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Infection Flashcards

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1
Q

What colour do gram positive bacteria stain?

A

Purple

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2
Q

What colour do gram negative bacteria stain?

A

Pink

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3
Q

What size peptidoglycan layer do gram positive bacteria have?

A

Thick

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4
Q

What size peptidoglycan layer do gram negative bacteria have?

A

Thin

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5
Q

Which bacteria have an outer membrane?

A

Gram negative

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6
Q

How much lipopolysachharide do gram positive bacteria have?

A

Low levels

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7
Q

How much peptidoglycan content do gram negative bacteria have

A

High content

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8
Q

Which type of bacteria are more resistant?

A

Gram negative

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9
Q

What type of bacteria tend to favour exotoxins instead of endotoxins

A

Gram positive

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10
Q

Which type of bacteria tend to favour endotoxins instead of exotoxins?

A

Gram negative

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11
Q

What are endotoxins?

A

Bacterial toxins consisting of lipids located within a cell

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12
Q

Name some gram positive cocci

A 
Staph aureus
Coagulase negative staph
Streptococcus pneumoniae
Strep pyogenes
Beta and alpha haemolytic strep
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13
Q

Name some gram positive bacilli

A

Clostridium difficile
Listeria monocytogenes
Bacillus anthracis
Bacillus lereus

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14
Q

Name some gram negative cocci

A

Neisseria meningitidis
Neisseria gonorrhoeal
Moraxella catarhalis

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15
Q

Name some gram negative bacilli

A

Escherichia coli
Haemophilus influenza
Klebsiela pneumoniae
Salmonella typhi

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16
Q

What are some key viruses to know?

A 
Adenovirus
Norovirus
Epstein Barr
HIV
Hepatitis
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17
Q

What are 2 classifications of fungi?

A

Yeasts and moulds

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18
Q

What are some examples of yeast infection

A

Candida albicans
Cryptococcus Noeformans
Pneumocystis jiroveci

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19
Q

What are some examples of mould infections?

A

Aspergillus

Dermatophytes (ring worm, athletes foot)

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20
Q

What are single cell fungi

A

Yeasts

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21
Q

What are the 2 classifications of parasites

A

Protozoa

Helminths

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22
Q

What are Protozoa

A

Single cell parasites

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23
Q

What are some examples of Protozoa?

A 
Malaria
Giardia Lambia
Cryptosporidium parvum
Plasmodium falciparum
Trypanesoma cruzi
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24
Q

What are some examples of helminths

A

Roundworms
Tapeworms
Flukes

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25
What is first line defence in inate immunity?
Barriers- physical, physiological, chemical, biological
26
What are some examples of inate immunity physical barriers?
Skin Mucousal membranes Bronchial cilia
27
What are some examples of inate physiological barriers
Vomiting Coughing Sneezing Diarrhoea
28
What are some examples of inate immunity chemical barriers?
Low PH of vagina, stomach, skin | Antimicrobial- IGA, lysozymes, gastric acid
29
What are biological barriers in reference to 1st line defecnce
Natural flora
30
What 3 things does the natural flora do that is beneficial for the host?
Competes for resources Produce antimicrobial Synthesise vitamins
31
What are some issues with normal flora?
Can be displaced out of its normal environment Can be pathogenic in immunocompromised Can be depleted by antibiotics
32
What are second line defences of the inate immune system?
Phagocytosis Opsinisation Complement system Cytokinesis
33
What do pathogens have on them that allow them to be detected non specifically? What are they
Pathogen associated molecular pattern PAMP | Carbohydrates, lipids, proteins, nucleic acids
34
What is a pamp and what is it recognised by?
Pathogen associated molecular pattern | Pathogen recognition receptors PRR
35
What's a PRR and what does it recognise
Pathogen recognition receptor- PAMPS
36
Aside from PAMPS what else can a pathogen have that will enhance recognition?
Opsonins attached
37
What are some examples of phagocytes that could be involved in the inate immune response
``` Macrophages Monocytes Neutrophils Basophils Eisonophils NKC Dendritic cells ```
38
What organs are macrophages present in?
All of them
39
What do macrophages present to? | What can they produce?
T cells | Cytokines/ chemokines
40
Monocytes are found where? What can they differentiate into?
Found in the blood | Macrophes or dendritic cells
41
Where are neutrophils found? How are they recruited in the inate immune response? What can they ingest?
In the blood Recruited by chemokines Ingest pyogenic species
42
Basophils/ mast cells are early actors in what?
Inflammation
43
Eisonophils are our defence mechanism against what?
Parasites
44
What do NKC target?
Abnormal host cells (virus, cancer)
45
What do dendritic cells do?
Present microbial antigens to T cells
46
What are some examples of opsonins
Complement: C3b, C4b Antibodies: IgG, IgM Acute phase proteins: CRP, mannose binding lectin MBL
47
Once a PRR has attached to a PAMP what happens?
Engulfment Phagolysosome formation Oxygen dependent and oxygen independent breakdown
48
What are some oxygen dependent examples of breakdown in the phagolysosome
Respiritory burst with oxygen radicals: Hydrogen peroxide Hydroxyl radicals NO
49
What are some oxygen independent actions in the phagolysosome
Lysozyme Transferrin Cationic proteins Proteolytic enzymes
50
What are the 2 complement pathways and how are they activate?
Alternate: initiated by cell surface microbial | MBL (classic)- when Manose binds to Manose binding lectin
51
What is the role of C3a and C5a in the complement pathway?
Recruit phagocytes
52
What is the role of C3b-C4b in the complement pathway
Opsinisation
53
What is the role of C5-C9 in the complement pathway
Membrane attack complex
54
Opsonins like IgM and IgG are essential in what? Especially when?
Clearing encapsulated bacteria | Especially in asplenic
55
What signals for cytokine release?
Toll like receptors (signalling PRR)
56
What's a signalling PRR
Toll like receptor
57
What are the 3 functional categories of cytokines
Cytokines that regulate inate Cytokines that regulate adaptive Cytokines that regulate haematopoesis
58
Cytokines that regulate the inate immune system are mostly produced by what
Macrophages and dendritic cells
59
What are some key inate immune response cytokines
TNF IL-1 IL-6
60
What 4 big affects do the cytokines TNF alpha, IL-1 and IL-6 have in the inate immune response
Stimulate liver Stimulate bone marrow Stimulate hypothalamus Stimulate inflammation
61
What effect does TNF, IL1 and IL6 have on the liver in the inate immune response
Production and excretion of CRP and MBL
62
What effect does TNF, IL1 and IL6 have on the bone marrow in the inate immune response
Neutrophil mobilisation
63
What effect does TNF, IL1 and IL6 have on the hypothalamus in the inate immune response
Stimulates an increase in body temp
64
TNF alpha, IL6 and IL1 stimulate inflammation in the inate immune response, what 4 things does this do
Vasodilation Increased vascular permeability Adhesion molecules Neutrophil attraction and invasion
65
What does a macrophage/dendritic cell do to initiate a adaptive immune response
Capture Process Present
66
Where are antigen presenting cells strategically located?
Skin (SALT) Mucous membranes (GALT, NALT, BALT, GUALT) Lymphoid organs Blood circulation
67
What antigen presenting cells are found in the skin
Langerhanns | Macrophages
68
What antigen presenting cells are found in lymphoid organs
B cells Dendritic cells Macrophages
69
What antigen presenting cells are found in mucous membranes
Dendritic cells | Macrophages
70
What can the 'Capture' Portion of capture process present be?
Phagocytosis (whole microbe) | Micropinocytosis (particles)
71
What does MHC stand for?
Major histocompatability complex
72
Where are MHC genes located
Chromosome 6
73
What HLA genes are present on all nucleated cells
HLA A/B/C
74
What do HLA A/B/C code for>
MHC class 1
75
What cells have HLA Dr/Dq/Dp ? | What does it code for?
Dendritic, macrophages, B cells | Class 2 MHC
76
What are some key features about the expression of class 1 and 2 HLA genes
Co dominant expression | Polymorphic genes
77
What do MHC class 1 present
Intracellular- virus, tumour, intracellular bacteria
78
What do MHC class 1 present to?
CD8
79
What is TAP and what is it to do with?
Transport associated presentation. Associated with MHC class 1 processing
80
Where do intracellular contents bind to the MHC1 molecule before presentation?
RER
81
What is a CD8 cell also known as?
T Killer cell
82
CD8 is associated with what adaptive immune response?
Cell dependent
83
When a CD8 cell beings to a MHC1 complex what is the result
Activation to a cytotoxic t lymphocyte. | Perforins and granzymes used on the infected cell
84
What MHCs are used in the cell dependent response?
Both MHC1 and MHC2
85
What is the role of MHC2 in the cell depdendent response?
Recruits CD4 TH1 cells
86
CD4 TH1 cells: What part of the adapative immune response? What do they secrete? What does that activate?
Cell dependent IFNg Activate B cells to make IgG antibodies and macrophages to phagocytise
87
What is costimulation in relation to the adaptive immune response?
Naive T helper cells receive cytokines co stimulation as well as MHC TH1, TH2, TH17
88
Where are MHC2 proteins exported from?
from the ER in a vesicle
89
What blocks the binding cleft of MHC2 protein?
Class2 associated invariant chain peptide CLIP
90
What removes CLIP to replace it with an antigen peptide, in the processing of an MHC2 protein?
HLA-DM
91
What do MHC class 2s present to?
CD4 cells- TH1,2,17
92
what are CD4 cells
T helper cells
93
What MHC is needed for the humoral response?
MHC2
94
In the humoral response what does MHC2 present to
CD4 TH2 and TH17
95
An important aspect of the binding clefts in MHC molecules is what?
They are highly polymorphic
96
In the humoral response. What CD4 cell attracts neutrophils? What does it use?
CD4 TH17 uses IL17 to attract neutrophils
97
What part of the humoral response recruits eosinophils? When would this happen What's secreted
MHC2-> CD4 TH2 To kill parasites Secreted IL-5 to attract eosinophils
98
How are B cells and Mast cells recruited in the humoral response?
CD4 TH2 (activated by MHC2) secretes IL-4, this attracts both mast cels and B cells
99
A B cell recruited by a TH2 CD4 cell will do what?
Differentiate into B memory Complete isotype switching and secrete antibodies Activating phagocytosis and complement
100
What does a mast cell secrete as an antibody
IgE
101
What is IgG when is it used
Antibody, FC dependent | Complement activation, neonatal immunity, toxins/virus neutralisation
102
What does IgM activate?
Complement
103
What does IgE do?
Provides immunity against helminths and mast cell degranulation
104
What is IgA for?
Mucousal immunity
105
What antibody is highest in initial exposure to a pathogen?
IgM
106
Which antibody is higher in exposure to the same pathogen on the second time?
IgG
107
What is a benefit of higher IgG on second exposure?
Faster, longer, higher affinity response
108
What is septic shock
Persisting hypotension, requiring treatment despite fluidn resuscitation
109
What is sepsis?
Life threatening organ dysfunction due to a dysregulated response to infection
110
What first has to happen before sepsis can begin to be set in motion?
The pathogen must enter the blood stream
111
What becomes amplified and dysregulated (mostly) in sepsis?
Cytokine release
112
What 4 big things does the amplified, dysregulated release of cytokines invoke in sepsis?
Increase vasodilation and capillary permeability Pyrexia induction at hypothalamus Coagulation, metabolism and neuroendocrine activation Post hyperinflammation induced immunoparalysis
113
What are 5 symptoms of sepsis
``` Decreased BP Raised HR Raised RR Temp up or down DIC ```
114
Why do we get increased HR in sepsis
There is a drop in BP, HR rises to compensate
115
Why is there a drop in BP with sepsis?
``` Mass vasodilation (distributorry) DIC ```
116
Why does RR rate increase in sepssis
As a response to hypoxia
117
What are the sepsis 6
Give 3- iv fluids, oxygen, IV ABx | Take 3- urine, blood cultures, lactate and FBC
118
Why give IV fluids in sepsis
Raise BP
119
Why give oxygen in sepsis
Patient likely hypoxic
120
Why measure urine output in sepsis
Decrease indicated organ failure
121
What does sepsis result in?
Multi organ failure
122
How can streptocccus be divided by haemolysis?
``` Alpha haemolytic (partial) Beta haemolytic (complete) Gamma haemolytic (no haemolysis) ```
123
How many different types of strep are there?
6
124
What haemolytic group is strep pneumonia
Alpha haemolytic
125
What streps are alpha haemolytic? What does this mean? What is seen on agar?
Strep pneumoniae and strep viridans Partially breaks down rbc Green halo
126
Does strep pneumoniae have a capsule?
Yes
127
What 4 main diseases can strep pneumonia cause?
Meningitis (no 1 cause in adults) Pneumonia (no 1 cause in adults) Otitis media Sinusitis MOPS
128
What are the 2 virulence factors that strep pneumonia has?
Capsule | IgA protease
129
Why is is important that strep pneumoniae has a IgA protease?
Because IgA is the main antibody in mucousal surfaces, where it mainly infects
130
What gram stain is strep pneumonia?
Gram positive diplodocus
131
Who is catalase positive? Strep or staph?
Staph
132
Which staph is coagulase positive? Staph aureus or staph epidermis?
Staph aureus
133
What gram stain is staph aureus
Gram positive cocci clusters
134
Why does staph aureus have a golden halo on blood agar?
It's a beta haemolytic and has broken down the RBC completely
135
What are 3 important endotoxins staph aureus has?
Protein A- binds antibodies at FC portion (less opsinisation) Coagulase- causes coagulation (fibrin strands around bacteria) allows it to cause abscesses Penicilinase- normal penicillins broken down, methicillin can in theory work but not in MRSA
136
What are 3 important exotoxins staph aureus has?
Exfoliatin- causes scalded skin syndrome Enterotoxin- cause gastroenteritis TSST-1- toxic shock syndrome
137
What disease can staph aureus cause from direct invasion
``` Almost every system Meningitis Acute bacterial endocarditis Pneumonia Sepsis UTI Osteomyelitis Septic arthritis Skin infection/ cellulitis ```
138
How do we treat staph aureus
Penicillinase resisitant beta lactams or 1st gen cephalosporins
139
How has MRSA changed to become resistant to Methicilin? What do we treat it with?
Developed a new penicillin binding protein | Vancomycin
140
What is staph epidermidis a normal part of the flora for? | What's the clinical relevance for this?
Normal skin flora | Contaminates samples frequently- urine and bloods
141
What does staph epidermidis form? Therfore what does it frequently infect?
Biofilm | Prosthetic joints, valves, IV lines
142
How does staph epidermidis cause infection? | How do we treat it? Why
By causing a biofilm | Vancomycin as the biofilm makes it very resistant
143
What gran stain is strep viridans
Postitive
144
What kind of haemolysis does strep viridans produce
Alpha
145
Why is it called strep viridans
Green from alpha haemolytic | Green salad gets stuck in your teeth
146
Where is strep viridans normal flora?
Oral and GI flora
147
How can strep viridans cause dental cavities?
Extracellular dextran
148
What can strep viridans do if it gets in the blood stream eg from dental work?
Sub-acute bacterial endocarditis (using dextran) strep sanguinus Can cause abscess anywhere (blood borne) strep intermedius
149
Where would the following sub species of strep viridans cause infection? Strep mutans Strep sanguinis Strep intermedius
Strep mutans- mouth Strep sanguines- heart valves Strep intermedius- blood borne tissue abscess
150
What is non multidrug resistant?
Not succeptible to 1 or less agents in 2 or less antimicrobial classes
151
What is MDR?
Multi drug resistant- non succeptible to at least 1 agent in 3 or more antimicrobial categories
152
What is XDR?
Extensively drug resistant- non succeptible to at least one agent in all but 2 or fewer categories
153
What is PDR
Pan drug resistant- not succeptible to all agents in all categories
154
What is antimicrobial stewardship
Coordinated interventions designed to improve the selection and use of antimicrobials
155
What kind of studies have demonstrated antibiotic resistance
Lab studies Ecological studies Individual level studies
156
What are the 3 main elements of antimicrobial stewardship
Persuasive- education, opinion leaders Restrictive- authorisation needed, stop orders etc Structural- records, lab tests
157
What are some examples of process measures in antimicrobial stewardship
Defined daily dose/1000 beds Adherence guidelines Benchmarking
158
What are some outcome measures of antimicrobial stewardship
Patient outcomes, infection rates, emergence of resistance
159
What defines a healthcare infection?
Onset at least 48 hours after admission
160
What are the more prevelant healthcare infection sites
UTI GI Surgical wound site Chest (pneumonia )
161
What are some viral examples of healthcare infection
HEP B, C, HIV Norovirus INfluenza
162
What are some bacterial examples of healthcare infections?
``` Staph aureus (MRSA) CDIFF ECOLI Klebsiella Pseudomonas ```
163
What re some fungal healthcare infections?
Candida | Aspergillus
164
The 4 ps that determine the likelihood of an acquired healthcare infection are what
4 ps Patient (are they imminsupressd, diabetic, obese) Pathogen (its virulence factors, ecological interactions) Practice (of healthcare workers the polices etc) Place (fixed and variable)
165
What are some examples of patient interventions to lower the risk of healthcare infections
``` Antibiotic prophylaxis Skin prep Hand hygiene Nutrition Screening ```
166
How can we reduce patient to patient transmission
Barrier nursing/ isolation
167
What are some enviromental interventions that can reduce the spread of healthcare infections
Layout ie where the sinks, toilets are etc Correct use of equipment Positive and negative pressure Rooms
168
What it the I face in identifying a potentially harmful pathogen?
``` Identify (A_F) Isolate Investigate Inform Initiate ```
169
What is the A-F in identifying harmful pathogens
``` Abroad? Blood borne? Colonised (MDR) Diarrhoea and vomiting Expectorating Funny looking rashes ```
170
What does person to person indirect require?
A vector such as a mosquito
171
What's an endemic disease?
It's usual background rate
172
What is an outbreak in relation to disease?
Two or more linked cases in time and place
173
What's an epidemic in relation to disease?
A rate of infection greater than the endemic rate
174
What is a pandemic in relation to disease?
Very high rate of infection spreading across regions
175
What is a pandemic often due to
Antigen shift, abrupt change in dna making everyone succeptible
176
What's antigen drift?
Slow change in dna of an infectious agent
177
What is the R0 of a pathogen?
The basic reproduction number. The average number of cases generated in a overwise healthy population
178
If R0 is equal to 1 what does that mean? What if its above 1
1=stable number of cases | Above 1 means its increasing
179
What can lead to an epidemic or pandemic
Sudden change in pathogen eg new virulence or resistance Change in practice or social behaviour Change in the patient that it can affect eg low immune
180
What determines how transmissible an organism is?
Infectious dose- the number of organisms required to cause infection
181
How is the infectious dose altered?
By the immunity of the hose and the virulence of the microorganism
182
What do we see graphically with epidemics?
Epidemic curves as cases slowly increase to peak of susceptibility then decrease
183
What is herd immuity
Vaccinating enough people to protect the vulnerable, decreased change of spread to almost 0
184
What does HIV make you more succeptible to?
Infections, in particular latent infections, fungus and Protozoa
185
In viruses how can the genetic material be stored?
DNA or RNA | Double strand or single strand
186
In Viruses they have a protein shell, whats it called?What shape can it be?
Capsid Helical (rod/coiled) Icosahedral (spherical)
187
A lipid envelope of a virus is derived from what?
Host cell membrane and has viral antigens
188
What does a HIV virus bind to and fuse with?
Binds to CD4 receptor and coreceptor (t helper cells, monocytes and macrophages)
189
How is the info/ genetics kept in the HIV virus
Single strand RNA (retrovirus)
190
Once the HIV virus has bound to CD4 receptor and coreceptor it empties its cellular contents, what happens?
The single strand RNA is converted too DNA by reverse transciptase
191
One HIVs rna has been converted to DNA heat happens in the CD4 cell?
The viral DNA is recombined into host DNA with integrase
192
Once HIVs viral DNA has been integrated into the host. What happens?
Sets of viral proteins are made | Immature viruses push out the cell taking some of the cell membrane with it
193
Once an immature HIV virus has pushed out of the host cell, how does it mature?
Proteases cut the protein chains, these are recombined to make a new mature virus.
194
How is HIV transferred ?
Bodily fluids with mucousal tissue/blood or broken skin
195
What happens to viral load with initial infection of HIV?
Initial massive increase
196
Why can you not test for HIV initially?
The virus is initially in the lymph tissue
197
What happens to CD4 initially with infection, then what happens?
Slight drop Recovers Slowly drops over time
198
What CD4 count in HIV is unsymptomatic
500 and above
199
What CD4 count constitutes AIDS
200 or below
200
How do you diagnose HIV, how long before its detectable?
Blood serology- HIV antigen, HIV antibody. | 4 weeks
201
The rapid HIV tests can be interpreted how?
If negative very accurate | If positive serology needed
202
How do anti-retro viral drugs target HIV
``` Inhibiting at 4 stages Entry to cell Reverse transcriptase Intergrase Maturation proteases ```
203
How do you treat HIV
2 nucleoside reverse transcriptase inhibitors and 1 of either: non-nucleoside reverse transcriptase inhibitors, protease inhibitor, integrase inhibitor
204
Why give 3 drugs in HIV retroviral treatment
Millions of viral replications and mutations occur, resistance develops quickly
205
What is hepatitis?
Inflammation of the liver
206
What systemic viruses cause collateral liver damage? | What is special about hepatitis
EBV, CMV | Hepatitis replicates specifically in hepatocytes
207
What HEPS cause chronic illness?
B C D with B
208
What is different about the structure of hep B compacted to A,C,D,E?
It is double stranded DNA and enveloped (c is also enveloped)
209
What genetic material do HEP A,C,D,E all have?
Single stranded RNA
210
HEP A C D E all share the fact that they are single stranded RNA. What seperated C from ADE?
C is enveloped icosahedral | ADE nonenveloped icosahedral
211
What is billirubin the breakdown of?
Haem
212
What does the liver do to billirubin?
Conjugates it
213
How does haem get converted to billlirubin, where does this happen?
Haem-> billivurdin-> billirubin | In the RES
214
How does billirubin travel in the blood stream?
With albumin
215
Where does conjugated billirubin go?
Either excreted as urine or to bile and then into the small intestine
216
What happens to conjugated billirubin in the small intestine (after being secreted as bile)
Conjugated billirubin-> urobillin-> stercobillin -> faeces
217
What 3 categories of jaundice are there? Ie where is it occurring
Prehepatic Cholestatic intrahepatic Cholestatic extrahepatic
218
What is prehepatic jaundice caused by?
Haemolysis
219
What are some examples of cholestatic intrahepatic causes of jaundice?
``` Viral hepatitis Drugs Alcoholic hepatitis Cirrhosis Autoimmune Pregnancy ```
220
What are some examples of cholestatic extrahepatic jaundice causes
Common duct stones, carcinoma of bile duct, billary stricture
221
How can we test liver function
billirubin levels Liver transaminases ALT, AST Albumin levels Coagulation
222
What indicates hepatocyte damage?
High ALT/AST
223
What does low albumin level indicate?
Liver isn't producing enough albumin
224
In liver damage what happens to coagulation tests
INR and prothrombin time rises
225
What does alkaline phosphotase measure?
Billary tract cell damage/ cholestasis
226
How is hep b transmitted in 75% of cases, how else can it get transmitted?
Vertical transmission 75% | Sexual content, IV, needle stick or blood exposure
227
What are some symptoms of hep B infection
Fatigue, jaundice, abdominal pain anorexic, arthralgia
228
What is the incubation period in hep b
6 weeks - 6 months
229
What levels ALT/AST is seen in hep b
In the 1000s
230
How many cases of hep B develop chroniciity?
10%
231
In hep B serology there are 2 antigens and 4 antibodies. What are these? In order of when they are seen in serology
``` Surface antigen E antigen Core antibody IGM E antibody HBeAB hep b e antibody Surface antibody HBsAB hep b surface antibody Core antibody IGG ```
232
In Hep B serology, what is the first thing to appear (within 6 weeks) what is accomponied with it?
Surface antigen appears Rise in ALT Hep B virus DNA (PCR to show viral load)
233
After the surface antigen is detectable in serology of hep B, what is next, what is important about this?
The E antigen presents HBeAg | Highly infectious
234
What follows the surface antigen and the e antigen in blood serology?
The core antibody IGM
235
After the core antibody is detectable in hep B serology, what is present, what does this signal?
The E antibody HBeAB. Signals the dissapearnace of the e antigen and its infectivity
236
What is the last antibody to appear in Hep B serology? What does it signal? What persists for life following hep B infection?
Surface antibody last to appear and signals viral clearance | IGG persists for life
237
How are HEP B infected patients managed?
Long term antivirals makes patient inactive carrier (low viral load and normal LFTs)
238
What does a hep B vaccine produce in patients?
The surface antibody response
239
What would someone who's recieved a vaccine for hep b have in serology, (what will they not have)
Surface antibody present | No surface antigen or core antibody.
240
What are 90% of the cases of hep C attributed to?
IVDU
241
How many hep C cases become chronically infected?
80%
242
What symptoms are associated with hep c?
80% have no symptoms. The rest are vague fatigue, anorexia, nausea, abdo pain
243
How do we test for hep C? When is it positive? What tests for chronic infection ?
Hep C antibody only present even after clearance or cure | Viral PCR for chronicity
244
What do we have for hep C that we dont have for hep B? | What do these not stop
Direct acting antiviral drugs | Don't stop reinfection
245
What is HIV PEP
Early initiation of anti-retro viral structure to reduce risk of HIV 3 ARVs for 28 days
246
What is a prion?
A chemical structure that can generate a copy of themeselves and spread person to person
247
What can prions withstand?
High temperatures
248
What are bacteriaphages
A virus within a bacteria
249
What bacteria can't survive outside of host cell?
Mycoplasma, chlamydiae
250
What classification system is used for viruses? | What does it seperate them based on?
Baltimore classification system Single strand or double strand RNA or DNA + sense or - Sense
251
What has to happen to + sense strand of RNA? In virus
Needs to be converted to be read by mRNA
252
What categories can DNA viruses be grouped into?
Single strand non enveloped Double strand non enveloped Double strand enveloped
253
RNA viruses can be classified as what
Single strand icosahedral + non enveloped Single strand icosahedral/helical + enveloped Single strand helical - enveloped Double strand icosahedral non enveloped
254
What can bacteria have that allow them to replicate and transfer generic information between bacteria?
Plasmids
255
How can cocci arrange?
Clusters and chains
256
What are some mechanisms of infection
``` Contiguous (direct spread) Ingestion Inhalation Vertical Via a vector Haematogenous Inoculation ```
257
What's the general timeline of infectio
``` Exposure Adherence Invasion Multiplication Dissemination ```
258
What's bacteriology?
Specimen growth on agar, use of antigen detection ad nucleic acid detection
259
What's virology
Antigen detection, antibod detection and viral nucleic acid detection
260
What are different types of antimicrobial
Antibacterial Antifungal Antiviral Antiprotozoal
261
What are 4 different ways we can classified antibacterials?
Bacteriacidal vs bacteriastatic Broad vs narrow spectrum Target site/ mech of action Chemical structure
262
What do you want in an antimicrobial agent
``` Selective toxicity Few adverse effects Oral and iv Long Half life No interactions ```
263
What are the 4 broad mechanisms of action that antibacterials use?
Cell wall synthesis Protein synthesis Cell membrane function Nucleic acid synthesis
264
What antibacterials affect cell wall synthesis
Beta lactams | Glycopeptide
265
What antibacterials affect protein synthesis
Tetracyclines Aminoglycosides Macrolides
266
What antibacterials affect cell membrane function
Polymixins
267
What antibacterials affect nucleic acid synthesise
Quinolones
268
How does penicillin work?
Penicillin binding protein acts to make cross links in cell walls, penicillin slots into this cross link section
269
What is vancomycin drug class? What does it inhibit?
Glycopeptide | Stops cross linking of cell walls
270
What do fluroquinlone inhibit?
The proteins associated with coiling and super coiling of DNA
271
What is intrinsic resistance?
There is no target or access for a drug to work. This is permanent
272
What is acquired resistance
The mutation or acquisition of genetic material resulting in its reistance (usually permanent)
273
What is adaptive resistance
The resistance caused by inducing stress on a microbe, usually reversible
274
What are some different mechanisms for resistance
Drug inactivating enzymes Altered targets with lower affinities for antibacterials Alter uptake eg pumps that remove antibiotics from cells
275
How can mutations occur?
Darwinian model or horizontal transfer
276
How do we measure antibiotic activity?
Disk sensitivity test
277
How do we work out the minimum inhibitor concentration?
Double the dilution until it isnt killing the organism
278
What fall under the category of beta lactams
Penicillins Cephalosporins Carbapenems
279
What is a typical broad spectrum beta lactam?
Meropenem
280
What are some different penicillins and what are they active against?
Penicillin- mainly streptococcus Amoxicillin- strep and some gram negatives Flucloxacillin- staph and strep
281
What do cephalosporins work against?
Broad spectrum but no anaerobe activity
282
When would we use glycopeptides like vancomycin
For gram positives when other agents arent working as toxic
283
When are tetracycline or doxycycline used?
Active against atypical pathogens in pneumonia
284
When is the aminoglycoside gentamicin used?
Gram negative. Works well in blood and urine. Reserved for gram neg sepsis Nephrotoxic
285
When are macrolides like erythromycin and clarithromycin used?
Alternative to penicillin for gram positives | Atypical resp infections
286
When are timethoprim or sulphonamides used?
UTI, inhibit folic acid synthesis
287
What do azoles do?
Antifungal that inhibit cell membrane synthesis | Flucanazole for candida
288
What do polyenes do?
Inhibit cell membrane function in fungi
289
What does aciclovir do? When would you use it?
Inhibit viral DNA polymerase | Herpes, encephalitis
290
What does osetamiver do?
Inhibits viral neraminidase in influenza a and b
291
Why do alpha haemolytic strep cause a wet appearance
Due to capsule
292
What is enterococcus faecalis haemolytic classification
Gamma/ non haemolytic
293
What lancefield classification is strep pyogenes
A
294
What lancefield b strep causes neonatal sepsis?
Agalactiae
295
What kind of capsule does strep pyogenes have?
Hyaluronic acid capsule- inhibits phagocytosis
296
What does the M protein on strep pyogenes inhibit?
Complement pathway
297
What does streptolysin O do?
Causes lysis of erythrocytes
298
What does streptokinase do?
Dissolution of clots converting plasminogen to plasmin
299
What causes strep pharyngitis?
Strep pyogenes
300
What's a complication of strep pharyngitis?
Scarlet fever | Acute rheumatic fever
301
Define sepsis
Life threatening organ dysfunction due to the dysregulated host response to infection
302
How do you analyse urine? | The presence of what indicates uti?
Dipstick Nitrites- some gram negs convert nitrate to nitrites Leukocyte esterase- enzyme released by neutrophils
303
What antibody is present in the mucous membranes
IgA
304
What antibodies are releaesed immediately after exposure to a new pathogen?
IGM
305
What antibody confers immunity to a disease?
IGG
306
What does cdiff exotoxin A do?
Damage intestinal mucousa
307
What does cdiff toxin b do?
Causes opening of tight junctions of intestinal epithelial
308
What can vancomycin be used for?
``` IV Skin infections Blood stream infections Endocarditis Bone and joint infections Meningitis caused by MRSA Orally CDIFF ```
309
What does vancomycin inhibit?
Cell wall synthesis in gram positive bacteria
310
When is ceftriaxone used in meningitis?
Caused by pneumococci Mengiococci Haemophilus influenza
311
How can ceftriaxone be administered
IV or IM
312
What can ceftriaxone be used to treat?
``` Middle ear infections Endocarditis Meningitis Pneumonia UTI Gonnorheoea ```
313
What class of antibiotic is ceftriaxone?
3rd gen cephalosporin within beta lactam family
314
What kind of bacteria does flucloxacillin treat? Is it narrow or broad spectrum?
Narrow spectrum | Gram positive bacteria
315
Would you use flucloxacillin for MRSA
No ineffective
316
What class of antibiotics is flucloxacillin
Beta lactam, penicillin class
317
What is metronidazole? What is the first line drug for?
Antibiotic and antiprotozoal | 1st line for C diff and often used for helicobacter pylori
318
What kind of action does metronidazole have?
Nitroimidazole- inhibits nucleic acid synthesis mainly in anaerobic cells
319
What is Aciclovir? What is t primarily used for treatment of?
Antiviral Herpes simplex, chickenpox, shingles Prevention of cytomegalovirus post transplant
320
What kind of spectrum does gentamicin have? What does it mainly target?
Broad | Gram negative
321
What bacteria is gentamicin used for? What is it not used for and why?
Pseudomonas, proteus, klebsiella, gram positive staph. | Not used for neisseria meningitis or gonorrhoeae as shock risk
322
How does gentamicin work?
Irreversibly binds to 30s ribosome subunit inhibiting protein synthesis. Similar to aminoglycosides
323
What is the drug of choice within the beta lactams? Why?
Amoxicillin. | Well absorbed
324
What is amoxicillin the first line treatment for?
Middle ear infection Pneumonia that isn't severe (with macrolide) Also effective for helicobacter pylori, strep throat, skin infections, UTI, strep, haemophilus, klebsiella
325
What is co-amoxiclav?
Amoxicillin with a beta lactamase inhibitor
326
What is trimethoprims primary use?
Bladder infections
327
How does trimethoprim work?
Inhibits reduction of dihydryfolic acid to tetrahydrofolic acid, essential precursor in thymidine synthesis
328
What's piperacillin? What's the primary use?
Broad spectrum beta lactam | Serious hospital acquired infections
329
What is meropenem? | What subgroup
ULTRA broad spectrum Carbapenem of beta lactam Gram pos and neg
330
What is tetracyclines primary use? What are not succeptible to it?
UTI, chlamydia, syphilus | Anaerobic
331
How does tetracycline work?
Protein synthesis inhibitor- inhibits mRNA ribosome
332
What does doxycycline work on?
Bacteria and protozoa Bacterial pneumonia Prophylaxis against pneumonia
333
How does erythromycin work?
Binds to 50s subunit inhibiting protein synthesis
334
Ciprofloxacin is what class? | What is it active against?
Broad spectrum fluoroquinilone | Gram positive and negative
335
Where is ciprofloxacins mechanism of action?
Inhibits DNA gyrase inhibiting cell division
336
What is oseltamivir?
Antiviral prevents influenza A and influenza B
337
What is flucanazole
Antifungal medication | Treats candidiasis
338
What's amphotericin?
Anti fungal for serious fungal infections and leishmaniasis
339
What's contagious spread?
Spread from physical contact or casual contact | Eg secretions, airborne , touch
340
What's non contagious spread
Via intermediate like mosquito pr non casual transfer of bodily fluid like sec
341
If you are vaccinated against hepatitis B what antibody would be seen on serology?
HBsAB
342
If you are not vaccinated but have acquired immunity to hep B what would serology show?
HBsAB | HBcAB
343
What fungal infection can be confused with strep pyogenes?
Oral candidiasis
344
What do the lesions in oral candidiasis look like?
Cottage cheese that bleeds when scraping
345
What cytokines acts on the hypothalamus to induce raised temp in infection?
IL-6
346
What causes the release of IL-6 to raise core body temp?
PAMP being recognised by Toll like receptor
347
What is mononucleosis caused by in 90% of cases?
EBV
348
What are some symptoms of mononucleosis?
Sore throat, fever, enlarged lymph nodes, tiredness
349
What happens in 1% of mononucleoiss cases?
Splenomegally leading to splenic rupture
350
What happens to blood lymphocytes in mononucleosis?
10% seen are atypical
351
What is mononucleosis often confused with?
Strep throat
352
What are the minority of cases of mononucleosis caused by?
CMV
353
Lipopolysachharide is more associated with what stain of bacteria?
Gram negative
354
What is the test to see how much antibiotic is needed called?
Minimum inhibitor concentration
355
Why is neisseria meningitidis toxic primarily?
LPS layer
356
What is EBV also called?
Human herpes 4 virus
357
Other than mononucleosis what is EBV associated with?
Hodgkin's lymphoma Burkett lymphoma Higher risk of autoimmune disease
358
How is EBV spread?
Via saliva and genital secretions
359
What does EBV infect?
B cells
360
What is EBV composed of?
Double helix of DNA surrounded by nuclear capsid surrounded by enveloped with lipids and glycoproteins
361
What does EBV demonstrate after not being active?
Latency
362
What is CMV also known as?
Human herpes 5
363
What does CMV strain for life once infected?
T cells
364
What are the main methods of transportation for CMV
Vertical | Saliva
365
What can CMV lead to?
CMV hepatitis, retitinitis, mononucleosis
366
What is the strong anti phagocytic virulence factor demonstrates by strep? How does it work?
M protein | Destroys C3 convertase preventing opsinisation
367
What is the quickest method to guide antibiotic choice?
Gram stain
368
What is a medical emergency associated with tonsillitis?
Peritonsilar abscess
369
What's helicobacter gram stain? | Usual location?
Gram negative | Stomach 80%
370
What does acute helicobacter pylori present as?
Acute gastritis with abdo pain
371
What risks are associated with helicobacter infection?
Peptic ulcer | Stomach cancer
372
What are some virulence factors associated with helicobacter pylori?
``` Hydrogenase that binds to hydrogen Biofilm Adhesins Flagella LPS ```
373
How does helicobacter pylori avoid acidic aspect of stomach?
Burrows into epithelium | Chemotaxis
374
How does helicobacter pylori cause its symptoms?
Distrupting tight junctions causing inflammmation
375
How do you treat helicobacter pylori infection?
Protein pump inhibit | Clarithromycin
376
What is isotype switching?
Change from IGM to IGG by changing heavy chain but keeping variable region the same
377
What are some reasons for an increase in foreign infections?
More exotic travel Immunocomprimised now able to travel Lots of migration
378
What are some key areas concerning travel related infection based on the infection model?
Calendar time- time with symtoms | Relative time- time since travel re incubation times
379
What foreign pathogen classes are particularly relevant, what do many use?
Parasites, bacteria like rickettsia and spirochaette. | Vectors
380
Why is a good travel history important?
Recognise imported rare diseases Recognise different strains of pathogens (antibiotic resistant etc) Protect lab and ward staff
381
What are some key questions re travel infections when trying to work out what pathogen it could be?
Where- what region travelled to When (symptoms started) What (symptoms) How (potential modes of transmission)
382
What are some key aspects of a travel history (which you may not ask in a normal history)
Anybody else in the group unwell An vaccine or prophylaxis use Recreational activities Healthcare exposure
383
What are the 4 main species of malaria?
Plasmodium falciparum Plasmodium ovale Plasmodium vivax Plasmodium malaria
384
What is the malaria vector?
Female anophelos mosquito
385
Where are the 3 locations of the malaria parasites life cycle?
Within the mosquito Within host liver Within host RBC
386
What's the minimum and maximum incubation period of malaria?
6-7 days min 6 months for P. Falciparum 12 months for P. Ovale and P. Vivax
387
What's the treatment for malaria?
P falciparum- quinine, doxycycline | P. Vivax/ovale chloroquinine
388
What tests are done for malaria
``` Blood smear (3 neg needed, parasite seen in RBC) FBC LFT Glucose CT head (risk of haemorrhage) CXR- risk of ARDS ```
389
What are signs of malaria onset?
Fever with +/- mild splenomegally | +/- myalgia, headache, chills, dry cough
390
What are some outcomes of sever P falciparum infection (2% and up)
``` ARDS Confusion/fits Thrombocytopenia DIC AKI Raised Billirubin (breakdown of RBC pre liver) ```
391
How can malaria be avoided
Ax risk Bite protect Chemoprohylaxis
392
What does salmonella typhi cause?
Enteric fever
393
How is salmonella typhi transmitted?
Fecal oral route
394
What kind of bacteria is salmonella typhi?
Enterobacteriae, gram negative bacilli
395
What allows salmonella typhi to adhere? Where does it do this?
Fibrimiae to the peyers patches
396
What allows salmonella typhi to grow intracellularly
Invasion
397
What are signs of enteric fever?
``` Systemic disease Fever Headache Dry cough Abdo pain Constipation *bradychardia ```
398
What's the incubation period for salmonella typhi
7-14 days
399
Whats a complication of enteric fever that can lead to death?
Intestinal haemorrhage and perforation
400
How do you investigate enteric fever?
Serology is unreliable so a blood culture or faeces culture needed
401
What's the treatment for enteric fever? | What's the prevention method"
Ceftriaxone or azithromycin | Food and hand hygiene, typhoid vacc
402
What can cause a widespread flat rash with confluent areas?
Rickettsia (spotted fever) Mononucleosis Childhood virus- measles, rubella Dengue
403
What's the most common arbovirus?
Dengue fever
404
How many serotypes of dengue fever are there?
4
405
What happens on 1st infection of dengue fever?
Anywhere from asymptomatic to severe afebrile. Lasts 1-5 days and improves 3 to 4 days after rash. Supportive Rx only
406
What happens when you get reinfected with dengue fever but a difference serotype
Dengue haemorhagic fever | Dengue shock syndrome
407
What gram stain is TB
Neither needs Ziehl-Neelsen staining
408
What is the immunocomprmised host
State in which immune system is unable to respond appropriately and effectively to infectious micro-organisms due to defect in one or more components of immune system
409
What are some cells of the inate rapid immune response
Granulocytes (BEN), dendritic cells, macrophage, mast, NKC
410
What are the cells of the adaptive slower immune response
B cell T cell CD4 CD8 NKC overlaps
411
Primary immunodefficency is a result of what?
Gene defect | Eg chronic granulomatous
412
Secondary immunodefficency us due to what?
Underlying disease state or treatment that causes either a decrease in the production of immune components or an increase in the loss or catabolism of immune components
413
What does SPUR refer to in reference to immune defficency
Severe Persistent Unusual Recurrent Infections suggest PID/Secondary
414
What is one of the major comorbidities associated with having an immunodefficency disorder
Cancer, in particular lymphoma | Different PID associated with different cancers
415
examples of PID due to antibody defficencies
``` Brutons disease (x linked recessive) Common Variable Immunodefficecny (CVID) Selective IGA defficency (often asymptomatic) ```
416
When do antibody defficency like CVID commonly present
6/12 to 5 years and 5 years up
417
What is an example of a combines T cell and B cell immunodefficency? When would it present? Why is it combined?
Severe combined immmunodefficency disorder SCID Presents younger than 6 months T cell defect therefore B cell due to co-activation
418
What's an example of a phagocytic defect PID? When would it present?
Chronic granulomatous disease Severe congenital neutropenia Below 6/12 or 6/12 to 5 years
419
What immunodefficency tend to present after the age of 5
B cell Antibody Complement Secondary
420
What would someone with a complement defficency struggle with? Therefore what would the likely presentation be? A c3 issue would cause what? A c5-9 would cause what
Struggle to clear encapsulated bacteria Chronic infections with N meningitidis, haemophilus influenza C3-pyogenic issue C5-9 meningitis/sepsis
421
What would someone with a phagocytic defect suffer from?
Recurrent skin and mucousal layer infections | FUNGAL infection such as aspergilllus
422
Somebody with an antibody defficency would be succeptible to what?
Unusual Upper resp tract infections | GIARDIA LAMBLIA GI infection
423
Someone with a T cell defect is succeptible to what?
Everything. Herpes simplex in particular
424
What are some supportive Mx for PID?
Prophylactic antibiotics Vit A and D Prompt Rx
425
What are some specific Mx plans for PID
Immunoglobulin therapy- CVID, Burtons | Haemopoetic stem cell transplant - SCID
426
Secondary immunodefficency due to decreased production of immune components can be caused by what?
``` Malnutrition Infection like HIV Liver disease (compliment made here) Lymphoproliferative disorders Asplenic ```
427
Why is the spleen so important? | What's OPSI
Only organ to remove blood borne pathogen, involved in IGM and IGG response, removes encapsulated bacteria. Removes opsonised microbes. OPSI- overwhelming post splenectomy infection
428
Haematological malignancies lead to 2nd immunodefficency how?
Chemo induced neutropenia Chemo induced mucousa damage Vascular catheters
429
An increase in the loss of catabolism of immune components leading to 2nd immunodefficency can be due to what?
Protein losing conditions Neprhopathy Burns
430
How would you test antibody function
Look at response to an already vaccinated microbe
431
What would you look at on the FBC to tell you about the cell mediated component
Lymphocytes
432
What would you look at on the FBC to tell you about the phagocytic portion of immune response
Neutrophil count
433
Microbes that cause infection can either be what?
Exogenous or commensal
434
How is the innate response described?
Non specific and rapid
435
What can the innate response recognise? How? What's a characteristic of this?
PAMPS using PRR. Recognises groups of pathogens so is not that specific but detects a wide range. Toll like receptor 4- LPS Toll like receptor 2- peptidoglycan
436
What bridges the inate and adaptive immune responders
Dendritic cells
437
What is immunisation
Activating the adaptive immune response with a less virulent analogue
438
What's the main portal of entry into the blood?
Poor dental hygiene-> dental extraction
439
In the inate immune response what 2 things detect invaders?
Phagocyte like macrophage and complement in blood
440
CD8 T cell are activated by what MHC? For intra or extra?
Intra MHC 1
441
How can B cells respond without T cells? What's the issue with this?
They can detect native proteins, lipids and LPS but need T cells for isotype switching to IGG
442
What's special about MHC1/2 between individuals?
We also process and present differently due to polymortphism
443
What happens in a viral infection to activate adaptive immune respnse
MHC1->CD8. CD8 needs co-signal from CD4 to become cytotoxic so MHC2 presents and activates CD4 to activate CD8
444
Why could you have a low CD8 in HIV
Low CD4 so less co-activation of CD8
445
How is a bacterial pathogen processed and presented?
MHC2-> CD4-> B cell-> antibodies
446
The key microbes for the module are? Gram pos-neg
Pos cocci- Staph and strep Pos bacilli- C Diff Neg cocci- N meningitidis Neg Bacilli- E. coli, salmonella typhi, haemophilus influenza, legionella pneumophilia
447
EBV and Herpes zoster share what ?
Family- both herpes | Cause latent infections
448
The 4 areas an ARV acts in HIV are?
HIV binding Reverse transcriptase Integrate (when it combines to host dna) Protease enzyme when virus protein chains are cut once leaving the cell
449
The Rx for meningococccal sepsis is what?
Ceftriaxone its a beta lactam, cephalosporin
450
The Rx for Cellulitis is what? And why?
Flucloxacillin- beta lactam, penicillin | Effective against strep and staph
451
The treatment for a UTI is? Likely causative orgnaism Action of antibiotic
Trimethoprim which inhibits folic acid synthesis | E Coli
452
The Rx for tonsillitis? And likely pathogen
Penicillin- beta lactam | Strep pyogenes

ESA 2 (10 decks)

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