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Microbiology > Lec 21: Respiratory Infections > Flashcards

Lec 21: Respiratory Infections Flashcards

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1
Q

what is the #1 major portal of entry?

A

the respiratory tract

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2
Q

what is the transmission for the respiratory tract?

A
  1. Droplets
  2. Contact- ex: hands to eyes, nose, or mouth
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3
Q

how are droplets transmitted within the respiratory tract?

A

The droplets are formed during coughing and sneezing.
If the droplets are:
-Smaller than 5 um, they can travel more than 6 ft and are airborne.
-Bigger than 5 um, they can travel 3-6 ft

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4
Q

what is the abbreviation for upper respiratory tract?

A

URT

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5
Q

what does the suffix “itis” mean?

A

inflammation

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6
Q

within the upper respiratory tract, there are the following inflammation/infections. what part of the URT does it affect?
-Rhinitis
-Sinusitis
-Pharyngitis
-Ottis media

A

-Rhinitis: inflammation of the nose
-Sinusitis: inflammation of the sinuses (cavities in the bones around the nose)
-Pharyngitis: inflammation of the pharynx (throat)
-Ottis media: inflammation of the middle ear

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7
Q

what is the Eustachian tube?

A

the tube that connects the throat to the middle ear

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8
Q

within the lower respiratory tract, there are the following inflammation/infections. what part of the LRT does it affect?
-Laryngitis
-Tracheitis
-Bronchitis
-Bronchiolitis

A

-Laryngitis: inflammation of the larynx (voice box)
-Tracheitis: inflammation of the trachea (windpipe)
-Bronchitis: inflammation of the bronchi (the two large airways)
-Bronchiolitis: inflammation of the bronchioles (small airways)

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9
Q

what are alveoli? are they thick or thin and why?

A

When the smallest bronchioles balloon out into clusters of air sacs that are called alveoli.
They are 1 cell thick (so they are very thin) to allow air exchange between lungs and blood vessels.

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10
Q

what is pneumonitis?

A

-Pneumonitis is inflammation of all of the alveoli leading to inflammation of the whole lung.
-This happens when fluid and cells from the blood vessels accumulate in and around the air sacs, making gas exchange difficult.

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11
Q

what is pneumonia?

A

lung inflammation and infection

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12
Q

what is the difference between pneumonitis and pneumonia?

A

Pneumonitis is just inflammation of the alveoli and whole lung.
Pneumonia is when the inflammation is DUE to infection.

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13
Q

list defense mechanisms of the respiratory tract

A

-Flushing actions including sneezing, coughing, and mucociliary escalator.
-Normal microbiota in the nose and throat.
-Alveolar macrophages

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14
Q

in the defense mechanisms of the respiratory tract, there are flushing actions. what do they include?

A

-Sneezing and coughing
-Mucociliary escalator: when mucus traps pathogens, and the cilia beat upwards to expel the mucus from the throat and into the stomach.
If the mucus is too thick, then an infection is more likely to occur.

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15
Q

what type of microbiota works as a defense mechanism in the respiratory tract?

A

normal microbiota in the nose and throat

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16
Q

how do alveolar macrophages work as defense mechanisms within the respiratory tract?

A

they are constantly scouting for pathogens, engulfing them, and getting rid of them

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17
Q

what are examples of 2 upper respiratory infections?

A

Streptococcal pharyngitis (strep throat)
Common cold

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18
Q

what is the etiology of Streptococcal pharyngitis?

A

-It is caused by Group A Streptococcus pyogenes (GAS)
-It is Gram-positive cocci in chains that causes strep.
-It is Beta-hemolytic, so there is a complete lysis of RBCs.

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19
Q

what is the epidemiology of Streptococcal pharyngitis?

A

-Seasonal, so more common in winter.
-There are asymptomatic carriers that are healthy because of their healthy gut microbiome. But they can still transfer it

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20
Q

what is Streptococcal pharyngitis (Strep Throat) pathogenesis?

A

Pharyngitis: the inflammation of the pharynx with possible systemic complications caused by toxins or antibodies

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21
Q

what are the symptoms of strep throat?

A

Sore throat, pus (white streaks at the back of the throat), redness, fever, enlarged lymph nodes in neck area

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22
Q

what is the treatment for strep throat?

A

antibotics

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23
Q

what is the prevention for ALL RESPIRATORY ILLNESSES?

A

-Hand washing
-Avoid touching face
-Cover sneezes and coughing
-Masks
-Social distancing

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24
Q

can strep throat cause complications? what types?

A

yes, localized and systemic

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25
Q

what is the localized strep throat complication?

A

The Strep throat infection destroys the cilia on cells in the sinus ducts and auditory tube, so the bacteria can track up there and cause:
-Sinusitis
and
-Otitis media

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26
Q

what are all the systemic strep throat complications?

A

-Scarlet fever
-Glomerulonephritis
-Rheumatic fever
-PANS

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27
Q

what happens with scarlet fever - the systemic complication from strep?

A

Caused by SPE (Streptococcal Pyrogenic Exotoxin)-producing strains.
Causes high fever, skin roughening, and a red rash

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28
Q

what happens with Glomerulonephritis - the systemic complication from strep?

A

It is a type 3 hypersensitivity

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29
Q

what happens with PANS - the systemic complication from strep?

A

the Abs enter the brain by crossing the blood-brain barrier

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30
Q

what happens with rheumatic fever - the systemic complication from strep?

A

type 2 hypersenstivity

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31
Q

what is the etiology (cause) of the common cold?

A

It is caused by more than 100 types of rhinoviruses (up to 50%).
This includes other viruses like coronaviruses (NOT SARS-CoV-2) and RSV.

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32
Q

what is the epidemiology of the common cold?

A

It is season, and more common in winter

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33
Q

what is the pathogenesis of the common cold?

A

It is when infected URT cells die and there are no cilia. This causes the cells to lyse and die. This can cause complications, like sinusitis and middle ear infection.

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34
Q

what are the symptoms of the common cold?

A

Nasal congestion, sore throat, and cough

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35
Q

what is the treatment for the common cold?

A

-Self-limiting within 1 week
-OTC drugs like decongestants treat symptoms ONLY
-Drink fluid to prevent dehydration from sneezing
-Use a humidifier and rinse sinuses to prevent thick dehydrated mucus from plugging up the sinus and auditory ducts.

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36
Q

can you actually treat a common cold?

A

No, it will last 1 week either way.
You can treat the symptoms, but not the actual virus

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37
Q

what is the prevention for the common cold?

A

same thing for all respiratory infections

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38
Q

what can be a complication of the common cold?

A

Secondary bacterial infections, especially sinusitis and otitis media, can be a complication of the common cold.

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39
Q

what happens with otitis media after the common cold?

A

The common cold is a primary infection that can cause secondary bacterial infections like Otitis media.
Otitis media is common in children under the age of 5 due to their ear anatomy. The tube is short and straight, preventing the draining of pus into the pharynx, which causes the pus to get trapped behind the ear drum causing pain. Then you have to take antibiotics.

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40
Q

Otitis media and sinusitis are secondary bacterial infections that can occur after a primary infection with:
1. Common cold
2. Strep throat
3. Both 1 and 2
4. Neither 1 or 2

A
  1. Both 1 and 2
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41
Q

even though the common cold is NOT an infection and it IS a virus, can the secondary infection be a bacterial infection?

A

yes!

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42
Q

what are 3 examples of lower respiratory infections?

A

Pneumonia
TB
Flu

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43
Q

what is the etiology of pneumonia?

A

it is caused by MANY different microbes, including:
-Streptococcus pneumonia (Gram-positive coccus): pneumococcal pneumonia - which is the most common cause.
-Mycoplasma pneumonia (wall-less bacterium): walking pneumonia
-Many other bacteria
-Viruses (ex: Flu, RSV, SARS-CoV-2)
-Fungi (ex: valley fever, aspergillosis)

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44
Q

what is the most common cause of pneumonia (etiology-wise)?

A

Streptococcus pneumoniae - pneumococcal pneumonia

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45
Q

does pneumonia usually affect healthy people?

A

No

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46
Q

what is the epidemiology of pneumonia?

A

Pneumonia is caused by inflammation of all alveoli due to infection.
-It is a disease of the immunocompromised due to:
a. age (often young or old)
b. smokers
c. immunodeficient people (ex: ppl with AIDS)
d. complications after influenza or other illnesses
e. poverty
c. stress

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47
Q

are there asymptomatic carriers of pneumonia?

A

yes, there are asymptomatic carriers of S. pneumoniae

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48
Q

what is the pathogenesis of pneumonia?

A

-The bacteria is often encapsulated, so it resists phagocytosis
-Induces inflammation: fluid, inflammatory cells in alveoli, impedes gas exchange which leads to shortness of breath

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49
Q

what is the diagnosis of pneumonia?

A

Chest X-ray
(pneumonia patient is seen with an accumulation of fluids seen as white and you cannot see the heart)

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50
Q

what are symptoms of pneumonia?

A

Cough (with or without bloody sputum), shortness of breath, fever, and chest pain

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51
Q

what is the treatment of pneumonia?

A

Antibiotics.
However, there is increasing resistance to antibiotics seen with S. pneumoniae

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52
Q

what is the prevention for pneumonia like?

A

-Polysaccharide vaccine for pneumococcal pneumonia (Prevnar): given to children under 5 years and older people over 65
-Flu vaccine
-All the regular prevention

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53
Q

what are the possible complications of pneumonia?

A

-permanent lung damage if left untreated
-bacteremia: infection can spread to other organs (from lungs)
-meningitis
-can lead to death

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54
Q

what is the etiology of tuberculosis?

A

Mycobacterium tuberculosis
-Acid-fast rod
-Mycolic acid: waxy lipids in the cell wall that allow them to survive within phagocytes
-Slow growth (the doubling time is around 24 hrs)

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55
Q

how much of the world is estimated to be infected with tuberculosis?

A

1/3rd of the world

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56
Q

what is the epidemiology of tuberculosis?

A

Latent or Active TB

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57
Q

what is latent TB?

A

-When the pathogen goes in hiding, and there is no active infection.
-no spread
-Chest X-ray is normal
-Still have to take drugs to target any bacteria that get reactivated

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58
Q

what is active TB?

A

Active, or reactivated TB:
-Active infection with symptoms
-It can spread
-Chest X-ray shows lung damage
-Drugs target actively dividing bacteria - easier to treat active infection

59
Q

Active TB is seen with what patients?

A

Active TB is seen with immunocompromised, esp patients with AIDS

60
Q

are there resistant forms of TB? what are the two types of resistant TB?

A

Yes, resistant forms are on the rise. There are
-Multiple drug-resistant TB (MDR-TB)
-Extensively drug-resistant TB (XDR-TB)

61
Q

is TB airborne?

A

yes

62
Q

how is tuberculosis transmitted?

A

-Bacteria cells become airborne when an infected person talks, coughs, sneezes, etc.
-People nearby become infected when they breathe in the contained air.

63
Q

what are the steps of the pathogenesis of TB?

A
  1. Cells enter the lungs, where alveolar macrophages engulf them.
  2. Mycobacteria survive in macrophages.
  3. Granuloma or tubercle formation:
    a. The immune system does this to prevent the spread of bacteria.
    b. In latent TB, bacteria stay dormant in tubercles.
64
Q

what two things do the steps of pathogenesis of TB cause?

A
  1. Caseous necrosis:
    -In active TB, bacteria divide and destroy macrophages to form “cheese-like” (caseous) pus containing dead cells (necrosis)/
  2. Cavitations:
    -Tubercles burst to release pus and bacteria into bronchioles, which are coughed up to your throat.
    -Empty tubercles form cavities (cavitations).
65
Q

what happens if cavitation does not heal?

A

it leads to decline in lung function

66
Q

what are the symptoms of TB?

A

Coughing blood sputum, fever, night sweats, tissues waste away (consumption)

67
Q

what are 4 diagnoses for TB?

A

-Tuberculin skin test
-QuantiFERON
-Radiograph
-Sputum test

68
Q

what is the Tuberculin skin test?

A

It is a Tuberculin Purified Protein Derivative (PPD) injection
-It is a type 4 hypersensitivity
-You can have a false positive if you are vaccinated

69
Q

what is the QuantiFERON test?

A

-Detects cytokine released by the sensitized T cells
-No false positives if you are vaccinated
-Cannot distinguish active vs. latent

70
Q

what does the Radiograph test for TB show?

A

if you have an active infection, cavitations are seen

71
Q

what does the sputum test for TB show?

A

If you have an active infection, you see rod-shaped bacteria.
it is an acid-fast staining

72
Q

what is the down side of the Tuberculin skin test? what is the next best thing?

A

With the Tuberculin skin test, you can test falsely positive if you are vaccinated.
So the next best thing is the QuantiFERON test, which has no false positives if you are vaccinated.

73
Q

what is the downside of the QuantiFERON test? what is the next best thing?

A

With the QuantiFERON test, you cannot distinguish between active and latent TB infections.
The next best thing would be to do a Radiograph or X-ray, which detects active infections though cavitations.
You can also do the Sputum test, which shows an active infection through rod-shaped bacteria.

74
Q

what are the 3 types of resistant TB?

A
  1. MDR-TB
  2. XDR-TB
  3. TDR-TB
75
Q

what is the first treatment like for TB? how long should treatment be given?

A

combination therapy with first-line drugs (ex: isoniazid and rifampin) for at least 6 months, since they are slow replicators

76
Q

what is MDR-TB?

A

Multiple drug-resistant TB, so it is TB that requires longer treatment with second-line drugs. This is less effective and more toxic than first-line drugs.

77
Q

what is XDR-TB?

A

Extensive drug-resistant TB, so it is TB that is even harder to treat. You need more drugs that treat even more resistant TB. Tests guide therapy.

78
Q

what is TDR-TB?

A

Total drug resistance, which is really resistant to drugs.

79
Q

what is DOT?

A

directly observed therapy, where you watch the TB + patient to make sure they are taking their drugs everyday.

80
Q

are there newer drugs in development for TB?

A

yes

81
Q

what are two preventions of TB?

A

-BCG vaccine, which is the cow version of TB. It is not used in the US
-Improve living standards

82
Q

is the BCG vaccine used in the US?

A

no

83
Q

what are 3 possible complications of TB?

A

-Permanent lung damage
-Bacteremia can lead to infection of other organs, ex: pott disease
-Death

84
Q

what is the etiology of influenza?

A

Influenza is caused by 4 types of influenza viruses: A, B, C, and D.

85
Q

what influenza virus causes the seasonal flu?

A

Type A or B

86
Q

what influenza virus causes a pandemic flu?

A

Type A

87
Q

what type of influenza virus do we discuss in class?

A

type A only

88
Q

what is the host range like for influenza?

A

cattle, birds, pigs, horses, seals, humans, etc.

89
Q

is influenza A virus enveloped or non-enveloped?

A

lipid enveloped

90
Q

does influenza A have RNA or DNA? how about segments?

A

Influenza A has RNA with 8 segments/pieces of RNA molecules.

91
Q

what are the two types of spike proteins/Ags that are located on influenza A viruses?

A
  1. Hemagglutinin Ag (H)
  2. Neuraminidase Ag (N)
92
Q

what is Hemagglutinin Ag (H)?

A

It is used to attach to host receptors.
There are 18 subtypes - H1 through H18

93
Q

what is Neuraminidase Ag (N)?

A

It is used for release. There are 11 subtypes - N1 through N11

94
Q

how many possible strains are there of influenza type A?

A

144

95
Q

which two strains of influenza A are currently circulating?

A

H1N1 and H3N2

96
Q

what was influenza’s original reservoir?

A

originally in wild aquatic birds

97
Q

what does influenza spread through?

A

it spreads through respiratory secretions/feces

98
Q

can influenza spill over? where?

A

yes, it can spillover in domesticated birds, pigs, and then humans

99
Q

what is antigenic drift in influenza?

A

-Small mutations due to changes in spike proteins
-Can cause the seasonal flu
-This is the reason why we get the flu shot each season, because the flu keeps mutating
-There is crossover immunity
-Low death rate

100
Q

what is antigenic shift in influenza?

A

-Large mutations
-Can cause severe pandemic outbreak flu’s
-No crossover immunity
-High death rate
-Coinfection
-Reassortment

101
Q

what are the two reasons for the large mutations/changes in antigenic shifts in influenza?

A

Coinfection and Reassortment

102
Q

what is coinfection?

A

It is an infection with two or more different viruses at the same time.
So there are RNA segments from 2 different viruses coming together

103
Q

what is reassortment?

A

The mixing and repackaging of those genome segments from two or more viruses.

104
Q

why are coinfection and reassortment so dangerous?

A

because it causes a mix of viruses that we have no immunity to - so it can cause a pandemic

105
Q

what is an example of a pandemic outbreak caused by an influenza antigenic shift?

A

the 2009 swine flu

106
Q

what is an example of reassortment?

A

pig that is coinfected with a bird and human viruses

107
Q

what is influenza triple reassortment?

A

When the host gets infected by 3 different viruses.
It is when the resulting virus has RNA segments from all 3 viruses.

108
Q

what is an example of triple reassortment?

A

When a pig is infected with:
1. Pig virus
2. Bird virus
3. Human virus
(all at the same time)

109
Q

what is influenza quadruple reassortment?

A

When the host is infected with 4 different viruses.
It is when the resulting virus has RNA segments from all 4 viruses.

110
Q

what is an example of a quadruple reassortment? what is an example of a disease that it caused?

A

When a pig is infected with:
1. Eurasian pig virus
The virus is formed from a reassortment of:
2. Classic pig virus
3. Human virus
4. Bird virus
(all at the same time)
An example of a quadruple reassortment disease is when it caused the 2009 swine flu

111
Q

what is the pathogenesis of infleunza? what does it infect?

A

It infects the upper and lower respiratory tract, those cells die, and there are no cilia

112
Q

what are the symptoms of influenza?

A

Fever, body aches, cough, sneezing, sore throat

113
Q

what are the differences between the common cold and influenza?

A

Influenza is ALWAYS accompanied by fever and body aches, whereas the common cold does NOT have those 2 symptoms.

114
Q

what is the treatment for influenza?

A

-Usually self-limiting within 1 week
-Anti-viral medications (Neuraminidase inhibitors”Oseltamivir (Tamiflu) and zanamivir (Relenza)

115
Q

why is it so difficult to make flu vaccines?

A

Because there are so many different types of the flu and the spikes keep mutating

116
Q

what do labs around the world survey regarding the flu?

A

labs around the world survey circulating flu strains in birds and people

117
Q

what are two different vaccines for influenza?

A

-Inactivated: can get it if you are more than 6 months of age. This is the shot we take every year.
-Attenuated intranasal (FluMist): 2-49 years

118
Q

why are inactivated flu vaccines given every year?

A

Because of all the spike mutations

119
Q

what do they make the vaccine based on?

A

they base making the vaccine on 3 strains predicted by surveying circulating strains in birds/humans.
This takes 6-9 months to create

120
Q

how long does it take to make a flu vaccine?

A

6-9 months

121
Q

is the flu vaccine always effective?

A

no, the flu vaccine effectiveness varies, so it is not always accurate

122
Q

what is the percentage of effectiveness of flu vaccines?

A

40-60% effective in prevention in a good year (but can reduce severity)
-Variability of immune response
-Accuracy of prediction

123
Q

what are the possible complications of influenza?

A

-Secondary bacterial infections, especially pneumonia
-Deaths

124
Q

what is the location of the cold vs flu?

A

Cold: URT
Flu: LRT

125
Q

what are the etiology differences between cold vs. flu?

A

Cold and flu both are caused by different viruses

126
Q

what are the complication differences between cold and flu?

A

some different complications

127
Q

what is prevention of cold and flu?

A

Vaccine only for flu

128
Q

what is the treatment of cold and flu?

A

Anti-virals may be used for flu only

129
Q

when should you say yes vs no to antibiotics?

A

-Say YES to antibiotics when needed for certain infections caused by bacteria.
-Say NO to antibiotics for viruses, such as colds and flu, or runny noses, even if the mucus is thick, yellow, or green

130
Q

which of the following does NOT have a vaccine for prevention?
1. Tuberculosis
2. Influenza
3. Pneumococcal pneumonia
4. Walking pneumonia

A
  1. Walking pneumonia

explanation:
1. Tuberculosis (VCG)
2. Influenza (inactivated and attenuated)
3. Pneumococcal pneumonia (fraction of vaccine - capsule)

131
Q

can viruses, bacteria, and fungi all cause pneumonia?

A

yes

132
Q

Which of the following pairs is mismatched?
1. Mycoplasma pneumoniae: wall-less bacterium
2. Mycobacterium tuberculosis: acid-fast rod
3. Group A Streptococcus pyogenes: influenza A virus
4. Streptococcus pneumoniae: Gram-positive coccus
5. Common cold: rhinoviruses (up to 50%)

A
  1. Group A Streptococcus pyogenes: influenza A virus
133
Q

A patient presents with a sore, red throat. What is the diagnosis?
1. Strep throat
2. Common cold
3. Influenza
4. Pneumonia
5. There is insufficient information

A
  1. There is insufficient information
134
Q

Which of the following means inflammation of the middle ear?
1. Otitis media
2. Bronchitis
3. Pneumonia
4. Periodontitis
5. Cystitis

A
  1. Otitis media
135
Q

A person can have a positive tuberculin (PPD) skin test because:
1. She had the BCG vaccine
2. She has active tuberculosis
3. She had tuberculosis
4. She has latent tuberculosis
5. All of the above

A
  1. All of the above
136
Q

Which of the following is not true about the influenza vaccine?
1. It is not always a good match to the circulating strains
2. It contains three different influenza strains
3. It takes 6-9 months to create
4. It can be given as a nasal mist
5. It is a polysaccharide vaccine

A
  1. It is a polysaccharide vaccine
137
Q

Why is it so difficult to prevent influenza? How might future influenza pandemics arise?

A

The influenza virus vaccine is actually 70-90% effective against the flu. However, the virus is constantly mutating (through the mechanisms of antigenic drift and shift), and scientists must try to predict which strains are going to predominate in a particular year. The antibody generated from the last exposure may be less effective or even completely useless against the newest form.

There is a huge reservoir of influenza viruses (with many possible H and N spikes) in wild birds. Being the natural hosts for influenza, wild birds are usually unharmed when infected due to a history of co-evolution for decreased virulence. Wild birds can give influenza viruses to domestic birds and pigs. Domestic animals can then spread influenza to humans. Through co-infection and reassortment in the various hosts, influenza viruses mix up their RNA segments, creating novel viruses which may infect humans. Since there is no herd immunity to novel viruses, pandemics can easily begin. The biggest concern comes from viruses like H5N1 and H7N9, which have high mortality rates (since there is no history of co-evolution for decreased virulence). Luckily, at this point, these are only spread from domestic birds to humans by contact with feces or respiratory secretions, although limited human-to-human transmission has been reported. But it would not take much for these viruses to mutate enough to be able to be passed easily from person to person. With no herd immunity, a widespread deadly pandemic could occur, killing millions of people.

138
Q

Otitis media and sinusitis are usually preceded by a(n)
1. nasopharyngeal infection.
2. urinary tract infection
3. gastrointestinal infection.
4. middle ear infection.

A
  1. nasopharyngeal infection.
139
Q

Colds are effectively treated with
1. None of the choices is correct.
2. aspirin and acetaminophen.
3. antibiotics.
4. humidifiers

A
  1. None of the choices is correct.
140
Q

The characteristic virulence factor of S. pneumoniae is
1. pili
2. cilia
3. capsule
4. flagella

A
  1. capsule
141
Q

Antigenic shifts may be the result of
1. conjugation of two viruses.
2. blending of a bacterial and a viral genome.
3. two different viruses infecting a cell at the same time.
4. point mutations in viral genome

A
  1. two different viruses infecting a cell at the same time.
142
Q

The virulence of the tubercle bacillus is due to its
1. pili
2. resistance to antibiotics.
3. toxin.
4. survival within macrophages.

A
  1. survival within macrophages.
143
Q

How are respiratory infections transmitted?

A

Droplets (coughing and sneezing) and contact (hands to eyes, nose, or mouth).

144
Q

What are the innate immune defenses in the respiratory tract to get rid of pathogens?

A

Sneezing, coughing, mucociliary escalator, and the normal microbiota in the nose and throat.

Microbiology (53 decks)

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