant

A

False

- it’s not …

140
Q

What are the 4 phases of bacteria growth?

A
  1. Lag phase
  2. Exponential (log) phase
  3. Stationary phase
  4. Death phase
141
Q

What happens in the lag phase of bacteria growth?

A

Bacteria are adjusting to the environment (pH, temp, acidity, etc)

  • there is not a lot of growth
  • just some growth
142
Q

What happens in the exponential growth phase of bacteria growth?

A

Numbers rise steeply

  • bacteria are actively multiplying
  • generation time or doubling time
143
Q

What happens during the stationary phase of bacteria growth?

A

Rate of growth equals the rate of dealth

- bacteria are competing for limited resources

144
Q

What happens during the death phase of bacteria growth?

A

More bacteria are dying than the reproduction rate

145
Q

At what phase of growth are bacteria most susceptible to antibiotics?

A

Exponential (log) phase

146
Q

Give a reason why the growth rate equals the death rate during the stationary phase

A

Due to micro-environmental factors

- lack of nutrients, pH changes, toxic metabolites, etc

147
Q

How does asexual reproduction occur?

What does it produce?

A

Binary fission

- a parent cells give rise to two identical daughter cells

148
Q

What is important to keep in mind with asexual reproduction and resistance?

A

Daughter cells inherit EVERYTHING from parent cell

- this includes RESISTANCE to antibiotics!

149
Q

What is the doubling time or generation time?

A

Time it takes for a bacterial population to double its number

150
Q

What is the generation time of E. coli?

A

15 - 20 min in the lab

- 12 - 24 hours in the intestine

151
Q

What is the generation time for mycobacterium tuberculosis?

A

12 - 20 hours in the LAB

152
Q

What is the formula for bacteria reproduction?

A

Nt = No x 2^n

Nt = number of bacteria at time, t
No = number of bacteria at time o (starting number)
n = number of generations in time, t
153
Q

If bacteria are fast-growing, they have a _____ generation time

154
Q

If bacteria are slow-growing, they have a ____ generation time

155
Q

Why are fast-growing bacteria more susceptible to antibiotics?

A

B/c antibiotics act in the exponential growth phase

- more likely that you are going to catch more bacteria during this phase

156
Q

Why is it a problem if a patient’s wound is contaminated with a fast-growing bacteria?

A

A small number could result in a large bacterial population

157
Q

For fast-growing bacteria, what is needed to stop the infection in patients?

A

Prompt diagnosis and timely interventions

158
Q

True or False:

Slow-growing bacteria are less susceptible to antibiotics

A

True

- antibiotics affect bacteria during their growth

159
Q

If a patient is infected with a slow-growing bacteria, how long will the antimicrobial therapy usually take?

A

Longer duration of therapy

- when compared to a fast-growing bacteria

160
Q

Why might a patient stop their antimicrobial treatment if they are infected with a slow-growing bacteria?

A

It requires a LONG treatment plan, and the patient may no longer feel sick
- might lead to re-infection

161
Q

Using the formula:
Nt = No x 2^n
Calculate the number of bacteria in a patient’s wound at the end of 5 hours after it was contaminated by a HCW with 1,000 bacteria with a generation time of 30 minutes, assuming the growth conditions for the bacteria are optimal

A 
No = 1,000
T = 5 hours
G = 30 minutes
Number of generations = 10 
(5 x 60 minutes)/30 mins

Nt = 1,000 x (2^10)
Nt = 1,024,000
162
Q

Define antibiotic resistance

A

Lost the ability to effectively control bacterial growth or kill bacteria

163
Q

True or False:

Antibiotic resistant bacteria continue to grow and multiply in the presence of therapeutic dose of the drug

A

True

- because they have developed resistance, so the drug is not stopping their growth

164
Q

What are the 4 major mechanisms of antibiotic resistance?

How do they do it?

A
  1. Alteration of target site
  2. Efflux pumps
  3. Enzymatic degradation or modification
  4. Altered permeability
165
Q

How do efflux pumps work to increase antibiotic resistance?

A

Bacteria cells have active pumps that pump the drug out of their cells
- if the drug is not in their cell, it cannot be effective

166
Q

How does enzymatic degradation or modification work to increase antibiotic resistance?

A

Bacteria cells would create enzymes that degrade or breakdown the drug

167
Q

What can some bacteria produce that degrade drugs such as penicillin and cephalosporins?

A

B-lactamases

168
Q

Describe the action of B-lactamases

A

Destroys the B-lactam ring structure (active site of the drug) which binds to penicillin-binding proteins

169
Q

What happens if an antibiotic resistant bacteria has altered permeability?

A

Permeability to antibiotics is altered

- makes the cell impermeable or very hard to permeate

170
Q

What are the 3 ways that the bacterial cell can alter their permeability?

A
  1. Lose porins (no porins, drug can’t get in)
  2. Reduce porin channel size (hole is too smale, drug can’t get in)
  3. Decreased expression of porin (there would be fewer porins at the cell membrane)
171
Q

What is the function of porin protein channels in the outer membrane of gram-negative bacteria?

A

Bacteria can alter these protein channels to block the entry of antibiotics into their cell

172
Q

What two examples of bacteria have become resistant by altering their penicillin-binding proteins?

A
  1. MRSA

2. Streptococcus pneumoniae

173
Q

What is the function of an efflux (drug) pump?

A

Cell membrane proteins that can actively tranport drugs out of the bacteria

174
Q

What are 4 examples of bacteria that have created efllux pumps?

A
  1. Staphylococcus
  2. Streptocuccus
  3. Psudomonas
  4. E. coli
175
Q

True or False:

Efflux pumps only work on one type of drug at a time

A

False

- there is one type of efflux pump that can expel a broad varieties of antibiotics (multi-drug resistance)

176
Q

How do bacteria create antibiotic resistance with alternative metabolic pathways?

A

Bypass the action of the antibiotic

- if the drug has blocked the USUAL metabolic pathway, the microbe create an alternative metabolic pathway

177
Q

What are the two ways that microbes can acquire antibiotic resistance through the acquired or genetic way?

A
  1. Mutation

2. Genetic exchange

178
Q

What are the 3 ways that genetic exchange can occur (to develop antibiotic resistance)?

A
  1. Conjugation
  2. Transformation
  3. Transduction
179
Q

How can a bacterial microbe acquire antibiotic resistance intrinsically (or naturally)?

A

By lacking target sites or metabolic processes

180
Q

What happens if an antibiotic only kills some of the bacteria?

A

Creates stronger and more resistant bacteria

- only the weaker bacteria are killed

181
Q

What is conjugation?

A

Transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells.

182
Q

What is transformation?

A

Transfer of drug-resistant genes from a lysed donor bacterium to a genetically closely related recipient

183
Q

What is transduction?

A

Transfer of donor DNA through a (transducing) phage into the recipient bacterium
- foreign DNA is inserted through a virus

184
Q

What is horizontal transfer?

A

Genetic mechanisms to acquire and spread drug-resistance

185
Q

What is vertical transfer?

A

Passage of antibiotic-resistance genes during replication

- from one generation to the next

186
Q

What are some intrinsic factors that contribute to the emergence and spread of AROs (antibiotic resistant organisms)?

A
  • Natural selection
  • Biofilm formation
  • Horizontal transfer
  • Vertical transfer
187
Q

What are some extrinsic factors that contribute to the emergence and spread of AROs?

A
  • Overuse and misuse of antibiotics (non-compliance)
  • using antibiotics for viral infections
  • using antibiotics in animal feeds
188
Q

Why is it risky to put patients on antibiotics for a long period of time?

A

Higher chance that you kill off healthy bacteria too (good bacteria)

189
Q

What does that use of broad spectrum antibiotics put clients at risk for?

A

Lowers patient’s natural defenses against certain infections

190
Q

What is the clinical significance of rising antibiotic-resistance on patients?

A
  • ineffective therapy and unfavorable disease outcomes
  • increase morbidity
  • longer stays in hospitals
  • increase mortality
191
Q

What is the clinical significance of rising AROs on hospital practice?

A
  • additional workload for HCWs
  • infection control precautions
  • lab technologists = testing for AROs
  • extra demands on resources (isolation rooms, dedicated equipment, expensive drugs)
192
Q

What are CREs?

A

Carbapenem-Resistant Enterobacteriaceae

193
Q

What are enterobacteriaceae (EB)?

A

Large family of gram-negative facultative anaerobicbacilli

ex. E. coli

194
Q

What are carbapenems?

A

Beta-lactam drugs used to treat multi-drug resistant (extended spectrum beta lactamases/ESBLs) infections

195
Q

What do enterobacteriaceae commonly cause?

A

HAIs such as UTIs

196
Q

What is the mechanism of antibiotic resistance for CREs?

A

Produce enzymes carbapenemases to inactivate the drugs

197
Q

What are the two treatment options for CREs?

A
  1. Colistin

2. Combination therapy including aminoglycosides

198
Q

What is the most common mechanism of transmission for CREs?

A

Contact

- both direct and indirect

199
Q

What 4 areas need targeting for prevention and control of antibiotic resistant organisms?

A
  1. Reduce antibiotic selection pressures
  2. Prevent spread of AROs introduced from outside health care facility (HCF)
  3. Decrease spread of AROs in HCF
  4. Decrease genetic mutation and/or antibiotic resistance gene transfers by reducing bacterial burdens
200
Q

What are the two ways to decrease genetic mutations or gene transfers by reducing the bacterial burden?

A
  1. Use appropriate antibiotic prophylatic and decontamination
  2. Decrease microorganism concentrations (ex. drain abscesses)
201
Q

What are 4 basic steps that can be taken to prevent antimicrobial resistance?

A
  1. Prevent transmission
  2. Use antimicrobials wisely
  3. Diagnose and treat effectively
  4. Prevent infections
202
Q

What is the purpose of the Flagella in bacteria?

A

Provides motility

203
Q

What is the basal body of the flagella similar to?

A

Type 3 secretions systems (T3SS) in some gram-negative bacteria

204
Q

What is a T3SS (Type 3 secretions systems)?

A

“Molecular syringe”

- to allow bacteria to infect cells and inject certain toxins

205
Q

What is the function of fimbriae?

A

Adherence/adhesion

- helps to provide attachment to susceptible host cells and each other

206
Q

What contributes to colonization and biofilm formation?

207
Q

What are the 3 functions of pili?

A
  1. Attachment to host cells
  2. Motility
  3. Conjugation (“sex pili” - allow transfer of bacterial DNA from a host to a donor bacterium)
208
Q

What are the two types of glycocalyx?

What is it?

A

Adhesive polysaccharide substance found in some bacteria

  1. Capsules
  2. Slime layer
209
Q

Which of the two types of glycocalyx provides a more even (uniform distribution) of carbohydrates around the bacterial cell?

A

Capsule

- not slime layer

210
Q

What is the function of the glycocalyx?

A
  • Retains moisture

- Helps to survive the host’s defenses (resists capture by phagocytes)

211
Q

What are biofilms?

A

Layers of microbes largely made up of bacteria (with glycocalyx) formed on living and non-living surfaces

212
Q

What three things can biofilms do?

A
  1. Attach to host cells/non-living surfaces
  2. Makes cleaning, disinfection and sterilization difficult
  3. Acts a protective barriers - difficult for chemical biocides to penetrate
213
Q

In what bacteria are cell walls found?

A

In all bacteria except: mycoplasma (STIs, pneumonia, skin infections and cancers)

214
Q

What is the function of the cell wall?

A

Surround the bacterial cell membrane

- give shape and structure

215
Q

Cell walls are made up of multiples layers of which two types of carbohydrates?

A
  1. N-acetyl muramic (M/NAM) acid
  2. N-acetyl glucosamine (G/NAG)
    - joined together by 4 amino acids
216
Q

True or False:

Gram-negative bacteria have a cell wall

217
Q

What do cell walls contain?

A
  • porins

- lipopolysaccharides (LPS) - contains Lipid A

218
Q

What happens when a bacterial cell wall is damaged?

A
  1. Large amounts of Lipid A and tumor necrosis factor are released into the body
  2. Stimulates over-production of cytokines
  3. Results in fever and systemic inflammation
  4. Ends in ENDOTOXIC SHOCK SYNDROME
219
Q

True or False:

O-antigen is part of the LPS. Antibodies can be raised in animals against them and then use them in serotyping in labs

A

True

- I didn’t know a good question to write for this one …

220
Q

What kind of bacteria have atypical cell walls?

A

Mycobacterium and Nocardia

221
Q

What are the characteristics of atypcial cell walls?

A
  • high concentrations of unique types of lipids

- resistance to chemical biocides, dehydration, and host defenses

222
Q

What does the cell membrane consist of?

A

Phospholipid bi-layer

223
Q

What is the function of the cell membrane?

A

Highly selective barrier

  • allows for passage of nutrients and metabolic wastes
  • it is an important site for certain metabolic activities
224
Q

In Mycoplasma, what does the cell membrane contain a lot of and what does it do?

A

Large quantities of sterols - rigid lipids that gives the bacteria cell shape and integrity

225
Q

What do chromosomes contain?

A

All essential genetic information

226
Q

How many chromosomes do bacteria have?

A

1

- yup, just one

227
Q

What is inside the nucleoid or nuclear region of the bacterial cell?

A

Highest concentration of bacterial chromosomal DNA is localized

228
Q

What are plasmids?

A

Short, circular, double-stranded DNA molecules found in some bacteria

  • not part of the chromosome
  • it is extra chromosomal DNA
229
Q

If a bacteria has plasmids, what % of total DNA is contained in those plasmids?

230
Q

What do plamsids code for (2)?

A
  • antibiotic resistance

- toxin production

231
Q

How can plasmids be passed on from bacteria to bacteria?

A

Through conjugation

232
Q

How do we use plasmids to our benefit?

A

Used in recombinant DNA technology

  • producing drugs
  • producing vaccines
233
Q

What is the dormant state of a bacteria?

234
Q

What do endospores help bacteria to do?

A

Survive unfavourable conditions by sporulation

235
Q

What are examples of conditions that an endospore could survive in?

A
  • extreme high temp
  • too acidic or alkaline
  • lack of water/nutrients
  • inappropriate gaseous environment (oxygen or no oxygen)
236
Q

What are the 3 survival mechanisms of endospores?

A
  1. Thick spore coat
  2. Large amount of dipicolinic acid-calcium complexes
  3. Metabolically inactive
237
Q

What is the benefit of the thick spore coat to the endospore?

A

Physical barrier

- difficult for chemical compounds to penetrate

238
Q

What is the benefit of the large amount of dipicolinic acid-calcium complexes to the endospore?

A

Stablizies proteins to prevent their denaturation at high temp

239
Q

What is the benefit of the being metabolically inactive to the endospore?

A

Does not require foods or much energy

240
Q

What are 3 examples of sporeforming bacteria: Clostridium?

A
  1. C. difficile
  2. C. tetani
  3. C. botulinum
241
Q

What does botulism do to the body?

A

Flaccid paralysis

- numbness

242
Q

What does tetanus do to the body?

A

Spastic paralysis

- muscles fail to relax

243
Q

What are 2 examples of sporeforming bacteria: Bacillus?

A
  1. B. anthracis (anthrax)

2. C. cereus (food poisoning)

244
Q

Define infection

A

Entry and development/multiplication of an infectous agent in the body of a living object

245
Q

What are the two types of infections?

A
  1. Asymptomatic

2. Symptomatic

246
Q

What is IN VITRO intoxication?

A

Exposure to bacterial toxins outside the body

- ex: ingestion of toxins in food

247
Q

What is IN VIVO intoxication?

A

Bacteria produce toxins INSIDE the body

248
Q

What is the rationale behind vaccinations (2)?

A
  1. Stimulates the immune system to create long-lasting protective immunity
  2. Creates high-level of herd immunity to prevent transmission of the infection in a community
249
Q

Why is it important to obtain herd immunity?

A

Protects those people who cannot receive vaccinations (they are immune suppressed)

250
Q

Why do some people choose not to receive vaccinations?

A
  • personal/religious/cultural beliefs
  • concerns about vaccine safety
  • complacency (“disease is rare - therefore, it’s not needed”)
  • mistrust of government, health agencies
251
Q

Define herd immunity

A

The protection a mostly vaccinated population givers to unvaccinated groups
- protection weakens as the vaccination rate falls

252
Q

What is pertussis also known as? What is the causative agent?

A

Whooping cough

- Bordetella pertussis

253
Q

What is the mode of transmission for pertussis?

A

Direct Contact (droplet)

254
Q

True or False:

Pertussis is a gram-positive aerobic bacilli

A

False

It is a GRAM-NEGATIVE aerobic bacilli

255
Q

How is the pertussis vaccine different than a regular vaccine?

A

Acellular pertussis vaccine - does not contain a whole cell but only components of the bacteria

256
Q

What are the risk factors for pertussis?

A
  • living in same house
  • unvaccinated person
  • children not fully vaccinated ( < 6 months)
  • Immunity can wear off in adults
  • immunocompromised
257
Q

What are the 3 stages of pertussis?

A
  1. Catarrhal stage (1-2 weeks)
  2. Paroxysmal stage (1-6 weeks)
  3. Convalescent stage (2-3 weeks)
258
Q

What are the clinical features and complications of pertussis?

A
  • apnea
  • pneumonia
  • convulsions
  • encephalopathy
  • death
259
Q

What is the causative agent of diphtheria?

A

Corynebacterium diphtheriae

260
Q

True or False:

Diphtheria is a gram-positive aerobic bacilli

261
Q

True or False:

Diphtheria bacteria can enter through any mucus membrane

262
Q

What are the S/S of Diphtheria?

A
  • white, greyish-white or bluish-white pseudo-membrane on the infected site
  • maliase
  • low grade fever
  • cough
  • sore throat
  • BULL neck appearance
263
Q

What will happen if you don’t treat Diphtheria?

A

Death within 6 - 10 days

264
Q

What is the major virulence factor of Diphtheria?

A

Diphtheria toxin inhibits protein synthesis causing host cell death

265
Q

Where is the Diphtheria toxin absorbed?

A

Bloodstream

266
Q

What is the pseudo-membrane of Diphtheria made up of?

A
  • Coagulated fibrin
  • WBCs
  • Dead cells
  • Bacteria
267
Q

What are the complications of Diphtheria?

A
  • airway obstruction
  • damage to the heart (myocarditis)
  • nerve damage
  • paralysis
  • lung infection
  • death
268
Q

What are the risk factors of Diphtheria?

A
  • lack of vaccination
  • waning immunity
  • overcrowded/unsanitary living conditions
  • immunocompromised
269
Q

What kind of vaccine is the Diphtheria vaccine?

A

Toxoid (modified toxin) vaccine

270
Q

What happens if a person is admitted to the hospital with Diphtheria?

A

Person does not have time to make antitoxins

- therefore they are directly given antitoxins

271
Q

What is the causative agent of tetanus?

A

Clostridium tetani

272
Q

True or False:

Tetanus is a GRAM-NEGATIVE obligate anaerobic sporeforming bacilli

A

False

- it is a gram POSITIVE obligate anaerobic sporeforming bacilli

273
Q

What is the reservoir of tetanus?

A

Soil, contaminated fomites, and intestinal tracts of humans and animals

274
Q

What is the mode of transmission for tetanus?

A

Through broken skin (puncture, injection or bite wounds)

275
Q

What is the IP of tetanus?

A

It depends on the site of injury

- closer to the brain, faster the IP

276
Q

What is the pathogensis of tetanus?

A
  1. Infection of the wound by spores
  2. Germination of spores into bacilli
  3. Bacilli produce toxins
  4. Toxins affect CNS
277
Q

What are the clinical features of tetanus?

A
  • mild spasms
  • lock jaw
  • problems with swallowing
  • back spasms
  • pulmonary embolism
  • pneumonia
  • death
278
Q

What are the risk factors for generalized tetanus?

A
  • unvaccinated
  • injected street drugs
  • occupational exposure
279
Q

What kind of vaccine is the tetanus vaccine?

A

Toxoid vaccine

280
Q

What does the DTaP protect against?

A

Diphtheria
Tetanus
Pertussis

281
Q

What is the medical management for a tetanus?

A
  1. Clean the wound
  2. Keep wound aerated
  3. Remove any foreign objects
  4. Remove necrotic tissue
282
Q

What is the causative agent of Pneumococcal disease?

A

Streptococcus penumoniae

283
Q

What kind of bacteria are streptococcus pneumoniae?

A

Gram-positive cocci, most are facultative anaerobes and encapsulated

284
Q

What happens in invasive pneumococcal disease (meningitis)?

A

When bacteria invade parts of the body that are normally sterile

285
Q

When does the POC stop in meningitis?

A

Within 24 hours of antibiotic therapy

286
Q

What are the S/S of meningitis?

A
  • fever
  • severe headache
  • poor eating
  • vomiting
  • drowsiness
  • STIFF NECK
287
Q

What are the complications of meningitis?

A
  • Hearing loss
  • Developmental delay
  • Death
288
Q

What are the two major types of pneumococcal vaccines?

A
  1. Pneumococcal conjugate vaccine (PCV)

2. Pneumococcal polysaccharide vaccine (PPV)

289
Q

How id PCV different than PPV?

A 
PCV = old vaccine, protects against 13 strains
PPV = new vaccine, protects against 23 strains
290
Q

What is another form of pneumococcal are the elderly and immuno-compromised people at a higher risk of contracting?

A

Pneumococcal Pneumonia

291
Q

What kind of bacteria are hemophilus influenzae b (Hib)

A

Gram negative coccobacilli, aerobic, encapsulated serotypes

292
Q

What are the S/S of Invasive Hib (Meningitis)?

A
  • Fever
  • Headache
  • N/V
  • Confusion
  • STIFF NECK
  • increased sensitivity to light
293
Q

What is the IPV vaccine for?

294
Q

What does the Hib vaccine contain?

A

Capsular polysaccharide

- not whole cell vaccine

295
Q

What is IMD?

A

Invasive meningococcal disease

296
Q

How many serotypes of IMD are there? What are they?

A 
A
B
C
X
Y
W-135
297
Q

In what disease do the invasion of the bacteria cause reddish or purple skin rash?

A

Meningococcal septicemia/bacteremia

NURS 2228 - Microbiology (9 decks)

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