25 - Bacterial Infections of the Upper Respiratory Tract II Flashcards
(138 cards)
1
Q
What is diptheria?
A
A deadly toxin-mediated disease of the upper respiratory tract
2
Q
How do we aim to control diphtheria?
A
A toxoid vaccine - that means that the vaccine is based on the toxin’s antigen
3
Q
What are the symptoms of diphtheria?
A
- Mild sore throat
- Slight fever
- High fatigue
- Malaise
- Neck swelling
- Whitish gray membrane on the tonsils, throat and nasal cavity
4
Q
What does malaise mean?
A
A feeling of general discomfort or uneasiness, of being “out of sorts”, often the first indication of an infection or other disease
5
Q
How dramatic is the neck swelling in diphtheria?
A
- Often dramatic
- Other infections may also include neck swelling, but it tends to be a bit more severe in diphtheria than it is in other infections
- We call this “bull neck appearance”
6
Q
What other clinical condition would you need to differentiate diphtheria from?
A
Strep throat
7
Q
How do we often describe the appearance of diphtheria under a light microscope?
A
Often described as appearing like chinese letters
8
Q
What is the organism that causes diphtheria?
A
Corynebacterium diphtheriae
9
Q
What type of bacteria is Corynebacterium diphtheriae?
A
- Variable shape
- Non-motile
- Non-spore forming
- Gram positive
- Rod
10
Q
What is unique about this gram positive rod bacteria?
A
A lot of gram positive rods form spores, but this one does NOT
11
Q
What is the diphtheria exotoxin?
A
It is the MAIN virulence factor in diphtheria
12
Q
What type of exotoxin is the diphtheria exotoxin?
A
It has been lysogenized by a bacteriophage
13
Q
What does it mean that the exotoxin was lysogenized by a bacteriophage?
A
It did not have this in its genome originally – the bacteriophage brought it in
14
Q
How common is this exotoxin?
A
It is almost impossible to find a diphtheria strain that does not have the diphtheria exotoxin gene lysogenized into it – it doesn’t really happen
15
Q
Is the diphtheria toxin invasive?
A
NO
16
Q
How does the diphtheria toxin get into the body?
A
- It is passively absorbed by the bloodstream
- It sits on top of the tissue and releases toxin, which is then absorbed by the blood stream
17
Q
What is the signature feature of diphtheria?
A
A classic gray-white membrane
18
Q
What is the gray-white membrane of diphtheria made of?
A
- Clotted blood
- Epithelial cells of the mucous membrane
- Leukocyte infiltrate
19
Q
Would you see a similar gray-white membrane in patients with strep throat?
A
No - it is unique to diphtheria
20
Q
Does the gray-white membrane easily peel off the affected areas?
A
No - it is not easy to peel off (because it involves the tissue membrane) and it will contain epithelial cell from the mucous membrane
21
Q
What does the gray-white membrane cover?
A
The tonsils and uvula in a very severe case
22
Q
What are the three things you will be differentiating between?
A
- Diphtheria
- Group A strep throat
- Infectious mononucleosis
* the signature membrane will be a major clue*
23
Q
Is the diphtheria toxin released in the active or inactive form?
A
INACTIVE
24
Q
What are the two subunits of the diphtheria toxin?
A
A subunit and B subunit
25
What does the A subunit do?
Active subunit
- Enters the cell
- Inactivates elongation factor-2
- Stops protein synthesis
- Induces cell death
26
Is the A subunit a true enzyme or not?
YES - it can continue to act again and again after it undergoes one round of activity
27
What does the B subunit do?
Binding subunit
| - Binds to the host cell receptor
28
If a patient is able to survive a diphtheria infection, where would you see damage?
- Heart
- Kidneys
- Nerve cells
29
Why are these ares affected and not others?
This is where the B subunit receptors bind - what they have an affinity to
30
Is the A-B subunit structure of this bacterial toxin common or unique to diphtheria?
Common
31
How does the A-B subunit work?
There is an active portion and a binding portion that often works by ADP ribosylation
32
What is ADP ribosylation again?
The addition of one or more ADP-ribose moieties to a protein
These reactions are involved in cell signaling and the control of many cell processes, including DNA repair and apoptosis
33
What is the overall process of the A-B toxin in the case of diptheria?
Summary
- We get binding of the A portion
- It is endocytosed and cleaved
- It then inactivates the elongation factor 2
- Stops protein synthesis
- Kills the cell
34
What are the two types of conjunctivitis?
- Bacterial conjunctivitis
| - Viral conjunctivitis
35
How do you distinguish between the two types?
One way to do this is by the amount of pus that is formed (not a hard fast rule, but it is often the case)
36
Which type has more pus formation and which has less?
Bacterial = more pus, swelling tends to be more severe
Viral = less pus, swelling tends to be less severe
37
There are two MAIN causative agents of bacterial conjunctivitis. What are they?
***
1 - Haemophilus influenzae
2 - Streptococcus pneumoniae
*** NEED TO KNOW ***
38
There are three other types of bacteria that can cause bacterial conjunctivitis, but are less common. What are they?
1 - Moraxella lacunata
2 - Enterobacteria (when it gets in the eye)
3 - Neisseria gonorrhoeae
39
What is the relevance of having many causative agents?
- We are not talking about a specific disease, we are talking about a specific presentation and the group of organisms that can cause that presentation
- When you’re treating it, you need to know that
40
What does a H influenzae type B culture look like?
- Light colored, red or pink, rods
| - Hard to see and small
41
What is the first and primary goal when treating bacterial conjunctivitis?
First, you need to stop the spread, because everyone exposed can get it
42
How do you stop the spread?
1 - Removed from school or daycare settings
2 - Hand washing, not rubbing eyes, eliminating common towels
(organism doesn’t die on common surfaces)
43
How contageous is bacterial conjunctivitis?
Very...
If your child has it, you can get it… If you are a healthcare worker and a patient comes in with it, you can get it
44
How do you treat bacterial conjunctivitis?
Gentamicin or ciprofloxacin eye drops
45
What is the perk of using antibiotics topically?
We are able to avoid the resistance issues that arise when used IV or internally
46
There are other side effects associated with gentamicin. Do those effect patients when used topically?
No
47
How effective are gentamicin and ciprofloxacin in treating bacterial conjunctivitis?
They both work very well
48
What two types of bacteria have developed some strains that are resistant to local antibiotics?
1 - Haemophilus influenzae
| 2 - Streptococcus pneumoniae
49
How will you know if this is likely to present in your patients?
You will need to watch what is going on in your region...
Denver could have resistant organisms going around, but in Des Moines, we could have no issues with it
50
What are the two causative agents in both otitis media and sinusitis?
1 - Haemophilus influenzae
| 2 - Streptococcus pneumoniae
51
Are these the same or different organisms that are the main cause of conjunctivitis?
Same
52
What is the conclusion from this finding?
The conclusion would be that these organisms are all over, they spread from person to person, and we see different diseases in different tissues of the body
53
What is the main group of bacteria that demonstrate alpha hemolysis?
Strep pneumoniae
54
Which one of the two causitive agenst of otitis media and sinusitus do we have a vaccine for?
Type b haemophilus influenzae
55
What trends have we seen in type b haemophilus influenzae since the development of this vaccine?
The incidence of disease caused by type B haemophilus influenzae decreased dramatically after the introduction of the vaccine
56
What trends have we seen in NON-type b haemophilus influenzae since the development of this vaccine?
The incidence of disease caused by non-type B haemophilus influenzae did NOT change
57
Which type of haemophilus influenzae is the most deadly?
Type b
58
Are non-type b haemophilus influenzae still prevalent?
Yes, we still have a lot of non-type b infections
59
What are the three agents that can cause otitis media?
1 - Streptococcus pneumoniae
2 - Haemophilus influenzae
3 - Moraxella catarrhalis
60
What type of bacteria is strep pneumoniae?
Gram positive cocci
61
What type of bacteria is haemophilus influenzae?
Gram negative rod
62
What type of bacteria is moraxella catarrhalis?
Gram negative rod
63
What is interesting to note about these causitive agents?
SAME ORGANISMS that we see in conjunctiva - this is important ***
64
How would you describe otitis media?
Swelling, painful, pus filled tympanic membrane
65
What will happen if you've had frequent ear infections?
Scarring on the tympanic membrane
66
What are the three agents that can cause sinusitus?
1 - Streptococcus pneumoniae
2 - Haemophilus influenzae
3 - Moraxella catarrhalis
***SAME THREE AS OTITIS MEDIA***
67
What can we see forming in cases of sinusitus?
Abscess formation can occur
68
Can the agents that cause sinusitus lead to severe infections or are they mostly limited to mild infections?
They CAN cause pretty severe infections when they are allowed to - when they go untreated
69
What is beta hemolysis?
Beta hemolysis
- Demonstrates COMPLETE hemolysis
- So, complete lysis of the RBCs, so it will be CLEAR on the blood auger plate
70
What is alpha hemolysis?
Alpha hemolysis
- Demonstrates INCOMPLETE hemolysis
- So, incomplete lysis of the RBCs, so it will look green on the blood auger plate because of the red-green color spectrum
71
Does strep pneumoniae demonstrate alpha or beta hemolysis?
Alpha hemolysis
72
Which pathogen group is the MAJOR group that causes otitis media and sinusitus?
Strep pneumoniae
73
What does this mean for hamophilus influenzae and moraxella catarrhalis?
They are a bit of a "step down"
74
What vaccine will include streptococcus pneumoniae?
This is what you will see in the pneumonia vaccine (“pneumo-vax”)
75
What is the purpose of the pneumonia vaccine?
Try to prevent elderly from getting pneumonia from streptococcus pneumoniae
76
Is strep pneumonia ever part of the normal flora or is it a strict pathogen?
It is normal flora - it's all over
77
What can strep pneumonia cause, especially in immunocomprimised individuals?
- Paranasal sinusitus
- Middle ear infections (otits media)
- Lobar pneumonia
- Meningitis
78
What is one reason that we need to take strep pneumoniae seriously as a pathogen?
Can cause purulent (infectious) basilar meningitis, so we NEED to take this organism seriously
79
At the Ellis Island immigration center, what were US puplic health officials looking for?
- Cholera
- Scalp and nail fungus
- Insanity
- Mental impairments
80
What was the most common "exclusion because of disease"?
By far the most common “exclusion because of disease” cases were the result of trachoma
81
What is trachoma?
It is an infectious disease of the eye caused by the bacterium Chlamydia trachomatis
82
There are three groups in the Chlamydiaceae family. What are they?
- Chlamydia tachomatis
- Chlamydophilia psttaci
- Chlamydophilia pneumoniae
83
Two of the pathogens are chlamydophilia. What does that mean about the pathogen?
- VERY small
- Obligate intracellular parasites
(they are really pathogens, not a true parasite, but get called parasites because of they need a host to live)
84
There are two functional forms of chlamydia bacteria that exist. What are they?
1 - Elementary bodies (EB)
| 2 - Reticulate bodies (RB)
85
What are elementary bodies (EB)?
- Metabolically inactive
| - Infectious
86
What are reticulate bodies (RB)?
- Metabolically active
| - Non-infectious form
87
What diseases is the chlamydia tachomatis bacteria responsible for?
1 - Tachoma (eye infection)
2 - Adult inclusion conjunctivitis
3 - Neonatal conjunctivitis
4 - Infant pneumonia
88
There are two reasons that chlamydia tachomatis is pathogenic. What are they?
1 - Direct destruction of host cell
| 2 - Host inflammatory response
89
Describe the direct destruction of the host cell
The bacteria get inside the host, grows, then lyses the host cell
90
Describe the host inflammatory response
Because of that growth, the host inflammatory response further exacerbates the tissue damage by responding to the organism
91
How can the organisms gain access to the cells?
Minute abrasions or lacerations
92
Can we see granuloma formation with chlamydia tachromitis?
YES!
93
What type of bacteria is chlamydia tachromitis?
Gram negative rod or cocci
94
Do patients that have had a chlamydia tachromitis infection have future immunity?
No... Immunity is NOT complete
95
Why can the immune response be damaging to the host even after the infection is gone?
It is damaging to the tissue because it continues to destroy host cells after the infection is gone because it is an intracellular bacteria
96
Are infections from chlamydia tachromitis mild or severe?
Can be mild OR severe
97
What can you see in a severe case of trachoma?
Eye infection that leads to scarring, development of granulomas, and a progression to blindness if not treated appropriately
98
There are four steps in the progression of trachoma. What are they?
1 - Follicular conjunctivitis
2 - Conjunctiva scarring
3 - Cornea abrasion
4 - Blindness
99
Describe follicular conjunctivitis, the first stage of trachoma progression
Diffuse inflammation and swelling of the eye
100
Describe the conjunctiva scarring seen in the second stage of trachoma progression
Conjunctiva scarring will occur because of granuloma formation
The eyelids will turn inward at this stage
101
Describe the conreal abrasions seen in the third stage of trachoma progression
Corneal abrasion will result from the eyelids being turned inward
102
When would the final stage of trachoma progression occur?
If you don't get the organism out of the eye by use of antibiotics, blindness will develop
103
What is adult inclusion conjunctivitis caused by chlamydia tachomatis?
An acute follicular conjunctivitis that is formed from the same serovars associated with a genital chlamydia infection
104
What population of individuals will typically develop adult inclusion conjunctivitis?
Sexually active adults - there is usually a relationship between the genital infection and the eye infection because we see it formed from the SAME serovars as the STD ***
105
What are the symptoms of adult inclusion conjunctivitis?
- Mucopurulent discharge (emission or secretion of fluid containing mucus and pus)
- Keratitis ( the eye's cornea, the front part of the eye, becomes inflamed)
- Corneal infiltrates (small patches of inflammatory cells associated with edema)
- Some vascularization of the conjunctivitis
106
What is neonatal conjunctivitis from chlamydia tachomatis?
It is an eye infection seen in infants that are exposed to C. tachomatis at birth
107
When will symptoms of neonatal conjunctivitis first develop?
5-12 days after birth - eyelids will swell
108
Untreated neonatal conjunctivitis may last up to _____ months
12
109
What symptoms will occur in cases of untreated neonatal conjunctivitis?
- Conjunctival scarring
- Corneal abrasion
- Increasing granuloma formation
110
Is the damage done from untreated neonatal conjunctivitis permanent?
Yes - it is mostly irreparable
111
What are untreated infants with neonatal conjunctivitis at risk for?
C. trachomatis pneumonia
112
When would you see the onset of infant pneumonia from chlamydia tachomatis?
2-3 weeks after birth
113
What are the symptoms of infant pneumonia?
- Bronchitis
- Dry cough
- Afebrile (not feverish)
- Trouble breathing
- Bilateral infiltrate of lungs
114
What was chlamydophila pneumoniae initially called before it was discovered what the causative agent actually was?
TWAR pathogen
| Tiwan acute respiratory agent
115
What does chlamydophilia pneumoniae cause?
- Pneumonia
- Bronchitis
- Sinusitis
116
How many infections of chlamydophilia pneumonia are seen annually in the US?
200,000 to 300,000
117
Is chlamydophilia pneumoniae more commonly seen in adults or children?
Adults
118
What percentage of the populations demonstrates serologic evidence of the infection?
50%
119
What does this mean?
Many people have been exposed to chlamydophilia pneumoniae and could have had a mild infection due to the pathogen
120
Do the most severe infections of chlamydophilia pneumoniae involve one or both lobes of the lungs?
Only one lobe
121
What will be on your differential list when working with a patient with a chlamydophilia pneumonia infection?
- Chlamyodphila pneumoniae
- Mycoplasma pneumoniae
- Legionella pneumophila
- Respiratory viruses
122
Is it easy to determine which of the four possibilities your patient actually has?
Not always... You will likely need to treat the patient for all of these
123
Chlamydophilia pneumoniae infection has also been like to cases of _________.
Atherosclerosis
124
What does this mean in a clinical sense?
There is evidence that this high incidence of exposure to chlamydophilia pneumoniae may be contributing to some cardiovascular disease
125
Case study: A 16-year-old girl presents with a cough of 3 weeks duration. The patient has mild but chronic shortness of breath, a persistent cough and noted malaise. What is the diagnosis upon x-ray?
Diagnosis: Interstitial pneumonia most prominent in the lower lobe of the left lung
126
The family had several parakeets in the home that were purchased from a roadside vendor. What is the significance of this?
Could have brought the infection into the home
127
How do you determine the causative agent of this pneumonia?
PCR (nucleic acid amplification) or complement fixation
128
If you believe it is a chlamydia organism causing the pneumonia, can you culture it to confirm?
NO - must use PCR or complement fixation, you CANNOT culture these organisms
129
What is the diagnosis?
```
Chlamydophilia psittaci
(common in bird species - AKA Parrot Fever)
```
130
What is the treatment for a pneumonia infection due to Chlamydophilia psittaci?
Antibiotic options
- Macrolides (erythromycin or azythromycin)
- Tetracycline
- Levofloxacin
Antibiotics must be administered for 10-14 days
131
Chlamydophilia psittaci commonly infects the ____________.
Respiratory tract
132
Where do these bacterial cell spread once they enter the respiratory tract?
***
Reticuloendothelial cells
***
133
What organs does this mean the bacteria will spread to?
Liver and spleen
134
What will the bacteria do once they reach these organs?
Multiply within the tissues of the liver and spleen - will produce focal necrosis (tissue death)
135
How is this bacteria "seeded" or spread to new areas of the body?
Hematogenous spread (i.e. by the blood)
136
Where will you see a lymphocytic inflammatory response?
In the alveolar and interstitial spaces of the lungs
137
What is the "moral of the story" for this case study?
Chlamydophila psittaci is associated with psittacine birds – parrots, parakeets, etc.
The moral is to obviously not buy your birds at a roadside stand
138
What are two main points from these two lectures on bacterial infections of the upper respiratory system?
- You can see how these organisms can cause infections in various areas of both the upper and lower respiratory tract
- There are some that you really NEED to differentiate between and there are some you won’t really be able to differentiate between
