Infection and Immunity Flashcards
1
Q
Give an example of an environmental cause of infection.
A
Ingesting contaminated food eg. Salmonella and cholera (water)
Contaminated air eg. legionella bacteria causing pneumonia (or contacts with surfaces)
2
Q
What is horizontal transmission in disease?
A
Person to person through contact, inhalation or ingestion of contaminants.
3
Q
What is vertical transmission in infection?
A
From mother to child during pregnancy or childbirth.
4
Q
What is the difference between an endotoxin and exotoxin in reference to bacteria?
A
Exotoxin - a chemical produced to elicit an immune response which aids its survival.
Endotoxin - inherent parts of the microorganism causing a host response.
5
Q
Give some examples of supportive diagnostic tests in suspected infection.
A
Full blood count - neutrophils and lymphocytes
C-reactive protein - acute phase protein in inflammation
Blood chemistry - shows liver and kidney function
Imaging - x-ray (lungs), ultrasound (heart), MRI (bowel)
6
Q
What does MCS stand for when identifying bacteria?
A
Microscopy
Culture
Antibiotic susceptibility
(Can also test for antigens and nucleic acids)
7
Q
How are viruses identified?
A
Antigen detection, antibody detection, viral nucleic acid detection
8
Q
What type of bacteria must parasitise cells?
A
Incomplete bacteria
Mycoplasma, chlamydiae, rickettsiae
9
Q
What are bacteriophages?
A
A virus which infects bacteria. Exchanges DNA such as for antibiotic resistance or toxin production
10
Q
What are plasmids?
A
Small circles of DNA with limited bacterial genes, usually antibiotic resistance medicines. Are transferrable between bacteria, including between species.
11
Q
What is the difference between aerobic and anaerobic bacteria?
A
Aerobes survive in the presence of oxygen
Anaerobes survive in the absence of oxygen
12
Q
Give an example of a disease which Staphylococcus aureus typically causes.
A
Pneumonia Meningitis Endocarditis Toxic shock syndrome Abcesses Sinusitis
13
Q
Where can Staphylococcus aureus normally be found without being pathogenic?
A
Respiratory tract and on the skin
14
Q
What is the different between alpha and beta haemolytic streptococci?
A
Alpha use hydrogen peroxide which oxidises haemoglobin, causing incomplete haemolysis.
Beta have streptolysin which causes complete haemolysis.
15
Q
What disease is commonly associated with Listeria monocytogenes?
A
Listeriosis
16
Q
What disease is commonly associated with Bacillus anthracis
A
Anthrax (cutaneous/pulmonary/gastrointestinal)
17
Q
What disease is commonly associated with Bacillus cerus?
A
Food poisoning (vomiting, diarrhoea, nausea)
18
Q
What diseases are commonly associated with Neisseria meningitidis?
A
Meningitis
Meningococcaemia (sepsis)
19
Q
What disease is commonly associated with Neisseria gonorrhoeae?
A
Gonorrhoea
20
Q
What areas of the body can be affected by Moraxella catarrhalis?
A
Respiratory system Middle ear Eye CNS Joints (septic arthritis in conjunction with bacteraemia)
21
Q
What diseases is Kleibsiella pneumoniae associated with?
A
Pneumonia Meningitis UTIs Bacteraemia Septicaemia
22
Q
What disease is Salmonella typhi associated with?
A
Typhoid fever (weakness, abdominal pain, constipation, headaches)
23
Q
What serious conditions can be associated with Haemophilus influenzae?
A
Bacteraemia
Pneumonia
Epiglottitis
Acute bacterial meningitis
24
Q
What diseases is Cryptococcus neoformans associated with?
A
Fungal meningitis
Encephalitis
(AIDS defining)
25
What is Pneumocystis jirovecj associated with?
```
Pneumocystis pneumonia
(AIDS defining)
```
26
What are dermatophytes?
A type of mold which causes infection of the skin, hair and nails, causing inflammation.
E.g. Ringworm and athlete's foot.
27
What disease is Plasmodium falciparum
Malaria
28
What is microbiota?
A collection of microorganisms on the skin and mucosal surfaces. They may normally be harmless or beneficial, but transfer to other sites can be harmful.
29
Give some factors which affect their susceptibility and response to infectious disease.
Age (extremes more susceptible, some diseases more prevalent at specific ages)
Gender (anatomy specific, men in general more susceptible)
Physiological state (pregnancy and stress increase risk)
Pathological state (poorly controlled diabetic, smoker, gestational diabetes)
Social (overcrowded, time in hospital)
30
Describe what is meant by contiguous spread in infectious disease.
Spread of infection along tissue planes or into local blood/lymphatic system i.e. Bacteria aspirated into the lungs from the oropharynx.
31
Describe what is meant by inoculation in the spread of infectious disease.
An injury which introduces a pathogen through the skin, such as a stab wound or scratch.
32
Describe what is meant by haematogenous spread of infectious disease.
When the blood stream transports a pathogen from one location to another, e.g. Superficial Staph aureus transferred to a heart valve, causing endocarditis
33
Why is debridement important when treating some infectious disease?
Dead and dying tissue makes an ideal breeding ground for anaerobic bacteria due to the low oxygen, lack of blood supply, and acidic pH.
34
Why is it important to remove dead space when preventing infectious disease?
The space can fill with serous fluid or blood which supports bacterial growth.
35
What are the ideal features of an antibiotic?
```
Selective toxicity
Few adverse effects
Reach site of infection
Oral or IV formulation
Long half life (so infrequent dosage)
No interference with other drugs
```
36
How does penicillin work?
Inhibit penicillin binding enzymes which normally cause cross linking of the cell wall. No linkage means integrity is damaged.
37
How does vancomycin work?
Binds peptide chains in the cell wall to stop penicillin binding proteins binding.
38
How does fluoroquinolone work?
Damages the coiling in nucleic acids to reduce synthesis
39
What are the mechanisms of resistance used by bacteria?
Drug inactivating enzymes (beta lactamases, aminoglycoside enzymes
Altered target to reduce affinity for antibacterials
Altered uptake - reduced permeability or increased efflux
40
Describe the difference between conjugation, transduction and transformation in horizontal gene transfer in bacteria.
Conjugation - plasmid transferred from one to another
Transduction - phages infect bacteria and transfer genetic material
Transformation - free DNA enters through pores
41
What is systemic inflammatory response syndrome (SIRS)?
An inflammatory state which affects the whole body
42
What is sepsis?
Systemic inflammatory response syndrome with an infection as the cause.
43
What symptoms/signs must a patient have two of to be diagnosed with sepsis?
Unusually high or low temperature
Raised heart rate
Raised respiration rate or low PACO2
White blood cell count is low
44
What is bacteraemia?
Presence of bacteria in the blood, with or without clinical features
45
What is septicaemia?
Clinical term meaning generalised sepsis (clinically unwell)
46
What is septic shock?
Severe sepsis with persistent hypotension despite IV fluid resuscitation
47
What type of bacteria is Neisseria meningitis?
Diplococcus, gram-negative
48
What effect do cytokines have on coagulation?
Inhibit thrombin production and fibrinolysis so promote coagulation.
49
What issues are caused by the coagulation cascade in sepsis?
Microvascular thrombosis leading to organ ischaemia, dysfunction and failure.
Microvascular injury is main cause of shock and multiorgan failure. Seen externally as progressive necrosis.
50
What urgent investigations should be carried out in suspected sepsis?
```
Full blood count, urea and electrolytes for kidney function
Blood PCR or culture to identify
Blood sugar
Liver function tests
C-reactive protein
Clotting studies
Blood gases
```
51
Why can you not perform a lumbar puncture with high intracranial pressure?
The decreasing pressure in the spinal cord forces the brain down through the foramen magnum (herniation) which can cause instant death.
52
Describe the differences between the innate and adaptive immune system.
Innate - immediate response, lack of specificity, lack of memory, no change in intensity.
Adaptive - slow, long-lasting protection, specificity, immunological memory, changes in intensity
53
What are the physical defences against pathogens?
Skin
Mucous membranes
Cilia
54
What are some physiological defences against pathogens?
Diarrhoea
Vomiting
Coughing
Sneezing
55
What are some chemical defences against pathogens?
```
Low pH
Antimicrobial molecules (IgG, lysozyme, mucous, defensins, gastric acid, pepsin)
```
56
What is the biological defence against pathogens?
Normal non-pathogenic flora in strategic positions which out-compete pathogens for attachment sites and resources.
Produce antimicrobial chemicals
57
What is the function of the spleen?
A filter for blood as part of the immune system.
Recycles old red blood cells.
Stores platelets and old white blood cells.
Helps to fight encapsulated bacteria.
58
What is the function of macrophages?
Sense harmful non self
Ingest and destroy microbes
Antigen presenting
Produce cytokines and chemokines
59
What is the function of monocytes?
Differentiate into macrophages after being recruited by cytokines.
60
What is the function of neutrophils?
Ingest and destroy pyogenic bacteria
61
What is the function of basophils?
Secrete anticoagulants and histamine
62
What is the function of eosinophils?
Attack multicellular pathogens (have IgE receptors)
63
What are the two ways that immune cells are able to recognise pathogens?
Toll-like receptors for pathogen-associated molecular patterns (PAMPs)
Opsonisation (C3b, C4b, IgG, IgM, CRP, MBL)
64
What is the function of C3a and C5a?
Recruit phagocytes
65
What is the function of C3b and C4b?
Opsonise pathogen
66
What is the function of C5-9?
Kill pathogens by making holes in the cell membrane
67
Describe how phagocytosis kills pathogens?
Engulf into phagosome
Fuses with lysosome to form phagolysosome
Forms residual body with the waste inside
Discharge outside the cell
68
What organs do TNF-alpha, IL-1 and IL-6 stimulate, and what do they stimulate them to do?
Liver - release opsonins (CRP, MBL)
Bone marrow - increase neutrophil mobilisation
Inflammatory activation - increases vasodilation, vascular permeability, and adhesion molecules
Hypothalamus - increase body temperature
69
What conditions or drugs can cause neutropenic sepsis?
Phenytoin
Leukaemia
Lymphoma
Chemotherapy
70
What is chronic granulomatous disease?
When phagocytes struggle to kill some types of bacteria and fungi as they can't form reactive oxygen compounds.
Granulomas form instead.
71
What are the principal methods of antibiotic resistance utilised by bacteria?
Inactivate the drug
Synthesise modified targets with reduced affinity
Reduce permeability
Actively export drugs
72
Give some principles of infection control with relation to the pathogen.
```
Use antibiotics (to treat and prophylactically)
Disinfectant
Ecological interaction with other bacteria (i.e. use of broad spectrum antibiotics that kill native flora, allowing C. diff to proliferate)
```
73
Give some principles of infection control with relation to the patient.
Restrict interaction with other patients, healthcare workers, and visitors e.g. with isolation
Optimise patient condition, such as stop smoking, lose/gain weight, optimise diabetic control
Use antimicrobial prophylaxis before surgery to reduce the risk of surgical site infections
74
Give some principles of infection control with relation to the practice in healthcare environments.
Policies and their implementation, must be carried out effectively by everyone
General and specific activity of healthcare workers. Ensure everyone washes their hands properly, uses aseptic technique ect.
Healthcare workers remain disease free and vaccinated
75
Give some principles of infection control with relation to the healthcare environment.
Fixed and variable features, such as types of chairs and curtains. Ensuring they are easily cleaned, non-porous
Enough wash basins which are regularly cleaned and used
76
What type of bacteria is Clostridium difficile?
Gram positive bacillus
77
What are the symptoms of Clostridium difficile infection?
Fever
Diarrhoea
Painful abdominal cramps
Toxic megacolon
78
What are the treatment and management options for a C. diff infection?
Stop other antibiotics if possible along with proton pump inhibitors, immunosuppressants, laxatives and opioids
Refer to an isolation ward
Treat with antibiotics according to severity (vancomycin, metronidazole, fidaxomicin)
79
Why is Staphylococcus aureus commonly seen in hospitals?
It is spread by human-to-human contact and respiratory secretions so common with so many people close together and when healthcare workers aren't cleaning properly or washing their hands before and after patient contact
80
Why is S. aureus often resistant to penicillin?
Produces beta-lactamases
81
What antibiotic is MRSA resistant to?
Meticillin
| * should use vancomycin
82
What type of virus is norovirus?
Single stranded RNA, non-enveloped
83
What type of bacteria is S. aureus?
Gram positive coccus
84
How can you reduce the spread of norovirus in a healthcare setting?
Minimise patient movement and interaction
Use soap and water for hand hygiene
Use gowns and gloves
Consider ward closure
Routine cleaning and disinfection
Exclude staff from work for a minimum of 48 hours after resolution of symptoms
85
Why are antigen presenting cells essential?
T cells are unable to detect pathogens alone
86
What are the strategic locations for antigen presenting cells?
Skin
Mucus membranes
Lymphoid organs (lymph nodes, spleen)
Blood circulation
87
Where are dendritic cells found?
Lymph nodes, mucus membranes, blood
88
Where are Langerhan's cells found?
Skin
89
How do T cells affect macrophages after presentation of an antigen?
Enhance the phagocytic action of macrophages
90
How to T cells affect B cells after presentation of an antigen?
Stimulate them to produce IgG which is more specific rather than IgM
91
What type of cells are class 1 major histocompatibility complexes on?
All nucleated cells
92
What type of microbe do class I MHCs present?
Intracellular
93
What type of T cell do class I MHCs present to?
CD8+ cytotoxic T lymphocytes
94
What cells are class II MHCs present on?
Dendritic cells
Macrophages
B cells
(These also have class I)
95
What type of microbe do class II MHCs detect?
Extracellular
96
What type of T cell do type II MHCs present to ?
CD4+ T helper cells.
97
What genetic features allow MHCs to be diverse in the same person?
Codominant expression so both inherited genotypes are expressed
Polymorphic so have a variable peptide binding cleft
98
Describe the endogenous pathway of antigen presentation.
Proteins present in the cytosol cleaved by the proteosome
Fragments transported to the ER where matching MHC forms a complex and transports to the cell surface
Both self and non-self presented to CD8+
99
Describe the exogenous pathway of antigen presentation.
Only seen in antigen presenting cells
After phagocytosis, proteins cleaved by the phagolysosome
Fuse with vesicle containing matching MHCII
Complex moves to the cell surface
Both self and non-self presented to CD4+
100
Where do T cells mature?
Thymus
101
What is produced by cytotoxic T lymphocytes to kill the host cell?
Perforins
| Granzymes
102
Describe the function of IgM
Activates complement
| Fast, strong, long duration, high affinity
103
What is the function of IgG
Stimulates Fc-dependent phagocytosis, used for passive immunisation in the short term
104
What is the function of IgE?
Immunisation against helminths
| Role in mast cell degranulation
105
What is the function of IgA?
Important role in mucosal immunity
106
Give some examples of methods of transmission in a travel related infection.
```
Food/water
Insect/tick bite
Swimming
Sexual contact
Animal bite/contact
Beach/recreation
Mosquitos
```
107
What tests would you do if you suspected someone who just returned from travelling abroad had an infection?
```
Full blood count - haemoglobin, platelets, lymphocytes, neutrophils, eosinophils
Urea and electrolytes (kidney function)
Liver function tests
Chest X-ray
Serology and PCR
```
108
What are the symptoms of malaria infection?
Fevers
Chills and sweats
```
Can then lead to:
Multiorgan failure
Tachycardia
Arrhythmia
Anaemia
Adult respiratory distress syndrome
Renal failure
Anaemia
Disseminated intravascular coagulation
Thrombocytopaemia
Bilirubinaemia
Diarrhoea
Hypoglycaemia
Metabolic acidosis
```
109
What is the traditional treatment for malaria?
Quinine
110
What organism causes enteric fever?
Salmonella enterica (gram negative bacilli)
111
What are the symptoms of enteric fever?
```
Dry cough
Relative bradycardia
Constipation
Haemorrhage or perforation of the intestine
Moderate anaemia
```
112
Give some conditions commonly associated with HIV infection.
```
Candidiasis
Kaposi's sarcoma
Pneumocystis pneumonia
Cryptococcal meningitis
Toxoplasmosis
Cytomegalovirus
HPV infection and cervical cancer
Mycobacterium avium complex
```
113
What type of virus is HIV?
RNA retrovirus
| Enveloped
114
What is the mechanism of transmission in HIV?
```
Sexual
IV drugs use
Vertical - breastfeeding/childbirth
Blood/blood product
Organ donation
Skin grafts
```
115
How does HIV infect cells?
Envelope proteins bind CD4+ receptors on T helper cells, allowing the entry of their contents.
Reverse transcriptase converts RNA to DNA which is inserted into the host genome.
116
What are the 4 stages of HIV infection?
Acute - high risk to pass on virus with high viral load. Can have flu-like symptoms. The body mounts a response which isn't fully effective
Latent - may be totally asymptomatic, struggle to clear the infection
Symptomatic - some serious infections begin to occur such as pneumonia
AIDS - severe infections
117
What is the management of HIV infection?
First treat the secondary infections
Test for the HIV antigen/antibody
Begin HAART straight away
Then use three drugs in combination, including two nucleoside reverse transcriptase inhibitors.
118
What are the acute symptoms of HIV infection?
```
Fever
Weight loss
Malaise
Myalgia
Sores in the mouth
Lymphadenopathy
Rash
Nausea/vomiting
Liver/spleen enlargement
```
119
What are the steps you should take after diagnosing someone with HIV?
Determine the source to reduce spread
Test partners and close family members
Avoid breastfeeding and provide prenatal antiretroviral therapy
PEP for patients with suspected or known exposure
PrEP for patients at high risk
120
What type of virus is hepatitis B?
dsDNA virus
121
How is hepatitis B transmitted?
Vertical - birth/breastfeeding/pregnancy
Sexual
IV drug use
Needlestick injury
122
How does hepatitis B cause its effects?
Viral genomic DNA is inserted into the host cell nucleus to replicate.
Primarily replicates in hepatocytes, and the immune response causes hepatocellular damage and viral clearance, mainly by cytotoxic T lymphocytes.
123
What are the symptoms of an acute hepatitis B infection?
```
Jaundice
Fatigue
Abdominal pain
Anorexia
Nausea
Vomiting
Arthralgia
```
124
What are the stages of hepatitis B infection?
Surface antigen shows within 6 weeks
Then e-antigen which is the highly infectious stage
IgM - core antibody. First to appear
e-antibody - non infective
surface antibody - recovery, virus cleared
IgG - core antibody which persists for life
125
What is the management of a hepatitis B infection?
Early antiviral treatment if the virus is particularly aggressive or if the patient is immunocompromised.
Check the serological status for stage of infection
No drugs to clear the infection but can stop it replicating
Acute infection generally won't require treatment.
126
Give a common commensal organism of the respiratory tract
Neisseria meningitidis
Streptococcus pneumoniae
viridans Streptococci
127
Give a common commensal organism of the intestine
Clostridium
| Bacterioids
128
Give some examples of prosthetic surfaces which can increase the risk of infection.
```
IV lines
Peritoneal dialysis catheters
Prosthetic joints
Cardiac valves
Pacing wires
Ventriculoperitoneal shunts
```
129
What is a vegetation?
A clot of platelets, fibrin, white blood cells, clotting factors, and bacteria if present which is able to build if there is damage to the endothelium.
They can embolise and cause damage elsewhere
130
Describe a biofilm.
Mucopolysaccharides embedding bacteria onto a surface, aiding them with adherence. This changes metabolism of the bacteria and acts as protection
131
What is quorum sensing?
Secretion of autoinducers by bacteria. Its concentration depends on the density of bacteria. This can trigger biofilm formation, sporulation and virulence factor secretion.
132
Describe a type I hypersensitivity reaction.
An allergy, occurs within 30 minutes
IgE
Occurs in people prone to them
Caused by environmental, non-infectious antigens
133
Describe a type II hypersensitivity reaction.
Antibody mediated 5-12 hours
IgG/IgM
Reaction to tissue or cell components
134
Describe a type III hypersensitivity reaction
Reaction to soluble antigens within 3-8 hours
IgG/IgM
Forms an immune complex, triggering the inflammatory process
135
Describe a type IV hypersensitivity reaction
Cell mediated within 24-48 hours
| Caused by self-antigens or environmental infectious agents
136
What is hypersensitivity?
An antigen-specific immune response which is inappropriate or excessive, resulting in harm to the host
137
What are the two phases of hypersensitivity?
Sensitisation - first encounter with the antigen. Is clinically silent.
Effector - clinical pathology upon re-exposure to the same antigen
138
What do mast cell granules contain?
Histamine
Leukotrienes
Prostaglandins
139
Describe the difference between the first and second exposure to allergens.
First - IgE mediated trigger of mast cells
Second - allergen cross-links with IgE on mast cells, directly activating them. Release of histamine, leukotrienes and prostaglandins is triggered. This can cause vasodilation, bronchial constriction, and increased vascular permeability
140
Give some common allergens
```
Dust mites
Cockroaches
Pollens
Medications
Animals
Latex
Foods
Insect venom
```
141
Why can there be clinical cross-reactivity between antigens?
They may have a strong homology with their proteins, such as peanuts and tree nuts
142
What are the skin manifestations of allergy?
Urticaria with erythema due to mast cell activation in the epidermis
143
What are the face manifestations of allergy?
Angioedema of the lips, eyes, tongue, and upper respiratory tract due to mast cell activation in the deep dermis
144
What are the systemic manifestations of allergy?
```
Hypotension
Cardiovascular collapse
Generalised urticaria
Angioedema
Breathing problems
```
Due to systemic mast cell activation
145
What is the treatment and management for an allergy?
```
Epinephrine
Antihistamines
Corticosteroids
Anti-IgE IgG
Allergen desensitisation
Avoid substance and high-risk situations
Educate
Medical alert bracelet
```
146
How does adrenaline help in an allergy?
Vasoconstriction to reverse hypotension and oedema
Increased heart muscle contraction
Inhibits mast cell activation
Monitor pulse, blood pressure, ECG and oximetry
147
How do you diagnose an allergy?
Clinical history
Blood tests for serum allergen (specific IgE)
Skin prick tests
Allergen challenge
148
What type of bacteria is Neisseria meningitidis?
Gram negative
| Diplococci
149
What type of bacteria is Staphylococcus aureus?
Gram positive
| Cocci
150
What type of bacteria is Escherichia coli?
Gram negative
| Rod
151
Streptococcus pneumoniae
Gram positive
| Diplococci
152
What type of bacteria is Haemophilus influenzae?
Gram negative cocci
153
What type of bacteria is Heliobacter pylori?
Gram negative
| Rod
154
What does it mean if a disease is endemic?
There is a normal background rate
155
What is an outbreak?
When two or more cases of disease are linked in time and place
156
What is an epidemic?
When the rate of infection is greater than the usual background rate
157
What is a pandemic?
When there is a very high rate of infection spreading across many regions, countries and continents
158
What is Ro?
The average number of cases that one case generates over the course of the infectious period in an otherwise uninfected, non-immune population.
159
Give some possible reasons for a new outbreak/epidemic/pandemic.
New pathogen - altered antigen/virulence factor/antibacterial resistance
New hosts - increased number immunosuppressed, more neonates
New practices - more liberal attitude to sex, not using barriers during sex, more IV drug use, high bed occupancy rates on a ward
New place - people moving to areas not previously colonised
160
What is meant by the term 'infectious dose'?
The number of microorganisms required to cause infection
161
What are some methods of infection intervention at a pathogen level?
Reduce or eradicate it (and the vector)
```
Antibacterial washes
Disinfectant
Decontamination
Sterilisation
Eliminate vector breeding sites
```
162
What are some methods of infection intervention at a patient level?
Nutrition
Medical treatment
Vaccination
IV immunoglobin
163
What are some methods of infection intervention in practice?
Use protective clothing
Behaviour changes e.g. Better food and drink prep/hand washing
Geographic - limit where you go
164
What are some methods of infection intervention at a specific location?
Safe water and air
| Quality of housing
165
Give some consequences of antimicrobial resistance.
Treatment failure
Prophylaxis failure
Economic costs
166
What does it mean if a bacteria is multidrug resistant?
They aren't susceptible to at least one agent in more than 3 antimicrobial categories
167
What does it mean if a bacteria is extensively drug resistant?
Not susceptible to one agent in two or less antimicrobial categories
168
What does it mean if a bacteria is pan-drug resistant?
Not susceptible to all agents in all antimicrobial categories
169
What evidence is there to show that antibacterials cause resistance?
Laboratory evidence gives biological plausability
Ecological studies relate community use to levels of resistance
Individual level data relates prior antimicrobial use to subsequent presence of antibiotic resistance
170
What are the principles of antimicrobial stewardship?
Appropriate use of antimicrobials
Optimal clinical outcomes
Minimise toxicity and other adverse effects
Reduce the cost of healthcare for infections
Limit selection for antimicrobial resistant strains
171
What are some persuasive methods of antimicrobial stewardship.
```
Education
Consensus
Opinion leaders
Reminders
Audit
Feedback
```
172
What are some restrictive methods of antimicrobial stewardship?
Restrictive susceptibility reporting
Formulary restriction
Prior authorisation
Automatic stop orders
173
What are some structural methods of antimicrobial stewardship?
Computerised records
Rapid lab tests
Expert systems
Quality monitoring
174
How can you measure the outcome of antimicrobial stewardship?
Patient outcome
Emergence of resistance
Clostridium difficile infection rate
175
How can chronic disease affect infection?
It changes the structure and function of affected tissues/organs which may alter the interaction between patient and microorganism
This may be affected by altered presence of microbes and their treatment
176
What is the progression of organisms which colonise people with cystic fibrosis?
Haemophilus influenzae
Staphylococcus aureus
Pseudomonas aeruginosa/Burkholderia
Atypical Mycobacteria/Candida albicans
177
What should you do with someone who has cystic fibrosis to reduce the risk of serious infection?
Physiotherapy
Antibiotics
Improve nutrition
178
What is significant about the mucoid strains of Pseudomonas aeruginosa?
They produce mucopolysaccharides for a biofilm.
179
What damage does COPD cause?
Breakdown of lung tissue
Small airway disease
Acute mucus production
Damaged cilia
180
What organisms commonly colonise the respiratory tract In COPD patients?
```
Streptococcus pneumoniae
Haemophilus influenzae
Moraxella catarrhalis
Pseudomonas aeruginosa
Escherichia coli
```
181
How does having diabetes increase infection risk?
Hyperglycaemia/acidaemia impair humoral immunity and polymorphonuclear leukocyte/lymphocyte function.
Micro/macrovascular disease reduces tissue perfusion, increasing infection risk
Diabetic neuropathy causing diminished sensation, resulting in unnoticed skin breaks
182
Describe malignant otitis externa in the context of diabetes
It starts externally, then spreads to soft tissue, cartilage, and bone
Severe ear pain and otorrhoea
Pseudomonas aeruginosa
Virtually exclusive to diabetes
183
Describe rhinocerebral mucormycosis in relation to diabetes.
Prevalent in poorly controlled diabetes, especially with diabetic ketoacidosis.
Colonise the nose and paranasal sinuses. Invade blood vessels, causing soft tissue necrosis and bony erosion
184
Why can people with diabetes mellitis be prone to urinary tract infections?
Neurogenic bladder defects prevent full emptying, holding bacteria in it.
185
What urinary tract infections are common in diabetes?
Pseudomonas aeuruginosa
| Enterobacteriaecea
186
Describe common variable immunodeficiency.
Inability of B cells to mature to plasma cells
187
What is the presentation of common variable immunodeficiency?
Upper and lower respiratory tract infections (can cause bronchiectasis)
GI complications (giardiasis)
Arthropathies (Mycoplasma/Ureaplasma)
Increased incidence of autoimmune disease (thrombocytopaenia)
Increased risk of lymphoma and gastric carcinoma
188
What is the management for common variable immunodeficiency?
Immunoglobin replacement therapy
Manage respiratory function
Avoid unnecessary exposure to radiation
Prophylactic antibodies
189
What are the manifestations of phagocyte defects?
```
Skin and mucus infections (ulcers)
Osteomyelitis
Deep abcesses
Catalase positive Staphylococcus infections
Invasive Aspergillosis (e.g. Pulmonary)
Inflammatory problems (granuloma)
```
190
Give an example of a phagocyte defect.
Cyclic neutropaenia
Leukocyte adherence deficiency
Chronic granulomatous disease
Chediak-Higashi syndrome
191
What is the management for phagocyte defects?
```
Prophylactic antibiotics/antifungals
Stem cell transplantation
Immunisation
Surgical management
Steroids (CGD)
```
192
Give an example of a T cell deficiency.
DiGeorge syndrome
| Severe combined immunodeficiency (SCID)
193
What is the presentation of severe combined immunodeficiency?
Failure to thrive
Deep skin and organ abcesses
Low lymphocyte count
High susceptibility to bacterial, fungal and viral infections
194
What is the management of severe combined immunodeficiency?
No live vaccines
Irradiated blood products
Aggressively treat infections
Bone marrow/stem cell transplantations before 3 months old
195
Give some causes of secondary immunodeficiency.
```
Malnutrition
Infection (HIV)
Liver disease
Lymphoproliferative diseases (cancer)
Splenectomy
```
196
What are some reasons for a splenectomy?
```
Infarction e.g. Sickle cell, coeliac
Trauma
Autoimmune haemolytic disease
Infiltration e.g. Cancer
Congenital
```
197
Why is the spleen essential?
Detects bloodborne pathogens, especially encapsulated bacteria, to opsonise them
Antibody production
Splenic macrophages remove opsonised microbes and immune complexes
198
What is the presentation in an asplenic patient?
Increased susceptibility to encapsulated bacteria
| OPSI
199
What is the management of asplenic patients?
Penicillin prophylaxis
Immunisation
Medic alert bracelet
200
How do beta-lactam antibiotics work?
They inhibit the action of penicillin binding proteins by directly binding to them.
201
What type of bacteria are penicillin antibiotics particularly active against?
Gram positive
202
Give an example of a penicillin antibiotic.
Penicillin
| Flucloxacillin
203
Give two classes of beta lactam antibiotics other than penicillins. How is their action different?
Cephalosporins
Carbapenems
They are active against gram negative organisms
204
How do glycopeptides work as antibiotics?
Bind to the cell wall to prevent penicillin binding proteins having action.
205
Give an example of a glycopeptide antibiotic.
Vancomycin
206
What type of bacteria are glycopeptide active against?
Gram positive
207
How do quinolones act as antibiotics?
Inhibit DNA gyrase to stop DNA synthesis
208
What type of bacteria are quinolones active against?
Gram negative
| Atypical
209
Give an example of a quinolone antibiotic.
Ciprofloxacin
| Fluoroquinolone
210
How do tetracyclines exhibit antibiotic action?
Inhibits tRNA binding to the A site of ribosomes
211
Give an example of a tetracycline.
Doxacycline
212
How do aminoglycosides exhibit antibiotic action?
Inhibiting protein synthesis by binding to the 30S ribosome
213
What type of bacteria are aminoglycosides active against?
Gram negative
214
Give an example of and aminoglycoside antibiotic.
Gentamycin
215
How do macrolides exhibit antibiotic action?
Binds to the 50S subunit of ribosomes to inhibit protein synthesis.
216
Give an example of a macrolide antibiotic.
Erythromycin
217
How does trimethoprim exhibit antibiotic action?
Inhibits folic acid synthesis
218
What type of virus is norovirus?
ssRNA non-enveloped
219
What type of bacteria is Clostridium difficile?
Gram positive bacillus
Spore forming
Obligate anaerobe
220
What type of bacteria is Salmonella enterica?
Gram negative bacillus
221
What type of virus is hepatitis B?
Partially dsDNA
222
What type of bacteria is Pseudomonas aeruginosa?
Gram negative bacillus
