Session 7 Flashcards
(116 cards)
1
Q
What is the colloquial name for Streptococcal pharyngitis?
A
Strep sore throat
2
Q
What is streptococcal pharyngitis an infection of?
A
Inflammation of the pharynx - the back of the throat including the tonsils
3
Q
Which bacteria cause streptococcal pharyngitis?
A
Group A streptococci
4
Q
Name two common symptoms of pharyngitis
A
Sore throat
Fever
5
Q
Is the cause of pharyngitis most commonly, viral or bacterial?
A
Viral
6
Q
Name three viruses that are known to cause pharyngitis
A
Adenovirus
Influenza virus
Epstein-Barr virus
7
Q
What is a fungal cause of pharyngitis?
A
Candida albicans
8
Q
What is the treatment for most cases of streptococcal pharyngitis?
A
Supportive treatments - usually gets better without antibiotics
9
Q
Cervical lymph nodes are common in…
A
Children
10
Q
When may cervical lymph nodes in children enlarge? They usually settle over a few…
A
With either viral or bacterial infection
Weeks
11
Q
What does EBV in the saliva infect to cause pharyngitis?
A
Epithelial cells and then B cells of the oropharynx
12
Q
What does EBV trigger in infected B cells?
A
B cell proliferation
13
Q
Which T cells recognise EBV infected cells and coordinate the response against them?
A
CD4+ T Cells
14
Q
Which type of T cell destroy infected EBV B/epithelial cells?
A
CD8+ T cells
15
Q
Which immunoglobulin is produced in the immune response against EBV infected cells in the oropharynx in pharyngitis?
A
IgM
16
Q
_______________ produced in response to EBV dramcatically activate the immune system
A
Cytokines
17
Q
The excess TNF and IL-6 produced in the immune response against EBV infected cells causes which symptoms for the patient with pharyngitis?
A
Fever
Fatigue
18
Q
What makes a host with EBV infected cells infectious?
A
Occasional bursts of lytic infection in oro-pharyngeal B cells
19
Q
What is endemic disease?
A
The usual background rate of disease
20
Q
What is an outbreak?
A
Two or mor cases linked in time and place
21
Q
What is an epidemic?
A
A rate of infection greater than the usual background rate
22
Q
What is a pandemic?
A
A very high rate of infection spreading across many regions/countries/continents
23
Q
What is meant by R0?
A
The average number of cases that one case generates over the course of its infectious period, in an otherwise uninfected, non-immune population
24
Q
What effect will an R0 > 1 have on the number of new cases of a disease?
A
Increase in cases
25
What effect will an R0 = 1 have on the number of new cases of a disease?
Stable number of cases
26
What effect will an R0 < 1 have on the number of new cases of a disease?
Decrease in cases
27
What are the 4 P's of infection prevention?
Pathogen
Patient
Practice
Place
28
What are three reasons/causes for outbreaks/epidemics/pandemics?
New pathogen
New hosts
New practice
29
What is meant by the term 'infectious dose'?
The number of microorganisms required to cause an infection
30
The infection dose of a microorganism varies by... (3)
The microorganism itself
Presentation of the microorganism
The immunity of potential host
31
Epidemic curves show...
The number of people infected by a disease at each time interval
32
Small scale outbreaks have a stochastic nature. What is meant by this?
They show a random pattern, so can be analysed statistically but not predicted precisely
33
Infection prevention related to PATHOGEN factors focuses on...
Reduction or eradication of the pathogen
34
What factors related to the pathogen can help in infection prevention?
Antibacterials
Decontamination
Sterilisation
35
What factors related to the vector can help in infection prevention?
Eliminate vector breeding sites
36
Infection prevention related to PATIENT factors focuses on...
Improved health/immunity
37
Infection prevention related to PRACTICE factors focuses on...
Avoidance of the pathogen or its vector
- Behavioural change
- Protective equipment
38
What is PPE?
Personal protective equipment involved in infection prevention - e.g. Gowns, Gloves and Masks
39
Give one example of a 'PLACE' factor involved in infection prevention
Well designed healthcare facilities - no 'nightingale' wards
40
What is a 'good' consequence of infection control/prevention?
Decreased incidence or elimination of a disease/organism
41
Give an example of two diseases which have benefited from a decreased incidence/elimination due to infection control/prevention
Smallpox
| Polio
42
Give two 'bad' consequences of infection prevention/control
Decreased exposure to pathogen ---> Decreased immune stimulus ---> Decreased antibody ---> Increased susceptibilities ---> Outbreak
Later average age of exposure ----> Increased severity
43
Give an example of 3 conditions where a later age of exposure results in increased severity
Polio
Hep A
Chicken pox
44
What is herd immunity?
The resistance to the spread of a contagious disease within a population that results if a sufficienctly high enough proportion of individuals are immune to the disease (vaccinated)
45
What type of bacteria is Staph aureus/MRSA?
Gram positive
| Cocci
46
What type of bacteria is Staph epidermis?
Gram positive
| Cocci
47
What type of bacteria is Streptococcus pneumoniae?
Gram positive
| Cocci
48
What type of bacteria is Viridans streptococci?
Gram positive
| Cocci
49
What type of bacteria is Streptococcus pyogenes?
Gram positive
| Cocci
50
What type of bacteria is Clostridium difficile?
Gram positive
| Bacilli
51
What type of bacteria is Neisseria meningitidis?
Gram negative
| Cocci
52
What type of bacteria is Escherichia coli?
Gram negative
| Bacilli
53
What type of bacteria is Haemophilus influenzae?
Gram negative
| Bacilli
54
Epstein-Barr Virus is a member of the __________ family
Herpes
55
What is the function of the first lines of defence of the innate immune system?
They prevent entry and limit growth of pathogens
56
The first lines of defence of the innate immunity include which 4 types of barriers?
Physical barriers
Physiological barriers
Chemical barriers
Biological barriers
57
What is the function of the second lines of defences of the innate immunity?
They contain and clear the infection
58
What are two examples of second lines of defence of the innate immunity?
What do both factors lead to?
Phagocytes
Chemicals (Complement, Cytokines)
Inflammation
59
Describe the stages of phagocytosis
Chemotaxis and adherence of microbe to phagocyte
Ingestion of microbe by phagocyte
Formation of a phagosome
Fusion of the phagosome with a lysosome to form a phagolysosome
Digestion of ingested microbe by enzymes
Formation of residual body containing indigestible material
Discharge of waste materials
60
What is the name given to the phagocytic vesicle that foreign material/microbes are ingested in by the phagocyte?
Phagosome
61
In phagocytosis, a phagosome fuses with a _______________ to form a ___________________
Lysosome
Phagolysosome
62
Give some examples of 'general' investigations for a possible infection
FBC
CRP
Imaging
Organ dysfunction tests
63
Give examples of what can be measured when investigating the host response in acute sepsis
Lactate
| Clotting factors
64
What factors are looked at when investigating organ dysfunction in a possible infection?
Liver function
Renal function
Oxygen saturation
65
Give examples of some specific investigations for possible infection
```
Culture
Antibiotic sensitivity
Gram stain
Antigen test
Antibody test
PCR for microbial DNA
```
66
Name two methods of testing antibiotic susceptibility
Disk-diffusion method
| Minimal inhibitory concentration
67
Treatment for an infection can be either...
Supportive
| Specific
68
Cefuroxime belongs to which antibiotic class?
What can it be used to treat?
Beta-lactams ---> Cephalosporins
Bronchitis
Gonorrhoea
69
What are some examples of specific treatments for disease/infection?
Surgery
| Antibiotics/Antivirals/Antiprotozoal
70
Describe the infection model
Pathogen + Patient (+ mechanism of infection) ---> Infection ---> Management ---> Outcome
71
What type of bacteria is Neisseria meningitidis?
Gram negative
| Diplococcus
72
Neisseria meningitidis can be normally found in the...
Nasopharynx
73
What is sepsis?
Life-threatening organ dysfunction due to a dysregulated host response to infection
74
What is an important virulence factor of Neisseria meningitidis?
LPS (endotoxin)
75
What is a specific treatment for meningitis caused by Neisseria meningitidis?
Ceftriaxone
76
What sort of rash can be seen in meningitis? How can it be tested for?
Purpuric rash
Tumbler test - doesn't disappear
77
Name three important virulence factors of Streptococcus pyogenes
M protein
Streptokinase
Streptococcal pyrogens exotoxins
78
How does M protein act as a virulence factor for Streptococcus pyogenes?
Gives resistance to phagocytosis
79
How do M proteins on Streptococcus pyogenes help in resistance against phagocytosis?
Inhibit activation of alternative complement pathway on bacterial cell surface
80
Are there more than one type of M protein on Streptococcus pyogenes?
Yes over 150 different serotypes (different antigens)
81
There are over 150 antigenically different serotypes of the M proteins found on Streptococcus pyogenes as a consequence of nucleotide variants of ________ gene
emm gene
82
How does streptokinase work as a virulence factor for Streptococcus pyogenes?
Dissolves clots through the conversion of plasminogen to plasmin
83
Streptokinase found in Streptococcus pyogenes converts ________________ to ___________
Plasminogen
Plasmin
84
How do streptococcal pyrogenic exotoxins act as virulence factors for Streptococcus pyogenes?
Cleaves IgG bound to Group A Strep
85
What do the streptococcal pyrogenic exotoxins released from Streptococcal pyogenes cleave?
IgG bound to group A strep
86
Antibodies consist of which two regions?
Variable region
Fc (Fixed component) region
87
Which types of blood cells produce antibodies?
B lymphocytes ---> Plasma cells
88
What is the first Ig produced in infection?
IgM
89
What is the most abundant Ig found in the body? When is it commonly seen?
IgG
Foetal development and in neonates
90
What is the second most abundant Ig in the body?
IgA
91
Where is IgA commonly found?
In secretions
E.g. Breast milk, mucus, saliva, tears
92
In which secretions is IgA found?
Breast milk
Mucus
Tears
Saliva
93
IgE is found in the body at what sorts of levels?
Low levels
94
Where are T cells produced? Where do they mature?
Bone marrow
Thymus
95
CD8+ T cells bind to antigens presented by which molecules?
MHC Class I molecules
96
CD4+ T cells bind to antigens presented by which molecules?
MHC Class II molecules
97
CD4 + T cells bound to antigens presented by MHC class II molecules activate B cells through the action of which proteins on which cells?
CD40L on CD4+ T cell
| CD40 on B cell
98
Give three examples of how mucus can act as a physical barrier against infection
Traps bacteria/pathogens
Contains enzymes such as lysozyme to degrade pathogens
Cilia beat away pathogenic mucus
99
Mucus contains antimicrobial enzymes including...
Lysozyme
100
Name the leukocytes
```
Neutrophils
Monocytes/Macrophages
Dendritic cells
Mast cells, basophils, eosinophils
Lymphocytes
```
101
Give three examples of lymphocytes
T cells
B cells
NK cells
102
Which leukocytes are phagocytes?
Neutrophils
Monocytes/Macrophages
Dendritic cells
103
Name 4 types of cytokines
Chemokines
Interferons
Interleukins
TNF
104
What is the function of chemokines?
They attract via chemical gradients
105
What is the function of interferons?
Anti-viral
106
What is the function of interleukins?
Modulate behaviour
107
What is the function of TNF?
Are pro-inflammatory
108
What is the specific function of IL-2 in an immune response?
T cell proliferation
109
What is the specific function of IL-10 in the immune response?
Anti-inflammatory
110
What is the common complement protein that all the pathways activating the complement cascade converge to?
C3
111
Which complement proteins are involved in the formation of a membrane attack complex?
C5-C9
112
How does the classical pathway of activating the complement cascade work?
Immune complexes bind to C1
| C1->C4->C2->C3
113
How does the MBL pathway of activating the complement cascade work?
MBL bind mannose contains residues in proteins on the bacterial cell walls mimicking the binding of immune complexes to C1
C1->C4->C2->C3
114
How are pathogens recognised in the innate immunity?
PRRs on immune cells recognise PAMPs on pathogen
115
What does the recognition of PAMPs by PRRs in the innate immunity result in?
Activation of mast cells/macrophages and the start of the inflammatory response
116
Once mast cells/macrophages are activated by the binding of PAMPs by PRRs in the innate immunity, what happens to each cell?
Mast cells produce histamine, TNF, LTs and chemokines
Macrophages (phagocytes) do phagocytosis
